The American Journal of Sports Medicine

There is no consensus regarding the best treatment approach for skeletally immature children with anterior cruciate ligament (ACL) injuries. High-quality studies with long-term follow-up are lacking, and evidence to support decision making is limited.

To evaluate functional and patient-reported outcome, surgical history, and complications among young adults who sustained an ACL injury before the age of 13 years and were treated with active rehabilitation and the option of delayed ACL reconstruction if needed.

Case series; Level of evidence, 4.

Forty-six children aged <13 years with a total intrasubstance ACL injury were included. None of these patients had additional injuries that warranted early surgery. At final follow-up at a mean 8 years after the time of injury, 44 patients remained in the study. The same test battery was conducted at baseline, 1 and 2 years, and final follow-up at approximately 18 years of age. The test battery included functional tests (hop tests and isokinetic muscle strength tests of quadriceps and hamstrings), patient-reported outcome measures (including the Knee injury and Osteoarthritis Outcome Score and the International Knee Documentation Committee Subjective Knee Form), and clinical examination. Medical records were reviewed to assess surgical history and complications.

At a mean 8 years of follow-up, 24 patients (55%) had undergone ACL reconstruction, and 16 (36%) had undergone meniscal surgery. Quadriceps muscle strength symmetry was >90% for 30 patients (68%). Mean leg symmetry indexes for hop and strength tests were consistently >90%, except for the single-hop test and hamstrings muscle strength for ACL-reconstructed knees. Mean ± SD International Knee Documentation Committee scores were 86.3 ± 13.7 for the ACL-reconstructed knees and 90.6 ± 11.8 for the nonreconstructed knees. At final follow-up, forty patients (91%) remained active in sports, but 29 (66%) restricted their activity level to nonpivoting sports.

Active rehabilitation may have a role in treatment of children with ACL injury. Approximately 50% of children may cope well, even to adulthood, without a surgical intervention. The other half may develop instability that warrants ACL reconstruction, and one-third may require meniscal surgery.

Many patients with anterior cruciate ligament (ACL) reconstruction who return to sport suffer new ACL injuries or quit sports soon after returning.

To prospectively follow a cohort of female soccer players with primary unilateral ACL reconstruction and matched knee-healthy controls from the same soccer teams to compare (1) the rate of new traumatic and nontraumatic knee injuries and other injuries, (2) the proportion of players who quit soccer, and (3) player-reported activity level and satisfaction with activity level and knee function.

Cohort study; Level of evidence, 2.

A total of 117 active female soccer players (mean ± SD age, 19.9 ± 2.5 years) 18.9 ± 8.7 months after ACL reconstruction and 119 knee-healthy female soccer players (19.5 ± 2.5 years) matched from the same teams were prospectively followed for 2 years for new knee injuries, other injuries, soccer playing level, activity level according to the Tegner Activity Scale, and satisfaction with activity level and knee function.

Players with ACL reconstruction had a higher rate of new ACL injuries (n = 29 vs 8; 19 vs 4 per 100 player years; rate ratio [RR], 4.82; 95% CI, 2.20-10.54; P < .001), other traumatic knee injuries (29 vs 16 per 100 player years; RR, 1.84; 95% CI, 1.16-2.93; P < .01), and nontraumatic knee injuries (33 vs 9 per 100 player years; RR, 3.62; 95% CI, 2.11-6.21; P < .001) as compared with controls. There was no difference in the rate of other (not knee) injuries (43 vs 48 per 100 player years; RR, 0.90; 95% CI, 0.65-1.23; P = .494). During the 2-year follow-up, 72 (62%) players with ACL reconstruction quit soccer, as opposed to 43 (36%) controls (P = .001). The median Tegner Activity Scale score decreased in both groups (P < .001) but more for the ACL-reconstructed group (P < .015).

Female soccer players with ACL reconstruction had nearly a 5-fold-higher rate of new ACL injuries and a 2- to 4-fold-higher rate of other new knee injuries, quit soccer to a higher degree, and reduced their activity level to a greater extent as compared with knee-healthy controls.

It is well accepted that there is a higher incidence of repeat anterior cruciate ligament (ACL) injuries in the pediatric population after ACL reconstruction (ACLR) with autograft tissue compared with adults. Hamstring autograft harvest may contribute to the risk for repeat ACL injuries in this high functional demand group. A novel method is the use of a living donor hamstring tendon (LDHT) graft from a parent; however, there is currently limited research on the outcomes of this technique, particularly beyond the short term.

The purpose was to determine the medium-term survival of the ACL graft and the contralateral ACL (CACL) after primary ACLR with the use of an LDHT graft from a parent in those aged less than 18 years and to identify factors associated with subsequent ACL injuries. It was hypothesized that ACLR with the use of an LDHT provides acceptable midterm outcomes in pediatric patients.

Case series; Level of evidence, 4.

Between 2005 and 2014, 247 (of 265 eligible) consecutive patients in a prospective database, having undergone primary ACLR with the use of an LDHT graft and aged less than 18 years, were included. Outcomes were assessed at a minimum of 2 years after surgery including data on ACL reinjuries, International Knee Documentation Committee (IKDC) scores, and current symptoms, as well as factors associated with the ACL reinjury risk were investigated.

Patients were reviewed at a mean of 4.5 years (range, 24-127 months [10.6 years]) after ACLR with an LDHT graft. Fifty-one patients (20.6%) sustained an ACL graft rupture, 28 patients (11.3%) sustained a CACL rupture, and 2 patients sustained both an ACL graft rupture and a CACL rupture (0.8%). Survival of the ACL graft was 89%, 82%, and 76% at 1, 2, and 5 years, respectively. Survival of the CACL was 99%, 94%, and 86% at 1, 2, and 5 years, respectively. Survival of the ACL graft was favorable in patients with Tanner stage 1-2 at the time of surgery versus those with Tanner stage 3-5 at 5 years (87% vs 69%, respectively; hazard ratio, 3.7; P = .01). The mean IKDC score was 91.7. A return to preinjury levels of activity was reported by 59.1%.

After ACLR with an LDHT graft from a parent in those aged less than 18 years, a second ACL injury (ACL graft or CACL injury) occurred in 1 in 3 patients. The 5-year survival rate of the ACL graft was 76%, and the 5-year survival rate of the CACL was 86%. High IKDC scores and continued participation in sports were maintained over the medium term. Importantly, there was favorable survival of the ACL graft in patients with Tanner stage 1-2 compared with patients with Tanner stage 3-5 over 5 years. Patients with Tanner stage 1-2 also had a significantly lower incidence of second ACL injuries over 5 years compared with those with Tanner stage 3-5, occurring in 1 in 5 patients. Thus, an LDHT graft from a parent is an appropriate graft for physically immature children.

Several single-nucleotide variants (SNVs) in collagen genes have been reported as predisposing factors for anterior cruciate ligament (ACL) tears. However, the evidence is conflicting and does not support a clear association between genetic variants and risk of ACL ruptures.

To assess the association of previously identified candidate SNVs in genes encoding for collagen and the risk of ACL injury in a population of elite female athletes from high-risk team sports.

Cohort study; Level of evidence, 2.

A total of 851 female Norwegian and Finnish elite athletes from team sports were included from 2007 to 2011. ACL injuries acquired before inclusion in the cohort were registered by interview. The participants were followed prospectively through 2015 to record new complete ACL injuries. Six selected SNVs were genotyped (COL1A1: rs1800012, rs1107946; COL3A1: rs1800255; COL5A1: rs12722, rs13946; COL12A1: rs970547).

No associations were found between ACL rupture and the SNVs tested.

The study does not support a role of the 6 selected SNVs in genes encoding for collagen proteins as risk factors for ACL injury.

Genetic profiling to identify athletes at high risk for ACL rupture is not yet feasible.

The effect of lateral meniscal posterior root tear and repair—commonly seen in clinical practice in the setting of anterior cruciate ligament (ACL) reconstruction—is not known.

This study evaluated the effect of tear and repair of the lateral meniscal posterior root on the biomechanics of the ACL-reconstructed knee. It was hypothesized that anterior tibial translation would increase under anterior loading and simulated pivot-shift loading with the root tear of the posterior lateral meniscus, while repair of the root tear would reduce it close to the noninjured state.

Controlled laboratory study.

Thirteen fresh-frozen adult human knees were tested with a robotic testing system under 2 loading conditions: (1) an 89.0-N anterior tibial load applied at full extension and 15°, 30°, 60°, and 90° of knee flexion and (2) a combined 7.0-N·m valgus and 5.0-N·m internal tibial torque (simulated pivot-shift test) applied at full extension and 15° and 30° of knee flexion. The following knee states were tested: intact knee, ACL reconstruction and intact lateral meniscus, ACL reconstruction and lateral meniscal posterior root tear, and ACL reconstruction and lateral meniscal posterior root repair.

In the ACL-reconstructed knee, a tear of the lateral meniscal posterior root significantly increased knee laxity under anterior loading by as much as 1 mm. The transosseous pullout suture root repair improved knee stability under anterior tibial and simulated pivot-shift loading. Root repair improved the ACL graft force closer to that of the native ACL under anterior tibial loading.

Lateral meniscal posterior root injury further destabilizes the ACL-reconstructed knee, and root repair improves knee stability.

This study suggests a rationale for surgical repair of the lateral meniscus, which can restore stability close to that of the premeniscal injury state.

First-time patellar dislocation with an associated chondral or osteochondral loose body is typically treated operatively to address the loose fragment. The incidence of recurrent instability in this patient population if the medial patellofemoral ligament (MPFL) is not reconstructed is unknown.

To determine the recurrent instability rate in patients undergoing surgery for patellar instability with chondral or osteochondral loose bodies, as well as to identify and stratify risk factors for recurrent instability.

Case series; Level of evidence, 4.

This was a retrospective analysis of adolescent patients treated operatively for acute patellar dislocation with associated chondral or osteochondral loose bodies between 2010 and 2016 at a single pediatric level I trauma center with minimum 2-year follow-up. Potential demographic, injury-related, radiographic, and surgical risk factors were recorded. The primary outcome variable was recurrent subluxation and/or dislocation. Secondary outcome variables included need for additional procedures, Kujala score, Single Assessment Numerical Evaluation (SANE) score, and patient satisfaction.

Forty-one patients were included. In total, 61% experienced recurrent instability at a mean follow-up of 4.1 years and 39% required subsequent MPFL reconstruction. Tibial tubercle-trochlear groove (TT-TG) distance greater than 15 mm was a risk factor for recurrent instability (P = .03). Patients with TT-TG distance greater than 15 mm and greater than 20 mm had recurrent instability rates of 75% and 86%, respectively. MPFL repair did not reduce the rate of recurrent instability (P = .87). Recurrent instability was associated with significantly worse mean Kujala (93.9 vs 83.0; P = .01), SANE (88.9 vs 73.1; P = .01), and patient satisfaction scores (9.4 vs 7.3; P = .002).

If the MPFL is not reconstructed during index loose body treatment, children have a 61% recurrent instability rate. Patients with TT-TG distance greater than 15 mm, and particularly greater than 20 mm, are at highest risk for recurrent instability.

Mosaicplasty and fresh osteochondral allograft transplantation (OCA) are popular cartilage restoration techniques that involve the single-stage implantation of viable, mature hyaline cartilage–bone dowels into chondral lesions of the knee. Recently, there has been greater focus on what represents a clinically relevant change in outcomes reporting, and commonly applied metrics for measuring clinical significance include the minimal clinically important difference (MCID) and substantial clinical benefit (SCB).

To define the MCID and SCB after mosaicplasty or OCA for the International Knee Documentation Committee (IKDC) subjective form and Knee Outcome Survey–Activities of Daily Living (KOS-ADL) and to determine patient factors that are predictive of achieving the MCID and SCB after mosaicplasty or OCA.

Cohort study (diagnosis); Level of evidence, 3.

An institutional cartilage registry was reviewed to identify patients who underwent mosaicplasty or OCA. The decision to perform either mosaicplasty or OCA was generally based on chondral defect size. The IKDC and KOS-ADL were administered preoperatively and at a minimum of 2 years postoperatively. Patient responses to the outcome measures were aggregated, and the MCID and SCB of these outcome scores were calculated with anchor-based methods. Multivariate analysis adjusted for age and sex was performed to identify patient factors predictive of achieving the MCID and SCB.

Of the 372 eligible patients, 151 (41%) were lost to follow-up, 46 (12%) had incomplete preoperative outcome scores and 2 were treated with OCA of the tibia and therefore excluded. In total, 173 knees were analyzed (n = 173 patients; mean age, 33.0 years; 37% female). Seventy-five (43%) and 98 (57%) knees were treated with mosaicplasty and OCA, respectively. The mean ± SD MCIDs for the IKDC and KOS-ADL were 17 ± 3.9 and 10 ± 3.7, respectively. The SCBs for the IKDC and KOS-ADL were 30 ± 6.9 and 17 ± 3.9, respectively. Univariate analysis demonstrated no association between procedure (mosaicplasty or OCA) and likelihood of achieving the MCID or SCB. In the multivariate analysis, lower preoperative IKDC and KOS-ADL scores, higher preoperative Marx Activity Rating Scale scores, lower preoperative 36-Item Short Form Health Survey pain scores, and a history of ≤1 prior ipsilateral knee surgical procedure were predictive of achieving the MCID and/or SCB.

These values can be used to define a clinically meaningful improvement for future outcome studies. For surgeons considering mosaicplasty or OCA for their patients, these results can help guide clinical decision making and manage patient expectations before surgery.

The association between patient satisfaction and patient-reported outcomes after cartilage repair is not well understood.

To investigate the association of patient satisfaction with pain, function, activity level, and quality of life after fresh osteochondral allograft (OCA) transplantation in the knee.

Case-control study; Level of evidence, 3.

This study comprised 371 patients (396 knees) who underwent primary OCA transplantation for osteochondral lesions in the knee between 1997 and 2015. Mean ± SD patient age was 31.8 ± 11.6 years, and 62% were male. The majority of grafts (62%) were located on the femoral condyle; the mean number of grafts per knee was 1.5 ± 0.8; and the median graft area was 6.9 cm² (range, 1.8-50 cm²). Pain, function, activity level, and quality of life were evaluated pre- and postoperatively via International Knee Documentation Committee scores and Knee injury and Osteoarthritis Outcome Scores. Patient satisfaction with the results of the OCA transplantation was assessed postoperatively. All follow-up evaluations occurring at postoperative 1 year or later were included in the analysis.

The mean follow-up time was 5.5 years. Overall, the satisfaction rate was 88.1%, and this rate was constant over time. Satisfaction rates varied by diagnosis, age, sex, and anatomic location of the allograft. Postoperative International Knee Documentation Committee pain, function, and total scores differed between patients who were satisfied and not satisfied (all P < .001). All Knee injury and Osteoarthritis Outcome Score subscale results differed between those who were satisfied and not satisfied (all P < .001). Having a diagnosis of osteochondritis dissecans was the only variable that predicted which patients would be satisfied with the results of the allograft, after controlling for age, sex, anatomic location of the graft, and number of grafts.

A consistently high and durable patient satisfaction rate after OCA transplantation was found. Satisfied patients reported lower pain and higher function, activity levels, and quality of life as compared with patients who were not satisfied. Patients with osteochondritis dissecans had a particularly high level of satisfaction with the OCA procedure.

F18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT) can be used to assess changes in the metabolism of an anterior cruciate ligament (ACL) graft as it is undergoing “ligamentization.” Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is the preferred modality for noninvasive assessment of graft structure and graft vascularity.

To compare the use of F18-FDG PET/CT and DCE-MRI to assess ligamentization within the ACL graft and correlate the results with clinical tests.

Case series; Level of evidence, 4.

Among 30 recruited patients, 27 patients (3 females and 24 males) completed 2 follow-up assessments at a mean of 125 ± 22 days and 259 ± 38 days after arthroscopic ACL reconstruction. At both assessments, anterior drawer test, Lachman test, and Lysholm scoring (LS) were conducted. Images from F18-FDG PET/CT and MRI were analyzed qualitatively and quantitatively (maximum standardized uptake value [SUVmax], SUVmax ratio to the contralateral side [SUVmax CL], normalized enhancement [NE]) in 3 zones: femoral, intra-articular (IA), and tibial. Of the 27 recruited patients, 1 patient had reinjury due to a fall. Therefore, 26 patients were considered for the final analysis.

A significant improvement (P = .0001) was found in median LS, from 78.5 (range, 62-90) to 94.5 (range, 84-100), at the second follow-up. All grafts were found to be viable on PET/CT and vascularized on MRI. All grafts were seen as continuous on MRI, with exception of 1 graft at the second follow-up. Dynamic MRI identified single-vessel supply to all of the grafts at the first follow-up and multiple-vessel supply in 10 patients at the second follow-up. Reduction in the median SUVmax, SUVmax CL, and NE at second follow-up was seen in all 3 zones. Only SUVmax CL in the IA zone showed a significant reduction (P = .032); patients with excellent LS at the second follow-up showed significantly higher reduction (P = .005) than patients with good LS. NE in the IA zone was correlated (0.39; P = .048) with LS only at the first follow-up, whereas SUVmax CL (–0.52; P = .006) and SUVmax (–0.49, P = .010) in the IA zone negatively correlated with LS at the second follow-up only. No correlation was observed between PET/CT and MRI parameters.

Glucose metabolism and vascularity in the graft tissue can be used to assess ligamentization of ACL graft. A viable and vascularized graft at first follow-up is associated with good to excellent final outcome, regardless of LS at this stage. Since no correlation was observed between PET/CT and MRI parameters, they may be assessing different domains of the same process. Higher NE in the IA zone at the first follow-up and lower SUVmax CL in the same region at second follow-up are associated with better outcome.

Changes in knee kinematics after anterior cruciate ligament (ACL) injury may alter loading of the cartilage and thus affect its homeostasis, potentially leading to the development of posttraumatic osteoarthritis. However, there are limited in vivo data to characterize local changes in cartilage thickness and strain in response to dynamic activity among patients with ACL deficiency.

The purpose was to compare in vivo tibiofemoral cartilage thickness and cartilage strain resulting from dynamic activity between ACL-deficient and intact contralateral knees. It was hypothesized that ACL-deficient knees would show localized reductions in cartilage thickness and elevated cartilage strains.

Controlled laboratory study.

Magnetic resonance images were obtained before and after single-legged hopping on injured and uninjured knees among 8 patients with unilateral ACL rupture. Three-dimensional models of the bones and articular surfaces were created from the pre- and postactivity scans. The pre- and postactivity models were registered to each other, and cartilage strain (defined as the normalized difference in cartilage thickness pre- and postactivity) was calculated in regions across the tibial plateau, femoral condyles, and femoral cartilage adjacent to the medial intercondylar notch. These measurements were compared between ACL-deficient and intact knees. Differences in cartilage thickness and strain between knees were tested with multiple analysis of variance models with alpha set at P < .05.

Compressive strain in the intercondylar notch was elevated in the ACL-deficient knee relative to the uninjured knee. Furthermore, cartilage in the intercondylar notch and adjacent medial tibia was significantly thinner before activity in the ACL-deficient knee versus the intact knee. In these 2 regions, thinning was significantly influenced by time since injury, with patients with more chronic ACL deficiency (>1 year since injury) experiencing greater thinning.

Among patients with ACL deficiency, the medial femoral condyle adjacent to the intercondylar notch in the ACL-deficient knee exhibited elevated cartilage strain and loss of cartilage thickness, particularly with longer time from injury. It is hypothesized that these changes may be related to posttraumatic osteoarthritis development.

This study suggests that altered mechanical loading is related to localized cartilage thinning after ACL injury.

The rate of septic arthritis in the knee after anterior cruciate ligament (ACL) reconstruction varies in the literature but is generally less than 1%. It has been reported to be higher in professional athletes (5.7%).

The primary goal was to evaluate the rate of septic arthritis after ACL reconstruction in professional athletes compared with other patients. The secondary goals were to analyze the risk factors; increased cost of infections; return to sport, satisfaction, and functional results at 1-year follow-up; and resolution rate of infections at final follow-up.

Case-control study; Level of evidence, 3.

This retrospective analysis of prospective data included a continuous series of patients who underwent isolated ACL reconstruction between 2012 and 2016. The main outcome criterion was the development of intra-articular infections in the operated knee. An infection was suggested clinically (knee pain with fever and/or chills) and confirmed bacteriologically in deep tissue samples obtained during revision surgery. All infected patients underwent an emergency reoperation with lavage and debridement along with dual antibiotic therapy first by an intravenous route and then orally for 6 weeks.

A total of 1809 of 1859 patients included in the cohort during this period fulfilled inclusion criteria; there were 1632 (90.2%) who underwent primary reconstruction and 177 (9.8%) who underwent revision. The series included 1249 (69%) men and 560 (31%) women, with a mean age of 29.1 ± 9.8 years. Ninety-eight percent of the patients participated in a sport, including 90 (5.0%) at a professional level and 712 (39.4%) competitively. Septic arthritis of the knee developed after a mean 15.7 ± 5.5 days in 7 (0.38%) patients: 5 of 1632 (0.31%) who underwent primary reconstruction and 2 of 177 (1.13%) who underwent revision. Septic arthritis did not develop in any professional or competitive athletes; all affected patients were recreational athletes (P = .02). The risk factors identified for the development of septic arthritis on multivariate analysis were prior knee surgery (odds ratio [OR], 15; P = .002) and hemarthrosis during the immediate postoperative period (OR, 127.2; P = .002). There were no recurrent infections after a mean follow-up of 2.8 ± 1.2 years.

None of the professional athletes in this cohort had septic arthritis after ACL reconstruction. There are no particular precautions to be taken in this population. The risk factors identified for the development of septic arthritis on multivariate analysis were prior knee surgery and hemarthrosis during the immediate postoperative period. Similar to all studies published on the subject, there were very few infected patients, which limits the identification of risk factors.

NCT02511158 (ClinicalTrials.gov identifier)

Controversy surrounds the classification and treatment of hips with a lateral center-edge angle (LCEA) between 18° and 25°. It remains undetermined as to whether periacetabular osteotomy (PAO) or arthroscopic surgery is best used to treat this patient population.

Patients with hip pain and mild or borderline acetabular dysplasia defined by an LCEA between 18° and 25° have different features of acetabular and femoral morphology, as determined by other relevant radiographic measures assessing the anterior and posterior acetabular walls, anterior coverage of the femoral head by the acetabulum, and femoral head and neck junction sphericity.

Cross-sectional study; Level of evidence, 3.

A retrospective review of patients who had an LCEA between 18° and 25° undergoing hip preservation between January 2010 and December 2015 with either PAO or hip arthroscopic surgery was performed. Anteroposterior, Dunn lateral, and false profile radiographs were used to measure the LCEA, Tönnis angle, anterior center-edge angle (ACEA), anterior wall index (AWI) and posterior wall index (PWI), femoral epiphyseal acetabular roof (FEAR) index and posterior to anterior wall index, and alpha angle and femoral neck-shaft angle. An agglomerative hierarchical clustering analysis was then performed on the continuous radiographic variables to identify different subtypes of hip pathomorphology among the study cohort. There were sex-specific trends in hip morphology. Therefore, we proceeded to perform separate cluster analyses for each sex. Multivariate logistic regression was used to identify radiographic parameters for distinguishing between female patients who underwent hip arthroscopic surgery versus PAO.

Ninety-eight patients with hip pain and an LCEA between 18° and 25° underwent surgery in the study period, 77 (78%) were female, and 81 (82%) had complete radiographs for cluster analyses. The mean age was 22.6 years. Hip arthroscopic surgery was performed in 40 (41%) patients, and PAO was performed in 58 (59%) patients. The ACEA (45%), FEAR index (34%), and AWI (30%) were the most commonly abnormal radiographic parameters among all patients. In female patients, the ACEA (55%), FEAR index (42%), and AWI (34%) were the most commonly abnormal radiographic parameters. In male patients, the PWI (48%) was the most common radiographic abnormality. For female patients, 3 clusters representing different patterns of hip morphology were identified: acetabular deficiency with cam morphology, lateral acetabular deficiency, and anterolateral acetabular deficiency. For male patients, 3 clusters were also identified: posterolateral acetabular deficiency with global cam morphology, posterolateral acetabular deficiency with focal cam morphology, and lateral acetabular deficiency without cam morphology. The ACEA (odds ratio [OR], 47.7 [95% CI, 9.6-237.6]; P < .001) and AWI (OR, 3.9 [95% CI, 1.0-15.0]; P = .049) were identified as independent factors predicting which procedure was performed in female patients.

A comprehensive evaluation of radiographic parameters in patients with an LCEA between 18° and 25° identified sex-specific trends in hip morphology and showed a large proportion of dysplastic features among these patients. An isolated assessment of the LCEA is an oversimplistic approach that may jeopardize appropriate classification and may provide insufficient data to guide the treatment of hips with additional features of dysplasia and instability.

Appropriate patient selection is critical when hip arthroscopy is considered in the setting of borderline dysplasia (BD). It is presumable that excessive femoral anteversion (EFA) and BD may contraindicate arthroscopy.

Patients with combined EFA and BD (EFABD) demonstrate significantly inferior short-term outcomes after arthroscopic labral preservation and capsular closure when compared with a similar control group with normal lateral coverage and femoral anteversion.

Cohort study; Level of evidence, 3.

Data were prospectively collected and retrospectively reviewed on patients undergoing hip arthroscopy between April 2010 and November 2014. The EFABD group’s inclusion criteria were BD (lateral center-edge angle, 18°-25°), labral tear, capsular closure, and femoral version ≥20°, as well as preoperative modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score–Sports Specific Subscale, and visual analog scale. Exclusion criteria were workers’ compensation, preoperative Tönnis grade >1, microfracture, abductor pathology, or previous ipsilateral hip surgery or conditions. Patients in the EFABD group were matched 1:2 to a similar control group with normal coverage and femoral anteversion by age at surgery ± 6 years, sex, body mass index ± 5, acetabular Outerbridge grade (0, 1 vs 2, 3, 4), and iliopsoas fractional lengthening.

Sixteen EFABD cases were eligible for inclusion, and 100% follow-up was obtained at ≥2 years postoperatively. Twelve EFABD cases were matched to 24 control cases. Mean femoral version was 22.4° in the EFABD group and 10.2° in the control group (P = .01). Mean lateral center-edge angle was 22.1° in the EFABD group and 31.5° in the control group (P < .0001). Acetabuloplasty was performed significantly more frequently in the control group (P = .0006). No other significant differences were found regarding demographics, findings, procedures, or preoperative scores. At latest follow-up, the EFABD group demonstrated significantly lower mean modified Harris Hip Score (76.1 vs 85.9; P = .005), Nonarthritic Hip Score (74.8 vs 88.5; P < .0001), Hip Outcome Score–Sports Specific Subscale (58.3 vs 78.4; P = .02), and patient satisfaction (7.1 vs 8.3; P = .005). There were 4 secondary surgical procedures (33.3%) in the EFABD group and 1 (4.2%) in the control group (P = .03). One patient in each group required arthroplasty.

Patients treated with arthroscopic labral preservation and capsular closure in the setting of EFABD demonstrated significant improvements from presurgery to latest follow-up. However, their results are significantly inferior when compared with a matched-controlled group. Consideration of periacetabular osteotomy or femoral osteotomy may be warranted in the setting of EFABD to achieve optimal benefit.

Prolonged disease chronicity has been implicated as a cause of suboptimal clinical outcomes after hip arthroscopy for femoroacetabular impingement syndrome (FAIS), possibly due to disease progression, deconditioning, and the development of compensatory pathomechanics.

To evaluate the effect of increasing duration of preoperative symptoms on patient-reported outcomes, reoperation, and clinical failure of hip arthroscopy for FAIS.

Cohort study; Level of evidence, 3.

A retrospective cohort study was performed to identify all patients undergoing primary hip arthroscopy between January 1, 2012, and July 30, 2014, by a single surgeon, with minimum follow-up of 2 years. Patient demographics, comorbid medical conditions, and preoperative outcome scores were compared between patients with preoperative symptoms lasting less than 2 years and those with symptoms lasting 2 years or longer. Multivariate regressions were used to compare Hip Outcome Score Activities of Daily Living (HOS-ADL), Hip Outcome Score Sport-Specific (HOS-SS), and modified Harris Hip Score (mHHS) between the 2 cohorts at 2 years of follow-up.

A total of 624 patients were included, with an average age of 34.0 ± 13.5 years; 235 (37.7%) patients had experienced preoperative symptoms 2 years or longer. Patients with symptoms lasting less than 2 years had statistically significant higher outcome scores than those with symptoms lasting 2 or more years for the HOS-ADL (86.3 ± 16.4 vs 80.3 ± 19.9, respectively), HOS-SS (75.0 ± 25.3 vs 65.1 ± 29.0), and mHHS (79.1 ± 16.6 vs 74.0 ± 18.8), as well as higher satisfaction (82.1 ± 30.7 vs 71.1 ± 31.6) and lower pain scores (2.6 ± 2.3 vs 3.5 ± 2.6). On multivariate analysis, patients with symptoms 2 years or longer had significantly higher visual analog scale–Pain score (β = 0.6, P = .039) and lower HOS-ADL (β = −3.4, P = .033), HOS-SS (β = −6.3, P = .012), and satisfaction (β = −6.7, P = .028) at 2-year follow-up. Patients with longer duration of symptoms also demonstrated less improvement in HOS-SS (β = −10.3, P = .001) at 2 years after surgery. Patients with symptoms for 2 years or longer were significantly less likely to achieve a patient acceptable symptomatic state for HOS-ADL (relative risk [RR] = 0.8, P = .024) and HOS-SS (RR = 0.8, P = .032) at 2 years of follow-up. Patients with symptoms 2 years or longer also demonstrated significantly higher rates of revision arthroscopy (RR = 10.1, P = .046).

Patients with untreated, FAIS-related symptoms lasting 2 years or longer before arthroscopic management had significantly worse patient-reported outcomes and higher rates of reoperation at 2 years after surgery when compared with those patients with a shorter duration of preoperative symptoms.

Ankle sprains are the most common musculoskeletal injury in the United States. Chronic lateral ankle instability can ultimately require operative intervention to decrease pain and restore stability to the ankle joint. There are no anatomic studies investigating the vascular supply to the lateral ankle ligamentous complex.

To define the vascular anatomy of the lateral ligament complex of the ankle.

Descriptive laboratory study.

Thirty pairs of cadaveric specimens (60 total legs) were amputated below the knee. India ink, followed by Ward blue latex, was injected into the peroneal, anterior tibial, and posterior tibial arteries to identify the vascular supply of the lateral ligaments of the ankle. Chemical debridement was performed with 8.0% sodium hypochlorite to remove the soft tissues, leaving casts of the vascular anatomy intact. The vascular supply to the lateral ligament complex was then evaluated and recorded.

The vascular supply to the lateral ankle ligaments was characterized in 56 specimens: 52 (92.9%) had arterial supply with an origin from the perforating anterior branch of the peroneal artery; 51 (91.1%), from the posterior branch of the peroneal artery; 29 (51.8%), from the lateral tarsal branch of the dorsalis pedis; and 12 (21.4%), from the posterior tibial artery. The anterior branch of the peroneal artery was the dominant vascular supply in 39 specimens (69.6%).

There are 4 separate sources of extraosseous blood supply to the lateral ligaments of the ankle. In all specimens, the anterior talofibular ligament was supplied by the anterior branch of the peroneal artery and/or the lateral tarsal artery of the dorsalis pedis, while the posterior talofibular ligament was supplied by the posterior branch of the peroneal artery and/or the posterior tibial artery. The calcaneofibular ligament received variable contributions from the anterior and posterior branches of the peroneal artery, with few specimens receiving a contribution from the lateral tarsal or posterior tibial arteries.

Understanding the vascular anatomy of the lateral ligament complex is beneficial when considering surgical management and may provide insight into factors that lead to chronic instability.

The modified Jobe and docking techniques are the 2 most commonly employed techniques for ulnar collateral ligament (UCL) reconstruction among overhead athletes. However, no study has directly compared these techniques performed by a single surgeon. Current comparisons of these techniques have relied solely on systematic reviews and biomechanical studies.

There will be no difference in outcomes or return to play between the modified Jobe and docking techniques in elbow UCL reconstruction surgery.

Cohort study; Level of evidence, 3.

Twenty-five modified Jobe and 26 docking UCL-reconstructive surgical procedures were performed by a single surgeon, each with a minimum 2-year follow-up. Kerlan-Jobe Orthopaedic Clinic (KJOC) score, Conway Scale, years played, sex, handedness, sport, position, palmaris versus gracilis graft type, concomitant or future arm/shoulder injuries, and need for additional surgery were compared between the groups. Patients who underwent future shoulder or elbow surgery, no matter the cause, were included.

No difference was seen between the modified Jobe and docking reconstruction cases in regard to KJOC scores (mean ± SD: 78.4 ± 19.5 vs 72.0 ± 26.0, P = .44), Conway Scale (return to play, any level: 84% vs 82%, P = .61), years played (14.7 ± 6.2 vs 15.2 ± 5.8, P = .52), sex (P = .67), handedness (P ≥ .999), sport (P = .44), position (P = .60), level of competition (P = .59), and future surgery (12% vs 4%, P = .35). Palmaris graft type had significantly higher KJOC scores than hamstring grafts (82.3 ± 20.0 vs 57.9 ± 21.2, P = .001). The mean follow-up was 6.1 years in the modified Jobe group and 7.3 years in the docking group (mean = 6.7, P = .47).

The modified Jobe and docking techniques are both suitable surgical options for elbow UCL reconstruction. There was no statistically significant difference between the techniques in regard to return to play, KJOC score, or need for subsequent surgery at 6.7-year follow-up. This is the first direct clinical comparison of these 2 techniques by a single surgeon at midterm follow-up.

The ulnar collateral ligament (UCL) microstructural organization and collagen fiber realignment in response to load are unknown.

The purpose was to describe the real-time microstructural collagen changes in the anterior bundle (AB) and posterior bundle (PB) of the UCL with tensile load. It was hypothesized that the UCL AB is stronger and stiffer with more highly aligned collagen during loading when compared with the UCL PB.

Descriptive laboratory study.

The AB and PB from 34 fresh cadaveric specimens were longitudinally sectioned to allow uniform light passage for quantitative polarized light imaging. Specimens were secured to a tensile test machine and underwent cyclic preconditioning, a ramp-and-hold stress-relaxation test, and a quasi-static ramp to failure. A division-of-focal-plane polarization camera captured real-time pixelwise microstructural data of each sample during stress-relaxation and at the zero, transition, and linear points of the stress-strain curve. The SD of the angle of polarization determined the deviation of the average direction of collagen fibers in the tissue, while the average degree of linear polarization evaluated the strength of collagen alignment in those directions. Since the data were nonnormally distributed, the median ± interquartile range are presented.

The AB has larger elastic moduli than the PB (P < .0001) in the toe region (median, 2.73 MPa [interquartile range, 1.1-5.6 MPa] vs 0.65 MPa [0.44-1.5 MPa]) and the linear region (13.77 MPa [4.8-40.7 MPa] vs 1.96 MPa [0.58-9.3 MPa]). The AB demonstrated larger stress values, stronger collagen alignment, and more uniform collagen organization during stress-relaxation. PB collagen fibers were more disorganized than the AB during the zero (P = .046), transitional (P = .011), and linear (P = .007) regions of the stress-strain curve. Both UCL bundles exhibited very small changes in collagen alignment (SD of the angle of polarization) with load.

The AB of the UCL is stiffer and stronger, with more strongly aligned and more uniformly oriented collagen fibers, than the PB. The small changes in collagen alignment indicate that the UCL response to load is due more to its static collagen organization than to dynamic changes in collagen alignment.

The UCL collagen organization may explain its susceptibility to injury with repetitive valgus loads.

The arthroscopic “bony Bankart bridge” (BBB) repair technique was recently shown to successfully restore shoulder stability at short-term follow-up, but longer-term outcomes have not yet been described.

To report the outcomes at minimum 5-year follow-up after BBB repair for anterior shoulder instability with a bony Bankart lesion.

Case series; Level of evidence, 4.

Patients were included if they sustained a bony Bankart lesion, were treated with a BBB technique, and were at least 5 years postoperative. Patients were excluded if they underwent concomitant rotator cuff repair or an open bone fragment reduction. All patients were assessed with the following measures preoperatively and at final evaluation: QuickDASH (Quick Disabilities of the Arm, Shoulder and Hand), American Shoulder and Elbow Surgeons, Single Assessment Numeric Evaluation, and 12-Item Short Form Health Survey (SF-12) Physical Component Summary.

From 2008 to 2012, 13 patients who underwent BBB met the inclusion criteria with a mean age of 39.6 years (range, 19.1-68.8 years) and a mean follow-up of 6.7 years (range, 5.1-9.0 years). Mean time from most recent injury to surgery was 6.3 months (range, 1 day–36 months). The mean glenoid bone loss was 22.5% (range, 9.1%-38.6%). Mean SF-12 scores demonstrated significant improvement from 45.8 (SD, 9.7) preoperatively to 55.1 (SD, 5.9) at a mean follow-up of 6.7 years. At final follow-up, the mean American Shoulder and Elbow Surgeons score was 93.1 (range, 68.3-100); the mean QuickDASH score, 6.2 (range, 0-25); and the mean Single Assessment Numeric Evaluation score, 92.8 (range, 69-99). None of the patients progressed to further shoulder surgery. Three of 13 patients (23%) reported subjective recurrent instability. At final follow-up, 9 of 12 (75%) patients indicated that their sports participation levels were equal to their preinjury levels. Median patient satisfaction at final follow-up was 10 of 10 points (range, 3-10).

The arthroscopic BBB technique for patients with anterior bony Bankart lesions can restore shoulder stability, yield durable improvements in clinical outcomes, and provide a high return-to-sport rate at a minimum 5-year follow-up. Three of 13 patients experienced postoperative symptoms of instability but did not undergo further stabilization surgery.

There is a lack of knowledge about the changes in perianchor cysts over time and the factors related to perianchor cysts.

To evaluate the changes in perianchor cyst formation and anchor absorption over time after arthroscopic rotator cuff repair with a biocomposite suture anchor and to evaluate the factors affecting perianchor cyst persistence and their relationship with patient outcomes.

Case-control study; Level of evidence, 3.

Forty consecutive patients (mean age, 61.10 ± 5.79 years) who underwent arthroscopic repair for medium- to large-sized rotator cuff tears using a single type of biocomposite (poly-L-lactic acid/polyglycolic acid–beta tricalcium phosphate) medial-row anchor were prospectively enrolled. Postoperative magnetic resonance imaging (MRI) at 2 different time points (6 and 18 months) was performed, and perianchor cyst formation, anchor absorption, and healing failures were evaluated using postoperative MRI. Demographic and clinical data were collected, and functional outcomes at a minimum of 18 months after surgery were assessed.

Perianchor cysts were observed in 24 patients (60.0% total; grade 1: 35.0%; grade 2: 10.0%; grade 3: 7.5%; grade 4: 7.5%) at 6 months, and 7 patients (18.4% total; grade 1: 7.9%; grade 2: 5.3%; grade 3: 2.6%; grade 4: 2.6%) had a persistent perianchor cyst at 18 months after surgery. No anchors were absorbed at 6 months, but 73.7% of patients revealed complete or near-full absorption at 18 months. Patients with persistent perianchor cysts showed a significantly larger tear size in the anteroposterior dimension (P = .002) and greater retraction (P < .001). There were no differences in healing failures and functional outcomes between patients with and without persisting perianchor cysts (all P > .05). No differences were found in perianchor cyst formation and anchor absorption between anchors inserted in the greater tuberosity and the lesser tuberosity (all P > .05).

The incidence and severity of perianchor cysts decreased with time, and most biocomposite suture anchors were absorbed at 18 months after surgery. Persisting perianchor cysts correlated with a larger tear size in the anteroposterior dimension and greater retraction.

Scoring systems integrating possible prognostic factors and predicting rotator cuff healing after surgical repair could provide valuable information for clinical practice.

To determine the prognostic factors predictive of rotator cuff healing after surgical repair and to integrate these factors into a scoring system.

Case-control study; Level of evidence, 3.

The authors reviewed the records of 603 patients who, at least 12 months after primary rotator cuff repair by a single surgeon, had magnetic resonance imaging or computed tomographic arthrography to assess repair integrity. The mean age at the time of surgery was 60 years (range, 39-81 years), and 378 patients were women (62.7%). Previous known or suggested factors affecting cuff integrity were analyzed through univariate and multivariate analyses. Factors identified in the multivariate analysis were integrated in a scoring system based on odds ratios (ORs).

The overall healing failure rate was 24%. The following independent risk factors were identified in the multivariate analysis: age >70 years at the time of surgery (P = .003, OR = 2.71), size of the tear in anteroposterior dimension (P = .033, OR = 1.94) and retraction (P = .000, OR = 4.56), fatty infiltration of infraspinatus exceeding grade 2 (P = .001, OR = 2.91), low bone mineral density (T score ≤ –2.5, P = .04, OR = 1.95), and high level of work activity (P = .036, OR = 2.18). A 15-point scoring system comprised the following: 4 points for retraction; 3 points for fatty infiltration of infraspinatus; and 2 points for anteroposterior tear size, age, bone mineral density, and work activity, weighted according to multivariate analysis ORs. Patients with ≤4 points had a 6.0% healing failure rate, and those with ≥5 and ≥10 points had 55.2% and 86.2% healing failure rates, respectively.

A numerical scoring system including significant clinical and radiological factors was designed to predict healing of the rotator cuff after surgical repair. This scoring system helped predict the adequacy of the repair and assist in deciding the appropriate treatment options.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Global-10 was recently developed to assess physical and mental health and provide an estimated EuroQol-5 Dimension (EQ-5D) score. This instrument needs to be validated for specific patient cohorts such as those with rotator cuff pathology.

There is moderate to high correlation between the PROMIS Global-10 and legacy patient-reported outcome measures; PROMIS Global-10 will not show ceiling effects; and estimated EQ-5D scores will show good correlation and low variance with actual EQ-5D scores.

Cohort study (diagnosis); Level of evidence, 2.

A total of 323 patients with rotator cuff disease were prospectively enrolled before treatment. Each patient completed the PROMIS Global-10, EQ-5D, American Shoulder and Elbow Surgeons (ASES) shoulder assessment form, and Single Assessment Numeric Evaluation (SANE), and those with known rotator cuff tears completed the Western Ontario Rotator Cuff Index (WORC). Spearman correlations were calculated. Bland-Altman agreement tests were conducted between estimated EQ-5D scores from the PROMIS and actual EQ-5D scores. Ceiling and floor effects were assessed, defined as ≥15% respondents with highest or lowest possible score.

Correlation between the PROMIS Global-10 and EQ-5D was excellent (0.70, P < .0001). Correlation of the PROMIS physical scores was excellent-good with the ASES (0.62, P < .0001), good with the WORC (0.47, P < .0001), and good with the SANE (0.41, P < .0005). Correlation between the PROMIS mental scores was poor with the ASES (0.34, P < .0001), the WORC (0.32, P = .0016), and the SANE (0.24, P < .0001). No floor or ceiling effects were found. Agreement analysis showed substantial variance in individual scores, despite the overall similarity in mean scores between the estimated and actual EQ-5D scores, indicating poor agreement. Bland-Altman 95% limits of agreement for estimated EQ-5D scores ranged from 34% below to 31% above actual EQ-5D scores.

Physical function scores of the PROMIS Global-10 show high correlation with legacy patient-reported outcome instruments, suggesting that it is a reliable tool for outcome assessment in a population with rotator cuff pathology. The large variability in 95% limit of agreement suggested that the estimated EQ-5D scores from the PROMIS Global-10 cannot replace traditional EQ-5D scores.

Biomechanical studies have shown that synthetic turf surfaces do not release cleats as readily as natural turf, and it has been hypothesized that concomitant increased loading on the foot contributes to the incidence of lower body injuries.

This study evaluates this hypothesis from an epidemiologic perspective, examining whether the lower extremity injury rate in National Football League (NFL) games is greater on contemporary synthetic turfs as compared with natural surfaces.

Incidence of lower body injury is higher on synthetic turf than on natural turf among elite NFL athletes playing on modern-generation surfaces.

Cohort study; Level of evidence, 3.

Lower extremity injuries reported during 2012-2016 regular season games were included, with all 32 NFL teams reporting injuries under mandated, consistent data collection guidelines. Poisson models were used to construct crude and adjusted incidence rate ratios (IRRs) to estimate the influence of surface type on lower body injury groupings (all lower extremity, knee, ankle/foot) for any injury reported as causing a player to miss football participation as well as injuries resulting in ≥8 days missed. A secondary analysis was performed on noncontact/surface contact injuries.

Play on synthetic turf resulted in a 16% increase in lower extremity injuries per play than that on natural turf (IRR, 1.16; 95% CI, 1.10-1.23). This association between synthetic turf and injury remained when injuries were restricted to those that resulted in ≥8 days missed, as well as when categorizations were narrowed to focus on distal injuries anatomically closer to the playing surface (knee, ankle/foot). The higher rate of injury on synthetic turf was notably stronger when injuries were restricted to noncontact/surface contact injuries (IRRs, 1.20-2.03; all statistically significant).

These results support the biomechanical mechanism hypothesized and add confidence to the conclusion that synthetic turf surfaces have a causal impact on lower extremity injury.

Concussion is one of the most common sports-related injuries, with little understood about the modifiable and nonmodifiable risk factors. Researchers have yet to evaluate the association between modifiable sensorimotor function variables and concussive injury.

To investigate the association between dynamic balance performance, a discrete measure of sensorimotor function, and concussive injuries.

Cohort study (diagnosis); Level of evidence, 3.

A total of 109 elite male rugby union players were baseline tested in dynamic balance performance while wearing an inertial sensor and prospectively followed during the 2016-2017 rugby union season. The sample entropy of the inertial sensor gyroscope magnitude signal was derived to provide a discrete measure of dynamic balance performance. Logistic regression modeling was then used to investigate the association among the novel digital biomarker of balance performance, known risk factors of concussion (concussion history, age, and playing position), and subsequent concussive injury.

Participant demographic data (mean ± SD) were as follows: age, 22.6 ± 3.6 years; height, 185 ± 6.5 cm; weight, 98.9 ± 12.5 kg; body mass index, 28.9 ± 2.9 kg/m²; and leg length, 98.8 ± 5.5 cm. Of the 109 players, 44 (40.3%) had a history of concussion, while 21 (19.3%) sustained a concussion during the follow-up period. The receiver operating characteristic analysis for the anterior sample entropy demonstrated a statistically significant area under the curve (0.64; 95% CI, 0.52-0.76; P < .05), with the cutoff score of anterior sample entropy ≥1.2, which maximized the sensitivity (76.2%) and specificity (53.4%) for identifying individuals who subsequently sustained a concussion. Players with suboptimal balance performance at baseline were at a 2.81-greater odds (95% CI, 1.02-7.74) of sustaining a concussion during the rugby union season than were those with optimal balance performance, even when controlling for concussion history.

Rugby union players who possess poorer dynamic balance performance, as measured by a wearable inertial sensor during the Y balance test, have a 3-times-higher relative risk of sustaining a sports-related concussion, even when controlling for history of concussion. These findings have important implications for research and clinical practice, as it identifies a potential modifiable risk factor. Further research is required to investigate this association in a large cohort consisting of males and females across a range of sports.

The citation rate of a research published article is an indicator of its quality and impact and contributes to the journal’s impact factor. Within the orthopaedic sports medicine literature, predictors of citation rates have not been previously described.

To identify characteristics of published articles that predict 5-year citation rates of studies in the orthopaedic sports medicine literature.

Cross-sectional study.

Research articles published in The American Journal of Sports Medicine (AJSM), Arthroscopy: The Journal of Arthroscopic and Related Surgery, and Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) from 2012 were analyzed. Extracted characteristics of published articles included journal, author number, origin of study, first author degree, subject of study, study type, sample size, number of references and institutions, conflicts of interest, level of evidence, and 5-year citation rates. Multivariate logistic regression was used to determine predictors of greater than the mean number of citations at 5 years.

A total of 825 published articles (AJSM, n = 313; Arthroscopy, n = 173; KSSTA, n = 339) were included in the final analysis. The mean number of 5-year citations was 23.2 (95% CI, 21.6-24.9; range, 1.0-260.0). AJSM had a significantly greater citation rate (32.4) than Arthroscopy (21.7) and KSSTA (15.2) (P < .001 for both). Arthroscopy had a greater citation rate than KSSTA (P = .008). Independent predictors of greater than the mean number of citations at 5 years were published articles in AJSM (odds ratio [OR], 5.17; 95% CI, 2.81-9.52; P < .0001), published articles of North American origin (OR, 1.79; 95% CI, 1.25-2.58; P = .002), and published articles regarding the hip (OR, 2.68; 95% CI, 1.08-6.67; P = .035).

Published articles in AJSM, those from North America, and those examining the hip were independent predictors of greater citation rates at 5 years.

In this study, we investigate the in vitro and in vivo chondrogenic capacity of a novel photopolymerizable cartilage mimetic hydrogel, enhanced with extracellular matrix analogs, for cartilage regeneration.

To (1) determine whether mesenchymal stem cells (MSCs) embedded in a novel cartilage mimetic hydrogel support in vitro chondrogenesis, (2) demonstrate that the proposed hydrogel can be delivered in situ in a critical chondral defect in a rabbit model, and (3) determine whether the hydrogel with or without MSCs supports in vivo chondrogenesis in a critical chondral defect.

Controlled laboratory study.

Rabbit bone marrow–derived MSCs were isolated, expanded, encapsulated in the hydrogel, and cultured in chondrogenic differentiation medium for 9 weeks. Compressive modulus was evaluated at day 1 and at weeks 3, 6, and 9. Chondrogenic differentiation was investigated via quantitative polymerase reaction, safranin-O staining, and immunofluorescence. In vivo, a 3 mm–wide × 2-mm-deep chondral defect was created bilaterally on the knee trochlea of 10 rabbits. Each animal had 1 defect randomly assigned to be treated with hydrogel with or without MSCs, and the contralateral knee was left untreated. Hence, each rabbit served as its own matched control. Three groups were established: group A, hydrogel (n = 5); group B, hydrogel with MSCs (n = 5); and group C, control (n = 10). Repair tissue was evaluated at 6 months after intervention.

In vitro, chondrogenesis and the degradable behavior of the hydrogel by MSCs were confirmed. In vivo, the hydrogel could be delivered intraoperatively in a sterile manner. Overall, the hydrogel group had the highest scores on the modified O’Driscoll scoring system (group A, 17.4 ± 4.7; group B, 13 ± 3; group C, 16.7 ± 2.9) (P = .11) and showed higher safranin-O staining (group A, 49.4% ± 20%; group B, 25.8% ± 16.4%; group C, 36.9% ± 25.2%) (P = .27), although significance was not detected for either parameter.

This study provides the first evidence of the ability to photopolymerize this novel hydrogel in situ and assess its ability to provide chondrogenic cues for cartilage repair in a small animal model. In vitro chondrogenesis was evident when MSCs were encapsulated in the hydrogel.

Cartilage mimetic hydrogel may offer a tissue engineering approach for the treatment of osteochondral lesions.

The addition of a type I/III collagen membrane in cartilage defects treated with microfracture has been advocated for cartilage repair, termed “autologous matrix-induced chondrogenesis” (AMIC).

To examine the current clinical evidence regarding AMIC for focal chondral defects.

Systematic review.

A systematic review was performed by searching PubMed, ScienceDirect, and Cochrane Library databases. Inclusion criteria were clinical studies of AMIC for articular cartilage repair, written in English. Relative data were extracted and critically analyzed. PRISMA guidelines were applied, the methodological quality of the included studies was assessed by the modified Coleman Methodology Score (CMS), and aggregate data were generated.

Twenty-eight clinical articles were included: 12 studies (245 patients) of knee cartilage defects, 12 studies (214 patients) of ankle cartilage defects, and 4 studies (308 patients) of hip cartilage defects. The CMS demonstrated a suboptimal study design in the majority of published studies (knee, 57.8; ankle, 55.3; hip, 57.7). For the knee, 1 study reported significant clinical improvements for AMIC compared with microfracture for medium-sized cartilage defects (mean defect size 3.6 cm²) after 5 years (level of evidence, 1). No study compared AMIC with matrix-assisted autologous chondrocyte implantation (ACI) in the knee. For the ankle, no clinical trial was available comparing AMIC versus microfracture or ACI. In the hip, only one analysis (level of evidence, 3) compared AMIC with microfracture for acetabular lesions. For medium-sized acetabular defects, one study (level of evidence, 3) found no significant differences between AMIC and ACI at 5 years. Specific aspects not appropriately discussed in the currently available literature include patient-related factors, membrane fixation, and defect properties. No treatment-related adverse events were reported.

This systematic review reveals a paucity of high-quality, randomized controlled studies testing the AMIC technique versus established procedures such as microfracture or ACI. Evidence is insufficient to recommend joint-specific indications for AMIC. Additional nonbiased, high-powered, randomized controlled clinical trials will provide better clinical and structural long-term evidence, thus helping to define possible indications for this technique.

Although most anterior tibial stress fractures heal with nonoperative treatment, some may require surgical management. To our knowledge, no systematic review has been conducted regarding surgical treatment strategies for the management of chronic anterior tibial stress fractures from which general conclusions can be drawn regarding optimal treatment in high-performance athletes.

This systematic review was conducted to evaluate the surgical outcomes of anterior tibial stress fractures in high-performance athletes.

Systematic review; Level of evidence, 4.

In February 2017, a systematic review of the PubMed, MEDLINE, Cochrane, SPORTDiscus, and CINAHL databases was performed to identify studies that reported surgical outcomes for anterior tibial stress fractures. Articles meeting the inclusion criteria were screened, and reported outcome measures were documented.

A total of 12 studies, published between 1984 and 2015, reporting outcomes for the surgical treatment of anterior tibial stress fractures were included in this review. All studies were retrospective case series. Collectively, surgical outcomes for 115 patients (74 males; 41 females) with 123 fractures were evaluated in this review. The overall mean follow-up was 23.3 months. The most common surgical treatment method reported in the literature was compression plating (n = 52) followed by drilling (n = 33). Symptom resolution was achieved in 108 of 123 surgically treated fractures (87.8%). There were 32 reports of complications, resulting in an overall complication rate of 27.8%. Subsequent tibial fractures were reported in 8 patients (7.0%). Moreover, a total of 17 patients (14.8%) underwent a subsequent procedure after their initial surgery. Following surgical treatment for anterior tibial stress fracture, 94.7% of patients were able to return to sports.

The available literature indicates that surgical treatment of anterior tibial stress fractures is associated with a high rate of symptom resolution and return to play in athletes, although the high complication rate and potential need for subsequent procedures are important considerations for surgeons and patients.

Given the high number of available patient-reported outcome (PRO) tools for patients undergoing shoulder surgery, comparative information is necessary to determine the most relevant forms to incorporate into clinical practice.

To determine the utilization and responsiveness of common PRO tools in studies involving patients undergoing arthroscopic rotator cuff repair or operative management of glenohumeral instability.

Systematic review.

A systematic review of rotator cuff and instability studies from multiple databases was performed according to PRISMA guidelines. Means and SDs of each PRO tool utilized, study sample sizes, and follow-up durations were collected. The responsiveness of each PRO tool compared with other PRO tools was determined by calculating the effect size and relative efficiency (RE).

After a full-text review of 238 rotator cuff articles and 110 instability articles, 81 studies and 29 studies met the criteria for final inclusion, respectively. In the rotator cuff studies, 25 different PRO tools were utilized. The most commonly utilized PRO tools were the Constant (50 studies), visual analog scale (VAS) for pain (44 studies), American Shoulder and Elbow Surgeons (ASES; 39 studies), University of California, Los Angeles (UCLA; 20 studies), and Disabilities of the Arm, Shoulder and Hand (DASH; 13 studies) scores. The ASES score was found to be more responsive than all scores including the Constant (RE, 1.94), VAS for pain (RE, 1.54), UCLA (RE, 1.46), and DASH (RE, 1.35) scores. In the instability studies, 16 different PRO tools were utilized. The most commonly used PRO tools were the ASES (13 studies), Rowe (10 studies), Western Ontario Shoulder Instability Index (WOSI; 8 studies), VAS for pain (7 studies), UCLA (7 studies), and Constant (6 studies) scores. The Rowe score was much more responsive than both the ASES (RE, 22.84) and the Constant (RE, 33.17) scores; however, the ASES score remained more responsive than the Constant (RE, 1.93), VAS for pain (RE, 1.75), and WOSI (RE, 0.97) scores.

Despite being frequently used in the research community, the Constant score may be less clinically useful as it was less responsive. Additionally, it is a greater burden on the provider because it requires objective strength and range of motion data to be gathered by the clinician. In contrast, the ASES score was highly responsive after rotator cuff repair and requires only subjective patient input. Furthermore, separate PRO scoring methods appear to be necessary for patients undergoing rotator cuff repair and surgery for instability as the instability-specific Rowe score was much more responsive than the ASES score.