The American Journal of Sports Medicine

Arthroscopic rotator cuff repair (ARCR) is one of the most commonly performed orthopaedic surgical procedures; however, patient-reported outcomes have varied greatly in the literature.

To identify preoperative factors that affect outcomes and to develop prognostic tools for predicting functional outcomes in future ARCR cases.

Cohort study; Level of evidence, 3.

Patients were included who underwent ARCR for repairable full-thickness rotator cuff tears with at least 2 years of follow-up. Twelve predictors were entered as candidate predictors in each model: age, sex, workers’ compensation (WC) status, previous cuff repair, tear size, tear shape, multiple-tendon involvement, tendon stump length, Goutallier classification, critical shoulder angle, length of follow-up, and baseline subjective outcomes score. Postoperative American Shoulder and Elbow Surgeons (ASES), 12-Item Short Form Health Survey Physical Component Summary (SF-12 PCS), QuickDASH (short version of Disabilities of the Arm, Shoulder and Hand), and patient satisfaction were each modeled through proportional odds ordinal logistic regression. Model results were presented with marginal covariate effect plots and predictive nomograms.

Overall, 552 shoulders fit inclusion criteria. The mean age at surgery was 60.2 years (range, 23-81 years). Twenty-five (4.5%) shoulders underwent revision cuff repair or reverse arthroplasty at a mean 1.9 years (range, 0.1-7.9 years) postoperatively. Overall, 509 shoulders were eligible for follow-up, and minimum 2-year postoperative patient-reported outcomes were obtained for 449 (88.2%) at a mean 4.8 years (range, 2-11 years). The ASES score demonstrated significant improvement from pre- to postoperative median (interquartile range): 58 (44.9-71.6) to 98.3 (89.9-100; P < .001). Women demonstrated significantly higher 2-year reoperation rates than men (5.8% vs 1.6%; odds ratio, 2.8 [95% CI, 0.73-9.6]; P = .023). Independently significant predictors for lower postoperative ASES scores included previous ARCR (P < .001), female sex (P < .001), and a WC claim (P < .001). Significant predictors for worse QuickDASH scores included WC claim (P < .001), female sex (P < .001), previous ARCR (P = .007), and ≥7 years of follow-up time. Significant predictors for lower SF-12 PCS scores included WC claim (P < .001), female sex (P = .001), and lower baseline SF-12 PCS. Last, significant independent predictors of patient satisfaction included previous ARCR (P = .004), WC claim (P = .011), female sex (P = .041), and age (P = .041).

Excellent clinical outcomes and low failure rates were obtained after ARCR by using careful patient selection and modern surgical techniques for ARCR. Female sex, WC claim, and previous ARCR were significant predictors of poorer outcomes in at least 3 patient-reported outcome models. Prognostic nomograms were developed to aid in future patient selection, clinical decision making, and patient education.

Arthroscopic rotator cuff repair (RCR) with suture anchor–based fixation techniques has replaced former open and mini-open approaches. Nevertheless, long-term studies are scarce, and lack of knowledge exists about whether single-row (SR) or double-row (DR) methods are superior in clinical and anatomic results.

To analyze long-term results after arthroscopic RCR in patients with symptomatic rotator cuff tears and to compare functional and radiographic outcomes between SR and DR repair techniques at least 10 years after surgery.

Cohort study; Level of evidence, 3.

Between 2005 and 2006, 40 patients with a symptomatic full-thickness rotator cuff tear (supraspinatus tendon tear with or without a tear of the infraspinatus tendon) underwent arthroscopic RCR with either an SR repair with a modified Mason-Allen suture–grasping technique (n = 20) or a DR repair with a suture bridge fixation technique (n = 20). All patients were enrolled in a long-term clinical evaluation, with the Constant score (CS) as the primary outcome measure. Furthermore, an ultrasound examination was performed to assess tendon integrity and conventional radiographs to evaluate secondary glenohumeral osteoarthritis.

A total of 27 patients, of whom 16 were treated with an SR repair and 11 with a DR repair, were followed up after a mean ± SD period of 12 ± 1 years (range, 11-14 years). Five patients underwent revision surgery on the affected shoulder during follow-up period, which led to 22 patients being included. The overall CS remained stable at final follow-up when compared with short-term follow-up (81 ± 8 vs 83 ± 19 points; P = .600). An increasing number of full-thickness retears were found: 6 of 22 (27%) at 2 years and 9 of 20 (45%) at 12 years after surgery. While repair failure negatively affected clinical results as shown by the CS (P < .05), no significant difference was found between the fixation techniques (P = .456). In general, progressive osteoarthritic changes were observed, with tendon integrity as a key determinant.

Arthroscopic RCR with either an SR or a DR fixation technique provided good clinical long-term results. Repair failure was high, with negative effects on clinical results and the progression of secondary glenohumeral osteoarthritis. While DR repair slightly enhanced tendon integrity at long-term follow-up, no clinical superiority to SR repair was found.

Dog-ear and bird-beak deformities are common after transosseous-equivalent repair (suture bridge technique). The natural course of deformities after rotator cuff (RC) repair using the suture bridge technique is unclear. The remodeling potential of these deformities has not been investigated.

To evaluate remodeling and retear rates associated with deformities after RC repair.

Cohort study; Level of evidence, 3.

Between November 2011 and February 2012, we studied 99 consecutive shoulders. All patients underwent arthroscopic RC repair via the suture bridge technique with or without additional sutures. Two groups were formed: no deformity (n= 46) and deformity (n = 53). Deformity was defined as marginal detachment and protrusion of the RC after repair, involving inappropriate compression of the suture limbs from the anchors. Tendon height was measured from the highest point of the most protruding portion of the cuff to the cortex on semi-coronal magnetic resonance imaging (MRI) scan. Change in tendon height was evaluated on MRI scan at 1 week and 6 months postoperatively. Clinical assessment at every patient visit included the American Shoulder and Elbow Surgeons (ASES) score, Constant shoulder score, and visual analog scale for pain (pVAS) score.

No significant differences were found in age, sex, symptom duration, tear size, and preoperative ASES, Constant, and pVAS scores (P > .05) between the 2 groups. The initial tendon height was 7.4 ± 1.5 mm in the no-deformity group and 9.3 ± 2.0 mm in the deformity group. Follow-up height was 6.3 ± 2.1 mm in the no-deformity group and 6.4 ± 1.6 mm in the deformity group. Mean postoperative tendon heights were 90.1% ± 23.8% of the initial height in the no-deformity group and 73.2% ± 15.1% in the deformity group. Clinical scores (ASES, Constant, and pVAS) were not significantly different between the groups at 6 months. There were 4 shoulders in each group that experienced retearing (types 4 and 5 according to the Sugaya classification) at 6 months postoperatively. There was no difference in retear rate (P > .999).

Most deformities after RC repair were remodeled with no effect on retears. Clinical outcomes were not affected by deformities.

Recent evidence has specified indications for performing superior labral anterior posterior (SLAP) repair and biceps tenodesis (BT) for the treatment of bicipital-labral lesions in the shoulder. Trends in performance of these procedures are expected to reflect the growing body of research regarding this topic.

To report practice trends for the surgical treatment of SLAP lesions utilizing the American Board of Orthopaedic Surgery (ABOS) database, particularly in older patients.

Cohort study; Level of evidence, 3.

The ABOS database was retrospectively queried between 2012 and 2017 by Current Procedural Terminology (CPT) codes for SLAP repair (29807), open BT (23430), and arthroscopic BT (29828). The patient population was excluded if any concomitant open shoulder procedure was performed. Trends over time were evaluated with respect to case volume, patient age, surgeon subspecialty, and whether a concomitant arthroscopic rotator cuff repair (RCR) was performed (CPT 29827).

A total of 9908 cases met inclusion/exclusion criteria: 4632 performed with RCR and 5276 performed without. The mean age of patients without RCR was 40.8 ± 13.8 years, while for those receiving RCR it was 55.0 ± 9.9 years (P < .001). In patients without RCR, there was a significant decline in rate of SLAP repairs performed over this period (P < .001). A significantly greater proportion of patients receiving open and arthroscopic BT were older than 35 years of age, compared with those receiving SLAP repair (P < .001). Within the RCR cohort, there was also a significant decline in concomitant SLAP repairs performed (P < .001) over the study period. With respect to BT, open BT was performed more frequently in the cohort without RCR (74.5%) than in the cohort with RCR (52.1%) (P < .001). Similarly, arthroscopic BT was performed more commonly in the cohort with RCR (47.9%) than in the cohort without RCR (25.5%) (P < .001).

The ABOS database revealed significantly reduced rates of SLAP repairs performed in recent times. Trends with age remained consistent over time, in that SLAP repairs were predominantly performed in younger patients. Open BT was performed more frequently overall, but with an increased proportion of arthroscopic BT occurring with RCR. Arthroscopic BT was performed much more frequently with RCR than without.

Successful repair of large and massive rotator cuff (RC) tears remains a challenge at least partially because of secondary muscle atrophy and fatty infiltration. β3 Adrenergic agonists are a group of drugs that promote fat resorption through “white fat browning” of intramuscular stem cells.

To test the role of a β3 adrenergic receptor agonist, amibegron, in improving muscle quality and forelimb function in a delayed RC repair model via promoting brown/beige adipose tissue activation.

Controlled laboratory study.

Three-month-old PDGFRα-GFP reporter mice, wild type C57BL/6J mice, and uncoupling protein 1 (UCP-1) knockout mice underwent unilateral supraspinatus tendon transection with a 6-week delayed tendon repair. Animals with sham surgery served as controls. Amibegron was given either immediately after tendon transection or after repair. Gait analysis was conducted to measure forelimb function at 6 weeks after tendon repair. Animals were sacrificed at 6 weeks after repair. Supraspinatus muscles were harvested and analyzed histologically. Reverse transcription polymerase chain reaction was performed to quantify gene expression related to atrophy, fibrosis, and fatty infiltration.

Histology of PDGFRα reporter mice showed significantly increased UCP-1 expression, suggesting white fat browning in muscle after RC repair. As administered either immediately after tendon transection or after tendon repair, amibegron significantly reduced muscle atrophy and fatty infiltration and resumed normal upper extremity gait in wild type mice. However, the effect of amibegron was not present in UCP-1 knockout mice, suggesting that the effect of amibegron in treating RC muscle atrophy and fatty infiltration is through a UCP 1–dependent mechanism.

Amibegron reduced muscle atrophy and fatty infiltration and improved forelimb function after delayed RC repair through a UCP 1–dependent mechanism. This may be an effective clinical treatment strategy for patients to improve muscle quality after RC repair.

β3 Adrenergic agonists may serve as a new pharmacologic modality to treat RC muscle atrophy and fatty infiltration to improve clinical outcome of RC repair.

Pitch velocity is associated with elbow injuries among skillful baseball players. However, the relationship between pitch velocity and throwing elbow injuries among youth players has not yet been clarified.

To investigate the influence of pitch velocity on medial elbow pain and medial epicondyle abnormality among youth baseball players.

Cohort study; Level of evidence, 3.

The participants consisted of 256 elementary school players (mean age, 11 ± 1 years; range, 9-12 years). The medial aspect of the elbow was evaluated using ultrasound imaging. A questionnaire was used to investigate past or present pain in the elbow, background of the players (age, height, body mass index, and years of baseball experience), and playing environment (number of days of practice in a week, experience as a pitcher, and cryotherapy of the shoulder and elbow after practice). Positioning of the scapula, range of motion in shoulder internal/external rotations and hip internal rotation, angle of the straight-leg raise, and heel-to-buttock distance were measured. The pitch velocity was recorded using a pitch velocity radar gun. The relationship between these variables and the presence of medial epicondyle abnormality, as well as past or present elbow pain, were statistically analyzed.

A medial epicondyle abnormality was observed in 130 players (51%), elbow pain in the past in 65 players (25%), and elbow pain during the examination in 14 players (5%). Sixty-nine players (27%) experienced elbow pain either in the past or during examination. Abnormality of the medial epicondyle had a relationship with the pitch velocity (odds ratio [OR], 1.1 for increase of 1 km/h; 95% CI, 1.1-1.2; P < .0001) and the number of practice days in a week (OR, 1.8 for increase of the practice days; 95% CI, 1.4-2.5; P < .0001). Pitch velocity was also significantly related with past pain, present pain, and past and/or present pain of the elbow (OR [km/h], 1.1, 1.1, 1.1; 95% CI, 1.0-1.1, 1.0-1.2, 1.1-1.2; P < .0001, P = .002, P < .0001, respectively).

Pitch velocity was significantly associated with abnormality of the medial epicondyle and elbow pain. A 10-km/h increase in pitch velocity would increase the risk of medial epicondyle abnormality and medial elbow pain by 3 times.

Hip arthroscopy has been previously demonstrated to be an effective treatment for adult mild hip dysplasia. There are many radiographic parameters used to classify hip dysplasia, but to date few studies have demonstrated which parameters are of most importance for predicting surgical outcomes.

To identify preoperative radiographic parameters that are associated with poor outcomes in the arthroscopic treatment of adult mild hip dysplasia.

Case-control study; Level of evidence, 3.

Radiographic analysis was performed in patients with mild hip dysplasia who underwent arthroscopic surgery between 2009 and 2015. Preoperative radiographic measurements included lateral center edge angle, Tönnis angle, neck shaft angle, anterior center edge angle, alpha angle, femoral head extrusion index, and acetabular depth-to-width ratio. Failure was defined as failure to achieve the minimal clinically important difference (MCID) utilizing the modified Harris Hip Score or as the need for secondary operation. The equal variance t test was used to analyze radiographic parameters. Statistical significance was determined using a P value of .05.

A total of 373 hips underwent analysis with an average follow-up of 41 months (range, 24-102 months). Of these, 46 hips (12%) required secondary operation, and 95 (25%) failed to meet the MCID. The overall failure rate was 32.4%. There was no single measurement or combination thereof associated with failure to reach the MCID. Higher preoperative Tönnis angles were associated with secondary operation, with a mean of 6.7° (95% CI, 5.3°-8.1°) in the secondary operation group versus 4.8° (95% CI, 4.4°-5.3°) in the nonsecondary operation group (P = .006). The odds ratio was 1.12 (95% CI, 1.0-1.2; P = .05) per degree increase in Tönnis angle for secondary operation. In patients with a Tönnis angle >10°, 84% required secondary operation.

Higher Tönnis angles portend a higher risk for revision surgery. The probability of secondary operation was increased by a magnitude of 1.12 with each degree increase in the Tönnis angle. In patients with a Tönnis angle >10°, 84% required a secondary operation.

Hip arthroscopy for the treatment of femoroacetabular impingement syndrome (FAIS) in patients with borderline hip dysplasia (BHD) is becoming a more common practice. However, the literature on achieving meaningful outcomes at midterm follow-up, as well as predictors of these outcomes, is limited.

To (1) compare the rates of achieving meaningful clinical outcomes between patients with and without BHD and (2) identify the predictors for achieving clinical success among patients with BHD 5 years after undergoing hip arthroscopic surgery for FAIS.

Cohort study; Level of evidence, 3.

Data from consecutive patients who underwent primary hip arthroscopic surgery with routine capsular closure for the treatment of FAIS between January 2012 and August 2014 were collected and retrospectively analyzed. Patients with BHD (lateral center-edge angle [LCEA] 20°-25°) were matched 1:2 by age (±1 year) and body mass index (BMI; ±5 kg/m²) to control patients with normal acetabular coverage (LCEA 25°-40°). Data collected included baseline and 5-year postoperative patient-reported outcomes. The minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) were calculated for each patient-reported outcome measure and compared between the 2 groups. A binary logistic regression analysis was used to identify significant predictors of achieving the MCID and PASS in the BHD group.

The MCID in the BHD group was defined as 9.6, 14.1, and 9.5 for the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, and modified Harris Hip Score, respectively. Threshold scores for achieving the PASS in both groups were 90.9, 76.6, and 81.9, respectively. A total of 88 patients were identified with having BHD and were matched to 176 controls. No statistical differences were identified for age, BMI, or sex. Both the BHD and the non-BHD groups had statistically significant increases in patient-reported outcome scores over the 5-year period, but the difference in both groups was not statistically significant (P > .05 for all). There was no statistical difference in the frequency of patients in the BHD and non-BHD groups achieving the MCID (86.6% vs 85.2%, respectively; P = .804) or PASS (76.0% vs 73.7%, respectively; P = .675) on at least 1 outcome measure. The logistic regression model demonstrated that being physically active (odds ratio [OR], 27.59; P = .005) and being female (OR, 14.64; P = .025) were independent predictors of achieving the MCID, while running (OR, 11.1; P = .002), being female (OR, 7.6; P = .011), and a larger preoperative LCEA (OR, 2.3; P = .001) were independent preoperative predictors of achieving the PASS.

The rates of achieving clinical success 5 years after undergoing arthroscopic treatment with capsular closure for FAIS were not significantly different between patients with BHD and those with normal acetabular coverage. Being physically active, running for exercise, female sex, and a larger LCEA were preoperative predictors of achieving clinical success at 5 years in patients with BHD.

Association among generalized ligamentous laxity (GLL), hip microinstability, and patient-reported outcomes (PROs) after hip arthroscopy has yet to be completely established.

(1) To report minimum 2-year PROs in patients with GLL who underwent hip arthroscopy in the setting of symptomatic labral tears and femoroacetabular impingement syndrome and (2) to compare clinical results with a matched-pair control group without GLL.

Cohort study; Level of evidence, 3.

Data from a prospectively collected database were retrospectively reviewed between August 2014 and December 2016. Patients were considered eligible if they received primary arthroscopic treatment for symptomatic labral tears and femoroacetabular impingement. Inclusion criteria included preoperative and minimum 2-year follow-up scores for the following PROs: modified Harris Hip Score (mHHS), Non-arthritic Hip Score (NAHS), and visual analog scale for pain (VAS). From the sample population, 2 groups were created: the GLL group (Beighton score ≥4) and the control group (Beighton score <4). Patients were matched in a 1:2 ratio via propensity score matching according to age, sex, body mass index, Tönnis grade, and preoperative lateral center-edge angle. Patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID) for mHHS, Hip Outcome Score–Sports Specific Scale (HOS-SSS), and International Hip Outcome Tool–12 (iHOT-12) were calculated.

A total of 57 patients with GLL were matched to 88 control patients. Age, sex, body mass index, and follow-up times were not different between groups (P > .05). Preoperative radiographic measurements demonstrated no difference between groups. Intraoperative findings and procedures between groups were similar except for capsular treatment, with the GLL group receiving a greater percentage of capsular plications (P = .04). At minimum 2-year follow-up, both groups showed significant improvement in PROs and VAS (P < .001). Furthermore, the postoperative PROs at minimum 2-year follow-up and the magnitude of improvement (delta value) were similar between groups for mHHS, NAHS, HOS-SSS, and VAS (P > .05). Moreover, groups reached comparable rates of MCID and PASS for mHHS, HOS-SSS, and iHOT-12.

Patients with GLL after hip arthroscopy for symptomatic femoroacetabular impingement and labral tears may expect favorable outcomes with appropriate labral and capsular management at minimum 2-year follow-up. When compared with a pair-matched control group without GLL, results were comparable for mHHS, NAHS, HOS-SSS, and VAS and reached PASS and/or MCID for mHHS, HOS-SSS, and iHOT-12.

Different options, from reverse (anteverting) periacetabular osteotomy to hip arthroscopy, have been proposed for surgical treatment of femoroacetabular impingement syndrome (FAIS) in the setting of acetabular retroversion.

(1) To report and analyze midterm patient-reported outcome scores (PROs) in patients with FAIS and labral tears in the setting of acetabular retroversion after isolated hip arthroscopy and (2) to compare these PROs with those of a propensity-matched control group without acetabular retroversion.

Cohort study; Level of evidence, 3.

Prospectively collected data were retrospectively reviewed for patients who underwent hip arthroscopy for FAIS and labral tear treatment between June 2008 and March 2014. Inclusion criteria were as follows: acetabular retroversion, pre- and postoperative PROs for modified Harris Hip Score (mHHS), Non-arthritic Hip Score, Hip Outcome Score–Sports Specific Scale (HOS-SSS), and visual analog scale (VAS). Propensity score matching was utilized to identify a control group without acetabular retroversion matched 1:1 with similar age, sex, body mass index, acetabular and femoral head Outerbridge grade, preoperative lateral center-edge angle, and labral treatment. Patient acceptable symptomatic state (PASS) and/or minimal clinically important difference (MCID) for the mHHS, HOS-SSS, International Hip Outcome Tool–12, and VAS was calculated.

A total of 205 hips with acetabular retroversion were matched to a control group. The groups showed no difference in demographic variables. The retroversion group was composed of 139 female and 66 male hips, with a mean ± SD age of 23.81 ± 7.28 years and follow-up time of 65.24 ± 20.31 months. Intraoperative diagnostic data and procedures performed were similar between groups, except more femoroplasties were performed in the retroversion group. Significant improvements for the mHHS, Non-arthritic Hip Score, HOS-SSS, and VAS were seen for both groups at a mean 5-year follow-up. The proportion of patients who reached the PASS and MCID were similar.

In the setting of FAIS and labral tears, patients with acetabular retroversion can be safely treated with advanced hip arthroscopic techniques without reverse (anteverting) periacetabular osteotomy in a high-volume surgeon’s hands. Patients with acetabular retroversion demonstrated favorable PROs at midterm follow-up. Furthermore, the proportion of patients reaching the MCID and PASS for several PROs were comparable with those of a propensity-matched control group without acetabular retroversion.

Femoroacetabular impingement (FAI) has been proposed as an etiologic factor in up to 50% of hips with osteoarthritis (OA). Inflammation is thought to be one of the main initiators of OA, yet little is known about the origin of intra-articular inflammation in FAI hips.

Articular cartilage from the impingement zone of patients with FAI has high levels of inflammation, reflecting initial inflammatory process in the hip.

Controlled laboratory study.

Head-neck cartilage samples were obtained from patients with cam FAI (cam FAI, early FAI; n = 15), advanced OA secondary to cam FAI (FAI OA, late FAI; n = 15), and advanced OA secondary to developmental dysplasia of the hip (DDH OA, no impingement; n = 15). Cartilage procured from young adult donors (n = 7) served as control. Safranin O–stained sections were assessed for cartilage abnormality. Tissue viability was detected by TUNEL assay. Immunostaining of interleukin 1β (IL-1β), catabolic markers (matrix metalloproteinase 13 [MMP-13], a disintegrin and metalloproteinase with thrombospondin motif 4 [ADAMTS-4], aggrecan antibody to C-terminal neoepitope [NITEGE]), and an anabolic marker (type II collagen [COL2]) was performed to evaluate molecular inflammation and metabolic activity. The average percentage of immunopositive cells from the total cell count was calculated. Kruskal-Wallis test followed by Steel-Dwass post hoc test was used for multiple comparisons.

Microscopic osteoarthritic changes were more prevalent in cartilage of cam FAI and FAI OA groups compared with DDH OA and control groups. Cartilage in cam FAI and FAI OA groups, versus the DDH group, had higher expression of inflammatory molecules IL-1β (69.7% ± 18.1% and 72.5% ± 13.2% vs 32.7% ± 14.4%, respectively), MMP-13 (79.6% ± 12.6% and 71.4% ± 18.8% vs 38. 5% ± 13.3%), ADAMTS-4 (83.9% ± 12.2% and 82.6% ± 12.5% vs 45.7% ± 15.5%), and COL2 (93.6% ± 3.9% and 92.5% ± 5.8% vs 53.3% ± 21.0%) (P < .001). Expression of NITEGE was similar among groups (cam FAI, 89.7% ± 7.7%; FAI OA, 95.7% ± 4.7%; DDH OA, 93.9% ± 5.2%; P = .0742). The control group had minimal expression of inflammatory markers. Inflammatory markers were expressed in all cartilage zones of early and late FAI but only in the superficial zone of the no impingement group.

Cartilage from the impingement zone in FAI is associated with a high expression of inflammatory markers, extending throughout all cartilage zones.

Inflammation associated with FAI likely has a deleterious effect on joint homeostasis. Further clinical and translational studies are warranted to assess whether and how surgical treatment of FAI reduces molecular inflammation.

Anterior cruciate ligament (ACL) tears can either be treated nonoperatively with physical therapy and then treated operatively if persistent instability is present, or be directly treated operatively. Advantages of early ACL reconstruction surgery include shorter time from injury to surgery and potentially fewer meniscal injuries, but performing early ACL reconstruction in all patients results in surgery in patients who might not need ACL reconstruction. It is important to assess in which patients nonoperative treatment is successful and which patients will require ACL reconstruction and thus might be better treated surgically in an earlier phase.

To identify patient characteristics that predict the success of nonoperative treatment.

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

All patients with complete ACL injuries who were evaluated between 2014 and 2017 at our clinic were included. The minimum follow-up was 2 years. The initial treatment and ultimate ACL reconstruction were reviewed. Univariate analysis was performed using Mann-Whitney U tests and chi-square tests and multivariate analysis using binary logistic regression.

A total of 448 patients were included with a median age of 26 years and median Tegner level of 7 and mean Tegner level of 6.4. At initial consultation, 210 patients (47%) were treated nonoperatively with physical therapy and 126 of these patients (60%) ultimately required ACL reconstruction. Nonoperative treatment failed in 88.9% of patients <25 years of age, 56.0% of patients 25 to 40 years, and 32.9% of patients >40 years (P < .001); and 41.9% of patients with Tegner level 3 to 6, and 82.8% of patients with Tegner level 7 to 10. Age <25 years (odds ratio [OR], 7.4; P < .001) and higher Tegner levels (OR, 4.2; P < .001) were predictive of failing nonoperative treatment in multivariate analysis. Patients in the failed nonoperative group had longer time from diagnosis to surgery than the direct reconstruction group (6.2 vs 2.2 months; P < .001), and more frequently had new meniscal injuries (17.4% vs 3.1%; P < .001) at surgery.

Nonoperative treatment of ACL injuries failed in 60% of patients and was highly correlated with age and activity level. In patients aged 25 years or younger or participating in higher-impact sports, early ACL reconstruction should be considered to prevent longer delay between injury and surgery, as well as new meniscal injuries.

Arthroscopic anterior cruciate ligament (ACL) reconstruction (ACLR) with a bone–patellar tendon–bone graft (BTB) is a reliable surgical option for the control of anterior knee laxity after ACL injury. The addition of a lateral extra-articular tenodesis (LET) may improve control of rotation knee laxity and improve short-term graft survival in high-risk patients.

The aims of this study were to compare long-term patient-reported outcomes, graft survival, and risk of osteoarthritis between ACLR with and without LET.

Randomized controlled trial; Level of evidence, 2.

This study included 121 consecutive knees (120 patients) presenting to a single center with an ACL rupture between 1998 and 1999. In total, 61 knees were randomized to an isolated BTB ACLR, and 60 knees were randomized to a BTB ACLR with an extra-articular lateral tenodesis with gracilis tendon (modified Lemaire).

Eighty knees in 79 patients (66%) were available for follow-up at a postoperative mean of 19.4 years (range, 19-20.2). Of those patients, 43 had a clinical examination and completed patient-reported outcome questionnaires, and the other 37 patients were evaluated through the questionnaires alone. Standard radiographs were available for 45 patients and laximetry (TELOS) for 42 patients. Mean subjective International Knee Documentation Committee score at last follow-up was 81.8, and no differences were noted between the BTB and BTB-LET groups (P = .7). Two-thirds of patients were still participating in pivoting sports. A total of 17 knees (21%) experienced a graft failure, 5 of which (6%) underwent revision ACLR. There was no significant difference in graft failure risk between the BTB group (29%) and the BTB-LET group (13%; P = .1). Lateral tibiofemoral osteoarthritis was significantly more frequent in the BTB-LET group (59%) as compared with the BTB group (22%; P = .02). Lateral compartment osteoarthritis was correlated with partial lateral meniscectomy.

There were no significant differences in long-term patient-reported outcomes after ACLR with or without an LET. LET may increase the risk of lateral compartment osteoarthritis at long-term follow-up. There was a trend toward decreased graft failure risk with the addition of LET but this study was underpowered to assess this outcome.

The incidence of meniscocapsular junction tears of the medial meniscus posterior horn, known as ramp lesions, is reported to be 9.3% to 23.9%. However, these lesions are not consistently diagnosed with routine arthroscopic exploration and magnetic resonance imaging (MRI).

To determine risk factors associated with ramp lesions in anterior cruciate ligament–injured knees.

Cross-sectional study; Level of evidence, 3.

A total of 275 patients undergoing anterior cruciate ligament reconstruction between June 2011 and March 2019 were included in this study. Exclusion criteria were revisions, fracture histories, and multiple-ligament injuries other than medial collateral ligament injury. Patients were divided into 2 groups, those with and without ramp lesions according to arthroscopic diagnosis. Binary logistic regression was used to analyze risk factors: age, sex, body mass index, time from injury to surgery (<3 or ≥3 months), mechanism of injury (contact/noncontact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial/meniscal slope, and mechanical axis angle. Receiver operating characteristic curves and area under the curve were evaluated. A prediction model was developed by multivariable regression with generalized estimating equations.

Overall, 95 patients (34.5%) were confirmed as having a ramp lesion. The sensitivity of MRI for ramp lesions was 85.3%, and specificity was 78.3%. Significant risk factors for ramp lesion were as follows: posterior medial tibial plateau bone contusion on MRI (odds ratio [OR], 4.201; 95% CI, 2.081-8.482; P < .001), ≥3 months from injury (OR, 4.818; 95% CI, 2.158-10.757; P < .001), varus knee >3° (OR, 2.339; 95% CI, 1.048-5.217; P = .038), steeper medial tibial slope (OR, 1.289; 95% CI, 1.002-1.66; P = .049) and meniscal slope (OR, 1.464; 95% CI, 1.137-1.884; P = .003), and gradual lateral tibial slope (OR, 0.775; 95% CI, 0.657-0.914; P = .002). The area under the curve for the prediction model developed by logistic regression was 0.779 (sensitivity, 75.8%; specificity, 71.7%; P < .001) for ramp lesions.

Care should be taken with patients who have significant risk factors for ramp lesions, including bone contusion at the posterior medial tibial plateau, chronic injury, steeper medial tibial and meniscal slope, gradual lateral tibial slope, and varus knee >3°.

For many athletes, a tear of the anterior cruciate ligament (ACL) represents a significant injury that requires a prolonged period away from the sport with substantial rehabilitation.

There will be no difference in return to play (RTP) and career length after hamstring tendon (HT) ACL reconstruction in a group of Canadian Football League professional players as compared with what has been already been reported in the literature among professional football players.

Case-control study; Level of evidence, 3.

Data on athletes who sustained an ACL injury were collected by team physicians and head athletic trainers from 2002 to 2017 from 2 Canadian Football League teams. Patient details included age at the time of injury, initial injury date, position, practice versus game injury, and primary versus rerupture with injury-specific data, such as affected limb, concomitant injuries, graft choice, and procedure performed. RTP rates and career length data were collected through publically available internet sources. Comparisons between the non-RTP and RTP groups were made with independent-sample t tests. Binomial logistic regression was performed to determine variables (ie, games preinjury, graft type, meniscal injury, collateral ligament injury) that contributed to players not being able to RTP.

A total of 44 ACL reconstructions were performed over the study period (HT, n = 32 [72.7%]; bone–patellar tendon–bone [BPTB], n = 8 [18.2%]; allograft, n = 4 [9.1%]). Overall, 69.8% (n = 30) were able to RTP in at least 1 game, while 30.2% (n = 13) did not return. Mean time to return was 316.1 days (range, 220-427 days), or 10.4 months. For those players who did RTP, mean career length after ACL reconstruction was 2.8 seasons, or 34.4 games. The majority (56.8%) of injuries occurred early in the season. Breakdown by graft type demonstrated RTP rates among HT, BPTB, and allograft of 64.5% (n = 20), 87.5% (n = 7), and 75% (n = 3), respectively. Career length among HT, BPTB, and allograft was 2.9, 2.4, and 3 seasons. Logistic regression analysis found only concomitant medial collateral ligament (MCL) injuries to be a negative predictor for RTP. Meniscal injuries were associated with a decreased RTP rate and career length, but this was not statistically significant.

The RTP rates after ACL reconstruction in this study are similar to those reported in National Football League players. A concomitant injury to the MCL injury was a negative predictor of RTP. Meniscal injuries demonstrated a trend for decreased RTP rate and career length, but this was not a significant predictor. A large portion of injuries occur early in the season, and further study should be done to examine potential preventative strategies to reduce ACL injuries.

Patients often have quadriceps or hamstring weakness after anterior cruciate ligament reconstruction (ACLR), despite postoperative physical therapy regimens; however, little evidence exists connecting nerve blocks and ACLR outcomes.

To compare muscle strength at return to play in patients who received a nerve block with ACLR and determine whether a specific block type affected subjective knee function.

Cohort study; Level of evidence, 3.

Patients were recruited 5 to 7 months after primary, isolated ACLR and completed bilateral isokinetic strength tests of the knee extensor/flexor groups as a single-session return-to-sport test. Subjective outcomes were assessed with the International Knee Documentation Committee (IKDC) score. Strength was expressed as torque normalized to mass (N·m/kg) and limb symmetry index as involved/uninvolved torque. Chart review was used to determine the type of nerve block and graft used. Nerve block types were classified as knee extensor motor (femoral nerve), knee flexor motor (sciatic nerve), or isolated sensory (adductor canal block/saphenous nerve). A 1-way analysis of covariance controlling for graft type was used.

A total of 169 patients were included. Graft type distribution consisted of 102 (60.4%) ipsilateral bone–patellar tendon–bone (BTB) and 67 (39.6%) ipsilateral hamstring tendon. Nerve block type distribution consisted of 38 (22.5%) femoral, 25 (14.8%) saphenous, 45 (26.6%) femoral and sciatic, and 61 (36.1%) saphenous and sciatic. No significant difference was found in knee extensor strength (P = .113) or symmetry (P = .860) between patients with knee extensor motor blocks (1.57 ± 0.45 N·m/kg; 70.1% ± 15.3%) and those without (1.47 ± 0.47 N·m/kg; 69.6% ± 18.8%). A significant difference was found between patients with knee flexor motor blocks (0.83 ± 0.26 N·m/kg) and those without (0.92 ± 0.27 N·m/kg) for normalized knee flexor strength (P = .21) but not knee flexor symmetry (P = .592). Controlling for graft type, there were no differences in subjective knee function (IKDC score) between all nerve block groups (P = .57).

Our data showed that use of a sciatic nerve block with ACLR in patients with hamstring and BTB grafts influences persistent knee flexor strength deficits at time of return to sports. Although the cause of postoperative muscular weakness is multifactorial, this study adds to the growing body of evidence suggesting that perioperative nerve blocks affect muscle strength and functional rehabilitation after ACLR.

The aging process is accompanied by several conditions that could affect the outcome of meniscal allograft transplantation (MAT). These conditions have made it difficult for clinicians to determine the effect of chronologic age on survivorship after MAT.

Advanced age does not have an adverse effect on survivorship of MAT when controlling for age-related factors, such as cartilage status and time from previous meniscectomy.

Cohort study; Level of evidence, 3.

The records of 264 consecutive patients who underwent primary medial or lateral MAT were reviewed. To check whether there was a difference in MAT survivorship according to age, a cutoff value was calculated from a time-dependent receiver operating characteristic curve. Survival rates, as well as clinical improvement as determined using the Lysholm score, were compared between groups divided by the cutoff value. Patients were matched for cartilage status and elapsed time from previous meniscectomy. Differences in survivorship and clinical outcomes were assessed between the matched groups.

A time-dependent receiver operating characteristic curve showed that the difference in MAT survivorship was maximized with a cutoff age of 43 years. Kaplan-Meier analysis showed a significant difference in MAT survivorship between the older and younger groups (log-rank test, P = .01). However, after matching for cartilage status and time from previous meniscectomy, which left 56 patients per group, there was no significant difference in MAT survivorship (log-rank test, P = .10) between the groups. Regarding clinical outcomes, the mean Lysholm scores were not significantly different between the older and younger groups (P = .19, before matching; P = .39, after matching).

MAT survivorship was more affected by age-related prognostic factors, such as cartilage status and time from previous meniscectomy, than age itself. Clinical outcomes did not show differences according to age, either.

While the medial meniscal posterior horn (MMPH) is reported to bear a considerable portion of overall load on the knee joint, including compressive and shear forces, no study has yet investigated the relationship between the MMPH and posterior tibial slope (PTS), which is a geometric factor associated with the shear force component in the presence of a compressive load in the knee joint.

The purpose was to investigate the relationship between the PTS and MMPH tears in patients without ligamentous injury. It was hypothesized that the PTS is greater in patients with MMPH tears as compared with those without.

Cohort study; Level of evidence, 3.

From March 2015 to December 2018, 159 patients with isolated MMPH tears and 60 patients without any pathologic findings on magnetic resonance imaging (control group) were included in this study. The PTS in the affected and contralateral knees was compared between the groups, which were statistically matched according to baseline characteristics (ie, age, sex, body mass index, radiographic osteoarthritis grade according to the Kellgren-Lawrence scale, and hip-knee-ankle angle) via the inverse probability of treatment weighting method. Furthermore, the MMPH tear group was subdivided according to meniscal tear patterns; these subgroups were then compared with the control group.

The mean PTS was significantly greater in the MMPH tear group than in the control group (affected knee: MMPH tear group, 7.0°± 3.4° [mean ± SD]; control group, 5.2°± 2.1°, P < .001; contralateral knee: MMPH tear group, 6.7°± 3.3°; control group, 4.7°± 2.2°, P < .001). The mean PTS in each subgroup also tended to be greater than that in the control group. In the receiver operating characteristic curve analysis, the cutoff point of the PTS discriminating between the MMPH tear and control groups was 6.6° for the affected knee (sensitivity, 55.3%; specificity, 75.0%) and 5.5° for the contralateral knee (sensitivity, 61.0%; specificity, 76.7%).

An increased PTS is strongly associated with an increased incidence of MMPH tears and less affected by the meniscal tear patterns.

Patellofemoral joint (PFJ) osteoarthritis may occur after anterior cruciate ligament reconstruction (ACLR). The mechanisms underpinning the development of PFJ osteoarthritis are not known but may relate to altered PFJ loading. Few studies have assessed PFJ loads during high-impact tasks, such as running, beyond the acute rehabilitation phase (ie, >12 months) after ACLR.

The purpose was to compare between-limb joint angles, joint moments, and PFJ contact force during running in individuals at 12 to 24 months after unilateral ACLR. We hypothesized that peak knee flexion angle, knee extension moment, and PFJ contact force during stance would be lower in the ACLR limb compared with the uninjured limb.

Controlled laboratory study.

A total of 55 participants (mean ± SD age, 28 ± 7 years), 12 to 24 months after ACLR, ran at a self-selected speed (2.9 ± 0.3 m/s). Measured kinematics and ground-reaction forces were input into musculoskeletal models to calculate joint moments and muscle forces. These values were subsequently input into a PFJ model to calculate contact force peak and impulse. Outcome measures were compared between the ACLR and uninjured limbs.

In the ACLR limb, compared with the uninjured limb, the PFJ contact force displayed a lower peak (ACLR, 6.1 ± 1.3 body weight [BW]; uninjured, 6.7 ± 1.4 BW; P < .001) and impulse (ACLR, 0.72 ± 0.17 BW*seconds [BWs]; uninjured, 0.81 ± 0.17 BWs; P < .001). At the time of the peak PFJ contact force, the knee extension moment was lower in the ACLR limb (ACLR, 14.0 ± 2.4 %BW*height [%BW*HT]; uninjured, 15.5 ± 2.5 %BW*HT; P < .001). The opposite was true for the ankle plantarflexion moment (ACLR, 12.1 ± 2.6 %BW*HT; uninjured, 11.5 ± 2.7 %BW*HT; P = .019) and the hip extension moment (ACLR, 2.3 ± 2.5 %BW*HT; uninjured, 1.6 ± 2.3 %BW*HT; P = .013). The foot-ground center of pressure was located more anteriorly with respect to the ankle joint center (ACLR, 5.8 ± 0.9 %height [%HT]; uninjured, 5.4 ± 1.0 %HT; P = .001). No differences were found for the sagittal plane hip, knee, and ankle angles.

The ACLR limb experienced lower peak PFJ loads during running, explained by a small anterior shift in the foot-ground center of pressure during stance that offloaded the torque demand away from the ACLR knee.

Lower net PFJ loading during running in the ACLR limb more than 12 months after ACLR suggests that underloading might play a role in the onset of PFJ osteoarthritis after ACLR.

Early weightbearing protocols after Achilles tendon repair promote mobilization, yet little is known about their effect on tendon lengthening.

To evaluate tendon lengthening after Achilles tendon repair with accelerated rehabilitation.

Randomized controlled trial; Level of evidence, 1.

Patients undergoing primary repair for acute Achilles tendon ruptures consented to have tantalum beads placed within the tendon. Patients were randomized into either a traditional (weightbearing at 6 weeks) or accelerated (graduated weightbearing at 2 weeks) rehabilitation group. The primary outcome of the study was postoperative tendon elongation as measured by radiostereometric beads. Secondary outcomes included Achilles Tendon Total Rupture Score (ATRS) and Patient-Reported Outcomes Measurement Information System Pain Interference Short Form (PROMIS PI-SF) score.

All 18 patients included in the final analysis were found to have significant tendon lengthening after surgery, with a mean lengthening of 15.9 mm. No significant differences were found in overall lengthening between the traditional and accelerated rehabilitation groups (15.3 ± 4.5 vs 16.4 ± 4.7 mm, respectively; P = .33) at final follow-up. The repair site in each group was found to lengthen more than the intratendinous site (traditional group, 13.2 vs 2.1 mm; accelerated group, 16.8 vs −0.4 mm); however, no difference in lengthening was seen between groups (P = .82 and P = .31, respectively). The greatest amount of lengthening occurred between 2 and 6 weeks, and the least amount of lengthening occurred between 6 and 12 weeks, with no difference between the traditional and accelerated groups at these time points (P = .84 and P = .38, respectively). No differences were noted in ankle range of motion (dorsiflexion, P = .16; plantarflexion, P = .08) or outcome scores (ATRS, P = .56; PROMIS PI-SF, P = .54).

This study’s findings demonstrate that all patients undergoing operative repair of Achilles tendon ruptures had lengthening after surgery. No difference was found in tendon lengthening (repair site or intratendinous) at any time point between patients undergoing traditional versus accelerated rehabilitation postoperatively. The greatest amount of lengthening was found to occur between 2 and 6 weeks postoperatively, and tendon lengthening decreased significantly after 6 weeks.

NCT04050748 (ClinicalTrials.gov identifier).

Platelet-rich plasma (PRP) is widely used in sports medicine. However, neither preparation nor parameters for clinical application, such as concentration, timing, and number of applications, are standardized, making research and clinical utilization challenging.

To investigate the effect of varying doses of PRP powder in terms of different concentrations, timing, and number of applications on human chondrocytes in a reproducible cell culture model.

Controlled laboratory study.

A standardized lyophilized platelet growth factor preparation (PRP powder) was used to stimulate human chondrocytes. Chondrocytes were cultivated for 2 weeks with different stimulation frequencies (2×, 3×, 6×) and different concentrations of PRP powders (0.5%, 1%, 5%). Cell proliferation and metabolic cell activity were analyzed on days 7 and 14. Phenotypic changes were visualized through live-dead staining. Chondrogenic differentiation was quantified with enzyme-linked immunosorbent assay to assess the synthesis of procollagen types 1 and 2. Furthermore, sulfated proteoglycans and glycosaminoglycans were analyzed.

Human chondrocytes exhibited a significant dose- and time-dependent increase after 14 days in cell number (1% and 5% PRP powder vs unstimulated control: 7.95- and 15.45-fold increase, respectively; 2× vs 6× stimulation with 5% PRP powder: 4.00-fold increase) and metabolic cell activity (1% and 5% PRP powder vs unstimulated control: 3.27-fold and 3.58-fold change, respectively). Furthermore, cells revealed a significant increase in the amount of bone-specific procollagen type 1 (14 days, 1.94-fold) and sulfated glycosaminoglycans (14 days, 2.69-fold); however, no significant change was observed in the amount of cartilage-specific collagen type 2.

We showed that chondrocytes exhibit a significant dose- and time-dependent increase in cell number and metabolic cell activity. The standardized use of growth factor concentrates in cell culture models can contribute to clinical knowledge in terms of dosage and timing of PRP applications.

Problems with PRP, such as the absence of standardization, lack of consistency among studies, and unknown dosage, could be solved by using characterized PRP powder made by pooling and lyophilizing multiple platelet concentrates. The innovative PRP powder generates new possibilities for PRP research, as well as for the treatment of patients.

Articular cartilage has a zonal architecture and biphasic mechanical properties. The recapitulation of surface lubrication properties with high compressibility of the deeper layers of articular cartilage during regeneration is essential in achieving long-term cartilage integrity. Current clinical approaches for cartilage repair, especially with the use of mesenchymal stem cells (MSCs), have yet to restore the hierarchically organized architecture of articular cartilage.

MSCs predifferentiated on surfaces with specific nanotopographic patterns can provide phenotypically stable and defined chondrogenic cells and, when delivered as a bilayered stratified construct at the cartilage defect site, will facilitate the formation of functionally superior cartilage tissue in vivo.

Controlled laboratory study.

MSCs were subjected to chondrogenic differentiation on specific nanopatterned surfaces. The phenotype of the differentiated cells was assessed by the expression of cartilage markers. The ability of the 2-dimensional nanopattern-generated chondrogenic cells to retain their phenotypic characteristics after removal from the patterned surface was tested by subjecting the enzymatically harvested cells to 3-dimensional fibrin hydrogel culture. The in vivo efficacy in cartilage repair was demonstrated in an osteochondral rabbit defect model. Repair by bilayered construct with specific nanopattern predifferentiated cells was compared with implantation with cell-free fibrin hydrogel, undifferentiated MSCs, and mixed-phenotype nanopattern predifferentiated MSCs. Cartilage repair was evaluated at 12 weeks after implantation.

Three weeks of predifferentiation on 2-dimensional nanotopographic patterns was able to generate phenotypically stable chondrogenic cells. Implantation of nanopatterned differentiated MSCs as stratified bilayered hydrogel constructs improved the repair quality of cartilage defects, as indicated by histological scoring, mechanical properties, and polarized microscopy analysis.

Our results indicate that with an appropriate period of differentiation, 2-dimensional nanotopographic patterns can be employed to generate phenotypically stable chondrogenic cells, which, when implanted as stratified bilayered hydrogel constructs, were able to form functionally superior cartilage tissue.

Our approach provides a relatively straightforward method of obtaining large quantities of zone-specific chondrocytes from MSCs to engineer a stratified cartilage construct that could recapitulate the zonal architecture of hyaline cartilage, and it represents a significant improvement in current MSC-based cartilage regeneration.

The acetabular labrum is critical to maintenance of hip stability and has been found to play a key role in preservation of the hip fluid seal. For irreparable labral damage, arthroscopic labral reconstruction is an evolving technique that has been shown to decrease hip pain and restore function.

To provide a comprehensive review of current literature for arthroscopic hip labral reconstruction, with a focus on determining if outcomes differ between autograft or allograft tissue.

Systematic review and meta-analysis.

PubMed and Scopus online databases were searched with the key terms “hip,”“labrum,”“reconstruction,” and “graft” in varying combinations. Procedures performed, complications, failures, and functional outcome measures were included in this analysis. The inverse variance method was used to calculate pooled estimates and 95% CIs.

Eight studies with 537 hips were included. Mean age was 37.4 years (95% CI, 34.5-40.4 years), and mean follow-up time was 29 months (95% CI, 26-33 months). Survivorship after autograft reconstruction ranged from 75.7% to 100%, as compared with 86.3% to 90.0% in the allograft cohort. In the autograft cohort, failures included 0% to 13.2% conversion to total hip arthroplasty and 0% to 11.0% revision hip arthroscopy. Failures in the allograft cohort included 0% to 12.9% total hip arthroplasty conversion, 0% to 10.0% revision arthroscopy, and 0% to 0.8% open revision surgery. Based on 6 studies, the modified Harris Hip Score improved by a mean 29.0 points after labral reconstruction (P < .0001).

Arthroscopic hip labral reconstruction results in clinically significant improvements in patient-reported outcomes. Our analysis indicates that there are no significant differences in outcomes based on graft type alone. A number of factors may determine graft choice, including patient preference, surgeon experience, operative time, morbidity, and cost. Proper patient selection based on age and severity of degenerative joint disease will also optimize outcomes after labral reconstruction.

Many surgical options for treating patellofemoral (PF) cartilage lesions are available but with limited evidence comparing their results.

To determine and compare outcomes of PF cartilage restoration techniques.

Systematic review and meta-analysis.

PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines were followed by utilizing the PubMed, EMBASE, and Cochrane Library databases. Inclusion criteria were clinical studies in the English language, patient-reported outcomes after PF cartilage restoration surgery, and >12 months’ follow-up. Quality assessment was performed with the Coleman Methodology Score. Techniques were grouped as osteochondral allograft transplantation (OCA), osteochondral autograft transfer (OAT), chondrocyte cell–based therapy, bone marrow–based therapy, and scaffolds.

A total of 59 articles were included. The mean Coleman Methodology Score was 71.8. There were 1937 lesions (1077 patellar, 390 trochlear, and 172 bipolar; 298 unspecified). The frequency of the procedures was as follows, in descending order: chondrocyte cell–based therapy (65.7%), bone marrow–based therapy (17.2%), OAT (8%), OCA (6.6%), and scaffolds (2.2%). When compared with the overall pooled lesion size (3.9 cm²; 95% CI, 3.5-4.3 cm²), scaffold (2.2 cm²; 95% CI, 1.8-2.5 cm²) and OAT (1.5 cm²; 95% CI, 1.1-1.9 cm²) lesions were smaller (P < .001), while chondrocyte cell–based therapy lesions were larger (4.7 cm²; 95% CI, 4.1-5.3 cm²; P = .039). Overall, the instability pool was 11.9%, and the anatomic risk factors pool was 32.1%. Statistically significant improvement was observed on at least 1 patient-reported outcome in chondrocyte cell–based therapy (83%), OAT (78%), OCA (71%), bone marrow–based therapy (64%), and scaffolds (50%). There were no significant differences between any group and the overall pooled change in International Knee Documentation Committee score (30.2; 95% CI, 27.4-32.9) and Lysholm score (25.2; 95% CI, 16.9-33.5). There were no significant differences between any group and the overall pooled rate in minor complication rate (7.6%; 95% CI, 4.7%-11.9%) and major complication rate (8.3%; 95% CI, 5.7%-12.0%); however, OCA had a significantly greater failure rate (22.7%; 95% CI, 14.6%-33.4%) as compared with the overall rate (6.8%; 95% CI, 4.7%-9.5%).

PF cartilage restoration leads to improved clinical outcomes, with low rates of minor and major complications. There was no difference among techniques; however, failures were higher with OCA.

The effectiveness of blood flow restriction training (BFRT) as compared with other forms of training, such as resistance training, has been evaluated in the literature in clinical and nonclinical populations. However, the safety of this intervention has been summarized only in healthy populations and not in clinical populations with musculoskeletal disorders.

To evaluate the safety and adverse events associated with BFRT in patients with musculoskeletal disorders.

Systematic review.

A literature search was conducted with 3 online databases (MEDLINE, CINAHL, and Embase). Eligibility criteria for selecting studies were as follows: (1) BFRT was used as a clinical intervention, (2) study participants had a disorder of the musculoskeletal system, (3) authors addressed adverse events, (4) studies were published in English, and (5) the intervention was performed with human participants.

Nineteen studies met eligibility criteria, with a pooled sample size of 322. Diagnoses included various knee-related disorders, inclusion body myositis, polymyositis or dermatomyositis, thoracic outlet syndrome, Achilles tendon rupture, and bony fractures. Nine studies reported no adverse events, while 3 reported rare adverse events, including an upper extremity deep vein thrombosis and rhabdomyolysis. Three case studies reported common adverse events, including acute muscle pain and acute muscle fatigue. In the randomized controlled trials, individuals exposed to BFRT were not more likely to have an adverse event than individuals exposed to exercise alone. Of the 19 studies, the adverse events were as follows: overall, 14 of 322; rare overall, 3 of 322; rare BFRT, 3 of 168; rare control, 0 of 154; any adverse BFRT, 10 of 168; any adverse control, 4 of 154. A majority of studies were excluded because they did not address safety.

BFRT appears to be a safe strengthening approach for knee-related musculoskeletal disorders, but further research is needed to make definitive conclusions and to evaluate the safety in other musculoskeletal conditions. Improved definitions of adverse events related to BFRT are needed to include clear criteria for differentiating among common, uncommon, and rare adverse events. Finally, further research is needed to effectively screen who might be at risk for rare adverse events.