The American Journal of Sports Medicine

The knee’s inflammatory response to ligamentous, meniscal, and cartilage injuries is complex and incompletely understood, particularly in the setting of concomitant injuries. Recent research has highlighted the potential utility of synovial fluid biomarker analysis in identifying factors involved in the progression of posttraumatic osteoarthritis.

To investigate if unique patterns of knee injury are associated with distinct synovial fluid biomarker profiles at the time of surgical intervention.

Cross-sectional study; Level of evidence, 3.

Patients undergoing arthroscopic knee surgery were prospectively enrolled and asked to complete the Lysholm Knee Scoring Scale and visual analog scale for pain preoperatively. Synovial fluid was aspirated from the operative knee before surgical incision, and the concentrations of 10 biomarkers of interest were quantified. Patients with intraoperative evidence of articular cartilage, meniscal, and/or anterior cruciate ligament (ACL) injury were identified and included for subsequent analysis. Biomarker concentrations were log-normalized and standardized. Principal component analysis (PCA) was performed using biomarker variables to reduce dimensionality and extract key patterns. Multivariable linear regression for each retained principal component (PC) was performed with the predictors of age, sex, body mass index, symptom duration, ACL injury, meniscal injury, and Outerbridge grade. A separate regression analysis was performed to assess relationships between PCs and patient-reported outcomes controlling for the same variables.

A total of 387 patients were included in the analysis, of whom 176 (45.5%) had ACL rupture, 327 (84.5%) had meniscal injury, and 225 (58.1%) had cartilage injury. PCA yielded 3 PCs (PC1, PC2, and PC3) that explained 66.9% of variance in biomarker data. PC1 was found with significant loadings of VEGF, IL-6, MMP-3, MIP-1β, and MCP-1; PC2 with TIMP-1 and TIMP-2; and PC3 with RANTES, bFGF, and IL-1RA. Multivariable linear regression found ACL injury (P = .014; β = .164) and meniscal injury (P = .029; β = .118) to be positively associated with PC1, Outerbridge grade to be negatively associated with PC2 (P = .041; β = –.132), and ACL injury to be positively associated with PC3 (P = .035; β = .141). PC1 was associated with a worse preoperative Lysholm score (P = .001; β = –.199).

Cartilage lesions exhibited a synovial fluid inflammatory profile distinct from ACL and meniscal injury at the time of knee arthroscopy. While ACL and meniscal injuries displayed a pro-inflammatory phenotype, more severe cartilage lesions were associated with a reduced presence of anti-inflammatory markers. The pro-inflammatory phenotype also independently correlated with worse baseline knee function. These findings contribute to the understanding of the pathophysiology of ligamentous, meniscal, and cartilage injuries and may aid in the identification of pathology-specific treatments to help alter the natural history of disease.

Anterior cruciate ligament (ACL) injuries and reconstruction are associated with alterations in chondral homeostasis and posttraumatic osteoarthritis. Biomarkers of chondral metabolism may have a role in quantitatively evaluating this phenomenon.

To describe changes in 3 systemic biomarkers of chondral metabolism and extracellular matrix remodeling during the first year after ACL reconstruction and to identify factors associated with biomarker concentrations at the baseline and 12-month postoperative timepoints.

Controlled laboratory study.

From a longitudinal study, urine and serum samples were taken immediately before primary ACL reconstruction and at 6 and 12 months postoperatively. A total of 666 patients provided samples (mean ± SD age, 24.9 ± 7.2 years; 60.5% male). Immunoassays were used to measure concentrations of urinary C-terminal cross-linked telopeptide of type 2 collagen (CTX-II), a marker of type 2 collagen degradation; serum N-propeptide of collagen IIA (PIIANP), a marker of type 2 collagen synthesis; and serum matrix metalloproteinase 3 (MMP-3), a mediator of extracellular matrix remodeling. Linear mixed modeling and linear regression were used for data analysis.

Urinary CTX-II concentrations decreased by 25% (95% CI, 19%-31%) from baseline to 6 months and by 37% (95% CI, 22%-42%) from baseline to 12 months, respectively (P < .001). Serum PIIANP increased by 40% (95% CI, 34%-47%) from baseline to 6 months (P < .001) with no significant change between 6 and 12 months. Serum MMP-3 increased by 35% (95% CI, 29%-42%) and 44% (95% CI, 37%-52%) from baseline to 6 months and from baseline to 12 months respectively (P < .001). At the baseline timepoint, age, body mass index (BMI), sex, and time from injury to surgery were factors associated with biomarker concentrations. At the 12-month timepoint, age, sex, BMI, and time from injury to surgery were associated with biomarker concentrations.

Decreasing urinary CTX-II concentrations coupled with increasing serum PIIANP concentrations may suggest a reparative chondral response within the first 12 months after ACL reconstruction. Increasing serum MMP-3 concentrations suggested persistent and progressive extracellular matrix remodeling during this same period. Predominantly nonmodifiable demographic factors were associated with baseline and 12-month concentrations of the 3 biomarkers.

Biomarkers of chondral metabolism may have future prognostic or decision-making roles in the management of patients with ACL injury. This could include predicting posttraumatic arthritis.

Changes in systemic biomarkers of chondral metabolism have been identified after anterior cruciate ligament (ACL) reconstruction. Patients with extremely high biomarker concentrations (outlier patients) are often observed and may represent a group at high risk for posttraumatic arthritis. It is unclear if outlier status changes over time, and if it can be explained by patient, injury, and surgical factors.

To evaluate outlier status changes over time for 3 biomarkers of chondral metabolism after ACL injury and reconstruction and describe factors associated with outlier status.

Cohort study; Level of evidence, 2.

Patients from a prospective longitudinal study were included. Urine and serum samples were taken immediately before primary ACL reconstruction and at 6 and 12 months postoperatively. A total of 666 patients provided samples (mean age, 24.9 years; 60.5% male). Concentrations of urinary C-terminal cross-linked telopeptide of type 2 collagen (u-CTX-II), serum N-propeptide of collagen 2A (s-PIIANP), and serum matrix metalloproteinase 3 (s-MMP-3) were measured using immunoassays. Outlier status was defined as values above quartile 3 plus 1.5 times the interquartile range for each biomarker. Multivariable logistic regression models were developed with biomarker outlier status as the dependent variable and patient, injury, and surgical factors as explanatory variables.

At the baseline time point, the proportion of outliers was 9.29% for u-CTX-II, 1.97% for s-PIIANP, and 12.42% for s-MMP-3. Outlier patients at baseline were commonly also outliers at one or both of the future time points in terms of u-CTX-II (88.3%) and s-MMP-3 (82.93%). In contrast, for s-PIIANP outlier patients at baseline, only 15.38% were outliers at a future time point. It was uncommon for nonoutlier patients at baseline to become an outlier at either of the future time points (u-CTX-II: 6.83%; s-PIIANP: 2.32%; s-MMP-3: 2.08%). Patient and surgical factors had poor ability to discriminate between outlier and nonoutlier patients for s-PIIANP (Tjur R² = 0.056) and s-MMP-3 (Tjur R² = 0.013). However, for u-CTX-II (Tjur R² = 0.598), younger age, shorter time from injury to surgery, lower body mass index, and male sex were independently associated with outlier u-CTX-II concentrations at baseline.

Outlier patients were observed when measuring all 3 systemic biomarkers of chondral metabolism after ACL reconstruction. For s-PIIANP and sMMP-3, outlier status was poorly explained by patient or surgical factors, but for u-CTX-II, outlier status could, in part, be explained by patient and surgical factors. These results support longitudinal biomarker analyses, given that outlier status can change over time, and this may not be identified in cross-sectional study designs.

Approximately 55% of individuals return to previous sports levels after anterior cruciate ligament (ACL) reconstruction (ACLR), but the duration of their sporting life post-ACLR and how this differs from uninjured sports participants is unknown.

To trace the 25-year trajectory of sports participation in individuals who have undergone ACLR and compare sporting activity between graft types and between ACLR individuals and uninjured controls.

Cohort study; Level of evidence, 3.

A total of 62 individuals (44 males; mean age, 27 years) underwent ACLR (31 bone–patellar tendon–bone grafting, 31 semitendinosus/gracilis grafting). Sporting activity was assessed preinjury, at 6 and 25 years after surgery on a 6-point scale based on pivoting demands. A total of 30 uninjured individuals matched for age, sex, and sporting activity were assessed at equivalent time points. Pearson chi-square and Student t tests were used to compare outcomes between graft types and between ACLR individuals and controls.

In total, 50 (81%) individuals (35 males) with ACLR and 20 (67%) uninjured controls were followed up after 25 years. Overall, 88% of the ACLR group were active in sports, 22% in vigorous pivoting sports. Three ACLR individuals had total knee replacements, 9 ruptured their contralateral ACL, and 8 ruptured their graft. There was no significant difference between graft types in sports level played presurgery (P = .442), 6 years after surgery (P = .511), or 25 years after surgery (P = .100). At 25 years after surgery, ACLR individuals participated in sports at higher levels (P = .005) and over longer periods (P = .032) than controls.

Interestingly, after ACLR, patients were more engaged in sports than uninjured controls. Although the level of sports activity typically decreased over 25 years, findings highlight the potential for longevity in sports after an ACLR, irrespective of graft type.

Cyclops syndrome is a common yet poorly understood complication after anterior cruciate ligament (ACL) reconstruction (ACLR), resulting in loss of knee extension that sometimes requires revision surgery for debridement. Limited agreement in the literature exists on the risk profile of patients who develop cyclops syndrome.

The purpose was to define a risk profile indicating which individuals are predisposed to reoperation for cyclops syndrome after primary ACLR. It was hypothesized that high posterior tibial slope (PTS), narrow notch, large grafts, and higher grades of remnant preservation would be associated with reoperation for cyclops syndrome.

Case-control study; Level of evidence, 4.

Primary ACLRs performed by academic sports medicine surgeons at a single large integrated health care network between 2014 and 2021 were included. Variables including patient characteristics, knee hyperextension, instability grade, graft type and diameter, meniscal procedures, femoral notch width, ACL remnant preservation, graft/tissue impingement, tunnel position, and PTS were collected. Univariate analyses and multiple regression were performed to identify risk factors associated with reoperation for cyclops syndrome within 24 months after ACLR.

A total of 1163 consecutive primary ACLRs were included (mean age, 24.9 years). The overall rate of reoperation for cyclops syndrome was 5.5%. No statistically significant differences in rates of reoperation for cyclops syndrome were identified based on surgical timing, graft type, graft diameter, or meniscal repair. Additionally, ACL remnant grade, excessive graft anterior tissue coverage, and tibial tunnel position were not associated with the development of symptomatic cyclops syndrome. On univariate analyses, contralateral knee hyperextension (P = .04) and increased PTS >12° (P = .004) were found to be potential risk factors for cyclops syndrome. After controlling for PTS, narrow femoral notch, and femoral tunnel placement, stepwise subset multiple regression analysis (n = 351) identified knee hyperextension as an independent predictor of reoperation for cyclops syndrome (OR, 2.40; P = .049).

After controlling PTS, narrow femoral notch, and proximal femoral tunnel placement, contralateral knee hyperextension was found to be an independent predictor for reoperation for cyclops syndrome necessitating surgical debridement after primary ACLR. Surgical delay, graft type, graft diameter, meniscal repair, remnant preservation, or excessive anterior graft tissue were not found to be associated with reoperation for cyclops syndrome.

Posterior tibial slope (PTS) has been implicated in tunnel widening after anterior cruciate ligament reconstruction (ACLR), yet its precise effect remains unclear. Additionally, the influence of lateral extra-articular tenodesis (LET) and meniscus root injuries on tunnel widening has not been well established.

To evaluate the effect of medial and lateral PTS, LET, and meniscus root injuries on tibial and femoral tunnel widening after ACL reconstruction using a hamstring tendon graft.

Cohort study; Level of evidence, 3.

A total of 307 patients who underwent primary ACLR with a hamstring tendon graft were included. Tibial and femoral tunnel diameters were measured immediately postoperatively and at 2-year follow-up. PTS was assessed by long lateral radiographs. Univariate and multivariate regression models were used to identify predictors of tunnel widening.

At 2 years, the mean ± Standard Deviation (SD) tibial tunnel diameter increased from 9.46 ± 1.00 mm postoperatively to 11.35 ± 1.55 mm (P < .001), and the mean femoral tunnel diameter increased from 9.27 ± 0.83 mm to 11.52 ± 1.63 mm (P < .001). Univariate analysis demonstrated that steeper medial and lateral PTS were significantly associated with tibial (P < .0001) and femoral (P < .0001) tunnel widening. Meniscus root injuries (P = .0024) and higher body mass index (P = .0127) were also associated with increased tunnel widening. In multivariate regression, medial PTS (β = −0.321; P < .0001), lateral PTS (β = −0.137; P = .0356), LET (β = 0.2207; P = .0257), and meniscus root injuries (P = .0024) remained independent predictors of tunnel widening.

Steeper medial and lateral PTSs, the addition of LET, and the presence of meniscus root injuries are significant independent predictors of tibial and femoral tunnel widening after ACLR with a hamstring graft. These findings highlight key anatomic and surgical factors influencing postoperative tunnel remodeling and emphasize the importance of considering these variables in ACLR planning.

The femoral attachment of the anterolateral ligament (ALL) reported by anatomic studies is posterior and proximal to the lateral femoral epicondyle.

To assess the femoral positioning of the ALL graft while performing a percutaneous technique and evaluate the correlation between this positioning and the graft rupture rate, as well as clinical and functional outcomes.

Cohort study; Level of evidence, 3.

A total of 211 patients undergoing combined anterior cruciate ligament (ACL) and ALL reconstruction were included. Radiological measurements, Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, and graft failure rate were collected at 24 months after surgery.

The rate of anatomic positioning of ALL femoral anchors was 79.1% (n = 167). The mean proximal and posterior distances relative to the ALL anatomic femoral position were 1.4 ± 2.8 mm and 0.2 ± 0.2 mm, respectively. The rate of outliers, defined as >5 mm from the anatomic position, was 20.85% (n = 44). The mean KOOS and IKDC score were 84 ± 10.9 and 80.1 ± 11.3, respectively. No statistically significant difference in KOOS and IKDC score was observed between the group of patients with anatomic positioning and the group of outliers (P = .1). The rate of ACL rerupture for all patients was 3.79% (n = 8). Of these, 87.5% (n = 7) were outliers. The correlation between ALL femoral malpositioning and ACL rerupture was statistically significant (P < .00001).

Independent ALL reconstruction while performing a percutaneous technique enabled anatomic positioning of the ALL graft in 79% of cases. The femoral malpositioning was correlated with a higher ACL graft rerupture rate but not with a decrease in the functional outcomes.

Incidence rates of pediatric anterior cruciate ligament (ACL) injuries and ACL reconstruction (ACLR) are increasing. In adult patients with ACLR, limb-level loading profiles are less dynamic compared with uninjured controls (ie, lesser peaks and minimal offloading during midstance) early post-ACLR, and less dynamic profiles are associated with deleterious knee tissue changes. However, joint-level loading magnitudes during gait in the pediatric ACLR population are unknown.

The purpose of this study was to compare medial and lateral tibiofemoral joint contact force profiles between pediatric patients with ACLR and pediatric matched controls. It was hypothesized that pediatric patients with ACLR would demonstrate less dynamic medial and lateral joint contact force profiles compared with matched uninjured pediatric controls.

Cross-sectional study; Level of evidence, 2.

Pediatric patients 6 to 24 months post-ACLR (n = 25) and matched pediatric controls (n = 25; Tanner stage category, sex, Tegner activity score ±3) underwent a gait biomechanical assessment at a single time point, where ground-reaction forces and marker trajectories were collected. The concurrent optimization of muscle activation and kinematics algorithm was utilized to estimate medial and lateral compartment tibiofemoral joint contact forces in the ACLR limb and pediatric matched control limb. A functional linear model was utilized to determine differences in joint contact force profiles throughout stance phase (0%-100%).

Pediatric patients with ACLR demonstrated a high occurrence of concomitant injuries (80% meniscal pathology; 13% chondral injuries) and walked with greater medial tibiofemoral joint contact forces in midstance (42%-63% of the stance phase; 339-N maximal difference) and greater lateral joint contact forces in the late stance compared with pediatric controls (69%-80%; 288 N).

Pediatric patients with ACLR may demonstrate a less dynamic tibiofemoral joint contact force loading profile in the medial compartment, as evidenced by greater loading during midstance, compared with matched pediatric controls.

Donor-recipient sex mismatch for tissue and organ transplantation has been shown to negatively affect outcomes.

To analyze the effect of sex mismatching on outcomes after meniscal allograft transplantation (MAT) and to determine if there is an association between the sex of the recipient and the sex of the donor and how this affects clinically significant outcome (CSO), reoperation, and failure rates after primary MAT.

Case series; Level of evidence, 4.

Between 2003 and 2022, patients who underwent MAT were prospectively followed, with the inclusion criteria of having undergone primary MAT and having a minimum of 2 years’ follow-up. Patient characteristics and clinical data, as well as donor age, donor sex, and graft expiration date, were collected. Reoperation and failure data were also collected, and patients were evaluated for achieving CSOs for the International Knee Documentation Committee (IKDC) score. A reoperation was any surgical intervention involving the transplanted allograft, including second-look arthroscopic surgery in the setting of recurrent symptoms or functional deficits, meniscectomy, and meniscal repair. Failure was defined as revision MAT and unicompartmental or total knee arthroplasty. Survivorship was assessed with a Kaplan-Meier curve. Log-rank testing evaluated survivorship between groups.

A total of 245 patients met the inclusion criteria and were followed for a mean of 8.4 ± 4.2 years (range, 2.0-19.1 years). Isolated MAT was performed in 73 of 247 knees (30%). There was a significantly greater prevalence of female knees (89/129 [69%]) than male knees (10/118 [9%]) that received a graft from the opposite sex (P < .001). On average, graft recipients were younger in the mismatch group than in the nonmismatch group (25.4 ± 8.5 vs 28.6 ± 8.8 years, respectively; P = .004). No donor variables were predictive of achieving CSOs for the IKDC score at 5 years. No difference in rates of survivorship from reoperations or failure was observed.

Donor variables, including sex, age, and donor-recipient sex mismatch, did not negatively affect clinical outcomes. These findings suggest that sex matching is not necessary for graft selection, potentially increasing the availability of allografts and facilitating MAT in the setting of limited donor availability.

The identification of the medial patellofemoral ligament (MPFL) insertion site relies heavily on the use of radiographic landmarks such as the Schöttle point. However, little is known on how the variation in condylar alignment and beam directionality affects this perceived location.

To quantify changes in the perceived MPFL insertion site when posterior proximal or posterior distal condylar alignment is optimized and when fluoroscopic beam directionality alters.

Controlled laboratory study.

A total of 16 cadaveric knees were included. The femoral insertion of the MPFL was identified and fixed with a radiopaque metal marker after dissection. Fluoroscopic images in the medial-to-lateral (ML) direction were taken with the posterior proximal condyles aligned and then with the posterior distal condyles aligned. Beam directionality was flipped to the lateral-to-medial (LM) direction, and images with posterior proximal and posterior distal condylar alignment were taken. Images were then superimposed onto the reference image, with discrepancies between marker locations quantified in the x- and y-axis. The 2-tailed Student t test was performed on all obtained variations.

In the ML direction, proximal versus distal alignment resulted in a mean proximal displacement of 0.43 ± 1.86 mm (P = .37) and a mean posterior displacement of −0.11 ± 0.55 mm (P = .42). In the LM direction, proximal versus distal alignment resulted in a mean proximal displacement of 1.95 ± 2.37 mm (P = .005) and a mean anterior displacement of 0.22 ± 1.95 mm (P = .67). When comparing ML to LM beam directionality with optimized proximal condylar alignment, there was a mean distal displacement of −0.26 ± 1.73 mm (P = .56) and a mean anterior displacement of 2.22 ± 1.87 mm (P < .001). When comparing ML to LM beam directionality with optimized distal condylar alignment, there was a mean proximal displacement of 1.26 ± 2.53 mm (P = .07) and a mean anterior displacement of 2.55 ± 1.71 mm (P < .001).

Beam directionality and condylar alignment affected the perceived location of the MPFL insertion. However, shooting in the ML direction and aligning the posterior proximal femoral condyles resulted in the least amount of total variation. Future studies are needed to determine the amount of variation in perceived MPFL insertion sites that are clinically significant.

This information provides surgeons with the insight that beam directionality and condylar alignment significantly affect the perceived location of the MPFL insertion site and that surgeons can use fluoroscopic imaging in the ML direction with posterior proximal condylar alignment to minimize image variation.

High-level basketball athletes at the collegiate level and in the National Basketball Association (NBA) have a greater proportion of knee cartilage pathology than the nonathlete population. However, little is known as to whether identified pathology on knee magnetic resonance imaging (MRI) correlates with clinical symptoms or orthopaedic history in these players.

(1) To evaluate knee MRI scans in a cross-sectional population of NBA Draft Combine players to establish prevalence of knee pathology, including that of articular cartilage and meniscus in professional basketball players. (2) To identify independent variables including demographic characteristics, playing history, previous knee injury, and symptoms that correlate to these MRI findings.

Cross-sectional study; Level of evidence, 3.

Players from the NBA Draft Combine over a 2-year period voluntarily participated by undergoing bilateral knee MRI scanning and completing clinical questionnaires. MRI scans were independently and blindly evaluated by 2 radiologists for cartilage assessment (using modified Noyes score) and meniscal pathology. Associations between imaging findings and pain/function scores and orthopaedic history were evaluated.

A total of 43 players (80 knees) were included. Intraclass correlation coefficients were a mean of 0.827 for agreement and 0.831 for consistency for the modified Noyes score. Cartilage pathology was identified in 48.3% of knees, with the most common locations being the patella and trochlea. Previous knee surgery was associated with lateral tibial plateau chondral pathology (odds ratio [OR], 6.58; P = .04). Reduced function scores were predictive of cartilage pathology on the lateral femoral condyle (OR, 0.55; P = .03). Increased pain scores were associated with a nonzero modified Noyes score (OR, 6.11; P < .01).

The incidence of pathology identified on knee MRI scans in players at the NBA Draft Combine without clinical symptoms was high, in line with the hypothesis. Little correlation was found between the objective imaging findings and subjective pain, function, and orthopaedic injury history. Clinicians treating high-level athletes should focus on treating clinically significant findings and be cautious about treating pathology found on imaging that may not explain or correlate with symptoms. It remains critical to study the natural history of imaging findings in these athletes to better ascertain the ultimate effect of sport and physiologic load on disease progression.

Despite increases in gender, racial, and ethnic representation in medical school, orthopaedics continues to be recognized as one of the least diverse fields in medicine, as progress in achieving a more diverse orthopaedic community has not occurred nearly as rapidly.

To ascertain and discuss the current state of racial, ethnic, and gender demographic trends in orthopaedic surgery sports medicine fellowships from 2007 to 2024.

Descriptive epidemiology study.

Fellowship demographic data were collected through the Accreditation Council for Graduate Medical Education. Data include gender, race and ethnicity, and total number of orthopaedic sports medicine fellows. Percentage equivalents were calculated for each group from 2007 to 2024. A χ² test for trend was conducted to determine if there was a significant change in the percentages of each race, ethnicity, and gender during the study period. Results were considered statistically significant at P < .05. The 114 fellows (3.2%) who did not report gender and 468 fellows (16.8%) who reported other or unknown were excluded from their respective analyses.

From 2007 to 2024, White non-Hispanic males composed the majority of sports medicine fellowship positions. White non-Hispanic representation ranged from 74.9% to 88.2%, Asian from 6.6% to 16.3%, Hispanic from 0.0% to 8.4%, and Black non-Hispanic from 1.5% to 6.9%. There was a significant increase in the proportion of Hispanic orthopaedic sports medicine fellows (P = .001) but no other significant changes among the racial and ethnic makeup of fellows. There was a significant increase in the representation of female fellows (P = .041), with a range of 5.4% to 13.2%.

Our study reveals a significant increase in female and Hispanic representation among orthopaedic sports medicine fellows from 2007 to 2024, but no other racial or ethnic groups showed significant change. The disparities identified in our study suggest that systemic interventions throughout the orthopaedic education pipeline may be necessary to improve sports medicine fellowship diversity.

The timing for anterior cruciate ligament (ACL) reconstruction (ACLR) and strategies to enhance postoperative healing remain controversial, with little known regarding potential sex-specific differences. Perioperative adenosine, lidocaine, and Mg²⁺ (ALM) therapy has been shown to promote joint tissue healing in an experimental model of early ACLR; however, an early-late comparison of ALM’s effects on postoperative recovery remains to be investigated.

To examine the effect of delayed surgery in males and females, and the effect of ALM therapy to augment joint tissue healing.

Controlled laboratory study.

After noninvasive ACL rupture, adult male (n = 38) and female (n = 39) Sprague-Dawley rats were randomly divided into early (3-day delay) or delayed (14-day delay) ACLR surgery groups, and to receive ALM therapy or saline. During ACLR, an ALM or saline intravenous 1-hour infusion was commenced before first incision, and an intra-articular bolus of ALM or saline was administered at surgery end. Animals were monitored to 28 days postoperatively, and pain, functional recovery, inflammation and joint tissue repair markers, and histopathology were assessed.

In the first postoperative week, delayed ACLR was associated with a lymphocyte-driven immune response, with less systemic inflammation compared with early ACLR. This response was associated with faster recovery of body weight, and less joint pain and swelling in both sexes. At 28 days postoperatively, graft and adjacent joint tissue healing appeared more advanced in females than males, regardless of surgical timing. In both sexes, ALM blunted synovial levels of inflammatory mediators (tumor necrosis factor–α and interleukin-1β), reduced injury markers in articular cartilage, and improved graft healing, evidenced from increased expression of tissue repair markers and bony ingrowth at the graft-tunnel interface.

Delayed versus early ACLR improves joint recovery, and ALM further augments healing by blunting the early immunoinflammatory response in both sexes, irrespective of surgical timing.

Delaying ACLR has the advantage of reducing the pre- and postoperative joint inflammatory environment, with improved outcomes. Perioperative ALM therapy may augment joint healing in both sexes after ACLR.

An age-dependent increase in cellular senescence has been identified in rotator cuff tears (RCTs). The senolytic combination of dasatinib and quercetin (DQ) has been demonstrated to alleviate musculoskeletal diseases by mitigating age-related senescence. However, the effects of DQ treatment on tendon-to-bone healing remain unknown.

To investigate whether DQ treatment can enhance tendon-to-bone healing by reducing age-related senescence in an aged rat model.

Controlled laboratory study.

First, 8 young adult (6-month-old) and 8 aged (24-month-old) rats with sham or RCT surgery were categorized into 4 groups: young sham, young RCT, aged sham, and aged RCT. Four weeks after surgery, the p21 expression of the supraspinatus-humerus complexes was evaluated. Next, 12 young adult and 24 aged rats with chronic RCT underwent repair surgery and were categorized into 3 groups: young (administered vehicle treatment), aged (administered vehicle treatment), and aged + DQ (administered DQ). Twelve weeks after repair, the gene expression and histological and biomechanical properties of the supraspinatus-humerus complexes were evaluated.

Aged rats demonstrated significantly higher p21 expression compared with young adult rats, and RCT surgery further enhanced p21 expression. The aged + DQ group demonstrated a significant decrease in the gene expression of senescence markers (p21 and p16) and senescence-associated secretory phenotype factors (IL-6, IL-1β, and MMP-3) compared with the aged group. Conversely, this group showed upregulation of both chondrogenic (Acan and Col2a1) and tenogenic (Col1a1, Tnmd, and Scx) genes. Histological analysis revealed that the aged + DQ group had decreased cellular senescence and improved cartilage and collagen development at the tendon-to-bone enthesis, with a higher histological score than the aged group. In addition, biomechanical testing indicated that the aged + DQ group had a higher failure load, stiffness, and stress than did the aged group.

DQ treatment significantly alleviated age-related cellular senescence in the rotator cuff enthesis and enhanced tendon-to-bone healing in aged rats.

The senolytic combination of DQ could potentially provide effective clinical therapy for the treatment of RCT in older patients.

To date, no targeted pharmacological agents have been clinically available specifically for postoperative management after anterior cruciate ligament reconstruction (ACLR).

To elucidate the role of macrophage senescence in the tendon-bone interface microenvironment and assess whether targeting CD14 can mitigate senescence, thereby enhancing tendon-bone healing.

Controlled laboratory study.

A murine ACLR model was used to evaluate the tendon-bone healing. Healing was assessed 8 weeks postsurgery through histological staining, micro–computed tomography analysis of neoplastic bone formation within bone tunnels, and biomechanical testing of tendon grafts. Cellular senescence was evaluated using β-galactosidase staining, while immunofluorescence and immunohistochemistry were used to analyze protein expression levels. Macrophage heterogeneity at the tendon-bone interface was assessed via t-distributed stochastic neighbor embedding projection, and senescent macrophage characteristics were investigated using CellChat, KEGG, and GO analyses. Alkaline phosphatase and Alizarin Red S staining were used to evaluate osteogenic differentiation of bone marrow mesenchymal stem cells.

Early inflammatory responses triggered by apoptotic cells at the tendon-bone interface resulted in macrophage senescence, activation of inflammatory pathways, increased secretion of pro-inflammatory factors, and elevated CD14 expression. Targeting CD14 reduced macrophage senescence and the inflammatory response at the tendon-bone interface, thereby increasing tendon-bone healing.

The findings indicate that excessive inflammation within the tendon-bone interface microenvironment promotes macrophage senescence, thereby impairing tendon-bone healing. Targeting CD14 effectively prevents macrophage senescence, facilitating improved tendon-bone healing.

Currently, targeted therapeutics to enhance tendon-bone healing post-ACLR are lacking in clinical practice. The findings demonstrate that microenvironmental inflammation leading to macrophage senescence is a critical factor contributing to impaired tendon-bone healing. CD14-targeted therapy may inhibit macrophage senescence, accelerate tendon-bone healing, and offer significant translational potential for clinical application.

As the number of hip arthroscopy cases performed annually continues to rise, so does the number of patients requiring revision surgery. Determining the cause of failed hip arthroscopy (HA) can be challenging, with residual femoroacetabular impingement (FAI) being the most common indication for revision. While addressing impingement during primary HA is critical, factors such as articular cartilage defects, labral pathology, and capsular management also influence outcomes.

To evaluate trends in revision hip arthroscopy indications at a single institution and assess whether outcomes differ by the primary indication for revision.

Case series; Level of evidence, 4.

A single-center hip preservation registry was reviewed to identify patients who underwent revision hip arthroscopy for FAI between 2012 and 2019. Patient demographics and primary indications for revision hip arthroscopy were determined, and patient-reported outcomes were collected preoperatively and at a mean follow-up of 5.2 years postoperatively.

A total of 173 patients met inclusion criteria for this study. The top 4 primary indications for revision were as follows: residual FAI, 67.8%; capsular instability, 14.6%; heterotopic ossification, 4.6%; and adhesions, 4.2%. Trends in indication did not vary over time. On average, patients significantly improved pre- to postoperatively in the modified Harris Hip Score (21.7; 95% CI, 18.6-24.7), Hip Outcome Score (HOS)–Activities of Daily Living (15.3; 95% CI, 12.1-18.5), HOS–Sport-Specific Subscale (24.1; 95% CI, 19.2-29.1), and International Hip Outcome Tool–33 (30.7; 95% CI, 26.6-34.9; P < .001). Rates of achieving the minimal clinically important difference varied from 67.2% to 82.1%, the substantial clinical benefit from 41% to 56%, and the substantial clinical benefit by absolute value at final follow-up from 45% to 64.8%. In the subgroup analysis, significantly lower preoperative function was noted in the capsular instability cohort when compared with the impingement cohort, as measured by only the HOS–Sport-Specific Subscale (P = .004). Postoperatively, the capsular instability cohort demonstrated significantly worse outcomes as measured by the International Hip Outcome Tool–33 (P = .018), HOS–Activities of Daily Living (P = .015), and modified Harris Hip Score (P = .024). However, there was no significant difference in the net change in pre- to postoperative patient-reported outcome scores when the different indications for revision HA were compared. The rate of re-revision arthroscopy was 6.4%, and 6.9% of patients converted to total hip arthroplasty at a mean age of 40 years.

The most common indication for revision hip arthroscopy in the treatment of femoroacetabular impingement remains residual impingement. Capsular instability has significant consequences for function and may represent a subset of patients who demonstrate more dysfunction before and after revision arthroscopy.

Only a few studies have explored return to recreational sport activity after arthroscopic microfracture for full-thickness acetabular lesions.

Recreational athletes undergoing acetabular microfracture, in addition to general hip arthroscopy procedures, would not achieve similar sport activity to recreational athletes undergoing hip arthroscopy without microfracture at the 5-year follow-up.

Cohort study; Level of evidence, 3.

A retrospective review was conducted of a prospectively collected multicenter hip arthroscopy database of patients undergoing acetabular microfracture for full-thickness chondral lesions. Inclusion criteria were patients between 18 and 50 years of age who had participated in recreational sports before surgery, a diagnosis of femoroacetabular impingement, arthroscopic microfracture for full-thickness chondral lesion, labral repair, complete clinical patient-reported outcomes (PROs), radiographic measurements, and at least 5 years of postoperative follow-up. For each patient included in the study, 1 patient without chondral damage was paired at a 1:1 ratio based on age and sex. The following were assessed: radiographic evaluation, primary preoperative sport, Tegner activity scale score, self-administered Hip Outcome Score (HOS) questionnaire with Activities of Daily Living Subscale (ADL) and Sports-Specific Subscale (SSS) scores, and self-administered short version of the 12-item International Hip Outcome Tool (iHOT-12) score. Clinical relevance was measured using the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB).

A total of 33 patients met the inclusion criteria and were matched with 33 patients without chondral damage. There were no patients lost to follow-up. Both groups showed significant improvement from preoperative PROs to 5-year follow-up. There was no difference in the frequency of patients achieving the MCID, PASS, and SCB for PROs. Return to sport at the 5-year follow-up was similar between groups. Sixteen patients (66.7%) in the microfracture group changed the type of sport they participated in, compared with 9 patients (34.6%) in control group; this difference was statistically significant. The Tegner activity scale score decreased significantly in both groups, but there was no difference between them.

Recreational athletes with full-thickness chondral lesions treated with arthroscopy acetabular microfracture experienced similar return to play to recreational athletes without chondral lesions at the 5-year follow-up. However, a statistically significantly higher rate of athletes in the microfracture group changed the type of sport they participated in.

Labral reconstruction using various graft materials, including autografts and allografts, is gaining popularity to address labral deficiencies. However, the biomechanical effects of graft size, type, and fixation techniques remain underexplored.

The purpose was to evaluate the effects of graft size, graft type, tubularization, and anchor number on suction seal force and distractive stability in an ovine hip model. It was hypothesized that larger graft sizes and the use of allografts would improve the suction seal force and distractive stability compared with smaller grafts and fewer anchor numbers, while tubularization would have no significant effect.

Controlled laboratory study.

A total of 40 sheep hip joints were randomly assigned to 5 groups. Labral excision was performed, followed by reconstruction using autografts or allografts. Ovine extensor tendons were chosen as autografts, whereas labrums from a different ovine hip were used for allografts. For group 1, autografts matching the original labral width were used. For group 2, autografts twice the original labral width were used. For group 3, allografts matching the original labral width were harvested from a different ovine hip. For group 4, autografts matching the original width were fixed with only 2 anchors. For group 5, autografts matching the original width were tubularized before use.

Suction seal force was measured before and after reconstruction using an electromechanical testing system. Statistical analyses included Mann-Whitney U and Wilcoxon signed-rank tests (P < .05).

Group 2 showed the highest improvement in suction seal force, outperforming all other groups (P < .01). Group 4 exhibited the lowest distractive stability among all groups. Tubularization (group 5) did not enhance biomechanical performance (P = .752). Group 3, reconstructed with an allograft, exhibited suction seal performance most closely approximating that of group 2, with no significant difference between them.

The data from the ovine cadaveric model indicate that increasing the graft size enhances the suction sealing force; however, it remains below the measurements observed in an intact labrum. Furthermore, increasing the number of anchors and optimal graft selection improve postoperative biomechanical stability.

Optimizing graft size and fixation techniques in labral reconstruction may improve joint stability and suction seal function and may support surgical strategies aimed at improving outcomes and delaying the progression of osteoarthritis in patients with labral defects.

Shoulder stiffness after arthroscopic rotator cuff repair (RCR) is associated with a prolonged rehabilitation process and impaired functional outcomes. Previous studies have demonstrated that metformin can alleviate joint stiffness in animal models. However, its clinical effectiveness and safety require further confirmation in clinical practice.

The purpose of this study was to investigate whether 3 months of postoperative treatment with metformin, compared with placebo, reduced the incidence of shoulder stiffness in patients after arthroscopic RCR. It was hypothesized that the postoperative administration of metformin would decrease the risk of postoperative shoulder stiffness.

Randomized controlled trial; Level of evidence, 1.

A total of 146 consecutive patients with rotator cuff tears were randomly assigned to receive a 500-mg dose of metformin or placebo twice daily for 3 months after arthroscopic RCR. The primary outcome was the incidence of shoulder stiffness at 3 months’ follow-up. Secondary outcomes included the American Shoulder and Elbow Surgeons (ASES) score, pain, and patient satisfaction during the first postoperative year as well as concentrations of plasma fibrotic biomarkers at 3 months’ follow-up. The primary and secondary outcomes were measured at baseline and 3 months, 6 months, and 1 year postoperatively. Safety was assessed by adverse events, and rotator cuff tendon healing was evaluated by ultrasonography.

Complete outcome measurements were obtained for 126 patients. There were 64 participants in the metformin group and 62 in the control group. The incidence of shoulder stiffness was significantly lower in the metformin group than in the control group at 3 months postoperatively (11% vs 27%, respectively; risk ratio, 0.40 [95% CI, 0.18-0.90]; P = .02). There was no significant difference regarding ASES, pain, and satisfaction scores between groups at 1-year follow-up. The concentrations of plasma fibrotic biomarkers were significantly lower in the metformin group than in the control group. The tendon healing rates were comparable between the 2 groups at final follow-up (risk ratio, 0.97 [95% CI, 0.86-1.10]; P = .83).

Metformin treatment reduced the incidence of shoulder stiffness after arthroscopic RCR. Metformin did not negatively influence rotator cuff tendon healing. These findings indicated that metformin is a potential pharmacological prophylaxis for postoperative shoulder stiffness.

Chinese Clinical Trial Registry (ChiCTR2300074329)

Arthroscopic Bankart repair (ABR) is one of the most common arthroscopic surgeries for recurrent dislocation of the shoulder. A few previous studies have reported anchor hole enlargement after ABR. All-soft suture anchors (ASSAs) and biodegradable anchors (BDAs) have been mainly used recently; however, to the authors’ knowledge, no reports are available that compare anchor hole enlargement between ASSAs and BDAs over a 2-year follow-up period.

To compare the changes in anchor hole diameter between ASSAs and BDAs.

Cohort study; Level of evidence, 3.

The anchor holes of 61 patients who underwent ABR for anterior shoulder instability were analyzed. The changes in anchor hole diameters were evaluated by 3-dimensional computed tomography performed immediately after surgery and at 6, 12, and 24 months postoperatively. The diameter enlargement ratio was calculated by dividing the diameters at 6, 12, or 24 months by their counterparts immediately postoperatively and was classified into enlargement (ratio >1.5), mild enlargement (1.1-1.5), no change (0.9-1.1), or reduction (<0.9). Furthermore, all anchors were divided into 2 groups—ASSA group and BDA group—to evaluate the effect of the anchor types on the anchor hole diameter changes. The differences between preoperative and postoperative results were compared using paired t test, Mann-Whitney U test, or Fisher exact test. The differences in hole enlargements between the time points were analyzed using the Kruskal-Wallis test.

In total, 315 holes (232 ASSAs, 45 shoulders; 83 BDAs, 17 shoulders) were available for assessment. Among the overall holes, proportions of enlargement and mild enlargement at 6, 12, and 24 months were 8.3%, 8.0%, and 8.8% and 27.0%, 18.2%, and 16.9%, respectively. The anchor hole enlargement was observed in 35.4% of the ASSA group and 34.9% of the BDA group at 6 months compared with those immediately after surgery. The mildly enlarged anchor holes significantly decreased after 12 months in the ASSA group (26.3%, 15.3%, and 17.8% at 6, 12, and 24 months, respectively), whereas no significant decrease was observed in the BDA group (28.9%, 26.0%, and 17.4% at 6, 12, and 24 months, respectively). The enlarged anchor holes significantly decreased after 12 months compared with those immediately after surgery in the ASSA group (9.1%, 7.4%, and 6.7% at 6, 12, and 24 months, respectively) but did not decrease at 12 or 24 months in the BDA group (6.0%, 9.6%, and 10.9% at 6, 12, and 24 months, respectively).

Enlarged anchor holes were decreased with ASSAs but not with BDAs. Enlarged anchor holes could be reduced over a longer observation.

Distal tibial allograft (DTA) is the most widely used allograft for glenoid reconstruction, but distal radius allograft (DRA) has been proposed as a novel graft option with the advantage of providing a more acute radius of curvature in the anterior-posterior plane that is closer to the native glenoid.

To utilize a biomechanical testing model to investigate the glenohumeral contact pressure and kinematics of DRA versus DTA reconstructions of anterior glenoid bone loss.

Controlled laboratory study.

A total of 11 human cadaveric upper extremities and 11 ankle specimens were utilized. A 30% defect of the anterior glenoid was created and reconstructed with DRA or DTA. A robotic testing system was used to test native joint, DRA, and DTA reconstructions at 60° and 90° of abduction from 0° to 90° of external rotation. Measurements of the center of rotation and humeral head translation were captured using a motion tracking camera. Load and torque data were recorded using a 6-axis load cell. Pressure and contact area were recorded with a pressure mapping sensor pad between the humeral head and the glenoid.

No significant differences were observed in contact pressure, contact area, translation, load, or torque between the native and allograft reconstruction conditions at 60° or 90° of abduction. No significant differences were found in contact pressure, contact area, translation, load, or torque between the DRA and DTA reconstruction conditions at 60° or 90° of abduction.

The biomechanical data showed comparable compressive forces and glenohumeral joint kinematics between the native joint, DRA, and DTA reconstructions for large anterior glenoid bone loss defects.

These biomechanical data suggest that DRA represents a promising option for reconstruction of large anterior glenoid bone loss defects. The findings warrant further investigation into the variability of distal radius morphology and future clinical evaluation of DRA reconstruction in the setting of critical glenoid bone loss.

Anterior shoulder instability (ASI) is often seen in both contact and noncontact athletes, and the arthroscopic Bankart repair (ABR) procedure is among the most utilized procedures to treat patients with this condition. There is a lack of large studies comparing the return to sport (RTS), outcome, and recurrence rates after ABR in contact and noncontact athletes.

To understand the differences in postoperative RTS, outcomes, and complications in contact and noncontact athletes after primary ABR for ASI.

Systematic review and meta-analysis; Level of evidence, 4.

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies reported primary ABR without remplissage to treat ASI in athletes with a 1-year minimum follow-up. Random-effects meta-analysis was performed to compare outcomes.

Of the 1575 screened studies, 31 studies (2387 shoulders) were included. The mean age was 23.3 years (range, 13-50 years; SD, 2.97 years), 89% of the athletes were male, and the mean follow-up was 55.1 months (range, 12-107 months; SD, 22.8 months). Contact and noncontact athletes had similar rates of RTS (79% [95% CI, 63%-89%] and 91% [95% CI, 82%-96%], respectively; P = .079) and return to preinjury level (71% [95% CI, 56%-82%] and 79% [95% CI, 73%-85%], respectively; P = .201). Contact and noncontact athletes also demonstrated similar rates of revision surgery (6% [95% CI, 3%-13%] and 4% [95% CI, 3%-7%], respectively; P = .334). Contact athletes, however, exhibited a significantly higher rate of recurrent instability than noncontact athletes (17% [95% CI, 10%-27%] vs 8% [95% CI, 6%-12%]; P = .023).

Compared with noncontact athletes, contact athletes demonstrate similar rates of RTS, return to preinjury level of play, and need for revision surgery but a higher rate of recurrent instability after primary ABR for ASI.

Currently, there is no uniform rehabilitation program concerning mobilization after a distal biceps tendon repair. A systematic review was conducted to investigate the effect of restrictions within the immediate postoperative period to evaluate clinical outcomes relative to mobilization after surgical repair of complete distal biceps tendon tears.

Early mobilization will not have a significant difference on outcomes compared with delayed mobilization.

Meta-analysis; Level of evidence, 3.

The authors performed a systematic review in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines of studies reporting outcomes of the distal biceps tendon repair. The early mobilization cohort included studies with no restrictions beyond 2 weeks after surgery, and the delayed mobilization cohort included studies with continued restrictions beyond 2 weeks after surgery.

A total of 26 studies with 1114 patients (643 in the delayed mobilization cohort and 471 in the early mobilization cohort) met the inclusion criteria, with a weighted mean patient age of 45.14 years (range, 18-76 years) and a mean follow-up of 27.9 months (range, 3-120 months). Meta-analysis at the 24-month follow-up found that range of motion (ROM) was not significantly different across early and delayed mobilization cohorts for flexion (mean, 137.38° vs 140.42°; P = .34) and extension (mean, 3.23° vs 1.5°; P = .91). Early mobilization was found to be significantly associated with less pronation (mean, 75.68° vs 83.18°; P = .0019) and supination (mean, 76.38° vs 83.93°; P = .0049). Analysis of patient-reported outcomes (PROs) found that Disabilities of the Arm, Shoulder and Hand scores (mean, 3.93 vs 4.21; P = .77) and Mayo Elbow Performance Score values (mean, 96.33 vs 97.11;P = .65) were not significantly different across cohorts. Failure analysis found a significant difference when comparing proportion (mean, 0.0006 vs 0.0185; P = .0029) but no difference when comparing incidence rate (mean, 0.0001 vs 0.0001; P = .647). Complication analysis found no statistical difference in proportion (mean, 0.2181 vs 0.1918; P = .7388) or incidence rate (mean, 0.0012 vs 0.008; P = .344).

These results suggest there may be no clinically significant difference in failure rates, complications, ROM, or PROs for early versus delayed mobilization after primary distal biceps tendon repair.

Management of symptomatic osteochondral defects of the knee remains challenging because of the limited inherent vascularity and healing potential of articular cartilage. Osteochondral allograft (OCA) transplantation has yielded satisfactory results in appropriate patients; however, the effect of OCA transplantation on athletes seeking to return to sport (RTS) remains largely unknown.

To systematically review the literature to better understand outcomes after OCA, focusing on RTS rate and timing, and the incidence of postoperative complications.

Systematic review; Level of evidence, 4.

Studies included in the PubMed, EMBASE, and Cochrane Library databases from inception to August 2024 that reported on athletes participating at the recreational, high school, collegiate, and professional levels undergoing OCA transplantation for osteochondral defects in the knee were identified. Inclusion criteria included studies reporting on patients identified as athletes undergoing OCA transplantation with reported origin, lesion characteristics (size and location), RTS rate and timing, complications, reoperations, and patient-reported outcomes.

A total of 14 studies, consisting of 471 athletes undergoing OCA transplantation with a weighted mean follow-up of 51.1 months, were identified. The weighted mean patient age was 31.4 years (range, 15-69 years), with 61% of patients being male. Lesion origin was reported in 49% (230/471) of patients, with osteochondritis dissecans (OCD) reported in 44% (100/230). The medial femoral condyle was the most common defect location (44%; 68/153). Lesion size ranged from 1 to 13.94 cm². Sixteen percent (75/471) of patients were classified as competitive athletes, with basketball (n = 21) being the most common sport. RTS was reported in 72% (338/468) of patients, with 84% (231/275) returning at an equal or higher level of play at a weighted mean of 11.1 months (range, 6-26 months) after OCA. Complications were reported in 12% (41/351) of patients, with graft failure accounting for 54% (22/41) of complications in 6% (22/351) of patients.

For athletes undergoing OCA transplantation to the knee, OCD was the most commonly reported cause, with the medial femoral condyle most frequently affected. Successful RTS was reported in 72% of patients at a mean of 11.1 months, with graft failure representing the most common complication in 6%.

Accurate femoral tunnel positioning is essential for successful anterior cruciate ligament (ACL) reconstruction. Tunnel malposition can happen due to limited arthroscopic visibility as well as anatomic variance. The use of customized patient-specific guides can optimize surgical planning and enhance accuracy.

To compare femoral tunnel positioning in 3-dimensional (3D)-assisted ACL reconstruction versus conventional surgery.

Systematic review and meta-analysis; Level of evidence, 3.

This systematic review and meta-analysis was performed in line with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines with a search of the following databases: MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. All randomized controlled trials (RCTs) and observational studies comparing the 2 interventions were included. Primary outcomes included tunnel positioning time (minutes) and accuracy rates (%). Secondary outcomes were Lysholm and International Knee Documentation Committee (IKDC) functional scores. Random effects modeling was used for analysis.

Four RCTs and 1 retrospective study were included, enrolling a total of 299 patients. The 3D group had significantly shorter tunnel positioning times (mean difference, –2.80; 95% CI, –4.13 to −1.46; P < .0001) with significantly greater tunnel positioning accuracy (odds ratio, 4.62; 95% CI, 1.02 to 20.89; P = .05). No significant difference was noted in postoperative functional scores, including Lysholm and IKDC scores (P > .05).

The use of 3D guides helps reduce tunnel positioning time and increases tunnel positioning accuracy with comparable postoperative functional outcomes.

Return to sport (RTS) is a common goal after anterior cruciate ligament (ACL) reconstruction (ACLR) but carries a relatively high risk of reinjury with up to 20% to 25% of athletes experiencing graft rupture or contralateral ACL tear. While there is increased emphasis on establishing safe RTS criteria for athletes to return to previous activity levels, studies show that even healthy individuals have difficulty passing RTS testing.

To synthesize data concerning whether healthy individuals can pass ACLR RTS rehabilitation tests.

Systematic review; Level of evidence, 4.

Following the established PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors conducted a systematic literature search in May 2023. Three databases were used in the search (PubMed, EMBASE, and SPORTDiscus) to retrieve all studies that conducted ACLR RTS rehabilitation tests on healthy individuals. Tests included were isometric strength, isokinetic strength, hop, and balance tests. The search was performed in duplicate, and a quality assessment of all studies was included.

A total of 1724 studies were retrieved, of which 32 were included, involving 1552 controls with no history of ACL injury. From the studies analyzed, 5.3% to 42.2% of healthy participants failed 6 different hop tests, 15.2% failed the Star Excursion Balance Test, 37% failed the isometric knee flexion test, 50% failed the isometric knee extension test, and 23.7% to 28.9% failed the drop vertical jump test. An asymmetry index ≥10% was found in 6 of the 18 isokinetic tests and 2 of the 14 isometric tests. Hop testing was the most common test in the included studies (56.3%), followed by balance testing (31.3%), isometric strength testing (31.3%), isokinetic strength testing (25%), and drop vertical jump (6.3%).

Many healthy individuals fail ACLR RTS tests, with some having an inherent variation from side to side that is >10%. The passing threshold for RTS testing should be a value that is practical yet helps reduce reinjury rates.