Localized Anterior Arthrofibrosis After Soft-Tissue Quadriceps Tendon Anterior Cruciate Ligament Reconstruction Is More Common in Patients Who Are Female, Undergo Meniscal Repair, and Have Grafts of Larger Diameter

Sports Injuries in Female and Non-Binary Athletes: A Systematic Review

PURPOSE OF REVIEW

The main purpose of this review was to summarize the current evidence on treatment and outcomes of sports injuries requiring surgical intervention in female and non-binary athletes and identify key gaps in the related literature concerning sports injuries requiring surgical intervention to guide future research.

RECENT FINDINGS

Of the 59 included studies, all focused on biological sex or sex-based differences, while none of the studies discussed gender or the inclusion of non-binary and transgender individuals. Most of the studies (47/59, 80%) focused on ACL reconstruction (37%), hip arthroscopy (27%) or rotator cuff repair (15%). Important sex-based differences were seen with these injuries including differences in fears regarding recovery after ACL injury and pre- and post-operative pain scores following rotator cuff injury. Despite increasing recognition of the role of biologic sex in the treatment and outcomes of sports injuries, very little is known about the impact of gender in sports injuries. Previous sociological literature suggests that gender may play an important role in one's athletic experience, and thus their injury experience. With most of the included studies focused on only three injury types, the experiences of female and non-binary athletes with all other sports injuries are poorly characterized. The lack of gender-inclusive sports injuries research means that the complete experiences of female, non-binary and transgender athletes are not comprehensively captured in the current literature. Future research should aim to characterize the effect of gender on the treatment and outcomes on all sport-related injuries, with the goal of providing inclusive surgical care for all athletes.

Trends in Complications Following Pediatric Anterior Cruciate Ligament Reconstruction as Reported to the American Board of Orthopaedic Surgery Part II Oral Examination Database

Background

Pediatric anterior cruciate ligament reconstructions (ACLR) have increased dramatically in recent years. However, a comprehensive list of short-term complications related to this procedure has yet to be reported. This study aimed to report complication rates in pediatric ACLR using submissions to the American Board of Orthopaedic Surgery (ABOS) Part II Oral Examination. A secondary goal was to assess the relationship of complications with patient sex, geographic region of surgery, surgical volume, and surgeon fellowship training.

Methods

A query was submitted to the ABOS Part II Oral Examination Case List Database for all ACLR performed in patients younger than 19 years between 2000 and 2021. Surgeon fellowship training, geographic region of surgery, and patient demographics were included, along with medical, surgical, and anesthetic complications, reoperation, and readmission. Statistic comparisons used chi-square tests for categorical variables with significance set at P < 0.05.

Results

Surgical complications were the most common type of complication, present in 10.1% of pediatric ACLR. Stiffness (3.6%) and infection (1.5%) were the most prevalent surgical complications. Females had higher rates of overall complications than males (11.9% vs. 10.4%, P = 0.010). Females also had higher rates of surgical complications (10.7%-9.5%, P = 0.019) -- specifically stiffness (5.0%-2.2%, P < 0.001). However, males had higher rates of infection (1.8% vs. 1.3%, P = 0.047). Geographic analyses showed higher infection rates in Hawaii and Alaska and lower surgical complication rates in the Northwest region. Procedures completed by surgeons with a fellowship training other than Sports Medicine and/or Pediatric Orthopaedics had lower rates of overall complications (8.9%, P < 0.001) and surgical complications (8.3%, P < 0.001).

Conclusion

This study establishes that female pediatric and adolescent patients are at an increased risk for complications following ACLR. Arthrofibrosis was more than twice as common in females than in males. Geographic region and fellowship training may be associated with complications in this population.

Study design

Cross-Sectional Study.

Key Concepts

(1)Complications following ACL reconstruction may be associated with geographic region and fellowship training.(2)Females present with more short-term complications following ACL reconstruction.(3)There was a higher reported infection rate overall for surgeons in their board collection period than infection rates in the literature, with males having an overall higher infection rate than females.(4)Arthrofibrosis is more than twice as common in females than males following ACL reconstruction.

Level of Evidence

III.

Loss of Knee Extension Anterior Cruciate Ligament Reconstruction With Quadriceps Tendon Autograft

Background

Primary anterior cruciate ligament reconstruction (ACLR) using quadriceps tendon (QT) autograft may increase the risk for postoperative loss of extension, although it is unclear if this is due to QT autograft diameter.

Purpose

To document the rate of >5° loss of knee extension after QT autograft ACLR and determine associations between loss of extension, QT autograft diameter, and notch volume.

Study Design

Case-control study; Level of evidence, 3.

Methods

A retrospective review of a consecutive series of patients undergoing primary ACLR with QT autograft between January 2014 and December 2021 by 7 fellowship-trained orthopaedic surgeons at a single health care institution was performed. Patients with revision ACLR, multiligamentous knee surgery, concomitant cartilage procedures, <14 years of age, unavailable preoperative magnetic resonance imaging (MRI), or <6 months of follow-up were excluded. Loss of extension was defined using the International Knee Documentation Committee criteria for abnormal knee extension (>5° loss of extension compared with the contralateral knee) 3 to 12 months after ACLR, or any subsequent surgery for loss of extension. Patients who were unable to achieve terminal knee extension (defined as 0° of extension irrespective of the contralateral knee) were also identified and analyzed. Notch volume was measured by 2 observers using preoperative MRI scans, and a ratio of QT autograft diameter to notch volume was calculated. Univariate and multivariate analyses were performed to assess factors associated with postoperative loss of extension.

Results

A total of 500 patients were identified, of whom 333 (67%) were included (mean age, 22.8 ± 7.7 years; 151 [45%] female). The mean follow-up was 1.6 ± 1.3 years (range, 0.5-9.5 years). The rate of postoperative loss of extension was 11% (n = 37), and 70% (26/37) of those with loss of extension underwent a subsequent surgery to restore extension (mean, 1.1 ± 1.2 years postoperatively). There was no difference in QT autograft diameter (9.5 mm vs 9.6 mm; P = .81), notch volume (6.3 cm3 vs 6.5 cm3; P = .70), and the ratio between QT autograft diameter and notch volume (1.6 vs 1.6; P = .75) between patients with and without postoperative loss of extension. No differences were found in preoperative (P = .62) and postoperative (2-4 months [P = .99]; 5-8 months [P = .71]; ≥9 months [P = .95]) extension between patients with a QT autograft diameter ≥10 mm and <10 mm. Only the inability to achieve terminal extension (0°) at the initial preoperative visit was associated with postoperative loss of extension on multivariate analysis (OR, 2.23 [95% CI, 1.10-4.58]; P = .03).

Conclusion

Eleven percent of patients undergoing QT autograft ACLR experienced a loss of >5° knee extension compared with the contralateral knee or required additional surgery to restore extension. QT autograft diameter and notch volume were not associated with postoperative loss of extension among patients who underwent primary QT autograft ACLR. The inability to achieve terminal extension (0°) at the initial preoperative presentation increased the risk of postoperative loss of extension by 2.23-fold. Surgeons may consider the lack of terminal extension preoperatively as a risk factor for postoperative loss of extension following QT autograft ACLR rather than increased QT autograft diameter or decreased notch volume.

Editorial Commentary: Failure to Regain Full Hyperextension After Anterior Cruciate Ligament Reconstruction Is Associated With Inferior Patient Satisfaction and Lower Functional Outcomes Scores, But the Impact on Graft Rupture Rates and Persistent Instability Is Unclear

Up to one half of patients undergoing anterior cruciate ligament reconstruction demonstrate some degree of knee hyperextension in their contralateral limb. In most cases, this is mild (1°-5°), but it is reported that 9% and 0.8% demonstrate moderate (6°-10°) and severe (>10°) degrees of hyperextension. These characteristics pose challenges and considerations for surgical management. This includes the finding that failure to regain full hyperextension is common and is associated with inferior functional outcomes and patient satisfaction, and the juxtaposition that regaining full hyperextension may increase graft rupture and persistent instability rates. Although the pathophysiology of extension deficit is multifactorial, 2 particularly important and modifiable risk factors in this population are notch impingement and arthrogenic muscle inhibition. Strategies to avoid notch impingement include anterior notchplasty and careful consideration of graft size, graft type, and tibial tunnel placement. Arthrogenic muscle inhibition is clinically characterized by extension deficit and quadriceps activation failure. It is reversible in most patients and therefore an important modifiable risk factor. Since failure to regain full hyperextension is associated with inferior outcomes, abolishing extension deficit should be a key objective of surgical treatment and rehabilitation. Concerns regarding the risks of persistent laxity and graft rupture in knee hyperlaxity/hyperextension patients can be mitigated by the addition of anterolateral ligament reconstruction.

Magnetic Resonance Imaging Can Predict Hamstring or Quadriceps Tendon Autograft Diameter in Pediatric or Adolescent Anterior Cruciate Ligament Reconstruction: A Systematic Review

OBJECTIVE

Insufficient graft diameter is an important factor that contributes to failure rates after anterior cruciate ligament reconstruction (ACLR). Although modalities, such as magnetic resonance imaging (MRI), have been well investigated in the adult population to predict graft diameter preoperatively, it is unclear whether similar strategies can be used in the pediatric population. This review aims to evaluate the utility of MRI in the preoperative estimation of autograft parameters in pediatric or adolescent patients undergoing ACLR.

METHODS

Three databases were searched on January 31, 2024. The authors adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Revised Assessment of Multiple Systematic Reviews guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, graft characteristics, MRI imaging techniques, and statistical analyses correlating MRI parameters with graft length or diameter were recorded.

RESULTS

Five studies consisting of 450 patients were included in this review (48.4% females). The mean (SD) age at ACLR was 14.7 (6.8) years. Three studies using hamstring tendon (HT) autografts found that combined semitendinosus and gracilis tendon cross-sectional area (ST+GT CSA) were able to predict graft diameter. One study reported an ST+GT CSA cutoff of 31.2 mm 2 to have an 80% and 74% sensitivity and specificity, respectively, in predicting HT autograft diameter above 8 mm. Two studies using quadriceps tendon (QT) autografts found that tendon thickness on sagittal MRI view was able to predict graft diameter. One study reported a QT cutoff of 6.7 mm to have 97.5% and 46.6% sensitivity and specificity, respectively, in predicting the diameter of the QT graft to be above 8 mm. Associations between MRI parameters and graft length were not reported.

CONCLUSION

Although there is limited evidence, ST+GT CSA and QT thickness on sagittal view on MRI can be used to predict intraoperative HT and QT autograft diameter, respectively, in pediatric or adolescent ACLR. Future investigations should investigate correlations between imaging parameters and graft length, especially when using QT autografts in the pediatric population.

LEVEL OF EVIDENCE

Level III.

Comparison of Arthrofibrosis After ACL Reconstruction According to Graft Choice: Quadriceps Tendon Versus Bone-Patellar Tendon-Bone Autograft

Background

Arthrofibrosis is a complication of anterior cruciate ligament reconstruction (ACLR), and it is possible that graft choice such as the quadriceps tendon (QT) autograft may be a risk factor. With the increasing popularity of the QT autograft, it is important to compare it with other graft choices.

Purpose/Hypothesis

The purpose of this study was to identify whether graft choice, QT versus bone-patellar tendon-bone (BTB) autograft, is a risk factor for early return to the operating room for arthrofibrosis after ACLR. It was hypothesized that the rate of arthrofibrosis surgery would be higher for the QT autograft recipients.

Study Design

Cohort study; Level of evidence, 3.

Methods

A single-center retrospective chart review was conducted between January 2010 and November 2022. Skeletally mature patients who underwent primary ACLR with either QT or BTB autograft were considered for inclusion. Patients who received an alternate graft or those undergoing revision ACLR were excluded. The primary outcome of interest was return to the operating room for arthrofibrosis release (either manipulation under anesthesia or lysis of adhesions).

Results

Of 1726 included patients (1155 receiving a BTB autograft and 571 receiving a QT autograft), 5.2% (n = 60) of BTB recipients and 6.5% (n = 37) of QT recipients required subsequent arthrofibrosis. There was no significant association between graft type and subsequent arthrofibrosis (P = .275). There was a significant association with graft type and presence of a cyclops lesion (65.0% of BTB grafts and 40.5% of QT grafts; P = .018). After removing those patients with chronic tears who underwent ACLR at >1 year, patients who required arthrofibrosis were found to have a significantly shorter time between injury and ACLR (mean, 59.23 ± 48.46 days) than those who did not require arthrofibrosis (mean, 81.7 ± 72.63 days) (P≤ .01). Significantly more female patients (9.25%) than male patients (2.79%) required arthrofibrosis (hazard ratio, 3.82; P < .001), and patients who required arthrosis were significantly younger (mean, 22.52 ± 9.35 years) than those who did not (mean, 25.74 ± 10.83 years) (P = .001).

Conclusion

Study findings indicated no statistically significant difference in the rate of secondary arthrofibrosis surgery between patients who underwent ACLR with either QT or BTB autograft.

Editorial Commentary: Analysis of Practice Patterns and Changes for Anterior Cruciate Ligament Surgery Document the Past and Present, but High-Quality Data Should Inform the Future

Trends in practice patterns for anterior cruciate ligament surgery can give us a real-world look at what surgeons are actually doing. When large institutional studies show changing practice patterns over time, we can use those data to help benchmark our own practices. Innovations are inspired by colleagues, published literature, and industry, and not all innovation is positive. A return to independent drilling of the femoral and tibial tunnels reverses a single-incision trend that was less anatomic. Although hamstring tendon grafts are a popular graft choice, hamstring tendon grafts are associated with greater revision rates, and high-volume surgeons prefer bone-patellar tendon-bone and quadriceps tendon and autografts in general. Additional data are required to determine the benefit of quadriceps tendon and of lateral extra-articular tenodesis augmentation of anterior cruciate ligament reconstruction. Although a first step is to identify current practice patterns, the most important step is to develop high-quality outcome data, which can be used to inform surgeons so they can individualize and optimize surgery for their patients.

Primary All-Soft Tissue Quadriceps Tendon Autograft Anterior Cruciate Ligament Reconstruction With Suture Tape Augmentation Resulted in Satisfactory Patient Outcomes and a Low Graft Failure Rate in High School and Collegiate Athletes

PURPOSE

To evaluate ≥2-year patient outcomes after primary all-soft tissue quadriceps tendon autograft (ASTQ) anterior cruciate ligament reconstruction (ACLR) with suture tape augmentation (STA) in skeletally mature high school and collegiate athletes.

METHODS

All high school and collegiate athletes who underwent primary ASTQ ACLR with STA with a minimum of 2-year follow-up were analyzed retrospectively. Patients were administered validated patient-reported outcome measures (PROMs) pre- and postoperatively. The minimal clinically important difference was calculated for each PROM based on this study population and applied to the individual patient. Return to sport, subsequent surgical intervention including contralateral ACLR, and KT-1000 arthrometer measurements for knee laxity were collected. Complications were assessed by physical examination, radiologic studies, or obtained via telephone.

RESULTS

In total, 60 patients were included in the final data analysis, with a mean age of 16.8 years (95% confidence interval 13-23) and mean final follow-up of 37.1 months (95% confidence interval 33.1-41.1). Twelve patients (20%) required subsequent surgery on the ipsilateral knee, which included 7 patients having a subsequent meniscal procedure and 3 patients who underwent arthrolysis. None sustained a graft failure, and 6 patients sustained a contralateral ACL injury necessitating surgery. All PROMs improved at the final follow-up (P < .001). In addition, KT-1000 arthrometer measurements significantly improved postoperatively at 1-year clinical follow-up (P < .001). Most patients obtained the minimal clinically important difference thresholds for each PROM at the final follow-up. There were 48 patients (80%) who participated in pivoting sports. The return-to-sport rate at same level was 54 patients (90%), with 6 patients (10%) not returning to the same level because of graduation.

CONCLUSIONS

ASTQ ACLR with STA in a young athletic patient population may result in a low graft failure rate while maintaining satisfactory patient outcomes at short-term follow-up, including a return to sport at the same level of 90%.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Quadriceps tendon autograft diameters are routinely above 8 mm, and preoperative size estimation before anterior cruciate ligament reconstruction may not be necessary for this graft type: A systematic review

PURPOSE

To identify values of reported quadriceps tendon (QT) autograft diameter and length in anterior cruciate ligament reconstruction (ACLR), and to identify methods to predict these parameters.

METHODS

A search was conducted across three databases from inception to 30 March 2024. Data on study characteristics, demographics, anthropometric data, imaging techniques, and QT autograft or harvested QT tendon parameters were extracted. Values quantifying the statistical strength of associations between imaging or anthropometric characteristics and graft or tendon parameters as well as for associations between these parameters and postoperative outcomes were recorded.

RESULTS

A total of 3633 patients were included. The weighted mean QT autograft diameter and length were 8.9 (standard deviation [SD]: 0.7, range: 7.8-10.4) mm and 8.1 (SD: 1.3, range: 5.6-9.3) cm, respectively. A total of 93.8% of studies that reported mean QT autograft diameter found a value of 8 mm or greater. The QT groups had similar or significantly greater mean autograft diameter compared to the hamstring tendon (HT) groups in 91.7% of studies that reported significance. Regarding MRI measurements, 71.4% of the correlation coefficients reported showed a moderate positive correlation, 28.6% showed a low positive correlation and 14.3% showed a high positive correlation. Regarding anthropometric characteristics, 33.3% and 16.7%, 16.7% and 14.3% of studies that reported on the relationship between QT autograft diameter and height, weight, body mass index or age, respectively, found a low positive statistically significant correlation. Only statistically nonsignificant associations were reported between QT autograft parameters and post-operative outcomes and complications.

CONCLUSIONS

QT autografts used in ACLR have a mean diameter of 8 mm or greater and are consistently larger than HT autografts. Preoperative MRI measurements are better than anthropometric characteristics at predicting QT autograft parameters; however, preoperative prediction may not be necessary for this graft type. QT autograft parameters were not found to be significantly associated with any post-operative complication or outcome.

LEVEL OF EVIDENCE

Level IV.

Research progress of knee fibrosis after anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) injury is a common sports injury, and ACL reconstruction is an effective surgery for this trauma. Most cases gain good recovery after surgery, while some patients may experience knee stiffness, which is characterized by joint fibrosis, leading to reduced joint mobility, pain, and dysfunction. Currently, various research studies have been conducted to unveil the mechanisms underlying this condition, identifying pre-, intra-, and post-operative risk factors, and testify the efficacy of different therapeutic methods against it. In this review, we summarize the current progress regarding the advancements in knee fibrosis after ACL reconstruction. The risk factors associated with knee fibrosis are systematically delineated, accompanied by an evaluation of the efficacy of various treatment modalities for both the prevention and mitigation of fibrosis. Furthermore, recommendations for future research directions are proposed, offering a foundational basis for subsequent investigations.

The Role of Biomarkers in Predicting Outcomes of Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background

Anterior cruciate ligament (ACL) injury is frequently associated with injuries to other parts of the knee, including the menisci and articular cartilage. After ACL injury and reconstruction, there may be progressive chondral degradation. Biomarkers in blood, urine, and synovial fluid can be measured after ACL injury and reconstruction and have been proposed as a means of measuring the associated cellular changes occurring in the knee.

Purpose

To systematically review the literature regarding biomarkers in urine, serum, or synovial fluid that have been associated with an outcome measure after ACL reconstruction.

Study Design

Systematic review; Level of evidence, 3.

Methods

This review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The MEDLINE, Embase, CINAHL, and Web of Science databases were searched to identify studies published before September 2023 that reported on patients undergoing ACL reconstruction where a biomarker was measured and related to an outcome variable. Of 9360 results, 16 studies comprising 492 patients were included. Findings were reported as descriptive summaries synthesizing the available literature.

Results

A total of 45 unique biomarkers or biomarker ratios were investigated (12 serum, 3 urine, and 38 synovial fluid; 8 biomarkers were measured from >1 source). Nineteen different outcome measures were identified, including the International Knee Documentation Committee Subjective Knee Form, Knee injury and Osteoarthritis Outcome Score, numeric pain scores, radiological outcomes (magnetic resonance imaging and radiography), rates of arthrofibrosis and cyclops lesions, and gait biomechanics. Across the included studies, 17 biomarkers were found to have a statistically significant association (P < .05) with an outcome variable. Serum interleukin 6 (s-IL-6), serum and synovial fluid matrix metalloproteinase-3 (s-MMP-3 and sf-MMP-3), urinary and synovial fluid C-terminal telopeptide of type 2 collagen (u-CTX-II and sf-CTX-II), and serum collagen type 2 cleavage product (s-C2C) showed promise in predicting outcomes after ACL reconstruction, specifically regarding patient-reported outcome measures (s-IL-6 and u-CTX-II), gait biomechanical parameters (s-IL-6, sf-MMP-3, s-MMP-3, and s-C2C), pain (s-IL-6 and u-CTX-II), and radiological osteoarthritis (ratio of u-CTX-II to serum procollagen 2 C-propeptide).

Conclusion

The results highlight several biomarkers that have been associated with clinically important postoperative outcome measures and may warrant further research to understand if they can provide meaningful information in the clinical environment.

Influence of female sex and double-quadruple semitendinosus-gracilis graft on the incidence of postoperative symptomatic cyclops lesions after ACL reconstruction

PURPOSE

Risk factors for the development of symptomatic cyclops lesion after anterior cruciate ligament reconstruction (ACLR) surgery are not entirely identified yet. This study aimed to investigate whether the choice of hamstring graft (semitendinosus-gracilis; STG vs. semitendinosus; ST) affects the risk of developing a symptomatic cyclops lesion after ACLR.

METHODS

This retrospective cohort study included 1416 patients receiving either an ST graft (n = 1209) or an STG graft (n = 207) ACLR with a follow-up of at least 2 years. A persisting extension limitation was clinically determined, and cyclops lesions were confirmed by magnetic resonance imaging (MRI) and second-look arthroscopy. Graft-specific incidence of cyclops lesions was examined with χ2 test and combined with the factors number of graft bundles, graft diameter and sex evaluated with a binominal logistic regression model.

RESULTS

In total, 46 patients developed symptomatic cyclops lesions (3.2%), with 36 having ACLR with an ST graft (3.0%) and 10 with an STG graft (4.8%) (n.s). The mean time from ACLR to the second-look arthroscopy for cyclops removal was 1.1 ± 0.6 years. Female patients were 2.5 times more likely to develop a cyclops lesion than male patients. Patients with an STG graft and larger graft diameters did not have a higher risk of developing cyclops lesions. Patients who received an STG graft with both tendons folded four times (double-quadruple) had significantly higher risk of developing a cyclops compared with all other numbers of graft bundles combined (8.3%, respectively 3.0%; p = 0.014).

CONCLUSION

This study could not prove an increased risk of developing a symptomatic cyclops lesion for patients with an STG graft compared with an ST graft used for ACLR. However, patients with a double-quadruple ACLR had a higher percentage of cyclops lesions compared with all other numbers of graft bundles. Female sex was associated with an increased risk of developing cyclops lesions.

LEVEL OF EVIDENCE

Level III.

Editorial Commentary: Personalized Anterior Cruciate Ligament Reconstruction and Rehabilitation Mitigate Postoperative Arthrofibrosis: Prevention Is the Best Approach

Arthrofibrosis after anterior cruciate ligament reconstruction can become a major complication requiring surgical intervention. The reported incidence approximates 8% but varies widely (2%-35%) and, as not all patients require surgery, may be underreported. Several risk factors are involved. Female sex, older age, surgery within the first month after injury, and meniscus repair are consistently associated with increased risk. Other factors include graft size and type, concomitant procedures, use of anticoagulants, and genetic factors. By identifying risk factors, we can modify our surgical technique and rehabilitation to meet each patient's needs with fewer complications.

Female Sex, Older Age, Earlier Surgery, Anticoagulant Use, and Meniscal Repair Are Associated With Increased Risk of Manipulation Under Anesthesia or Lysis of Adhesions for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To determine what patient or surgical factors are associated with an increased risk of arthrofibrosis requiring manipulation under anesthesia (MUA) or lysis of adhesions (LOA) after anterior cruciate ligament reconstruction (ACLR).

METHODS

A systematic review was performed in adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Cochrane, Embase, and Medline databases were searched for studies published through February 2023. Inclusion criteria were studies that identified risk factors for MUA and/or LOA after ACLR. Studies investigating arthrofibrosis after multiligamentous knee injuries or ACL repair were excluded.

RESULTS

Eleven studies including a total of 333,876 ACLRs with 4,842 subsequent MUA or LOA (1.45%) were analyzed. Increasing age was associated with an increased risk in 3 studies (P < .001, P < .05, P < .01) but was found to have no association another two. Other factors that were identified by multiple studies as risk factors for MUA/LOA were female sex (4 studies), earlier surgery (5 studies), use of anticoagulants other than aspirin (2 studies), and concomitant meniscal repair (4 studies).

CONCLUSIONS

In total, 1.45% of the patients who underwent ACLR and were included in this systematic review had to undergo a subsequent MUA/LOA to treat arthrofibrosis. Female sex, older age, earlier surgery, use of anticoagulants other than aspirin, and concomitant meniscal repair were associated with increased risk of MUA/LOA. The modifiable risks, including use of anticoagulants and time between injury and surgery, can be considered when making treatment decisions.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Quadriceps Tendon With Bone Autograft Has Better Stability and Magnetic Resonance Imaging Maturation Than Hamstring Tendon Autograft After Anterior Cruciate Ligament Reconstruction in Patients With Knee Hyperextension

PURPOSE

To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction between methods using quadriceps tendon with bone (QTB) and hamstring tendon (HT) in patients with hyperextension of the knee.

METHODS

The medical records of patients with knee hyperextension greater than 8° who underwent arthroscopic ACL reconstruction between October 2010 and October 2020 with follow-up for at least 2 years (median, 3 years; interquartile range [IQR], 2.0-4.6 years) were retrospectively reviewed. Side-to-side difference in anterior translation, pivot-shift test grade, Lysholm score, and graft intensity using the Howell grade on magnetic resonance imaging at final follow-up were compared between the QTB and HT groups.

RESULTS

The HT and QTB groups consisted of 42 patients and 21 patients, respectively. The overall mean age was 21.5 years (range, 14-48 years), and the median Tegner Activity Scale score was 6 (range, 3-9). Postoperatively, the median side-to-side difference in anterior translation was 1.75 mm (IQR, 1-3 mm) in the HT group and 1.0 mm (IQR, 0-1.75 mm) in the QTB group (P = .01). Pivot-shift testing showed grade 0 in 74.7%, grade 1 in 18.7%, and grade 2 in 6.6% of patients in the HT group and grade 0 in 85.7% and grade 1 in 14.3% of those in the QTB group (P = .03). The median postoperative Lysholm score was 99 in both groups. Graft signal intensity showed a significant between-group difference: grade I in 52%, grade II in 36%, and grade III in 12% of patients in the HT group versus grade I in 85.7%, grade II in 9.5%, and grade III in 4.8% of those in the QTB group (P = .03).

CONCLUSIONS

In patients who underwent ACL reconstruction for hyperextension of the knee, QTB yielded better clinical outcomes than HT with respect to anterior stability, rotational stability, and graft signal intensity on median 2-year follow-up magnetic resonance imaging.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Hamstring Anterior Cruciate Ligament Autograft Contributes to a Delayed Symptomatic Cyclops Lesion: A Case Report

Cyclops lesions are characterized as fibroid nodules with granulation tissue that looks similar to a cyclops eye during arthroscopy. These are rare postoperative complications following anterior cruciate ligament reconstruction (ACLR), presenting typically within six months of their reconstruction. This case report presents a 21-year-old male, three years following hamstring autograft ACLR, with a symptomatic cyclops lesion. Contrary to the reported literature, this delayed presentation showed a painful flexion contracture of the knee and intraoperative findings consistent with a cyclops lesion. The treatment consisted of surgical debridement and notchplasty with subsequent posterior medial and lateral meniscal horn repairs. This case report presents a lesson to indicate that cyclops lesions can occur in a delayed setting following ACLR and to show a technique for successful surgical management of the lesion.

Editorial Commentary: Risk Factors of Cyclops Syndrome in Quadriceps Autograft Anterior Cruciate Ligament Reconstruction: More Helpful Data in Weighing Graft Choice

Arthrofibrosis after anterior cruciate ligament (ACL) reconstruction can be a devastating complication with risk factors and causes not well established. Cyclops syndrome is a subtype involving localized scar anterior to the graft, which is typically treated with arthroscopic debridement. ACL quadriceps autograft is a newly popular graft option for which clinical data continue to develop. However, recent research shows possible increased risk of arthrofibrosis with quadriceps autograft. Possible causes include inability to achieve active terminal knee extension after extensor mechanism graft harvesting; patient characteristics, including female sex, and social, psychological, musculoskeletal, and hormonal differences; larger graft diameter; concomitant meniscus repair; exposed collagen fibers of the graft abrading the fat pad or tibial tunnel or intercondylar notch; smaller notch size; intra-articular cytokine; and biomechanical stiffness of the graft.

Graft-Specific Surgical and Rehabilitation Considerations for Anterior Cruciate Ligament Reconstruction with the Quadriceps Tendon Autograft

Anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone (BPTB) or hamstring tendon (HT) autograft has traditionally been the preferred surgical treatment for patients returning to Level 1 sports. More recently, international utilization of the quadriceps tendon (QT) autograft for primary and revision ACLR has increased in popularity. Recent literature suggests that ACLR with the QT may yield less donor site morbidity than the BPTB and better patient-reported outcomes than the HT. Additionally, anatomic and biomechanical studies have highlighted the robust properties of the QT itself, with superior levels of collagen density, length, size, and load-to-failure strength compared to the BPTB. Although previous literature has described rehabilitation considerations for the BPTB and HT autografts, there is less published with respect to the QT. Given the known impact of the various ACLR surgical techniques on postoperative rehabilitation, the purpose of this clinical commentary is to present the procedure-specific surgical and rehabilitation considerations for ACLR with the QT, as well as further highlight the need for procedure-specific rehabilitation strategies after ACLR by comparing the QT to the BPTB and HT autografts.

Level of Evidence

Level 5.