Incidence and Risk Factors of Subsequent Meniscal Surgery After Successful Anterior Cruciate Ligament Reconstruction: A Retrospective Study With a Minimum 2-Year Follow-up

Nonanatomic femoral tunnel placement increases the risk of subsequent meniscal surgery after ACLR: Part II-Patients without recurrent ACL injury

PURPOSE

The purpose of this study was to identify risk factors for subsequent meniscal surgery following anterior cruciate ligament (ACL) reconstruction (ACLR) in patients without recurrent ACL injury.

METHODS

Patients aged ≥14 years who underwent primary ACLR with minimum 1-year follow-up and without recurrent ACL injury were retrospectively reviewed. Patient demographics and surgical data at the time of ACLR were collected. Postoperative radiographs were used to measure femoral and tibial tunnel position, and posterior tibial slope. Univariate and multivariate analyses were performed to identify risk factors for subsequent meniscal surgery.

RESULTS

Of 629 ACLRs that fulfilled the inclusion criteria, subsequent meniscal surgery was performed in 65 [10.3%] patients. Multivariate analysis revealed that medial meniscal repair at the time of ACLR, younger age, anterior femoral tunnel position and distal femoral tunnel position were significantly associated with subsequent meniscal surgery (p < 0.001, p = 0.016, p = 0.015, p = 0.035, respectively). The frequency of femoral tunnel placement >10% outside of the literature-established anatomic position was significantly higher in those who underwent subsequent meniscal surgery compared to those who did not (38.3% vs. 20.3%, p = 0.006). Posterior tibial slope and ACL graft type were not significantly associated with subsequent meniscal surgery.

CONCLUSION

Medial meniscal repair at the time of ACLR, younger age and nonanatomic femoral tunnel placement were risk factors for subsequent meniscal surgery in patients without recurrent ACL injury. Femoral tunnel placement <10% outside of the native anatomic position is important to reduce the risk of subsequent meniscal surgery.

LEVEL OF EVIDENCE

Level IV.

A new neural network model that detects graft ruptures and contralateral anterior cruciate ligament injuries

PURPOSE

The purpose of this study was to develop a neural network model for predicting second anterior cruciate ligament (ACL) injury risk following ACL reconstruction using patient features from medical records.

METHODS

Of 486 consecutive patients who underwent primary unilateral ACL reconstruction, 386 patients (198 women, 188 men) with a mean age of 25.1 ± 11.6 years were included in this study. Fifty-eight features, including demographic data, surgical, preoperative and postoperative data, were retrospectively collected from medical records, and features with an incidence of less than 5% were excluded. Finally, 14 features were used for the analysis. The multilayer perceptron was composed of four hidden layers with a rectified linear unit as activation and was trained to maximise the area under the receiver-operating characteristic curve (auROC). Subsequently, validation was carried out through a rigorous threefold cross-validation process. To ascertain the most efficacious combination of features with the highest auROC, a single feature with the least impact on auROC maximisation was systematically eliminated from the comprehensive variable set, ultimately resulting in the retention of a mere two variables.

RESULTS

The median follow-up period was 50.5 (24-142) months. Fifty-seven knees had a second ACL injury, with a graft rupture rate of 7.7% and a contralateral injury rate of 6.9%. The maximum auROC for predicting graft rupture was 0.81 with two features: young age and hamstring graft. Meanwhile, the maximum auROC for predicting contralateral ACL injury was 0.74 with seven features, including young age, presence of medial meniscus tear, small body mass index, hamstring graft, female sex and medial meniscus repair or treatment.

CONCLUSION

A neural network model with patient features from medical records detected graft ruptures and contralateral ACL injuries with acceptable accuracy. This model can serve as a new, useful tool in clinical practice to inform decisions about ACL reconstruction and retuning to sports postoperatively.

LEVEL OF EVIDENCE

Level IV.

Association Between MRI Signal Intensity of the Repaired Lateral Meniscus and Residual Anterolateral Knee Laxity After ACL Reconstruction

Background

Anterolateral knee laxity (ALLx) has been linked to tears of the lateral meniscus (LM) and anterior cruciate ligament (ACL) injury.

Purpose

To investigate the longitudinal relationship between the signal intensity (SI) of the repaired LM on magnetic resonance imaging (MRI) and residual ALLx after ACL reconstruction (ACLR).

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 87 patients who underwent double-bundle ACLR and lateral meniscal repair (mean age, 23.5 years; body mass index, 23.7 kg/m2; 56 women) at a single institution between 2010 and 2019. Proton density-weighted (PDW) and T2-weighted (T2W) MRI was performed at 3, 6, and 12 months postoperatively, and the SI ratio (SIR) was calculated as (SI of the repaired LM)/(SI of the posterior cruciate ligament). At the 12-month follow-up, ALLx was evaluated using the pivot-shift test; an International Knee Documentation Committee grade ≥1 indicated residual ALLx.

Results

Overall, 12 patients (13.8%) exhibited ALLx at 12 months postoperatively. At 3 months postoperatively, the SIR on PDW images (SIR-PDW) was significantly higher in patients with ALLx versus those without ALLx (1.98 ± 0.77 vs 1.49 ± 0.52, respectively; P = .007); there was no difference in the SIR on T2W images between the groups. SIR-PDW at 3 months postoperatively was correlated negatively with patient age (r = -0.308, P = .004). When patients were stratified into a younger (≤22 years; n = 53; ALLx = 7 [13.2%]) and an older (>22 years; n = 34; ALLx = 5 [14.7%]) group, the area under the receiver operating characteristic curves (AUCs) for SIR-PDW in the younger group were statistically significant for predicting the prevalence of ALLx at all follow-up times (AUCs, 0.733-0.788) with optimal cutoff values of 2.00 at 3 months, 1.50 at 6 months, and 1.50 at 12 months. Logistic regression analysis revealed that if younger patients consistently had higher SIR-PDW values than the cutoff values, they were more likely to have residual ALLx (odds ratios, 10.24-23.57).

Conclusion

For younger patients who underwent both ACLR and lateral meniscal repair, higher MRI SI of the repaired LM was associated with a higher prevalence of residual ALLx.

Anterior Cruciate Ligament Reconstruction Using Allograft in Adults Older Than the Age of 40 Years Shows Similar Patient-Reported Outcomes Between Male and Female Patients

Purpose

To evaluate patient-reported outcomes in patients undergoing anterior cruciate ligament (ACL) reconstruction using allograft in patients 40 years of age or older divided by sex.

Methods

Patients age 40 years of age or older who underwent ACL reconstruction by the same surgeon using allograft via anteromedial portal technique were retrospectively identified. Patient-reported outcomes (International Knee Documentation Committee [IKDC], Knee Injury and Osteoarthritis Outcome Score, Tegner, Lysholm, Marx, and Single Assessment Numeric Evaluation) were evaluated and recorded, and outcomes were analyzed by sex.

Results

In total, 159 patients undergoing primary ACL reconstruction were reviewed. Two-year outcomes were obtained. All patients noted improvement in patient-reported outcome measures. Male patients had overall greater postoperative patient-reported outcomes measures at all time points for IKDC, Tegner, Lysholm, Marx, and Single Assessment Numeric Evaluation scores; however, the only significant time points were IKDC 6 months (P = .016), 1 year (P = .012) and Marx 1 year (P = .007) and 2 year (P = .016). Knee Injury and Osteoarthritis Outcome Score scores similarly showed greater postoperative scores at all time points and statistical significance at 3 months (P = .002), 6 months (P = .033), and 1 year (P = .031).

Conclusions

ACL reconstruction in individuals older than the age of 40 years using allograft results in good outcomes compared with preoperative status. Patient-reported outcomes were similar between male and female patients regarding most patient-reported outcome measures.

Level of Evidence

Level III, retrospective cohort study.

Delayed Meniscus Repair Lowers the Functional Outcome of Primary ACL Reconstruction

BACKGROUND

Our purpose was to evaluate whether the time of intervention and the type of meniscus surgery (repair vs. partial meniscectomy) play a role in managing anterior cruciate ligament (ACL) reconstructions with concurrent meniscus pathologies.

METHODS

We performed a prospective cohort study which differentiated between early and late ACL reconstructions with a cut-off at 3 months. Patients were re-evaluated after 2 years.

RESULTS

Thirty-nine patients received an operation between 2-12 weeks after the injury, and thirty patients received the surgery between 13-28 weeks after trauma. The strongest negative predictive factor of the International Knee Documentation Committee subjective knee form in a hierarchical regression model was older age (ß = -0.49 per year; 95% CI [-0.91; -0.07]; p = 0.022; partial R2 = 0.08)). The strongest positive predictive factor was a higher preoperative Tegner score (ß = 3.6; 95% CI [0.13; 7.1]; p = 0.042; partial R2 = 0.07) and an interaction between meniscus repair surgery and the time of intervention (ß = 27; 95% CI [1.6; 52]; p = 0.037; partial R2 = 0.07), revealing a clinical meaningful difference as to whether meniscus repairs were performed within 12 weeks after trauma or were delayed. There was no difference whether partial meniscectomy was performed early or delayed.

CONCLUSIONS

Surgical timing plays a crucial role when surgeons opt for a meniscus repair rather than for a meniscectomy.

Various Definitions of Failure Are Used in Studies of Patients Who Underwent Anterior Cruciate Ligament Reconstruction

Purpose

To conduct a literature review to assess the definitions of anterior cruciate ligament reconstruction (ACLR) failure used throughout the orthopaedic literature.

Methods

A systematic search of Embase, Ovid Medline, SPORTDiscus, and Web of Science was conducted by a university librarian to identity level I-IV clinical studies on ACLR failure. Inclusion criteria consisted of patients who underwent ACLR and included a definition of failure of ACLR. Patients who underwent anterior cruciate ligament (ACL) repairs, animal/cadaver studies, review studies, non-English language articles, and non-full text articles were excluded. Failure data were extracted from each study and categorized. Other data that were extracted included follow-up time after ACLR, failure reoperation rate, and failure reoperation procedure. Descriptive statistics was used to analyze the data.

Results

Out of 2,775 studies, 104 (3.75%) met inclusion criteria and were analyzed in this review. The most common definition of ACLR failure included the use of a physical examination, specifically Lachman's test (21/104 [20.2%]), anterior laxity assessment, or a Pivot-Shift test (24/104 [35.2%]) or undergoing or requiring revision ACLR (39/104 [37.5%]). Although some studies used quantitative tests or imaging to help define "failure," others simply defined it as graft rerupture that was otherwise not defined (22/104 [22.5%]). Other common definitions included: the use of imaging (magnetic resonance imaging/radiographs) to confirm graft re-rupture (37/104 [35.6%]), patient-reported outcomes (recurrent instability)/patient reported outcomes measures (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Tegner) (18/104 [17.3%]), and the use of an arthrometer (KT-1000/2000, Rollimeter, or Kneelax) (17/104 [16.3%]). The least common definitions included graft failure or rerupture confirmed by arthroscopy (13/104 [12.5%]) and nonrevision surgery (2/104 [1.0%]). The failure rate of this procedure ranged from 0% to 100% depending on the definition of "failure."

Conclusion

In this study, we found that a variety of definitions of failure are used among studies published in the orthopaedic literature. The most common criteria for failure of ACLR were the results of physical examination tests (35%), the need for undergoing a revision ACLR (36%), and the use of imaging to diagnose the failure (34%). About 17% of studies included in this review used patient-reported outcomes, specifically recurrent instability, or PROMs (IKDC, KOOS, Tegner) in their assessment of failure of ACLR. The least used definitions of "failure" of ACLR included nonrevision ACLR surgery (2%). Although some studies used similar tests or categories in their definition of failure, there were a variety of score and grade cutoff points between them.

Level of Evidence

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

Incidence of anterior cruciate ligament injury patterns in Japanese judo players from a nationwide insurance database

Objective

This study aimed to characterize the age- and sex-specific Anterior cruciate ligament (ACL) injury rates and related injury patterns in judo players in Japan using the nationwide insurance database.

Methods

This was a descriptive epidemiological study. We examined a total of 2142 adolescents with anterior cruciate ligament injuries registered in the insurance system of the Japan Sports Council between January 2009 and December 2018. The age- and sex-specific incidences were estimated for the levels of 7th, 8th, and 9th grades of junior high school and 10th, 11th, and 12th grades of high school. The anterior cruciate ligament injury circumstances were classified into three patterns based on the impact to the involved knee: high-impact valgus force, low-impact trunk displacement, or no-impact knee twisting.

Results

The incidence of anterior cruciate ligament injury from the 7th to 12th grades were 0.5, 0.9, 0.9, 6.9, 8.6, and 6.1 per 1000 athlete-years in male players and 1.3, 3.8, 3.4, 16.8, 19.5, and 13.6 per 1000 athlete-years in female players. The most prevalent injury pattern was a low-impact contact injury (42.6%) with Osoto-gari, followed by a high-impact contact injury (29.8%). The concomitant medial collateral ligament (MCL) injury rate was 18.1%, which was correlated with a high-impact contact injury (p = 0.005) by multiple regression analysis.

Conclusions

The highest incidence of age- and sex-specific anterior cruciate ligament injury was 19.5 per 1000 athlete-years in female high school students in the 11th grade. The most frequent injury pattern was low-impact contact injury with trunk displacement, indicating that trunk stabilization training could help prevent anterior cruciate ligament injury in judo.

Surgeon anterior cruciate ligament reconstruction volume and rates of concomitant meniscus repair

PURPOSE

The purpose of this study was to assess the effect of surgeon anterior cruciate ligament reconstruction (ACLR) volume on rates of ACLR with concomitant meniscus repair versus meniscectomy and subsequent meniscus surgeries.

METHODS

A retrospective review was conducted from a database of all ACLR performed between 2015 and 2020 at a large integrated health care system. Surgeon volume was categorized as < 35 ACLR per year (low-volume), and ≥ 35 ACLR per year (high-volume). Rates of concomitant meniscus repair and meniscectomy were compared between low-volume and high-volume surgeons. Subgroup analyses compared the rates of subsequent meniscus surgery and procedure time based on surgeon volume and meniscus procedure type.

RESULTS

A total of 3,911 patients undergoing ACLR were included. High-volume surgeons performed concomitant meniscus repair statistically significantly more often than low-volume surgeons (32.0% vs 10.7%, p < 0.001). Binary logistic regression indicated 4.15 times higher odds of meniscus repair among high-volume surgeons. Subsequent meniscus surgery occurred more commonly following ACLR with meniscus repair among low-volume surgeons (6.7% vs 3.4%, p = 0.047), but not high-volume surgeons (7.0% vs 4.3%, p = 0.079). Low-volume surgeons also had longer procedure times for concomitant meniscus repair (129.9 vs 118.3 min, p = 0.003) and meniscectomy (100.6 vs 95.9 min, p = 0.003).

CONCLUSIONS

Data from this study shows that surgeons with lower volume of ACLR select meniscus resection statistically significantly more often than higher-volume surgeons. However, an abundance of literature is available to show that meniscus loss negatively affects the development of post-traumatic osteoarthritis in patients Therefore, as demonstrated in this study by high-volume surgeons, the meniscus should be repaired and protected whenever possible.

LEVEL OF EVIDENCE

III.

Meniscal resection increases the risk of residual knee laxity even in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction with eight strands of hamstring autografts

PURPOSE

To compare the midterm clinical outcomes of different meniscal surgeries in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction (DB-ACLR) with eight strands of hamstring (HT8) autografts and explore the potential predictive risk factors for residual knee laxity.

METHODS

From 2010 to 2017, a total of 410 patients who underwent anatomic trans-tibial DB-ACLR with HT8 autografts (169 patients without meniscal surgery, 105 patients with meniscal repair, and 136 patients with meniscal resection) were included in this study. The equivalent graft diameter was introduced to make the total graft size of DB-ACLR comparable with that of single-bundle ACLR and calculated as the square root of the quadratic sum of the diameter for each bundle. Residual laxity was defined as excessive anterior tibial translation or residual pivot shift at any follow-up visit, while graft rupture was confirmed by second-look arthroscopy or magnetic resonance imaging.

RESULTS

The mean follow-up period was 8.3 ± 2.2 years. The mean equivalent graft diameter was 9.9 ± 0.7 mm. Graft rupture was confirmed in 16 (3.9%) patients, while residual laxity was detected in 72 (17.6%) patients (34 [25.0%] in the meniscal resection group vs. 22 [13.0%] in the no meniscal surgery group, p = 0.021). In the multivariate logistic regression analysis, high-grade preoperative knee laxity (odds ratio OR 2.04, p = 0.020), equivalent graft diameter < 9 mm (OR 3.31 compared with 9-10 mm, p = 0.012; OR 3.28 compared with ≥ 10 mm, p = 0.019), and meniscal resection (OR 1.94 compared with no meniscal surgery, p = 0.045) were associated with residual laxity.

CONCLUSION

During a midterm follow-up, meniscal resection increased the risk of residual knee laxity even in patients undergoing anatomic DB-ACLR with HT8 autografts. Increasing the hamstring graft diameter and preserving the menisci are important strategies for ACLR to restore knee stability.

LEVEL OF EVIDENCE

Level III.

Early ACLR and Risk and Timing of Secondary Meniscal Injury Compared With Delayed ACLR or Nonoperative Treatment: A Time-to-Event Analysis Using Machine Learning

BACKGROUND

Surgical and nonoperative management of anterior cruciate ligament (ACL) injuries seek to mitigate the risk of knee instability and secondary meniscal injury. However, the associated risk and timing of secondary meniscal tears have not been completely elucidated.

PURPOSE

To compare risk and timing of secondary meniscal injury between patients receiving nonoperative management, delayed ACL reconstruction (ACLR), and early ACLR using a machine learning survival analysis.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A geographic database was used to identify and review records of patients with a diagnosis of ACL rupture between 1990 and 2016 with minimum 2-year follow-up. Patients undergoing ACLR were matched 1:1 with nonoperatively treated controls. Rate and time to secondary meniscal tear were compared using random survival forest algorithms; independent models were developed and internally validated for predicting injury-free duration in both cohorts. Performance was measured using out-of-bag c-statistic, calibration, and Brier score. Model interpretability was enhanced using global variable importance and partial dependence curves.

RESULTS

The study included 1369 patients who underwent ACLR and 294 patients who had nonoperative treatment. After matching, no significant differences in rates of secondary meniscal tear were found (P = .09); subgroup analysis revealed the shortest periods of meniscal survival in patients undergoing delayed ACLR. The random survival forest algorithm achieved excellent predictive performance for the ACLR cohort, with an out-of-bag c-statistic of 0.80 and a Brier score of 0.11. Significant variables for risk of meniscal tear for the ACLR cohort included time to return to sports or activity ≤350 days, time to surgery ≥50 days, age at injury ≤40 years, and high-impact or rotational landing sports, whereas those in the nonoperative cohort model included time to RTS ≤200 days, visual analog scale pain score >3 at consultation, hypermobility, and noncontact sports.

CONCLUSION

Delayed ACLR demonstrated the greatest long-term risk of meniscal injury compared with nonoperative treatment or early ACLR. Risk factors for decreased meniscal survival after ACLR included increased time to surgery, shorter time to return to sports or activity, older age at injury, and involvement in high-impact or rotational landing sports. Pending careful external validation, these models may be deployed in the clinical space to provide real-time insights and enhance decision making.

Effect of a new remnant-preserving technique with anatomical double-bundle anterior cruciate ligament reconstruction on MRI-based graft maturity: a comparison cohort study

PURPOSE

To investigate the effects of a new remnant-preserving double-bundle anterior cruciate ligament reconstruction (ACLR) technique, focused on avoiding remnant damage and preserving continuity of remnants, on graft maturity using magnetic resonance imaging (MRI).

METHODS

A total of 169 patients were divided into three groups: 41 in the preservation group, 70 in the resection group, and 58 in the absent group. In the preservation group, rather than passing the graft through the remnant tissue, the graft was reconstructed such that the anteromedial and posterolateral bundles sandwiched the remnant to avoid damage to the remnant and maintain its continuity. Based on 1-year postoperative MRI, the grafts were divided into three regions: distal, middle, and proximal. The signal/noise quotient (SNQ) of each region of interest was calculated to evaluate the signal intensity of the graft and was compared among the three groups. Additionally, to identify factors influencing graft maturity, a multiple regression analysis was performed with SNQ as the dependent variable and patient demographics, bone morphology, and surgical factors as independent variables.

RESULTS

In a three-group comparison of mean SNQs, the distal region was 3.3 ± 3.4, 8.9 ± 8.3, and 9.0 ± 8.6 (p < 0.001), the middle region was 5.3 ± 3.7, 10.9 ± 11.1, and 11.3 ± 10.2 (p < 0.001), and the proximal region was 6.8 ± 4.5, 11.1 ± 8.8, and 11.7 ± 10.8 (p = 0.017), in order of the preservation, resection, and absent groups, respectively. That indicated that the remnant-preserving ACLR was more hypointense than ACLR with remnant resection or absent in all three regions. Multiple regression analysis showed that remnant preservation remained the relevant factor affecting SNQ of the graft at the distal and middle levels.

CONCLUSION

The new remnant-preserving anatomic double-bundle ACLR had significantly better graft maturity, measured by SNQ on MRI, than the remnant resection and absent groups. The remnant procedure was the relevant factor affecting graft maturity.

LEVEL OF EVIDENCE

Level III.

Risk Factors Associated with Cartilage Defects after Anterior Cruciate Ligament Rupture in Military Draftees

This study aimed to evaluate the different clinical results and factors associated with cartilage defects in military draftees who underwent different treatments after anterior cruciate ligament (ACL) rupture. Overall, 105 patients who had sustained ACL rupture were military draftees who underwent a conscription examination for physical status assessment from January 2012 to December 2020. Patients were divided into three groups: conservative treatment after ACL rupture, status post-anterior cruciate ligament reconstruction (ACLR), but graft rupture, and status post-ACLR with graft intact. Inter-group comparisons and statistical analyses were performed for age, body mass index (BMI), thigh circumference difference, side-to-side difference in anterior knee translation by KT-2000, meniscus tear, and cartilage defect. Multivariate logistic regression analysis was used to determine the factors associated with cartilage defects. The multivariable regression model showed that BMI (odds ratio OR: 1.303; 95% CI: 1.016–1.672; p = 0.037), thigh circumference difference (OR: 1.403; 95% CI: 1.003–1.084; p = 0.034), tear of lateral meniscus (LM) and medial meniscus (MM) (OR: 13.773; 95% CI: 1.354–140.09; p = 0.027), and graft rupture group (OR: 5.191; 95% CI: 1.388–19.419; p = 0.014) increased the risk of cartilage defects. There was no correlation between cartilage defects and age, KT-2000 difference, tear of LM or MM, or graft intact group. Progression of osteoarthritis was concerned after ACL rupture, and this study identified several factors of post-ACLR graft rupture, greater thigh circumference difference, BMI, and meniscus tear of both LM and MM affecting cartilage defects, which represent early degenerative osteoarthritis changes of the knee. The results of this study should be customized for rehabilitation and military training, especially in military draftees with ACL injuries.

Failure and Complication Rates in Common Sports and Arthroscopic Procedures: Reality Check

Expectations following sports medicine and arthroscopic procedures have been elevated because of captivating modern-day media coverage of high-profile athletic injuries, surgery, and rapid return to sports. Unfortunately, this general perception may be misleading, and orthopedic sports medicine physicians must be aware of the harsh reality of the trials and tribulations associated with the subspecialty. The purpose of this review article is to provide an updated brief overview of the complications and failure rates associated with common arthroscopic procedures including rotator cuff repair, biceps tenodesis, Bankart procedure, Latarjet procedure, anterior cruciate ligament reconstruction, anterior cruciate ligament repair, meniscal repair, tibial tubercle osteotomy, and medial patellofemoral ligament reconstruction. Highlighting the complications is the first step toward early recognition, enhancing preventative measures, and successful management.

Early Return to Sports to Continue the Season after Anterior Cruciate Ligament Injury Is Not Recommended for Student Athletes

Objective:

The objectives of this study were to investigate whether student athletes with anterior cruciate ligament (ACL) injuries who returned to sports (RTS) without reconstruction could continue their sporting activities until the end of the season and whether there was an increase in secondary damage associated with knee instability.

Methods:

Altogether, 288 skeletally mature patients aged <25 years with new-onset isolated primary ACL injuries were included. Of these, 20 student athletes continued playing sports without ACL reconstruction to try to finish the season and were classified as the early return to sports (ERS) group; the remaining 268 patients, who immediately quit sports and underwent surgery, were classified as the non-ERS group. Knee symptoms and sporting performance for the rest of the season were assessed for the ERS group. The presence of secondary damage, e.g., meniscus injuries and chondral lesions, associated with instability were compared between the two groups.

Results:

Fourteen ERS-group athletes (70%) indicated that their knees had given way during sporting activities, and seven athletes (35%) were unable to complete the season. In the ERS group, the mean self-estimated performance level after injury was 3.8 ± 2.5 (numeric rating scale 0–10). Despite the RTS period being relatively short, medial meniscus tears (P <0.001) significantly increased in the ERS group, and three patients experienced locking of the medial meniscus and required immediate surgery.

Conclusions:

Although ERS without reconstruction to complete the season may be a reasonable strategy for ACL injury, patients’ self-estimated performance level was low and meniscal and cartilage injury rates significantly increased.