Location of medial collateral ligament tears: introduction to a magnetic resonance imaging-based classification.

PURPOSE: Despite established tear grade classifications, there is currently no radiological classification for sMCL tear locations. This study aims to establish a magnetic resonance imaging (MRI) tear location classification system for sMCL tears, to enhance understanding and guide treatment decisions by categorizing tear types. METHODS: A retrospective search in a single institution's MRI database identified patients with acute, Grade III sMCL tears (< 30 days between injury and MRI) from January to December 2022. Non-acute and partial tears were excluded, and three observers assessed tear types based on the proposed sMCL MRI tear location system: type I (proximal 25%), Ib (proximal femoral bony avulsion), II (midsubstance, 25-75%), III (distal 25%), IIIb (distal tibial bony avulsion), IIIs (Stener-like lesion). The interclass correlation coefficient (ICC) was used to assess interrater and intrarater reliability for continuous data; Fleiss and Cohen's kappa assessed interrater and intrarater reliability for categorical data. RESULTS: MRI scans of thirty patients with diagnosed sMCL injuries (53% female, mean age 37 ± 13 years, range 16-68 years) were included based on inclusion/exclusion criteria. Interrater reliability was excellent (ICC: 0.968, 95% CI, 0.933-0.985), and intrarater reliability was excellent (ICC: 0.938, 95% CI: 0.874-0.970 & 0.900, 95% CI, 0.789-0.952). Type I injuries were most common (60%), followed by type III (33.3%), type II (3.3%), type Ib (3.3%), type IIIb (0.0%), and type IIIs (0.0%). CONCLUSION: The presented MRI-based sMCL tear location classification provides a reproducible system for grading high-grade sMCL injuries. We propose that this framework will significantly unify tear location understanding and support more informed treatment decisions.

Arthroscopic Anatomic Anterior Cruciate Ligament Primary Repair Restores Anterior Tibial Translation Intraoperatively at Time Zero With No Additional Effect of Suture Augmentation.

PURPOSE: To intraoperatively evaluate the ability of anterior cruciate ligament (ACL) primary repair (ACLPR) to restore anterior tibial translation (ATT) at time zero and to assess the influence of additional suture augmentation (SA) on ATT. METHODS: Patients with proximal ACL tears undergoing arthroscopic ACLPR with dual-suture anchor fixation were included in this time-zero clinical study. Laxity measurements were taken with a digital arthrometer to evaluate ATT stability preoperatively in the office (T0) as a standardized diagnostic tool, preoperatively under anesthesia (T1), at time zero intraoperatively after ACLPR but prior to SA fixation (T2), and after SA fixation (T3). RESULTS: A total of 27 patients (mean age ± standard deviation [SD], 35.1 ± 12.0 years) with proximal ACL tears and significant preoperative (T0) ATT side-to-side differences (SSDs) (mean ± SD, 4.1 ± 1.5 mm) were evaluated. ACLPR was shown to restore ATT SSD at time zero (mean ± SD, 0.2 ± 1.1 mm) given that a significant reduction in ATT SSD (mean difference ± standard error, -4.7 ± 0.21 mm; P < .001) was achieved when comparing preoperative and intraoperative measurements after separate refixation of both ACL bundles with suture anchors. Additional SA fixation did not further decrease ATT when comparing measurements of the ipsilateral leg after ACL refixation and after SA fixation (mean difference ± SD, 0.03 ± 0.22 mm; P = .496). CONCLUSIONS: ACLPR with dual-suture anchor fixation restores time-zero ATT laxity in adults with proximal ACL tears. Additional SA fixation in full knee extension does not further decrease ATT. CLINICAL RELEVANCE: This study provides important information about the effectiveness of ACLPR in restoring ATT. SA with the knee fixed in full knee extension does not further decrease ATT; therefore, augmentation may not lead to overconstraint of the knee or stress shielding of the repaired ACL.

Anterior cruciate ligament primary repair revision rates are increased in skeletally mature patients under the age of 21 compared to reconstruction, while adults (>21 years) show no significant difference: A systematic review and meta-analysis.

PURPOSE: To evaluate the impact of age as a risk factor on the revision rates of anterior cruciate ligament (ACL) primary repair (ACLPR), dynamic intraligamentary stabilization (DIS) and bridge-enhanced ACL restoration (BEAR) compared to ACL reconstruction (ACLR). METHODS: A systematic literature search was performed for comparative studies comparing outcomes for ACLPR, DIS or BEAR to ACLR. A random-effects meta-analysis was performed to assess nondifferentiated and age-differentiated (skeletally mature patients ≤21 and >21 years) ACL revision and reoperation risk, as well as results for subjective outcomes. Methodological study quality was assessed using the Risk of Bias Tool 2.0c and Methodological Index for Nonrandomized Studies tools. RESULTS: A total of 12 studies (n = 1277) were included. ACLR demonstrated a lower nonage-stratified revision risk at 2 years versus ACLPR, DIS and BEAR, but a similar revision risk at 5 years when compared to DIS. However, an age-stratified analysis demonstrated a significantly increased ACLPR revision risk as compared to ACLR in skeletally mature patients ≤21 years of age (risk ratios [RR], 6.33; 95% confidence interval [CI], 1.18-33.87, p = 0.03), while adults (>21 years) showed no significant difference between groups (RR, 1.48; 95% CI, 0.25-8.91, n.s.). Furthermore, DIS reoperation rates were significantly higher than respective ACLR rates (RR, 2.22; 95% CI, 1.35-3.65, p = 0.002), whereas BEAR (RR, 1.07; 95% CI, 0.41-2.75, n.s.) and ACLPR (RR, 0.81; 95% CI, 0.21-3.09, n.s.) showed no differences. IKDC scores were equivalent for all techniques. However, ACLPR exhibited significantly better FJS (mean difference, 11.93; 95% CI, 6.36-17.51, p < 0.0001) and Knee injury and Osteoarthritis Outcome Score Symptoms (mean difference, 3.01; 95% CI, 0.42-5.60, p = 0.02), along with a lower Tegner activity reduction. CONCLUSIONS: ACLPR in skeletally mature patients ≤21 years of age is associated with up to a six-fold risk increase for ACL revision surgery compared to ACLR; however, adults (>21 years) present no significant difference. Based on the current data, age emerges as a crucial risk factor and should be considered when deciding on the appropriate treatment option in proximal ACL tears. LEVEL OF EVIDENCE: Level III.

Treating Combined Anterior Cruciate Ligament and Medial Collateral Ligament Injuries Operatively in the Acute Setting Is Potentially Advantageous.

Combined injury of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) remains among the most common knee injury patterns in orthopaedics. Optimal treatment of grade III MCL injuries is still debated, especially when combined with ACL injury. Most patients with these severe injuries are treated conservatively for at least 6 weeks to allow for MCL healing, followed by delayed ACL reconstruction. Although acute treatment of the MCL was common in the 1970s, postoperative stiffness was frequently reported. Moreover, studies of such treatment failed to show clinical benefits of surgical over conservative treatment, and the MCL exhibited intrinsic healing capacity, leading to the consensus that all MCL injuries are treated conservatively. The current delayed treatment algorithm for ACL-MCL injuries has several disadvantages. First, MCL healing may be incomplete, resulting in residual valgus laxity that places the ACL graft at greater risk of failure. Second, delayed treatment lengthens the overall rehabilitation period, thereby prolonging the presence of atrophy and delaying return to preinjury activity levels. Third, the initial healing period leaves the knee unstable for longer and risks further intra-articular damage. Acute simultaneous surgical treatment of both ligaments has the potential to avoid these shortcomings. This article will review the evolution of treatment of ACL-MCL injuries and explain how it shifted toward the current treatment algorithm. We will (1) discuss why the consensus shifted, (2) discuss the shortcomings of the current treatment plan, (3) discuss the potential advantages of acute simultaneous treatment, and (4) present an overview of the available literature.

Role of Age on Success of Arthroscopic Primary Repair of Proximal Anterior Cruciate Ligament Tears.

PURPOSE: To assess failure rates and patient-reported outcomes measures following arthroscopic primary anterior cruciate ligament (ACL) repair of proximal tears in different age groups. METHODS: Between 2008 and 2017, the first 113 consecutive patients treated with repair were retrospectively reviewed at minimum of 2 years. Patients were stratified into 3 age groups: ≤21, 22-35, and >35 years. Primary outcomes were ipsilateral reinjury or reoperation, and contralateral injury rates, and secondary outcomes consisted of Lysholm, modified Cincinnati, Single Assessment Numeric Evaluation, International Knee Documentation Committee subjective, pain, and satisfaction scores. Group differences were compared using χ2 tests and Mann-Whitney U tests. RESULTS: Follow-up was obtained in 113 patients (100%). Median age was 35 years (interquartile range [IQR] 23-43) and median follow-up was 2.2 years (IQR 2.0-2.8). Overall, ACL reinjury occurred in 13 patients (11.5%), reoperation in 7 patients (6.2%), complications in 2 patients (1.8%) and contralateral ACL injury in 4 patients (3.5%). Overall, median Lysholm was 95 (IQR 89-100) and International Knee Documentation Committee subjective 92 (IQR 84-99). Treatment failure was significantly greater in the youngest age group (37.0%) as compared with the middle and older groups (4.2% and 3.2%, both P < .005). No significant differences were seen in reoperation, complication, or contralateral injury rates between groups (all P > .2), nor in patient-reported outcomes measures between the groups (all P > .1). CONCLUSIONS: The failure rate of primary repair of proximal ACL tears is high in patients aged 21 or younger (37.0%), and this should be taken into account when discussing repair in this patient group. In patients older than 21, repair may be an excellent treatment with low failure (3.5%) and complication rates (1.2%) and good subjective scores. LEVEL OF EVIDENCE: Level III, retrospective comparative therapeutic trial.

Distal remnant length can be measured reliably and predicts primary repair of proximal anterior cruciate ligament tears.

PURPOSE: To assess the reliability and predictive value of quantifying anterior cruciate ligament (ACL) tear location on magnetic resonance imaging (MRI) and assess the predictive value of tear location on the eligibility for arthroscopic primary repair of proximal ACL tears. METHODS: In this case-control study, all adult patients undergoing acute ACL surgery between 2008 and 2020 were retrospectively reviewed. All patients were treated with the treatment algorithm of undergoing primary repair when proximal tears with sufficient tissue quality were present intraoperatively, and otherwise underwent single-bundle ACL reconstruction. Sagittal MRI images were reviewed to measure proximal and distal remnant lengths along the anterior aspect of the torn ligament, and tear location was calculated as distal remnant divided by total remnant length. Interobserver and intraobserver reliability for remnant measurements were calculated. Then, receiver operating curve analysis (ROC) was performed to calculate the optimal cut-off for the possibility of primary repair with the different measurements. RESULTS: Two hundred and forty-eight patients were included, of which 151 underwent repair (61%). Inter- and intraobserver reliability ranged between 0.92 and 0.96 [95% confidence interval (CI) 0.55-0.98] and 0.91-0.97 (95% CI 0.78-0.98, respectively). All patients with a tear location of ≥ 80% on MRI could undergo repair, whereas all patients with tear location of < 60% required reconstruction. The positive predictive value of a proximal quarter tear (≥ 75%) on primary repair was 94%. Older age was correlated with more proximal tear location (p < 0.001), but there was no correlation between tear location and gender, BMI, or timing of surgery (all n.s). CONCLUSION: This study showed that tear location could reliably be quantified on MRI by assessing distal and proximal remnant lengths. Tear location in the proximal quarter of the ACL was found to have a positive predictive value for repairability of 94%. These findings may assist orthopaedic surgeons in evaluating which patients are eligible for primary ACL repair preoperatively. LEVEL OF EVIDENCE: III.

Patients Forget About Their Operated Knee More Following Arthroscopic Primary Repair of the Anterior Cruciate Ligament Than Following Reconstruction.

PURPOSE: To assess the extent to which patients forget their operative knee joint on a daily basis following arthroscopic primary repair as compared with reconstruction of the anterior cruciate ligament (ACL) at short- to mid-term follow-up. METHODS: For this retrospective study, all patients undergoing ACL surgery between May 2012 and May 2017 were identified. All patients were treated with the algorithm of undergoing arthroscopic primary repair for proximal tears and reconstruction for nonrepairable tears. Patients were contacted to complete the Forgotten Joint Score-12 questionnaire between 2 and 5 years following surgery. A greater score represents a more favorable outcome indicating the patient's ability to "forget" the joint in everyday life, whereas lower scores indicate a less-favorable outcome. Data were analyzed using independent t-tests and χ2 tests, and multiple linear regression analysis was performed to correct for potential confounders. RESULTS: Eighty-three patients completed the questionnaire (57%). Patients who underwent primary repair thought about their operated knee less when compared with those patients who underwent reconstruction (85.3 ± 14.2 vs 74.3 ± 23.3, P = .022). These differences were significantly greater in patients older than 30 years (85.3 ± 12.9 vs 62.6 ± 24.9, P = .007), male patients (85.0 ± 13.6 vs 72.5 ± 24.7, P = .037), and patients with a body mass index greater than 25 (85.9 ± 14.5 vs 64.7 ± 25.6, P = .009). After we corrected for potential confounders, the overall difference remained significant (P = .045). CONCLUSIONS: Based on the data in this study, patients undergoing arthroscopic primary ACL repair can expect to have less daily awareness of their operated knee at short- to mid-term follow-up as compared with patients undergoing ACL reconstruction. LEVEL OF EVIDENCE: Retrospective comparative study, level III.

Large variation in indications, preferred surgical technique and rehabilitation protocol for primary anterior cruciate ligament repair: a survey among ESSKA members.

PURPOSE: To assess current surgical preferences and practice patterns regarding primary anterior cruciate ligament (ACL) repair among European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) members. METHODS: A web-based survey was designed, including questions regarding indications for primary repair, outcomes of primary repair, and rehabilitation protocols. An invitation for study participation was sent by email to all ESSKA e-mail contacts. Descriptive statistics were performed. RESULTS: A total of 169 surgeons responded to the survey (7% response rate of active members). Lack of supporting scientific evidence is the main reason for not using repair as a surgical treatment (63%). Most important indications were proximal avulsion tears (84%), younger age (49%), and older age (34%). Among those currently utilizing repair as a treatment option, transosseous tunnel fixation repair (34%) and repair with internal brace using transosseous tunnel fixation (32%) were the most preferred techniques. Eleven percent indicated dynamic intraligamentary stabilization as their preferred technique. A similar rate of progression for rehabilitation for repair and reconstruction techniques was noted among respondents. CONCLUSION: This practice survey shows that the majority of surgeons indicated the main reason for not incorporating primary repair in their current practices was a lack of supporting scientific evidence. Among those holding favourable attitudes and beliefs, most surgeons indicated patients with proximal tears, younger-aged, and older-aged patients might be eligible for repair. Prospective studies with higher levels of evidence are warranted to establish guidelines for repair, including indications, optimal surgical technique, and rehabilitation protocols. LEVEL OF EVIDENCE: V (expert opinion).

Trauma and femoral tunnel position are the most common failure modes of anterior cruciate ligament reconstruction: a systematic review.

PURPOSE: To improve outcomes of anterior cruciate ligament reconstruction (ACLR), it is important to understand the reasons for failure of this procedure. This systematic review was performed to identify current failure modes of ACLR. METHODS: A systematic search was performed using PubMed, EMBASE, Cochrane, and annual registries for ACLR failures. Studies were included when failure modes were reported (I) of ≥ 10 patients and (II) at a minimum of two-year follow-up. Modes of failure were also compared between different graft types and in femoral tunnel positions. RESULTS: This review included 24 cohort studies and 4 registry-based studies (1 level I, 1 level II, 10 level III, and 16 level IV studies). Overall, a total of 3657 failures were identified. The most common single failure mode of ACLR was new trauma (38%), followed by technical errors (22%), combined causes (i.e. multiple failure mechanisms; 19%), and biological failures (i.e. failure due to infection or laxity without traumatic or technical considerations; 8%). Technical causes also played a contributing role in 17% of all failures. Femoral tunnel malposition was the most common cause of technical failure (63%). When specifically looking at the bone-patellar tendon-bone (BPTB) or hamstring (HT) autografts, trauma was the most common failure mode in both, whereas biological failure was more pronounced in the HT group (4% vs. 22%, respectively). Technical errors were more common following transtibial as compared to anteromedial portal techniques (49% vs. 26%). CONCLUSION: Trauma is the single leading cause of ACLR failure, followed by technical errors, and combined causes. Technical errors seemed to play a major or contributing role in large part of reported failures, with femoral tunnel malposition being the leading cause of failure. Trauma was also the most common failure mode in both BPTB and HT grafts. Technical errors were a more common failure mode following transtibial than anteromedial portal technique. LEVEL OF EVIDENCE: IV.

Correction to: Arthroscopic primary repair of proximal anterior cruciate ligament tears seems safe but higher level of evidence is needed: a systematic review and meta-analysis of recent literature.

Unfortunately.

Arthroscopic primary repair of proximal anterior cruciate ligament tears seems safe but higher level of evidence is needed: a systematic review and meta-analysis of recent literature.

PURPOSE: To assess the outcomes of the various techniques of primary repair of proximal anterior cruciate ligament (ACL) tears in the recent literature using a systematic review with meta-analysis. METHODS: PRISMA guidelines were followed. All studies reporting outcomes of arthroscopic primary repair of proximal ACL tears using primary repair, repair with static (suture) augmentation and dynamic augmentation between January 2014 and July 2019 in PubMed, Embase and Cochrane were identified and included. Primary outcomes were failure rates and reoperation rates, and secondary outcomes were patient-reported outcome scores. RESULTS: A total of 13 studies and 1,101 patients (mean age 31 years, mean follow-up 2.1 years, 60% male) were included. Nearly all studies were retrospective studies without a control group and only one randomized study was identified. Grade of recommendation for primary repair was weak. There were 9 out of 74 failures following primary repair (10%), 6 out of 69 following repair with static augmentation (7%) and 106 out of 958 following dynamic augmentation (11%). Repair with dynamic augmentation had more reoperations (99; 10%), and more hardware removal (255; 29%) compared to the other procedures. All functional outcome scores were > 85% of maximum scores. CONCLUSIONS: This systematic review with meta-analysis found that the different techniques of primary repair are safe with failure rates of 7-11%, no complications and functional outcome scores of > 85% of maximum scores. There was a high risk of bias and follow-up was short with 2.1 years. Prospective studies comparing the outcomes to ACL reconstruction with sufficient follow-up are needed prior to widespread implementation. LEVEL OF EVIDENCE: IV.

The healing potential of an acutely repaired ACL: a sequential MRI study.

BACKGROUND: Recently, there has been renewed interest in primary anterior cruciate ligament (ACL) repair. The aim of this study is to report early clinical and radiological results of a consecutive series of acute ACL tears treated with arthroscopic primary ACL repair within 14 days from injury. PATIENTS AND METHODS: A consecutive series of patients with acute ACL tears were prospectively included in the study. Based on MRI appearance, ACL tears were classified into five types, and tissue quality was graded as good, fair, and poor. Patients with type I, II, and III tears and at least 50% of ACL tibial remnant intact with good tissue quality were ultimately included. Clinical outcomes were measured using the Tegner Lysholm Knee Scoring Scale (TLKSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), subjective and objective International Knee Documentation Committee (IKDC) scores, and KT-1000. Patients were also followed up with MRI evaluations at 1, 3, and 6 months postoperatively. ACL appearance was graded based on morphology (normal or abnormal) and signal intensity (isointense, intermediate, and hyperintense). RESULTS: The mean TLKSS was 98.1, the mean subjective IKDC was 97.6, and the mean KOOS was 98.2. The objective IKDC score was A in eight of ten patients and B in two patients. KT-1000 measurements showed a maximum manual side-to-side difference of less than 2 mm in eight of ten patients, whereas two patients showed a difference of 3 mm. The morphology of the repaired ACL was normal (grade 1) at 1 month follow-up in ten of ten cases, and this appearance persisted at 3 and 6 months postoperatively. The signal intensity at 1 month postoperatively was graded as isointense (grade 1) in four of ten patients, intermediate (grade 2) in five of ten patients, and hyperintense (grade 3) in one of ten patients. At both 3 and 6 months postoperatively, the signal intensity was graded as isointense (grade 1) in nine of ten patients and intermediate (grade 2) in one of ten patients. CONCLUSIONS: Arthroscopic primary ACL repair performed acutely in a carefully selected group of patients with proximal ACL tears and good tissue quality showed good early clinical and radiological results. LEVEL OF EVIDENCE: Level 4.

Arthroscopic primary repair of proximal anterior cruciate ligament tears: outcomes of the first 56 consecutive patients and the role of additional internal bracing.

PURPOSE: Recent outcomes of arthroscopic primary repair of proximal anterior cruciate ligament (ACL) tears have been promising in small cohort studies. The purpose of this study was to assess outcomes of arthroscopic ACL repair in a larger cohort and to assess the role of additional augmentation. METHODS: The first 56 consecutive patients that underwent arthroscopic ACL repair were examined at minimum 2-year follow-up. The latter 27 patients [48.2% (27/56)] received additional internal bracing with ACL repair. All 56 patients were included (100% follow-up). Mean age at surgery was 33.5 ± 11.3 years (59% male) and mean follow-up 3.2 ± 1.7 years. Clinical examination was performed using the objective International Knee Documentation Committee (IKDC) form. Subjective outcomes were obtained using the Lysholm, modified Cincinnati, Single Assessment Numeric Evaluation (SANE), and subjective IKDC scores. RESULTS: Six repairs (10.7%) failed and four additional patients underwent reoperation (7.1%): two for meniscus tears and two for suture anchor irritation. Objective IKDC scores were A in 38 (73%), B in 8 (15%) and C/D in 6 (12%) patients. Mean Lysholm score was 94 ± 7.6, modified Cincinnati 94 ± 8.9, SANE 90 ± 12.5, pre-injury Tegner 6.7 ± 1.5, current Tegner 6.2 ± 1.5, and subjective IKDC 90 ± 10.9. Failures rates were 7.4% with and 13.8% without internal bracing (P = 0.672). There were no statistically significant or clinically relevant differences in subjective outcomes. CONCLUSION: Arthroscopic primary repair has resulted in good objective and subjective outcomes at 3.2-year follow-up in a carefully selected population. The role of additional internal bracing is possibly beneficial, but larger groups are needed to assess this. LEVEL OF EVIDENCE: III.

The Locations of Anterior Cruciate Ligament Tears in Pediatric and Adolescent Patients: A Magnetic Resonance Study.

BACKGROUND: Recently, a resurgence of interest has been noted in anterior cruciate ligament (ACL) preservation in pediatric and adolescent patients. Different tear types, defined by their tear location, require different preservation techniques: proximal and distal avulsion tears can be treated with arthroscopic primary repair, whereas primary repair with biological scaffold has been proposed for midsubstance tears. The goal of this study was to assess the distribution of different tear types in pediatric and adolescent patients, as these are currently unknown. METHODS: A retrospective search in an institutional radiographic database was performed for patients under 18.0 years undergoing knee magnetic resonance imaging (MRI) for ACL tears between June 2005 and June 2016. Patients with reports of chronic tears, partial tears, and multiligamentous injuries were excluded.Tear locations were graded using MRI as: proximal avulsion (distal remnant length >90% of total length; type I), proximal (75% to 90%; type II), midsubstance (25% to 75%; type III), distal (10% to 25%; type IV), and distal avulsion (<10%; type V). RESULTS: A total of 274 patients (59% girls; mean±SD age, 15.1±2.1 y; range, 6.9 to 18.0 y) were included. Frequency of type I tears was 15%, type II 23%, type III 52%, type IV 1%, and type V 8% (of which 7% had bony avulsion).Prevalence of tear types varied with age. At age 6 to 10 years, 93% were type V (bony) avulsion tears. At age 11 to 13 years, 32% were type I, 16% type II, 32% type III, and 16% type V. At age 14 to 17 years, type III tears were more common (57%) than type I (14%), type II (25%) and type V (2%) tears. CONCLUSIONS: It was noted that the ACL was torn at different locations depending on the patients' age. These data provide more information on the potential application for ACL preservation in pediatric and adolescent patients. Future studies correlating these findings with arthroscopy are needed before using MRI for preoperative planning of ACL preservation surgery. LEVEL OF EVIDENCE: Diagnostic level III.

Arthroscopic primary repair of the anterior cruciate ligament: what the radiologist needs to know.

Recently, there has been a renewed interest in primary repair of proximal anterior cruciate ligament (ACL) tears. Magnetic resonance imaging (MRI) plays an important role in preoperative patient selection and in postoperative ligament assessment. Knowledge of the imaging factors that make patients candidates for primary ACL repair, namely proximal tear location and good tissue quality, can help radiologists provide information that is meaningful for surgical decision making. Furthermore, an understanding of the surgical techniques can prevent misinterpretation of the postoperative MRI. This article reviews preoperative MRI characterization of ACL injuries, techniques of arthroscopic primary ACL repair surgery and examples of postoperative MRI findings.

Clinical Outcomes of Arthroscopic Primary Repair of Proximal Anterior Cruciate Ligament Tears Are Maintained at Mid-term Follow-up.

PURPOSE: To assess the mid-term clinical outcomes in patients with proximal avulsion anterior cruciate ligament (ACL) tears undergoing arthroscopic primary repair with suture anchors. METHODS: The first 11 consecutive patients with proximal avulsion tears treated with arthroscopic primary repair were evaluated at mid-term (minimum 5-year) follow-up. Physical examination was performed; laxity examination consisting of the Lachman, pivot-shift, and anterior drawer tests was performed; and patients were asked to complete the Lysholm, modified Cincinnati, Single Assessment Numeric Evaluation, and International Knee Documentation Committee (IKDC) questionnaires. RESULTS: Of the 11 patients, 10 were seen at a mean follow-up of 6.0 ± 1.5 years (range, 4.8-9.2 years). One patient was lost to follow-up, in whom failure had already occurred at short-term follow-up. One additional patient underwent reoperation for a medial meniscus tear and also had a partial ACL tear; this patient was clinically stable at last follow-up. All patients had full range of motion. Nine patients had negative Lachman and negative pivot-shift examination findings (IKDC score of A), and 1 patient had a 1A Lachman result and 1+ pivot-shift result (IKDC score of B). The mean Lysholm score was 96.0 ± 4.5 (range, 88-100); modified Cincinnati score, 95.6 ± 7.4 (range, 80-100); Single Assessment Numeric Evaluation score, 95.4 ± 5.4 (range, 85-100); preinjury Tegner score, 7.2 ± 1.2 (range, 5-9); postoperative Tegner score, 6.6 ± 1.8 (range, 3-9); and IKDC subjective score, 92.3 ± 11.3 (range, 64-100). CONCLUSIONS: The clinical outcomes of arthroscopic primary repair of proximal ACL tears with suture anchors are excellent and are maintained at mid-term follow-up in a carefully selected subset of patients with proximal tears and excellent tissue quality. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Preoperative magnetic resonance imaging predicts eligibility for arthroscopic primary anterior cruciate ligament repair.

PURPOSE: To assess the role of preoperative magnetic resonance imaging (MRI) on the eligibility for arthroscopic primary anterior cruciate ligament (ACL) repair. METHODS: All patients undergoing ACL surgery between 2008 and 2017 were included. Patients underwent arthroscopic primary repair if sufficient tissue length and quality were present, or they underwent single-bundle ACL reconstruction. Preoperative MRI tear locations were graded with the modified Sherman classification: type I (>90% distal remnant length), type II (75-90%), or type III (25-75%). MRI tissue quality was graded as good, fair, or poor. Arthroscopy videos were reviewed for tissue length and quality, and final treatment. RESULTS: Sixty-three repair patients and 67 reconstruction patients were included. Repair patients had more often type I tears (41 vs. 4%, p < 0.001) and good tissue quality (89 vs. 12%, p < 0.001). Preoperative MRI tear location and tissue quality predicted eligibility for primary repair: 90% of all type I tears and 88% of type II tears with good tissue quality were repaired, while only 23% of type II tears with fair tissue quality, 0% of type II tears with poor tissue quality, and 14% of all type III tears could be repaired. CONCLUSIONS: This study showed that tear location and tissue quality on preoperative MRI can predict eligibility for arthroscopic primary ACL repair. These findings may guide the orthopaedic surgeon on the preoperative assessment for arthroscopic primary repair of proximal ACL tears. LEVEL OF EVIDENCE: Level IV.

Primary repair of the anterior cruciate ligament: A paradigm shift.

Over the last century, many surgical treatments have been developed in the orthopedic field, including treatments of anterior cruciate ligament (ACL) injuries. These treatments ideally evolve in a process of trial and error with prospective comparison of new treatments to the current treatment standard. However, these evolutions are sometimes not linear and periodically undergo paradigm shifts. In this article, we review the evolution of ACL treatment and explain how it underwent a paradigm shift. Open primary ACL repair was the most common treatment in the 1970s and 1980s, but because multiple studies noted deterioration of outcomes at mid-term follow-up, in addition to several randomized clinical trials (RCTs) that noted better outcomes following ACL reconstruction, the open primary repair technique was abandoned. At the end of the primary repair era, however, several studies showed that outcomes of open primary repair were good to excellent and did not deteriorate when this technique was selectively performed in patients with proximal ACL tears, whereas primary repair led to disappointing and unpredictable results in patients with mid-substance tears. Unfortunately, enrollment of patients in the aforementioned RCTs was already finished, ultimately leading to abandoning of open primary repair, despite the advantages of ligament preservation. In this review, we discuss (I) why the evolution of ACL treatment underwent a paradigm shift, (II) which factors may have played a role in this and (III) what the future role of arthroscopic primary ACL repair is in the evolution of ACL treatments.