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AbstractPurposeThis study sought to develop and internally validate a machine learning model to identify risk factors and quantify overall risk of secondary meniscus injury in a longitudinal cohort after primary ACL reconstruction (ACLR).MethodsPatients with new ACL injury between 1990 and 2016 with minimum 2‐year follow‐up were identified. Records were extensively reviewed to extract demographic, treatment, and diagnosis of new meniscus injury following ACLR. Four candidate machine learning algorithms were evaluated to predict secondary meniscus tears. Performance was assessed through discrimination using area under the receiver operating characteristics curve (AUROC), calibration, and decision curve analysis; interpretability was enhanced utilizing global variable importance plots and partial dependence curves.ResultsA total of 1187 patients underwent ACLR; 139 (11.7%) experienced a secondary meniscus tear at a mean time of 65 months post‐op. The best performing model for predicting secondary meniscus tear was the random forest (AUROC = 0.790, 95% CI: 0.785–0.795; calibration intercept = 0.006, 95% CI: 0.005–0.007, calibration slope = 0.961 95% CI: 0.956–0.965, Brier’s score = 0.10 95% CI: 0.09–0.12), and all four machine learning algorithms outperformed traditional logistic regression. The following risk factors were identified: shorter time to return to sport (RTS), lower VAS at injury, increased time from injury to surgery, older age at injury, and proximal ACL tear.ConclusionMachine learning models outperformed traditional prediction models and identified multiple risk factors for secondary meniscus tears after ACLR. Following careful external validation, these models can be deployed to provide real‐time quantifiable risk for counseling and timely intervention to help guide patient expectations and possibly improve clinical outcomes.Level of evidenceIII.

Objectives:Introduction: Wrestling is a physically demanding sport with young athletes prone to anterior cruciate ligament (ACL) injuries. However, there is a paucity of data evaluating the results of ACL reconstruction (ACLR) in this cohort. Purpose: To assess patient-reported outcomes, reoperation rates, graft survival, and return to play (RTP) following ACLR in a large cohort of competitive wrestlers Methods: All competitive wrestlers (high school, collegiate, or professional) with a history of an ACLR at a single institution between 2000 and 2019 were retrospectively identified. Graft failure was defined as a re-tear determined by clinical or advanced imaging evaluation, and/or revision ACL reconstruction. All patients were contacted for determination of reinjury rates, current sport status, visual analog scale (VAS), International Knee Documentation Committee (IKDC) and Tegner activity scores. Results: 118 knees in 114 wrestlers were included at a median follow-up time of 5.8 years (IQR: 3.6 – 10.3). The median age was 17 years (15 – 18) with 116 (98%) males. ACLR was most often performed with bone-patellar tendon-bone (BTB) autograft (n = 64; 54%) or hamstring tendon (HT) autograft (n = 43; 36%). At final follow-up, 80% of athletes were able to RTP at a median of 273 days (IQR: 203 – 379). Graft failure occurred in 17 (14%) patients at a median time of 1.4 years (IQR: 0.8 – 4.7) after the index ACLR. BTB autograft demonstrated a lower failure rate compared to HT autograft (8% vs. 21%; P = 0.044). Kaplan-Meier survivorship free from graft failure for the entire cohort was 95.3% at 1 year, 92.5% at 2 years, 89.8% at 5 years, 84.6 at 10 years, 77.6 at 20 years. BTB autograft was associated with better survival than HT autograft up to 15 years after the index ACLR (90.4% vs. 76.3%; P = 0.030). Conclusions: Return to competitive wrestling was observed in 80% of athletes after ACLR, with 14% of wrestlers experiencing graft failure. BTB autograft reconstruction may serve as a more durable graft for competitive wrestlers with lower rates of failure when compared to HT autograft even up to 15 years after surgery. [Table: see text][Figure: see text][Figure: see text][Figure: see text]

Objectives: The medial patellofemoral ligament (MPFL) is the primary soft tissue restraint to lateral patellar translation and is often disrupted with a lateral patellar dislocation. Surgical management for recurrent patellar instability focuses on restoring MPFL function with repair or reconstruction techniques. Recent studies have favored reconstruction over repair, but no long-term, comparative studies are available in the literature. Methods: A total of 55 patients (58 knees) with recurrent lateral instability were treated between 2005 and 2012 with either MPFL repair or MPFL reconstruction. Exclusion criteria included prior or concomitant tibial tubercle osteotomy or trochleoplasty, and follow-up less than 8 years. Pre- and post-operative demographic, surgical, imaging and clinical data were recorded for each patient. Results: MPFL repair was performed on 26 patients (29 knees; 14 females, 15 males) at a mean age of 19.1 years. MPFL reconstruction was performed on 29 patients (29 knees; 18 females, 11 males) at a mean age of 18.2 years. Mean follow-up was 12.0 years (range 8.3-18.9). The reconstruction group had a significantly lower rate of recurrent dislocation compared to the repair group (14% vs 41%, p=0.019) at final follow up. There were no differences in the number of pre-operative dislocations (greater than or less than 3), degree of patellar facet chondromalacia, TT-TG distance, or Tegner scores. The reconstruction group had significantly more time from injury to surgery compared to the repair group (median, 1,460 days vs 627 days, p =0.007). There were no differences in post-operative Tegner, Lysholm or Kujala scores at final follow-up. Additionally, there were no differences in return to play rates (repair 80.8% vs reconstruction 75.0%, p=0.610) or reoperation rates (repair 20.7% vs reconstruction 13.8%, p=0.487). Conclusions: Repair of the MPFL leads to nearly 3-fold higher rate of recurrent patellar dislocation (41% vs. 14%) at long term follow-up compared to MPFL reconstruction. However, MPFL repair and reconstruction provide similar clinical results, return to play rates and reoperation rates. [Table: see text][Table: see text]

Objectives: Objectives: Previous analyses have characterized the incidence of lateral meniscus oblique radial tears (LMORT) commonly seen with ACL tears, and their impact on joint and meniscus stability in the presence of ACL deficiency. Purpose: To determine the clinically relevant kinematics associated with LMORT lesions untreated versus arthroscopic repair versus partial meniscectomy in combination with anterior cruciate ligament reconstruction (ACLR). Methods: Sixteen cadaver knees underwent robotic testing for anterior drawer (AD) and pivot shift (PS) simulations at multiple knee flexion angles in intact and ACL-deficient states, followed by sequential testing of arthroscopic ACL reconstruction (ACLR), creation of a LMORT 3 lesion, LMORT 3 repair, and partial meniscectomy (PM; n=8). The same testing sequence was performed for LMORT 4 lesions (n=8). Changes (Δ) from the intact state for anterior translation, internal rotation, and valgus displacements, as well as ultrasoundographic measurements of meniscal extrusion, were measured and comparatively analyzed. Results: ACLR restored kinematics in ACL-deficient knees to intact levels for all metrics tested. For AD, ACLR + LMORT3 tear and PM resulted in significantly greater anterior translation (0.8-2.1 mm differences) compared to ACL-intact at all angles ( P < 0.05) and compared to ACLR at 60 o and 90 o ( P < 0.014). For PS, ACLR + LMORT3 tear had significantly more anterior translation (1-1.4 mm differences) at 15 o than intact knees (P=0.041), and at 0 o and 15 o for PM ( P < 0.03). ACLR + LMORT4 tear and PM resulted in significantly greater anterior translation (0.9-2.3 mm differences) for AD ( P < 0.04) and PS testing ( P < 0.05) compared to intact and ACLR knees at all angles tested. ACLR+LMORT 3 repair and ACLR+LMORT4 repair restored kinematics to ACLR and intact levels at all angles tested. ACLR + LMORT3 tear ( P < 0.008) and both LMORT4 tear and PM ( P < 0.05) resulted in increased meniscal extrusion (1.8-11 mm differences) compared to intact and ACLR statuses at all tested angles for AD and PS while repairs restored meniscus stability to ACLR and intact levels. Conclusions: Untreated LMORT 3 and 4 tears increased anterior translation, pivot shift, and meniscus extrusion even after ACLR, while partial meniscectomy further exacerbated these detrimental effects. In contrast, arthroscopic side-to-side repair of LMORT lesions effectively restored measured knee kinematics. UPLOAD- https://planion-client-files.s3.amazonaws.com/AOSSM/blobs/6bf43418-abf1-49bd-b78b-cc0c501a2da0/1/AOSSM_Abstract_Images.docx UPLOAD- https://planion-client-files.s3.amazonaws.com/AOSSM/blobs/b0f0bf53-a166-4cec-bf73-176ea452b905/1/AOSSM_Abstract_CHART.docx

Background: Lytic or malpositioned tunnels may require bone grafting during revision anterior cruciate ligament reconstruction (rACLR) surgery. Patient characteristics and effects of grafting on outcomes after rACLR are not well described. Purpose: To describe preoperative characteristics, intraoperative findings, and 2-year outcomes for patients with rACLR undergoing bone grafting procedures compared with patients with rACLR without grafting. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 1234 patients who underwent rACLR were prospectively enrolled between 2006 and 2011. Baseline revision and 2-year characteristics, surgical technique, pathology, treatment, and patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale [Marx]) were collected, as well as subsequent surgery information, if applicable. The chi-square and analysis of variance tests were used to compare group characteristics. Results: A total of 159 patients (13%) underwent tunnel grafting—64 (5%) patients underwent 1-stage and 95 (8%) underwent 2-stage grafting. Grafting was isolated to the femur in 31 (2.5%) patients, the tibia in 40 (3%) patients, and combined in 88 patients (7%). Baseline KOOS Quality of Life (QoL) and Marx activity scores were significantly lower in the 2-stage group compared with the no bone grafting group ( P≤ .001). Patients who required 2-stage grafting had more previous ACLRs ( P < .001) and were less likely to have received a bone–patellar tendon–bone or a soft tissue autograft at primary ACLR procedure ( P≤ .021) compared with the no bone grafting group. For current rACLR, patients undergoing either 1-stage or 2-stage bone grafting were more likely to receive a bone–patellar tendon–bone allograft ( P≤ .008) and less likely to receive a soft tissue autograft ( P≤ .003) compared with the no bone grafting group. At 2-year follow-up of 1052 (85%) patients, we found inferior outcomes in the 2-stage bone grafting group (IKDC score = 68; KOOS QoL score = 44; KOOS Sport/Recreation score = 65; and Marx activity score = 3) compared with the no bone grafting group (IKDC score = 77; KOOS QoL score = 63; KOOS Sport/Recreation score = 75; and Marx activity score = 7) ( P≤ .01). The 1-stage bone graft group did not significantly differ compared with the no bone grafting group. Conclusion: Tunnel bone grafting was performed in 13% of our rACLR cohort, with 8% undergoing 2-stage surgery. Patients treated with 2-stage grafting had inferior baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting. Patients treated with 1-stage grafting had similar baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting.

Background: Lateral meniscal oblique radial tears (LMORTs) affect joint and meniscal stability in anterior cruciate ligament (ACL)–deficient knees. Purpose: To determine the clinically relevant kinematics associated with the most common posterior horn LMORT lesion types, types 3 (LMORT3) and 4 (LMORT4), untreated versus arthroscopic repair versus partial meniscectomy in combination with ACL reconstruction (ACLR). Study: Controlled laboratory study. Methods: Sixteen cadaveric knees underwent robotic testing for anterior drawer and pivot-shift simulations at multiple knee flexion angles in ACL-intact and ACL-deficient states, followed by sequential testing of arthroscopic ACLR, LMORT3 lesion, LMORT3 repair, and partial meniscectomy (n = 8). The same testing sequence was performed for LMORT4 lesions (n = 8). Results: ACLR restored kinematics in ACL-deficient knees to intact levels for all metrics tested. For anterior drawer, ACLR + LMORT3 tear and partial meniscectomy resulted in significantly greater anterior translation compared with ACL-intact at all angles ( P < .05) and compared with ACLR at 60° and 90° ( P < .014). For pivot shift, compared with ACL-intact knees, ACLR + LMORT3 tear resulted in significantly more anterior translation at 15° ( P = .041); and for ACLR + partial meniscectomy, at both 0° and 15° ( P < .03). ACLR + LMORT4 tear and partial meniscectomy resulted in significantly greater anterior translation for anterior drawer ( P < .04) and pivot-shift testing ( P < .05) compared with intact and ACLR knees at all angles tested. ACLR + LMORT3 repair and ACLR + LMORT4 repair restored kinematics to ACLR and intact levels at all angles tested. ACLR + LMORT3 tear ( P < .008) and both LMORT4 tear and partial meniscectomy ( P < .05) resulted in increased meniscal extrusion compared with intact and ACLR statuses at all tested angles for anterior drawer and pivot shift, while repairs restored meniscal stability to ACLR and intact levels. Conclusion: Untreated LMORT tears increased anterior translation, pivot shift, and meniscal extrusion after ACLR, while partial meniscectomy further exacerbated these detrimental effects in this cadaveric model. In contrast, arthroscopic side-to-side repair of LMORT lesions effectively restored measured knee kinematics. Clinical Relevance: LMORT lesions are common with ACL tears and adversely affect joint stability and meniscal extrusion. This study highlights the importance of repair of LMORT 3 and 4 lesions at the time of ACLR.

AbstractIntroduction Second anterior cruciate ligament (SACL) injuries are a devastating complication following return to sport (RTS). Appropriate and safe RTS criteria that reduce the risk of SACL injuries are needed. The goal of this study was to investigate the relationship between functional and isokinetic testing at 6 months following primary ACL reconstruction (ACLR) as risk factors for SACL injuries.Methods Patients with primary ACLR from 1990 to 2010 were identified. Those with 6-month postoperative functional and isokinetic testing and a minimum of 2-year follow-up were included. Functional testing included vertical jump, single-leg hop, and single-leg triple hop. Isokinetic testing included concentric quadriceps and hamstrings (HSs) strength at 60 and 180 degree/s speeds. Statistical analysis evaluated the significance of the various tests between those with and without a secondary tear.Results In total, 344 patients with a mean age of 26.0 ± 9.8 years at an average time of 9.1 ± 3.5 years of follow-up were analyzed. Fifty-nine patients (17%) experienced SACL injuries at an average time of 4.8 years following ACLR with 34 (58%) ipsilateral graft ruptures and 25 (43%) contralateral tears. Several isokinetic measures were significantly different between the NO SACL and the SACL groups: quadriceps 60 degree/s limb symmetry index (LSI) (75 vs. 82% p = 0.01), HS 60 degree/s LSI (92 vs. 97%, p = 0.04), quadriceps 180 degree/s involved/body weight (BW) (41 vs. 47%, p = 0.04), and HS 180 degree/s involved/BW (30 vs. 34%, p = 0.04). Patients with involved limb peak quadriceps torque value greater than 65 or 50% of BW (60 and 180 degree/s) had a 2.2 and 3.1 times higher risk of an SACL injury.Conclusions Patients with certain elevated isokinetic scores in the injured limb at 6 months after ACLR experienced a higher rate of subsequent ACL injuries than those who had lower peak torque. Although a quantitative only analysis may not be sufficient to determine RTS criteria, clinicians should caution high-performing patients about the risk of subsequent ACL injury.Level of Evidence Cohort study; 3.

Background: Wrestling is a physically demanding sport, with young athletes prone to anterior cruciate ligament (ACL) injuries. There is a paucity of data evaluating the results of ACL reconstruction (ACLR) in this cohort. Purpose: To assess return to sport (RTS), patient-reported outcomes, reoperation rates, and graft survival after ACLR in a large cohort of competitive wrestlers at midterm follow-up. Study Design: Case series; Level of evidence, 4. Methods: We identified all competitive wrestlers (club, high school, collegiate, or professional) with a history of an ACLR at a single institution between 2000 and 2019. Graft failure was defined as a retear (as determined via clinical or advanced imaging evaluation) and/or revision ACLR. All patients were contacted for determination of reinjury rates; current sport status; and pain visual analog scale, International Knee Documentation Committee, and Tegner activity scores. Results: Included were 107 knees in 103 wrestlers, with a median follow-up time of 5.9 years (interquartile range [IQR], 3.9-10.3 years). The median age was 17 years (IQR, 15-18 years), with 106 (99%) male patients, and the distribution of bone–patellar tendon–bone (BTB) and hamstring tendon (HT) autografts was 64 (60%) and 43 (40%), respectively. At final follow-up, 80% of athletes were able to RTP at a median of 280 days (IQR, 212-381 days). Graft failure occurred in 14 (13%) knees at a median time of 1.8 years (IQR, 0.7-5.3 years) after the index ACLR. BTB autograft demonstrated a lower failure rate compared with HT autograft (8% vs 21%; P = .044) and was associated with better survival compared with HT autograft up to 15 years after the index ACLR (90.4% vs 76.3%; P = .030). When compared by graft diameter, HT autografts of at least 7.5 mm were not associated with a lower graft failure than BTB constructs of all sizes ( P = .205). Conclusion: Return to competitive wrestling was observed in 80% of athletes after ACLR, with 14% of wrestlers experiencing graft failure. BTB autograft was associated with better survival than HT autograft.

Background: Proximal tibial osteotomy (PTO) is a well-established treatment for coronal deformity and focal cartilage defects. However, the utility of joint-preserving interventions must be weighed against potential effects on subsequent total knee arthroplasty (TKA). The purpose of this study was to determine the effect of PTO on subsequent TKA by comparing outcomes in patients with bilateral TKAs following unilateral PTO. Methods: Patients who underwent bilateral TKAs from 2000 to 2015 at a single institution and had previously undergone a unilateral valgus-producing PTO were reviewed. We evaluated 140 TKAs performed in 70 patients (24 female, 46 male) with a mean age at PTO of 50 ± 8 years. The patients underwent conversion to TKA at a mean of 14 ± 7 years following ipsilateral PTO and were followed for a mean of 25 ± 7 years (range, 6 to 40 years) following PTO. The Knee Society Score (KSS), Forgotten Joint Score-12 (FJS-12), subjective knee preference, and revision were compared between the PTO-TKA and contralateral TKA-only sides. Results: The PTO side demonstrated similar KSS Knee subscores (41 ± 16) compared with the contralateral side (39 ± 16, p = 0.67) immediately prior to arthroplasty. Patients had significant improvements in KSS (p < 0.001) after TKA, with clinically similar KSS values at 2 to 15 years of follow-up when knees were compared in a pairwise fashion (p = 0.10 to 0.83). Five PTO-TKA knees (7%) and 4 control TKA-only knees (6%) underwent revision at a mean of 5 years postoperatively (p = 0.76). The number of all-cause reoperations was approximately twice as high in PTO-TKA knees (13% compared with 6% in TKA-only knees, p = 0.24). At the time of final follow-up, PTO-TKA knees demonstrated similar FJS-12 scores (72 ± 26) compared with the contralateral knees (70 ± 28, p = 0.57). Nineteen percent of patients preferred the PTO-TKA knee, 19% preferred the contralateral TKA-only knee, and 62% stated that their knees were equivalent (p > 0.99). The final Tegner activity score was 2.5 ± 1.4. Conclusions: Long-term clinical function of TKA following PTO was excellent, with patients demonstrating comparable subjective outcomes and equivalent knee preference compared with the contralateral TKA-only knees. Further, well-matched studies are needed to evaluate long-term revision and reoperation rates following PTO-TKA. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: Prospective evaluation of clinical outcomes after posterior meniscal root repair utilizing a transtibial pullout technique is limited, and factors that may contribute to outcomes are unclear. Hypothesis: It was hypothesized that there would be an overall significant improvement in outcomes after root repair and that differences in clinical outcomes would correlate with age, body mass index (BMI), sex, and meniscal extrusion. Study Design: Case-control study; Level of evidence, 3. Methods: Consecutive patients undergoing transtibial medial or lateral meniscal root repair were enrolled prospectively at 2 orthopaedic centers between March 2017 and January 2019. Pre- and postoperative magnetic resonance imaging (MRI) were obtained to assess for meniscal healing, quantification of extrusion, articular cartilage grade, and subchondral bone changes. Patient-reported outcomes including International Knee Documentation Committee (IKDC) scores, Tegner activity scale, and visual analog scale (VAS) for pain were collected preoperatively and 2 years postoperatively. Patients were then subdivided by clinical and demographic characteristics to determine factors associated with clinical outcomes. Results: Included were 45 patients (29 female, 16 male; mean age, 42.3 ± 12.9 years; mean BMI, 31.6 kg/m 2 ) who underwent 47 meniscal root repairs (29 medial and 16 lateral; 2 had both). Significant improvements at 2-year follow-up were seen in IKDC score (41.1 vs 78.4; P < .001), Tegner activity level (3 vs 4; P < .001), and VAS pain (2.8 vs 0.7; P < .001). BMI, preoperative malalignment, cartilage status, and progressive meniscus extrusion (Δ = 0.7 mm) did not have a negative impact on IKDC and Tegner scores 2 years postoperatively. Age greater than or equal to 50 years and extrusion pre- and postoperatively were associated with decreased Tegner scores. Progressive meniscal extrusion was associated with a decreased overall improvement in Tegner scores. Conclusion: Transtibial root repair for medial and lateral posterior meniscal root tears demonstrated significantly improved clinical outcomes at 2 years postoperatively. Increased age, increased BMI, cartilage status, and meniscal extrusion did not have a negative impact on short-term functional outcomes (IKDC), but age greater than or equal to 50 years and extrusion negatively influenced patient activity level (Tegner). Registration: NCT03037242 ( ClinicalTrials.gov identifier).