PURPOSE:To investigate the association between patient characteristics (age, sex, and body mass index), the timing of posterior cruciate ligament reconstruction (PCLR), and the prevalence of concomitant cartilage and meniscal injuries. METHODS:Patients who underwent primary isolated PCLR between August 2016 and July 2024 were included. The presence of cartilage and meniscal injuries was confirmed via arthroscopic evaluation. The status of cartilage was, meanwhile, graded intraoperatively according to the International Cartilage Repair Society classification. Multivariable logistic regression analyses were performed to identify independent risk factors associated with both any-grade cartilage injuries and specifically high-grade (grades III-IV) cartilage injuries. RESULTS:A total of 1003 patients (787 males and 216 females) with a mean age of 33.18 years who underwent primary PCLR were retrospectively reviewed. Longer time from injury to surgery, particularly exceeding 24 months, was significantly associated with a higher risk of patellofemoral cartilage injury (odds ratio [OR], 1.794; P = .016), lateral compartment cartilage injury (OR, 2.141; P = .016), medial compartment cartilage injury (OR, 3.105; P < .001), and medial meniscal injury (OR, 1.990; P = .041) compared with PCLR performed within 3 months of injury. Additionally, older age significantly increased the prevalence of all cartilage and meniscal injuries (P < .001). Increased body mass index was independently associated with a higher incidence of patellofemoral cartilage injury (P = .006). Subgroup analysis revealed that patients with time from injury to surgery exceeding 24 months reported higher preoperative visual analog scale scores (P = .016). CONCLUSIONS:The incidence of concomitant injuries were 43.87% for patellofemoral cartilage, 10.87% for lateral compartment cartilage, 15.15% for medial compartment cartilage, 8.28% for lateral meniscus, and 10.47% for medial meniscus. Furthermore, delayed PCLR, especially beyond 24 months postinjury, coupled with older age and higher body mass index, were all crucial factors related to a higher prevalence of cartilage and meniscal injuries following grade III PCL injuries. LEVEL OF EVIDENCE:Level III, retrospective cohort study.

PURPOSE:To determine the maximal outcome improvement (MOI) thresholds for International Knee Documentation Committee (IKDC) score and Lysholm score anchored by patients' willingness to undergo posterior cruciate ligament (PCL) reconstruction again and identify predictors of failure to achieve these thresholds. METHODS:A retrospective review was conducted on patients who underwent primary PCL reconstruction. MOI was defined as the percentage of postoperative improvement relative to maximum possible improvement. Receiver-operating characteristic analyses were performed to determine the MOI thresholds based on patients' willingness to undergo PCL reconstruction as assessed through an anchor question at final follow-up. Multivariable logistic regression analyses were performed to identify predictors of failure to achieve these thresholds. RESULTS:A total of 217 patients were included, with a median follow-up of 63 months (range: 36-84 months). MOI thresholds were 34.5% for IKDC score (area under curve = 0.837) and 37.2% for Lysholm score (area under curve = 0.825), where the latter was calculated after excluding 11 patients with perfect preoperative scores. The proportions of patients achieving the MOI thresholds were 68.7% for IKDC score and 56.3% for Lysholm score. Independent predictors of failure to achieve these MOI thresholds included older age (odds ratio [OR] = 0.952), female sex (OR = 0.166), chronic injury (>12 months; OR = 0.377), and higher preoperative IKDC score (OR = 0.947). For Lysholm score, significant predictors included female sex (OR = 0.403), chronic injury (OR = 0.452), and higher preoperative Lysholm score (OR = 0.968). CONCLUSIONS:MOI thresholds for patients' willingness to undergo PCL reconstruction were 34.5% (IKDC score) and 37.2% (Lysholm score), achieved by 68.7% and 56.3% of patients, respectively. Older age, female sex, chronic injury (>12 months), and higher preoperative patient-reported outcome scores were negative predictors of achieving these MOI thresholds. LEVEL OF EVIDENCE:Level IV, retrospective case series.

Background: Anterior cruciate ligament reconstruction (ACLR) using hamstring tendon (HT) autografts faces persistent challenges of graft failure, especially in patients with high internal rotational tibial subluxation (IRTS). Hypothesis: Patients with high IRTS who undergo HT autograft ACLR with suture tape augmentation (STA) will have lower graft failure rates and superior clinical outcomes as compared with those without STA. Study Design: Cohort study; Level of evidence, 3. Methods: This retrospective cohort study included patients with high IRTS—defined as lateral minus medial anterior tibial subluxation >5.8 mm based on prior studies—who underwent primary ACLR using HT autografts with STA and had a minimum follow-up of 3 years. Propensity score matching (1:1) was performed to identify a control group of patients with similarly high IRTS who underwent HT ACLR without STA. Postoperative outcomes were assessed by the International Knee Documentation Committee score, Lysholm score, and Tegner activity scale, as well as by return-to-sport status and graft failure. Clinically meaningful improvements were evaluated by the minimal clinically important difference, Patient Acceptable Symptom State, and substantial clinical benefit. Results: This study included 62 patients with high IRTS: 31 with STA and 31 matched controls. The mean IRTS was 6.6 mm (range, 5.9-8.9) in the STA group and 6.8 mm (range, 5.8-8.7) in the control group. The mean patient age was 32.9 years (range, 20-50), and the mean follow-up was 3.8 years (range, 3.1-5.0). At final follow-up, the STA group showed significantly higher proportions of patients achieving the minimal clinically important difference (93.5% vs 74.2%; P = .038), Patient Acceptable Symptom State (96.8% vs 74.2%; P = .012), and substantial clinical benefit (54.8% vs 25.8%; P = .020). The return-to-sport rate was also higher in the STA group (74.2% vs 48.4%; P = .037). Additionally, the STA group demonstrated a lower graft failure rate (0% vs 12.9%; P = .039). Conclusion: For patients with high IRTS, STA in ACLR with HT autografts is associated with improved clinical outcomes, a higher return-to-sport rate, and a lower risk of graft failure at midterm follow-up.

Background: There is a lack of evidence and continuous debate on whether femoral tunnel displacement substantially influences the clinical efficacy of medial patellofemoral ligament reconstruction (MPFL-R) in addressing recurrent patellar dislocation. Purpose: To investigate possible associations between inaccurate femoral tunnel placement during MPFL-R and clinical outcomes, with a specific focus on proximal tunnel malpositioning. Study Design: Cohort study; Level of evidence, 3. Methods: Patients who were diagnosed with recurrent patellar dislocation and underwent MPFL-R were retrospectively analyzed. A true lateral view on 3-dimensional computed tomography was obtained, and the distance from the center of the femoral tunnel to the Schöttle point (DF-to-S) was measured. Accordingly, femoral tunnels were divided into the suboptimal group (DF-to-S > 10 mm) and the optimal group (DF-to-S≤ 10 mm). Patient data were collected and pathoanatomic risk factors were evaluated. Clinical assessments included patient-reported outcome measures, including the International Knee Documentation Committee (IKDC), Kujala, Lysholm, and Tegner scores; subjective satisfaction; and postoperative complications. A subgroup analysis was performed between proximally malpositioned tunnels and tunnels lying in other directions. Results: A total of 112 patients (112 knees) were included, with 34 in the suboptimal group and 78 in the optimal group. Patient characteristics and pathoanatomic abnormalities were comparable between the 2 arms, with mean follow-ups of 52.90 ± 23.80 months and 60.14 ± 27.88 months in the suboptimal and optimal groups, respectively ( P = .259). At the final follow-up, inferior IKDC (76.3 ± 12.8 vs 85.9 ± 6.3; P < .001), Kujala (87.7 ± 9.3 vs 93.8 ± 4.9; P = .001), and Lysholm (87.0 ± 11.8 vs 94.5 ± 5.3; P = .001) scores and subjective satisfaction (8.2 ± 1.4 vs 9.3 ± 0.9; P < .001) were observed in the suboptimal group compared with the optimal group. Lower proportions of patients met the minimal clinically important difference for the IKDC (82.4% vs 100.0%; P = .001) and Lysholm (79.4% vs 98.7%; P = .001) scores in the suboptimal group compared with the optimal group. Subgroup analysis demonstrated that the final IKDC ( P = .002), Kujala ( P = .001), and Lysholm ( P = .001) scores and subjective satisfaction ( P = .031) were statistically worse in the proximally located group, with insignificant improvements compared with preoperative levels. The suboptimal group showed a higher rate of overall complications, and anterior knee pain was more often reported in the proximally located subgroup. Conclusion: Inaccurate femoral tunnel positioning was associated with inferior midterm subjective functional scores and a higher rate of postoperative complications after MPFL-R. Proximal displacement in particular was associated with adverse clinical outcomes.

Anterior cruciate ligament (ACL) rupture and patellar dislocation (PD) are common knee injuries. Dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) are widely used clinical diagnostic tools. The aim was to investigate the characteristics of knee bone mineral density (BMD) in patients with ACL rupture and PD and to explore the relationship between BMD and Hounsfield unit (HU) values. This prospective cross-sectional study included 32 ACL rupture and 32 PD patients assessed via DXA and CT. BMD and CT measurements were taken from regions of interest in the femoral and tibial condyles. Statistical analyses included t-tests and mixed-effects models. The results showed that BMD in the PD group was significantly lower than in the ACL group (p < 0.05). The HU values of cortical bone in the femur and tibia differed significantly between the ACL group and the PD group (p < 0.05). The BMD of the femur and tibia showed significant correlations with the HU values of cancellous bone and cortical bone (p < 0.05). The conclusion was that PD patients had lower BMD and HU values in the femur and tibia compared to patients with ACL ruptures, particularly in the cortical bone of the tibia, and there was a strong correlation between HU value and BMD.

Diffuse-type tenosynovial giant cell tumor (dTGCT) is a destructive but rare benign proliferative synovial neoplasm. Although surgery is currently the main treatment modality for dTGCT, the recurrence risk is up to 50%. Therefore, there is a great need for effective drugs against dTGCT with minor side effects. The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling plays a central role in rheumatoid arthritis (RA), a disease with similar characteristics as dTGCT, but its function in dTGCT remains unknown. dTGCT fibroblast-like synoviocytes (FLS) and macrophages were isolated from 10 synovial tissue samples from dTGCT patients for the screening and validation of the five clinically approved JAK inhibitors to treat RA against dTGCT. Cell viability, cell death, inflammation and the activity of the JAK family members of cultured dTGCT FLS (both 2-D and 3-D) and macrophages were investigated for the efficacy of the JAK inhibitors. Here, we found that similar to RA, JAK/STAT signaling was markedly activated in the dTGCT synovium. Of the 5 JAK inhibitors, peficitinib was shown to have the most potency in addressing some of the pathological responses of dTGCT FLS and macrophages. The potency of peficitinib was much higher than pexidartinib, which is the only FDA-approved drug for dTGCT. Mechanistically, peficitinib inhibited tyrosine kinase 2 (TYK2), a JAK family member necessary for the pathological progression of dTGCT FLS and macrophages. In summary, we not only revealed JAK/STAT (especially TYK2) signaling as the major mechanism underlying dTGCT, but also identified peficitinib as a promising drug against dTGCT.

Patients with simultaneous ruptures of the patellar tendon (PT) and anterior cruciate ligament (ACL) underwent PT repair and ACL reconstruction in a single or staged surgery. However, due to the limited cases, the design of previous studies was mostly case report with varying conclusions regarding recommended surgical strategy selection, the optimal surgical strategy remains a subject of debate. We conducted a retrospective case series and literature review, including 10 cases from local institution and 27 cases from 17 studies. Demographic information, injury causes, surgical strategies, combined injuries, whether to return to (pre-injury level) sports, postoperative complications, Lysholm score and International Knee Documentation Committee (IKDC) score were identified retrospectively or reviewed from previous studies. The Fisher’s exact test was used to compare the incidence of postoperative complications between different surgical strategy groups, and linear logistic regression was used to analyze factors influencing postoperative knee function scores. Of the 37 patients, 15 patients (40.5

Purpose:The purpose of this study was to evaluate the accuracy of femoral tunnel location, post-operative pain management, functional rehabilitation and clinical outcomes in medial patellofemoral ligament (MPFL) reconstruction using all-arthroscopic technique. Methods:Between 2020 and 2021, 160 patients with recurrent patellar dislocation undergoing MPFL reconstruction were categorized into control (traditional surgery) and study (all-arthroscopic technique) groups. Femoral tunnel accuracy was assessed via computed tomography scans, pain management, functional rehabilitation, knee range of motion and daily activities were evaluated up to 6 months post-operatively. Knee function was assessed using Kujala and Lysholm scores at post-operative 12 months. Results:Seventy-one patients in the control group and 69 patients in the study group reached the final follow-up with no demographic differences. Follow-up duration was 12.65 ± 0.68 vs 12.77 ± 0.73 months in the control and study groups (p = 0.3145). The intra-class correlation coefficient was excellent (r = 0.97). In femoral tunnels, 93.5% in the control group and 92.4% in the study group were correctly localized. In patellar tunnels, 96.1% in the control group and 96.2% in the study group were correctly localized (p > 0.9999). Post-operative strong opioid analgesics were used 25.9 ± 31.0 versus 12.0 ± 22.2 mg/day in the control and study groups (p = 0.0016). The pain score was 3.4 ± 1.1 versus 2.7 ± 1.2 in the control and study groups (p = 0.0006) during post-operative functional rehabilitation. Time to resume daily living was 8.2 ± 0.6 versus 7.6 ± 0.6 weeks in the control and study groups (p < 0.0001). Time to resume low-intensity exercise was 12.3 ± 0.6 versus 11.7 ± 0.6 weeks in the control and study groups (p < 0.0001). In the more than 1-year follow-up, no significant difference was found in the Kujala and Lysholm scores. Conclusions:The all-arthroscopic technique for MPFL reconstruction in recurrent patellar dislocation ensures precise femoral tunnel placement. It offers advantages in early post-operative pain management and functional recovery, enabling faster rehabilitation compared to traditional non-all-arthroscopic techniques. Level of Evidence:Level III.

Background:Arthroscopic loose-body removal and synovectomy are recommended for the treatment of knee synovial chondromatosis (SC). However, there are limited data on clinical outcomes and survivorship after arthroscopic treatment for knee SC. Purposes/Hypothesis:The purpose was to evaluate the clinical outcomes and survivorship of arthroscopic loose-body removal and synovectomy in patients with knee SC, as well as to investigate the potential effect of concomitant chondral lesions on these outcomes. It was hypothesized that arthroscopic treatment for knee SC could yield satisfactory clinical outcomes, with concomitant chondral lesions negatively affecting clinical efficacy. Study Design:Case series; Level of evidence, 4. Methods:A consecutive cohort of patients diagnosed with knee SC and treated with arthroscopy between 2016 and 2022 was included in the study. Patient-reported outcomes (PROs) were collected preoperatively and at the final follow-up, including the Knee injury and Osteoarthritis Outcome Score, the subjective International Knee Documentation Committee (IKDC) score, the Lysholm score, and the visual analog scale for pain score. Data on arthroscopic findings, patient satisfaction, complications, and survivorship rates were also documented. The percentage of patients achieving the minimal clinically important difference (MCID) was calculated. Clinical outcomes were then compared between patients with and without chondral lesions identified during arthroscopy. Results:A total of 51 patients (54 knees) were included in the study, with a mean age at surgery of 42.3 ± 14.7 years and a mean follow-up period of 5.6 years. All PROs showed significant improvements at the final follow-up (P < .001), with >90% of patients achieving the MCID. Six knees (11.1%) experienced symptomatic recurrence confirmed by magnetic resonance imaging, and 3 knees (5.6%) underwent reoperation. The survivorship rates free from recurrence and reoperation were 85.1% and 93.9% at 8 years, respectively. At the final follow-up, no significant differences were found between knees with (n = 32) and without (n = 22) chondral lesions in all postoperative scores and survivorship rate. Conclusion:Arthroscopic treatment for knee SC yields favorable clinical outcomes with symptom relief and functional improvement. However, there remains a risk of recurrence and the need for reoperation. Additionally, patients with concomitant chondral lesions could achieve clinical outcomes and survivorship comparable to those of patients without chondral lesions.

BACKGROUND:Improvements in patient-reported outcome measure (PROM) scores have been widely documented after posterior cruciate ligament reconstruction (PCLR). Establishing clinically significant outcome (CSO) benchmarks for PROMs can enhance their clinical applicability. PURPOSE:To establish the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for PROMs after primary PCLR and identify the predictors of achieving them. STUDY DESIGN:Cohort study; Level of evidence, 3. METHODS:This retrospective study analyzed 157 patients who underwent primary PCLR between April 2016 and October 2019. PROM scores, including the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner score, were assessed preoperatively and at a minimum 5-year follow-up. The PASS and SCB were determined by anchor questions, while the MCID was calculated using the distribution-based method. Multivariable logistic regression analyses were performed to identify the predictors of achieving CSO benchmarks. RESULTS:The MCID, SCB, and PASS were 9.02, 16.09, and 80.46 for the IKDC score, respectively; 9.94, 11.00, and 85.00 for the Lysholm score, respectively; and 0.98, 2.00, and 5.00 for the Tegner score, respectively. Increased age was a negative predictor of achieving the MCID for the IKDC score as well as the PASS for both the IKDC score and Tegner score. Male sex positively predicted achieving CSO benchmarks for the IKDC score and Tegner score as well as the SCB for the Lysholm score. A higher preinjury Tegner score was positively associated with the achievement of CSO benchmarks for both the IKDC score and Lysholm score. A chronic injury (>6 months) was associated with the failure to achieve the MCID for the Tegner score, while a medial compartment cartilage lesion was associated with the failure to achieve the MCID for the IKDC score. Additionally, higher preoperative scores predicted failure to achieve the MCID and SCB for all PROMs but predicted success in achieving the PASS for the Tegner score. CONCLUSION:This study established MCID, SCB, and PASS values for the IKDC score, Lysholm score, and Tegner score after primary PCLR. Negative predictors of achieving these CSO benchmarks included increased age, chronic injury, and medial compartment cartilage lesion, while male sex and higher preinjury Tegner score were positive predictors. Additionally, higher preoperative scores served as negative predictors of achieving the MCID and SCB for the PROMs.

This study developed a new surgical robot for cruciate ligament reconstruction and compared its accuracy of bone tunnel placement with traditional surgical methods in combined posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) reconstruction. 8 human cadaver knees were used for robot-assisted combined PCL and ACL reconstruction, and three-dimensional (3D) computed tomography (CT) was performed after operation to confirm the bone tunnel information. Postoperative 3D CT images of eight patients completed by the same operator with conventional techniques were also acquired. The operation time, bone tunnel position and length were measured and compared between robotic and conventional surgery. Regarding the tunnel position, there was no significant difference between the planned and actual tunnels in robotic surgery and the anatomical site of the cruciate ligament (P > 0.05). However, there are significant differences between robotic and conventional surgery (P < 0.001). Compared with traditional surgery, the robotic surgery demonstrated higher accuracy in the drilling of the cruciate ligament tunnel. Regarding the length of the cruciate ligament tunnel, no statistically significant discrepancy was observed between the actual and planned tunnels (P > 0.05), with a maximum error of less than 2 mm. The robot was able to accurately control the length of the cruciate ligament tunnel. The robots can be used to assist in combined ACL and PCL reconstruction with higher accuracy than traditional surgery. It is a potentially powerful tool to enhance cruciate ligament reconstruction surgery.

Purpose:To construct a centre-specific machine learning (ML) prediction model based on preoperative factors. It was hypothesised that the ML prediction model would accurately predict whether patient-reported outcome scores (PROs) over at least 2 years would reach the minimal clinically important difference (MCID). Methods:A retrospective analysis was performed on mixed-type femoroacetabular impingement syndrome (FAIS) patients who had hip arthroscopy at our institution between 2016 and 2018. The primary outcome was the rate of achieving MCID in PROs assessed at least 2 years after surgery, PROs included the hip outcome score-activities of daily living (HOS-ADL), modified Harris Hip Score (mHHS), visual analogue scale (VAS) for pain and international hip outcome tool-12 (iHOT-12), assessed at a minimum of 2 years postoperatively. Preoperative patient features were selected using the least absolute shrinkage and selection operator (LASSO) algorithm. Three ML models were constructed using balanced sample data and optimal feature subsets: logistic regression (LR), support vector machine (SVM) and random forest (RF). Model performance was assessed using the area under the receiver operating characteristic curve (AUROC) and the concordance index (C-index). Model interpretations were conducted using the SHapley Additive explanation (SHAP) method. Results:A total of 210 patients (48.1% female) were included. The LR, SVM, RF models had AUROC 0.76 (0.61-0.83), 0.89 (0.80-0.94), 0.99 (0.98-1.00), respectively, and C-index 0.74 (0.65-0.82), 0.86 (0.81-0.90), 0.95 (0.93-0.96), respectively. Preoperative symptom duration, preoperative HOS-ADL, hip joint space and preoperative alpha angle were identified as the most important predictors. Conclusion:Among the three ML prediction models, RF performed best in predicting whether PROs reached MCID, demonstrating excellent discriminative ability, calibration and robustness. This indicates that individualised and robust ML prediction models for outcome prediction based on preoperative factors are feasible even with limited amounts of centre-specific data. Level of Evidence:Level III.

The inheritance of recurrent patellar dislocation (RPD) is known, but the susceptible gene remains unidentified. Here, we performed the first whole exome sequencing (WES) cohort study to identify the susceptible genes. The results showed eight genes were associated with this disease. Notably, the carboxypeptidase D (CPD) gene showed the highest relevance based on its gene function and tissue expression. Single-cell sequencing results indicate that the CPD gene is involved in the pathophysiological process of RPD through granulocytes. Implicated pathways include nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and Wnt/β-catenin signaling, potentially influencing CPD's role in RPD pathogenesis. This study identified the susceptible gene and investigates the potential pathogenesis of RPD, which provided a new prospect for the understanding of RPD. Besides, it would offer the theoretical basis for disease prevention and genetic counseling.

BACKGROUND:To perform anatomical anterior cruciate ligament reconstruction (ACLR), tunnels should be placed relatively higher in the femoral anterior cruciate ligament (ACL) footprint based on the findings of direct and indirect femoral insertion. But the clinical results of higher femoral tunnels (HFT) in double-bundle ACLR (DB-ACLR) remain unclear. The purpose was to investigate the clinical results of HFT and lower femoral tunnels (LFT) in DB-ACLR. METHODS:From September 2014 to February 2016, 83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR (group 1, n = 37) and LFT-ACLR (group 2, n = 46) according to the position of femoral tunnels. Preoperatively and at the final follow-up, clinical scores were evaluated with International Knee Documentation Committee (IKDC), Tegner activity, and Lysholm score. The stability of the knee was evaluated with KT-2000, Lachman test, and pivot-shift test. Cartilage degeneration grades of the International Cartilage Repair Society (ICRS) were evaluated on magnetic resonance imaging (MRI). Graft tension, continuity, and synovialization were evaluated by second-look arthroscopy. Return-to-sports was assessed at the final follow-up. RESULTS:Significantly better improvement were found for KT-2000, Lachman test, and pivot-shift test postoperatively in group 1 ( P >0.05). Posterolateral bundles (PL) showed significantly better results in second-look arthroscopy regarding graft tension, continuity, and synovialization ( P <0.05), but not in anteromedial bundles in group 1. At the final follow-up, cartilage worsening was observed in groups 1 and 2, but it did not reach a stastistically significant difference ( P >0.05). No statistically significant differences were found in IKDC subjective score, Tegner activity, and Lysholm score between the two groups. Higher return-to-sports rate was found in group 1 with 86.8% (32/37) vs. 65.2% (30/46) in group 2 ( P = 0.027). CONCLUSION:The HFT-ACLR group showed better stability results, better PL, and higher return-to-sports rate compared to the LFT-ACLR group.

Purpose: To evaluate the clinical outcomes following arthroscopic anterior cruciate ligament (ACL) reconstruction (ACLR) in patients over 60 years and to investigate the potential impact of preoperative osteoarthritis (OA) on these outcomes. Methods: A retrospective study included ACL-injured patients over 60 years who underwent primary arthroscopic ACLR between 2010 and 2020. The Lysholm score and the International Knee Documentation Committee (IKDC) score were assessed preoperatively and at the final follow-up. The Tegner activity scale was performed to evaluate patients' activity levels. Data on return to sports, patient satisfaction, subsequent injuries and complications were collected. Preoperative radiographs were used to grade OA according to the Kellgrene-Lawrence classification. Correlation analysis between OA and clinical outcomes was performed. The rates of achieving the minimal clinically significant difference and patient-acceptable symptoms state were documented. Results: A total of 37 patients were included in this study. The mean age at surgery was 62.3 +/- 2.3 years, with a mean follow-up of 6.3 +/- 3.2 years (range: 2.1-12.4). Patients showed statistically significant (all p < 0.001) improvements in the mean IKDC (38.9 +/- 9.4-66.8 +/- 12.5), Lysholm (48.8 +/- 15.4-83.0 +/- 12.8) and Tegner (1-3) scores. Fourteen patients (37.8%) returned to sports. No correlation was observed between the degree of preoperative OA and clinical outcomes (n.s.). Conclusion: Patients over 60 years with symptomatic ACL-deficient knees could benefit from ACLR, even when mild to moderate OA is present preoperatively. Level of EvidenceLevel IV.

Recurrent patellar dislocation is a common patellofemoral disease that affects active adolescents. The optimal surgical treatment of recurrent patellar dislocation in skeletally immature patients remains controversial. This Technical Note describes an arthroscopically assisted double-bundle medial patellofemoral ligament (MPFL) augmentation. Orthocord suture, with ideal strength and partial bioabsorbable characteristics, is used as the stabilizer to augment and protect the native MPFL during its biological healing. Under an arthroscope, patellar tunnels are created with Kirshner wire at the upper third point of the medial articular margin and the midpoint of the proximal articular margin. A physeal-sparing transosseous suture fixation technique is applied at the femoral attachment. Two femoral tunnels are made with half-circle cutting needle, which is pierced into the femoral origin of the MPFL and exits the posterior femoral cortex. After dynamic assessments of knee range of motion and patellofemoral congruence, free ends of the Orthocord suture bundle are tied together at the external opening of the femoral tunnel. Transosseous suture fixation balances the requirements of anatomic restoration, reliable fixation, and physeal preservation, and thus may provide a promising alternative to current algorithm of addressing recurrent patellar dislocation in pediatric population.

Purpose: To compare clinical and radiographic outcomes of medial patellofemoral ligament reconstruction (MPFL-R) and medial patellofemoral complex reconstruction (MPFC-R) for recurrent patellar dislocation. Outcome measures were compared based on the InsallSalvati index. Methods: Patients who were diagnosed with recurrent patellar dislocation and underwent either MPFL-R or MPFC-R (combined reconstruction of MPFL and medial quadriceps tendon -femoral ligament) were retrospectively analyzed. Group allocation was based on surgical procedure and patient characteristics were collected. Clinical assessments included patient -reported outcome measures (PROMs) and return -to -sports rates. Minimal clinically important difference analysis was performed. A subgroup analysis of PROMs was carried out between patients with an InsallSalvati index < 1.2 versus > 1.2. The patellar tilt angle, lateral patellar displacement, and bisect offset ratio were measured pre- and post-surgery. Functional failures and complications were assessed. Results: Overall, 70 patients (72 knees) in the MPFL-R group and 58 patients (61 knees) in the MPFC-R group were included. Patient characteristics were comparable between the groups. At a minimum follow-up of 24 (mean, 50.6 +/- 22.1) months, all PROMs were substantially improved ( P < .001), without signi fi cant intergroup differences. The percentages of patients reaching the minimal clinically important difference were similar after MPFL-R and MPFC-R: 98.6% versus 93.4% (International Knee Documentation Committee), 97.2% versus 98.4% (Lysholm), 98.6% versus 100% (Kujala), and 77.8% versus 72.1% (Tegner). The subgroup analysis based on patellar height and the return -to -sport rates also suggested comparable results. Radiographic evaluation demonstrated signi fi cantly smaller lateral patellar displacements ( P = .004) and bisect offset ratios ( P < .001) but similar patellar tilt angles after MPFC-R. Four (5.6%) patients receiving MPFL-R and 2 (3.3%) patients receiving MPFC-R reported recurrence of functional instability, without statistically signi fi cant difference. Conclusions: MPFC-R resulted in similar overall clinical and radiographic outcomes to MPFL-R in treating recurrent patellar dislocation. MPFC-R might not provide additional bene fi ts for patients with an InsallSalvati index > 1.2.

Background: The effects of single-bundle and double-bundle ACL reconstruction are still controversial and patients with different anatomy may need to choose different surgery. The aim of the study was to assess the relationship between graft maturation and clinical outcomes, identify the risk factors, and compare the results after single/double-bundle ACL reconstruction. Methods: A single-surgeon series of 147 patients with a median follow-up of 149.7 months (range, 144-189 months) underwent isolated primary ACL reconstruction (SB-ACLR group: n = 74; DB-ACLR group: n = 73). Clinical outcomes included the pivot shift test, IKDC, Lysholm, and Tegner scores. Signal intensity (SI) of the graft, and bone anatomy were also assessed. Results: Significant correlations between graft SI and last clinical outcomes were shown. Lateral tibial slope (LTS) (β = 0.09) and medial tibial slope (MTS) (β = 0.09), or their sum (STS) greater than 12° (β = 1.16) were determined as the risk factors of graft SI among SB-ACLR group patients. No independent risk factor for graft SI of patients in the DB-ACLR group was observed. Compared to the other three groups, the STS > 12° group in SB-ACLR showed significant differences in the clinical outcomes. Conclusions: Late graft SI is negatively correlated with the clinical outcomes. It might be affected by specific anatomic features in patients with SB-ACLR, including medial tibial slope, lateral tibial slope, and their sum, and mediated the effect on clinical outcomes. Patients with STS > 12° may consider choosing DB-ACLR to expect better long-term knee function after surgery. Trial registration: No. IRB00006761-2011097 and NCT03984474. Level of Evidence: Retrospective Study, Level III.

Recurrent patellar dislocation is a commonly encountered patellofemoral disease. Prompt surgical intervention is indicated for recurrent dislocation to restore patellofemoral stability. As one of the most preferred procedures, medial patellofemoral ligament (MPFL) reconstruction has been implemented on a large scale. Femoral tunnel placement remains a crucial technical issue during MPFL reconstruction and is critical to ensure the isometry and proper tension of the graft. Currently, visual–palpatory anatomic landmarks and fluoroscopy-guided radiographic landmarks comprise the main approaches to intraoperative femoral tunnel positioning. However, the accuracy of both methods has been questioned. This article introduces an arthroscopic femoral tunnel placement technique. Apart from traditional anteromedial and anterolateral portals, two auxiliary arthroscopic portals are specially designed. The adductor tubercle, the medial epicondyle and the posterior edge are selected as main anatomic landmarks and are directly visualized in sequence under arthroscope. The relative position between the femoral attachment of the MPFL and the three landmarks is measured on preoperative three-dimensional computed tomography, providing semi-quantified reference for intraoperative localization. This technique achieves minimally invasive tunnel placement without X-ray exposure, and especially suits obese patients for whom palpatory methods are difficult to perform.

Authors’ Response: We thank Dr Nizić for his interest for our recently published study. The tibial tubercle–Roman arch (TT-RA) distance has landmarks on the tibia and femur. Therefore, the translation of the tibia or the rotation of knee joints would alter the value of TT-RA distance. We have also performed studies to investigate the difference in the TT-RA distance between CT and MRI. We found that the value of TT-RA distance is affected by the rotation or flexion of the knee joint, which is also the case for the current gold standard tibial tubercle–trochlear groove (TT-TG) distance. Therefore, the TT-RA distance is a mixed imaging test. We do agree with Dr Nizić that a test of tibial tuberosity lateralization that is independent of femorotibial rotation may be a more reliable assessment. Some measurements such as tibial tuberosity–tibial intercondylar midpoint (TT-TIM) distance, or tibial tubercle–posterior cruciate ligament (TT-PCL) distance can evaluate pure tibial tubercle lateralization. However, the clinical value of these measurements remains uncertain. TT-PCL distance reflects the true lateralization of the tibial tubercle, and the TT-TG distance reflects the mixed tibial tubercle lateralization. We compared the clinical application value between TT-TG and TT-PCL distance in our previously published study and found the difference in the TT-PCL distance between patients with patellar dislocation and healthy controls to be only 1.11 mm. In addition, the TT-PCL distance was found to have a poor capacity to predict patellar dislocation (area under the receiver operating curve [AUC] 1⁄4 0.627). Therefore, the role of true tibial tubercle lateralization in the evaluation of patellar dislocation patients warrants further assessment. As mixed imaging tests, the TT-RA distance (AUC 1⁄4 0.8) and TT-TG distance (AUC 1⁄4 0.8) had higher capacity than TT-PCL distance (AUC1⁄4 0.6) to distinguish patients with patellar dislocation from healthy individuals, which indicate that the mixed imaging tests would be more suitable to evaluate patellar dislocation. As for the question of the accuracy of the TT-RA distance. We used the intraclass correlation coefficient to evaluate the precision of the measurements, and found that the TT-RA distance showed higher interand intraobserver reliability than the TT-TG distance (Table 2 of our study), especially in patients with patellar dislocation (Figure 6 of our study). When regarding the precision of TT-RA distance to distinguish patellar dislocation patients from healthy individuals, the AUC was comparable to that of the TT-TG distance (Figure 8 of our study). The sex difference of TT-RA distance was not investigated in the present study. It is hard to determine any sex-based differences in the TT-RA distance with a small sample size. Thank you for your kind thoughts and interest.