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Purpose: To investigate the changes in minimum joint space width (mJSW) caused by superficial medial collateral ligament (sMCL) transection during open-wedge high tibial osteotomy (OWHTO). Methods: This study included consecutive patients with a diagnosis of medial unicompartmental knee osteoarthritis who were scheduled for OWHTO between September 2020 and August 2022. Intraoperative fluoroscopic evaluations of mJSW were performed under neutral, valgus stress, and varus stress positions in knee extension and 20° of flexion before sMCL transection, after transection, and after plate fixation. Changes in mJSW and increases in valgus stress were calculated and compared using analysis of variance. Linear regression analysis was performed to investigate the related factors for increased mJSW after transection. Results: We included 44 knees in 43 patients in the final statistical analysis. The maximum mJSW occurred during valgus stress after sMCL transection at 20° of flexion and returned to baseline after plate fixation. Under the valgus stress condition, mean mJSW before transection was 5.1 ± 0.9 mm in extension and 5.5 ± 1.1 mm at 20° of flexion. It increased significantly after transection to 7.8 ± 1.4 mm (P < .001) and 9.2 ± 2.1 mm (P < .001), respectively. Regression analysis showed that increased mJSW after transection in extension positively correlated with the knee extension angle (P = .032). Overall, mJSW increased with sMCL transection regardless of the preoperative condition. Conclusions: Transection of the sMCL in OWHTO effectively enlarged the mJSW to 9.2 mm, which was 3.8 mm greater than that before transection, facilitating medial meniscal procedures. After plate fixation, the mJSW returned to pre-transection levels. Level of Evidence: Level Ⅳ, therapeutic case series.

Bone tunnel creation in the anatomical location is essential in anterior cruciate ligament (ACL) reconstruction with an autogenous graft and is commonly performed with a drill bit matched to graft diameter. Anatomic rectangular tunnel ACL reconstruction with a bone–patellar tendon–bone autograft has been developed to anatomically create bone tunnels inside the ACL footprints and has been reported to achieve excellent outcomes. To make the rectangular tunnel, the surgeon needs to dilate 2 adjacent bone tunnels after creation of 2 round tunnels with a drill bit, while the tunnel wall occasionally cracks during dilating. An ultrasonic (US) device was developed with improvement of output power and has been implemented with a rectangular shape blade in the field of arthroscopic surgery. This US device can provide a precise and effective bone cut compared to drills. We introduced this device to clinically create a rectangular tunnel during ACL reconstruction. The US device can be useful for rectangular femoral tunnel creation and can create a precise rectangular femoral tunnel in the ACL footprint.

Purpose: To quantify the cartilage surface profile visualized during arthroscopic surgery and examine its clinical utility by comparing the results of quantitative measurements with a conventional grading system. Methods: Fifty consecutive patients diagnosed with knee osteoarthritis and who underwent arthroscopic surgery were included in this study. A 4 K camera system was used, and the cartilage surface profile was visualized using the augmented reality imaging program. The highlighted image was displayed in 2 colors: black (the worn cartilage area) and green (the part where the cartilage thickness was maintained). The percentage of the green area was calculated using ImageJ and used as an index of cartilage degeneration. The quantitative value was statistically compared with the International Cartilage Repair Society (ICRS) grade as a conventional macroscopic evaluation. Results: In the quantitative measurement, the median percentage of the green area was 60.7 at ICRS grades 0 and 1 (interquartile range [IQR], 67.3-51.0), 47.2 at grade 2 (IQR, 54.1-39.2), 36.5 at grade 3 (IQR, 43.2-30.4), and 34.0 at grade 4 (IQR, 38.5-29.3). There was a significant difference between the macroscopic grades, except for Grades 3 and 4. There was a significant negative correlation between macroscopic evaluation and quantitative measurement (r = −0.672, P < .001). Conclusions: The quantitative measurement of the cartilage surface profile using the spectroscopic absorption technique was significantly correlated with the conventional macroscopic grading system and demonstrated fair to good inter-rater and intra-rater reliabilities. Level of Evidence: Level II, diagnostic (prospective cohort study).

Purpose: To investigate the clinical outcomes following meniscus allograft transplantation (MAT) to replace removed discoid lateral meniscus using intact lateral meniscus obtained from patients undergoing total knee arthroplasty for medial compartment osteoarthritis. Methods: Pediatric patients who underwent MAT secondary to partial or total meniscectomy due to discoid lateral meniscus between August 2010 and November 2018 were identified. Lateral menisci with bone blocks were transplanted arthroscopically. The demographic data, range of motion, meniscal allograft failure, which was defined as removal of an implanted meniscus, and complications were recorded. The Lysholm score and the Kellgren-Lawrence (KL) grade on radiographs were evaluated preoperatively and at final follow-up. The Knee injury and Osteoarthritis Outcome Score was evaluated in the final follow-up. Results: Eight patients who were symptomatic after discoid lateral meniscectomy were included. Donated allografts were harvested from adult patients aged between 64 and 78 years (mean 70.5 years). The mean age at previous meniscectomy and MAT were 10.5 and 18.1 years, respectively. All patients were followed up for a mean time of 5.2 years, and there were no cases of meniscus failure and complication. The Lysholm score significantly improved from preoperative to the final follow-up. Preoperatively, 6 and 2 knees were of KL grades II and III, respectively. At final follow-up, no increased KL grade was observed in 5 patients; however, an increase by 1 grade was observed in 2 patients and an increase by 2 grades was observed in 1 patient. The Knee injury and Osteoarthritis Outcome Scores at the final follow-up were 87.2 for pain, 87.9 for symptoms, 95.4 for activities of daily living, 79.4 for sports, and 65.6 for quality of life. Conclusions: Older lateral meniscus allografts obtained from knees of adult patients undergoing total knee arthroplasty and transplanted into younger patients with defects from discoid lateral meniscectomy resulted in improved Lysholm scores but no improvement in Tegner scores or knee motion. KL grades were unchanged in 5 of the 8 patients at the final follow-up. Level of Evidence: IV, therapeutic case series.

Osteochondritis dissecans (OCD) of the knee is a subchondral bone abnormality that results in the separation of the articular cartilage and bone with subsequent progression to osteoarthritis. Unstable OCD lesions should undergo fixation to preserve the natural contour of the articular surface. Although several fixation procedures have been reported, the appropriate procedure remains unknown. Because the bony portion of the OCD lesion is usually thin, it is difficult to fix firmly with conventional methods. We began fixing OCD lesions with knotless PushLock anchors and sutures and have obtained satisfactory results. This report describes this fixation method that uses the PushLock suture anchor to treat unstable OCD lesions. This procedure also can be applied for traumatic osteochondral fractures.

The number of anterior cruciate ligament (ACL) reconstructions in skeletally immature patients has been gradually increasing in recent years owing to the poor outcomes of conservative treatment. However, ACL reconstruction in children is a challenging procedure and may lead to severe complications, such as growth disturbance. Although double-bundle (DB) ACL reconstructions are preferable because of their superior clinical outcomes, there are few reports of DB ACL reconstruction in children with open epiphyses. In this Technical Note, an all-epiphyseal sparing DB ACL reconstruction technique, which is considered to help avoid growth disturbance, is described. This procedure does not create a thick tunnel and may facilitate subsequent revision surgery.

Medial patellofemoral ligament (MPFL) reconstruction usually involves hamstring autografts and is associated with donor-site morbidity. Excellent short-term results with MPFL reconstruction using synthetic materials have been reported. Although synthetics do not sacrifice autologous tissues, their material properties are significantly different from those of biological tissues. Therefore, accurate surgical procedures are required to achieve excellent results. The purpose of this report was to describe our surgical method for MPFL reconstruction using FiberTape and knotless SwiveLock anchors.