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Abstract Purpose Post‐operative meniscal cyst formation occurs following all‐inside device meniscal repair. This study aimed to compare the incidence of cysts in patients who underwent meniscal repair with and without all‐inside suture devices. Methods This retrospective study included 227 knees that underwent meniscal repair between 2021 and 2022. The incidence of post‐operative meniscal cysts was compared between patients who underwent repair using an all‐inside suture anchor device (Group SA) and those who did not use an anchor (Group NA), based on post‐operative magnetic resonance imaging (MRI) findings. Risk factors, such as the number of anchors used, were investigated. Using a subgroup analysis, the incidence of meniscal cysts based on the type of device used was investigated. Results Groups SA and NA comprised 125 and 102 knees, respectively. Group SA had 11 cases of cysts (9% incidence), whereas Group NA had 7 cases (7% incidence), and no statistically significant difference was observed (p = 0.63). Symptomatic cysts were observed in two patients (1.6%) in Group SA, whereas none was observed in Group NA (0%); the difference was not significant (p = 0.50). Factors such as the number of anchors and sutures used and MRI timing were not identified as risk factors. Cyst incidence varied according to anchor type: Stryker AIR+ (4 out of 55, 7%), Smith & Nephew Fast‐Fix 360 (7 out of 56, 13%) and Arthrex Fiber Stitch (0 out of 26, 0%), with no significant difference found (p = 0.14). Conclusion The incidence of cysts in patients undergoing meniscal repair with an all‐inside suture anchor device was 9%, showing no significant difference compared with Group NA. Cyst incidence was not affected by device type. Level of Evidence Level III, retrospective comparative study.

Abstract Purpose Younger age and steep posterior tibial slope (PTS) have been reported as risk factors for graft failure after anterior cruciate ligament reconstruction (ACLR). Few studies have evaluated these risk factors simultaneously in a large cohort of patients undergoing double‐bundle ACLR (DB‐ACLR). Therefore, this retrospective study aimed to simultaneously investigate known risk factors such as PTS and age in DB‐ACLR, determine their thresholds and calculate odds ratios (ORs). Methods We investigated 482 knees that underwent DB‐ACLR with a follow‐up period of at least 2 years. Receiver operating characteristic analysis determined cut‐off values for age and PTS for graft failure. Subsequently, logistic regression analysis was conducted to evaluate the effects of age, sex, height, weight, laterality, surgical waiting period, pre‐operative sport type and level, meniscal injury, hyperextension, general joint laxity and PTS on graft failure. Results Graft failure was observed in 33 out of 482 knees (6.8%). Notably, the graft failure group was significantly younger (18.0 ± 5.0 years [standard deviation] vs. 30.4 ± 13.1 years, p

Abstract Purpose Restricted kinematic alignment (rKA) is a modified technique of kinematic alignment (KA) total knee arthroplasty (TKA) for patients with an outlier or atypical knee anatomy, striving to preserve the native knee joint line parallel to the ground in a bipedal stance. This study aimed to evaluate the accuracy of rKA TKA with a computed tomography (CT)‐based patient‐specific instrument (PSI) to achieve the preoperative plan with the joint line parallel to the ground level. Methods Using a CT‐based PSI, 74 closed‐leg standing long‐leg radiographs were obtained before and after rKA TKA. The hip‐knee‐ankle angle (HKA), joint line orientation angle (JLOA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) were measured. Bone resection accuracy was evaluated by postoperative HKA deviations from the planned alignment and joint line by postoperative JLOA deviations from the ground level. Results The mean postoperative JLOA and HKA were 2.1° valgus (range, standard deviation: 6.0° valgus to 3.0° varus, 2.0) and 2.6° varus (3.5° valgus to 12.5° varus, 3.2), respectively. Postoperative JLOA and HKA were within ± 3° of the planned alignment for 69% and 86% of cases, respectively. Conclusions Despite a static verification, we clarified how the joint line after rKA TKA was reproduced in the closed‐leg long leg radiographs to mimic the limb position during gait. However, this imaging method is not well‐established, and lack of long‐term survivorship and the relationship between joint line inclination and clinical outcomes represented limitations of this study. Level of evidence Level IV.

Abstract Purpose Although complete tear of the knee posterolateral corner (PLC) commonly occurs in combination with other knee ligamentous injuries, the incidence of isolated PLC injury was reported only 28% and overlooked in many cases. Nevertheless, an isolated PLC injury does not only provoke posterolateral instability, but also may be associated to hypermobile lateral meniscus. This study aims at showing the characteristics of isolated PLC injuries and to alert potential overlooked cases by describing their arthroscopic findings and clinical characteristics. Methods Seventy-one patients with a clinically proven isolated PLC injury who underwent knee arthroscopy were included in this study. Pre-operative symptoms and clinical signs at examination were recorded: Pain at the posterolateral aspect, feelings of instability, catching, locking; and for clinical signs: McMurray test, varus stress test in extension and at 30° of flexion, posterolateral drawer test at 30° and 80°, dial test at 30° and 80° of flexion. In terms of arthroscopic findings, systematic meniscal stability was performed to evaluate the presence of hypermobile lateral meniscus, “lateral drive through test” was also recorded in all cases. Results Positive Lateral Drive through test was found in 69 patients (95.8%). Hypermobile lateral meniscus was seen in all patients. Conclusions Hyper mobile lateral meniscus was concomitant with all isolated PLC injuries in our case series. As the typical arthroscopic characteristic, lateral drive through test positive were seen in 95.8%. In order to prevent overlooking this concomitant pathology, meticulous arthroscopic observation is crucial. Level of evidence Level IV.

Abstract Purpose Several studies have shown an excellent success rate of communication enlargement surgery for popliteal cysts (Baker’s cysts). Ultrasound-guided surgery can improve the accuracy of this procedure and may lead to better outcomes. This study describes a simple ultrasound-guided arthroscopic technique to manage popliteal cysts and reduce postoperative pain. Methods After routine arthroscopic observation with a standard 2-portal approach, the arthroscope is redirected toward the posteromedial compartment from the anterolateral portal through the intercondylar notch. A posteromedial portal is then placed at this view. Subsequently, a contrast dye (indigo carmine) is injected into the popliteal cyst percutaneously using ultrasonography. This procedure makes it easier to find a capsular fold or valvular opening. The valvular opening between the semimembranosus and medial gastrocnemius is enlarged with a shaver and radiofrequency ablation. Cystectomy is not performed in any case. Finally, the irrigation fluid is suctioned, and the reduced cyst is visualized by ultrasound. Additionally, a periarticular multimodal drug injection is administered into the septum and inner wall of the cyst under ultrasound guidance. Conclusions Ultrasound-guided arthroscopic surgery for popliteal cysts can ensure reproducibility and be effective for postoperative pain relief. Thus, this combined procedure may be an optimal treatment option.

Abstract Background/Purpose Hamstring tendon autografts are commonly used for double-bundle anterior cruciate ligament reconstruction (DB-ACLR). If the volume of the semitendinosus (ST) tendon is insufficient, the gracilis (G) tendon is also harvested. Additional harvesting of the G autograft can affect patients’ short-term postoperative outcome, such as muscle recovery; thus, preoperative information about whether an additional G autograft is needed would be useful. The purpose of this study was to investigate whether preoperative measurement of the ST tendon using ultrasonography could inform the intraoperative decision to harvest the G tendon. Methods We enrolled 20 patients (13 men and seven women) who underwent DB-ACLR between October 2017 and March 2019. The mean patient age was 28.5 years. The ipsilateral ST tendon was measured using ultrasonography before surgery. Measurements included the diameter and breadth of the short-axis image. The cross-sectional area (CSA) was calculated from these measurements. During surgery, when two grafts with diameters of ≥ 5.0 mm could not be made, the G tendon was also harvested. Patients were categorized into two groups: the ST group where only the ST tendon was harvested, and the semitendinosus gracilis tendon (STG) group where the ST and G tendons were both harvested. The CSA value was compared between the two groups, and the cutoff value was calculated. Results In the ST group (n = 8), the mean diameter and breadth of the semitendinosus tendon were 4.21 and 2.34 mm, respectively. In the STG group (n = 12), the mean diameter and breadth of the ST tendon were 3.39 and 1.78 mm, respectively. The CSAs calculated for the ST group and the STG group were 7.74 mm2 and 4.79 mm2, respectively. A cutoff value of 7.0 mm2 was found to correspond to a specificity and sensitivity to harvest the G tendon of 87.5% and 75.0%, respectively. Conclusions The preoperative CSA of the ST tendon determined using ultrasonography can, therefore, be informative for deciding whether to harvest the G tendon for DB-ACLR. The results of this study provide valuable information for graft selection in anterior cruciate ligament reconstruction. Level of Evidence IV (Retrospective case series design).

Abstract Purpose There are concerns that malalignment in total knee arthroplasty (TKA) occurs with less experienced surgeons. This study investigates the influence of surgical experience on TKA outcomes. Materials and methods Nineteen patients (38 knees) who underwent bilateral TKA between 2011 and 2015 were included. A supervisor performed knee replacements associated with lower Knee Society Scores (KSS); trainee surgeons operated on the other knee. Knees were categorized into two groups: operations by the supervisor (group S) versus operations by trainee surgeons (group T). Range of motion (ROM), KSS, operative time, hip–knee–ankle angle, and femoral and tibial component angle were evaluated. Results The mean operative time was 92.5 min in group S and 124.2 min in group T (p