Objective To investigate whether the outlet of the femoral tunnel will cause iatrogenic injury to the medial collateral ligament (MCL) during posterior cruciate ligament reconstruction (PCLR) and estimate the safe angle of femoral tunnel placement. MethodsThirteen formaldehyde-soaked human knee joint specimens were used, 8 from men and 5 from women; the donors’ age ranged from 49 to 71 years, with an average of 61 years. First, the medial part of the femur was carefully dissected to clearly expose the region of the MCL course and attachment on the femoral medial aspect and to outline the anterior margin of the region with a marked line. The marked line divided the medial femoral condyle into an area with an MCL course and a bare bone area which is regarded relatively safe for no MCL course. Then, the posterior cruciate ligament (PCL) was cut to identify the femoral attachment of the PCL. After the knee joint was fixed at a 120° flexion angle, the process of femoral tunnel preparation for the PCL single-bundle reconstruction was simulated. The inside-out technique was used to drill the femoral tunnel from the PCL femoral footprint inside the knee joint with an orientation to exit the medial condyle of the femur, and the combination angle of the two planes, the axial plane and the coronal plane, was adapted to the process of drilling femoral tunnels at different orientations. The following 15 angle combinations were used in the study: 0°/30°, 0°/45°, 0°/60°, 15°/30°, 15°/45°, 15°/60°, 30°/30°, 30°/45°, 30°/60°, 45°/30°, 45°/45°, 45°/60°, 60°/30°, 60°/45°, 60°/60° (axial/coronal). The positional relationship between the femoral tunnel outlet on the femoral medial condyle and the marked line was used to verify whether the tunnel drilling angle was a risk factor for MCL injury or not, and whether the shortest distance between the femoral exit center and the marked line was affected by the various angle combinations. Furthermore, the safe orientation of the femoral tunnel placement would estimated. ResultsWhen creating the femoral tunnel for PCLR, there was a risk of damage to the MCL caused by the tunnel outlet, and the incidence was from 0 to 100%; when the drilling angle of the axial plane was 0° and 15°, the incidence of MCL damage was from 69.23% to 100%. There was a significant difference in the incidence of MCL damage among femoral tunnels of 15 angle combinations (χ2=148.195, P<0.001). By comparison between groups, it was found that when drilling femoral tunnels at 5 combinations of 45°/45°, 45°/60°, 60°/30°, 60°/45°, and 60°/60° (axial/coronal), the shortest distances between the tunnel exit and the marked line were significantly different than 0°/45°, 0°/60°, 15°/45°, 15°/60°, and 30°/30° (axial/coronal) (P<0.05). Additionally, after comparing the median of the shortest distance with other groups, the outlets generated by these 5 angles were farther from the marked line and the posterior MCL. ConclusionThe creation of the femoral tunnel in PCLR can cause iatrogenic MCL injury, and the risk is affected by the tunnel angle. To reduce the risk of iatrogenic injury, angle combinations of 45°/45°, 45°/60°, 60°/30°, 60°/45°, and 60°/60° (axial/coronal) are recommended for preparing the femoral tunnel in PCLR.
Objective To evaluate the influencing factors that affect early pain after arthroscopic rotator cuff repair. MethodsA clinical data of 592 patients who met the selection criteria and underwent arthroscopic rotator cuff repair between June 2018 and October 2020 were retrospectively analyzed. There were 239 males and 353 females, with an average age of 58.1 years (range, 32-81 years). Before operation and at 3 days, 6 weeks, and 3 months after operation, the pain degree of patients was evaluated by visual analogue scale (VAS) score; and the patients were divided into no pain or mild pain group and moderate to severe pain group according to the postoperative VAS score. Preoperative and intraoperative related factors were included for univariate analysis, including age, gender, body mass index, preoperative VAS score, history of frozen shoulder, history of hypertension, history of diabetes, history of smoking, affected tendons (supraspinatus, infraspinatus, or subscapularis tendon injury), supraspinatus muscle atrophy, fatty infiltration, operation time, degree of rotator cuff tear, number of anchors, and whether to perform acromioplasty. The influencing factors of postoperative pain were screened; further logistic regression was used to conduct multivariate analysis to screen for risk factors. Results Moderate to severe pain occurred in 440 patients (74.3%) at 3 days after operation, 382 patients (66.2%) at 6 weeks, and 141 patients (23.8%) at 3 months. Multivariate analysis showed that the women, partial-thickness rotator cuff tear, and acromioplasty were risk factors for pain at 3 days after operation (P<0.05); the women, combined with fatty infiltration, partial-thickness rotator cuff tear, and acromioplasty were the risk factors at 6 weeks (P<0.05); and the women, combined with fatty infiltration, and partial-thickness rotator cuff tear were risk factors at 3 months (P<0.05). Conclusion Among patients undergoing arthroscopic rotator cuff repair, women, those with smaller rotator cuff tears, combined with fatty infiltration, and acromioplasty have more severe pain within 3 months after operation, and attention should be paid to postoperative analgesia in these patients management, providing an individualized approach to rehabilitation, and closer follow-up.