Arthroscopic pie-crusting release of the posteromedial c omplex of the knee for surgical treatment of medial meniscus injury

Background: The posteromedial complex (PMC), including the posterior part of the MCL and the posterior oblique ligament (POL), has a restrictive effect on the opening of the posteromedial gap of the knee in the half-extension position. We evaluated the radiological and clinical results of pie-crusting release of the PMC for arthroscopic meniscal surgery in tight knees.Methods: Sixty patients with posterior injury of the medial meniscus were reviewed. All patients accepted arthroscopic pie-crusting release of the PMC. Fourty patients accepted meniscoplasty, and 20 patients accepted meniscal suturing. To evaluate the arthroscopic opening of the medial gap in 20° half-extension under 11-kg valgus stress, the width of the medial space before and after release were measured. During follow-up, the medial stability was evaluated by radiographic measurements of the joint space width (JSW). MRI was conducted to evaluate healing of the MCL and meniscus. Knee functions were evaluated using VAS, Lysholm, IKDC and Tegner scoring systems.Results: In all patients, meniscus operations were performed without iatrogenic cartilage injury. After PMC release, the arthroscopic width of the medial space was 5.7 ± 0.5 mm, larger than that before release (2.5 ± 0.5 mm, p < 0.01). The follow-up time was 21.93 ± 7.04 months, there was no residual valgus laxity of the knee. The radiographic JSW was 5.97 ± 0.8 mm preoperatively, 9.2 ± 1.1 mm in the 1st week postoperatively, and 6.1 ± 0.9 mm by the 3rd postoperative month, showing no differences between preoperative and 3 months postoperative measurement (p > 0.05). For sutured meniscus, MRI showed healing in 15 patients while five had two-grade abnormal signals. VAS, Lysholm, IKDC and Tegner scores were 1.80 ± 0.51, 80.08 ± 3.74, 82.17 ± 4.64 and 5.48 ± 0.59, respectively, showing significant differences compared with the preoperative It can be seen from this analysis that the posterior part of the MCL and the POL are the main tissue structures which restrict the opening of the posteromedial space in the half-extension position under knee valgus. We performed percutaneous multi-point acupuncture for the posterior part of the MCL, POL and articular capsule using an 18-G needle at the posterior 1/3 region of the knee joint, and satisfactory posterior space exposure was obtained under valgus stress. posteromedial space of the knee joint. the of of the knee after One imaging study in the literature which reported changes in the medial gap after MCL release found that the release caused a partial tear of the MCL, and the medial space was 2 mm, 0.9 mm and 0.1 mm at 1 week, 1 month and 3 months after operation, respectively Another study showed that the MCL injury was rated grade I (< 5 mm opening on the medial side) in the valgus position with 20° flexion immediately after operation but negative at 6 weeks after operation, and there was no subjective feeling of medial instability of the knee during follow-up A similar result was also found in our study; the patients had no subjective or objective medial instability of the knee joint at 3 months after operation and the joint space width from X-ray radiographs was 6.13 ± 0.89 mm, showing no significant difference compared with preoperative 5.97 ± 0.89 mm, indicating healing of the injured PMC. The main factors related to knee stability after pie-crusting release of the PMC were as follows: POL part The width medial space which only maintained of the posteromedial stable within the range of grade I Patients wear a for at least 4 weeks after operation, which ensured the healing of the sutured meniscus and the released posteromedial stable structure, thus avoiding the of iatrogenic knee instability.