1. Patient selection
This study was approved by the medical research ethics committee of our institutional. A total of 64 patients with medial meniscus posterior root tears received treatment of posterior meniscus root attachment point through the tibial tunnel between June 2018 and April 2019 were included in this study, and patients were divided into 2 groups (transtibial pull-out technique group: 35 cases; gracilis autograft with suture reinforcement technique group: 29 cases) according to the different repair methods for the meniscus posterior root tear.
Diagnosis of patients with medial meniscus posterior root tears primarily relies on clinical evidence and knee magnetic resonance imaging (MRI), all patients underwent arthroscopic reconstruction of the posterior root of the meniscus attachment point with a minimum 2-year follow-up. Indications for surgery included medial meniscus posterior root tears and no changes or 1–2 stages osteoarthritis of the knee joint. Patients undergoing surgery for other indications (cartilage resurfacing, osteotomy or ligament reconstruction), previous surgery of the same knee (previous tibia or femur fracture), complex root tears, concomitant ACL injury or other associated knee joint lesions were excluded from the study. As medial meniscus posterior root tears occurred frequently associated with other meniscus concomitant injury, so meniscus concomitant injury was not excluded from the study.
2. Data collection
The following parameters were recorded: age, gender, comorbidities, stages OA of the knee joint evaluated according to Kellgren and Lawrence, treatment for medial meniscus posterior root tears, hospitalization time, side of injury, preoperation and postoperative visual analogue scale (VAS), Lysholm score and International Knee Documentation Committee (IKDC) score of the affected knee, complications, and healing status of the repaired meniscus at the final follow-up.
3. Surgical techniques
3.1 pullout repair techniques
Arthroscopic evaluation and treatment of the medial meniscus posterior root tear and other intraarticular lesions with patients under spinal anesthesia. A limited refreshed was applied to the torn edge of the meniscus with a motorized shaver, and a guide pin drilled from a small incision over the anterior proximal tibia and advanced to the posterior horn root of knee under the special guide system (Smith & Nephew) assisted. Then, the suture shuttle was used to place a No. 0 fiber wire suture (Smith & Nephew) through the posterior meniscus and shuttled into the tibial tunnel and the meniscus root down into the posterior horn root attachment under arthroscopic visualization control. The fiber wire sutures were tightened to button to ensure appropriate position and tension of the construct.
3.2 Gracilis autograft with suture reinforcement technique
Arthroscopic evaluation and treatment of the medial meniscus posterior root tear and other intraarticular lesions with patients under spinal anesthesia. A limited refreshed was applied to the torn edge of the meniscus with a motorized shaver, and a guide pin drilled from a small incision over the anterior proximal tibia and advanced to the posterior horn root knee joint under the special guide system (Smith & Nephew) assisted. The suture shuttle was used to place a No. 0 fiber wire suture (Smith & Nephew) through the posterior meniscus, then, the soft tissue tunnel is dilated with multiple passes of No. 0 fiber wire followed by the gracilis tendon passes through the medial meniscus posterior root and shuttled into the tibial tunnel. The tails of the gracilis tendon were fixed with an anchor to the tibial, and arthroscopic visualization is used to maintain the appropriate position and tension of the graft.
4. Postoperative management
Passive knee flexion and quadricep-strengthening exercises were started on the second day. Moreover, patients were allowed to walk non-weight-bearing with two crutches for six weeks, and weight bearing was progressed as tolerated starting at 6 weeks postoperatively, no heavy strenuous activities were allowed for the first 12 weeks.
5. Outcome assessment
The outcome was evaluated by 2 orthopedics surgeons, and imaging and clinical examinations were performed at directly postoperative, 1 month, 3 months, 6 months, 12 months, and 24 months, and knee functional assessment was performed according to the Lysholm score, IKDC score and VAS score.
At the final follow-up, radiologic outcomes of the repaired meniscus healing status were assessed by orthopedic surgeons and radiologist using knee MRI according to the criteria of previous studies [9-11].
6. Statistical analysis
Quantitative variables were presented as mean value ± standard deviation (SD), and the two groups were compared using the Student’s t-test. Count variables were expressed as numbers and percentages and were assessed by the Chi-square test. Statistical significance was set as P value less than 0.05. All analysis was performed by IBM SPSS Version 22 (SPSS Inc. Chicago IL).