Abstract
Objectives:
The menisci serve a critical role in knee biomechanics and joint preservation by absorbing axial load and distributing hoop stresses. The meniscal roots anchor the menisci to the tibial plateau and are essential for meniscal function, with posterior meniscal root tears leading to increased tibiofemoral contact pressures comparable to those following total meniscectomy. While meniscal root tears may occur concomitantly with ligamentous injuries in younger patients, they are often seen in a more degenerative setting in older individuals. If left untreated, the natural history of meniscal root injuries is poor with rapid progression of degenerative change that may necessitate total knee arthroplasty. Due to this understanding, treatment strategies have shifted away from meniscectomy and toward meniscal preservation via root repair. Nonetheless, it remains unclear which patients benefit most from meniscal root repair and over what time course these patients may see improvement.
The purpose of the present study was to assess the clinical characteristics of a cohort of patients undergoing primary meniscal root repair for isolated meniscal root injuries without concomitant ligamentous injury. Second, we sought to assess clinical, and patient reported outcome measures (PROMs) at various timepoints postoperatively.
Methods:
Patients undergoing primary meniscal root repair at a single tertiary academic center were prospectively enrolled in a registry database. Patients were excluded if they lacked a minimum of 6-month follow-up data, were undergoing a revision surgery, or sustained concomitant ligamentous procedures. Demographic and validated patient reported outcome measures (PROMs) including the Single Assessment Numeric Evaluation (SANE), the International Knee Documentation Committee (IKDC) Subjective Knee Form, and the Marx Activity Rating Scale (MARS) were collected at baseline, as well as at 6 months, 1- and 2-years postoperatively. Severity of radiographic degenerative change was assessed pre-operatively using the Kellgren-Lawrence (KL) grading scale, and cartilage change was assessed intra-operatively and described using the Outerbridge Classification. Patient and clinical characteristics were summarized using descriptive statistics; comparisons were conducted using t tests. All patients underwent an arthroscopic meniscal root repair using trans-tibial fixation and followed the same postoperative rehabilitation protocol.
Results:
Thirty-two patients met inclusion and exclusion criteria. The mean age at the time of surgery was 53.7 years (± 6.6 years) with females accounting for 26 patients (81.3%). The mean body mass index (BMI) was 30.5 kg/m2 (± 5.6 kg/m2) and the mean duration of pre-operative symptoms was 5.9 months (± 6.3 months). Thirty-one tears (96.9%) involved the medial meniscus while 1 patient (3.1%) suffered a lateral tear. Preoperative baseline radiographs demonstrated 5 patients (15.6%) with KL grade 0 degenerative changes, 20 patients (62.5%) with KL grade I, 4 patients (12.5%) with KL grade II, 1 patient (3.1%) with KL grade III, and 2 patients (6.3%) with KL grade IV. Intraoperatively, grade 3 or 4 Outerbridge scores were visualized within the patellofemoral compartment of 14 patients (43.8%), in the medial compartment for 20 patients (62.5%), and in the lateral compartment of 2 patients (6.3%).
Postoperatively, 77.4% of patients reached the minimal clinically important difference (MCID) of the IKDC by 6 months and 90.9% of patients reached this MCID by 1-year following surgery. IKDC scores improved significantly from baseline to 6 months postoperatively (p<0.001) as well as from 6 months to 1-year postoperatively (p=0.011), though no significant difference was observed between 1- and 2-years after surgery. Similarly, SANE scores demonstrated significant improvement from baseline to 6 months postoperatively (p<0.001) though no significant difference was noted from 6 months to 12 months or from 12 months to 24 months postoperatively. MARS scores decreased significantly from baseline to one year (p=0.002), though no significant change was noted from 1- to 2-years. No significant differences in PROMs were seen at any time point when patients were compared based on age, BMI or preoperative KL grade. Within our cohort, one patient later underwent ipsilateral total knee arthroplasty, one patient underwent subsequent meniscectomy, and one patient underwent an arthroscopic debridement and loose body removal.
Conclusions:
This study’s cohort of patients with isolated meniscal root repair without concomitant ligamentous injury was predominantly female, with a mean age above 50, and mean BMI over 30. Postoperative outcomes are favorable with no significant differences identified based on age, BMI, or pre-operative KL grade. Over three-quarters of patients achieve MCID for IKDC by 6 months postoperatively, and over 90% by one year. Most improvement in PROMs is achieved by one year following surgery, with fewer gains between one and two years. Additionally, meniscal root repair may be associated with a decline in MARS scores.
