Poster 239: Advanced Patellofemoral Chondromalacia Does Not Affect Outcomes After Meniscal Root Repair

OBJECTIVES: Meniscal root tears have been shown to accelerate cartilage breakdown and increase the risk of total knee arthroplasty (TKA) if left unaddressed. Unfortunately, many patients with meniscal root tears already have associated chondromalacia which can impact surgical outcomes. The presence of advanced chondromalacia in the medial or lateral compartmentsof the knee is a known contraindication to performing meniscal root repair; however, the effect of advanced patellofemoral chondromalacia on meniscal root outcomes is not known. The purpose of this study was to compare the outcomes of meniscal root repair in patients with and without advanced patellofemoral chondromalacia (PFC). METHODS: A retrospective review of prospectively collected data of patients undergoing meniscal root repair by a single surgeon was conducted between January 2016 and December 2019. Patients were included if they had undergone an isolated posterior medial or lateral meniscal root repair. The meniscal root repair was performed using a transtibial suture technique. Patients were placed into one of two groups depending on the amount of patellofemoral chondromalacia present at the time of surgery. Patients with Outerbridge grade 0-2 were placed in the Minimal Patellofemoral Chondromalacia (MPFC) Group. Patients with Outerbridge 3-4 changes found the time of surgery were placed in the Patellofemoral Chondromalacia (PFC) Group. Patients with Outerbridge 3-4 changes found in the medial or lateral compartment were excluded from the study. Lysholm Knee Scoring Scale and the International Knee Documentation (IKDC) Subjective Knee Form were collected preoperatively, 6,12 and 24 months after surgery. Clinical outcomes followed included recurrent meniscal tear, conversion to total knee arthroplasty, knee arthrofibrosis requiring manipulation under anesthesia/lysis of adhesions and infection. PASS and MCID were determined using data on meniscal repairs in other literature. Continuous data was compared using two-tailed student-T test while categorical data was compared utilizing chi-square testing. RESULTS: A total of 27 patients made up the PFC group and 54 in the MPFC group. There was no difference between the groups with regards to age, sex, BMI or laterality of the procedure. The PFC group had 26 medial and 1 lateral meniscal root repairs. The MPFC group had 51 medial and 3 lateral repairs. The average Outerbridge score of the patella for the PFC group was 3.2 compared to 1.8 in the MPFC group (p<.001). The Outerbridge score for the trochlea in each group was 3.4 vs. 1.6 for the PFC and MPFC groups respectively (p<.001). No difference was identified between the Outerbridge score for the medial compartment for the PFC and MPFC groups (1.48 vs 1.46 respectively) or the lateral compartments (0.48 vs. 0.61 respectively). Lysholm and IKDC scores rose significantly over the pre- operative value at all time points in the study for both groups. No difference was seen between the two groups for the Lysholm or IKDC scores at any timepoint during study. PASS rates for IKDC between the two groups were similar with 6,12 and 24-month PASS rates being 66.7%, 87.5% and 81.4% respectively for the PFC group and 62.9%, 77.8% and 85.2% for the MPFC group. There was also no difference between the groups with regards to the percentage of patients reaching MCID for IKDC. The PFC group showed the percentage of patients reaching MCID to be 81.5%, 100% and 92.6% at the 6,12, and 24 month time points respectively while the MPFC group showed the percentage of patients reaching MCID to be 75.9%, 88.9% and 94.4% at the 6,12 and 24 month postoperative time points respectively. There was 1 (3.7%) recurrent tear in the PFC group and 3 (5.6%) in the MPFC group (p=.72). One patient (3.7%) in the PFC and none of the MPFC group were converted to TKA by the 2-year follow up (p=.15). Each group had 1 patient develop arthrofibrosis requiring MUA/LOA. There were no infections in the PFC group and one in the MPFC group which was a superficial wound infection that resolved after a course of oral antibiotics. CONCLUSIONS: In our series, the presence of advanced patellofemoral chondromalacia did not lead to inferior short-term outcomes in patients undergoing meniscal root repair compared to patients without patellofemoral chondromalacia. IKDC and Lysholm scores were similar between the PFC and MPFC group at all time points while scores for both groups were significantly higher than preoperative levels at all time points. The ability to reach MCID and PASS for IKDC was not significantly different between the two groups. In addition, there was not a significant difference between the two groups in the number of recurrent tears, conversion to total knee arthroplasty or complications identified. Our results show meniscal root repair can be performed in patients with severe patellofemoral chondromalacia with similar results as patients undergoing root repair without severe patellofemoral chondromalacia. Patellofemoral chondromalacia should not be considered a contraindication to meniscal root repair.