The purpose of this study was to evaluate the degree of regeneration of cartilage after performing microfracture (MF) with high tibial osteotomy (HTO) after 2- year follow up and identify the factors influencing the regeneration of cartilage after the procedure. We also evaluated whether the regenerated cartilage status affects clinical outcomes.
A total of 81 cases that underwent second-look arthroscopy at the time of plate removal after MF and HTO with a minimum two-year follow-up were included. The cartilage regeneration status assessment was based on the ICRS Cartilage Injury Evaluation Package. The patients were divided into two groups according to femoral cartilage regeneration: group A (Normal group: ICRS grades I or II) and group B (Abnormal group: ICRS grades III or IV). Multivariable logistic regression analyses were calculated to identify independent factors that influence cartilage regeneration including patient factors (age, sex, BMI), radiologic factors (HKA angle, correction angle, and tibial slope) and articular factors (meniscus status, size of cartilage lesion, and presence of kissing lesions). We also compared differences in functional outcomes according to the Knee Society scores and the WOMAC score at the last follow-up between the two groups.
On the femoral side, grade I cartilage regeneration was found in seven (8.6%), grade II in 19 (23.5%), grade III in 26 (32.1%), and grade IV in 29 cases (35.8%), resulting in 26 (32.1%) patients belonging to normal group (group A) and 55 (67.9%) to the abnormal group (group B). Among factors, the size of the cartilage lesion (P=.011) and the presence of kissing lesions (P=.027) significantly affected cartilage regeneration. There were no statistically significant differences between group A and group B in terms of KSS and WOMAC scores.
A large cartilage defect and the presence of kissing lesions are associated with poor cartilage regeneration after combined MF and HTO surgery. However, the quality of regenerated cartilage does not affect functional outcomes in patients with MF and HTO.
Keywords: High tibial osteotomy, Microfracture, Second-look arthroscopy, Cartilage regeneration