Abstract
OBJECTIVE: To investigate the short-term effectiveness of high tibial osteotomy (HTO) for treatment of middle aged and older populations with varus knee combined with medial meniscus posterior root tear (MMPRT), and to evaluate the biomechanical changes in the knee joint after operation based on finite element analysis. METHODS: A retrospective analysis of clinical data was conducted on 35 patients (35 knees) admitted between June 2021 and October 2023, who met the inclusion criteria for varus knee combined with MMPRT. There were 17 males and 18 females with a mean age of 59.2 years (range, 48-65 years). Open wedge HTO was performed to correct the alignment in all patients. X-ray films and MRI were conducted before operation and at 3, 6, and 12 months after operation to assess changes in lower limb alignment and joint structure. And the femorotibial angle, medial proximal tibial angle (MPTA), posterior tibial slope angle (PTSA), weight-bearing line ratio (WBLR), as well as the Lysholm score, Hospital for Special Surgery (HSS) score, and visual analogue scale (VAS) score for pain were compared between pre- and post-operation. Finite element models were reconstructed based on knee CT data from a healthy volunteer to simulate changes in stress distribution at the knee joint before and after HTO, and to analyze postoperative mechanical improvement characteristics. RESULTS: All 35 patients underwent successful operations. Postoperatively, 3 cases of incisional fat liquefaction and 2 cases of mild superficial wound infection occurred; no complication such as deep vein thrombosis of the lower extremities, severe infection, or neurovascular injury was observed. All patients were followed up 12-14 months (mean, 13.0 months). Imaging reexamination revealed that all osteotomies had achieved radiographic union, with no complication such as osteotomy loss, significant collapse, or plate fracture. At 12 months after operation, the femorotibial angle, MPTA, WBLR, and PTSA were all significantly higher than preoperative levels ( P<0.05). Compared with preoperative values, the Lysholm score and HSS score gradually increased, while the VAS score decreased at 3, 6, and 12 months, with significant differences between different time points ( P<0.05). Finite element analysis showed that the stress distribution in the medial and lateral compartments of the knee joint tended toward equilibrium after HTO. Medial cartilage contact stress decreased by approximately 40% compared to preoperative levels, and stress concentration in the medial meniscus was significantly reduced. CONCLUSION: HTO can significantly alleviate knee pain in middle aged and older populations with varus knee combined with MMPRT, improve the distribution of knee joint forces, and promote the recovery of joint function.