Hemi-tibial Plateau Osteotomy Combined With Arthroscopic Repair for Medial Meniscus Posterior Root Tears in Varus Knees

This is a single-center clinical trial started by the study team. The goal is to compare two surgeries for people who have a varus knee alignment and a tear at the back attachment of the medial meniscus. Researchers want to learn whether the newer bone-cut procedure with arthroscopic meniscus repair works no worse than the standard bone-cut procedure with arthroscopic meniscus repair. Researchers will also track safety and hospital-related costs. Main questions the study aims to answer: * At 12 months after surgery, is the improvement in knee function no worse in the newer-surgery group than in the standard-surgery group? The study will treat the newer surgery as \"no worse\" if its average improvement is not more than eight points lower on the Lysholm knee function score. * Do the two groups differ in pain relief, imaging findings, meniscus healing, complications, and hospital stay and costs? The study plans to enroll about 20 participants at Sun Yat-sen University Eighth Affiliated Hospital (Shenzhen Futian). Participants will be assigned by chance, like drawing lots, in a one-to-one ratio. This is an open-label study, meaning participants and surgeons will know which surgery is used. Study groups: * Experimental group: hemi-tibial plateau osteotomy plus arthroscopic meniscus repair. * Control group: high tibial osteotomy plus arthroscopic meniscus repair. Who may join: * Age 35 to 65 years, with no restriction on sex; * Diagnosed with a medial meniscus posterior root tear; * Presence of varus knee deformity; * Imaging findings support the diagnosis (e.g., knee MRI); * Failure of conservative treatment: no meaningful improvement after more than 1 month of non-surgical management (e.g., rest, medication, or physical therapy); * Varus alignment angle less than 10 degrees; * The deformity is predominantly tibial in origin; * Knee radiographs do not show the most severe osteoarthritis (Kellgren-Lawrence grade other than IV). Who cannot join: * A knee that is chronically \"locked,\" meaning it cannot bend or straighten normally. * The most severe level of knee arthritis on knee X-ray. * Severe arthritis in the hip or ankle that could affect knee function testing. * Inflammatory or infectious conditions that can affect the knee, or abnormal inflammation blood tests that make participation unsafe. * Knee instability or poorly functioning prior ligament reconstruction, based on the study doctor\'s judgment. * Any prior surgery on the target knee, or on other joints of the same-side lower limb. * Serious heart, liver, or kidney disease, cancer, bleeding disorders, immune deficiency, or severe mental health conditions that make participation unsafe. * Body mass index of 30 or higher. * Pregnancy or breastfeeding, or not willing to use birth control during the study. * Participation in another clinical study within the past 3 months (except registry studies). * Any other reason the study doctor believes makes participation unsafe or not appropriate. What participants will do: * Complete screening and baseline assessments within about 30 days before surgery and sign informed consent. * Receive the assigned surgery during the hospital stay. * Return for follow-up visits at 3 months, 6 months, and 12 months after surgery. * Complete knee function and symptom questionnaires and rate pain at each follow-up visit. * Have standing knee X-rays and full-length leg X-rays at 3, 6, and 12 months. * Have an MRI of the operated knee at 3, 6, and 12 months to assess meniscus healing and meniscus extrusion. Outcomes: * Primary outcome: change from baseline to 12 months in the Lysholm knee function score. * Secondary outcomes: changes in the Lysholm score at 3 and 6 months; changes in the WOMAC knee arthritis symptom score at 3, 6, and 12 months; changes in pain rating on a standard pain scale at 3, 6, and 12 months; imaging measures and bone healing on X-rays; meniscus healing and extrusion on MRI; surgery time and blood loss; complications during and after surgery; length of hospital stay and hospital costs; and quality of life utility value from a standard health questionnaire.