Evaluate the results of management of patients with patellofemoral and medial compartment knee osteoarthritis with open wedge high tibial osteotomy with or without arthroscopic partial lateral patellar facetectomy

Patients will undergo OWHTO in a standardized fashion by the same team of surgeons.

They will be randomly divided into 2 groups either OWHTO with arthroscopic partial lateral patellar facetectomy or OWHTO without arthroscopic partial lateral patellar facetectomy in a 1:1 ratio.

The patient will be placed supine on the operating table. After the induction of spinal anesthesia, a knee examination will be performed to evaluate for any concurrent pathology and to assess for knee range of motion, patellar mobility, position, instability, and patellar crepitus during knee flexion. A well-padded thigh tourniquet will be placed on the upper thigh of the operative leg to maintain a bloodless field. The surgical leg will be prepared and draped in a sterile fashion, the leg exsanguinated, and the tourniquet inflated. an arthroscope will be inserted through the anteromedial, anterolateral and suprapatellar portals to access the entire perimeter of the patella. The joint will be insufflated with normal saline and visualized with a 30 degree arthroscope. Diagnostic arthroscopy will be performed in all cases to assess PF articular cartilage degeneration, classify the cartilage defect using the Outterbridge classification , assess the lateral compartment and exclude any other pathology. An arthroscopic shaver will be inserted into the knee and any notable adhesions will be removed. Any meniscal, cartilage, or ligamentous injury may be treated first. The knee will be taken throughout a range of motion to directly visualize the impingement of the lateral patellar facet against the trochlea. Next, a radiofrequency probe will be used to outline the area to be resected along the lateral patellar facet While maintaining the knee at 20 degree of flexion, a 5.5-mm burr is introduced, and under arthroscopic visualization, the lateral patellar osteophyte and the overhanging portion of the lateral facet will be carefully resected. Once the bony resection is complete, the knee is dynamically re-evaluated (through flexion and extension) for residual impingement and to assess for improvements in patellar mobility. Patellar tracking will be assessed to verify that there is no catching in flexion and that patellar mobility is improved.

After arthroscopic partial lateral patellar facetectomy, all patients will undergo OWHTO. All procedures will be performed based on the technique recommended by the AO international knee expert group. Biplanar osteotomy, which comprises osteotomies in the axial and frontal planes, was performed in all cases. Ascending frontal osteotomy, leaving the tibial tuberosity on the distal fragment, was also performed. All osteotomies will be performed without the use of additional bone grafts, and the opening of the osteotomy will be maintained with a Tomofix plate (Orthomed-E Co., Egypt). Wound closure was performed in layers.

Inclusion Criteria:

1. Age 35-60years
2. Mild to moderate TFOA (G I-II-III) Kellgren-Lawrence (KL) scale (16)
3. Anterior knee pain (PFOA)
4. No involvement of the lateral compartment
5. range of motion of at least 120° flexion
6. Body mass index (BMI) <30kg/m2
7. varus angle degree <10°

Exclusion Criteria:

1. advanced case of TFOA (G VI KL scale), which requires total knee replacement.
2. flexion deformity ≥15°
3. inflammatory disease (such as rheumatoid arthritis).