Osteotomies are among the oldest orthopedic treatments, in use for over 2000 years and still commonly employed. The basic principle involves making a bone cut to allow the realignment of the limb segment affected by deformity. Today, new knowledge and technologies, understanding of bone healing mechanisms, and the introduction of new fixation methods have made osteotomies one of the preferred treatments for early knee arthritis. They serve as an alternative to joint prosthesis implantation in young patients with medium to high functional demand.

Medial knee osteoarthritis is a pathology increasingly prevalent in today's population. The resulting varus deformity leads to a shift in the load axis on the medial tibial plateau. Osteotomy in this context becomes a therapeutic tool capable of restoring the correct mechanical axis of the lower limb and delaying or avoiding the progression of arthritis, thus avoiding the need for joint replacement.

The two most commonly used techniques are the Closing Wedge Lateral High Tibial Osteotomy (LCW-HTO) and the Opening Wedge Medial High Tibial Osteotomy (MOW-HTO), which are high tibial osteotomies in closure with a wedge removal and in opening with a wedge insertion, respectively.

The medium to long-term effects of this procedure, in terms of survival and modification of the tibial slope, have been extensively studied, as evidenced by the extensive literature on the subject. However, the effect of this intervention, in its two variants, on the progression of femoro-patellar arthritis and the height of the patella remains poorly investigated to date.

Inclusion Criteria:

1. Diagnosis of medial unicompartmental knee osteoarthritis (Outerbridge III-IV)
2. Follow-up > 60 months
3. Completeness of clinical and radiographic documentation.
4. Previous valgus osteotomy procedure (MOW-HTO or LCW-HTO)
5. Age <65 years

Exclusion Criteria:

1. Patients with previous injuries affecting the involved lower limb.
2. Patients with prior traumatic, septic, and rheumatoid arthritis.
3. Patients with previous alterations of the patellofemoral joint.
4. Patients with knee ligament injuries.
5. Patients with confirmed neuromuscular disorders or psychomotor disturbances.
6. Patients with congenital generalized hypermobility syndrome.
7. Patients with severe pathologies in other organs or systems limiting activities of daily living (ADL).
8. Patients who refuse to participate in the study.