the present study will conduct to assess anterior knee pain and complications after medial UKA with or without patella denervation in medial compartment arthritis and severe lateral facet patellofemoral arthritis patients.

In this prospective cohort study, the investigators will conduct to compare the clinical result of 70 patients of unicompartment knee arthroplasty with and without patella denervation between April, 2018 and April, 2019 for the patients with osteoarthritis.

Inclusion Criteria:

• Patients who diagnose with medial osteoarthritis (OA) of the knee with an Alhback score of 2, 3 and 4 (Ahlback 1968) and with any Kujala score for pre-operative anterior knee pain.
• Older than 40 years of age.
• pain on the medial joint line.
• primary medial compartment osteoarthritis with a well preserved lateral compartment with competent cruciate ligaments with correctable intraarticular varus deformity.
• ROM flexion up to 110° under anesthesia.

Exclusion Criteria:

• Patients with fixed varus deformity > 15°
• Inflammatory arthritis
• Previous high tibial osteotomy or ACL reconstruction

unicompartment knee arthroplasty without patella denervation