Inclusion Criteria:  Age >18 years Primary osteoarthritis of the elbow with stiffness. Osteoarthritis was confirmed on CT-arthrography, by cartilage damage, osteophytes or local or global joint impingement. Ulnar neuropathy proven by electromyography without clinical symptoms Failure at least 6 months of conservative treatment Availability of medical information for >2 years of follow-up  Exclusion Criteria:  Severe skin contracture or wound problem that could affect the neurovascular structures or require flap surgery. Revision surgery Ulnar nerve pathology results in clinical symptom such as motion and feeling deficiency Other indication for elbow arthroscopy: synovial or inflammatory rheumatoid pathology, osteochondritis dissecan, acute infection, tumor or pure capsular stiffness. Inadequate or loss of follow-up elbow instability