Unicondylar- or Total Knee Replacement? Patient Satisfaction, Function and Muscle Mass

Unicondylar - or Total Knee Replacement in Medial Gonarthritis? A Randomized Study of Patient Related Outcome Measures, Function and Muscle Mass

Patients with medial gonarthritis are randomised to a unicompartmental or a total knee replacement.

Primary outcome: Thigh muscle cross sectional area and radiological attenuation measured by CT Secondary aims: functional tests, gait analysis, health related quality of life and patient related outcome.

Objective: The investigators aim with the present study was to compare patient related outcome measurements, knee function and muscle mass in patients operated with an UKR or a TKR for medial gonarthritis.

Hypothesis: The investigators hypothesize that a greater number of patients might benefit from a less invasive surgery in terms of increased quality of life, function and muscle mass.

Primary Outcome: Thigh muscle cross sectional area and radiological attenuation measured by CT.

Secondary outcomes: Functional tests (timed up and go, 30s sit and stand, forward reach, forward step down, 6 min walk and 40 m walk test), knee strength (Biodex isokinetic dynamometer) and patient reported pain on a visual analogue scale (VAS). A number of PROMs: Health related quality of life (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS) and Forgotten Joint Score (FJS) as well as 3D movement and gait analysis.

Inclusion criteria: Unilateral medial osteoarthritis of the knee (Kellgren 3b-4), aged 50 or above.

Exclusion criteria: Insufficient anterior cruciate ligament (ACL). Fixed varus deformity >10°, fixed flexion deformity >10°, flexion <100°. Previous high tibial osteotomy on the same side. Any neurological disease affecting strength or locomotion in any leg. Body mass index (BMI) >35. Rheumatoid disease. Symptomatic osteoarthritis of the contra lateral knee or any hip. Insufficient written or spoken Swedish.

Inclusion Criteria:

• medial gonarthritis, (Kellgren 3b-4)
• correctible varus deformity less than 10 degrees
• intact ACL
• proficient in written and spoken swedish

Exclusion Criteria:

• Valgus gonarthritis
• flexion deformity of 10 degrees
• knee flexion of less than 100 degrees
• previous high tibial osteotomy
• neuromuscular disorders of lower extremities
• symptomatic osteoarthritis of the contralateral knee or any hip.