A Cohort Study Predicts Better Functional Outcomes and Equivalent Patient Satisfaction Following UKR Compared with TKR.

BACKGROUND: Total knee replacement (TKR) is considered the gold standard treatment for advanced osteoarthritis of the knee (Choong and Dowsey, Int J Rheum Dis 14:167-74, 2011; Satku, Singapore Med J 44:554-556, 2003). Unicompartmental disease can be treated with unicompartmental knee replacement (UKR) or TKR. Some surgeons prefer the proven track record of TKR, while others prefer the more normal joint kinematics, enhanced proprioception and range of movement achieved with UKR (Hopper and Leach, Knee Surg Sports Traumatol Arthrosc 16:973-9, 2008; Satku, Singapore Med J 44:554-556, 2003). However, there is reported low satisfaction amongst younger patients undergoing UKR (Robertson et al., Acta Orthop Scand 71:262-7, 2000).

QUESTIONS/PURPOSES: The purpose of this study is to compare patient-reported outcomes, satisfaction and perception of knee normality in age-matched groups of postoperative TKR and UKR patients aiming to answer the following question: Does UKR have lower patient satisfaction than TKR in younger patients?

METHODS: Sixty-eight patients were recruited from the care of a single surgeon. Patients with isolated medial compartment osteoarthritis, stable ACL and less than grade 3 lateral patellar disease underwent UKR. All other patients underwent TKR. Patients were assessed with validated knee scores. Satisfaction was assessed with a visual analogue scale.

RESULTS: There was no statistical difference in patient satisfaction or perception of knee normality scores between the two groups, despite better functional scores including WOMAC, SF-36 and Oxford knee in the UKR group.

CONCLUSION: Patient satisfaction is similar amongst TKR and UKR patients despite better functional outcome in terms of recreation and sport with UKR. This may reflect higher preoperative expectations in patients undergoing UKR. Further work is needed to assess this.