Residual knee pain and functional outcome following total knee arthroplasty in osteoarthritic patients.

PURPOSE: Total knee arthroplasty (TKA) is a successful and safe elective operation in managing patients with severe osteoarthritis of the knee. However, the presence of residual knee pain (RKP) post-TKA can adversely affect patient satisfaction and functional outcome. Hence, the aim of this paper is to identify the incidence, progression of knee pain, functional outcome post-TKA and possible predictive factors for the development of RKP post-TKA.
METHODS: A retrospective review of 357 patients was conducted with a minimum follow-up period of 2 years. Predictive factors reviewed include the patients' demographics, co-morbidities, type of implants and patellar management. For functional outcome, the patient's Knee Society Score (KSS) and Western Ontario and McMaster Universities Index of Osteoarthritis scores were analysed. To determine presence and severity of RKP, the sub-score for pain in the KSS was utilised.
RESULTS: In total, 31.1 and 28.9% of the patients were found to have RKP at 1 and 2 years, respectively, though their functional outcome scores continued improving from 1 year. Ischaemic heart disease (IHD) patients were more likely to have RKP and poorer functional outcome at 1 year. Males and patients with posterior-stabilised implants were found to have better functional outcome at 1 and 2 years, respectively.
CONCLUSIONS: Almost a third of the patients continued to have RKP at 2 years post-TKA, with factors such as gender, presence of IHD and implant type significantly associated with the development of RKP and/or poorer functional outcome scores. By recognising the incidence and predictive factors for RKP, physicians will be able to better manage their patients' expectations and optimise their pre-morbid status pre-operatively. LEVEL OF EVIDENCE: III.