Inferior outcomes of total knee replacement in early radiological stages of osteoarthritis

Total knee replacement (TKR) for osteoarthritis (OA) is a common and successful operation; the severity of radiographic changes plays a key role as to when it should be performed. This study investigates whether an early radiological grade of OA has an adverse effect on the outcome of TKR in patients with arthroscopically confirmed OA.

Between January 2006 and January 2011 data was collected prospectively on all patients undergoing a primary TKR for OA. We included all patients with a Kellgren–Lawrence score of two or less on their pre-operative radiograph who had had an arthroscopy to confirm significant OA. Our primary outcomes were the Oxford Knee Score (OKS) and a satisfaction rating.

Over the study period 1708 primary TKRs were performed in 1381 patients. We identified 44 TKRs in 43 patients with a Kellgren–Lawrence score of two or less on their pre-operative radiograph. In this group the mean age was 63 years, 66% were female and the mean BMI was 31.7 kg/m ². At a mean follow-up of 37 months the mean OKS was only 30 points compared to 36 in all TKRs performed over the same period ( p = 0.0004). Only 68% were either satisfied or very satisfied. Eight knees (18%) underwent further surgery, three (6.8%) of which were revision procedures, compared to a revision rate of 1.6% in all patients.

The outcomes of TKR in patients with early radiological changes of OA are inferior to those with significant radiological changes and should be performed with caution.

Level IV case-series.