The purpose of this study was to analyse the results of total knee arthroplasty (TKA) in stiff knees (flexion ≤90° and/or flexion contracture ≥20°). Our hypothesis was that despite having poorer results than those obtained in a “standard” population and a high rate of complications, TKA was a satisfactory treatment in patients with osteoarthritis of the knee associated with significant stiffness.

Three hundred and four consecutive primary HLS TKAs (Tornier), whose data were prospectively collected between October 1987 and October 2012, were retrospectively analysed at a mean of 60 months (range, 12–239) postoperatively. Two groups, those with a “flexion contracture” and those with a “flexion deficit”, were assessed for postoperative range of motion (as integrated to the Knee Society score [KSS]), physical activity level and patient satisfaction.

At the latest follow-up, range of motion was significantly improved, as was the KSS. Ninety-four percent of patients were satisfied or very satisfied, and activity levels were increased after surgery. The complication rate, however, was high in patients with a preoperative flexion deficit (17 %). Pain and residual stiffness were the most common complications.

TKA provides satisfactory results in patients with knee osteoarthritis associated with significant pre-operative stiffness. The surgical plan should be adapted to anticipate complications, which are particularly frequent in the presence of a flexion deficit.