Complex intra-articular fractures of the proximal tibia are difficult to treat, especially in the elderly osteoporotic patient. Pre-existing osteoarthritis, cartilage damage during trauma, suboptimal reduction and fixation due to poor bone stock and/or secondary displacement frequently lead to poor outcome. After osteosynthesis rehabilitation is cumbersome as patients have been non-weight bearing for long periods of time and secondary total knee arthroplasty can be challenging. For these reasons, we investigated the possibility to perform a total knee arthroplasty with or without adjuvant osteosynthesis as a primary treatment in elderly and/or osteoarthritic patients with complex tibial plateau fractures. Between 2002 and 2009, 12 patients (mean age: 73 years (58-81)) with an AO-41 fracture type B1 (1), B3 (8) and C3 (3) were treated with a primary total knee arthroplasty within three weeks from their trauma. Most patients (7/12) were allowed early full-weight bearing. One patient died due to an unrelated cause; the remaining eleven were reviewed at a mean follow-up period of 31 months (5 w-81 m). At final follow-up the median knee score was 78 (50-100) and the function score 58 (0-100): 7/11 patients had an excellent result, while 1/11 had a fair and 3/11 a poor result. Fair and poor results were mostly related to pre-existing poor general condition and/or concomitant disease. Most patients were satisfied and only minor short- and long-term complications were noted. There was no need for revision surgery. Our limited series of well-selected elderly and/or osteoarthritic patients with a complex tibial plateau fracture treated with primary total knee arthroplasty yielded encouraging results.