Aim To investigate whether the current, generally accepted practice of orthopaedic surgical skills training can raise the performance of supervised residents to levels equal to those of experienced orthopaedic surgeons when it comes to clinical outcomes or implant position after total knee arthroplasty.

Methods In a retrospective analysis of primary total knee arthroplasty outcomes (minimum follow-up of 12 months) procedures were split into two groups: supervised orthopaedic residents as first surgeon (group R), and experienced senior orthopaedic surgeons as first surgeon (group S). Outcome data that were compared 1 year postoperatively were operation times, complications, revisions, Knee Society Scores (KSS) and radiological implant positions.

Results Of 642 included procedures, 220 were assigned to group R and 422 to group S. No statistically significant differences between the two groups were found in patient demographics. Operation time differed significantly (group R: 81.3 min vs. group S: 71.3 min (p = 0.000)). No statistically significant differences were found for complications (p = 0.659), revision rate (p = 0.722), femoral angle (p = 0.871), tibial angle (p = 0.804), femoral slope (p = 0.779), tibial slope (p = 0.765) and KSS (p = 0.148).

Discussion and conclusion Supervised residents needed 10 minutes extra operation time, but they provided the same quality of care in primary total knee arthroplasty as experienced orthopaedic surgeons concerning complication rates, revisions, implant position on radiographs and KSS.