Complications of Patella in Total Knee Arthroplasty (TKA)

Background and Methods: Postoperative complications may impair the outcome of total knee arthroplasty (TKA). Patellar instability is a major cause of postoperative pain and functional limitation for which revision surgery may be necessary [1]. It may occur after TKA with or without patellar resurfacing. RESULTS AND CONCLUSIONS: Subluxation is more common than dislocation; the incidence of symptomatic instability leading to revision is low (0.5 to 0.8%) [2, 3]. In a multicentre study of low contact stress mobile bearing TKAs, only 6 of 259 revisions were associated with patellar instability, which accounted for a revision rate of 0.1% after a mean follow-up duration of 5.7 years [4]. A revision rate of 12% was reported secondary to complications of the extensor mechanism [5]. The aetiology of patellofemoral instability can be related to (1) the surgical technique and component positioning, (2) extensor mechanism imbalance, and (3) other causes.