Isolated patellofemoral arthroplasty is discussed controversially. The aim of this nation-wide survey in Germany and review of the literature was to determine the current status of patellofemoral arthroplasty.
A standardised questionnaire was sent to 744 German departments of orthopaedic surgery, traumatology and general surgery. In the first part, surgeons were asked general questions about their department size, case numbers of knee arthroplasties per year and non-endoprosthetic treatment of isolated patellofemoral disorders. If patellofemoral arthroplasty was conducted, parameters concerning age, gender, duration of complaints, indication for surgery, surgical approach, type of endoprosthesis used, additional surgical treatments and failures were evaluated in the second part. Furthermore we asked for the reasons if no isolated patellofemoral arthroplasty was performed. A systematic review of the literature was done including studies published until October 2007. The main inclusion criterion was the presentation of results after the implantation of a patellofemoral prosthesis for isolated patellofemoral osteoarthritis.
A total of 225 analysable questionnaires were returned. Of 53,420 knee arthroplasties performed per year, only 195 (0.37 %) were isolated patellofemoral arthroplasties. The majority of patients (91 %) were between 40 and 80 years old. The aetiology of isolated patellofemoral osteoarthritis was believed to be idiopathic in 41 % and traumatic in 8 %. Patellofemoral dysplasia was held to be responsible in 47 % and patellofemoral instability in 4 % of the cases. The main reason for failure and surgical revision was ongoing tibiofemoral osteoarthritis of the affected knee. Negative attitude and disbelief towards the success of isolated patellofemoral arthroplasty were stated by the majority (62 %) of non-users. A lack of appropriate indications was reported by 22 % and lacking know-how by 16 %. We analysed 12 studies (459 implantations; 390 patients) in the literature review. The treatment was considered successful in 67.8 % of cases. The overall revision rate was 30.3 %. The highest failure rates were in patients with progression of tibiofemoral osteoarthritis or malalignment.
Isolated patellofemoral arthroplasty has only low significance among surgeons performing knee arthroplasty in Germany. The majority of surgeons do not believe in the success of the procedure. Almost one third of published cases in the literature needed to be revised.