A preliminary report of patellofemoral arthroplasty in isolated patellofemoral arthritis

Background Isolated patellofemoral osteoarthritis is not uncommon.Surgical treatment of isolated patellofemoralarthritis remains controversial and poses a challenging treatment dilemma.The present study aimed to evaluate theshort-term results of patellofemoral arthroplasty for patients with isolated patellofemoral osteoarthritis.Methods We analyzed 11 patellofemoral arthroplasties performed from March 2006 to September 2009 in 11 patientswith isolated patellofemoral arthritis.The patients comprised 2 males and 9 females with an average age of 53.7 years(range,46-74 years).Standard weightbearing radiographs were taken in the anteroposterior,lateral,and 45° axial views.The knee pain and functional status were evaluated by the Western Ontario and McMaster Universities OsteoarthritisIndex (WOMAC) scales and American Knee Society (AKS) scores.For comparison,23 total knee arthroplasties in 23patients with primary tibiofemoral osteoarthritis were matched according to age,gender,bilaterality and body mass index.The duration of follow-up was 23.7 months (range,12-47 months).Results The majority of the 11 patients experienced improvement in their patellofemoral symptoms after patellofemoralarthroplasty.The WOMAC scores improved considerably by 7.4 points with respect to pain and by 5.2 points with respectto function.The AKS scores also improved considerably by 23.9 points with respect to pain and 44.3 points with respectto function.Although the clinical outcomes after patellofemoral arthroplasty were not better than those after total kneearthroplasty,patellofemoral arthroplasty exhibited advantages in the shorter operation time,lower blood loss andincreased postoperative range of motion.At the latest follow-up,there was no clinical or radiographic evidence ofpatellofemoral maltracking,loosening or wear.Conclusions On the basis of our experience in this relatively small series of patients with a short-term follow-up,patellofemoral arthroplasty is an effective treatment alternative to total knee arthroplasty in isolated patellofemoralarthritis.MRI and arthroscopy may contribute to define those patients with isolated patellofemoral degeneration.