The effect of gender on outcome of unicompartmental knee arthroplasty S. Lustig a,b, ⁎, N. Barba a , R.A. Magnussen a , E. Servien a,b , G. Demey a , P. Neyret a,b a Service de chirurgie orthopédique, Centre Albert Trillat, Hôpital de la Croix Rousse, 103, Grand Rue de la Croix Rousse, 69004 Caluire, Lyon, France b Université Lyon 1, F-69003, Institut National de Recherche sur les Transports et la Sécurité, Bron, F-69675, Laboratoire de Biomécanique et Mécanique des Chocs, UMR_T 9406, France abstract article info Article history: Received 10 June 2010 Received in revised form 21 February 2011 Accepted 1 March 2011 Keywords: Unicompartmental knee arthroplasty (UKA) Gender No report has specifically addressed the question of the influence of gender on outcome following unicompartmental knee arthroplasty (UKA). To clarify this issue, we studied two groups of 40 patients of each gender, matched by pre-operative clinical and radiological presentation, and with post-operative follow up of at least 2 years. The mean age at operation was 71 years and the mean follow-up was 5.9 years. In both groups, IKS score improved significantly, but without difference based on gender. No difference was found between groups in terms of range of motion, alignment, or radiologic progression of arthritis. These results suggest that when utilizing specific patient selection criteria, gender does not influence outcome following UKA. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The influence of gender on outcome of unicompartmental knee arthroplasty (UKA) is an important question. UKA is a reliable surgical procedure, provided it is technically well-performed and utilized for appropriate indications. For many patients, UKA is a good alternative to total knee arthroplasty (TKA) or high tibial osteotomy (HTO) [1–3]. Strong evidence that gender influences outcomes following UKA could alter UKA selection criteria. Several previously published series report no influence of gender on results of UKA [4–10]. However, Deshmukh and Scott [11] in a review article caution that worse outcomes may be noted among younger men, particularly those that are heavier. Tabor et al. [12] showed higher implant survival among women after 10 years but these results could be related to the increased height and weight of male patients, the severity of the clinical presentation, patient activity level, or patient age. No prior series has been specifically designed and matched to compare outcomes based on gender. The purpose of this study was to elucidate the effect of gender on the clinical outcome of UKA while controlling for other variables that may affect outcome. 2. Materials and methods 2.1. Patient population Between 1988 and 2006, 2280 TKA's and 257 UKA's were carried out in our department. Fifty-six of the patients undergoing UKA were male (21.7%), and 201 were female (78.3%). The 40 males for whom at least 2-year follow-up data were available were matched with a group of 40 female patients randomly selected from the 137 women with at least 2-year follow-up data available. These two populations were comparable in terms of age, body mass index (BMI), diagnosis, preoperative IKS scores, history of previous joint surgery, preopera- tive hip–knee–ankle (HKA) angle, severity of osteoarthritis (Ahlback grade), patellar height (Blackburn–Peel index) and tibial slope (Table 1). The only significant differences noted between the two groups were increased weight and height in the male group and a slightly larger flexion contracture in the male group (Table 1). 2.2. Surgical indications We performed UKA in patients with symptomatic Ahlback stage 2 or 3 tibiofemoral osteoarthritis limited to one tibiofemoral compart- ment resulting in an HKA angle between 170 and 194°. We avoided UKA in patients with a flexion contracture of 10° or more, flexion of less than 100°, or weight greater than 85 kg. High tibial osteotomy was generally utilized rather than UKA in patients younger than age 65. However, the only absolute contraindications to UKA were rheumatoid arthritis and knee ligament insufficiency. 2.3. Surgical technique All patients were operated on using the same surgical technique under the supervision of the senior author. A medial or lateral parapatellar subvastus approach was used, according to the affected compartment. Care was taken not to overcorrect the mechanical axis. The HLS Uni (Tornier, Grenoble, France) was used in all cases. This implant consists of an all-polyethylene tibial component in combina- tion with resurfacing of the femoral condyle. All implants were cemented. The Knee 19 (2012) 176–179 ⁎ Corresponding author at: Centre Albert Trillat, Hôpital de la Croix Rousse, 103 Grand Rue de la Croix Rousse, 69004, Lyon, France. Tel.: +33 4 72 00 41 56; fax: +33 4 72 07 17 96. E-mail address: sebastien.lustig@gmail.com (S. Lustig). 0968-0160/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.knee.2011.03.001 Contents lists available at ScienceDirect The Knee