Total Knee Arthroplasty in Patients Who Have Skeletal Dysplasia: A Center’s Experience with a Mean 9 Year Follow-Up

Abstract

BackgroundTotal knee arthroplasty (TKA) in patients who have skeletal dysplasia is a technically challenging surgery due to deformity, joint contracture, and associated co-morbidities. Patients presenting with this condition have traditionally been treated with conservative measures, leading to poor outcomes. The aim of this study was to follow up on patients who had skeletal dysplasia following total knee arthroplasty, specifically with regards to clinical outcomes. MethodsA total of 31 knees (22 patients) with skeletal dysplasia that had undergone total knee arthroplasty in our institution were included in our study. The mean follow-up from index surgery was 110.3 months (range; 20 to 291). The type of dysplasia, implant used, and clinical outcomes with patient-reported outcome measures (PROMs) are presented. ResultsThere were eight patients (36.3%) who had a diagnosis of achondroplasia, followed by multiple epiphyseal dysplasia (31.8%) and spondyloepiphyseal dysplasia (22.7%). There were fourteen men and eight women who had a mean age of 51 years (range, 28 to 73). Custom implants were required in twelve cases (38.7%), custom jigs were used in six cases (19.4%), and robotic assisted surgery was used in two (6.5%) total knee arthroplasties. Hinged prostheses were used in seventeen cases (54.8%), posterior stabilized in nine (29.0%), and cruciate retaining implants in five (16.1%). There was one patient who sustained an intra-operative medial tibial plateau fracture treated with concomitant open reduction and internal fixation. There was one revision that occurred during the follow-up period with a patella resurfacing for continued anterior knee pain. Post-operatively, Oxford knee scores improved on average by 12.2 points. The 10- and 20-year all-cause revision-free survival was 96.8 respectively. ConclusionDespite the technical challenges and complexity associated with this unique patient cohort, we demonstrated excellent implant survivorship and clinical outcomes post-total knee arthroplasty with mid- to long-term follow up of over 20 years. We recommend pre-operative cross-sectional imaging for precise planning and implant templating with multidisciplinary team decision-making. Despite our results, functional outcomes remain inferior to primary arthroplasty within the general population, though we still recommend this treatment modality to appropriately counseled patients.