Abstract
Introduction: Total knee arthroplasty (TKA) in patients with skeletal dysplasia is challenging due to the anatomic variances and deformities. The purpose of this review is to understand the technical issues involved in treating these patients.
Methods: Clinical notes, operative reports, and radiographs were retrospectively reviewed of 12 knees in 8 patients: 3 achondroplasia patients (one with bilateral 10° varus deformities, one with a 30° varus deformity in one knee and 25° varus deformity in the other knee, one with a 14° varus deformity); 3 multiple hereditary exostosis patients (one with bilateral 45° valgus deformities, one with a 45° valgus deformity in one knee and 15° valgus deformity in the other, one with a 11° valgus deformity); and 2 osteogenesis imperfecta patients (one with a 25° varus deformity, one with a 17° valgus deformity).
Results: Surgical exposure required preoperative placement of soft-tissue expanders to avoid wound complications (1 knee), quadriceps snip (2 knees), and hardware removal (1 knee). Intraoperative balancing of the knee was more complex requiring a lateral epicondylar osteotomy (3 knees), medial release (6 knees), lateral retinacular release (6 knees), and proximal realignment to improve patellar tracking (1 knee). 5 knees required a constrained insert, 2 required tibial augments, one required use of cement and screw technique, and one required modification of an all-polyethylene tibia to accommodate the deformed tibial anatomy. 2 knees required custom tibial components. Complications included 2 peroneal nerve palsies which resolved 3 months postoperatively. Range of motion preoperatively averaged 103° (range 45 to 130°) and 100° postoperatively (range 85 to 120°). All patients were pain-free at their last followup (average follow-up 3.9 years).
Conclusion: Special considerations must be made regarding surgical exposure, ligament balancing, implant selection, and anticipation of complications due to the unusual deformities when performing TKA in skeletal dysplasia patients.
Correspondence should be addressed to Diane Przepiorski at ISTA, PO Box 6564, Auburn, CA 95604, USA. Phone: +1 916-454-9884; Fax: +1 916-454-9882; E-mail: ista@pacbell.net
