Overcoming the Technical Challenges of Total Knee Arthroplasty in Patients Affected by Hereditary Multiple Exostoses: a Case Report and Literature Review

Abstract

Abstract Hereditary multiple exostoses (HME), also known as familiar osteochondromatosis or diaphyseal aclasis, are an autosomal dominant inherited genetic pathology that is characterized by the presence of multiple benign osteochondromas. Knee deformity is common in patients with HME, with nearly a third of patients developing genu valgus. Total knee arthroplasty (TKA) has been used to correct valgus deformities with advanced knee osteoarthritis (OA). However, concomitant limb deformities and altered anatomy of the knee make this surgery particularly challenging. We present a case report and a mini-review of the literature on this topic. We present the case of a 50-year-old Caucasian woman, affected by hereditary multiple exostoses, who came to our attention for progressive pain in the right knee. Upon further examination, the knee had a prominent valgus alignment, concomitant valgus instability, and flexion contraction. The patient was treated with total knee arthroplasty using a semi-constrained design. The patient was re-evaluated at 24-month follow-up, and there were no signs of implant loosening, the knee function improved significantly, and the patient was very satisfied. Given the recurring technical difficulties of such procedure in these patients, we describe our experience as well as the need for preoperative planning, the use of appropriate constraint when required, the high frequency of ligament instability, bony defects, and patellar maltracking. TKA must be considered when necessary, in these patients, as good to excellent clinical results can be achieved and maintained, allowing for significant improvements in quality of life. Core Tips - TKA in HME-affected patients carries specific but manageable challenges. - Due to bone deformities and frequent severe valgus knee alignment, TKA should be considered even in younger patients. - Revision implants provide the flexibility and the necessary fixation, not always achievable with primary implants. - Bigger size components may be necessary in HME patients compared with patients of the same height. - Lateral ligament releases may often be necessary due to long-standing valgus deformity. If stability cannot be achieved, the use of a hinged implant should be considered. - Cementation of the metaphysis or the use of sleeves can provide additional rotational stability to the implant.