Arthroplasty for patients with dysmelia
Patients with glenohumeral joint dysplasia have limited treatment options. Smaller, altered anatomy and fibrosis of the capsule and ligaments make surgery extraordinarily difficult. In addition, the treatment must adapt to the requirements of life and delay the progression of the disease. Arthrodesis of the shoulder would reduce pain. However, in combination with coexistent ankylosis of the elbow or wrist joint, it results in a total loss of functionality of the limb. Arthroplasty with stemmed or reverse shoulder prosthesis is not an adequate procedure for patients with glenohumeral joint dysplasia. New concepts for anatomical reconstruction have been developed over the years to restore anatomy without loss of the humeral bone stock [
14‐
16]. Humeral resurfacing arthroplasty can be an alternative to conventional arthroplasty. Resurfacing arthroplasty entails less invasive surgery, shorter operation times, little to no risk of periprosthetic stem fractures or loosening of the glenoid component and preservation of bone stock without loss of humerus length. This allows for easier revision surgery, if necessary. Meanwhile, humeral head resurfacing prostheses have been used in many shoulder diseases including primary and posttraumatic osteoarthritis, avascular necrosis, rheumatoid arthritis and cuff-tear arthropathy. These indications have proven useful in younger patients [
17,
18], but are not suitable for advanced necrosis or deformation of the humeral head [
19]. Due to anatomic anomalies - most notably dysplasia of the glenoid and no well-defined rotator cuff - a total shoulder prosthesis could not be implanted. Anchoring a glenoid component, either anatomical or reverse, was not feasible due to the lack of glenoid bone stock. In addition, it was not possible to use bone-sparing glenoid components as suggested by Sears et al. or to reconstruct the socket of the glenoid in all three thalidomide patients [
20]. Consequently, the patients received hemiarthroplasties. In order to expose the anatomic neck of the proximal humerus and to excavate humeral head osteophytes, an improvement of external rotation using a sufficient soft tissue release was performed. The decisive argument for resurfacing arthroplasty is the possibility of having the free choice of retroversion as well as inclination angle. The lack of surgical landmarks requires substantial experience to avoid imprecise positioning of the prosthesis and improper soft tissue balancing. The difficulty in achieving arthroplasty stability is to perform a balancing act in the management of the bone and soft tissue in dysmelic patients.
Arthroplasty among patients with glenohumeral dysmelia is a rarely performed surgery, and as a result no long-term results are available. Only one source, Newman et al., reported a case of a 35-year-old woman with thalidomide-induced phocomelia. In 1999 he had predicted a rise of degenerative joint diseases in this population [
21]. Duralde et al. reported on two cases with Apert’s Syndrome and Erb’s palsy treated with resurfacing prostheses [
22]. ROM did not change significantly at follow-up, but arthroplasty resulted in high patient satisfaction and excellent pain relief. Mansat et al. treated 4 patients with not otherwise specified dysmelia using cup prostheses without glenoid resurfacing, even in cases of eccentric glenoid wear. They reported, that the worst results were obtained for rheumatoid arthritis and dysplasia (Constant 60 points; follow-up 33.7 months; mean age 62 years). A pain score of 11.8 points was reported according to Constant criteria of 15 points [
23]. This correlates with our patient series, which reported a mean pain of 13 points according to Constant criteria. Smith et al. reported on three cases of hemiarthroplasty with stemmed prostheses in a series of twelve patients with primary glenoid dysplasia [
24]. The mean age at onset of symptoms was 50 years with mean pain ratings on the visual analogue score of 5 out of 10 postoperatively. The follow-up time was not described. Due to of the lack of glenoid bone stock, inserting a glenoid component would have been difficult and the results were described as relatively disappointing compared with standard procedures. The premature development of osteoarthritis in patients with primary dysplasia of the glenoid has been described in the literature [
25,
26]. Allen et al. reported an update to the series by Sperling et al. [
3]. They treated 22 shoulders with glenoid dysplasia and secondary osteoarthritis using eight hemiarthroplasties. The authors recommended that glenoid deficiency and cartilage wear should be addressed at the time of shoulder arthroplasty in patients with glenoid dysplasia and glenoid problems necessitating revision surgery were frequent. Our experience would confirm this. We performed glenoid replacement in only one case in which a bone stock of the glenoid was suited to accept a glenoid component. Both Smith et al. and Allen et al. reported on a specific disease limited to the glenoid, in contrast to our series where the surrounding soft tissue was also involved [
24,
27].
Sewell et al. [
5] described a series of 13 shoulders in 10 patients. Five unconstrained TSAs, 4 linked (constrained) TSAs, and 4 HAs (2 stemmed and 2 resurfacing implants) were implanted. He was able to prove that arthroplasty provides the ability to improve pain and function and concluded that shoulder arthroplasty is a viable treatment option in patients with skeletal dysplasia. He explained that their high revision rate of 31 % was due to multiple pathologic joint processes compared to the general population.
A limitation of this study is the low incidence of disease, resulting in the small sample size, and making a randomized controlled setup unfeasible. The particular and varied shoulder anatomy of the individual patients is the reason for the heterogeneity of the prosthetic selection, which we feel is necessary to offer the patient the best treatment.