Developments in trapezium Replacements

The purpose of this update is to report on a variety of topics related to trapezium implants that have been investigated during the past three years. The keyword trapezium implant was utilized to query the PubMed database of the U.S. National Library of Medicine. From the resulting list, papers published from the beginning of January 2012 through the beginning of April 2015 were reviewed. The twenty-three studies identified are reviewed here and referenced at the end of the review. Based on level of evidence criteria for therapeutic studies as adopted by the American Academy of Orthopedic Surgeons, the most frequent level of evidence for reviewed clinical studies was Level IV (13/19 studies), followed by Level III (4/19), and Levels II (1/19) and I (1/19). Introduction: surgical treatment options for trapeziometacarpal osteoarthritis The trapeziometacarpal joint is one of the most common sites of osteoarthritis in the human body, particularly in postmenopausal women.1-3 Multiple surgical techniques exist to address this problem, including arthrodesis, implant arthroplasty, and trapeziectomy with or without ligament reconstruction/tendon interposition.2 Trapeziectomy, first described by Gervis in 1949, has long been the classic surgical treatment for trapeziometacarpal osteoarthritis, and is effective for reducing pain but leads to longer functional recovery times and loss of strength.4 Trapeziectomy with ligament reconstruction is now considered by some to be the gold standard for treatment and provides both shortand long-term relief of pain, with one study reporting excellent pain relief in 23/24 patients at an average of 9.4 years followup.5,6 However, disadvantages of this procedure include proximal migration of the thumb metacarpal after trapezial resection, resulting in reduced pinch strength.7 Meanwhile, advancements in biomechanics and materials research have yielded new implant designs over the past five decades8 and have challenged the gold standard of trapeziectomy, such as by calling into question the need for reconstructing the ligament.5 A prospective study comparing joint prostheses versus trapeziectomy with ligament reconstruction at 1-year follow-up reported reduced pain and improved strength and range of motion for implant arthroplasty patients.9 However, there is no current consensus that implant arthroplasty provides superior pain reduction or improved function compared to simple resection arthroplasty.10 Trapeziometacarpal arthrodesis Arthrodesis remains a viable option for treatment of trapeziometacarpal osteoarthritis, but it is associated with decreased range of motion and transfer of force to proximal joints, and its primary complication is nonunion in approximately 13% of cases.2,7 Harston et al. investigated the outcome of a new surgical technique for arthrodesis described in 2010, involving the creation of a V-shaped osteotomy at the base of the first metacarpal and a matching osteotomy of the trapezium to provide a more stable fusion site.2 The authors studied data from a 2-year follow-up of 21 patients treated with this technique, and reported an 83% complete fusion rate, along with improvement in range of motion and strength, with no infections or reoperations for reunion. 19 of 21 patients were satisfied with the procedure, and the authors conclude that arthrodesis using V-shaped osteotomy can be a successful, reproducible, and strength-preserving procedure with a low nonunion rate. Trapeziectomy with ligament reconstruction/tendon interposition Szalay et al. examined the utility of the Mini TightRope (Figure 1), which allows for suspension of the first metacarpal following trapeziectomy in a retrospective study with 31 patients.11,12 74.2% of the patients obtained good or very good results, based on clinical and radiological examination as well as Buck-Gramcko scores. In 2 patients, the Mini TightRope had to be removed due to strong pain and proximalization of the first metacarpal, but the authors reported the procedure to be an overall success in the majority of patients. Vandenberghe et al. sought to compare long-term outcomes of trapeziectomy with reconstruction/interposition versus implant arthroplasty using questionnaire results from 322 patients reporting their degree of pain, impairment, patient satisfaction, and disability.13 They found no significant difference in any of these measures, and recommended trapeziectomy over prostheses as the first choice of surgical treatment, citing the greater cost of prosthetic implants and the absence of data supporting their superiority in terms of outcomes. However, a study by Jager et al. found the opposite, reporting better short-term outcomes for the MAIA prosthesis compared to trapeziectomy-interposition.4 In a prospective analysis of two comparable cohorts of 47 (prosthesis) and 27 (trapeziectomy) patients, the authors found superior mobility, pain reduction, satisfaction, strength, and functional scores in the prosthesis group, as well as better improvement of pinch strength and correction of subluxation. Prosthetic arthroplasty options Although the advantage of using prostheses has not yet been clearly established, prosthetic arthroplasty can still provide some theoretical benefits compared to trapeziectomy with ligament reconstruction, including preservation of joint biomechanics and range of motion, avoidance of metacarpal subsidence, and immediate stability.14 Vitale et al. provided a summary of the trapezium prosthetic options that have emerged over the past 5 decades.14 First generation implants were primarily Swanson silicone prostheses, which Orthopedic Reviews 2017; volume 9:7196 Correspondence: Adam E.M. Eltorai, Warren Alpert Medical School, Brown University, Box G-9247, Providence, RI 02903, USA. Tel: +1-401-863-3330 Fax: +1-401-863-5096. E-mail: [email protected]