Trends in Trapeziometacarpal Implant Design: A Systematic Survey Based on Patents and Administrative Databases

Effective shape of ball-and-socket prosthesis in restoring range of thumb motion for total thumb carpometacarpal joint arthroplasty: three-dimensional motion analysis

PURPOSE

Total joint arthroplasty (TJA) has often been used to treat thumb carpometacarpal (CMC) osteoarthritis (OA). However, guidelines for the CMC prosthesis shape remain unclear. This study aimed to identify the effective shape of a ball-and-socket prosthesis in restoring the range of thumb motion after TJA.

METHODS

The participants were 10 healthy young adult men (22-32 years; 26.8 ± 3.57 [mean ± SD]). CT scans were performed in eight static limb positions during abduction and flexion. We defined three design variables (offset R, height H, and neck rotation angle Φ) as the variables that determine the basic shape of the ball-and-socket prosthesis. The ideal values of these design variables were examined based on the results of a 3D motion analysis, which evaluated the change in the posture of the first metacarpal (r, h, and φ corresponding to R, H, and Φ, respectively) relative to the center of rotation (COR) during abduction and flexion. We also simulated the effect of these design variables on the range of thumb motion after TJA using 3D CAD.

RESULTS

We found that the values of r and h averaged over all limb positions were 6.92 ± 1.60 mm and 51.02 ± 1.67 mm, respectively, showing that these values remained constant regardless of limb position. In contrast, φ changed significantly. The simulation results indicated that Φ affected the range of thumb motion after TJA, and Φ = 0° relatively reproduced all limb positions compared to other values.

CONCLUSION

Our results suggested that the desirable values of R and H were the average of r and h over several limb positions and that Φ = 0° was effective in restoring the range of thumb motion after TJA. Our results will provide surgeons with new guidelines for selecting a prosthesis.

MAÏA Trapeziometacarpal Joint Arthroplasty: Clinical and Radiological Outcomes of 76 Patients With More Than 10 Years of Follow-Up

PURPOSE

Trapeziometacarpal (TMC) joint replacement has become a valid option in the therapeutic arsenal of TMC joint osteoarthritis in Europe. Good mid-term results of the MAÏA TMC joint prosthesis suggested that it is a reliable procedure. This study aimed to assess the long-term results of this modular uncemented ball-and-socket hydroxyapatite-coated implant.

METHODS

This single-center retrospective study evaluated 92 MAÏA TMC joint prostheses in 76 patients with a minimum of 10 years of follow-up. Indications for the procedure were painful TMC joint osteoarthritis both at rest and during activity, despite nonsurgical treatment for more than six months. Pre- and postoperative clinical and radiographic outcomes were compared.

RESULTS

Mean follow-up was 134 months (range: 120-158 months). Mean age at the time of surgery was 67 years (range: 53-84 years). The cohort comprised 86.8% of women (n = 66). The mean Quick Disabilities of the Arm, Shoulder, and Hand score improved from 61.3 ± 17.1 to 19.6 ± 16. Range of motion was restored, and postoperative mobility was comparable with that of the contralateral side. Final Kapandji opposition score was almost normal (9.2 ± 0.7). Final key pinch and grip strength improved by 26% and 39%, respectively. Eight implants were surgically revised, six for trapezium cup loosening and two for instability because of polyethylene wear. Three cases of traumatic fracture of the trapezium in older patients were successfully treated with a cast for eight weeks. Five of 26 (20.8%) cases of preoperative-reducible z-deformity were not totally corrected after surgery. The Kaplan-Meier survival over 10 years was 88% (95% confidence interval: 84-93) versus 93% (95% confidence interval: 87-98) over 5 years.

CONCLUSIONS

MAÏA TMC joint prosthesis is a reliable long-term surgical procedure for TMC joint osteoarthritis, improving overall function beyond 10 years.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

[Current Trends in the Implantation of the Touch Prosthesis at the Thumb Carpometacarpal Joint: Results of the 1st German-Speaking User Meeting]

The introduction of the new generation of thumb carpometacarpal (CMC I) joint implants for the treatment of CMC I osteoarthritis has significantly broadened the scope of hand surgery in recent years. However, the technical demands of the procedure and the many details that need to be considered require appropriate training and a learning curve. To share experiences with the Touch CMC I prosthesis, we held the first German-speaking CMC I joint prosthetics user meeting in Zurich. After some basic introductory lectures on biomechanics and the principles of prosthetic fitting of the CMC I joint, the various challenges associated with CMC I joint prosthetics were discussed in interactive expert panels. Subsequently, cases were discussed in small groups under expert guidance and the respective conclusions were discussed in plenary. The main results of this symposium are summarised in this manuscript.

Proposed Radiographic Parameters to Optimize Clinical Outcomes in Trapezio-Metacarpal Prosthesis Placement Using CT Imaging, with 1-Year Follow-Up

PURPOSE

Addressing trapezio-metacarpal (TMC) osteoarthritis often involves considering TMC joint replacement. Utilizing TMC prostheses offers advantages such as preserving the thumb length and more accurately replicating the thumb's range of motion (ROM). TMC prostheses have an intrinsic risk of dislocation and aseptic loosening. Analyzing pre- and postoperative imaging can mitigate complications and improve prosthetic placement, providing insights into both successes and potential challenges, refining overall clinical outcomes.

MATERIALS AND METHODS

We conducted a prospective analysis of 30 patients with severe TMC arthritis treated with a Touch© (Kerimedical, Geneva, Switzerland) prosthesis in 2021-2023: X-ray and CT protocols were developed to analyze A) the correct prosthesis placement and B) its correlation with clinical outcomes (VAS, Kapandji and QuickDASH scores) by performing Spearman correlation analysis.

RESULTS

The average differences in trapezium height and M1-M2 ratio pre- and post-surgery were, respectively, 1.8 mm (SD ± 1.7; p < 0.001) and 0.04 mm (SD ± 0.04; p = 0.017). Pre-to-postoperative M1 axis length increased by an average of 2.98 mm (SD ± 3.84; p = 0.017). Trapezial cup sinking, indicated by the trapezium index, measured 4.6 mm (SD ± 1.2). The metacarpal index averaged at 11.3 mm (SD ± 3.3). The distance between the centers of the trapezium distal surface and the prosthesis cup was 2.23 mm (SD ± 1.4). The Spearman correlation analysis gave the following results: negative correlations were highlighted between postoperative VAS scores and the M1/M2 ratio and residual trapezium height (correlation coefficient: -0.7, p = 0.03 and -0.064, p = 0.03, respectively) at 6 months; a negative correlation was found at the 3-month mark between QuickDASH and the trapezium residual height (correlation coefficient: -0.07, p = 0.01); and a positive correlation was found for the trapezium index at 1 month (correlation coefficient: 0.07, p = 0.03) and 3 months (p = 0.04) using the Kapandji score. Similarly, we found a positive correlation between the distance between the prosthesis and trapezium centers and QuickDASH score at 1 and 3 months (correlation coefficient: 0.066, p = 0.03; correlation coefficient: 0.07, p = 0.05, respectively) and a positive correlation between prosthesis axis and the residual first metacarpal angle with QuickDASH score at 3 months (correlation coefficient: 0.07, p = 0.02).

CONCLUSIONS

Pre- and postoperative systematic imaging analysis should become a method for predicting complications and guiding recovery in TMC prosthesis: CT imaging could provide us with radiographical landmarks that are intrinsically linked to clinical outcomes. Further research is necessary to fuel a protocol for the correct intraoperative TMC prosthesis implantation.

Complications of prosthesis versus trapeziectomy in trapeziometacarpal joint arthritis: A systematic review

OBJECTIVE

Thumb osteoarthritis is a frequent pathology, mainly affecting the elderly. The surgical treatment initially described and having proved its worth is total trapeziectomy. Since the advent of trapeziometacarpal prostheses, several studies showed the non-inferiority of this technique on clinical criteria, with superiority in bone sparing, although neither technique demonstrated overall superiority. We therefore examined the specific complications of each surgical technique by analyzing their nature and prevalence through a review of the literature to compare them on these new parameters.

METHODS

Seventy-four of the 320 articles reviewed were included, 38 of which concerned trapeziectomy, and 36 concerned prostheses, for a total of 4,865 patients. They were original studies, involving adults undergoing trapeziometacarpal arthroplasty or trapeziectomy, published after 2015, reporting at least one well-described complication.

RESULTS

6.13% of trapeziectomies presented severe complications (in particular thumb collapse and metacarpophalangeal hyperextension), 3.31% moderate complications and 1.90% minor complications, leading to a 2.0% revision rate. 23.88% of prostheses had severe complications (loosening, dislocation and wear), 5.06% moderate complications and 1.36% minor complications, leading to a 12.8% revision rate. In addition, we analyzed more recent prosthesis designs separately, and found lower prevalence of severe complications (16.56%) and revision surgery (4.3%).

CONCLUSION

Revision surgery for trapeziometacarpal prostheses is usually only a standard trapeziectomy with the same follow-up as first-line trapeziectomy, whereas revision surgery for trapeziectomies is much more complex and the results are uncertain. For this reason, we would reserve total trapeziectomy for revision surgeries and patients with low functional demand for whom a second surgery is not desirable. Further studies could confirm this attitude, especially focusing on the latest generation of dual mobility implants.

LEVEL OF EVIDENCE: 1

A quantitative measurement of trapeziometacarpal joint pressure using a cadaveric model of lateral pinch

Trapeziectomy is performed for trapeziometacarpal (TMC) arthritis but decreased lateral pinch strength is a major source of discomfort after the surgery. The magnitude of the decrease is unclear, however, and how the pressure changes in the TMC joint is unknown. To investigate this relationship, we designed a cadaveric study to measure TMC joint pressure using a lateral pinch model, and quantitatively evaluated the effect of trapeziectomy on the pressure measurements. For 10 cadaveric forearms, physiologic forces were applied across the thumb TMC joint by loading five tendons, thereby simulating lateral pinch. Using pressure sensors, we measured the lateral pinch pressure and TMC joint pressure, which averaged 10.1 (range, 4.2-16.2) kg/cm² and 2.0 (range, 0.8-4.4) kg/cm² , respectively. A significant correlation between the measurements was found, with an average ratio of 19% (range, 10%-27%). After trapeziectomy and interposition of the tendon ball using flexor carpi radialis, the pressure measurements were repeated under the same conditions. Significant changes were found, which averaged 5.1 (range, 1.7-10.7) kg/cm² for lateral pinch pressure and 15.0 (range, 5.6-25.6) kg/cm² for TMC joint pressure. In conclusion, TMC joint pressure could be measured as the ratio relative to lateral pinch pressure using a cadaveric model. After trapeziectomy, the lateral pinch strength decreased, whereas the TMC joint pressure increased.

Optimal Center of Rotation for Ball-And-Socket Thumb Carpometacarpal Arthroplasty Identified Using Three-Dimensional Kinematic Analysis: A Pilot Study

Total joint arthroplasty is one of the surgical option for thumb carpometacarpal (CMC) joint arthritis, however the optimal position the center of rotation (COR) has not been quantified. The purpose of this study is to identify ideal ball-and-socket thumb carpometacarpal joint implants and the optimal position of the COR. We obtained eight right thumb computed tomography images each from ten healthy men, comprising four images each of thumbs at various angles of flexion-extension and abduction-adduction. We reconstructed 3D bone models on 3D CAD, created virtual ball-and-socket implants with three variables (neck offset, implant height, neck rotation), and found the optimal COR where the position change in the COR was smallest across various thumb positions. When the offset was 4.5 mm, neck rotation angle was 130.6° from the radial side to the palmar side of the first metacarpal, and implant height from the distal end of the metacarpal was 43.6 mm, we could restore almost normal kinematics. This study could serve as a reference for implant development and surgical technique guidelines.

Initial survival of the Isis® total trapeziometacarpal prosthesis with conical trunk threaded cups

INTRODUCTION

The treatment of trapeziometacarpal osteoarthritis through the implantation of total trapeziometacarpal prostheses is in continuous expansion. The Isis® prosthesis is a trunk-conical threaded anchorage prosthesis. Our objective was to assess the functional results and survival of this implant for at least one year of follow-up.

MATERIAL AND METHOD

Prospective study on 53 Isis® prosthesis, implanted from april 2014 to january 2019. The Van Cappelle functional test, pain, strength, mobility, return to previous activity, radiological variables and placement of the trapezial component were evaluated. The surgical technique was performed with a guide wirefocused on the trapezius and control of the scopia. Observed complications were recorded and statistical analysis was performed.

RESULTS

Fifty-one implants (49 patients) were reviewed. Mean follow-up was 2.1 years (1-5.7). Van Cappelle's test, pain, mobility, and grip and clamp strength improved significantly, as did the distance between the metacarpal head and the trapezius base; 96% of the patients returned in less than 6 months to their activities. Minor complications, 3 De Quervain's tendinopathy and 2 intra-operative metacarpal and 2 trapezium fractures were recorded, and one carpal tunnel syndrome. There was no dislocation, mobilization, or implant infection.

CONCLUSIONS

The functional results of the Isis® prosthesis are excellent in the short term, far exceeding the first year of 100% of survival. The complications that arose were minor and few. The anchorage and placement of the trapezial component guided by scopia seem to be crucial for the good result.

Primary endoprosthetic replacement of the arthritic CMC-1 joint

OBJECTIVE

Osteoarthritis of the carpometacarpal (CMC)-1 joint is a common condition that can cause significant pain and functional problems. When nonoperative management fails, surgery may be indicated. Resection of the trapezium, often combined with soft tissue stabilization, is still considered the gold standard. But recovery time is often prolonged and a significant number of patients remain unsatisfied in the long term. Knowing that total endoprosthetic joint replacement is one of the most successful achievements of orthopedic surgery, many attempts have been made to produce a replacement for the CMC‑1 joint that provides a better outcome than trapeziectomy.

INDICATIONS

Eaton-Glickel stage 2-3 CMC‑1 osteoarthritis.

CONTRAINDICATIONS

Symptomatic pan-trapezial osteoarthritis (Eaton-Glickel stage 4), infection, young manual worker, poor bone quality or insufficient trapezium size.

SURGICAL TECHNIQUE

A dorsoradial approach to the CMC‑1 joint is used. Minimal resection of the trapezial and metacarpal articular surfaces, including osteophytes and loose bodies. Reaming of the trapezium and broaching of the metacarpal stem with dedicated instruments. Implantation of the endoprosthetic components. Selection of the correct neck length to ensure a stable joint. Closure of the capsule and skin.

POSTOPERATIVE MANAGEMENT

Immobilization of thumb for 2 weeks in a splint. Followed by a removable thumb CMC brace for 4 weeks, starting with gentle mobilization exercises. No forceful gripping or pinching the first 6 weeks.

RESULTS

A specific design-the uncemented, ball in socket, metal on polyethylene total joint replacement-has stood the test of time and successful long-term clinical and radiographic outcome results have been published. Recent comparative trials have shown better pinch strength, better pain relief and faster functional recovery, when compared to trapeziectomy with ligament reconstruction and tendon interposition. The incidence of complications such as dislocation, polyethylene wear and cup loosening is acceptable.

A radiostereometric and clinical long-term follow-up study of the surface replacement trapeziometacarpal joint prosthesis

Background

The aim of this study was to determine long-term survival and clinical outcomes of the surface replacement trapeziometacarpal joint prosthesis (SR™TMC) and to evaluate implant migration using radiostereometric analysis (RSA).

Methods

In this clinical long-term follow-up study outcomes of ten patients who received the SR™TMC joint prosthesis were evaluated using DASH and Nelson scores, Visual Analogue Scale (VAS) of pain, and key pinch strength. RSA-radiographs were obtained direct postoperatively and 6 months, 1, 5 and 10 years postoperatively and were analyzed using model-based RSA software.

Results

During follow-up, two early revisions took place. Mean pre-operative DASH and Nelson scores were 54 (SD 15) and 54 (SD 17), improved significantly after 6 months (DASH 25 (SD 20), Nelson 75 (SD 18)) and remained excellent during long-term follow-up in all patients with a stable implant. At final follow-up, clinical scores deteriorated clearly in two patients with a loose implant in situ.

Conclusions

Long-term survival of the SR™TMC joint prosthesis is relatively poor. However, clinical outcomes improved significantly in the short-term and remained excellent in the long-term in those patients with a stable implant, but deteriorated clearly in case of loosening. The role of RSA in TMC joint arthroplasty is potentially valuable but needs to be further investigated. Several challenges of RSA in the TMC joint have been addressed by the authors and suggestions to optimize RSA-data are given.

Trial registration

This study was registered in the Netherlands Trial Register (NL7126).