Long-term survival analysis of 191 MAÏA® prostheses for trapeziometacarpal arthritis

[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.

[Translated article] Experience in major complications with total trapezometacarpal prostheses

INTRODUCTION

The treatment of rhizarthrosis using trapeziometacarpal prostheses (TMP) is increasing. Complications may lead to loss of the implant and result in salvage surgery. Our aim was to assess major complications with the use of some TMP models and their rescue.

MATERIAL AND METHOD

Retrospective study on TMP implanted between 2006 and 2021. Models studied: Arpe®, Elektra®, Ivory®, Maïa®, Isis® and Touch®. Demographic data were assessed, implant placement by radiographic study, technical data, complications, salvage surgeries and final survival.

RESULTS

Review of 224 TMP, 45 Arpe® (95.5% survival, rate follow-up [R] 6-16 years), 5 Elektra® (80% survival, R 13-14), 14 Ivory® (92.8% survival, R 9-11), 7 Maïa® (100% survival, R 8-9), 115 Isis® (99.1% survival, R 1-8), 38 Touch® (100% survival, R 1-4). The medial angle of the dome with the proximal articular surface of the trapezium in the lateral plane, was: Arpe®: 8.85°, Elektra®: not assessable, Ivory®: 6.6°, Maïa®: 14.4°, Isis®: 3.8°, and Touch®: 5.95°. The Isis® was placed 100% with scopic guidance presenting a significantly lower angle respect to the medial angle of the dome with the proximal articular surface of the trapezium. As main complications, we observed 3.5% of dislocations and 4% of mobilisations, with the Elektra® being responsible for 47% of these. Nineteen salvage surgeries were performed, with 3% of the implants being lost.

CONCLUSIONS

Dislocation and mobilisation are the most observed complications, the Elektra® responsible for almost half of them. Correct placement and implant design appear to be crucial to avoid them in the short and long term.

Experience in major complications with total trapezometacarpal prostheses

INTRODUCTION

The treatment of rhizarthrosis using trapeziometacarpal prostheses (TMP) is increasing. Complications may lead to loss of the implant and result in salvage surgery. Our aim was to assess major complications with the use of some TMP models and their rescue.

MATERIAL AND METHOD

Retrospective study on TMP implanted between 2006 and 2021. Models studied: Arpe®, Elektra®, Ivory®, Maïa®, Isis® and Touch®. Demographic data were assessed, implant placement by radiographic study, technical data, complications, salvage surgeries and final survival.

RESULTS

Review of 224 TMP, 45 Arpe® (95.5% survival, rate follow-up [R] 6-16 years), 5 Elektra® (80% survival, R 13-14), 14 Ivory® (92.8% survival, R 9-11), 7 Maïa® (100% survival, R 8-9), 115 Isis® (99.1% survival, R 1-8), 38 Touch® (100% survival, R 1-4). The medial angle of the dome with the proximal articular surface of the trapezium in the lateral plane, was: Arpe®: 8.85°, Elektra®: not assessable, Ivory®: 6.6°, Maïa®: 14.4°, Isis®: 3.8°, and Touch®: 5.95°. The Isis® was placed 100% with scopic guidance presenting a significantly lower angle respect to the medial angle of the dome with the proximal articular surface of the trapezium. As main complications, we observed 3.5% of dislocations and 4% of mobilisations, with the Elektra® being responsible for 47% of these. Nineteen salvage surgeries were performed, with 3% of the implants being lost.

CONCLUSIONS

Dislocation and mobilisation are the most observed complications, the Elektra® responsible for almost half of them. Correct placement and implant design appear to be crucial to avoid them in the short and long term.

Thumb Arthroplasty as Reliable Long-term Solution for Trapeziometacarpal Osteoarthritis: A Minimum of 15 Years of Follow-up

BACKGROUND

In patients with symptomatic trapeziometacarpal (TMC) joint arthritis resistant to conservative treatment, surgical treatment can be advised. One of the many surgical treatment options is TMC arthroplasty. The Arpe prosthesis is one example of these TMC arthroplasties.

METHODS

This retrospective study evaluated patients who underwent TMC arthroplasty with the Arpe prosthesis after a minimum of 15 years of follow-up. Clinical, radiologic, and qualitative outcomes were assessed for 43 Arpe arthroplasties in 41 patients, of whom 2 had bilateral arthroplasties. The female to male ratio was 39:4. The mean follow-up time was 197 months (range = 180-225).

RESULTS

The cumulative survival rate after a mean of 16.5 years was 84%. Seven failures (16%) were registered, of which 5 during the first 3 years after primary surgery. All patients were successfully converted to a trapeziectomy. Quick Disabilities of the Arm, Shoulder and Hand score improved with 44.9 points and visual analogue pain score with 97% and 91% at rest and during exercise, respectively.

CONCLUSIONS

This series demonstrates that thumb arthroplasty is a reliable long-term solution for thumb base arthritis, with significant pain reduction and functional improvement, even after 15 years of follow-up.

Contribution to the study of stresses in the thumb column during key pinch grip

OBJECTIVES

The aim of this study was to calculate the stress acting on the trapeziometacarpal joint during an key pinch grip.

METHOD

We used profile X-rays of the thumb to measure the various bony and muscle lever arms. We assessed the angles of action of the muscular elements involved in the thumb column. Based on this data, we established a two-dimensional geometric model that enabled us to determine the forces at each joint level, as a function of stresses and muscular contributions. We were also able to calculate the participation of the different muscle groups in obtaining a balanced situation.

RESULTS

Our results, as a function of the degree of flexion of the interphalangeal and metacarpophalangeal joints, show a multiplying factor of 2.9-3.19 in relation to the key pinch grip force.

DISCUSSION

Previous studies modelling a key pinch grip are showed multiplying factors from 6 to 13 in relation to the key pinch grip force. They are not compatible with the characteristics of the polyethylene used for trapeziometacarpal prostheses, whereas numerous articles in the literature show survival rates that are more or less comparable to those of total hip prostheses. These studies required an excessive number of assumptions, which could lead to error. Our results are compatible with the results of trapeziometacarpal prosthesis and with those of a recent study measuring intra-articular trapeziometacarpal pressure in a cadaveric model. Our model allows us to test different configurations of the thumb spine depending on the degree of flexion of the interphalangeal and metacarpophalangeal joints.