gms | German Medical Science

Objectives: Failures of a total TM prosthesis are mainly due to cups non embedment. In this cases many authors suggest the ablation of the implant followed by trapezectomy. We present a way to preserve the trapezium and thereby preserve thumb length, stability, and grasp. This technique is not indicated if the trapezium is fractured.

Method: 37 patients are included in this series, 2 cup loosening and 35 cup non embedment. The series includes 25 Electra , 4 Maia, 3 Arpe, 3 Isis, 2 others implants. It starts from 2005.

All the cases had the same procedure. Through a dorsal approach, ablation of the implant avoiding a metacarpal corticotomy is performed. The reconstruction of the trapezium is made by filling it with bone chips from the ipsilateral radius .The first metacarpal basis is resurfaced through the interposition of a CMI pyrocarbon implant. The void created inside the first metacarpal is filled by the CMI stem sometimes completed with apatite. The cicatricial carpo-metacarpal capsulae is tightened with resorbable suture , any complementary ligamentoplasty is employed. Immobilisation is done for 3 weeks.

Results: Evaluation was done on X rays, pain, satisfaction, mobility, grasp. Owing to belated beginning 18 cases could not be rewieved.

Radiologic evolution shows a corticalisation in contact with pyrocarbon of the chips grafted inside the trapezium. None extrusion of the stem inside the first metacarpal was noticed, none osteophytes or calcification found in the neojoint.

Clinically the main fact is the preservation of thumb opposition tests and grasp force (diagram 3).

Complications: (diagram 4) none on the donor site, 3 neuritis of the radial sensory branch, 2 SDD

Conclusion: This technic is easy to drive, in one time surgery, in one on only operative site.

Since for such difficult cases one reprise is already too much, it stands out to become in our practice a "gold standard" for that situations.