SHORT TIME RESULTS OF TOTAL REPLACEMENT OF THE THUMB SADDLE JOINT IN RHIZARTHROSIS

Abstract

Pain free function of the thumb carpometacarpal (CMC) joint is essential for manual work. Osteoarthrithis of the thumb saddle joint is very common. Among different conservative and operative treatment options (ergotherapy, intraarticular infiltration, ligament reconstruction, resectionarthroplasty, arthrodesis, spacer), the implantation of a prosthesis is an alternative. This prospective study reports short time results of the uncemented hydroxilapatite coated Ivory prosthesis. The mean follow up time of the 21 patients was 12.1 months (range 6 to 18 months) and the mean age 57.2 years. The patients suffered from osteoarthritis of the thumb saddle joint stage II–III according to Eaton Littler. We evaluated the Disabilities of the Arm, Shoulder and Hand Score (DASH), pain with the visual analogue scale (VAS), clinical (abduction, flexion, strength) and radiological outcome.

The clinical results showed excellent pain relief with an improvement of the VAS from 7.3 preoperative to 0.8 postoperative (p< 0.05) and a decline of the DASH score from 42.9 to 6.05 points (p< 0.5). We measured an abduction with a mean of 47.5° and a flexion with a mean of 43.2°. The power of the fist grip was in mean 31.3 kg, of the key grip 6.4 kg. Radiological there were no signs of implant loosening. As complications occurred one posttraumatic trapezium fracture with luxation and one tendovaginits De Quervain.

The advantage of a total replacement of the CMC I joint, compared to the standard resection arthroplasty, is faster rehabilitation and preservation of the length of the thumb and so better strength. Our results are encouraging, but we have to wait for long time results mainly concerning implant loosening. In the case of the trapezium fracture with luxation we could remove the prosthesis and performed a resectionarthroplasty.