gms | German Medical Science

Although therapeutic medications and surgical treatment such as synovectomy may reduce symptoms of gonarthritis, they often fail to prevent joint destruction. The objective of this study was to examine the outcome of a new hinged prosthetic design in patients with rheumatoid arthritis.

The rotating hinge knee (Zimmer, Warzaw) was implanted in 54 patients (39 females, 15 males, average age 54.8 (25-67) years) with rheumatoid gonarthritis. Patella resurfacing was done in all patients. The rotating hinge knee is a modular prosthesis with a vertically coupling, a mobile polyethylene and uncemented intramedullary stems. The design is condylar loading with minimal loads on the hinge. The Lysholm score was used for clinical evaluation. Indications for the implantation were severe deformities and instabilities of the knee as well as severe flexion contracture and muscle atrophy. All patients were examined pre- and postoperatively after 3, 26, 52 and 78 weeks.

The preoperative Lysholm score showed an average of 22.1 (13-32) points. Postoperatively an average score of 49 (33-58) was achieved after 3 weeks, of 81 (65-91) after 26 weeks, of 82 (66-92) after 52 weeks and of 81 (66-90) after 78 weeks. Four complications occurred, 1 prosthesis infection, 1 periprosthetic fracture and 2 wound healing disorders. There was no radiographic evidence of loosening.

In rheumatoid patients with severely affected knee joints good early functional results are achieved using the rotating hinge knee design. Especially the good stability of the joint allows an early rehabilitation of the patients. The early results are encouraging, although the follow up is too short to accept as the final fate of the prosthesis.