RESEARCH - 3D kinematics of the rheumatoid wrist after partial arthrodesis

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J Bone Joint Surg Am. 2009 Sep;91(9):2180-7.

Three-dimensional kinematics of the rheumatoid wrist after partial arthrodesis.

Arimitsu S, Murase T, Hashimoto J, Yoshikawa H, Sugamoto K, Moritomo H.

Department of Orthopaedic Surgery, Osaka University, Osaka, Japan.

BACKGROUND: Partial arthrodesis of the wrist, such as radiolunate and

radioscapholunate arthrodesis, is intuitively more appealing for the

treatment of the rheumatoid wrist than total arthrodesis is because it

preserves some motion. However, wrist kinematics after partial

arthrodesis are incompletely understood. The purpose of the present

study was to evaluate the kinematics of the radiocarpal and midcarpal

joints of rheumatoid wrists with use of three-dimensional computed

tomography before and after partial arthrodesis.

METHODS: We selected ten wrists that were affected by rheumatoid

arthritis in which the radiolunate joint was severely damaged but the

midcarpal joint congruities were relatively well preserved. Six

radiolunate and four radioscapholunate arthrodeses were then

performed, with preservation of the joint congruity between the

scaphoid, lunate, and capitate. We acquired in vivo three-dimensional

kinematic data during wrist flexion-extension preoperatively and

postoperatively with use of computed tomography and a markerless

bone-registration technique. Postoperative midcarpal joint congruity

and range of motion were compared with preoperative values.

RESULTS: The mean range of global wrist motion was 48 degrees +/- 21

degrees after radiolunate arthrodesis and 47 degrees +/- 14 degrees

after radioscapholunate arthrodesis. Midcarpal joint congruities and

motion between the scaphoid, lunate, and capitate were well preserved

in all ten wrists. The postoperative range of capitate motion relative

to the lunate was 109% of the preoperative value after radiolunate

arthrodesis and 88% after radioscapholunate arthrodesis. The

directions of capitate motion relative to the lunate after both types

of partial arthrodesis were significantly more oblique than before the

arthrodeses, changing from radiodorsal to ulnopalmar along the

so-called dart-throwing motion plane (p < 0.05).

CONCLUSIONS: The results of this kinematic analysis, which showed that

midcarpal motion occurred in the dart-throwing motion plane, may

support the use of radiolunate and radioscapholunate arthrodeses as an

alternative to total wrist arthrodesis in patients with symptomatic

rheumatoid arthritis of the wrist.

PMID: 19723995

http://www.ncbi.nlm.nih.gov/pubmed/19723995

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