Three-Dimensional In Vivo Kinematic Analysis of Kienböck Disease Treated with Arthroscopic Lunate Excision.

Purpose: Treatment options for advanced stage Kienböck disease primarily involve lunate excision, either in the context of proximal row carpectomy or in association with partial wrist fusion. This study aimed to investigate the in vivo three-dimensional carpal kinematics following arthroscopic lunate excision.

Methods: We analyzed carpal translation and rotation of the affected wrist in five patients who underwent arthroscopic lunate excision for stage IIIC Kienböck disease. Our dynamic computed tomography image-based analysis focused on determining the centroid position of the scaphoid, triquetrum, and capitate and measuring the rotational angles of each carpal bone relative to the radius. These postoperative measurements data were compared with those derived from five healthy subjects. Furthermore, the joint contact area was visualized to assess the congruity of the radiocarpal and midcarpal joints.

Results: Wrists in which the lunate was arthroscopically excised were found to have significantly different carpal kinematics compared to normal subjects. Specifically, scaphoid-triquetrum, ulno-triquetrum, and radio-capitate distances decreased during ulnar and radial deviation. After surgery, the scaphoid tended to be limited in its extension, presenting a flexed position. Lunate-excised wrists demonstrated no apparent deviation of the contact area in the radioscaphoid or midcarpal joint.

Conclusions: Although postarthroscopic lunate excision alters normal carpal kinematics, the joint congruity is maintained in the short-term.

Type of study/level of evidence: Therapeutic V.