Wrist kinetics after scaphoidectomy.

BACKGROUND: The scaphoid cannot be excised without generating substantial carpal dysfunction. The extent and nature of such a destabilizing procedure, however, has never been properly studied in the laboratory. METHODS: We used a six-degrees-of-freedom motion tracking device to quantify the changes in carpal alignment produced by isometric simultaneous loading of five wrist motor tendons in 12 fresh normal cadaver arms, before and after excising the entire scaphoid. FINDINGS: In the intact wrist, tendon loading consistently extended and supinated the capitate while flexing the triquetrum. After scaphoidectomy, the opposite rotations were always found: the capitate collapsed into flexion and pronation, whereas the triquetrum migrated proximally, while extending and radial deviating. All these changes were statistically significant. INTERPRETATION: Unless it is supplemented by some sort of midcarpal stabilization, scaphoidectomy alone is much too aggressive as a procedure to be considered a treatment option for wrist osteoarthritis. LEVEL OF EVIDENCE: Laboratory study. Not applicable.

Changes in intraosseous pressure at the distal femoral epiphysis induced by variations in knee-joint position and intracapsular saline infusion. An experimental study in dogs.

Hemodynamic changes at the distal femoral epiphysis measured by recording intraosseous pressure (IOP) were investigated in mature and juvenile dogs after changes in knee-joint position and intracapsular infusion of 3 ml isotonic saline solution. Juvenile and mature animals responded to infusion test with a similar 5-fold increase in intracapsular pressure. A 2-fold increase in IOP was found when knee-joint flexion passed from 30 degrees to complete flexion. In juvenile dogs, IOP values were lower than in adults both in complete knee flexion and during infusion test. The similar response to joint hyperpressure tests observed in adult and juvenile dogs suggests that the barrier effect of the growth plate for epiphyseal venous drainage has no major influence in the hemodynamics of the distal femoral epiphysis.

The place of intertrochanteric osteotomy in the treatment of idiopathic necrosis of the head of the femur.

The authors present their experience of the use of intertrochanteric osteotomy for the treatment of idiopathic necrosis of the head of the femur. The results obtained from 102 osteotomies performed on 81 patients with the disease are analysed. The mean follow-up is 4.2 years. The results show a statistically significant clinical improvement after operation. Patients presenting with Ficat and Arlet Stage II involvement fared much better than those with more severe changes. Better results were also seen in those with a necrosis angle of less than 200 degrees. No radiological improvement was seen although a high percentage showed no deterioration. The choice of treatment for the condition is discussed in the light of these results.