Acetabular coverage of the femoral head after triple pelvic osteotomy: no relation to outcome in 51 hips followed for 8-15 years.

In developmental dysplasia of the hip in adolescents and young adults, pelvic osteotomies aim to improve acetabular coverage of the femoral head by reorienting the acetabulum. We determined whether acetabular coverage is related to long-term clinical results after triple osteotomy of the pelvis. We used a previously published computer program (Konishi and Mieno 1993) which calculates three-dimensional coverage of the femoral head from plain anteroposterior radiographs. We studied the pelvic radiographs of 51 hips in 43 patients and the results were correlated with studies on clinical outcome (de Kleuver et al. 1997). Total acetabular coverage improved from a mean of 56% to 70%. We did not find a relationship between total acetabular coverage and long-term outcome, nor could we determine an optimal coverage. Reduced coverage of the posterolateral quadrant of the femoral head was related to a reduced score for walking ability (p = 0.03), and therefore care should be taken not to overcorrect the acetabulum forwards when attempting to improve the deficient anterior coverage. We challenge the concept that total acetabular coverage is a prerequisite for a good long-term outcome after triple pelvic osteotomy, and hypothesize that other factors such as the change in load across the hip are probably more important in determining the outcome.

A novel animal model to evaluate oxygen derived free radical damage in soft tissue.

We present a novel animal model which allows the continuous intra-arterial infusion in one hindlimb of non-anaesthetized rats, without inducing ischemia. Using this model the effect of continuous infusion (1 ml/h) for 24 h with tert-butylhydroperoxide (tert-BuOOH) at a concentration of 25 mM on soft tissue of the left hind limb was studied and compared to the effect of saline infusion (control group). The tert-BuOOH-infused foot showed increased skin temperature, increased circumference, redness of the plantar skin, impaired function and increased pain sensation, while in the contralateral foot and in rats only perfused with saline these signs of inflammation were absent (p < 0.01). Histological analysis of the left gastrocnemius muscle showed edema, muscle cell degeneration with a patchy distribution pattern and vascular damage. All these features increased in severity from 4 to 24 h tert-BuOOH infusion. After 24 h of tert-BuOOH infusion infiltration of neutrophils in the interstitium was observed. Vascular permeability, expressed as left to right gastrocnemius muscle 99mTc-IgG uptake ratio, was similarly increased after 4 h (2.09 +/- 0.26) and 12 h (2.04 +/- 0.08) of tert-BuOOH infusion compared to saline (1.05 +/- 0.08) (p < 0.001), and further increased after 24 h (3.84 +/- 0.13): (p < 0.001). In this animal model free radical-related soft tissue damage was induced, by continuous infusion of tert-BuOOH, followed by increasing necrosis and vascular permeability in skeletal muscle coinciding with neutrophilic infiltration.