A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis.

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

Modular tantalum augments for acetabular defects in revision hip arthroplasty.

UNLABELLED: Large acetabular defects can be reconstructed with various methods depending on size and location of the defect. We prospectively followed our first 37 patients in whom we reconstructed the acetabulum with a trabecular metal augment combined with a trabecular metal shell. Three patients died before completing the minimum 24 months followup while the remaining 34 were followed a minimum of 24 months (mean, 34 months; range, 24-55 months). All defects were classified according to Paprosky. Radiographic signs of osseointegration were classified according to Moore. Quality of life was measured with the SF-12, WOMAC, and Oxford Hip Score. There were 15 men and 19 women with an average age of 64 years. At a minimum of two years followup 32 of the 34 patients required no further surgery for aseptic loosening, while two had rerevision. Of the 32 patients who had not been revised, all had stable cups radiographically. All quality-of-life parameters improved. The early results with tantalum augments are promising but longer followup is required. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Enhanced gap filling and osteoconduction associated with alendronate-calcium phosphate-coated porous tantalum.

BACKGROUND: Porous tantalum has been shown to be effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity may be insufficient to allow adequate bone ingrowth. We hypothesized that local delivery of alendronate from porous tantalum would enhance the ability of the tantalum to achieve bone ingrowth when there is a gap between the implant and bone. We evaluated the effect of alendronate-coated porous tantalum on new bone formation in an animal model incorporating a gap between the implant and bone. METHODS: A cylindrical porous tantalum implant was implanted in the distal part of each femur in eighteen rabbits (a total of thirty-six implants) and left in situ for four weeks. Three types of porous tantalum implants were inserted: those with no coating (the control group), those with microporous calcium phosphate coating, and those coated with microporous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed with backscattered electron microscopy and fluorescent microscopy of undecalcified samples. RESULTS: The relative increases in the mean volume of gap filling, bone ingrowth, and total bone formation in the group treated with the porous tantalum implants coated with calcium phosphate and alendronate were 143% (p < 0.001), 259% (p < 0.001), and 193% (p < 0.001), respectively, compared with the values in the control group treated with the uncoated porous tantalum implants. The percentage of the length of the implant that was in contact with new bone in the group treated with the calcium phosphate and alendronate coating was increased by an average of 804% compared with the percentage in the group treated with the uncoated implants. CONCLUSIONS: The study demonstrated significantly enhanced filling of the bone-implant gap and bone ingrowth in association with the porous tantalum implants coated with calcium phosphate and alendronate.

Complex dorsal subluxation of the metacarpo-phalangeal joint of the thumb requiring open reduction: a case report.

The authors present an case of a thumb metacarpophalangeal joint dislocation which was made complicated by the interposition of the sesamoid bone which required open reduction. The intact volar plate prevented closed reduction. The anatomy and surgical management of this unusual case is described.