Total hip arthroplasty for adult hip dysplasia.

Preoperative planning is essential to define anatomy, clarify the operative approach and exposure, and ensure that suitable implants are available.Concerns exist regarding the long-term effectiveness and safety of hip resurfacing arthroplasty for the young dysplastic hip.In light of current evidence, concerns exist regarding the use of metal-on-metal articulations for hip arthroplasty in the young dysplastic hip.The ideal bearing surface is not known, although the longest data available support the use of metal-on-polyethylene.

The use of structural allograft in primary and revision knee arthroplasty with bone loss.

Bone loss around the knee in the setting of total knee arthroplasty remains a difficult and challenging problem for orthopaedic surgeons. There are a number of options for dealing with smaller and contained bone loss; however, massive segmental bone loss has fewer options. Small, contained defects can be treated with cement, morselized autograft/allograft or metal augments. Segmental bone loss cannot be dealt with through simple addition of cement, morselized autograft/allograft, or metal augments. For younger or higher demand patients, the use of allograft is a good option as it provides a durable construct with high rates of union while restoring bone stock for future revisions. Older patients, or those who are low demand, may be better candidates for a tumour prosthesis, which provides immediate ability to weight bear and mobilize.

Reflex inhibition during muscle fatigue in endurance-trained and sedentary individuals.

Reflex inhibition of the motoneuron pool following fatiguing contractions may be mediated by the build-up of byproducts of fatigue. Endurance training is accompanied by neuromuscular adaptations that would alter the production and/or clearance of metabolic substrates. The purpose of the study was to determine the extent of reflex inhibition during and after fatigue in endurance-trained individuals compared to sedentary controls. Subjects produced isometric ankle plantarflexion contractions at 30% of maximal voluntary contraction (MVC) until their MVC torque declined by 30%. H-reflexes were measured during a brief rest period every 3 min as well as superimposed upon the contraction every minute. Both groups of subjects experienced a similar amount of reflex inhibition by the end of the fatiguing protocol, although the endurance time was twice as long for the endurance-trained subjects. The endurance-trained subjects showed a greater reduction in H-reflex amplitude early in the fatiguing protocol compared to the sedentary subjects. These experiments have demonstrated that the neuromuscular processes associated with fatigue-related reflex inhibition must be multi-faceted and cannot be explained solely by small-diameter afferents responding to the byproducts of muscle contraction.