[The standard implantation of a total hip prosthesis via two incisions (the Yale Technique)]

Rehabilitation of gait in patients after total hip arthroplasty: Comparison of the minimal invasive Yale 2-incision technique and the conventional lateral approach

The minimal invasive anterolateral Yale 2-incision approach for total hip arthroplasty aims minimizing damage to the muscles for faster recovery of function. Therefore the hypothesis was investigated, that during the rehabilitation process the Yale approach shows a faster return to natural gait than a conventional lateral approach. Nineteen patients had the Yale, 16 the conventional Bauer approach. Instrumented gait analysis was performed 3 days, 3 and 12 month post operatively. Velocity, cadence, step length, weight bearing, thorax lean, Trendelenburg limp, hip abduction moments, and hip muscle activation times were evaluated. Three days post-surgery a significantly greater loading of the treated limb and increased hip abduction moment were observed in the Yale group. In addition, the Yale group showed its greatest improvement in walking speed and step length between at 3 days and 3 months, whereas the conventional group showed an additional significant gain between 3 and 12 month to reach a similar walking speed as the Yale group. For all hip muscles investigated, only muscle tensor fasciae latae in the conventional group showed a significant increase in activation time between 3 days and 3 months. This study showed significantly faster return to natural gait in the Yale compared to the conventional approach, which could be biomechanically related to less impairment of abductor muscles in the Yale approach.

[Nerve lesions after minimally invasive total hip arthroplasty]

Although there is no clear evidence, minimally invasive hip arthroplasty seems to be associated with slightly higher complication rates compared to standard procedures. Major nerve palsy is one of the least common but most distressing complications. The key for minimizing the incidence of nerve lesions is to analyze preoperative risk factors, accurate knowledge of the anatomy and minimally invasive techniques. Once clinical signs of nerve injury are evident, the first diagnostic steps are localization of the lesion and quantification of the damage pattern. Therefore, clinical assessment of the neurological deficits should be performed as soon as possible. Apart from rare cases of isolated transient conduction blockade or complete transection, the damage pattern is mostly combined. Thus, there can be evidence for dysfunction of nerve conduction (neuropraxia) and structural nerve damage (axonotmesis or neurotmesis) simultaneously. Because the earliest signs of denervation are detectable via electromyography after 1 week, it is not possible to make any reliable prognosis within the first days after nerve injury using electrophysiological methods. This review article should serve as a guideline for prevention, diagnostics and therapy of neural lesions in minimally invasive hip arthroplasty.