Long-term performance of ceramic and metal femoral heads on conventional polyethylene in young and active patients: a matched-pair analysis.

BACKGROUND: Ceramic femoral heads produce less wear of the opposing polyethylene than do metal femoral heads in wear simulation studies. This is a matched-pair analysis of the wear of ceramic and metal femoral heads on conventional polyethylene in uncemented total hip replacements in young, active patients at a minimum of fifteen years of follow-up. METHODS: From June 1989 to May 1992, thirty-one matched pairs of alumina ceramic or cobalt-chromium metal femoral heads were identified. Patients were matched on the basis of age, sex, body weight, diagnosis, and activity level. The mean age was 55 ± 9 years (range, twenty-three to sixty-five years) at the time of surgery. All procedures were performed with a posterolateral surgical approach by a single surgeon using press-fit Ranawat-Bernstein femoral stems, Harris-Galante-II acetabular cups, GUR 4150 conventional polyethylene (sterilized in argon), and 28-mm-diameter femoral heads. Wear measurements were performed by two independent observers using the computer-assisted Roman software. RESULTS: The average duration of follow-up was 17 ± 1.7 years (range, fifteen to twenty years). The mean Hospital for Special Surgery hip scores (and standard deviation) in the ceramic and metal groups were 39 ± 4 and 40 ± 3 at the time of final follow-up. The University of California Los Angeles activity score at the time of the final follow-up was 6 ± 2 for both groups. The mean wear rates for the ceramic group and the metal group were 0.086 ± 0.05 mm/yr and 0.137 ± 0.05 mm/yr, respectively (p = 0.0015). There was one reoperation in the ceramic group because of distal femoral osteolysis. There were three failures in the metal group, requiring isolated liner exchange in two hips and revision of the acetabular component in one hip because of wear-induced osteolysis and/or loosening that caused symptoms. Five hips in the ceramic group and six hips in the metal group had radiographic evidence of acetabular or femoral osteolysis, but none were symptomatic. CONCLUSIONS: Ceramic femoral heads produced significantly less wear on conventional polyethylene liners at the time of long-term follow-up than did metal heads in this matched-pair analysis of young and active patients with uncemented fixation.

Pain management after total knee arthroplasty using a multimodal approach.

Improvements in pain management techniques over the past decade have had a significant impact on the outcomes of total knee arthroplasty. Of these techniques, multimodal approaches have shown potential. The purpose of this study was to compare the results of periarticular injection (PAI) to a combination of patient-controlled epidural analgesia and femoral nerve block (PCEA/FNB). Ninety patients undergoing primary unilateral total knee arthroplasty between June 2010 and March 2011 were randomized into 2 groups. The first group received the PCEA/FNB protocol, whereas the second group received the PAI. Mean patient age was 66.1 ± 8.7 years. All patients were operated on using a similar standard medial parapatellar approach, and all received preemptive analgesia and postoperative pain protocols. All patients were interviewed twice daily for the first 3 days postoperatively, once on day 7, and once in month 6. The 2 groups had similar readiness for discharge (PCEA/FNB group, 3.3 ± 1.2 days; PAI group, 3.2 ± 1.9 days). The results indicated no statistical difference between the 2 groups in 3 of 4 categories (rest in the morning, rest in the evening, and ambulation in the morning). Pain on ambulation was the only category that was statistically lower in the PCEA/FNB group than in the PAI group.Although the study demonstrates similar results between the 2 groups, PAI can play a major role in postoperative pain control in institutions that may not have appropriately trained individuals, equipment, and resources for PCEA/FNB. It also reduces many of the side effects and complications associated with regional anesthesia.

Post-operative guidelines following hip arthroscopy.

Rehabilitation following hip arthroscopy can vary significantly. Existing programs have been developed as a collaborative effort between physicians and rehabilitation specialists. The evolution of protocol advancement has relied upon feedback from patients, therapists and observable outcomes. Although reports of the first femoroacetabular impingement (FAI) surgeries were reported in the 1930's, it was not until recently that more structured, physiologically based guidelines have been developed and executed. Four phases have been developed in this guideline based on functional and healing milestones achieved which allow the patient to progress to the next level of activity. The goal of Phase I, the protective phase, is to progressively regain 75% of full range of motion (ROM) and normalize gait while respecting the healing process. The primary goal of Phase II is for the patient to gain function and independence in daily activities without discomfort. Rehabilitation goals include uncompensated step up/down on an 8 inch box, as well as, adequate pelvic control during low demand exercises. Phase III goals strive to accomplish pain free, non-compensated recreational activities and higher demand work functions. Manual muscle testing (MMT) grading of 5/5 should be achieved for all hip girdle musculature and an ability to dynamically control body weight in space. Phase IV requires the patient be independent with home and gym programs and be asymptomatic and pain free following workouts. Return to running may be commenced at the 12 week mark, but the proceeding requirements must be achieved. Athletes undergoing the procedure may have an accelerated timetable, based on the underlying pathology. Recognizing the patient's pre-operative health status and post-operative physical demands will direct both the program design and the program timetable.

Working memory overload: fronto-limbic interactions and effects on subsequent working memory function.

The human working memory system provides an experimentally useful model for examination of neural overload effects on subsequent functioning of the overloaded system. This study employed functional magnetic resonance imaging in conjunction with a parametric working memory task to characterize the behavioral and neural effects of cognitive overload on subsequent cognitive performance, with particular attention to cognitive-limbic interactions. Overloading the working memory system was associated with varying degrees of subsequent decline in performance accuracy and reduced activation of brain regions central to both task performance and suppression of negative affect. The degree of performance decline was independently predicted by three separate factors operating during the overload condition: the degree of task failure, the degree of amygdala activation, and the degree of inverse coupling between the amygdala and dorsolateral prefrontal cortex. These findings suggest that vulnerability to overload effects in cognitive functioning may be mediated by reduced amygdala suppression and subsequent amygdala-prefrontal interaction.