Introduction

Total hip arthroplasty (THA) is a physically demanding procedure where the surgeon is subject to fatigue with increased energy expenditure comparable to exercise[1]. Robotic technologies have been introduced into operating rooms to assist surgeons with ergonomically challenging tasks and to reduce overall physical stress and fatigue[2]. Greater exposure to robotic assisted training may create efficiencies that may reduce energy expenditure[3]. The purpose of this study was to assess surgeon energy expenditure during THA and perceived mental and physical demand.

Summary

There is tremendous variability amongst surgeons' ability to reference anatomic landmarks. This may suggest the necessity of other objective methods in determining femoral alignment and rotation.

Introduction: It is generally agreed that the function of the knee after total knee arthroplasty needs to be improved to meet the expectations of younger and more active patients. However, little objective information consists to quantify the frequency and importance of activities that place increased biomechanical demand on the knee. This study was performed to asses which specific “high-demand” activities are actually performed by patients after knee replacement, and which activities are of greatest personal importance to the patient.

Methods: An initial group of 243 patients (47% male; 53% female, average age: 70 years; range: (45–91 yrs)) were enrolled in this study with Institutional approval. All were at least 1 year post knee replacement and resided in the Houston area. All participants completed a validated, self-administered knee function questionnaire consisting of 55 scaled multiple choice questions regarding each respondent’s physical activities, limitations, and level of importance for those activities. Participants were also asked to assess the personal importance of each activity and the severity of any symptoms experienced when each activity was performed. An expanded version of the Knee Function Questionnaire was completed by a second group of 101 patients from 5 centres in the United States and Canada. This instrument addressed 120 physical, vocational and recreational activities involving the knee. Fifty-four of these activities were considered “highly demanding” and were drawn from a wide variety of water and team sports, martial arts, running/biking, exercise, weight-lifting and fitness training.

Results: The initial study demonstrated that TKR patients participate in a wide range of “high demand” activities. Most commonly, activities requiring increased knee flexion were gardening (58% participation), kneeling (64%), and squatting (39%). Moderate to severe difficulty was reported by 39% (squatting) to 64% (kneeling) of respondents performing these activities. The most common activity which placed increased loads on the affected joint was carrying loaded shopping bags (47% participation), which provoked Significant symptoms in 23% of patients. The expanded nation-wide study showed that after TKR, few patients actually perform high impact competitive sports although many patients perform individual exercise routines which potentially place Significant demands on the knee. The most common of these “high demand” activities were still squatting and kneeling, but also included participation in gym and exercise activities, typically leg extensions (59%), leg curls (35%) and leg press exercises (33%).

Conclusions:

Kneeling and squatting are the most common “high-demand” activities actually performed on a routine basis by patients after TKR

Introduction: Metal-on-metal (MOM) hip resurfacing releases ions locally and into the systemic circulation, raising concern for potential long term complications of elevated trace metals. This study was designed to monitor serum cobalt (Co) and chromium (Cr) levels in patients after MOM resurfacing hip arthroplasty with the Cormet 2000 prosthesis and to compare detected levels with those previously reported for hip resurfacing prostheses.

Methods: We prospectively followed patients receiving the Cormet 2000 device. Serum samples were collected at 6 months, 1, 2, and 3 years following surgery. Pre-operative controls were obtained from subjects without implants. Serum Co/Cr levels were determined using high-resolution inductively coupled plasma mass spectrometry. ANOVA was used to compare ion levels in each group. Statistical significance was set at p< 0.05.

Results: 40 subjects (25 male) were followed. Average age was 51 years (33.7–66.1). Median preoperative Co/ Cr levels were 0.27 microg/L (0.087–0.601) and 0.19 (0.014–0.576), respectively. Co/Cr levels were significantly increased at all time points when compared to preoperative levels (p< 0.001). Peak Co and Cr levels were observed at 1 year (3.26 and 4.42, respectively). At three years, the median Co and Cr levels had dropped to 2.08 and 3.55, respectively, but this was not statistically significant.

Conclusion: Elevated serum Co/Cr levels were observed at all time points following implantation. Continued elevations at three years were observed; however, the levels appear to be trending down suggestive of a “wear-in” period. Long term elevations of Co/Cr levels are concerning and will require additional studies to assess long term health risks of these levels in this population.