A Novel Assessment of Braking Reaction Time Following THA Using a New Fully Interactive Driving Simulator.

BACKGROUND: After total hip replacement surgery, patients are eager to resume the activities of daily life, particularly driving. Most surgeons recommend waiting 6 weeks after surgery to resume driving; however, there is no evidence to indicate that patients cannot resume driving earlier. QUESTIONS/PURPOSES: Our purpose was to evaluate when in the recovery period following THA that patients regain or improve upon their preoperative braking reaction time, allowing them to safely resume driving. METHODS: We measured and compared pre- and postoperative braking reaction times of 90 patients from 3 different surgeons using a Fully Interactive Driving Simulator (Simulator Systems International, Tulsa, OK). We defined a return to safe braking reaction time as a return to a time value that is either equal to or less than the preoperative braking reaction time. RESULTS: Patients tested at 2 and 3 weeks after surgery had slower braking reaction times than preoperative times by an average of 0.069 and 0.009 s, respectively. At 4 weeks after surgery, however, patients improved their reaction times by 0.035 s (p = 0.0398). In addition, at 2, 3, and 4 weeks postoperatively, the results also demonstrated that patient less than 70 years of age recovered faster. CONCLUSIONS: Based upon the results of this study, most patients should be allowed to return to driving 4 weeks following minimally invasive primary total hip arthroplasty.

Weight changes after total hip or knee arthroplasty: prevalence, predictors, and effects on outcomes.

BACKGROUND: Conflicting evidence exists with regard to weight loss after total hip arthroplasty or total knee arthroplasty. The purposes of this study were to determine whether patients lose weight after total hip arthroplasty or total knee arthroplasty, whether there are predictors of weight change after total hip arthroplasty or total knee arthroplasty, and whether weight changes after total hip arthroplasty or total knee arthroplasty affect patient-reported outcomes. METHODS: Using our institutional registry, we evaluated the two-year change in self-reported body mass indices for all patients who underwent elective, unilateral total hip arthroplasty or total knee arthroplasty for osteoarthritis. A 5% change in body mass index was considered clinically meaningful. Patient-reported outcomes were compared between patients who underwent total hip arthroplasty and those who underwent total knee arthroplasty and between obesity classes, on the basis of whether patients gained, lost, or maintained weight. RESULTS: We reviewed 3893 total hip arthroplasties and 3036 total knee arthroplasties. Of the patients who underwent total joint arthroplasty, 73% (2850 patients) in the total hip arthroplasty group and 69% (2090 patients) in the total knee arthroplasty group demonstrated no change in body mass index. Patients who underwent total knee arthroplasty were more likely to lose weight than patients who underwent total hip arthroplasty. Increasing preoperative obesity correlated with a greater likelihood of weight loss. Patients who underwent total knee arthroplasty and lost weight demonstrated better clinical outcome scores, but weight gain in general was associated with inferior clinical outcomes. Greater body mass index, total knee arthroplasty, and female sex were significant predictors of weight loss (p < 0.05). Better preoperative functional status was significantly associated with a lower likelihood of weight gain (p < 0.05). CONCLUSIONS: Most patients maintained their body mass index after total hip arthroplasty or total knee arthroplasty. Female patients, patients with higher preoperative body mass index, and those who underwent total knee arthroplasty were more likely to lose weight after surgery. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prophylaxis for thromboembolic disease and evaluation for thrombophilia.

Patients treated with total hip or knee arthroplasty are at risk for venous thromboembolic disease. Laboratory evaluation of thrombophilia can help to better identify patients at higher risk for venous thromboembolic disease, and newer methods that test for genetic factors continue to evolve; however, more research is needed to justify routine testing for thrombophilia. Research studies have yielded differing results in determining the most appropriate prophylactic regimen. Both pharmaceutical and mechanical treatments are commonly used for prophylaxis. New pharmacologic prophylaxes include the Xa inhibitor rivaroxaban and the thrombin inhibitor dabigatran etexilate. The newest mechanical device used to prevent venous thromboembolism is a miniature, mobile, battery-operated pneumatic system called Continuous Enhanced Circulation Therapy. The American College of Chest Physicians guidelines and the American Academy of Orthopaedic Surgeons clinical guideline were reviewed to directly compare specific agents and balance the risks of venous thromboembolism. Future studies for venous thromboembolic prophylaxis will continue to evaluate new oral agents, improved pneumatic compression devices, and improved methods to decrease bleeding in the immediate postoperative period.

Are bilateral total joint arthroplasty patients at a higher risk of developing pulmonary embolism following total hip and knee surgery?

Despite developments in prophylactic methods, venous thromboembolism (VTE) continues to be a serious complication following total joint arthroplasty. The new AAOS/ACCP guidelines on preventing pulmonary embolism (PE) after total hip/knee arthroplasty (THA/TKA) do not make specific recommendations for bilateral vs. unilateral procedures. In-patient PE rates were examined for patients undergoing unilateral or simultaneous bilateral TKA/THA at our institution in 2011. Of the 7,437 THA/TKA surgeries completed at our institution in 2011, 36 patients suffered from PE (0.48%). The rate of PE for unilateral TKA was 0.61% vs. 1.87% for bilateral (P < 0.001) and for unilateral THA was 0.17% vs. 0.52% for bilateral THA. Despite patients being screened before being cleared to undergo bilateral THA/TKA, they remain at higher risk for VTE.