Bone remodeling and cortical thinning distal to the femoral stem: a retrospective review.

INTRODUCTION: There is a paucity of information on the bone remodeling that occurs distal to the femoral stem following total hip arthroplasty as most previous studies have focused on proximal changes. In this study, we report the cortical thinning that occur distal to the femoral stem after primary total hip arthroplasty. METHODS: A retrospective review was performed at one institution over a 5-year period. 156 primary total hip arthroplasty procedures were included. The Cortical Thickness Index (CTI) was measured on both operative and non-operative hips at 1 cm, 3 cm and 5 cm below the prosthetic stem tip on anteroposterior radiographic images pre-operatively as well as at 6 months, 12 months and 24 months post-operatively. The difference in average CTI was measured using paired t-tests. RESULTS: There were statistically significant decreases in CTI distal to the femoral stem at 12 months and 24 months (-1.3% and -2.8%, respectively). Greater losses were seen in female patients, patients older than 75, and patients with BMI less than 35 at 6 months postoperative. There were no differences in CTI at any time point on the non-operative side. CONCLUSION: The current study demonstrates that patients undergo bone loss as measured by CTI distal to the stem in the first 2 years following total hip arthroplasty. Comparison to the contralateral non-operative side confirms that this change is greater than expected for the natural aging process. A greater understanding of these changes will help optimize post-operative management and direct future innovations in implant design.

Frequency of orthopedic manifestations in COVID-19 patients.

OBJECTIVES: The effects of the novel coronavirus on the musculoskeletal system have been reported with wide variability. The purpose of this study was to determine the prevalence of musculoskeletal symptoms and if these correlated with other patient characteristics. METHODS: This was a retrospective review of 685 admitted patients who were found to be positive for COVID-19 during their admission. Based on a standard COVID-19 questionnaire, we recorded complaints of new onset myalgias, joint pain, back pain, and muscle weakness and performed a chart review for all existing comorbidities. Statistical analyses were performed to determine the association between various comorbidities and orthopedic manifestations of COVID-19 patients. RESULTS: Of the 685 patients who tested positive for COVID-19, 186 patients presented with at least one orthopedic manifestation (27.1%). Patients that experienced orthopedic manifestations were significantly younger at 53.7 years of age compared to 58.1 years of age (p = 0.003) with a significantly higher BMI (body mass index) at 32.6 versus 30.0 (p = 0.022). Patients that had diabetes or were obese had significantly higher rates of orthopedic manifestations while those that had heart or lung disease had significantly fewer. CONCLUSION: Obese and diabetic patients had significantly higher rates of orthopedic symptoms during COVID-19 infection. Further studies need to be carried out in these populations to determine if these comorbidities during infection have an effect on the musculoskeletal system in the perioperative setting and after recovery from infection.