Aspen Miller

Hip dysplasia is currently diagnosed with two-dimensional radiographic measurements that may not adequately describe the aetiology of pain and dysfunction associated with dysplastic deformity and future osteoarthritis progression. This study aimed to assess how accurately two-dimensional radiographic measurements represent the three-dimensional mechanical joint environment. Spearman ρ correlation was used to determine associations between radiographic measurements of hip dysplasia made on pre-operative and 6-month post-operative standing AP pelvis radiographs, and hip contact stress calculated based on pre- and post-operative pelvis CT scans for a series of 100 patients (125 dysplastic hips) treated with periacetabular osteotomy using discrete element analysis. Only moderate correlations were observed between radiographic measurements and contact mechanics. Pre-operative lateral centre edge angle of Wiberg had the highest, though moderate, correlation with mean cumulative contact stress-time exposure (ρ = −0.5112, P < .0001). Tönnis angle (ρ = 0.4898, P < .0001) and extrusion index (ρ = 0.4579, P < .0001) also had moderate correlations with pre-operative mean cumulative contact stress-time exposure. Only weak correlations were found post-operatively and when comparing change in radiographic measurements to computational contact mechanics metrics before and after surgery. These findings indicate the mechanical environment of the hip joint is more complex than simple radiographic measurements that quantify coverage of the femoral head by the acetabulum. Evaluation of three-dimensional contact mechanics in dysplastic hips should be used in combination with two-dimensional radiographic evaluation for guiding clinical care for patients with hip dysplasia.

Hip dysplasia causes pathologic joint mechanics and can produce hip instability, leading to progressive joint degeneration and osteoarthritis. Weight-bearing computed tomography (WBCT) is an emerging technology that may enable quantification of femoral–acetabular displacement as an objective indicator of instability. To evaluate this potential, 10 patients indicated for periacetabular osteotomy to treat hip dysplasia and 10 healthy controls underwent two WBCT protocols. Participants were scanned in a neutral stance [weight-bearing (WB)] and again with the hip stressed in maximal external rotation (WB-stress), a position hypothesized to reproduce anterior instability. Clinical, nonweight-bearing computed tomography (CT) scans were available for patients with hip dysplasia. Congruency of the femoroacetabular joint space and position of the femoral head in the acetabulum were quantified via multiple 2D manual measurements and automated 3D measurements. There were no 2D measurements found to differ between the WB and WB-stress scans in either dysplastic (P = .742–1.000) or control (P = .203–1.000) hips. 3D translation of the femoral head center from WB to WB-stress averaged 1.3 ± 0.6 mm in the control hips, compared to 0.9 ± 0.4 mm in the dysplastic hips (P = .096). 3D joint space width (JSW) was determined for both the control and dysplastic hips, with greater JSW found in control hips for both the WB (P = .049) and WB-stress (P = .003) scans. WBCT has the potential to better capture subtle femoral–acetabular displacement derived from both automated 3D and manual 2D measurements in static instability-prone joint orientations.

Background: Femoral fragility fractures in older adults can result in devastating loss of physical function and independence. Skeletal muscle atrophy likely contributes to disability. The purpose of this study was to characterize the change in skeletal muscle mass, investigate the relationship with malnutrition and physical function, and identify risk factors for skeletal muscle loss. Methods: Adults ≥65 years of age who were treated with operative fixation of an isolated femoral fragility fracture were enrolled in this multicenter, prospective observational study. Skeletal muscle mass was assessed within 72 hours of admission using multifrequency bioelectrical impedance analysis, which was repeated at 6 weeks, 3 months, and 6 months. Sarcopenia was defined by sex-specific cutoffs for the appendicular skeletal muscle mass index. The Mini Nutritional Assessment was used to measure nutritional status at the time of injury. Physical function was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function domain. Linear mixed models were used to evaluate changes in skeletal muscle mass and PROMIS Physical Function scores over time and to evaluate factors associated with skeletal muscle mass changes. Results: Ninety participants (74% female) with a mean age of 77.6 ± 9.0 years were enrolled. At the time of injury, 30 (33%) were sarcopenic and 44 (49%) were at risk for malnutrition or had malnutrition. Older age was associated with lower skeletal muscle mass (age of ≥75 versus <75 years: least squares mean [and standard error], −3.3 ± 1.6 kg; p = 0.042). From the time of injury to 6 weeks, participants lost an average of 2.4 kg (9%) of skeletal muscle mass (95% confidence interval [CI] = ‒3.0 to ‒1.8 kg; p < 0.001). This early loss did not recover by 6 months (1.8 kg persistent loss compared with baseline [95% CI = ‒2.5 to ‒1.1 kg]; p < 0.001). Participants with normal nutritional status lost more skeletal muscle mass from baseline to 6 weeks after injury compared with those with malnutrition (1.3 kg more loss [standard error, 0.6 kg]; p = 0.036). A 1-kg decrease in skeletal muscle mass was associated with an 8-point decrease in the PROMIS Physical Function (model parameter estimate, 0.12 [standard error, 0.04]; p = 0.002). Conclusions: We found that older adults with femoral fragility fractures lost substantial skeletal muscle mass and physical function. Participants with adequate baseline nutrition actually lost more muscle mass than those who were malnourished, indicating that future investigations of interventions to prevent muscle loss should focus on older adults regardless of nutritional status. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Periacetabular osteotomy (PAO) is a well-established surgical treatment for hip dysplasia. Few studies report risk factors for the development of superior ramus osteotomy non-union. The purpose of this investigation was to document the incidence and risk factors for this complication. We identified 316 consecutive hips that underwent PAO for symptomatic acetabular dysplasia with a minimum 1-year radiographic follow-up. We developed and validated a technique to measure the superior ramus osteotomy location on anterior-posterior (AP) pelvis radiographs and computed tomography. Logistic regression with generalized estimating equations was used to evaluate the relationships between odds of non-union and potential demographic and radiographic predictor variables in univariate and multivariate analyses. Twenty-nine (9.2%) hips developed superior ramus non-union. Age {median [interquartile range (IQR)] 23 years (18–35) healed versus 35 years (26–40) non-united, P = 0.001}, pre-operative lateral center-edge angle (LCEA) [16° (11–20) healed versus 10° (6–13) non-united, P < 0.001] and the distance from the superior ramus osteotomy to the ilioishial line [15.8 mm (13.2–18.7) healed versus 18.1 mm (16.2–20.5) non-united, P < 0.001] varied significantly between groups. Using multivariate analysis, moderate-to-severe dysplasia [LCEA < 15°, odds ratio (OR) 5.95, standard error (SE) 3.32, 95% confidence interval (CI) 1.99–17.79, P = 0.001], increased age (5-year increase, OR 1.29, SE 3.32, 95% CI 1.105–1.60, P-value = 0.018) and distance from the ilioishial line (3-mm increase, OR 1.67, SE 0.22, 95% CI 1.29–2.18, P < 0.001) were at increased risk of developing non-union. Superior ramus osteotomy non-union is common after PAO. Older age, moderate-to-severe dysplasia, and more medial osteotomy location were independent risk factors for non-union. Consideration should be made in high-risk patients for a more lateral superior ramus osteotomy and adjuvant medical and surgical interventions.

Background: Postoperative complications and substantial loss of physical function are common after musculoskeletal trauma. We conducted a prospective randomized controlled trial to assess the impact of conditionally essential amino acid (CEAA) supplementation on complications and skeletal muscle mass in adults after operative fixation of acute fractures. Methods: Adults who sustained pelvic and extremity fractures that were indicated for operative fixation at a level-I trauma center were enrolled. The subjects were stratified based on injury characteristics (open fractures and/or polytrauma, fragility fractures, isolated injuries) and randomized to standard nutrition (control group) or oral CEAA supplementation twice daily for 2 weeks. Body composition (fat-free mass [FFM]) was measured at baseline and at 6 and 12 weeks postoperatively. Complications were prospectively collected. An intention-to-treat analysis was performed. The relative risk (RR) of complications for the control group relative to the CEAA group was determined, and linear mixed-effects models were used to model the relationship between CEAA supplementation and changes in FFM. Results: Four hundred subjects (control group: 200; CEAA group: 200) were enrolled. The CEAA group had significantly lower overall complications than the control group (30.5% vs. 43.8%; adjusted RR = 0.71; 95% confidence interval [CI] = 0.55 to 0.92; p = 0.008). The FFM decreased significantly at 6 weeks in the control subjects (–0.9 kg, p = 0.0205), whereas the FFM was maintained at 6 weeks in the CEAA subjects (−0.33 kg, p = 0.3606). This difference in FFM was not seen at subsequent time points. Conclusions: Our results indicate that CEAA supplementation has a protective effect against common complications and early skeletal muscle wasting after operative fixation of extremity and pelvic fractures. Given the potential benefits of this inexpensive, low-risk intervention, multicenter prospective studies in focused trauma populations are warranted. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.