Restoration of hip architecture with bipolar hemiarthroplasty in the elderly: does it affect early functional outcome?

INTRODUCTION: Reconstruction of the anatomic architecture correlates with functional outcome in patients receiving elective total hip arthroplasty. In theory similar rules should apply for bipolar hemiarthroplasty in femoral neck fractures. The influence of anatomic restoration after bipolar hemiarthroplasty on short-term clinical and functional outcome is explored in this study. PATIENTS AND METHODS: Patients receiving bipolar hemiarthroplasty for intracapsular femoral neck fractures between 2010 and 2012 were included into a retrospective cohort study. Radiologic and functional outcome parameters were recorded during the acute care phase and geriatric rehabilitation. Postoperative mobilization data were recorded and co-morbidities documented for each case. Outcome parameters were obtained during geriatric rehabilitation: Barthel index, Tinetti score, Timed up and go test, Mini-Mental State Examination. The FO-ratio (ratio of femoral offset to the body weight lever arm), HC-ratio (ratio of the height of the hip center to the pelvic height) and the BWLA ratio (ratio of the body weight lever arm to the pelvic height) were obtained from postoperative radiographs. RESULTS: A total of 193 patients with a median age of 84 (IQR = 78-94, 72% female) were analyzed. The in-hospital mortality rate was 5.7%. There was a high proportion of patients with prior co-morbidities (96% with at least one co-morbidity). During rehabilitation the Barthel index improved significantly (p < 0.001) from 40 to 55. The median Tinetti score on rehabilitation discharge was 15.5 (IQR = 10-19.5). The patients significantly improved in the timed up and go test from a median of 22 to 19 s. A significant difference (p < 0.001) was found comparing the FO ratios of the operated vs. non-operated side. None of the radiographic measures, representing the reconstructed anatomic hip geometry, significantly influenced the clinical and geriatric outcome. CONCLUSIONS: Applying the short-term functional outcome scores used in this study, optimized anatomic restoration in hemiarthroplasty may not be a major influencing factor in a cohort of elder, multi-morbid patients.

SPP1 promoter polymorphisms: identification of the first modifier gene for pseudoxanthoma elasticum.

BACKGROUND: Progressive calcification and fragmentation of elastic fibers are characteristic hallmarks of pseudoxanthoma elasticum (PXE), which is caused by mutations in ABCC6 encoding multidrug resistance-associated protein 6 (MRP6). Because of the great clinical variability of PXE, secondary genetic risk factors are suspected to exist. We investigated whether SPP1 (secreted phosphoprotein 1; previously OPN, osteopontin) promoter polymorphisms are associated with PXE. METHODS: We screened an approximately 2-kb region spanning the theoretical promoter of the SPP1 gene for sequence variations by denaturing HPLC and direct sequencing in 93 PXE patients. Sequence variations with a prevalence >5% were genotyped in 93 age- and sex-matched healthy controls. Statistical and haplotype association analyses were performed using Fisher exact test, PHASE v2.1.1, and Haploview 3.2. RESULTS: Mutational screening revealed 9 different sequence variations. Three SPP1 promoter polymorphisms (c.-1748A>G, c.-155_156insG, and c.244_245insTG) were significantly more frequent in PXE patients than in 93 age- and sex-matched healthy controls (P(corrected) < 0.05 each). The odds ratios (95% CI) for PXE among carriers of the 3 alleles were, respectively, 2.16 (1.34-3.48), 2.41 (1.51-3.82), and 1.97 (1.23-3.15). Haplotype analysis of 6 SPP1 promoter polymorphisms revealed 1 haplotype to be significantly reduced among PXE patients (P(corrected) = 0.035, odds ratio 1.80, 95% CI 1.19-2.71). CONCLUSIONS: Polymorphisms in the SPP1 promoter are secondary genetic risk factors contributing to PXE susceptibility.

Role of serum fetuin-A, a major inhibitor of systemic calcification, in pseudoxanthoma elasticum.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is a hereditary disorder of the connective tissue affecting the skin, retina, and cardiovascular system and characterized by progressive calcification of abnormal and fragmented elastic fibers in the extracellular matrix. The aim of the present study was to investigate the association of fetuin-A, a major systemic inhibitor of calcification, with PXE. METHODS: Fetuin-A was measured by quantitative sandwich enzyme immunoassay in sera from 110 German patients with PXE, 53 unaffected first-degree family members, and 80 healthy blood donors. We determined the distribution of the fetuin-A polymorphisms c.742C>T (p.T248M) and c.766C>G (p.T256S) in these same 3 groups. The occurrences of the frequent ABCC6 gene mutations c.3421C>T (p.R1141X) and c.EX23_EX29del were also assessed. RESULTS: Serum fetuin-A concentrations in male and female PXE patients were lower than in unaffected first-degree relatives and controls [mean (SD) concentrations, 0.55 (0.11) g/L in patients; 0.70 (0.23) g/L in relatives; and 0.80 (0.23) g/L in controls (P <0.0001)]. Serum fetuin-A was higher in female PXE patients with cardiovascular involvement than in the corresponding male group (P <0.05). The fetuin-A polymorphism frequencies did not differ among PXE patients, family members, and blood donors. CONCLUSION: A deficiency of multidrug resistance-associated protein 6 leads to alteration of circulating substrates, e.g., inhibitors of calcification as fetuin-A, leading to progressive mineralization of elastic fibers in PXE.