What preoperative factors predict postoperative sitting pelvic position one year following total hip arthroplasty?

AIMS: The aims of this study were to measure sagittal standing and sitting lumbar-pelvic-femoral alignment in patients before and following total hip arthroplasty (THA), and to consider what preoperative factors may influence a change in postoperative pelvic position. PATIENTS AND METHODS: A total of 161 patients were considered for inclusion. Patients had a mean age of the remaining 61 years (sd 11) with a mean body mass index (BMI) of 28 kg/m2 (sd 6). Of the 161 patients, 82 were male (51%). We excluded 17 patients (11%) with spinal conditions known to affect lumbar mobility as well as the rotational axis of the spine. Standing and sitting spine-to-lower-limb radiographs were taken of the remaining 144 patients before and one year following THA. Spinopelvic alignment measurements, including sacral slope, lumbar lordosis, and pelvic incidence, were measured. These angles were used to calculate lumbar spine flexion and femoroacetabular hip flexion from a standing to sitting position. A radiographic scoring system was used to identify those patients in the series who had lumbar degenerative disc disease (DDD) and compare spinopelvic parameters between those patients with DDD (n = 38) and those who did not (n = 106). RESULTS: Following THA, patients sat with more anterior pelvic tilt (mean increased sacral slope 18° preoperatively versus 23° postoperatively; p = 0.001) and more lumbar lordosis (mean 28° preoperatively versus 35° postoperatively; p = 0.001). Preoperative change in sacral slope from standing to sitting (p = 0.03) and the absence of DDD (p = 0.001) correlated to an increased change in postoperative sitting pelvic alignment. CONCLUSION: Sitting lumbar-pelvic-femoral alignment following THA may be driven by hip arthritis and/or spinal deformity. Patients with DDD and fixed spinopelvic alignment have a predictable pelvic position one year following THA. Patients with normal spines have less predictable postoperative pelvic position, which is likely to be driven by hip stiffness. Cite this article: Bone Joint J 2018;100-B:1289-96.

Molecular carrier testing for the fragile X syndrome: Issues for genetic counselors.

Molecular analysis of the fragile X (FMR-1) gene identifies female fragile X carriers, but appropriate genetic counseling can only be provided if the limitations of the testing methods are understood. Molecular analysis of this gene is achieved with both the polymerase chain reaction (PCR) and Southern blot techniques. PCR is faster and can determine the actual number of CGG repeats, which modifies genetic counseling substantially. However, for a sizeable percentage of women, PCR alone is not conclusive, and Southern analysis is necessary to complete the study. While this procedure takes longer, it is usually conclusive. Women who present for genetic counseling and carrier testing in the second trimester of pregnancy need this information quickly, and for them the turn-around time is paramount. It is critical that genetic counselors understand these methods so that they can educate their clients and facilitate appropriate follow-up.

Magnetic resonance imaging of biological specimens by electron paramagnetic resonance of nitroxide spin labels.

Electron paramagnetic resonance imaging was demonstrated on two plant species, Apium graveolens and Coleus blumei. This was accomplished by soaking stems of these plants in the paramagnetic nitroxide imaging agent 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The experiments were accomplished at L-band frequency (1.4 to 1.9 gigahertz) with single-turn, flat-loop surface coils. One-dimensional imaging spectra were diagnostic of capillary structure and long-term stability.