Background: Leg length discrepancy (LLD) following total hip arthroplasty (THA) is a leading cause of patient dissatisfaction. However, no reports have described the influence of lower limb alignment on LLD after THA. In the present study, we firstly investigated the change in lower limb alignment after THA. Secondly, we determined the influence of lower limb alignment on LLD after THA. Thirdly, we evaluated the influence of LLD in the entire lower leg on the clinical outcomes after THA. Methods: We followed up with 54 unilateral hip osteoarthritis (OA) patients 1 year after THA. For the radiological assessment of LLD and lower limb alignment, we obtained anteroposterior radiographs of the pelvis and both lower legs in entirety in a standing position before and 1 year after THA. The Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36) were also obtained to assess the clinical outcome. Resuts: The alignment of the affected leg, which was more valgus than the unaffected leg before THA, tended toward varus after THA, and the discrepancy between the lower limb alignments on both sides decreased. However, the alignment discrepancies that remained after THA influenced the LLD measured on the radiograph of the entire lower leg, and this LLD influenced the clinical outcome as measured by the HHS and the WOMAC score. Conclusions: LLD in the entire lower leg should be corrected for a better clinical outcome after THA.

CINCA/NOMID is an autoinflammatory disorder characterized by the triad of neonatal onset of cutaneous symptoms, chronic meningitis, and recurrent fever and it presents with distinctive osteoarthropathy, synovitis mainly of the large joints and overgrowth of epimetaphyseal cartilage, particularly of the long bones. The cartilage overgrowth eventually causes osseous overgrowth and deformity that persists beyond skeletal maturity and leads to limb length discrepancy, joint contracture, and early degenerative arthropathy. Autoinflammation in CAPS/NOMID has been proven to derive from excessive release of interleukin-1 (IL-1). It has been well documented that the IL-1 receptor antagonist anakinra (Kineret(R)) helps mitigate systemic inflammation in the disorder. However, a general consensus has not been reached on its beneficial effect on osteoarthropathy. The case of a girl with CINCA/NOMID syndrome who showed dramatic improvement of osteoarthropathy after anakinra treatment is reported. A 4-year-old girl suffered at the age of 10 months from a generalized urticarial skin lesion with recurrent episodes of fever and growth disorder. Blood examination revealed persistent massive neutrophilia, anemia and intense acute phase response. She manifested knee joint swelling with limited ROM when she was 20 months old and was diagnosed as being CINCA/NOMID based on characteristic findings of radiograph despite negative CIAS1 mutation. Radiological examination demonstrated metaphyseal fraying and cupping and widening of the growth plate in the distal femur. MR imaging showed mottled gadolinium enhancement at the chondrosseous junction. Neither significant joint effusion nor synovitis was identified. At 2 years and 7 months of age, anakinra, 2 mg/kg/day given by regular daily subcutaneous injections, was started. A few days after the initiation of the treatment, her clinical symptoms and laboratory findings of active inflammation were promptly alleviated. She was not able to walk unaided prior to the treatment, but she walked independently 1 month after the treatment. Follow-up radiographs and MR imaging showed that growth plate widening and gadolinium enhancement at the chondrosseous junction were less conspicuous. Furthermore, longitudinal growth of the femur and tibia was identified during 20 months of observation.

The gluteus medius (GMED) affects hip function as an abductor. We evaluated muscle volume and degeneration of the GMED by using CT-based analysis and assessed factors that affect hip abductor strength in patients with unilateral hip osteoarthritis (OA). We examined clinical and imaging findings associated with hip abductor strength in consecutive 50 patients with unilateral hip OA. Hip abductor muscle strength and Harris hip score (HHS) were assessed. Leg length discrepancy (LLD) and femoral offset were assessed using X-ray; CT assessment was employed for volumetric and qualitative GMED analysis. Volumetric analysis involved measurement of cross sectional area (CSA) and three-dimensional (3D) muscle volume. CT density was measured for the qualitative assessment of GMED degeneration with or without adjustment using a bone mineral reference phantom. Hip abductor muscle strength on the affected side was significantly lower than that on the contralateral healthy side and positively correlated with overall score and score for limping of gait of HHS, demonstrating the importance of hip abductor strength for normal hip function. A significant correlation was found between CSA and 3D muscle volume, unadjusted CT density and adjusted CT density, and hip abductor strength and these CT measurements. Multiple linear regression analysis demonstrated that 3D muscle volume, adjusted CT density, and LLD are independent factors affecting hip abduction. 3D measurement of muscle volume and adjusted CT density more accurately reflect quantity and the GMED quality than do conventional assessments. Increase in muscle volume, recovery of muscle degeneration, and correction of LLD are important for improving limping in patients with hip OA.

Markers of coagulation and fibrinolysis, such as soluble fibrin (SF), D-dimer, and plasminogen activator inhibitor 1 (PAI-1), have been developed in order to determine thrombotic tendency. We investigated whether these markers could be used to diagnose venous thromboembolism (VTE) in the early phase after primary total hip arthroplasty (THA). This prospective study involved 2 groups: an intermittent pneumatic compression (IPC) group (67 patients who underwent IPC only as prophylaxis for VTE) and a fondaparinux (FPX) group (103 patients who received IPC and FPX postoperatively). Plasma levels of SF and PAI-1 were measured on postoperative day 1. To diagnose postoperative VTE, multi-detector row computed tomography (MDCT) and duplex ultrasonography (US) were performed on postoperative day 7. VTE was detected postoperatively in 17 cases in the IPC group (25%) and in 8 cases in the FPX group (6%). In the IPC group, plasma levels of SF and PAI-1 were higher in patients with VTE (p < 0.01) than in those without VTE. On the other hand, in the FPX group there were no differences in the levels of SF or PAI-1 measured before administration of FPX on postoperative day 1. The diagnostic criterion of an increase in SF or PAI-1 above the cutoff level (19.8 µg/mL and 53.5 ng/mL, respectively) provided a sensitivity of 100% and a specificity of 67% in the IPC group. In addition, when this criterion was applied to FPX patients, 7 of the 8 patients with VTE met the criterion, and there was a negative agreement rate of 48/49. Screening using the cutoff levels of SF and PAI-1 may be useful and shows high sensitivity in predicting postoperative VTE in the early phase after THA.