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Purpose: Rotational acetabular osteotomy is a type of pelvic osteotomy that involves rotation of the acetabular bone to improve the bony coverage of the femoral head for patients with acetabular dysplasia. Favourable post-operative long-term outcomes have been reported in previous studies. However, there is a paucity of published data regarding three-dimensional bony coverage. The present study investigated the three-dimensional bony coverage of the acetabulum covering the femoral head in hips before and after rotational acetabular osteotomy and in normal hips.Methods: The computed tomography data of 40 hip joints (12 joints before and after rotational acetabular osteotomy; 16 normal joints) were analyzed. The three-dimensional bony coverage of each joint was evaluated using original software.Results: The post-operative bony coverage improved significantly compared with pre-operative values. In particular, the anterolateral aspect of the acetabulum tended to be dysplastic in patients with acetabular dysplasia compared to those with normal hip joints. However, greater bony coverage at the anterolateral aspect was obtained after rotational acetabular osteotomy. Meanwhile, the results of the present study may indicate that the bony coverage in the anterior aspect may be excessive.Conclusion: Three-dimensional analysis indicated that rotational acetabular osteotomy achieved favorable bony coverage. Further investigations are necessary to determine the ideal bony coverage after rotational acetabular osteotomy. [ABSTRACT FROM AUTHOR]

ABSTRACT To reduce the production of wear particles and subsequent aseptic loosening, we created a human articular cartilage-mimicked surface for a highly cross-linked polyethylene liner, whose surface grafted layer consisted of a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine). Although our previous in vitro findings showed that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted particles were biologically inert and caused no subsequent bone resorptive responses, and poly(2-methacryloyloxyethyl phosphorylcholine) grafting markedly decreased wear in hip joint simulator tests, the clinical safety, and in vivo wear resistance of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners remained open to question. Therefore, in the present study, we evaluated clinical and radiographic outcomes of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners 5 years subsequent to total hip replacement in 68 consecutive patients. No reoperation was required for any reason, and no adverse events were associated with the implanted liners. The average Harris Hip Score increased from 38.6 preoperatively to 96.5 5 years postoperatively, and health-related quality of life, as indicated by the Short Form 36 Health Survey, improved. Radiographic analyses showed no periprosthetic osteolysis or implant migration. Between 1 and 5 years postoperatively, the mean steady-state wear rate was 0.002 mm/year, which represented a marked reduction relative to other highly cross-linked polyethylene liners, and appeared to be unaffected by patient-related or surgical factors. Although longer follow up is required, poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners improved mid-term clinical outcomes. The clinical safety and wear-resistance results are encouraging with respect to the improvement of long-term clinical outcomes with poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2007-2016, 2017. [ABSTRACT FROM AUTHOR]

Objective We aimed to assess the diagnostic utility of the linguistically validated Japanese version of the Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale ( LANSS-J) as a screening tool for neuropathic pain in the clinical setting. Methods Patients with neuropathic pain or nociceptive pain who were 20 to 85 years of age were included. Sensitivity and specificity using the original cutoff value of 12 were assessed to evaluate the diagnostic utility of the LANSS-J. Sensitivity and specificity with possible cutoff values were calculated, along with area under the receiver operating characteristic curve. We then evaluated agreement regarding assessment of the LANSS-J by two investigators. We used the intraclass correlation coefficient ( ICC) for the total score and Cohen's kappa coefficient for each item. Results Data for patients with neuropathic pain ( n = 30) and those with nociceptive pain ( n = 29) were analyzed. With a cutoff of 12, the sensitivity was 63.3% (19/30) and the specificity 93.1% (27/29). Sensitivity improved substantially with a cutoff of ≤ 11 (≥ 83.3%, 25/30). High specificity (93.1%, 27/29) was sustained with a cutoff of 9 to 12. The ICC for the total score was 0.85, indicating sufficient agreement. Kappa coefficients ranged from 0.68 to 0.84. Conclusions The LANSS-J is a valid screening tool for detecting neuropathic pain. Our results suggest that employing the original cutoff value provides high specificity, although a lower cutoff value of 10 or 11 (with its high specificity maintained) may be more beneficial when pain attributed to neuropathic mechanisms is suspected in Japanese patients. [ABSTRACT FROM AUTHOR]

ABSTRACT The use of larger femoral heads to prevent the dislocation of artificial hip joints has recently become more common. However, concerns about the subsequent use of thinner polyethylene liners and their effects on wear rate have arisen. Previously, we prepared and evaluated the biological and mechanical effects of a novel highly cross-linked polyethylene (CLPE) liner with a nanometer-scaled graft layer of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). Our findings showed that the PMPC-grafted particles were biologically inert and caused no subsequent bone resorptive responses and that the PMPC-grafting markedly decreased wear in a hip joint simulator. However, the metal or ceramic femoral heads used in this previous study had a diameter of 26 mm. Here, we investigated the wear-resistance of the PMPC-grafted CLPE liner with a 40-mm femoral head during 10 × 106 cycles of loading in the hip joint simulator. The results provide preliminary evidence that the grafting markedly decreased gravimetric wear rate and the volume of wear particles, even when coupled with larger femoral heads. Thus, we believe the PMPC-grafting will prolong artificial hip joint longevity both by preventing aseptic loosening and by improving the stability of articular surface. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1103-1110, 2015. [ABSTRACT FROM AUTHOR]

ABSTRACT To prevent periprosthetic osteolysis and subsequent aseptic loosening of artificial hip joints, we recently developed a novel acetabular highly cross-linked polyethylene (CLPE) liner with graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) on its surface. We investigated the wear resistance of the poly(MPC) (PMPC)-grafted CLPE liner during 20 million cycles in a hip joint simulator. We extended the simulator test of one liner to 70 million cycles to investigate the long-term durability of the grafting. Gravimetric, surface, and wear particle analyses revealed that PMPC grafting onto the CLPE liner surface markedly decreased the production of wear particles and showed that the effect of PMPC grafting was maintained through 70 million cycles. We believe that PMPC grafting can significantly improve the wear resistance of artificial hip joints. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:369-376, 2014. [ABSTRACT FROM AUTHOR]