Injury of the lateral femoral cutaneous nerve (LFCN) is one of the known complications after periacetabular osteotomy (PAO) using anterior approach. We previously reported that the incidence of LFCN injury was 48% at 1 year after PAO. However, there was no study examining the sequential changes of LFCN injury status. In this study, we performed a prospective over 3-year follow-up study as to the incidence of LFCN injury as well as its clinical outcomes.

This study included 40 consecutive hips in 40 patients (3 males and 37 females) who underwent PAO from May 2016 to July 2018. The mean age at surgery was 36.7 years (17 to 60). The mean observation period was 47.3 months (36 to 69). The incidence and severity of LFCN injury was evaluated, while clinical scores, including the Harris Hip Score (HHS), Short-Form 36 Health Survey (SF-36), and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), were also investigated.

At 3 years after PAO, LFCN injury was observed in 13 of 40 (33%) patients, in which 7 patients who had a symptom at 1 year have completely recovered. There was no significant difference in the HHS and SF-36 between patients with and without LFCN injury at 3 years. Regarding the JHEQ, a significant difference was recognized in the patient satisfaction and mental score between patients with and without LFCN injury, but there were no significant differences in the other clinical scores.

The incidence of LFCN injury gradually decreased to 33% at 3 years after CPO. LFCN injury did not influence the clinician-reported outcome, while it had a negative impact on patient satisfaction and mental score based on the patient-reported outcome.

Osteonecrosis of the femoral head (ONFH) is an ischemic disorder that causes bone and bone marrow necrosis. In spite of many studies, the primary cause of ischemia is still unknown. The purpose of this study is to identify the susceptibility genes in ONFH.

We performed a genome-wide association study (GWAS) in 1,602 ONFH cases and 60,000 controls. Stratified GWASs based on the 3 subgroups of ONFH (corticosteroids, alcohol, idiopathic) were also performed. We then evaluated the candidate gene in silico using public databases.

Two loci in 12q24.11–12 and 20q12 showed significant association with ONFH. A stratified analysis suggested that the 12q24 locus was associated with ONFH through the drinking capacity. In the 20q12 locus, LINC01370 was the only gene, which functions were related to the plausible biological pathway for the development of ONFH.

A novel ONFH locus was identified at chromosome 20q12, and LINC01370 was the best candidate gene in this locus.