Objectives. There are several reports clarifying successful results following open reduction using Ludloff’s medial approach for congenital (CDH) or developmental dislocation of the hip (DDH). This study aimed to reveal the long-term post-operative course until the period of hip-joint maturity after the conventional surgical treatments. Methods. A long-term follow-up beyond the age of hip-joint maturity was performed for 115 hips in 103 patients who underwent open reduction using Ludloff’s medial approach in our hospital. The mean age at surgery was 8.5 months (2 to 26) and the mean follow-up was 20.3 years (15 to 28). The radiological condition at full growth of the hip joint was evaluated by Severin’s classification. Results. All 115 hips successfully attained reduction after surgery; however, 74 hips (64.3%) required corrective surgery at a mean age of 2.6 years (one to six). According to Severin’s classification, 69 hips (60.0%) were classified as group I or II, which were considered to represent acceptable results. A total of 39 hips (33.9%) were group III and the remaining seven hips (6.1%) group IV. As to re-operation, 20 of 21 patients who underwent surgical reduction after 12 months of age required additional corrective surgeries during the growth period as the hip joint tended to subluxate gradually. Conclusion. Open reduction using Ludloff’s medial approach accomplished successful joint reduction for persistent CDH or DDH, but this surgical treatment was only appropriate before the ambulating stage. Cite this article: Bone Joint Res 2014;3:1–6

Aims. This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Methods. The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured. Results. The mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups. Conclusion. We demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH. Cite this article: Bone Joint Res 2021;10(10):629–638

Aims. Developmental dysplasia of the hip (DDH) is a complex musculoskeletal disease that occurs mostly in children. This study aimed to investigate the molecular changes in the hip joint capsule of patients with DDH. Methods. High-throughput sequencing was used to identify genes that were differentially expressed in hip joint capsules between healthy controls and DDH patients. Biological assays including cell cycle, viability, apoptosis, immunofluorescence, reverse transcription polymerase chain reaction (RT-PCR), and western blotting were performed to determine the roles of the differentially expressed genes in DDH pathology. Results. More than 1,000 genes were differentially expressed in hip joint capsules between healthy controls and DDH. Both gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that extracellular matrix (ECM) modifications, muscle system processes, and cell proliferation were markedly influenced by the differentially expressed genes. Expression of Collagen Type I Alpha 1 Chain (COL1A1), COL3A1, matrix metalloproteinase-1 (MMP1), MMP3, MMP9, and MMP13 was downregulated in DDH, with the loss of collagen fibres in the joint capsule. Expression of transforming growth factor beta 1 (TGF-β1) was downregulated, while that of TGF-β2, Mothers against decapentaplegic homolog 3 (SMAD3), and WNT11 were upregulated in DDH, and alpha smooth muscle actin (αSMA), a key myofibroblast marker, showed marginal increase. In vitro studies showed that fibroblast proliferation was suppressed in DDH, which was associated with cell cycle arrest in G0/G1 and G2/M phases. Cell cycle regulators including Cyclin B1 (CCNB1), Cyclin E2 (CCNE2), Cyclin A2 (CCNA2), Cyclin-dependent kinase 1 (CDK1), E2F1, cell division cycle 6 (CDC6), and CDC7 were downregulated in DDH. Conclusion. DDH is associated with the loss of collagen fibres and fibroblasts, which may cause loose joint capsule formation. However, the degree of differentiation of fibroblasts to myofibroblasts needs further study. Cite this article: Bone Joint Res 2021;10(9):558–570

Aims

Osteoporosis is common in total hip arthroplasty (THA) patients. It plays a substantial factor in the surgery’s outcome, and previous studies have revealed that pharmacological treatment for osteoporosis influences implant survival rate. The purpose of this study was to examine the prevalence of and treatment rates for osteoporosis prior to THA, and to explore differences in osteoporosis-related biomarkers between patients treated and untreated for osteoporosis.

Objectives

In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes.

Over recent years hip arthroscopic surgery has evolved into one of the most rapidly expanding fields in orthopaedic surgery. Complications are largely transient and incidences between 0.5% and 6.4% have been reported. However, major complications can and do occur. This article analyses the reported complications and makes recommendations based on the literature review and personal experience on how to minimise them.