Developmental dysplasia of the hip (DDH) is a spectrum of pathology that involves dysplasia of both the acetabulum and the femur. If left untreated, it can develop to hip pain and osteoarthritis, which eventually require total hip arthroplasty (THA). A broad array of anatomical abnormalities of the acetabulum and femur, plus the younger age of DDH patients make THA a great challenge. Meticulous operation planning with various options is one of the most important prerequisites of a successful THA. This review presents the current concepts of acetabular and femoral reconstruction in THA for DDH, including high hip center, acetabular bone deficiency, highly porous metal, correction of femoral anteversion, femoral shortening osteotomy, stem selection, among others.

Osteoarthritis is the most prevalent form of arthritis worldwide and is the major cause of pain and loss of function in elderly people. A signal of the fat mass and obesity-associated (FTO) gene had been reported in a genome-wide association study of osteoarthritis. The FTO polymorphism (rs8044769) might exert its effect on osteoarthritis through obesity, because it was reported as a body mass index-associated single-nucleotide polymorphism. And replication studies showed inconsistent results for this association. Our present study is to check the association of rs8044769 with osteoarthritis and body mass index in Chinese Han population. A case-control association study was conducted by using 890 osteoarthritis cases and 844 controls in Chinese Han population. rs8044769 was genotyped in all subjects. Allelic and genotypic frequencies were compared between osteoarthritis cases and control subjects. Associations between rs8044769 and body mass index, and body mass index and osteoarthritis were also assessed. No significant difference was detected in genotype or allele distribution between osteoarthritis cases and controls (P > 0.05). Stratification by gender and body mass index revealed negative association between rs8044769 and osteoarthritis. We did not find any solid association between rs8044769 and higher body mass index. Meanwhile, we demonstrated that higher body mass index (body mass index ≥ 25) was associated with osteoarthritis. Our present study suggested that rs8044769 was not associated with osteoarthritis susceptibility or higher body mass index, and higher body mass index was a risk factor for osteoarthritis in the Chinese Han population. We also proposed that stratification by clinical parameters was crucial to reduce false-positive result in OA association studies.

Background: Remplissage with Bankart repair (RMBR) is an arthroscopic procedure performed on <25% of Bankart lesions with off-track Hill-Sachs lesions (HSLs) that alters the insertion of the infraspinatus muscle into the humeral head. However, the effects of RMBR surgery on humeral head displacement due to changes in biomechanics and kinematics have not been fully elucidated. Purpose: To evaluate how the biomechanical and kinematic effects of the post-RMBR glenohumeral joint influence humeral head displacement using the finite element analysis (FEA) method. Study Design: Controlled laboratory study. Methods: Biomechanical and kinematic experiments were performed on 24 established finite element (FE) models, which included 12 normal glenohumeral joint models and 12 post-RMBR glenohumeral joint models at the abduction and external rotation (ABER) position. FEA was used to compute the total displacement of the humeral head during passive anteroinferior loading and active contraction of the infraspinatus muscle. Results: Under passive anteroinferior loading, the humeral heads showed less total anterior displacement after RMBR than did normal glenohumeral joints in the ABER position (1.94 ± 0.48 vs 5.19 ± 1.91 mm; P = .003). When the infraspinatus muscle was stimulated to contract, the humeral heads of post-RMBR glenohumeral joints exhibited greater total posterior displacement in the ABER position than did the normal glenohumeral joints (4.22 ± 0.23 vs 2.44 ± 0.56 mm; P < .001). Conclusion: Displacement of the humeral head is influenced by changes in the insertion of the infraspinatus tendon after RMBR surgery, which consequently affects the lever arm and torque generated by the infraspinatus muscle on the humeral head. Clinical Relevance: The FEA results confirmed that a change in the insertion of the infraspinatus tendon alters the lever arm and torque produced by the infraspinatus muscle on the humeral head. This leads to changes in the displacement of the humeral head in the ABER position after the RMBR procedure. These findings deepen the understanding of RMBR surgery in clinical practice and can assist physicians in deciding whether to choose this surgical approach in patients with combined HSL.

The coexistence of spinal degenerative diseases and hip joint degeneration is common among middle-aged and elderly individuals, causing significant suffering and economic burden for patients. Total hip arthroplasty (THA) and lumbar fusion (LF) are primary treatment options for this combined condition, but the impact of the surgical sequence on patient outcomes remains unclear. Hence, this study aims to evaluate the effects of the surgical sequence of THA and LF on symptom recovery, changes in sagittal spine-pelvis parameters, and the incidence of long-term complications in patients. A retrospective analysis was conducted on 104 patients diagnosed with hip-spine syndrome (HSS) who underwent THA and LF at the Chinese PLA General Hospital. IPTW was implemented to control potential confounding factors. The impact of surgical sequence on clinical function scores, radiological parameters, and long-term complications was evaluated before and after conducting IPTW. Patients who underwent THA surgery first, followed by LF surgery, were categorized as the THA→LF group; conversely, those who underwent LF surgery first, followed by THA surgery, were categorized as the LF→THA group. Clinical function scores included the Oswestry Disability Index (ODI), Japanese Orthopedic Association (JOA) score, and Harris Hip Score for both groups. Long-term complications assessed in this study included instances of Proximal Junctional Kyphosis (PJK), internal fixation loosening or failure, as well as hip prosthesis dislocation. Radiological parameters included Pelvic Tilt (PT), Pelvic Incidence (PI), Pelvic Incidence minus Lumbar Lordosis (PI-LL), Sacral Slope (SS), and Lumbar Lordosis (LL). Before conducting IPTW, there were significant differences between the two groups across multiple variables, including age (P = 0.035), fixation stage (P = 0.042), preoperative PT (P = 0.005), preoperative PI-LL (P = 0.004), and preoperative LL (P = 0.040). After conducting IPTW, all baseline data variables had P-values greater than 0.50, indicating that the baseline characteristics between the two groups were comparable. Following IPTW, the study found significant improvements in postoperative ODI, JOA score, and Harris Hip Score for both groups (P < 0.001), indicating that both surgical sequences were effective in enhancing clinical functional activity. However, there were no significant differences between the groups. Additionally, there was no significant difference in the long-term complication rates between the two groups. Regarding radiological parameters, the PT in the THA→LF group was significantly lower than that in the LF→THA group (P = 0.043), while the SS was significantly higher (P = 0.028) at the last follow up after conducting IPTW. Compared to preoperative assessments, both surgical sequences significantly improve postoperative clinical function scores and radiological parameters for patients. When comparing between the two groups, the surgical sequence exhibits equivalent effects on functional improvement and complication rates. The radiological outcomes indicate that the THA→LF group shows more pronounced effects on PT and SS, suggesting a more favorable impact on pelvic alignment in patients undergoing this sequence. The use of the IPTW method successfully eliminates differences in baseline characteristics, enhancing the reliability of the results. Future research is warranted to further explore these findings and their implications for surgical decision-making in HSS patients.

Background: The optimal position and number of anchors that need to be implanted in Hill-Sachs lesions (HSLs) during remplissage with Bankart repair (RMBR) to correct anterior glenohumeral instability remain unclear. Previous studies have mainly focused on anchor placement in the central, medial, and peripheral regions, as well as the superior and inferior poles of the HSL, but anchor placement in the upper or lower regions of the HSL has not been investigated. Purpose: To assess, using finite element analysis, the effect of placing 2 anchors in the superior or inferior regions of the HSL during RMBR on humeral head displacement and postoperative joint stability. Study Design: Controlled laboratory study Methods: Finite element models of the glenohumeral joint in the abduction external rotation position were created, including normal models and models with 2 anchors placed in the superior, inferior, or central regions of the HSL. Models with Bankart lesions and HSLs were established based on the normal glenohumeral joint model. Humeral head displacement was calculated by applying anterior dislocation forces and muscle contractions from the infraspinatus and teres minor muscles. Results: Models with 2 anchors placed in the superior (1.92 ± 0.00 mm) region of the HSL showed less anterior humeral head displacement than those with anchors in the lower (1.95 ± 0.00 mm) or central (1.95 ± 0.00 mm) regions under anterior dislocation load. However, posterior displacement was greater (2.05 ± 0.00 mm vs 1.90 ± 0.00 mm and 1.87 ± 0.00 mm) with anchors placed in the superior region under muscle contraction. Conclusion: The placement of 2 anchors in the upper portion of the HSL more effectively ( P < .001) reduced anterior humeral head displacement than did the placement of anchors in the lower or central regions of the HSL. In clinical practice, external forces on the shoulder joint comparable with those causing dislocation may amplify this displacement difference, rendering it more prominent and clinically relevant. This provides a more refined reference for determining the position and number of anchors that need to be implanted into the HSL during RMBR surgery. Clinical Relevance: The placement of 2 anchors in the upper region of the HSL effectively reduces anterior displacement under simulated dislocation loads, while increasing posterior displacement under muscle contraction. This may enhance postoperative glenohumeral stability and reduce the risk of recurrent dislocations, offering valuable insights for clinical practice.

Objective: Precise and reproducible control of wedge resection remains challenging in osteotomy correction for ankylosing spondylitis–related rigid kyphosis, and reports of robotic stereotactic execution beyond pedicle screw placement are limited. This technical note describes the operative workflow of robot‐assisted stereotactic osteotomy (RASO), focusing on quantitative wedge planning and stereotactic execution feasibility. Methods: The RASO technique and operative workflow are described. Patients with type II ankylosing spondylitis‐related thoracolumbar deformity who underwent single‐level three‐column RASO between May and November 2023 were analyzed. Preoperative planning was performed using Surgimap wedge simulation with ratio‐of‐closure–based prediction, and stereotactic osteotomy trajectories were executed using the Mazor X Stealth Edition system. Perioperative parameters and immediate postoperative radiographic findings were descriptively assessed to evaluate the feasibility and reliability of the proposed operative workflow. Results: This technique was successfully implemented in 15 patients. The mean operative duration was 304.2 ± 51.4 min, and the mean intraoperative blood loss was 486.7 ± 229.5 mL. Planning–execution concordance demonstrated acceptable agreement, with a maximal ratio‐of‐closure–related deviation of ≤ 5.18° and a mean difference of 0.2° between planned and achieved osteotomy Cobb angles. The mean thoracolumbar kyphosis (TLK) improved from 50.2° to 13.2°, the chin‐brow vertical angle (CBVA) improved from 36.7° to 15.1°, the PT improved from 35.6° to 26.6°, and the sagittal vertical axis (SVA) improved from 207.6 to 93.7 mm. Three intraoperative durotomies occurred during the decompression phase; one patient developed delayed cerebrospinal fluid leakage. No neurological deficits, hardware failure, or mortality were observed. All patients achieved osseous fusion and demonstrated improvements in health‐related quality of life measures. Conclusions: This technical note demonstrates the technical feasibility and workflow reliability of robot‐assisted stereotactic osteotomy for rigid ankylosing spondylitis–related thoracolumbar kyphotic deformity. Quantitative wedge planning can be reproducibly translated into robotic stereotactic intraoperative execution. Further studies are required to define the broader clinical role and potential applications of this technique. Trial Registration: Chinese Clinical Trial Registry: 2400090375.