Objective To explore the influencing factors of age at onset of pain and severe pain in patients with Hartofilakidis type I developmental dysplasia of the hip (DDH). Methods A retrospective study of 83 patients with DDH treated at our hospital from January 2017 to June 2021 was conducted. The age at onset of pain, patients’ demographic data, and radiographic parameters were collected. Multiple linear regression was used to determine the influencing factors of age at onset of pain. Cox regression analysis was used to determine the influencing factors of severe pain attacks. Results According to the results of multiple linear regression analysis, when the distance between the medial femoral head and the ilioischial line increased by one millimetre, the age at onset of pain decreased by 1.7 years (β = − 1.738, 95% CI − 1.914–[− 1.561], p < 0.001). When the sharp angle increases by one degree, the age at onset of pain decreases by 0.3 years (β = − 0.334, 95% CI − 0.496–[− 0.171], p < 0.001). According to the results of the Cox regression analysis, for each additional degree of the lateral centre-edge angle (LCEA), the probability of severe pain was reduced by 5% (Exp [β]: = 0.947, 95% CI 0.898–0.999, p = 0.044). For each additional millimetre in the distance between the medial femoral head and the ilioischial line, the likelihood of severe pain increased by 2.4 times (Exp [β]: 2.417, 95% CI 1.653–3.533, p < 0.001). Conclusion Larger distances between the medial femoral head and the ilioischial line and sharp angle can lead to an earlier age at onset of pain in patients with DDH. Small LCEA and excessive distance between the medial femoral head and the ilioischial line are risk factors for severe pain.

ObjectiveTo introduce a surgical technique (the “Y” line technique) that will control leg length discrepancy (LLD) after total hip arthroplasty and to observe its effectiveness and influencing factors.MethodsAccording to the inclusion and exclusion criteria, a total of 350 patients were selected in this study; 134 patients in whom used the “Y” line technique was used to control lower limb length were included in Group A and 166 patients treated with freehand methods to control lower limb length were included in Group B. A total of 50 patients in whom the standard anteroposterior x-ray of bilateral hips was taken preoperatively and in whom the “Y” line technique was used during the operation were included in Group C.ResultsThe postoperative LLD of Group A was 4.74 mm (3.93), that of Group B was 5.85 mm (4.60), and that of Group C was 2 mm (1.00)—the difference was statistically significant (p &lt; 0.001). There were significant statistical differences when comparisons were made between any two groups (p &lt; 0.01). The distribution of postoperative LLD in Group A was better than that in Group B, and this factor was better in Group C than in Group A—the difference was statistically significant (p &lt; 0.001). Severe unequal length rates of the lower extremities (LLD &gt; 10 mm) were 5.97% (8/134) in Group A, 14.3% (24/166) in Group B, and 0% (0/50) in Group C—the difference was statistically significant (p &lt; 0.001). There were significant differences between Group A and Group B and between Group B and Group C (p &lt; 0.05), but there was no significant difference between Group A and Group C (p = 0.078).ConclusionThe “Y” line technique, which does not increase the operating time and patient cost, can effectively reduce postoperative LLD. Insufficient internal rotation of the healthy lower extremity and the low projection position in the preoperative anteroposterior x-ray of the bilateral hips were important factors affecting the accuracy of the “Y” line technique.

Background and purpose There are recognized surgical indications for Bernese periacetabular osteotomy (PAO), but the degree of postoperative functional recovery is significantly different through clinical observation and follow-up. Therefore, it is necessary to do a preoperative evaluation. This study aims to screen the factors influencing functional recovery after PAO and construct a predictive nomogram.Patients and methods: Retrospective data were collected between December 2016 and March 2022 at The First Affiliated Hospital of Shandong First Medical University, including demographic data and imaging materials of patients undergoing PAO. The least absolute shrinkage and selection operator regression was used to screen the influencing factors, and then multivariate logistic regression analysis was employed to construct a predictive nomogram for predicting functional recovery after PAO.Result The influencing factors of functional recovery after PAO were screened out, namely the preoperative distance from the innermost surface of the femoral head to the ilioischial line, surgical approach, preoperative acetabular depth, and preoperative Calve line continuity. A nomogram model was established using these significant predictors. The receiver-operating characteristic curve was drawn, and the area under the curve was calculated to be 0.864. The calibration curve showed that the constructed nomogram model was well calibrated. There was sufficient consistency between the observed and estimated prediction probabilities to indicate that the clinical prediction model had high accuracy.Conclusion This predictive nomogram can identify the patients most suitable for PAO and can be used to guide the selection of surgical patients and surgical approaches.