BackgroundAnterior cervical decompression and fusion (ACDF) has long been the preferred treatment for cervical spondylotic myelopathy (CSM). However, few studies have focused on surgical results of CSM in patients with developmental canal stenosis (DCS). The purpose of this study was to investigate DCS as a comorbidity in patients with CSM and the correlation between surgical results and DCS.MethodsFrom January 1995 to December 2005, 122 patients treated with ACDF for CSM were enrolled in this retrospective study. Pavlov’s ratio was used to evaluate cervical spinal canal size, with a value of < 0.82 at least one level indicating DCS. Patients were divided into two groups: those with DCS preoperatively (DCS group, n = 50 [41.0 %]) and those without DCS (non-DCS group, n = 72). Clinical data and radiological parameters were compared between groups.ResultsThere were no significant differences in preoperative and 2-year follow-up Japanese Orthopedic Association scores between groups. Both groups achieved satisfactory fusion rates (DCS, 92.0 %; non-DCS, 93.0 %). Adjacent-segment degeneration (ASD) was detected in 66.0 % of patients in the DCS group and in 43.0 % of patients in the non-DCS group (p = 0.01). However, there was no significant difference in the incidence of ASD requiring surgery between groups (p = 0.20).DiscussionDCS is a common comorbidity in patients with CSM. The findings of this study have added knowledge on the correlation between DCS and ASD after anterior fusion surgery.ConclusionsDCS did not affect neurologic improvement postoperatively at short-term follow-up. Although DCS increased the incidence of ASD after anterior fusion, it did not predict ASD requiring surgery. Therefore, patients with DCS must receive close follow-up.

Surgical decision making for femoral neck fractures is currently based on factors such as patient age, fracture type, and medical condition, lacking a quantitative standard. The treatment protocol based on such qualitative assessment has poor operability, greatly affected by the surgeon's subjective factors. As a result, a quantitative score system (QSS) focusing on 5 factors--age, fracture type, bone mineral density, activities of daily living, and medical comorbidities--with a total score of 25 is designed to deal with adult femoral neck fractures. The higher the score, the worse the patient's physiological condition. According to our clinical experience, patients with 1 to 11 points should be treated with internal fixation; patients with 12 to 17 points with total hip arthroplasty (THA), and patients with 18 to 22 points with hemiarthroplasty. Patients with 22 to 25 points should be treated with internal fixation due to the high surgical risk of arthroplasty caused by poor physiological condition. Three hundred seventy-five adult femoral neck fractures were treated on the basis of QSS for this 2-year prospective study. Of these, 242 were treated with low-score internal fixation, 60 with THA, 55 with hemiarthroplasty, and 18 with high-score internal fixation. The revision rates 2 years postoperatively in the low-score internal fixation, THA, and hemiarthroplasty groups were 15.3%, 5.0%, and 5.5%, respectively, which were lower than those from a meta-analysis (internal fixation, 35%; THA, 16%). This QSS helps surgical decision making regarding the treatment choice for adult patients with femoral neck fractures, and good results in preliminary clinical practice have been achieved.

A numerical simulation approach of ventilated cavity considering the compressibility of gases is established in this paper, introducing the gas state equation into the calculation of ventilated supercavitating flow. Based on the comparison of computing results and experimental data, we analyzes the differences between ventilated cavitating flow fields with and without considered the compressibility of gases. The effect of ventilation on the ventilated supercavitating flow field structure is discussed considering the compressibility of gases. The results show that the simulation data of cavity form and resistance, which takes the compressibility of gases into account, accord well with the experimental ones. With the raising of ventilation temperature, the gas fraction in the front cavity and the gas velocity in the cavity increase, and the cavity becomes flat. The resistance becomes lower at high ventilation temperature, but its fluctuation range becomes larger than that at low temperature.

Introduction: The objective of this study was to explore mid-term clinical results of cementless total hip arthroplasty (THA) with modified trochanteric osteotomy in Crowe type IV developmental dysplasia of the hip (DDH).Patients and method: Thirteen patients (13 hips) with Crowe type IV DDH who underwent THA used modified trochanteric osteotomy between May 2013 and October 2019 were retrospectively analyzed. Mean follow-up was 5.2 ± 0.8 years (range, 4.9-6.1 years).Results: Mean Harris Hip Score (HHS) significantly (p < 0.05) improved from 30.7 ± 5.8 (range, 22-38) to 87.5 ± 3.6 (range, 83-93). The mean leg length discrepancy (LLD) was 53.4 ± 9.1 mm (range, 42.1-68.5 mm) preoperatively. The final LLD was 5.6 ± 2.4 mm (range, 2.4-9.1 mm). The mean leg length after surgery was 47.4 ± 10 mm (range, 33.6-67.2 mm). The average duration of bone union for greater trochanter (GT) was 2.5 ± 0.6 months (range, 1.5-3.6 months). There was no infection, GT non-union, or loosening (septic or aseptic) of the stem or cup in any case.Conclusions: THA with modified trochanteric osteotomy with cementless cup is an effective treatment for Crowe type IV developmental dysplasia of the hip. It can rebuild complex biomechanics and biology of hip dysplasia without increasing complications.