Background: Both cylindrical and tapered stems are commonly used in revision total hip arthroplasty. However, whether the geometry of prosthesis stem has an effect on patient prognosis is unclear. We assume that the tapered stem results in better clinical outcome than the cylindrical stem. Methods: A multicenter review of 120 femoral revisions with Paprosky I, II, and III defects using cobalt chrome cylindrical stem (54 hips) or titanium tapered stem (66 hips) was performed with an average follow-up of 6 years. Demographic data were comparable between groups. Results: No significant group differences were found in surgery time, bleeding volume, postoperative Harris Hip Score, level of overall satisfaction, and 8-year cumulative survival. However, intraoperative fractures occurred significantly less in the tapered group (4.5%) than in the cylindrical group (14.8%), and stem subsidence was significantly less in the tapered group (2.17 mm) than in the cylindrical group (4.17 mm). A higher ratio of bone repair and lower bone loss were observed in the tapered group compared with the cylindrical group. The postoperative thigh pain rate was higher in the cylindrical group (12.9%) than in the tapered group (4.5%). Conclusion: Both cylindrical stem and tapered stem can achieve satisfactory mid-term clinical results in revision total hip arthroplasty. The tapered stem has better bone restoration of proximal femur, lower incidence of intraoperative fractures, and lower postoperative thigh pain rate compared with the cylindrical stem.

Study Design. Retrospective study. Objective. To investigate whether magnetic resonance imagingbased vertebral bone quality (VBQ) score can predict pedicle screw loosening in patients who underwent pedicle screw fixation, and to compare, which measurement, the VBQ score or the Hounsfield unit (HU) value, is more predictive of pedicle screw loosening. Summary of Background Data. In clinical work, we found that patients with screw loosening had higher VBQ scores. In addition, some studies have found a correlation between VBQ scores and osteoporosis. Patients and Methods. Patients who were treated with lumbar pedicle screw fixation were reviewed. The VBQ score was measured using magnetic resonance imaging scans. The HU value for L1 to L4 lumbar bone mineral density was measured with computed tomography scans. Logistic regression analysis was used to identify factors associated with pedicle screw loosening. Receiver-operating characteristic curve analysis was used to evaluate the value of VBQ scores in predicting pedicle screw loosening. Results. A total of 156 patients were included in the final analysis. The pedicle screw loosening rate was 35% (55 of 156 patients). The postoperative low-back pain visual analog scale score was higher in the loosening group (3.0 ± 2.0 vs. 2.4 ± 1.8; P < 0.05). The VBQ score was higher in the loosening group than in the nonloosening group (3.28 ± 0.58 vs. 2.82 ± 0.50; P < 0.01). In multivariable analysis, nonsingle segment fixation [odds ratio (OR): 3.992; 95% CI: 1.643-9.701; P = 0.002], lowest instrumented vertebrae at S1 (OR: 3.378; 95% CI: 1.387-8.226; P = 0.007), HU value (OR: 0.988; 95% CI: 0.976-1.000; P = 0.047), and VBQ score (OR: 3.908; 95% CI: 1.624-9.405; P = 0.002) were factors associated with screw loosening. The areas under the curve for using the VBQ score and HU value to predict pedicle screw loosening were 0.720 and 0.702, respectively. The optimal VBQ score threshold was 3.05 for predicting pedicle screw loosening (sensitivity: 0.655; specificity: 0.713). Conclusions. The VBQ score was an influential factor associated with lumbar pedicle screw loosening, and a higher VBQ score was significantly correlated with a higher risk of screw loosening. The VBQ score was a better predictor of pedicle screw loosening than the HU value in patients who underwent pedicle screw fixation for degenerative lumbar disease.

Objective The objective of this study was to explore the impact of sarcopenia and sagittal parameters on the residual back pain (RBP) after percutaneous vertebroplasty (PVP) for treatment of osteoporotic vertebral compression fracture (OVCF). Methods This retrospective study included elderly patients (age range 60–90 years) with OVCF treated with PVP from January 2015 and December 2020 in our hospital. The skeletal muscle mass index (SMI) was calculated by dividing the T12 pedicle level muscle cross-sectional area by the square of body height from chest CT to diagnose sarcopenia. The radiological parameters for measuring the sagittal alignment were included: C7-sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI). Result According to whether the VAS score > 4, patients were divided into RBP group (56 patients) and Control group (100 patients). There was no difference in age, gender, body mass index, BMD, surgical segment, bone cement usage between the groups (P > 0.05). The SMI in RBP group (27.3 ± 5.1) was significantly lower compared to that in Control group (36.8 ± 3.2) (P < 0.05). Sarcopenia was present in 19 patients (20.3%) in RBP group, which was significantly more than that in Control group (P < 0.05). C7-SVA and TPA was significantly larger in the RBP group than in the Control group (P < 0.05). PI and LL was significantly smaller in the RBP group compared to the Control group (P < 0.05). However, no significant differences between the two groups with respect to TK, SS and PT (P > 0.05). Conclusion Poor sagittal parameters and sarcopenia in OVCF patients after PVP were more prone to residual back pain. Larger C7-SVA, TPA and PI-LL mismatch could increase the incidence of RBP in elderly patients with single-segment osteoporotic compression fractures.

Background To evaluate the survival rate of porous tantalum rod implantation in the treatment of osteonecrosis of the femoral head (ONFH), evaluate its clinical effect and imaging results. Methods From January 2008 to December 2013, porous tantalum rod implantation for ONFH was performed in two institutions. Statistical analysis of operation data, including operation time, blood loss and blood transfusion were recorded. Results 52 hips received complete follow-up, the average follow-up time was 85.7 months (60–132 months). 24 hips turned to THA at the end of follow-up (46.2%), the average time was 44.3 ± 32.8 months, and the average Harris hip score before THA was 57.1 ± 7.6. Cox proportional-hazards model revealed that Association Research Circulation Osseous (ARCO) stage (P = 0.017), bone marrow edema (P = 0.006) and age > 40 years (P = 0.043) were independent risk factors for conversion to THA. Conclusion ARCO stage, age and bone marrow edema were risk factors for the failure of porous tantalum rod implantation to convert to THA.

Objective The objective of this study was to explore the morphological characteristics of paraspinal muscles in young patients with unilateral neurological symptoms of lumbar disc herniation. Methods This study retrospectively analyzed young patients aged 18–40 years who were hospitalized for lumbar disc herniation in our hospital from June 2017 to June 2020. Data on sex, age, body mass index (BMI), subcutaneous fat tissue thickness (SFTT) at the L1-L2 level, duration of symptoms, degree of lumbar disc herniation, visual analog scale (VAS) for the lower back, Mo-fi-disc score, relative cross-sectional area (RCAS) of the paravertebral muscles (psoas major [PM], multifidus [MF], and erector spinae [ES]), and degree of fat infiltration (DFF) of the paravertebral muscles were collected. The VAS was used to evaluate the intensity of low back pain. Patients with VAS-back >4 points were defined as the low back pain group, and patients with ≤4 points were defined as the control group. The demographic characteristics, as well as the bilateral and ipsilateral paravertebral muscles, of the two groups were compared and analyzed. Result A total of 129 patients were included in this study (52 patients in the LBP group and 77 patients in the control group). There were no significant differences in sex, BMI, or Pfirrmann grade of lumbar disc herniation between the two groups (P > 0.05). The age of the LBP group (33.58 ± 2.98 years) was greater than that of the control group (24.13 ± 2.15 years) (P = 0.002), and the SFTT at the L1-L2 level (13.5 ± 7.14 mm) was higher than that of the control group (7.75 ± 6.31 mm) (P < 0.05). Moreover, the duration of symptoms (9.15 ± 0.31 months) was longer than that of the control group (3.72 ± 0.48 months) (P < 0.05), and the Mo-fi-disc score (8.41 ± 3.16) was higher than that of the control group (5.53 ± 2.85) (P < 0.05). At L3/4 and L5/S1, there was no significant difference in the RCSA and DFF of the bilateral and ipsilateral paraspinal muscles between the LBP group and the control group. At L4/5, there was no significant difference in the RCSA and DFF of the paraspinal muscles on either side in the LBP group (P > 0.05). In the control group, the RCSA of the MF muscle on the diseased side was smaller than that on the normal side (P < 0.05), and the DFF of the MF muscle on the diseased side was larger than that on the normal side (P < 0.05). In addition, there was no significant difference in the ES and PM muscles on both sides (P > 0.05). At L4/5, the RCSA of the MF muscle on the normal side was significantly smaller in the LBP group than in the control group (P < 0.05), and the DFF of the MF muscle on the normal side was significantly larger in the LBP group than in the control group (P < 0.05). There was no significant difference in the ES and PM muscles on the same side between the two groups (P > 0.05). Conclusion In young patients with unilateral neurological symptoms of lumbar disc herniation, symmetrical atrophy of the bilateral MF muscle is more prone to causing low back pain. Older age, higher SFTT at the L1-L2 levels, longer symptom duration, higher Mo-fi-di score, and greater muscle atrophy on the normal side of the MF increased the incidence of low back pain in young patients with unilateral lumbar disc herniation.