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Objectives: The restoration of as much normal function as possible has become an important goal following the endoprosthetic reconstruction. The objective of this study was to assess the functional outcome after endoprosthetic reconstruction for tumors around the knee and to explore prognostic factors of functional outcome. Methods: We retrospectively collected data on patients who underwent tumor prosthetic replacements consecutively. Musculoskeletal Tumour Society score and Toronto Extremity Salvage Score were used to assess the functional outcome at 1, 3, 6, 12, and 24 months after surgery. The logistic model was used to select factors that had potential predictive value for postoperative function. Potential prognostic factors included age, gender, tumor site, type of tumor, length of bone resection, type of prosthesis, length of prosthetic stem, chemotherapy, pathological fracture, and body mass index. Results: At the 24 months after surgery, the mean musculoskeletal tumor society (MSTS) score was 81.4% and the mean Toronto extremity salvage score (TESS) was 83.6%. At the last follow-up, 68% of patients and 73% of patients received perfect or good MSTS score and TESS score, respectively. The multivariate analysis according to ordered-logit model showed that age < 35 years, distal femoral prosthesis, and length of bone resection < 14 cm were independent prognostic factors of better functional outcome. Conclusions: Endoprosthetic reconstruction may provide good functional results for most patients. Younger patients with distal femoral prosthesis and shorter resection of bone (on the premise of complete resection of tumor) are more likely to obtain satisfactory functional results after surgery. [ABSTRACT FROM AUTHOR]

Objective: To explore the potential effect of three allogenic bone substitute configurations on the viability, adhesion, and spreading of osteoblasts in vitro. Methods: Freeze‐dried cortical bone were ground and fractions were divided into three groups with different sizes and shapes, defined as bone fiber (0.1 mm × 0.1 mm × 3 mm), bone powder (0.45–0.9 mm), and bone granule group (3–6 mm). MC3T3‐E1 cells were divided and co‐cultured within groups to induce cell adhesion. The configuration of allogenic bone was captured by scanning electron microscopy and confocal laser scanning microscopy, and substrate roughness values were quantified. Cell adhesion rate was assessed using the hemocyte counting method, cell viability was determined by CCK‐8 assay and live/dead staining, and cell morphology was visualized by Phalloidin and DAPI, and the mRNA expression of adhesion‐related gene (vinculin) of different substitutes were determined with quantitative real‐time polymerase chain reaction. Results: The roughness values of bone fiber, bone powder, and bone granule group were 1.878 μm (1.578–2.415 μm), 5.066 μm (3.891–6.162 μm), and 0.860 μm (0.801–1.452 μm), respectively (bone powder group compared with bone granule group, H = 18.015, P < 0.001). Similar OD values of all groups in CCK‐8 assay indicated good biocompatibility of these substitutes (bone fiber, 0.201 ± 0.004; bone powder, 0.206 ± 0.008; bone granule group, 0.197 ± 0.006; and the control group, 0.202 ± 0.016, F = 0.7152, P > 0.05). In addition, representative cell adhesion rates at 24 h showed significantly lower cell adhesion rate in bone fiber group (20.3 ± 1.6%) compared to bone powder (29.3 ± 4.4%) and bone granule group (27.3 ± 3.2%) (F = 10.51，P = 0.009 and P = 0.034, respectively), but there was no significant difference between the latter two groups (P > 0.05). Interestingly, the expression of vinculin mRNA steadily decreased in a time‐dependent manner. The vinculin expression reached its peak at 6 h in each group, and the vinculin levels in bone fiber, bone powder, and bone granule group were 2.119 ± 0.052, 3.842 ± 0.108, and 3.585 ± 0.068 times higher than those in the control group, respectively (F = 733.643, all P < 0.001). Meanwhile, there was a significant difference in the expression of target gene between bone powder and bone granule group (P = 0.006). Conclusion: All allogenic bone substitutes presented an excellent cell viability. Moreover, bone powder and bone granule group were more likely to promote cell adhesion and spreading compared to bone fiber group. [ABSTRACT FROM AUTHOR]

Objective: For reconstructing the posterior cervical muscular–ligament complex, attachment points and various modified techniques were designed and applied in clinical practice. This study investigated the clinical and radiographic outcomes of open door laminoplasty with modified centerpiece mini‐plate fixation and extensor attachment point reconstruction in the treatment of cervical spondylotic myelopathy (CSM). Methods: Sixty‐nine patients with CSM who underwent C3–C7 open door laminoplasty at our hospital from January 2016 to May 2018 were divided into two groups: 37 and 32 patients underwent laminoplasty with modified and conventional centerpiece titanium plate fixation (MPF and CPF groups), respectively. Changes in cervical spinal angle (CSA), cervical range of motion (ROM), posterior cervical muscle atrophy, neurological function (Japanese Orthopaedic Association [JOA] score), Neck Disability Index (NDI), and axial symptom severity were compared between the two groups. Results: There were no significant differences in operative duration (136.7 ± 23.9 vs 128.3 ± 21.5 min, t = 1.525, p > 0.05), volume of intraoperative blood loss (275.9 ± 33.1 vs 268.2 ± 31.6 ml, t = 0.984, p > 0.05), lamina open angle (41.2° ± 4.5° vs 39.4° ± 4.1°, t = 1.726, p > 0.05), and spinal cord drift distance (2.4 ± 0.3 vs 2.3 ± 0.4 mm, t = 1.184, p > 0.05) between the two groups. After surgery, JOA score significantly increased (p < 0.05), and neurological recovery rates were similar (62.7% vs 63.4%, t = 0.208, p > 0.05). The NDI score was significantly decreased in both the groups (p < 0.05); however, the MPF group recovered to a greater degree than the CPF group (8.3 ± 1.2 vs 9.8 ± 1.4) (t = 4.793, p < 0.05). There was no significant change in cervical ROM postoperatively compared with preoperatively in either group (p > 0.05). CSA decreased from 21.7° ± 2.8° to 18.3° ± 2.1°, and posterior cervical muscle cross‐sectional area decreased from 35.2 ± 4.9 cm2 to 31.0 ± 4.1 cm2 in the CPF group (p < 0.05), but no significant change was observed in the MPF group (20.6° ± 2.5° to 20.4° ± 2.6°and 35.9 ± 5.1 to 34.1 ± 4.6 cm2, respectively) (p > 0.05). Postoperative axial symptom severity was significantly worse in the CPF group than in the MPF group (Z = −2.357, p < 0.05). Conclusions: As an improvement to the conventional titanium plate, the modified centerpiece titanium plate effectively provides an attachment point for the posterior muscle–ligament complex, reducing posterior cervical muscle atrophy and improving neck function, without inflicting additional surgical trauma. [ABSTRACT FROM AUTHOR]