[Mid-term effectiveness of hip preservation in the reconstruction of ultrashort bone segments in the proximal femur with three-dimensional printed customized cementless intercalary endoprosthesis with an intra-neck curved stem].

Objective: To explore the design points of a three-dimensional (3D) printed customized cementless intercalary endoprosthesis with an intra-neck curved stem and to evaluate the key points and mid-term effectiveness of its application in the reconstruction of ultrashort bone segments in the proximal femur. Methods: Between October 2015 and January 2021, 17 patients underwent reconstruction with a 3D printed-customized cementless intercalary endoprosthesis with an intra-neck curved stem. There were 11 males and 6 females, the age ranged from 10 to 76 years, with an average of 30.1 years. There were 9 cases of osteosarcoma, 4 cases of Ewing sarcoma, 2 cases of chondrosarcoma, 1 case of liposarcoma, and 1 case of myofibroblastoma. The disease duration was 5-14 months, with an average of 9.5 months. Enneking staging included 16 cases of stage ⅡB and 1 case of stage ⅢB. The distances from the center of the femoral head to the body midline and the acetabular apex were measured preoperatively on X-ray images. Additionally, the distances from the tip of the intra-neck curved stem to the body midline and the acetabular apex were measured at immediate postoperatively and last follow-up. The neck-shaft angle was also measured preoperatively, at immediate postoperatively, and at last follow-up. The status of osseointegration at the bone-prosthesis interface and bone growth into the prosthesis surface were assessed by X-ray films, CT, and Tomosynthesis-Shimadzu metal artefact reduction technology (T-SMART). The survival status of the patients, presence of local recurrence or distant metastasis, and occurrence of postoperative complications were assessed. The recovery of lower limb function was evaluated pre- and post-operatively using the Musculoskeletal Tumor Society (MSTS) scoring system, and pain relief was evaluated using the visual analogue scale (VAS) scores. Results: The patient's femoral resection length was (163.1±57.5) mm, the remaining proximal femoral length was (69.6±9.3) mm, and the percentage of femoral resection length/total femoral length was 38.7%±14.6%. All 17 patients were followed up 25-86 months with an average of 58.1 months. During the follow-up, 1 patient died of lung metastasis at 46 months postoperatively, and the remaining 16 patients survived tumor-free. There was no complication such as periprosthetic infection, delayed incision healing, aseptic loosening, prosthesis fracture, or periprosthetic fracture. No evidence of micromotion or wear around the implanted stem of the prosthesis was detected in X-ray and T-SMART evaluations. There was no significant radiolucent lines, and radiographic evidence of bone ingrowth into the bone-prosthesis interface was observed in all stems. There was no significant difference in the distance from the tip of the curved stem to the body midline and the apex of the acetabulum at immediate postoperatively and last follow-up compared with the distance from the center of the femoral head to the body midline and the apex of the acetabulum before operation, respectively (P>0.05), and there was no significant difference in the above indexes between immediate postoperatively and last follow-up (P>0.05). The differences in the neck-shaft angle at various time points before and after operation were also not significant (P>0.05). At last follow-up, the MSTS score was 26.1±1.2 and the VAS score was 0.1±0.5, which were significantly improved when compared with those before operation [19.4±2.1 and 5.7±1.0, respectively] (t=14.735, P<0.001; t=21.301, P<0.001). At last follow-up, none of the patients walked with the aid of crutches or other walkers. Conclusion: The 3D printed customized cementless intercalary endoprosthesis with an intra-neck curved stem is an effective method for reconstructing ultrashort bone segments in the proximal femur following malignant tumor resection. The operation is reliable, the postoperative lower limb function is satisfactory, and the incidence of complications is low.

Predictor of Surgical Outcomes in Ankylosing Spondylitis Cervical Spinal Fracture: An At Least 2 Years Follow-Up Retrospective Study.

STUDY DESIGN: Retrospective study. OBJECTIVE: A retrospective study was conducted to clarify the prognostic factors of postoperative for cervical spine fractures patients with ankylosing spondylitis (AS). SUMMARY OF BACKGROUND DATA: Now the high probability of cervical fractures in patients with AS is unanimously recognized. Fractures mostly occur in the lower cervical spine and two-thirds of patients are accompanied by spinal cord injury. But there are few studies on treatment of AS patients with cervical fracture and it is unclear whether the surgical method, timing of surgery, basic treatment of AS, and different doses of steroids therapy have an impact on the prognosis. Thus, this study aims to evaluate the impact of perioperative factors on the prognosis of traumatic cervical fractures in surgical patients with AS. METHODS: Preoperative and postoperative spinal cord function were assessed according to the Japanese Orthopaedic Association (JOA) Scores and Improvement rate were calculated. The neck pain severity were rated using a visual analogue scale (VAS) score. The t test and v2-test were used for comparison of clinical data between the preoperative and postoperative groups. Logistic univariate and multivariate regression analysis were used to obtain adjusted odds ratios. Pearson correlation coefficients were used to evaluate the relationship between variables. RESULTS: The degree of fracture displacement in cervical spine fractures patients with AS was most common at the neck-chest junction (26.1%). Patients with degree of cervical fracture displacement less than 50% had significantly improved JOA scores after surgery (P = 0). The incidence of spinal cord injury (SCI) due to fracture was high (52.2%). Patients with combined anterior and posterior is helpful for neurological recovery (P = 0.01). Basic AS treating before injury would be benefit for neurological improvement (P = 0). CONCLUSION: Basic AS treatment, SCI, and surgical methods are independent factors that affect the prognosis of cervical spine fractures patients with AS. It is controversial to perform surgery and preoperative steroid application as soon as possible. LEVEL OF EVIDENCE: 3.