Objective To investigate the safety and efficacy of a new biodegradable magnesium internal fixation screw for vascularized iliac bone flap grafting in treatment of osteonecrosis of the femoral head (ONFH). Methods Patients with ONFH admitted between July 2020 and February 2021 were selected as the research objects, and 20 patients (20 hips) met the selection criteria and were included in the study. The patients were divided into two groups (n=10) by central random method. The iliac bone flap was fixed with a new biodegradable magnesium internal fixation screw in the trial group, and the iliac bone flap was wedged directly in the control group. There was no significant difference (P>0.05) in gender, age, and side, type, Association Research Circulation Osseous (ARCO) stage, and disease duration of ONFH between the two groups. The operation time and intraoperative blood loss of the two groups were recorded. Laboratory tests were performed at each time point before and after operation, including white blood cell (WBC), electrolytes (K, Ca, P, Mg), blood urea nitrogen (BUN), serum creatinine (Scr), glomerular filtration rate (eGFR), lymphocyte ratio (CD4/CD8), immunoglobulin G (IgG), IgM, alanine transaminase (ALT), aspartate aminotransferase (AST). After operation, Harris score was used to evaluate the hip joint function. CT of the hip joint and X-ray films in anteroposterior and frog positions of the pelvis were used to review the iliac bone flap position, fusion, and screw biodegradation in the trial group. Results The vital signs of the two groups were stable, the incisions healed by first intention, and no adverse events occurred after operation. One patient in the control group refused to return to the hospital for follow-up at 3 months after operation, and 1 patient in the trial group refused to return to the hospital for follow-up at 1 year after operation. The rest of the patients completed the follow-up at 2 weeks, 3 months, 6 months, and 1 year after operation. Laboratory tests showed that there was no significant difference in WBC, electrolytes (K, Ca, P, Mg), BUN, Scr, eGFR, CD4/CD8, IgG, IgM, ALT, and AST between the two groups at each time point before and after operation (P>0.05). The operation time and intraoperative blood loss of the trial group were significantly less than those of the control group (P<0.05). The Harris scores of the two groups at 1 year significantly increased when compared with the values before operation and at 6 months after operation (P<0.05). There was no significant difference in Harris score between the two groups at each time point (P>0.05). Postoperative CT of hip joint and X-ray films of pelvis showed that the iliac bone flap reached osseous fusion with the fenestration of the head and neck junction of femoral head in the two groups at 1 year after operation, and no loosening or shedding of iliac bone flap was observed during follow-up. In the trial group, there were signs of dissolution and absorption of the new biodegradable magnesium internal fixation screws after operation, and the diameter of the screws gradually decreased (P<0.05); no screw breakage or detachment occurred during follow-up. Conclusion In the treatment of ONFH with vascularized iliac bone flap grafting, the new biodegradable magnesium internal fixation screws can fix the iliac bone flap firmly. Compared with the traditional iliac bone flap wedging directly, it has a shorter operation time, less intraoperative blood loss, and can obtain similar joint function.
Objective To evaluate the mid-term effectiveness of cerclage wires fixation in treating Mallory typeⅡperiprosthetic femoral fractures associated with primary hip arthroplasty. Methods A retrospective analysis was made in the data of 14 patients (14 hips) with Mallory typeⅡ periprosthetic femoral fractures associated with primary hip arthroplasty and treated with cerclage wires fixation between January 2010 and June 2011 (fracture group). Twenty-eight patients (28 hips) without periprosthetic femoral fractures associated with primary hip arthroplasty at the same stage were chosen as control group. The uncemented femoral prosthesis were used in 2 groups. There was no significant difference in gender, age, body mass index, and primary disease between 2 groups (P>0.05). The operation time, intraoperative blood loss, and the complications were recorded. The Harris score was used to evaluate the hip function and the visual analogue scale (VAS) score was used to evaluate the pain degree of hip. According to the postoperative X-ray films of hips, Enghet al. standard was used to evaluate the fixed and stable status of the femoral prosthesis; the heterotopic ossification was observed; the time of fracture union was recorded. Results The operation time of fracture group was significantly longer than that of control group (t=–3.590, P=0.001). There was no significant difference in the intraoperative blood loss between 2 groups (t=–1.276, P=0.209). All patients were followed up 64-75 months (mean, 69.5 months). Hip dislocation after operation occurred in 1 case of fracture group; delirium symptom and nonunion of incision occurred in 1 case and 1 case of control group, respectively. There was no significant difference in the Harris score and VAS score at 6 months and 5 years between 2 groups (P>0.05). X-ray films showed that all fractures healed and the mean time of fracture union were 6.1 months (range, 3-12 months). There was no fracture nonunion or malunion evidently. There was no significant difference in X-ray score at 6 months and 5 years between 2 groups (P>0.05). At last follow-up, cerclage wires displacement or breakage did not occur. Heterotopic ossification occurred in 2 cases of fracture group and in 1 case of control group. Conclusion Cerclage wires fixation can achieve the good mid-term effectiveness in treating Mallory typeⅡintraoprative periprosthetic femoral fractures associated with primary hip arthroplasty.