Objective To evaluate the effect of minimally invasive dynamic hip screws (MIDHS) in treating aged intertrochanteric fractures. Methods From April 2006 to March 2008, 49 aged patients with intertrochanteric fractures were treated with MIDHS. There were 22 males and 27 females, aged 65-78 years (average 70.2 years). Frature was caused by trafficaccident in 7 cases, by fall ing from height in 3 cases, and by injury from fall in 39 cases. The time from injury to operation was 2-12 days (average 5.5 days). According to Evans classification, there were 28 cases of types I, II (stable fracture) and 21 cases of types III, IV (unstable fracture). If the Singh index≤3 was defined as osteoporosis, the osteoporotic rate was 71.4% (35/49). All patients were on a radiolucent fracture traction table and their fractures had satisfactory closed reduction. After the guide wire was inserted and reamed under fluoroscopy, the lag screw and side plate were introduced through the small incision. In all unstable fractures, an additional, antirotational and large cancellous bone screw was used cranial to the DHS. Results The average operation time was 65.2 minutes. The average blood loss was 189.3 mL. All patients had satisfactory reduction and 79.6% (39/49) had adequate lag screw positions. The average postoperative hospital ization days was 5.8 days (3-12 days). All incision healed at stage I. There was no postoperative complications. Forty-nine patients were followed up 12 to 30 months (average 19.8 months). Fractures healed within 16 weeks in 47 patients and the average healing time was 13.1 weeks (12-16 weeks). The average Harris scoring was 90.8 (75-95). Implant failure and nonunion occurred in 2 cases, no serious compl ication occurred in other patients. Conclusion The MIDHS is a simple, safe and effective method for treatment of aged intertrochanteric fractures.
Objective To investigate the validity of improving the femur’s mechanical characteristics by implanting calcium phosphate ceramic screws after removing dynamic hip screw (DHS). Methods The three dimensional finite element model of the femur was built based on the CT scanning of a normal male volunteer. Then the models of the femur with and without DHS were established. According to calcium phosphate ceramic screws with porosity and apparent elastic modulus, 80% and 0.1 GPa were set as group A, 50% and 1.0 GPa as group B, and 30% and 1.5 GPa as group C. Von Mises stress distribution and maximum stress were recorded when the joint was maximally loaded in a gait cycle. Results The Von Mises in normal femoral shaft was uniform; no phenomena of stress concentration was observed and the maximum stress located at the joint load-bearing site of the proximal femur. The stress concentration was observed in the femur without DHS, and the maximum stress located at the distal femur around the screw hole. By comparing several different calcium phosphate ceramic screws, the stress distribution of group B was similar to normal femur model, and the maximum stress located at the joint load-bearing site. The other screws of groups A and C showed varying degrees of stress concentration. Conclusion Implanting calcium phosphate ceramic screw can improve the mechanical characteristics of the femur after removing dynamic hip screw, and the calcium phosphate ceramic screw with 50% porosity and 1.0 GPa apparent elastic modulus is suitable for implanting.
ObjectiveTo explore the effectiveness of dynamic hip screw (DHS) and intralesional curettage via Watson-Jones approach in treatment of benign bone lesions of the proximal femur.MethodsBetween March 2012 and December 2016, 20 patients (21 lesions) with benign bone tumors or tumor like conditions of proximal femurs were treated with DHS and intralesional curettage via Watson-Jones approach. Their average age was 27.8 years (range, 11-51 years), including 13 males and 7 females. The pathological diagnosis were fibrous dysplasia in 11 cases, simple bone cyst in 2 cases, aneurysmal bone cyst in 2 cases, benign fibrous histocytoma in 2 cases, giant cell tumor in 2 cases, and chondroblastoma in 1 case, including 3 pathological fractures. According to the Enneking staging system, 18 patients were in stage S1, 3 patients with pathological fractures in stage S2. There was no varus deformity or valgus deformity. The operation time, intraoperative blood loss, and time of full weight-bearing were recorded. X-ray film and CT were used to observe the bone graft fusion and location of DHS. Complications were recorded. Visual analogue scale (VAS) and Musculoskeletal Tumor Society (MSTS) scoring were used to evaluate function of lower limbs.ResultsThe average operation time was 177.1 minutes (range, 110-265 minutes). The average intraoperative blood loss was 828.6 mL (range, 200-2 300 mL). There was superficial incision infection in 1 case, deep incision infection in 1 case, and hip discomfort in 1 case, respectively. All patients were followed up 6-63 months (mean, 27.4 months). The time of full weight-bearing was 2 days in 2 patients with giant cell tumor and 2 to 13 weeks with an average of 7.2 weeks in the other patients. At last follow-up, VAS and MSTS were 0.19±0.51 and 29.62±0.97 respectively, showing significant differences when compared with the values before operation (3.52±2.62 and 23.71±8.77) (t=5.565, P=0.000; t=–3.020, P=0.007 ). X-ray film showed the all bone grafts fusion with mean time of 8.2 months (range, 5-12 months). There was no pathological fracture of the femur, local tumor recurrence, chronic hip pain, dislocation, or femoral head necrosis during follow-up.ConclusionThe treatment of benign bone lesion of the proximal femur using DHS and intralesional curettage via Watson-Jones approach is a safe and effective method.
Objective To compare the efficacy and safety of dynamic hip screw (DHS) + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults. Methods PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure, SinoMed, Wanfang, and Chongqing VIP database were searched for the literature related to the comparison between DHS + anti-rotation screw and cannulated screw alone for femoral neck fracture in adults from the establishment of databases to 2022. RevMan 5.3 software was used for meta-analysis. Results Finally, 25 clinical studies were included, including 8 randomized controlled trials and 17 observational studies, 5 in English and 20 in Chinese. There were a total of 2099 patients, including 989 in the DHS + anti-rotation screw group and 1110 in the cannulated screw group. The meta-analysis results showed that the incidence of bone nonunion [odds ratio (OR)=0.29, 95% confidence interval (CI) (0.17, 0.48)], incidence of femoral head necrosis [OR=0.48, 95% CI (0.27, 0.88)], failure rate of internal fixation [OR=0.28, 95% CI (0.15, 0.51)] in the DHS + anti-rotation screw group were lower than those in the cannulated screw group (P<0.05). The surgical duration [mean difference (MD)=9.91, 95% CI (6.78, 13.05)], incision length [MD=1.25, 95% CI (0.15, 2.35)], and Harris score [MD=6.77, 95% CI (4.66, 8.88)] in the DHS + anti-rotation screw group were higher than those in the cannulated screw group (P<0.05). There was no statistically significant difference in intraoperative bleeding volume, Visual Analogue Scale score, hospital stay, and fracture healing time between the two groups (P>0.05). The incidence of bone nonunion in the DHS + anti-rotation screw group after Pauwels type Ⅲ fracture [OR=0.16, 95% CI (0.05, 0.50)] was lower than that in the cannulated screw group (P<0.05), and there was no statistically significant difference in the incidence of femoral head necrosis between the two groups (P>0.05). Conclusions For femoral neck fracture in adults, DHS + anti-rotation screw can reduce the incidence of bone nonunion, femoral head necrosis, and internal fixation failure compared with cannulated screw alone, and has a higher Harris score, but the surgical duration and incision are longer. Overall, DHS + anti-rotation screw are better at reducing the incidence of complications than cannulated screws alone.