Objective To investigate the early-term effectiveness of extra-large uncemented acetabular components for hip revision in the treatment of extensive acetabular bone defect. Methods Between September 2008 and May 2012, 13 patients (13 hips) with extensive acetabular bone defect underwent first hip revision using extra-large uncemented acetabular components (Jumbo cup). The diameter of Jumbo cup was larger than or equal to 64 mm for male and 60 mm for female. There were 4 males and 9 females with an average age of 64.7 years (range, 58-84 years). The period from primary arthroplasty to revision was 3-16 years (mean, 9.6 years). According to Paprosky classification, acetabular bone defect was rated as stage IIA in 2 cases, as stage IIB in 5 cases, as stage IIC in 4 cases, and as stage IIIA in 2 cases. The preoperative vertical distance from the center of involved femoral head to interteardrop line was (21.2 ± 6.1) mm longer than that of normal side. The Harris score and the rotation center of hip were evaluated preoperatively and postoperatively. Results Healing of incision by first intention was obtained in all patients, and no complication of dislocation, infection, and injury of sciatic nerve or femoral nerve occurred. The duration of follow-up ranged from 13 to 40 months (mean, 23.5 months). Partial or complete pain relief was achieved in all patients. The other patients could walk independently and restored to their routine jobs except for 1 case of hemiplegia caused by acute cerebral infarction at 3 months after surgery. In 5 patients with bone implantation, with the prolonging follow-up, the allograft could integrate with the host bone without absorption, and the bone fusion time was 9-35 months (mean, 14.5 months). At last follow-up, the X-ray films revealed that the vertical distance from the center of involved femoral head to interteardrop line was (6.0 ± 3.1) mm longer than that of normal side, which was significantly reduced when compared with preoperative value (t=11.13, P=0.00). No periprosthetic transparent region, prosthesis displacement, or screw breakage occurred. The Harris score was significantly increased from 30.4 ± 8.8 preoperatively to 85.1 ± 3.2 at last follow-up (t=22.11, P=0.00). Conclusion The application of extra-large uncemented acetabular components could be an effective technique for the reconstruction of extensive acetabular bone defect, and gain a good early-term effectiveness. The long-term survival rate of prostheses needs to be followed up.
Objective To observe the tendency of serum cobalt (Co), chromium (Cr), and molybdenum (Mo) ions concentration level after resurfacing arthroplasty of the hip (RSAH) by inductively coupled plasma mass spectrometer (ICP-MS), and analyze the influence factors. Methods Forty-seven patients (55 hips) underwent RSAH between June 2005 and November 2014 who had good joint function (Harris score were >85) at every review time were selected in the study. There were 25 males and 22 females, with the mean age of 49.7 years (range, 18-64 years). The disease causes included developmental dysplasia of the hip (DDH) in 18 cases (22 hips) and non-DDH in 29 cases (33 hips). The follow-up time was 6 months to 5 years (mean, 3.2 years). The concentrations of Co, Cr, and Mo ions were measured by ICP-MS, and were compared with those of 6 normal controls. Based on the analysis of the measured results, patients were chosen and grouped according to prosthesis position and femoral head prosthesis diameter. A correlative analysis was made between serum metal ions concentration and various factors (age, body mass index, pre- and post-operative Harris scores, neck-shaft angle, and stem-shaft angle). Results The concentration of serum Co ion reached the peak at 1 year after operation (P<0.05), and then slowly decreased, increased again at 4 years after operation and was close to the 2nd-year level at 5 years. The concentration of serum Cr ion reached its peak at 9 months after operation (P<0.05), and then gradually decreased, and was close to normal level at 5 years. The concentration of serum Mo ion kept increase trend and reached the peak at 5 years (P<0.05). Thirty-five hips of 29 patients followed up 9 months and 1 year were grouped. For DDH and non-DDH patients, Co and Cr ion concentrations of 40-45° abduction angle of acetabular component were significantly lower than those of <40 and="">45° (P<0.05), but there was no significant difference in Mo ion concentration (P>0.05). For all patients, Co, Cr, and Mo ion concentrations of 15-20° anteversion angle of acetabular component were significantly lower than those of <15 and="">20° (P<0.05). Co, Cr, and Mo ion concentrations of ≥48 mm diameter of the femoral component were significantly lower than those of <48 mm (P<0.05). There was a negative correlation between Co ion and postoperative Harris score (r=–0.486,P=0.041). Conclusion The serum Co and Cr ions concentrations increase obviously at 1 year and 9 months after RSAH operation, and Mo ion concentration displays an increase trend. The metal ions concentrations have close relationship with the position of acetabular component.