Co and Cr accumulation in hair after metal-on-metal hip resurfacing arthroplasty.

BACKGROUND: Currently, it is unclear whether Co and Cr levels are persistently elevated in the body after hip resurfacing arthroplasty (HRA). This study aimed to evaluate Co and Cr levels in the body after HRA using hair as samples. METHODS: Among 22 patients who had metal-on-metal HRA(m-o-m group) using the DePuy ASR system, scalp hair of 1.5 cm in length and 2 g in weight was collected before and at 6 and 12 months after surgery. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to detect Co and Cr levels in the scalp hair. Another 22 patients with total hip replacements were randomly selected from a similar age range as controls (m-o-p group). Metal levels in hair were detected with multiple measurements and analysed by repeated measures analysis of variance. RESULTS: Both Co and Cr levels were significantly increased in the m-o-m group after surgery compared with those in the m-o-p group (P < 0.01). Co levels at 6 months post-operatively were 12-fold those before surgery, and Co levels 12 months postoperatively were lower than those at 6 months, but this difference was not significant (P = 0.0805) between the two time points in the m-o-m group. Cr levels were persistently elevated after surgery and were increased by 10-fold compared with those at baseline in the m-o-m group. CONCLUSIONS: Co and Cr levels in scalp hair are ideal indicators for metal levels in the body after HRA. Co and Cr levels in the body were greatly increased after metal-on-metal HRA. Long-term accumulation of these metals needs to be further investigated

[The use of uncemented extensively porous-coated femoral components in the management of Vancouver type B2 periprosthetic femoral fractures].

OBJECTIVE: To assess the outcome of patients with Vancouver type B2 periprosthetic fractures treated with femoral revision using an uncemented extensively porous-coated implant. METHODS: From October 2002 to May 2007, a retrospective clinical and radiographic assessment of 10 patients with Vancouver type B2 periprosthetic fractures treated with femoral revision was evaluated, among which 4 was cement fixation, 6 was non-cement fixation in the index procedure. RESULTS: The mean follow-up for these patients was 44 months (range, 12 to 67 months). The mean Harris hip score was 87.6 points. All 10 reconstructions showed solid fracture union and a stable prosthesis, 8 was bone ingrowth, 2 was fibrous ingrowth. Complications in 4 patients included thigh pain in 1, stress shield in 3. CONCLUSIONS: Vancouver type B2 periprosthetic fractures treated with uncemented extensively porous-coated femoral stems incorporate distally allowing stable fixation.

[Effect of total hip replacement on lumbago in unilateral developmental hip dysplasia].

OBJECTIVE: To assess the effect of total hip replacement on lumbago in patients with unilaterally developmental hip dysplasia. METHODS: From January 2001 to January 2006, 39 adult patients with unilateral developmental hip dysplasia co-exiting lumbago were included. Among them, there were 32 females and 7 males, age from 38 years to 73 years. According to Crowe classification system, there were 4 in type I, 20 in type II,8 in type III and 7 in type IV. They were performed total hip replacement. The Harris Hip Score and the Oswestry Disability Index were used to evaluate hip and spine symptoms in same patient before and 3, 24 months after operation. RESULTS: Thirty-nine patients were evaluated, both hip and spinal pain and function were significant improved. The mean Harris score increased from 44 to 84 (P < 0.01). The mean Oswestry Scores dropped from 36 to 25 (P < 0.01). CONCLUSION: Spinal function and lumbago is improved after total hip replacement in patients with unilateral developmental hip dysplasia at 3 months, which is maintained and enhanced in 2 years.

[Patella reshaping versus resurfacing in total knee arthroplasty: a prospective randomized study].

OBJECTIVE: To investigate the differences in the clinical outcome of total knee arthroplasty according to patellar reshaping or resurfacing. METHODS: From January 2002 to December 2002, 60 patients (60 knees) undergoing primary total knee arthroplasty for the treatment of osteoarthritis were enrolled in a prospective, randomized study. All patients received the same posterior-cruciate-substituting total knee prosthetic components. Patients were randomized to the treatment with reshaping or resurfacing of the patella, and the results were followed up for a mean of 54 months (40-60 months). Evaluations consisted of the determination of a Knee Society Score, range of motion for knees, patient satisfaction, and radiographs. RESULTS: With the numbers available for study, no significant difference was found between the knees that had patellar resurfacing and those that had patellar reshaping with regard to the overall score (P=0.12), the subscore for pain (P=0.90), and patient satisfaction (P=0.22). The results showed that the same prevalence of any anterior knee pain in two groups was 10%, and it did not represent a significant difference. The two groups showed statistical difference with regard to the total function score and range of motion. CONCLUSIONS: It has shown that total knee arthroplasty with patella reshaping or resurfacing dramatically relieves pain and improves the function. It seems that postoperative anterior knee pain is related either to the component design or to the details of the surgical technique, rather than to whether or not the patella is resurfaced.

[The use of a closed-suction drain in total knee arthroplasty: a prospective, randomized study].

OBJECTIVE: To determine the value of using a closed-suction drain in cemented knee arthroplasty. METHODS: One hundred patients were prospectively randomized into two groups, one group underwent cemented total knee replacement with a single deep closed-suction drain, and the other group (n = 50) no drain. RESULTS: The total blood loss was significantly greater in those with a drain although those without lost more blood into the dressings. There was no statistical difference in the postoperative swelling or pain score, ecchymosis, deep vein thromboses (DVT), time at which flexion was regained or the incidence of infection at a minimum of two years after surgery in the two groups. CONCLUSION: There is no evidence to support the use of a closed-suction drain in cemented knee arthroplasty.

[The effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty].

OBJECTIVE: To study the effect of rotational alignment of the femoral components on the patellofemoral biomechanics in total knee arthroplasty (TKA) demonstrated on autopsy specimens, as the guide for surgeons to choose the correct reference axis for rotational alignment of the femoral components and to reduce the patellofemoral joint complications. METHODS: Select 9 frozen fresh human cadaver knees without gross deformities or instabilities and mount specimens on a patellofemoral joint testing jig connected to a Model 8501 Instron machine (Instron Corporation, Canton, MA). The study simulated the action of squatting from the standing position with the foot firmly planted. Standard TKA was performed in each specimen by the same senior surgeon using Nexgen LPS total knee system (Zimmer Corporation, Warsaw Indiana). Alter rotational alignment of the femoral components referenced to the transepicondylar axis and the Whiteside's line respectively. Measure biomechanics of the patellofemoral joints using Fuji prescale film at 30 degrees , 60 degrees , 90 degrees , 120 degrees of knee flexion respectively. The digital values were obtained by the handheld pressure measurement systems (FPD-305E, FPD-306E) and Autocad software. RESULTS: The rotational alignment of the femoral components paralleled to the transepicondylar axis had the best results of the peak value of the patellofemoral contact pressure (P < 0.05). There were no statistically significant differences in patellofemoral contact area (P > 0.05). But the patellofemoral contact area had the close correlations to the angles of the knee flexion and the specimens. CONCLUSIONS: Rotational alignment of the femoral components has a great influence on the patellofemoral contact pressure in total knee arthroplasty. It is reliable for surgeons to choose the transepicondylar axis as the reference axis to rotate femoral components.