【Abstract】 Objective To disscuss the therapeutic method of the postoperative infection after hip arthroplasty andcompare the results of one-stage revision and two-stage revision. Methods From January 1999 to December 2005, 15 casesof infection after hip arthroplasty were treated, including 10 males and 5 females, with a mean age of 63 years (54-71 years).The locations were left hip in 8 cases and right hip in 7 cases. The first operation was hip prosthesis replacement in 6 cases andtatol hip arthroplasty in 9 cases. Infection occurred after 1 month in 6 cases and after 6 months in 9 cases. The preoperativetemperature and ruting blood test were normal, the mean erythrocyte sedimentation rate(ESR) was 61 mm/h (34-80 mm/h),mean C-reactive protein(CRP) was 11.7 mg/L(5.4-21.0 mg/L). The mean Harris score was 33 (25 - 40). The X-ray films showedthat periosteal reaction, osteolysis and loosening of prosthesis occurred. The time from the first operation to revision operationwas 1-41 months (mean 7.3 months). The results of bacterial culture were positive in 11 cases. One-stage revision wasperformed in 10 ases, two-stage revision was performed in 5 cases. Results Of 15 cases, 6 were classified as early postoperativeinfection, 9 cases as late chonic infection. The microorganism cultures results of joint aspiration or pus in sinus werepositive in 11 cases and negative in 4 cases before operation and during operation; 8 had staphylococcus epidermids infection,2 escherichia col i infection and 1 staphylococcus aureus infection. Incision of revision operation healed by first ention. Nore-infection, swell ing and tenderness occurred after 19 months (12-37 months) of follow-up. Pain of hip joint disappeared in14 cases, and only 1 case had mild pain when walking. ESR and CRP after operation decreased to normal range. The mean Harrisscore increased significantly to 84.2(79-92) after revision, showing significant difference when compared with that beforeoperation (P ＜ 0.05). Conclusion For postoperative infection after total hip arthroplasty, it is still possible to have satisfactorycl inical outcome by one-stage or two-stage revision as long as clear diaglosis and correct treatment can made.【Key words】 Hip arthroplasty Postoperative compl ications Infection Revision operation
Objective To investigate the rotational mismatch of total kneereplacement with medial 1/3 of tibial tuberosity as bony landmark in osteoarthritic patients with varus or valgus deformity. Methods Axial images on computed tomography of 62 knees (including 55 varus deformities and 7 valgus deformities) in 32 Chinese osteoarthritic patients who had total knee arthroplasty were analyzed, compared with that of 10 healthy knees. On images of the distal femur, the angle between the lines of surgical epicondylar axis(SEA) and posterior condylar axis was measured as posterior condylar angle (PCA), and on images of the proximal tibia, a baseline for the anteriorposterior axis of each component was drawn based on the SEA for the femur and the medial 1/3 of the tibial tuberosity for the tibia. The angle between these lines (Angle α) was defined as therotational mismatch between the components when they were aligned to the anatomic landmarks of each bone. Results The sulcus of medial epicondyle of femur could be identified on CT images of over 80% osteoarthritic knees; the median value of PCA was +2.36°, with an individual variation of 0° to +7.5°. Angle α was +6.45±3.68°(range, 0° to +11.8°) in 10 healthy knees, which increased significantly to +10.85±10.47°(range, 0° to +28.1°)in 55 varus knees (P＜0.05), which also increased significantly to +11.6±7.3°(range, -6.5° to +26.8°) in 7 valgus knees (P＜ 0.05). Conclusion With the medial 1/3 of the tibial tuberosity as the rotational landmark for the tibial component, there was a tendency to align the tibial component in external rotational position relative to the femoral component in knees with normal alignment, the rotational mismatch increased in Chinese osteoarthritic knees with varus and valgus deformity.
Objective To evaluate the clinical results of bioabsorbable interference screw in knee ligament reconstruction. Methods From April 2002 to August 2004, 39 patients with knee ligament injury were treated, including 33 males and6 females with a median age of 25 years (15 to 65 years). The involved ligament included 29 anterior cruciate ligament of knee(ACL), 6 posterior cruciate ligament of knee(PCL)，4 combined ACL and PCL, 3 medial collateral or lateral collateral ligaments of knee point and 1 posterolateral complex injury of knee. All of patients underwent anatomic ligament reconstructions under arthroscopy or open surgery by autografts and fixation with bioabsorbable interference screw. Results All 34 patients were followed up 6 to 28 months (mean 13.7months). The patients were evaluated by Lysholm knee functional scales, the knee scores were 43.6±13.4 before operation and 85.4±16.3 after operation, showing significant difference (Plt;0.05). There was no limitation of rangeof motion and loosening of the screw. However, one case suffered from infection, and 3 cases suffered from effusion and synovitis after surgery and recovered after management. Conclusion Bioabsorbable interference screw fixation is a reliable method in knee ligament reconstruction and is effective to restore knee joint stability.
Objective To analyze the relationship between the collateral ligament attachment and the epicondylar axis with rotational alignment of the femoral component in the total knee arthroplasty(TKA).Methods Twenty normal cadaver knee joints were anatomized and 2 holes were drilled on the distal femur from the deep and superficial insertions of the medial collateral ligaments to the lateral condylar part, respectively. Then, all the knees were scanned by MRI on the sagittal plane, making the drilled hole located relatively to the posterior condylar joint surface on the axial plane, and the posterior condylar angle (PCA) and thecondylar twist angle (CTA) were measured.Results The colateral ligament had the deep and superficial parts, and the deep part was strained during the knee flexing. PCA and CTA were 4.50±1.26° and 7.10±0.30° respectively, and there was a significant difference between them(P＜0.05), which were significantly greater than those reported abroad. On the sagittal plane, there wasno significant difference between the radiuses of the posterior medial and lateral condylar circles (Pgt;0.05). The distance from the center of the posterior condylar circle to the deep insertion of the medial collateral ligament (MCL) (d1) was 4.22±0.20 mm, and the distance to the superficial insertionof MCL (d2) was 7.36±0.13 mm. The difference between d1 and d2 was significant(Plt;0.05). Conclusion The center of the posterior condylar circle passes from the deep insertion of the collateral ligament, which can be regarded as a fixed flexionextension axis of the knee. By releasing the different parts of the collateral ligaments, the balance of the flexion and extension gap canbe obtained, and then varus, valgus or flexed contracture deformity of the kneecan be realigned. Besides, the rotational orientation of the femoral prothesis can be made by a reference to the epicondylar insertion of the collateral ligament.