Multivariate analysis of varus after Oxford unicompartmental knee arthroplasty / 北京大学学报(医学版)

OBJECTIVE@#To analyze the preoperative influencing factors of varus after Oxford unicompartmental knee arthroplasty.@*METHODS@#A total of 660 patients (767 knees) undergoing Oxford unicompartmental knee arthroplasty in adult joint reconstruction surgery department of Beijing Jishuitan Hospital from January 2018 to December 2019 were retrospectively analyzed. Inclusive criteria: diagnosis was osteoarthritis, single compartment lesions in the medial side of the knee; preoperative flexion deformity was less than 10°, active range of motion was greater than 90°; preoperative X-ray full-length images of both lower limbs showed less than 15° varus (Noyes method); anterior cruciate ligament was well functioned, The cartilage of lateral compartment of knee joint was intact.@*EXCLUSION CRITERIA@#combined with other inflammatory arthropathy; combined with extraarticular deformity; previous knee surgery history. The average age of the patients was (64.4±8.1) years, including 153 males and 497 females. The degree of post-operative varus was measured with Noyes method. The total patients were divided into varus group (Noyes≥3 °) and normal group (Noyes < 3 °). Gender, age, body mass index (BMI), range of motion (ROM), preoperative flexion deformity (FD), American Knee Society pain score (AKS) and American Knee Society function score (AKS function) were recorded. The standard anteroposterior and lateral X-ray films of knee joint and full-length lower extremity kinematic line films were taken by Sonialvision Safine Ⅱ (Shimadzu, Japan) multi-function digital tomography system. The image was measured by picture archiving and communication system (PACS). The following angles were measured preoperative Noyes angle, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA) and joint line converge angle (JLCA) were measured and analyzed.@*RESULTS@#Gender(P=0.346), operative side (P=0.619), age (P=0.746), BMI (P=0.142), preoperative ROM (P=0.102), preoperative knee pain score (P=0.131) and functional score (P=0.098) were not risk factors for postoperative varus. The influencing factors of postoperative varus were preoperative MPTA < 84 ° (P= 0.018, OR= 3.712, 95%CI: 1.250-11.027), preoperative Noyes > 5°(P=0.000, OR= 3.105, 95%CI: 1.835-5.254), preoperative FD > 5° (P= 0.001, OR=1.976, 95%CI: 1.326-3.234). Pre-operative LDFA (P=0.146) and preoperative JLCA (P= 0.709) had no significant effect on postoperative kinematic line.@*CONCLUSION@#Patients with severe preoperative varus, especially those with varus deformity mainly from the tibial side, and those with preoperative flexion deformity are more prone to get varus lower extremity kinematic line after Oxford unicompartmental knee arthroplasty.

Effect of Joint Line Elevation after Posterior-stabilized and Cruciate-retaining Total Knee Arthroplasty on Clinical Function and Kinematics / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Joint line (JL) is a very important factor for total knee arthroplasty (TKA) to restore. The objective of this study was to evaluate the early clinical and kinematic results of TKAs with posterior-stabilized (PS) or cruciate retaining (CR) implants in which the JL was elevated postoperatively.</p><p><b>METHODS</b>Data were collected from patients who underwent TKA in our department between April 2011 and April 2014. The patients were divided into two groups based on the prosthesis they received (PS or CR). At 1-year postoperatively, clinical outcomes were evaluated by the American Knee Society (AKS) knee score, AKS function score, and patella score. In vivo kinematic analysis after TKA was performed on all patients and a previously validated three-dimensional to two-dimensional image registration technique was used to obtain the kinematic data. Anteroposterior (AP) translation of the medial and lateral femoral condyles, and axial rotation relative to the tibial plateau, were analyzed. The data were assessed using the Mann-Whitney test.</p><p><b>RESULTS</b>At time of follow-up, there were differences in the AKS knee scores (P = 0.005), AKS function scores (P = 0.025), patella scores (P = 0.015), and postoperative range of motions (P = 0.004) between the PS group and the CR group. In the PS group, the magnitude of AP translation for the medial and lateral condyle was 4.9 ± 3.0 mm and 12.8 ± 3.3 mm, respectively. Axial rotation of the tibial component relative to the femoral component was 12.9 ± 4.5°. In the CR group, the magnitude of AP translation for the medial and lateral condyle was 4.3 ± 3.5 mm and 7.9 ± 4.2 mm, respectively. The axial rotation was 6.7 ± 5.9°. There were statistically different between PS group and CR group in kinematics postoperatively.</p><p><b>CONCLUSION</b>Our results demonstrate that postoperative JL elevation had more adverse effects on the clinical and kinematic outcomes of CR TKAs than PS TKAs.</p>

Kinematic study on tibiofemoral joint after TKA using 2D-3D automatic registration technique / 医用生物力学

Objective To reconstruct the 3D motion of the knee joint after total knee arthroplasty (TKA) and measure the kinematics and the articular contacts between the posterior stabilized TKAs. Methods Sixteen knees undergoing TKAs were scanned by fluoroscopy. An algorithm of automatic registration was developed to match the 3D TKA models and 2D images. The kinematical parameters and articular contact of the tibiofemoral joint was investigated. ResultsThe time for a single image was less than 30 seconds. The in-plane repeatability was within 0.4 mm and 0.5 degree. The application of the high-flex insert didn’t obviously improve the ability of the flexion and the internal/external tibial rotation. When the knee flexed, the contact point on the lateral side moved more posteriorly than that on the medial side. The contact between the post-cam and the femoral prosthesis occurred with the flexion at about 30 degrees. The average range of the contact was within 9 mm. Conclusions The 3D kinematics of the in vivo TKA knee joint was accurately measured by using 2D-3D automatic registration technique. The result can provide references for the biomechanical study of TKA knees and the improvement of TKA prosthesis design.

Influence of the insert design on clinical results and kinematics of the knee after total knee arthroplasty / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the influence of the insert design of knee prosthesis on clinical results and kinematics of the knee after total knee arthroplasty (TKA).</p><p><b>METHODS</b>Forty-two knees in 28 patients with knee osteoarthritis undergoing TKA using the GENESIS II from July 2007 to June 2009 were included in this study, mean follow-up of 27.7 months. The cases were divided into 2 groups according to the type of insert, one was high flexion insert group (23 knees) and the other was standard insert group (19 knees). Two groups were compared by clinical ratings of knee function. The motion of flexion and extension of the two groups was observed by cyclic fluoroscopy and the data was analyzed by mapping software. The influence of the insert design of knee prosthesis on kinematics of the knee after TKA was investigated by comparing the parameters of the two groups during the movement of knee joint, including femoral roll back and extensor mechanism arm.</p><p><b>RESULTS</b>The range of motion of standard insert group and high flexion insert group was 120° and 123° respectively with no difference between them. There was no difference of knee society clinical rating system in both groups. Feller score of high flexion insert group was higher than the standard insert group, the difference was significant statistically (P = 0.012). In the imaging measurement, the two groups had no differences in femoral rollback and extensor mechanism arm during the 0 to 120° range of movement. The two groups appeared significant statistically (P = 0.034) in the extensor mechanism arm when flexion extended to 130°.</p><p><b>CONCLUSIONS</b>The high flexion improved design may play a certain role on reducing anterior knee pain and improving knee function after TKA. However, the improved design may be reduced the extensor mechanism arm when high flexion, so that affecting the work ability of quadriceps.</p>

Radiographic appraisal between metal and bone interosculate backfill after total hip arthroplasty with trabecular metal cup / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the bone refilling in the interface between the trabecular metal (TM) acetabular shell and the bone surface according to consecutive X film measuring after surgery.</p><p><b>METHODS</b>From July 2006 to July 2007, 35 patients (40 hips) accepted total hip replacement using trabecular metal monoblock acetabular cup system (TM). The cup was made of a ellipse shaped press fit Tantalum shell and high cross-linked PE liner (Longevity) with 28 mm inner diameter. The patients demography was: 16 male (20 hips), 19 female (20 hips), 5 bilateral hip replacements, age from 41 - 71 (mean 53), including 18 avascular necrosis hips, 16 osteoarthritis hips (including those secondary to a dysplasia hip), 4 avascular necrosis hips after femoral neck fracture, 2 Ankylosis Spondylitis. All the 40 total hip replacements used posterior approach, using hemispherical acetabular reamer and 2 mm press fit of final metal shell without screw fixation. The consecutive X film was taken at the end time of surgery and 2, 6, 12, 24 weeks, and 12 months. The clinical results was evaluate according to Harris scoring system, and the standard pelvis AP X film was measured at the interface between metal shell and the acetabular bone surface, witch was divided into five regions (A, B, C, D, E).</p><p><b>RESULTS</b>Totally 32 patients (37 hips) were followed with average 8.7 months (7 - 12 months). The Harris before surgery was 50.5 (32 - 85), promoted to 91.0 (72 - 100), including 29 excellent, 6 good, 2 fair, and the total excellent and good rate was 94.6%. Complications include 4 patients leg length discrepancy from 1 - 2 cm, 3 patients moderate thigh pain and released after conservative therapy. No infection and dislocation was found. Twenty-one patients (23 hips) were found lucent line at the bone-metal interface from 1 - 5 mm, most common in B region and BC boundary than C, D, and CD boundary. All the patients followed was found the lucent line disappeared and refilled with bone at X film 24 weeks after surgery, however, no patients was found osteolysis and cup migration.</p><p><b>CONCLUSION</b>The trabecular metal has strong capacity of bone conductive and bone inducement.</p>