Many complications after operative treatment of patella including redisplacement of fracture, refracture, weakness of extensor muscles, patellofemoral joint arthritis, metal failure, malunion, infection, avascular necrosis were reported. We report a case of transverse fracture of patella through the cannulated screw fixation site used to fix previous vertical patella fracture with a review of the literatures.
Arthritis ; Muscles ; Necrosis ; Patella* ; Patellofemoral Joint

PURPOSE: This research was conducted to compare supine and standing Merchant views, to observe radiographic changes of the patellofemoral joint according to weight-bearing conditions, and to evaluate correlation factors affecting patellofemoral joint indices. MATERIALS AND METHODS: Forty-four patients without skeletal problems were selected for this study. Patellar tilt angle, lateral patellofemoral angle, congruence angle, lateral subluxation distance and lateral patellar displacement were measured on each radiograph and evaluated for statistical significance. Possible correlation factors that can affect the radiographic discrepancy were analyzed using the univariate and multivariate regression analysis. RESULTS: In the standing Merchant view, the patellar tilt angle, congruence angle and lateral patellar displacement were significantly decreased (p<0.001), whereas the lateral patellofemoral angle was significantly increased (p<0.001) compared to that in the supine Merchant view. Thigh width (p<0.001, r2=0.22) and radiographic Q-angle (p<0.001, r2=0.34) were found correlated with the radiographic discrepancy of congruence angle. Discrepancy of the lateral patella displacement increased as radiographic Q-angle increased (p=0.027, r2=0.112). CONCLUSIONS: Compared with the supine Merchant view, standing (weight-bearing) Merchant view showed decreased patella tilt angle, congruence angle, and lateral patella displacement. The results indicate that both supine and standing Merchant views should be considered in the radiographic evaluation of the patellofemoral joint.
Humans ; Patella ; Patellofemoral Joint ; Thigh ; Weight-Bearing

PURPOSE: to find out the change and limit of the changes of tibiofemoral joint line, patellar position and other related variables for improved postoperative knee function after PCL retaining TKRA. MATERIALS AND METHODS: The variables mentioned above were measured from the plain radiographs of 101 knees with PCL retaining TKRAs, correlated with clinical outcomes such as HSS score, range of motion and anterior knee pain. Then they were analyzed statistically. RESULTS: Tibiofemoral joint line, patellar height and femoral condylar size affected clinical outcomes. Excellent postoperative knee function resulted when the shift of tibiofemoral joint line position was between 5mm inferiorly to 5mm superiorly, postoperative patellar height between 15mm to 30mm, and the change of the femoral condylar size between 10mm decrease and 5mm increase. CONCLUSION: Excellent clinical results would be expected if the changes of the joint line position are kept within the range suggested in this paper.
Joints ; Knee ; Knee Joint ; Patellofemoral Joint* ; Range of Motion, Articular

As modern medicine getting deeply to understand ever-detailed anatomy,structure and animal mechanics of the patellofemoral joint, excessive lateral pressure syndrome, a very common patellofemoral disorder, has been reacquainted by the clinicians. On account to the complexity and variety of the etiology and the mechanism of the pain, still, there are many difficulties and arguments on the exact description of the clinical symptoms and the establishment of a universally accepted diagnostic criteria. Accurately grasping different causes, pathomechanisms and developmental stages of the disease would be especially important. As a result, rational choice of the pertinent procedures become the clinical lynchpin. This paper reviews domestic and international pertinent literatures in the past 10 years, and provide an overview of the latest study of anatomy, biomechanic, pathomechanism and clinical experience, anticipating to offer help on standardizing the diagnosis and treatment of ELPS.
Humans ; Pain ; complications ; diagnosis ; Pain Management ; Patellofemoral Joint ; Pressure ; Syndrome

Anterior knee pain is an enigmatic entity with multiple causes, and so the patients, who present with diverse symptoms, require different treatments. A combination of variables, including abnormal lower limb biomechanics, soft-tissue tightness, muscle weakness and excessive exercise, may result in increased cartilage and subchondral bone stress, patellofemoral pain and subtle or more overt patellar maltracking. Because of the multiple forces affecting the patellofemoral joint, the clinical evaluation and treatment of this disorder is quite a challenge. Our extensive search of the literature revealed no single gold-standard test/maneuver to diagnose this disorder, and the reliability of the maneuvers described was generally low or untested. Making a specific and accurate diagnosis of the etiology, based on a thorough physical exam and imaging studies, is essential to create an effective therapeutic approach for the patient's successful return to proper knee function.
Biomechanics ; Cartilage ; Humans ; Knee ; Lower Extremity ; Muscle Tonus ; Patellofemoral Joint

PURPOSE: The purpose of this study were to evaluate the relationship between anterior knee pain and changes of patellofemoral joint in osteoarthritic knee. MATERIALS AND METHODS: We analyzed 200 patients who had undergone total knee arthroplasty and divided them into two groups ; the group 1(100 cases) with anterior knee pain and the group 2(100 cases) without it. We prospectively measured congruence angle and patellar height, and compared radiologic degenerative changes and operative findings(Outerbridge classification) of patella. RESULTS: The average congruence angle of patella was 11.2+/-1.6degrees in the group 1 and 2.8+/-1.3degrees in the group 2(p<0.05). Patellar height had no significant difference between two groups(p=0.62).For radiologic patellofemoral(PF) degenerative change, the group 1 showed mild degenerative change in 16 , moderate change in 47 and severe change in 37 in plain radiographs. The group 2 showed mild degenerative change in 53 and moderate change in 47 in plain radiographs(p<0.05). For cartilage degenerative change in patella(Outerbridge classification), whereas grade 3&4 were dominant in the group 1 with 71 cases, grade 1&2 were representative in the group 2 with 91 cases(p<0.05). CONCLUSION: Anterior knee pain seemed to be related with congruence angle and degenerative changes in radiologic and operative findings.
Arthroplasty ; Cartilage ; Humans ; Knee* ; Osteoarthritis* ; Patella ; Patellofemoral Joint ; Prospective Studies

PURPOSE: To evaluate the clinical and radiologic results in patients with total knee arthroplasty without patellar resur- facing. Subject and Method: In this study, 64 cases of total knee arthroplasty without patellar resurfacing were performed nonselectively by a single surgeon from January 2000 to January 2004, and followed up for more than 2 years(range, 24~72 months). The clinical results according to Hospital for Special Surgery knee score and Feller's patellar score, and radiological evaluations about patellar subluxation were analyzed for the correlation of the two results. RESULT: HSS score improved from 54 to 83 points, and Feller's patellar score improved from 18 to 27 after surgery. In preoperative radiologic evaluation, 61 cases(95.3%) were assessed as 'open laterally', the average patellofemoral index was 1.4(0.6~2.5) and the lateral patellar displacement was 1.2mm. In the latest follow-up, 56 cases(87.5%) were assessed as 'open laterally', the average patellofemoral index was 1.5(0.5~3) and the lateral patellar displacement was 1.5(0~8)mm. In comparison between the clinical and radiologic results, no statistic significance was noted in their correlation(p>0.05). CONCLUSION: Total knee arthroplasty without patellar resurfacing was performed nonselectively, satisfactory clinical outcome was observed despite radiologic changes such as patellar subluxation and displacement. It was considered that there was no significance in correlation between radiological changes and clinical results.
Arthroplasty* ; Follow-Up Studies ; Humans ; Knee* ; Patella* ; Patellofemoral Joint

The displacement of patellar components, such as dislocation or subluxation, causes polyethylene wear and further induces metallosis of the metal-backed patella. We compared two different patellar components, onset(Miller-Galante I) and inset(Whiteside-Ortholoc I)type, to understand the differences in patellar tracking according to their designs. Patellar prosthesis position in 43 primary total knee arthroplasties was evaluated with patellar tilt, patellar displacement from the center of the trochlear groove, medial placement, patellar thickness, and joint line height. For the MG(Miller-Galante I)group, the patellar displacement was laterally 50.0% and for the Ortholoc group, it was 33.3%. In the MG group, 4 cases of revision of the patellar component due to excessive polyethylene wear were performed, but there was no excessive wear of polyethylene in Ortholoc group. One of the primary factors which influence tracking of the patellofemoral joint is the difference in design between the patellar component and the femoral component. But in the opinion of the authors, the slope or lateral displacement of the patellar component have no correlation with each other under radiological measurements. However, the inset-type patellar component is a design that maintains the bony flange within the lateral flange, therefore relieving the shear stress and rotational forces loaded on the patellofemoral joint and protecting the metal-backing from exposure. Thereby, even if dislocation or subluxation of the patellar component should occur, polyethylene wear or metallosis caused by excessive wearing can be minimal.
Arthroplasty* ; Dislocations ; Joints ; Knee* ; Patella ; Patellofemoral Joint ; Polyethylene ; Prostheses and Implants

PURPOSE: The purpose of this study was to analyze sex- and laterality-specific patellofemoral alignment using three-dimensional computed tomography (3D-CT) in normal Korean patients. MATERIALS AND METHODS: The study included 90 patients (45 men, 45 women; 180 knees) with no history of anterior knee pain or malalignment by physical examination. The mean patient age was 42.2 years (Range: 24~66 years). 3D-CT scanning was performed with each patient in the supine position with 15degrees of knee flexion. Patellofemoral joint alignment was evaluated by measuring the sulcus angle, congruence angle, lateral patellofemoral angle, condyle-patellar angle, and condyle-lateral angle. RESULTS: Comparing men and women, respectively, the sulcus angles were 145.9degrees+/-8.9 and 149.4degrees+/-9.7, the congruence angles were 12.6degrees+/-22.7 and 12.0degrees+/-19.6, the lateral patellofemoral angles were 9.9degrees+/-6.0 and 8.5degrees+/-4.3, the condyle-patellar angles (lateral facets) were 14.2degrees+/-7.1 and 11.8degrees+/-4.8, the condyle-patellar angles (patellar axes) were -8.5degrees+/-7.7 and -10.6degrees+/-6.1, and the condyle-lateral angles were 15.5degrees+/-7.6 and 16.4degrees+/-4.0. There was no significant difference in these measurements between left and right knees, but there was a significant difference in the sulcus angle and condyle-patellar angle between men and women (p<0.05). CONCLUSION: These data will hopefully serve as a basis for evaluating normal patellofemoral alignment and for diagnosing patellofemoral malalignment in Korean patients.
Female ; Humans ; Knee ; Male ; Patellofemoral Joint ; Physical Examination ; Supine Position

PURPOSE: The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). MATERIALS AND METHODS: MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. RESULTS: With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31. CONCLUSIONS: MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction.
Humans ; Knee ; Magnetic Resonance Imaging ; Patella ; Patellofemoral Joint ; Pathology