Osteoid osteoma is very rarely located in the patella, and can represent a significant diagnostic challenge, resulting in a delay of treatment. Patients with osteoid osteoma of the patella often present with knee pain that is also a typical symptom of trauma or of other diseases such as arthritis, which are much more common than osteoid osteoma. We present two young male patients diagnosed with osteoid osteoma of the patella. Each of these patients had a history of intense knee pain; however, accurate diagnosis of osteoid osteoma in the patella had been delayed for more than one year. Computed tomography (CT) scans or magnetic resonance imaging (MRI) showed a circumscribed lesion of the patella in both patients, whereas X-ray examination (posteroanterior projection) was not able to detect the tumor. Different surgical procedures were performed in these patients for resection of the tumors, and the pathology findings confirmed the diagnosis of osteoid osteoma. Both patients recovered completely from surgery.
Adolescent ; Adult ; Humans ; Male ; Osteoma, Osteoid ; diagnosis ; diagnostic imaging ; surgery ; Patella ; diagnostic imaging ; pathology ; surgery ; Radiography

Adolescent ; Diagnosis, Differential ; Humans ; Hyperoxaluria, Primary ; diagnosis ; Knee ; diagnostic imaging ; Lumbar Vertebrae ; diagnostic imaging ; Male ; Patella ; diagnostic imaging ; injuries ; Radiography

OBJECTIVETo reveal the possible mechanism involved in patella-femoral degenerative arthritis (PFDA) in- duced by torsion-deformity of tibia via analyzing the relationship between torsion-deformity of the tibia in patients with PFDA and the disorder of patella-femoral joint under the static and dynamic conditions.

METHODSFrom October 2009 to October 2010, 50 patients (86 knees, 24 knees of male patients and 62 knees of female patients) with PFDA were classified as disease group and 16 people (23 knees, 7 knees of males and 16 knees of females) in the control group. The follow indexes were measured: the torsion-angle of tibia on CT scanning imagings, the patella-femoral congruence angle and lateral patella-femoral angle under static and dynamic conditions when the knee bent at 30 degrees of flexion. Based on the measurement results, the relationship between the torsion-deformity of tibias and the disorders of patella-femoral joints in patients with PFDA were analyzed. Finally,the patients were divided into three groups including large torsion-angle group, small torsion-angle group and normal group according to the size of torsion-angle, in order to analyze the relationship between torsion-deformity and disorders of patella-femoral joint, especially under the dynamic conditions.

RESULTSCompared with patients without PFDA, the ones with PFDA had bigger torsion-angle (30.30 ± 7.11)° of tibia, larger patella-femoral congruence angle (13.20 ± 3.94)° and smaller lateral patella-femoral angle (12.30 ± 3.04)°. The congruence angle and lateral patella-femoral angle under static and dynamic conditions had statistical differences respectively in both too-big torsion-angle group and too-small torsion-angle group. The congruence angle and lateral patella-femoral angle under static and dynamic conditions had no statistical differences in normal torsion-angle group.

CONCLUSIONTorsion-deformity of tibia is the main reason for disorder of patella-femoral joint in the patients with PFDA. Torsion-deformity of tibia is always accompanied by instability of patella-femoral joint,especially under the dynamic condition, thus causing PFDA. It can not only provide arrangement information and degenerative condition of patella-femoral joint,but also provide guidance through the analysis on the relationship for better clinical prevention and early treatment of degenerative bone and joint disease.

Adult ; Female ; Femur ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Osteoarthritis, Knee ; diagnostic imaging ; etiology ; Patella ; diagnostic imaging ; Radiography ; Tibia ; diagnostic imaging ; Torsion Abnormality ; complications ; diagnostic imaging

Fracture Fixation, Internal ; methods ; standards ; Fractures, Bone ; diagnostic imaging ; surgery ; Humans ; Knee Injuries ; diagnostic imaging ; surgery ; Patella ; injuries ; surgery ; Radiography

Objective To estimate sex based on patella measurements of Sichuan Han population by computed tomography three-dimensional volume reconstruction technique, and to explore the application value of patella in sex estimation. Methods CT three-dimensional volume reconstruction images of patella of 250 individuals were collected, the four measurement indicators including patellar length, patellar width, patellar thickness, and patellar volume were measured. The t-test was used to determine measurement indicators with sex differences. Fisher discriminant analysis was used to establish the sex discriminant function and the prediction accuracy was calculated by leave-one-out cross validation. Results The sex differences of the four measurement indicators had a statistical significance （P<0.05）. The accuracy rate of the univariate discriminant function established by the patellar length was the highest （82.0%）. The accuracy rates of the all indicators discriminant function and the stepwise discriminant function were 80.4% and 81.6%, respectively. Conclusion It is feasible and accurate to estimate sex of Sichuan Han population by patella measurements with CT three-dimensional volume reconstruction technique. The method may be used as an alternative for sex estimation of Sichuan Han population when other bones with higher accuracy are not available.
Discriminant Analysis ; Female ; Forensic Anthropology ; Humans ; Imaging, Three-Dimensional ; Male ; Patella/diagnostic imaging* ; Sex Determination by Skeleton ; Tomography, X-Ray Computed

A 20-year-old National Serviceman presented with left knee pain and swelling after training for his physical fitness test. Lateral knee radiography and magnetic resonance (MR) imaging showed patellar tendon-lateral femoral condyle friction syndrome (PT-LFCFS), on a background of patella alta and patellar malalignment. The patient was treated non-operatively with a course of physiotherapy and given advice on rest and activity modification. PT-LFCFS is a less well-recognised but important cause of anterior knee pain and represents an entity in a spectrum of disorders related to patellofemoral instability. We herein discuss the MR imaging findings specific to and associated with this condition, as well as briefly describing treatment options. In addition, we showcase a range of commonly encountered abnormalities that affect the infrapatellar fat pad and briefly discuss their specific MR imaging findings.
Adult ; Arthralgia ; diagnostic imaging ; Female ; Femur ; diagnostic imaging ; Humans ; Knee ; diagnostic imaging ; Knee Injuries ; diagnostic imaging ; therapy ; Knee Joint ; diagnostic imaging ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pain ; diagnostic imaging ; Patella ; diagnostic imaging ; Patellar Ligament ; diagnostic imaging ; Physical Therapy Modalities ; Radiography ; Young Adult

Breakage of K-wires and stainless steel wires which are used for fracture fixation is not uncommon, but migration is rare. We report a case of migration of broken K-wire used for patella tension band wiring to the popliteal fossa. The broken hardware was removed surgically. We would like to suggest that K-wire and wire fixation used for treatment of patellar fractures can migrate into the posterior compartment of the knee and cause clinical symptoms. Close clinical and radiological follow-up after internal fixation to identify the presence of hardware breakage or movement and removal of wires once fracture has united can avert such complications.
Adult ; Bone Wires ; Equipment Failure ; Foreign-Body Migration ; etiology ; Fracture Fixation, Internal ; instrumentation ; methods ; Fractures, Bone ; diagnostic imaging ; surgery ; Humans ; Male ; Patella ; diagnostic imaging ; injuries ; Radiography ; Time Factors

BACKGROUNDDue to racial differences in the morphology of the knee joint and due to most prostheses available in the market being designed using measurements from Caucasians, the objective of this study was to provide the morphometric data of the patella for the southern Chinese population for total knee arthroplasty (TKA), patellar resurfacing, and prostheses design.

METHODSThe CT slices of the knee joint were obtained from both knees of 40 Chinese volunteers (20 females, 20 males, and age from 20-25 years) by performing a computer tomographic scan. A 3D model was reconstructed by Mimics software based on the computed tomography images. Six metrical characteristics were measured by digital ruler. Statistical analysis was performed with the SPSS statistical program.

RESULTSThe mean, standard deviation and P values of measurements and ratios were calculated using SPSS. All dimensions showed a significant gender difference with P < 0.05, but the six variables of the left and right knees had no statistical significance with P > 0.05. In addition, we studied the relationship between six couples (H-W, H-T, H-HAF, W-T, W-HAF, T-HAF) of the four variables (H: height, W: width, T: thickness and HAF: height of articulating facet) that were measured, which showed a significant correlation.

CONCLUSIONSExamination of the southern Chinese population revealed that males have larger patellae than women. In both genders, comparing data between left and right knees shows no statistically significant difference. Compared with Westerners in previous studies, the patella in our study was thin and small. There was a good linear regression correlation between measurements of the patella. The indirect measurement method on 3D models makes it easy to obtain anatomical data, and the results can provide a region and gender specific database for morphometric measurements of the patella, and can be helpful for designing implants suited for southern Chinese patients.

Adult ; Arthroplasty, Replacement, Knee ; China ; Female ; Humans ; Male ; Patella ; diagnostic imaging ; Tomography, X-Ray Computed ; Young Adult

Adolescent ; Bone Plates ; Fracture Fixation, Internal ; instrumentation ; Fractures, Bone ; diagnostic imaging ; pathology ; physiopathology ; surgery ; Humans ; Male ; Patella ; injuries ; surgery ; Radiography

OBJECTIVE: To construct a dynamic knee joint finite element model based on CT image data and verify the validity of the model. To provide a simulation model and basic data for biomechanical research of the knee joint by further finite element analysis. METHODS: The CT data of a healthy male knee joint was selected. With the help of Mimics 19.0 and Hypermesh 12.0 software, a high simulation finite element model of knee joint was established following steps, including geometric reconstruction, reverse engineering, meshing and material characterization. The dynamic knee flexion model was generated by determining the boundary conditions and torque loading, and the validity of themodel was confirmed. The biomechanical changes of the tibiofemoral and patellofemoral joints under different knee flexion angles were analyzed by applying the loads (500 N) to the finite element model during knee flexion. RESULTS: A finite element model of knee joint was established based on CT images and anatomical characteristics. The model included three-dimensional elements such as bone, ligament, cartilage, meniscus and patellar retinaculum. The different finite element models of knee flexion states were produced by applying different torques after establishing boundary conditions. According to equivalent conditions (knee flexion 30 degrees, quadriceps tendon under 200 N stretch), the peak stress value of patella was 2.209 MPa and the average Mises stress was 1.132 MPa; the peak stress value of femoral trochlear was 1.405 MPa and the average Mises stress was 0.936 MPa. The validity of the model was proved by the difference between the model and previous studies of 1% to 13.5%. Dynamic model loading showed that the Mises stressof tibiofemoral joint decreased with the increase of knee flexion angle, while the Mises stress of patellofemoral joint was positively correlated with knee flexion angle. The Mises stress of cartilage stress planes at different knee flexion angles was significantly different(<0.05). CONCLUSION The finite element model established in this study is more comprehensive and can effectively simulate the biomechanical characteristics of dynamic knee joint, which provides support for further simulation mechanics researches of the knee joint.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Knee Joint ; diagnostic imaging ; Male ; Patella ; Stress, Mechanical ; Tomography, X-Ray Computed