MATERIALS AND METHODS: A retrospective study of patients diagnosed as benign bone tumours according to the Enneking classification who underwent simple or extended curettage at Menoufia university-Orthopedic Oncology Division (with or without grafting or filling) during the surgical treatment (Jan 2015 to Feb 2020). A review of the medical records was done. Lesions' size (length, width and depth) was measured on plain radiographs using the image j program. When applicable, degrees of filling of the resultant cavity were classified into four categories, according to Modified Neer's classification. Functional evaluation using the musculoskeletal tumour society (MSTS) score was reviewed.

RESULTS: Overall, 88 patients diagnosed with a primary bone tumour and who received the surgical intervention were included in the study. The mean age of the patients was 22.61+13.497 (3-58) years. There were 48 males and 40 females (54 right and 34 left). The mean follow-up period was 28.09+16.13 months. The most common location was the distal femur in 15 patients, the proximal femur in 10 patients and the proximal tibia in 12 patients. The most common diagnosis was giant cell tumour in 20 patients, followed by UBC in 19 patients, ABC in 15 patients and enchondroma in 13 patients. Twenty-three patients had simple curettage, while 65 patients had extended curettage. Mean MSTS was 28.78±1.68. Fifty-five lesions were classified according to modified Neer's classification.Thirtty-two patients were classified as type 1 with complete healing,22 patient was classified as type 2 with partial healing, and only one was classified as a recurrent lesion. Seven patients (7.9%) developed local recurrences.

METHODS: Three different cams (triangle, ellipse, and circle) and three different posts (straight, convex, concave) geometries were considered in this study and were analysed using kinematic analyses. Femoral rollback did not occur until reaching 50° of knee flexion. Beyond this angle, two of the nine combinations demonstrate poor knee flexion and were eliminated from the study.

RESULTS: The combination of circle cam with concave post, straight post and convex post showed 15.6, 15.9 and 16.1 mm posterior translation of the femur, respectively. The use of ellipse cam with convex post and straight post demonstrated a 15.3 and 14.9 mm femoral rollback, whilst the combination of triangle cam with convex post and straight post showed 16.1 and 15.8 mm femoral rollback, respectively.

CONCLUSION: The present study demonstrates that the use of circle cam and convex post created the best femoral rollback effect which in turn produces the highest amount of knee flexion. The findings of the study suggest that if the design is applied for knee implants, superior knee flexion may be possible for future patients.

METHODS: This single-blind, prospective, randomized, controlled trial involved intraoperative measurements for 271 femoral component implantations from 3 contemporary TKA systems, with 2 systems offering narrow sizing options. The difference between femoral component dimensions and the resected surface of distal femur was measured in millimeters at 5 distinct zones.

RESULTS: Overhang of standard femoral component was common in the anterior-medial condyle and anterior-lateral condyle ranging from 50.8% to 99.0% and 21.5% to 88.0%, respectively. With narrow femoral components, the rate of overhang reduced to 21.5%-30.2% and 9.2%-32.1%. Conversely, underhang rates were higher over the anterior flange width, middle medial-lateral and posterior medial-lateral zones. Standard components displayed higher underhang rates at these zones compared to narrow components. The good fit rate for femoral component was low among the 3 systems ranging from 1.0% to 56.0%. System with narrow option sizing increases the underhang rates in males, while improving the component fit among females at similar zones with rate ranging from 5.2% to 52.9%.

METHODS:  CT scans of 50 lower limbs were analyzed. Key anatomical landmarks such as the medial epicondyle (ME), lateral epicondyle, and transepicondylar width (TEW) were determined on 3D models constructed from the CT images. Best-fit planes placed on the most distal and posterior loci of points on the femoral condyles were used to define the distal and posterior joint lines, respectively. Statistical analysis was performed to determine the relationships between the anatomical landmarks and the distal and posterior joint lines.