Validity and reliability of Thai version of the International Knee Documentation Committee Subjective Knee Form.

BACKGROUND: Self-administered questionnaires have become an important aspect for clinical outcome assessment of knee-related surgery. The International Knee Documentation Committee (IKDC) Subjective Knee Form is a knee-specific questionnaire that is widely used and translated to many languages. The purposes of the present study were: (1) to translate the questionnaire into Thai; and (2) to assess the validity and reliability of the Thai version of the International Knee Documentation Committee (IKDC) Subjective Knee Form. MATERIAL AND METHOD: The IKDC Subjective Knee Form was translated into Thai using forward-backward translation protocol. Afterward, reliability and validity were tested The responses of 55 consecutive patients on two questionnaires, the Thai IKDC Subjective Knee Form and the Short Form-36, were used. The validity was tested by correlating the scores from both questionnaires. The reliability was adopted by measuring the test-retest reliability and internal consistency. RESULTS: The Thai IKDC Subjective Knee Form showed good correlations with the physical functioning and bodily pain domains of the SF-36 (Pearson's correlation coefficient = 0.75 and 0.76 respectively). The reliability proved excellent with an intra-class correlation coefficient of 0.92 for test-retest. The internal consistency was strong (Cronbach alpha = 0.92). CONCLUSION: The Thai version of IKDC Subjective Knee Form showed good value to retain the characteristic of the original version. In addition, it was a reliable evaluation instrument for patients with knee-related problems.

Local compressive strength of the superolateral and sueromedial aspects of the anterior half of the talar dome: A biomechanical and histological study.

One cause of osteochondritis dissecans of the talar dome is related to trauma. The lesion occurs at the anterior half of the talar dome. The lateral osteochondritis dissecans is located at the superolateral aspect, while the medial lesion is located at the superomedial aspect. The lateral lesion is more common and its crater is shallower than that of the medial lesion. This study was therefore carried out to determine the local compressive strength of the superolateral and superomedial aspects of the anterior half of the talar dome. Ten pairs of fresh normal cadaveric tali were obtained. Using a universal testing machine, a compressive load was applied through a metal indenter at the superolateral and superomedial aspects of the talar dome until the maximal load was obtained. The maximal load and depth of depression were recorded. Histological studies of the compressive lesion was done using decalcified hematoxylin eosin stain. The results of the study showed that the superolateral aspect of the talar dome could withstand 1.27 times less compression load than could the superomedial aspect without a significant difference in stiffnesses. Moreover, the depth of depression of the superolateral compressive lesion was shallower than that of superomedial. Histological studies showed that the compressive lesion was a depression fracture. The depression fracture was a free osteochondral fragment surrounded by normal osteochondral tissue. The free fragment included articular cartilage, subchondral plate, and subchondral cancellous bone. The result of this study may explain why the prevalence of the lateral traumatic osteochondritis dissecans is higher, and its lesion crater shallower, than that of the medial aspect of the talar dome.

Failure mode of depressive osteochondral fracture under maximum compressive load: Studies of normal, osteoporotic, and osteosclerotic subchondral bones.

Objective: To determine the failure mode of depressive osteochondral fracture under the maximum compressive load. Design: An experimental cadaveric study. A compressive load was applied through an indenter on a femoral condyle to create a depressive osteochondral fracture until the maximum load was reached. Background: Most depressive osteochondral fractures occur without a gross articular cartilage injury because a large amount of load is reabsorbed by the surrounding tissues, especially the subchondral bone under the cartilage. We asked what the mode of depressive osteochondral fracture is. It might function as a load adsorber from the articular cartilage. Methods: Three groups of depressive osteochondral fractures were studied. Croup 1 consisted of 12 pieces of middle third of normal median and lateral femoral condyles. Groups 2 and 3 consisted of 12 pieces of osteoporotic and osteosclerotic middle of both femoral condyles. Using a universal testing machine, a depressive osteochondral fracture was created by applying a uniaxial compressive load through an indenter until the load rose to the maximum level. At that point, the load applied was stopped in order to minimize the extent of subchondral trabeculae fracture. Maximum load was recorded. Pressure and stiffness were calculated. The pattern of depressive fracture was studied histologically. Results: The failure mode of depressive osteochondral fracture wan such that the bone under the articular cartilage had a subchondral plate fracture, an interlacing of bone trabeculae under the plate, and a few fractures of the bone trabeculae. The interlacing of subchondral bone trabeculae was most evident in the normal bone as compared with the osteoporotic and osteosclerotic bones. The osteosclerotic bone failed at the highest load, while the osteoporotic bone failed at the lowest. Conclusion: The subchondral plate fracture and the interlacing of subchondral bone trabeculae under the plate are the characteristics of the failure mode of depressive ostechondral fracture. This failure mode occurs before there is a discernible fracture of the subchondral bone trabeculae. The amount of load causing fracture depends on the quality of the bone. Relevance: The failure mode, especially the interlacing of subchondral bone trabeculae, night function as a load absorber from the articular cartilage. Therefore, the quality of subchondral bone is important for protection of the articular cartilage from compressive load injury.

Local compressive strength at the middle of the weight-bearing surface of the femoral head and talar dome: A biomechanical study.

Objective: To compare the local compressive strength at the middle of the weight bearing surface of the femoral head and talar dome. Design: Cadaveric and comparative experimental study. The compressive strength of the talar dome and the femoral head were measured and compared. Background: The prevalence of late collapse of femoral head from avascular osteonecrosis is higher than that of the talar dome. The femoral head and acetabulum form a hip joint with monoarticulation whereas the talus itself has several articulations with several bones, so the talar dome distributes load more effectively from it the surroundings than does the femoral head. Compressive strength of the weight bearing surface of the femoral head and talar dome, however, may play a role in late collapse. Methods: Ten fresh cadaveric normal adult femoral heads and tali were obtained. A compressive load was applied through an indenter at the middle of the superior quadrant of the femoral head and talar dome by using a universal testing machine until a maximum load was obtained. The maximum load and depth of depression at maximum load were recorded. Results: The middle of the weight bearing surface of the femoral head could withstand an average maximum pressure of 30.42 MPa. Its stillness was 929.04 N/mm and its depth of depression was 1.11 mm. The corresponding figures for the talar dome were 49.64 Mpa, 1631.65 N/mm, and 0.96 mm respectively. Conclusion : This study showed that local compressive strength at the middle of the weight bearing surface of the talar dome was 1.63 times greater than that of the femoral head. Relevance : This finding may explain the higher prevalence of late collapsing avascular necrosis of the femoral head than that of the talar dome.