Knee kinematics of severe medial knee osteoarthritis showed tibial posterior translation and external rotation: a cross-sectional study.

BACKGROUND: Knee osteoarthritis (OA) gradually reduces knee function and limits activities of daily living with age. However, the progression of abnormal kinematics of the knee in knee OA is unclear. AIMS: This study aimed to clarify the relationship between stage of knee OA and abnormal knee kinematics and to identify a strategy for prevention of knee OA. METHODS: A total of 112 knees of 99 patients (45 men/54 women; 55.9 ± 18.2 years), comprising 28 (27/1) in Kellgren-Lawrence grade 0, 18 (8/10) in grade 1, 27 (2/25) in grade 2, 28 (6/22) in grade 3, and 11 (3/8) in grade 4, were enrolled in this cross-sectional study. In vivo knee kinematics was obtained using a three-dimensional-to-two-dimensional registration technique utilizing CT-based bone models and lateral fluoroscopy during knee extension-flexion in an upright sitting position and squatting. RESULTS: The external rotation angle of the tibia relative to the femur was greater in grade 3/4 knees than in grade 0/1 knees and tibial posterior translation was greater in grade 3/4 knees than in grade 0-2 knees. DISCUSSION: Age-related changes in muscle activity and joint instability are considered to be the cause of these abnormal kinematics. CONCLUSIONS: As the stage of knee OA progresses, there was a tendency toward increasing tibial external rotation and tibial posterior translation during knee extension-flexion in sitting position and squatting. Prevention of the progress of the abnormal knee kinematics may prevent the progression of the knee OA.

In Vivo Kinematics of the Anterior Cruciate Ligament Deficient Knee During Wide-Based Squat Using a 2D/3D Registration Technique.

Anterior cruciate ligament (ACL) deficiency increases the risk of early osteoarthritis (OA). Studies of ACL deficient knee kinematics would be important to reveal the disease process and therefore to find mechanisms which would potentially slow OA progression. The purpose of this study was to determine if in vivo kinematics of the anterior cruciate ligament deficient (ACLD) knee during a wide-based squat activity differ from kinematics of the contralateral intact knee. Thirty-three patients with a unilateral ACLD knee consented to participate in this institutional review board approved study with the contralateral intact knee serving as the control. In vivo knee kinematics during the wide-based squat were analyzed using a 2D/3D registration technique utilizing CT-based bone models and lateral fluoroscopy. Comparisons were performed using values between 0 and 100° flexion both in flexion and extension phases of the squat activity. Both the ACLD and intact knees demonstrated increasing tibial internal rotation with knee flexion, and no difference was observed in tibial rotation between the groups. The tibia in the ACLD knee was more anterior than that of the contralateral knees at 0 and 5° flexion in both phases (p < 0.05). Tibiofemoral medial contact points of the ACLD knees were more posterior than that of the contralateral knees at 5, 10 and 15° of knee flexion in the extension phase of the squat activity (p < 0.05). Tibiofemoral lateral contact points of the ACLD knees were more posterior than that of the contralateral knees at 0° flexion in the both phases (p < 0.05). The kinematics of the ACLD and contralateral intact knees were similar during the wide-based squat except at the low flexion angles. Therefore, we conclude the wide-based squat may be recommended for the ACLD knee by avoiding terminal extension.

Association between stages of medial compartment osteoarthritis and three-dimensional knee alignment in the supine position: A cross-sectional study.

BACKGROUND: Osteoarthritis (OA) of the knee causes changes in knee alignment. A detailed knowledge of knee alignment is needed for correct assessment of the extent of disease progression, determination of treatment strategy, and confirmation of treatment effectiveness. However, deterioration of knee alignment during progression of OA has not been adequately characterized. The aims of this study were to clarify the changes in three-dimensional static knee alignment as knee OA stage progressed and to lay a foundation for an optimal treatment strategy to prevent knee malalignment. METHODS: A total of 106 knees of 81 patients ((men/women) 45/36; mean age 48.4 ±â€¯19.9 years; body mass index (BMI) 25.7 ±â€¯4.4 kg/m2) were enrolled in this cross-sectional study, comprising 34 (33/1) in Kellgren-Lawrence (KL) grade 0, 17 (8/9) in KL grade 1, 26 (5/21) in KL grade 2, 19 (4/15) in KL grade 3, and 10 (1/9) in KL grade 4. In all cases, computed tomography images were obtained with the subject in a reclined and relaxed position with the knee straight. Three-dimensional bone models were created from the images and knee alignment was calculated with six degrees-of-freedom. Then, 40 knees were selected consisting of 10 sex- and BMI-matched knees from each KL grade group: KL grade 1 (mean age 54.6 ±â€¯8.4 years; BMI 23.3 ±â€¯3.5 kg/m2), grade 2 (64.7 ±â€¯10.9 years; 27.3 ±â€¯3.2 kg/m2), grade 3 (69.2 ±â€¯11.4 years; 27.1 ±â€¯4.3 kg/m2), and grade 4 (71.9 ±â€¯9.2 years; 27.2 ±â€¯3.6 kg/m2). The Mann-Whitney U test with Bonferroni correction for multiple comparisons was used to analyze static alignment (α < 0.05/6). RESULTS: Alignment of the knee in flexion was -4.0 [95% confidence interval (CI): -6.4, -1.5] degrees, -3.4 [-8.0, 1.3] degrees, -0.1 [-3.7, 3.5] degrees, and 0.4 [-0.9, 1.6] degrees in the order of KL grade 1 to 4. There were significant differences between KL grade 1 and 4 (p = 0.0081). Anterior tibial translation was 6.6 [4.6, 8.6] mm, 5.8 [1.9, 9.7] mm, 1.0 [-2.5, 4.5] mm, and 1.3 [-2.4, 5.1] mm in the order of grade 1 to 4. There were significant differences between KL grade 1 and 4 (p = 0.0081). There were no significant differences in lateral tibial translation nor tibial rotation. CONCLUSIONS: The severely osteoarthritic knee joint was flexed and the tibia was displaced posteriorly with respect to the femur. Preventing these changes in alignment would assist in the prevention and treatment of knee OA.

Double-bundle anterior cruciate ligament reconstruction improves tibial rotational instability: analysis of squatting motion using a 2D/3D registration technique.

BACKGROUND: The anterior cruciate ligament-deficient (ACLD) knee requires appropriate treatment for the patient to return to sports. The purpose of this study was to clarify the kinematics of the anterior cruciate ligament-deficient knee in squatting motion before and after double-bundle anterior cruciate ligament reconstruction (DB-ACLR) using a 2D/3D registration technique. METHODS: The subjects of this study were 10 men with confirmed unilateral ACL rupture who underwent DB-ACLR. Computed tomography (CT) of the knee joints was performed before DB-ACLR. Fluoroscopic imaging of the knee motion in squatting before and after DB-ACLR was also performed. The 2D/3D registration technique is a method of calculating positional relationships by projecting the 3D bone model created from the CT data onto the image extracted from the fluoroscopic images. The tibial anteroposterior (AP) and rotational positions were analyzed with reference to the femur. RESULTS: The tibial AP position of the ACLD knees was significantly anterior to the contralateral knees (p = 0.015). The tibial rotational position of the ACLD knees was significantly internally rotated compared to the contralateral knees (p < 0.001). Both tibial AP and rotational positions improved after DB-ACLR (p < 0.001), with no significant differences compared to the contralateral knees. CONCLUSION: DB-ACLR improved not only tibial AP instability but also tibial rotational instability at knee flexion with weight-bearing. DB-ACLR appears to be a useful technique for normalizing the knee joint kinematics of ACLD knees.

In vivo kinematics of the talocrural and subtalar joints with functional ankle instability during weight-bearing ankle internal rotation: a pilot study.

Functional ankle instability (FAI) may involve abnormal kinematics. However, reliable quantitative data for kinematics of FAI have not been reported. The objective of this study was to determine if the abnormal kinematics exist in the talocrural and subtalar joints in patients with FAI. Five male subjects with unilateral FAI (a mean age of 33.4 ± 13.2 years) were enrolled. All subjects were examined with stress radiography and found to have no mechanical ankle instability (MAI). Lateral radiography at weight-bearing ankle internal rotation of 0° and 20° was taken with the ankle at 30° dorsiflexion and 30° plantar flexion. Patients underwent computed tomography scan at 1.0 mm slice pitch spanning distal one third of the lower leg and the distal end of the calcaneus. Three-dimensional (3D) kinematics of the talocrural and subtalar joints as well as the ankle joint complex (AJC) were determined using a 3D-to-2D registration technique using a 3D-to-2D registration technique with 3D bone models and plain radiography. FAI joints in ankle dorsiflexion demonstrated significantly greater subtalar internal rotation from 0° to 20° internal rotation. No statistical differences in plantar flexion were detected in talocrural, subtalar or ankle joint complex kinematics between the FAI and contralateral healthy joints. During ankle internal rotation in dorsiflexion, FAI joints demonstrated greater subtalar internal rotation. The FAI joints without mechanical instability presented abnormal kinematics. This suggests that abnormal kinematics of the FAI joints may contribute to chronic instability. FAI joints may involve unrecognized abnormal subtalar kinematics during internal rotation in ankle dorsiflexion which may contribute to chronic instability and frequent feelings of instability.