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Quantitative analysis of the reversibility of knee flexion contractures with time: an experimental study using the rat model.

Trudel G, Uhthoff HK, Goudreau L, Laneuville O - BMC Musculoskelet Disord (2014)

Bottom Line: The etiology is not well defined.Extended periods of immobilization of joints lead to contractures difficult to completely reverse by rehabilitation treatments.No reversal occurred in the highest severity group (32 week; P>0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Rd,, Ottawa, ON K1H 8M5, Canada. gtrudel@ottawahospital.on.ca.

ABSTRACT

Background: Knee flexion contractures prevent the full extension of the knee joint and cause disability. The etiology is not well defined. Extended periods of immobilization of joints lead to contractures difficult to completely reverse by rehabilitation treatments. Recovery of the complete range of motion without intervention has not been studied but is of importance to optimize clinical management. This study was designed to quantify the spontaneous reversibility of knee flexion contractures over time.

Methods: Knee flexion contractures of increasing severities were induced by internally fixing one knee of 250 adult male rats for 6 increasing durations. The contractures were followed for four different durations of spontaneous recovery up to 48 weeks (24 groups, target n=10 per group). The angle of knee of extension at a standardized torque was measured. Contralateral knees constituted controls.

Results: Full reversibility characterized by knee extension similar to controls was only measured in the lowest severity group where 4 weeks of spontaneous recovery reversed early-onset contractures. Spontaneous recovery of 2, 4 and 8 weeks caused partial gain of knee extension in longer-lasting contractures (P ≤ 0.05; all 4 comparisons). Extending the durations of spontaneous recovery failed to further improve knee extension (P>0.05, all 12 comparisons). No reversal occurred in the highest severity group (32 week; P>0.05).

Conclusions: Reversibility of knee flexion contractures was dependent on their severity. Full spontaneous recovery was limited to the least severe contractures. While contractures initially improved, a plateau was reached beyond which additional durations of spontaneous recovery led to no additional gain of knee extension. These results support our view that without treatment, permanent losses in knee mobility must be anticipated in immobility-induced contractures.

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Arthrometer used to measure angle of extension. The right femur is fixed in a grooved metal clamp (F). The lateral condyle is positioned at the center of rotation (C). A motor-driven movable arm with two uprights posts pushes the posterior leg (L) into extension at a fixed distance from the center of rotation and at a predetermined speed. At torque = 12.5 N-cm a picture is taken of the knee (left upper corner insert shows the camera mounted above the arthrometer). The femorotibial angle is drawn using the femoral line from lateral condyle (C) to the middle of the femur clamp (F) (femoral diaphysis) and the tibial line from the lateral condyle (C) to lateral malleolus (M). The femorotibial angle corresponds to the angle of extension reached by the knee, with full extension defined at 180°. Once the rat leg is positioned, joint angle measurement is investigator-independent.
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Fig2: Arthrometer used to measure angle of extension. The right femur is fixed in a grooved metal clamp (F). The lateral condyle is positioned at the center of rotation (C). A motor-driven movable arm with two uprights posts pushes the posterior leg (L) into extension at a fixed distance from the center of rotation and at a predetermined speed. At torque = 12.5 N-cm a picture is taken of the knee (left upper corner insert shows the camera mounted above the arthrometer). The femorotibial angle is drawn using the femoral line from lateral condyle (C) to the middle of the femur clamp (F) (femoral diaphysis) and the tibial line from the lateral condyle (C) to lateral malleolus (M). The femorotibial angle corresponds to the angle of extension reached by the knee, with full extension defined at 180°. Once the rat leg is positioned, joint angle measurement is investigator-independent.

Mentions: The knee contractures were not complicated by factors such as intra-articular trauma or change in neurological status. The joints received no physical intervention after fixation removal: the data correspond to spontaneous or untreated recovery of knee contracture.At endpoint, the rats were killed by administration of carbon dioxide. The knee angle of extension was measured using a motor-driven arthrometer (Figure 2). The animal was positioned on its side with the experimental leg facing upwards. The femur was secured in a grooved metal clamp. The lateral condyle was adjusted over the center of rotation of the arthrometer. A movable arm with two upright posts positioned behind the leg pushed it into extension with a force of 426 g applied at a distance of 30 mm of the center of rotation. The initial speed of rotation of 6.6 RPM was gradually slowed down until a torque of 12.5 N-cm was reached. This torque was selected because it achieves complete knee extension in normal rats. The motor then stopped while a camera (Canon EOS-500D, 30–2, Shimomaruko 3-chome, Ohta-ku, Tokyo 146–8501, Japan) attached to the frame of the arthrometer was triggered to take a picture (Figure 2). The rigid fixation of the arthrometer and the force applied horizontally optimized the acquisition of true lateral images without distortion. The animal was then turned onto its other side, and the same measures were repeated on the contralateral knee. The knee joint angle measurement was fully automated and operator-independent. In this study, full knee extension was defined as 180°.Knee images were analyzed by the same person, blinded to the experimental set-up of the animal. Images were opened with ImageJ version 1.45 s (National Institutes of Health, Bethesda, Maryland) and calibrated. The two arms of the femorotibial angle were drawn using the angle tool. The femoral line was drawn from the lateral condyle to the middle of the femur clamp (aligned with the femoral diaphysis) (Figure 2). The tibial line went from the lateral femoral condyle to the lateral malleolus (Figure 2). The femoro-tibial angle corresponded to the maximal angle of knee extension reached at the preset torque.Figure 2


Quantitative analysis of the reversibility of knee flexion contractures with time: an experimental study using the rat model.

Trudel G, Uhthoff HK, Goudreau L, Laneuville O - BMC Musculoskelet Disord (2014)

Arthrometer used to measure angle of extension. The right femur is fixed in a grooved metal clamp (F). The lateral condyle is positioned at the center of rotation (C). A motor-driven movable arm with two uprights posts pushes the posterior leg (L) into extension at a fixed distance from the center of rotation and at a predetermined speed. At torque = 12.5 N-cm a picture is taken of the knee (left upper corner insert shows the camera mounted above the arthrometer). The femorotibial angle is drawn using the femoral line from lateral condyle (C) to the middle of the femur clamp (F) (femoral diaphysis) and the tibial line from the lateral condyle (C) to lateral malleolus (M). The femorotibial angle corresponds to the angle of extension reached by the knee, with full extension defined at 180°. Once the rat leg is positioned, joint angle measurement is investigator-independent.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4289348&req=5

Fig2: Arthrometer used to measure angle of extension. The right femur is fixed in a grooved metal clamp (F). The lateral condyle is positioned at the center of rotation (C). A motor-driven movable arm with two uprights posts pushes the posterior leg (L) into extension at a fixed distance from the center of rotation and at a predetermined speed. At torque = 12.5 N-cm a picture is taken of the knee (left upper corner insert shows the camera mounted above the arthrometer). The femorotibial angle is drawn using the femoral line from lateral condyle (C) to the middle of the femur clamp (F) (femoral diaphysis) and the tibial line from the lateral condyle (C) to lateral malleolus (M). The femorotibial angle corresponds to the angle of extension reached by the knee, with full extension defined at 180°. Once the rat leg is positioned, joint angle measurement is investigator-independent.
Mentions: The knee contractures were not complicated by factors such as intra-articular trauma or change in neurological status. The joints received no physical intervention after fixation removal: the data correspond to spontaneous or untreated recovery of knee contracture.At endpoint, the rats were killed by administration of carbon dioxide. The knee angle of extension was measured using a motor-driven arthrometer (Figure 2). The animal was positioned on its side with the experimental leg facing upwards. The femur was secured in a grooved metal clamp. The lateral condyle was adjusted over the center of rotation of the arthrometer. A movable arm with two upright posts positioned behind the leg pushed it into extension with a force of 426 g applied at a distance of 30 mm of the center of rotation. The initial speed of rotation of 6.6 RPM was gradually slowed down until a torque of 12.5 N-cm was reached. This torque was selected because it achieves complete knee extension in normal rats. The motor then stopped while a camera (Canon EOS-500D, 30–2, Shimomaruko 3-chome, Ohta-ku, Tokyo 146–8501, Japan) attached to the frame of the arthrometer was triggered to take a picture (Figure 2). The rigid fixation of the arthrometer and the force applied horizontally optimized the acquisition of true lateral images without distortion. The animal was then turned onto its other side, and the same measures were repeated on the contralateral knee. The knee joint angle measurement was fully automated and operator-independent. In this study, full knee extension was defined as 180°.Knee images were analyzed by the same person, blinded to the experimental set-up of the animal. Images were opened with ImageJ version 1.45 s (National Institutes of Health, Bethesda, Maryland) and calibrated. The two arms of the femorotibial angle were drawn using the angle tool. The femoral line was drawn from the lateral condyle to the middle of the femur clamp (aligned with the femoral diaphysis) (Figure 2). The tibial line went from the lateral femoral condyle to the lateral malleolus (Figure 2). The femoro-tibial angle corresponded to the maximal angle of knee extension reached at the preset torque.Figure 2

Bottom Line: The etiology is not well defined.Extended periods of immobilization of joints lead to contractures difficult to completely reverse by rehabilitation treatments.No reversal occurred in the highest severity group (32 week; P>0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Rd,, Ottawa, ON K1H 8M5, Canada. gtrudel@ottawahospital.on.ca.

ABSTRACT

Background: Knee flexion contractures prevent the full extension of the knee joint and cause disability. The etiology is not well defined. Extended periods of immobilization of joints lead to contractures difficult to completely reverse by rehabilitation treatments. Recovery of the complete range of motion without intervention has not been studied but is of importance to optimize clinical management. This study was designed to quantify the spontaneous reversibility of knee flexion contractures over time.

Methods: Knee flexion contractures of increasing severities were induced by internally fixing one knee of 250 adult male rats for 6 increasing durations. The contractures were followed for four different durations of spontaneous recovery up to 48 weeks (24 groups, target n=10 per group). The angle of knee of extension at a standardized torque was measured. Contralateral knees constituted controls.

Results: Full reversibility characterized by knee extension similar to controls was only measured in the lowest severity group where 4 weeks of spontaneous recovery reversed early-onset contractures. Spontaneous recovery of 2, 4 and 8 weeks caused partial gain of knee extension in longer-lasting contractures (P ≤ 0.05; all 4 comparisons). Extending the durations of spontaneous recovery failed to further improve knee extension (P>0.05, all 12 comparisons). No reversal occurred in the highest severity group (32 week; P>0.05).

Conclusions: Reversibility of knee flexion contractures was dependent on their severity. Full spontaneous recovery was limited to the least severe contractures. While contractures initially improved, a plateau was reached beyond which additional durations of spontaneous recovery led to no additional gain of knee extension. These results support our view that without treatment, permanent losses in knee mobility must be anticipated in immobility-induced contractures.

Show MeSH
Related in: MedlinePlus