Limits...
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.

Show MeSH

Related in: MedlinePlus

Study design with internal fixation and spontaneous recovery durations and sample size per group. Angle of extension in rat knee joints for the 24 groups at torque = 12.5 N-cm. *P ≤ 0.05 for difference between the mean ranges of knee extension of contracture versus contralateral knees. All P > .001 identified. #P ≤ 0.05 for gain in knee extension angle after recovery duration half, equal to, double, or quadruple the duration of surgical fixation compared to the previous duration. Error bars = 1 standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: Study design with internal fixation and spontaneous recovery durations and sample size per group. Angle of extension in rat knee joints for the 24 groups at torque = 12.5 N-cm. *P ≤ 0.05 for difference between the mean ranges of knee extension of contracture versus contralateral knees. All P > .001 identified. #P ≤ 0.05 for gain in knee extension angle after recovery duration half, equal to, double, or quadruple the duration of surgical fixation compared to the previous duration. Error bars = 1 standard error of the mean.

Mentions: This project was approved by the University of Ottawa Animal Care Committee. Rat knee contractures of various severities were produced by extra-articular fixation of one knee of 250 adult male Sprague–Dawley rats, each weighing 325 g, aiming for a final sample size of 40 each for six durations: 1, 2, 4, 8, 16 or 32 weeks [7]. Briefly, under general anesthesia and alternating right and left legs, a Delrin® plate was surgically fixed with screws to the proximal femur and distal tibia. This surgical internal fixation spanned the knee joint, away from all intra-articular knee structures while achieving rigid fixation in 45° of flexion [7]. Preoperatively the rats received slow-release buprenorphine and ketamine. Bupivacaine hydrochloride was applied transdermally at closure. Rats had access to food ad libitum and their activity was unrestricted in cages. Leg pain beyond 4 days post-op was treated with gabapentin s/c for 7 days. Nonsteroidal anti-inflammatory medications were avoided. Wound infections were treated with amoxicillin trihydrate/clavulanate potassium orally twice daily for 7 days; fluoroquinolones were avoided. More animals were operated in experimental groups of greater severity in anticipation of attrition. Animals with surgical failures or requiring euthanasia ahead of endpoint were replaced.At the end of the fixation period, the plate and screws were removed; also, any fibrous tissue covering the plate was divided at the proximal femur and distal tibia. The procedure created knee flexion contractures of various levels of severity depending on the duration of fixation. The rats were assigned to 1 of 4 durations of spontaneous recovery (approximately 10 per duration; Figure 1). One group was killed immediately after plate removal and represented the contracture with no recovery. All groups had one duration of recovery equal to that of fixation (Figure 1). For the first 5 durations of fixation (1, 2, 4, 8 and 16 weeks) one group had a duration of recovery double the duration of fixation (Figure 1). Finally, for the first 4 durations of fixation (1, 2, 4 and 8 weeks), one group had a duration of recovery four times that of the duration of fixation (Figure 1). We could not double the duration of recovery of knees surgically fixed for 32 weeks or quadruple the duration of recovery in animals fixed for 16 and 32 weeks owing to the 2-year life expectancy of the Sprague–Dawley rat. Therefore, for these 2 durations, spontaneous recovery period equal to half the duration of fixation was studied (Figure 1).Figure 1


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)

Study design with internal fixation and spontaneous recovery durations and sample size per group. Angle of extension in rat knee joints for the 24 groups at torque = 12.5 N-cm. *P ≤ 0.05 for difference between the mean ranges of knee extension of contracture versus contralateral knees. All P > .001 identified. #P ≤ 0.05 for gain in knee extension angle after recovery duration half, equal to, double, or quadruple the duration of surgical fixation compared to the previous duration. Error bars = 1 standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: Study design with internal fixation and spontaneous recovery durations and sample size per group. Angle of extension in rat knee joints for the 24 groups at torque = 12.5 N-cm. *P ≤ 0.05 for difference between the mean ranges of knee extension of contracture versus contralateral knees. All P > .001 identified. #P ≤ 0.05 for gain in knee extension angle after recovery duration half, equal to, double, or quadruple the duration of surgical fixation compared to the previous duration. Error bars = 1 standard error of the mean.
Mentions: This project was approved by the University of Ottawa Animal Care Committee. Rat knee contractures of various severities were produced by extra-articular fixation of one knee of 250 adult male Sprague–Dawley rats, each weighing 325 g, aiming for a final sample size of 40 each for six durations: 1, 2, 4, 8, 16 or 32 weeks [7]. Briefly, under general anesthesia and alternating right and left legs, a Delrin® plate was surgically fixed with screws to the proximal femur and distal tibia. This surgical internal fixation spanned the knee joint, away from all intra-articular knee structures while achieving rigid fixation in 45° of flexion [7]. Preoperatively the rats received slow-release buprenorphine and ketamine. Bupivacaine hydrochloride was applied transdermally at closure. Rats had access to food ad libitum and their activity was unrestricted in cages. Leg pain beyond 4 days post-op was treated with gabapentin s/c for 7 days. Nonsteroidal anti-inflammatory medications were avoided. Wound infections were treated with amoxicillin trihydrate/clavulanate potassium orally twice daily for 7 days; fluoroquinolones were avoided. More animals were operated in experimental groups of greater severity in anticipation of attrition. Animals with surgical failures or requiring euthanasia ahead of endpoint were replaced.At the end of the fixation period, the plate and screws were removed; also, any fibrous tissue covering the plate was divided at the proximal femur and distal tibia. The procedure created knee flexion contractures of various levels of severity depending on the duration of fixation. The rats were assigned to 1 of 4 durations of spontaneous recovery (approximately 10 per duration; Figure 1). One group was killed immediately after plate removal and represented the contracture with no recovery. All groups had one duration of recovery equal to that of fixation (Figure 1). For the first 5 durations of fixation (1, 2, 4, 8 and 16 weeks) one group had a duration of recovery double the duration of fixation (Figure 1). Finally, for the first 4 durations of fixation (1, 2, 4 and 8 weeks), one group had a duration of recovery four times that of the duration of fixation (Figure 1). We could not double the duration of recovery of knees surgically fixed for 32 weeks or quadruple the duration of recovery in animals fixed for 16 and 32 weeks owing to the 2-year life expectancy of the Sprague–Dawley rat. Therefore, for these 2 durations, spontaneous recovery period equal to half the duration of fixation was studied (Figure 1).Figure 1

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