On “Effectiveness of stretch for the treatment and prevention of contractures…” Katalinic OM, Harvey LA, Herbert RD. Phys Ther. 2011;91:11–24.

I am writing in regard to Katalinic and colleagues' responses¹ to my comments² on their article “Effectiveness of Stretch for the Treatment and Prevention of Contractures in People With Neurological Conditions: A Systematic Review.”³

Katalinic et al stated that “only 4 of the 25 studies demonstrated a statistically significant between-group difference,^4–7 and, in 3 of these studies, this effect was evident only within the first 24 hours upon removal of stretch. The immediate effects of stretch probably are due to viscous deformation and not intrinsically useful for the treatment and prevention of contractures….” The results of these 3 studies should not be attributed to viscous deformation only. Although there is value in performing the measurements 24 hours after the last treatment,⁵ it would not be necessary to wait an entire 24 hours to completely eradicate the transient effects of the stretch interventions. Two of the 3 studies^4,6 mentioned that measurements were not made immediately after the interventions specifically for this reason. In the third study,⁷ it appears that some effects of the casting and stretching intervention lasted for at least 1 week after the intervention ceased.

Furthermore, I do not agree that viscous deformation is not useful for contracture management. Viscous deformation has been studied using various types of intermittent stretching (with stretch application lasting from 15 seconds to 20–30 minutes).^8–11 The results of these studies suggest that the magnitude and duration of viscous deformation varies depending on method of stretch application and on the rate, frequency, and duration of force applied.^8–11 It is well established that constant stretch application of prolonged duration lasting days,¹² weeks,¹³ and months¹⁴ (as in casting in elongated positions¹³ and serial casting or limb-lengthening procedures^12,14) can induce changes on a cellular level that result in lasting length increases. In 2 studies, the stretch intervention lasted for a number of hours each day over a period of 1 week⁷ or 2 weeks.⁶ It is not clear what stretching stimulus is required for the transient effects of viscoelastic deformation to develop into more lasting length increases. Even if we assume that these results were due entirely to viscoelastic deformation, the findings would still be clinically relevant and suggest the need for further research regarding how to prolong and enhance the increases in muscle extensibility.

Katalinic et al said that “there is no suggestion from the results that the ‘direct application of stretch’ (or any other application of stretch) was effective for prevention of contracture. The trial by Horsley et al^[15] did not demonstrate a statistically significant between-group difference for range of motion. The trial by Ben et al⁵ did show a statistically significant between-group difference, but, as articulated by the authors, the size of the between-group difference was trivially small.” I contend that these 2 studies demonstrate why it is important to understand the intent of the study and assess the initial severity of contractures when evaluating study results. In both studies, neither test group demonstrated contractures initially, so the intent of the interventions must have been contracture prevention. The patient populations apparently were chosen because they were considered at high risk for contracture development. In both studies, the authors concluded that no significant contractures developed in the stretch intervention groups. How could there be a better treatment outcome? The goal of contracture prevention was achieved. The between-group treatment effect is a secondary issue because its magnitude is largely dependent upon whether contractures developed in the control group. Details of study methods should be considered carefully when evaluating the significance of between-group treatment effects, because the magnitude of contracture development in the control group can be influenced by a number of factors that are immaterial to the effectiveness of the stretching intervention.

According to Katalinic et al, “[no trials] demonstrated a superior effect from splinting and casting when administered in combination with passive stretching…. Unbiased estimates of effects of interventions can only be obtained from between-group differences.” I agree that none of these studies tested the effectiveness of a splinting or casting intervention alone compared with splinting or casting combined with a direct stretching intervention. But outcomes of the studies involving splinting or casting that included direct stretching^7,16 were better than the outcomes of the studies that used splinting or casting, and the participants were specifically instructed to refrain from additional stretching^17–19 or the splinting or casting intervention was not performed concurrently with the direct stretch intervention.⁶

For example, 2 studies by Lannin et al^16,17 assessed the effect of wrist splints on wrist and finger muscle extensibility in individuals with hemiplegia. In their 2003 study, there was no between-group treatment effect because neither the control group nor the treatment group developed contractures. In their 2007 study, there was no between-group treatment effect because both groups developed similar contractures of 17 degrees. The study in which none of the participants developed contractures¹⁶ included regular stretching in the treatment regimen. In the study in which there was significant contracture formation,¹⁷ passive stretching was specifically excluded from the treatment program, and wrist and finger extension exercises were limited.

These studies do not provide conclusive evidence, and this is not a large number of studies. Overall, however, the results suggest a general trend toward greater effectiveness in contracture management when splinting or casting is combined with a regular stretching program. Perhaps future research involving casting or splinting should consider including a direct stretch intervention.

Katalinic and colleagues questioned the efficacy of stretch-based interventions for contracture management. Yet they also acknowledged that “in all studies, participants in both groups continued to receive usual care,”^3(p22) which may have included routine application of stretch in daily care and rehabilitation. Their review, therefore, assessed only the additive effect of specific stretch interventions rather than the efficacy of comprehensive contracture management programs.

The application of stretch in various forms is an integral part of contracture management and has sound support in basic science and clinical experience, so completely withholding all forms of stretch from patients who have contractures or who are at high risk of developing contractures is difficult and borders on being unethical. Therefore, it is difficult to fully assess the effects of a comprehensive contracture management program (or stretch application in general).

Katalinic and colleagues concluded that “stretch-based interventions administered for less than 6 months are ineffective for treating and preventing contracture in neurological populations.”¹ Yet they also concluded that “stretch” interventions are ineffective (for contracture management) immediately and in the short term and long term.³ Do they recommend that therapists continue to administer ineffective treatments for a longer period of time (ie, greater than 6 months) in hopes that they become effective at some point?

As I see it, stretching interventions can be effective immediately and in the short term; however, some form of stretch may need to be continued on a regular basis for successful long-term contracture management. Contractures often are associated with chronic clinical conditions, so some stretch interventions may need to be continued for longer than just a few weeks in order to maintain motion increases and prevent contracture formation. This may be especially true in patients with neurological disorders when the underlying disorder creates a predisposition toward contracture development. In these patients, adjunct medical treatments that address the underlying cause of contracture formation (eg, anti-spasticity medicine, botulinum toxin injections, gene therapy) may be required.

Many studies included in the systematic review did not consider this type of clinical reasoning in their design, so the overall contracture management programs are not as comprehensive as those found in clinical practice. Therefore, study results may not accurately reflect clinical outcomes.

Herbert, Harvey, and colleagues have produced some of the most relevant clinical research regarding contractures and the biomechanical effects of stretching because they are among the first to recognize the importance of measuring muscle extensibility using standardized torques. Our disagreement lies in the interpretation of the results of the studies in their systematic review.

• © 2012 American Physical Therapy Association