Prehabilitation improves knee function following ACL reconstruction
Effect of prehabilitation on the outcome of anterior cruciate ligament reconstructionAm J Sports Med. 2013 Sep;41(9):2117-27
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Twenty-three patients, between the ages of 18 and 45, with an isolated ACL tear were randomly assigned into one of two groups to test the effect of a 6-week prehabilitation (exercise) program on functional outcomes. Patients received either a 6 weeks of prehabilitation before surgery or no prehabilitation at all. Results indicated that while quadriceps and hamstring peak torque were comparable between the groups following treatment, patients who received the prehabilitation program were more likely to experience an improvement in knee function (assessed through the single-legged hop test and Modified Cincinnati score) 12 weeks after surgery.
Was the allocation sequence adequately generated?
Was allocation adequately concealed?
Blinding Treatment Providers: Was knowledge of the allocated interventions adequately prevented?
Blinding Outcome Assessors: Was knowledge of the allocated interventions adequately prevented?
Blinding Patients: Was knowledge of the allocated interventions adequately prevented?
Was loss to follow-up (missing outcome data) infrequent?
Are reports of the study free of suggestion of selective outcome reporting?
Were outcomes objective, patient-important and assessed in a manner to limit bias (ie. duplicate assessors, Independent assessors)?
Was the sample size sufficiently large to assure a balance of prognosis and sufficiently large number of outcome events?
Was investigator expertise/experience with both treatment and control techniques likely the same (ie.were criteria for surgeon participation/expertise provided)?
Yes = 1
Uncertain = 0.5
Not Relevant = 0
No = 0
The Reporting Criteria Assessment evaluates the transparency with which authors report the methodological and trial characteristics of the trial within the publication. The assessment is divided into five categories which are presented below.
Inclusion / Exclusion
Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
The Fragility Index is a tool that aids in the interpretation of significant findings, providing a measure of strength for a result. The Fragility Index represents the number of consecutive events that need to be added to a dichotomous outcome to make the finding no longer significant. A small number represents a weaker finding and a large number represents a stronger finding.
Why was this study needed now?
Prehabilitation, defined as "the process of enhancing the functional capacity of an individual to enable them to withstand the stressor of inactivity", has been hypothesized as an effective way to improve the final outcomes of patients undergoing ACL reconstruction (ACLR). Preoperative quadriceps strength is an important factor in the functional outcome of the knee after ACLR, and enhancing the quadriceps strength and function before surgery (prehabilitation) may improve final outcomes. To date, no study has examined the effect of prehabilitation in combination with surgical reconstruction and aggressive postoperative rehabilitation on ACLR patients. This study was brought forward to address this question.
What was the principal research question?
What effect does prehabilitation have on the functional outcomes of ACLR patients when combined with surgical reconstruction and aggressive postoperative rehabilitation, 12 weeks after surgery completion?
What were the important findings?
- Single-legged hop test scores of the injured limb improved in both groups by final follow up (12 weeks), but the exercise group scored significantly higher (144.91 +/- 15.52) than the control (113.33 +/- 25.54) (p=0.001).
- Modified Cincinnati knee rating scores increased significantly from baseline (62.6) at the preoperative (76.5) and 12 week (85.3) time points for the exercise group (p=0.004 and 0.001, respectively). This finding was not shown by the control group. A significantly higher average Cincinnati knee rating score was found in the exercise group when compared to the control at the 12 week follow up (85.3 vs. 77.6, respectively) (p=0.004).
- No change in quadriceps CSA was found in the control group from baseline to preoperative follow up (p>0.05).
- Quadriceps peak torque increased significantly in the injured and uninjured limbs after the preoperative exercise program when compared to baseline (p=0.001 and 0.009 respectively). However, a significant decrease in quadriceps peak torque of the injured limb was found in the exercise group at the 12 week follow up (p=0.042, and P<0.001 when compared to baseline and preoperative measurements). No statistically significant differences were found between the exercise and control group for the injured limbs at any follow up regarding quadriceps peak torque (p>0.05).
- Compared with baseline, preoperative hamstring peak torque increased significantly in the injured limb in both groups (p=0.034 in the exercise group and p<0.001 in the control group). No differences were found between the groups at the pre or postoperative follow ups regarding this outcome (p>0.05).
- Compared to baseline measurements a significant increase in quadriceps CSA was found in the exercise group preoperatively (p=0.001). The difference between the two groups regarding this outcome, at the preoperative time point, was statistically significant in favour of the exercise group (p=0.0024). The improvements were not maintained in either group as the CSA decreased significantly at the 12 week follow up (p<0.001 for both groups). No difference in hamstring CSA was found between the groups at any point (p>0.05).
- The IGF-1 mRNA was significantly increased in the exercise group when compared to the control preoperatively (p=0.028). However, a significant decrease back to baseline levels in the exercise group was noted at the 12 week follow up (p=0.012). No differences were found between the two groups at any time point regarding: MuRF-1 mRNA, MAFbx mRNA, MHC I mRNA, and MHC IIx (p>0.05).
- The mean time to return to sport was 42.5 weeks for the control group compared to 34.18 weeks in the exercise group, this finding was not statistically different (p=0.055), but a trend towards quicker return to sport was noted in the exercise group.
What should I remember most?
The use of a 6 week prehabiliation intervention led to significantly improved knee function based on the results of the single-legged hop test and the modified Cincinnati score, which indicated a significantly higher average knee score when compared to controls. The prehabilitation intervention also lead to an increase in the IGF-1 gene following exercise intervention prior to surgery, but these levels decreased back to baseline levels at the 12 week follow up. Additionally, a trend towards quicker return to work was noted in the prehabilitation group.
How will this affect the care of my patients?
The results of this study indicate that a 6-week prehabilitation program for subjects undergoing ACL reconstruction (ACLR) has the potential to lead to improved knee function, and supports the notion that prehabilitation should be a consideration for patients awaiting ACLR. Further research must be completed with a larger sample size, and a longer follow up period.
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