Date of Award

2012

Document type

Thesis

Degree Name

MD (Medical Doctor)

First Supervisor

Professor John O’Byrne

Second Supervisor

Professor Niall Moyna

Third Supervisor

Mr Ray Moran

Keywords

Anterior Cruciate Ligament Reconstruction, Rehabilitation

Abstract

Introduction: Anterior cruciate ligament injury results in quadriceps femoris atrophy. The effects of atrophy can persist after 5 years post anterior cruciate ligament reconstruction (ACLR) and can prolong rehabilitation [4]. Prehabilitation has been defined as preparing an individual to withstand a stressful event through enhancement of functional capacity before surgery [5]. We hypothesise that a preoperative exercise programme would enhance postoperative recovery.

Aims: To determine the effects of a 6-week lower limb strengthening and proprioceptive training programme prior to ACLR on lower limb strength and function, muscle cross-sectional area (CSA) and self-reported assessment at baseline, preoperative and 12-week postoperative period. To identify alterations in gene and protein expression involved in muscle hypertrophy and atrophy pathways at the same time points.

Methods: 22 volunteers awaiting ACLR were randomly assigned to a control or exercise intervention group. The exercise group completed a supervised 6-week gym and home based exercise programme. Postoperatively, all patients had a standard physiotherapy programme for 12 weeks. Assessments were completed at baseline, preoperatively and 12-week postoperatively..Assessments for primary outcomes include the single leg hop test and isokinetic dynamometry (N = ll for each group). Other assessments such as MRI quadriceps and hamstring CSA, in-line lunge test, Modified Cincinnati Knee Rating System and Tegner-Lysholm Knee Score were also measured (N = ll and 9 in exercise and control group respectively). A percutaneous muscle biopsy of the vastus lateralis muscle was performed at the same time points under either local or general anaesthetic (during ACLR). IGF-1, MuRF-1 and MAFbx mRNA expression was determined with qRT-PCR. Myosin Heavy Chain (MHC) isoform expression was determined with SDS-PAGE and qRT-PCR.

Results: Following 6 weeks of exercise intervention, the single leg hop test improved significantly in the exercise-injured limb compared to baseline and controls (p=0.001, p=0.046 respectively). Quadriceps strength in the injured limb had improved with similar gains in CSA compared to baseline (p=0.001). The vastus medialis CSA was also increased compared to controls (p=0.015). The Modified Cincinnati Knee Rating System was also better compared to baseline.

At 12-week postoperatively, the decline in the single hop test was reduced in the exercise group compared to controls (p=0.001). Similar trends were seen for the quadriceps strength and CSA but were not statistically significant. The vastus medialis CSA had regressed to similar levels as the control group (p=0.008). The Modified Cincinnati Knee Rating System score continued to increase in the exercise group compared to controls (p=0.004).

The expression of IGF-1 gene was significantly increased after the exercise intervention (p=0.028), decreasing back to baseline 12-week postoperatively (p=0.012). MuRF-1 gene expression was decreased after intervention compared to baseline (p=0.05) but increased at 12-week postoperatively (p=0.Q3). MAFbx levels did not change significantly in either group and within each time point. On mRNA level, there was a shift from MHC-llx isoform to MHC-lla after exercise, with significant changes compared to controls preoperatively (p=0.03). Protein testing was only able to reproduce this increment for MHC-llx isoform expression only.

Conclusion: 6-week progressive prehabilitation programme for subjects undergoing ACLR is safe and led to improved knee function, quadriceps strength and CSA, and self-reported assessment pre- and postoperatively. This study supports prehabilitation as an important consideration for patients awaiting ACLR.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

File Size

9.12 MB

Comments

A thesis submitted to the Royal College of Surgeons in Ireland for the degree of Doctor of Medicine from the National University of Ireland in 2012.

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