A Prospective, Randomised Study Investigating the Use of a Fixed Loop Versus an Adjustable Suspensory Loop in Anterior Cruciate Ligament Reconstruction - a Comparison of Clinical and Functional Outcome

Study Aims and Objectives:

To investigate the following null hypothesis: that there is no difference in clinical and functional outcome when comparing outcomes of Anterior Cruciate Ligament (ACL) reconstruction when comparing femoral side graft fixation with either a fixed versus an adjustable suspensory loop system.

The research team will achieve this aim by:

• Enrolling 150 patients into this study over a period of 2 years and 8 months
• Carrying out a prospective randomised study looking at the subject matter over a period of 5 years and 8 months
• Analysing patients functional status pre and post-surgery using patient generated questionnaires
• Quantitatively measuring knee joint laxity using the KT1000 testing device at the 3, 6 and 12 month post-surgery time frames
• Collating the data received into a spread sheet for analysis by a professional statistician.

It is not uncommon to tear the anterior cruciate ligament (ACL) particularly during sporting activities. Younger and sportier patients will often have this ligament reconstructed so as to allow them to return to sport with a stable knee joint that they feel they can trust.

Various surgical techniques exist to perform ACL reconstruction. In Exeter, the favoured technique is to reconstruct the ligament by taking two of the hamstring tendons from the back of the knee and creating a graft with these, passing them through a bony tunnel to replace the torn ACL. On the shin bone side of the knee the graft is fixed in place using a screw. On the thigh bone side, the graft is attached to a device known as a suspensory loop.

The length of the graft and the length of the tunnel in the thigh bone vary from patient to patient. It is important to get a good length of the graft material in both the shin and thigh bones so as to give the best chance of the graft attaching to the surrounding bone. With the fixed loop system, once the metal button attached to the outer thigh bone is in place, the length of the loop cannot be adjusted. Thus the amount of hamstring graft in either end of the bony tunnel cannot be changed. One potential advantage of an adjustable loop system is that the amount of graft in either end of the bone tunnel can be altered to ensure sufficient graft is accurately placed.

The research team are planning to run this study to identify which type of loop system gives the best outcome for patients, examining the results in different ways including questionnaires to measure how well the patients feel their knee is performing, and specific tests to measure knee function.

If patients consent to be in the study, they will be randomly allocated to receive one of the 2 ACL reconstruction options above and their progress monitored for 2 years after the operation. All aspects of surgical care will be as routine practice apart from the decision to fix the graft to the thigh bone with an adjustable or fixed suspensory loop.