Single Hamstring ACL Reconstructions
Anterior Cruciate Ligament injuries are common among both elite sports people and the more sedentary population – both rupture their ACL’s for different reasons, and expectations and demands are quite varied. In general, an ACL reconstruction is necessary when you want to return to your normal sporting activities especially those involving pivoting, and side stepping. Those who play Football, Netball as well as Dancers, and people who require a lot of agility, in general would benefit from an ACL reconstruction. In the past, there were many types of ACL reconstruction methods, but over the decades, this has been refined to be a very predictable solution to a ruptured ACL. What method is best for you, should be selected by the expertise of your surgeon, as each surgeon has a method that they have refined over many years.
In the past, there were only a few choices for graft materials. These were typically Hamstring tendons (2 of) or Bone-Patellar Tendon – Bone. In recent times, other graft options have been trialed, such as quadriceps tendon and Peroneus Longus (in the ankle). Artificial graft options we’re also trialed, but are currently not as common due to the worse longer term outcomes. In general, it is best to use a graft that is biological (ie: a part of your living tissue). In other countries, there are options for grafts from a donor – this is called an Allograft, however in Australia, in general, these are not readily available.
Single Hamstring Technique
In recent years, the graft donor site morbidity (ie what happens to the area after you take the graft out) has been in review. In general, we want to cause the least amount of damage to an area after using a graft, so we don’t weaken areas once the graft is taken. Bone Patellar Bone has a history of causing long term anterior knee pain, especially when kneeling, so it is not our preferred option. It is a good backup option for complicated causes of revisions or when someone needs more graft material available in the case of a multiligamentous knee injury.
The single hamstring technique is one where only a single hamstring tendon is taken. Typically the Semi-Tendinosis tendon is taken, and folded in such a way that it yields a very uniformly thick graft, that is thicker than when 2 tendons were taken. In our experience, the graft size is thicker and closer to the normal size of a native ACL when the single hamstring technique is used. This is our preferred method, and one that we use on all of our elite athletes, and weekend warriors alike
The best rehabilitation after an ACL reconstruction is time. The new tendon needs to heal into the bone, and then slowly change its structure from a slightly elastic structure to a ligament – which has very little stretch capabilities. During this time (9-12 months), if the tendon is stretched, then the resulting tension on the graft will be too loose and the knee will end up feeling unstable. It is often difficult to withhold our patients from having accidents or from participating in the odd activity – which is why we utilise a reinforced technique, where a graft strengthener is placed within the ACL graft that acts to reduce the chance of stretching the ACL during its conversion from a tendon like structure to a ligament.
There is always a chance of rupturing the graft. Typically the highest risk is during the rehabilitation – especially if you return to your sports a bit too quickly, or twist hard on the knee during its recovery. The graft is actually the weakest at the 3 month post operative mark, which is often the time we’re introducing some more vigorous activities – it is very important to ensure that you are only doing straight line running and cycling at this time. Any agility activities need very close supervision to ensure that the graft does not stretch out or rupture. The reinforcement that we place can help to prevent inadvertent stretching of the graft during this time.
Method of tunnel drilling
Over the last 5 years, there has been a general movement towards drilling one of the tunnels through a small cut on the side of the knee, like a normal arthroscopy incision, rather than the traditional way of drilling through a hole in the tibial bone. The reason for this is that you can place the tunnel exactly where you need to, as it is not affected by where the hole in the tibia is placed. If you drill through the hole in the tibia, the hole in the femur is relatively set and the correct position may not be achieved.
What you can expect long term
The graft is extremely strong when it is placed within the knee, but the best rehabilitation is a combination of the instructions from your surgeon as well as participation with an ACL specialist physiotherapist. We utilise a handpicked cohort of physiotherapists to help guide you through your rehabilitation. The balance is there between strengthening the leg to prevent rupture and ensure a rapid return to sport, and to prevent stretching of the graft during its insertion.
How does Dr Liew perform ACL reconstructions?
- Single Hamstring using Graftlink technology
- Reinforcement placed within the graft.
- Drilling through the arthroscopy portal rather than through bone.
- Specialised buttons at the end of the graft, avoiding screws in the bone.
- Overnight stay in hospital
- Crutches for 1 week (Only as required)
- Weight bearing immediately after surgery
- Dedicated physiotherapy program.
- Return to high level, elite sport at 9 months to 1 year post op.