The anterior cruciate ligament is an intra-articular ligament which stabilises the knee joint. It is often torn during physical activity and and this may occur after a rugby tackle or a sidestep. Associated injuries are meniscal tears and bone bruising around the articular surfaces. While not all anterior cruciate ligament tears require surgical management, there is a subset of patients that experience consistent instability episodes of the knee, which will require surgical ligament reconstruction. Other types of patients in whom surgery may be unavoidable are performance sportsmen who are unable to decrease their level of sports participation and are compelled to get back to full function rapidly, as well as patients with excessive ligament laxity. In our experience children have an immense ability to heal and we will only rarely recommend ligament reconstruction in this patient population unless they continue to suffer from severe instability despite optimal conservative treatment. Patients with multiple ligament injuries around the knee (usually after high velocity trauma such as motorcycle accidents) will also often require multiple ligaments to be reconstructed, including the ACL.
An MRI scan allows the clinician to determine associated injuries as well as the degree of ACL disruption. Commonly associated injuries are mainly meniscal tears which will often require repair. In these cases the MRI scan allows the surgeon to plan the procedure accurately. Associated posterior cruciate ligament or collateral ligament injury may also be confirmed with an MRI scan. Bone bruising is also diagnosed on MRI scan and allows the surgeon to provide the patient with an accurate prognosis. Knees with large areas of bone bruising adjacent to the joint surface tend to remain painful for longer, a longer and more arduous rehabilitations program is involved and the risk of post traumatic osteoarthritis is increased.
If a patient is assessed as requiring surgery, timing of the procedure is extremely important. While there is often a layman’s tendency to assume that early surgery is better, there exists extensive evidence in the scientific literature that inflamed, swollen knees with a significantly limited range of motion tend to become extremely stiff after early anterior cruciate ligament reconstruction. At the Cape Joint Surgery we look for a “benign” knee with a full range of motion and only minimal intra-articular swelling before surgical reconstruction is considered. As a rule 4 to 6 weeks of intensive physiotherapy and anti-inflammatory medication is required to get to this point.
Both surgeons at the Cape Joint Surgery have extensive experience with ACL reconstruction and these procedures are performed under a general anaesthetic through an arthroscopic (keyhole surgery) approach. As a rule, any associated injuries such as meniscal tears are treated first and in younger patients every attempt is made to perform a meniscal repair if at all possible. The anterior cruciate ligament can not be effectively repaired and therefore requires a graft reconstruction. While several options for graft material exists, we feel that the strength and versatility, as well as the complication profile of the four-strand hamstring graft makes it the ideal graft material for almost all patients, including basically all groups of performance sportsmen. Very rarely, patella tendon, allograft or synthetic graft material may be used (usually in a revision cases). The graft is harvested from the same leg through a 2 cm longitudinal incision just underneath the knee joint line. Once it has been prepared, the hamstring graft is introduced through pre-drilled tunnels in the tibia and femur, where it is secured with specialised fixation systems. As a rule, we use a femoral endo-button and a tibial interference screw.
Special care and attention is required to ensure that none of avoidable complications such as stiffening up of the knee are caused during the surgical procedure. Once the surgery is finished, an intensive physiotherapy rehabilitation program is instituted. Rapid rehabilitation post ACL reconstruction is possible and is becoming the rule in modern sports physiotherapy. Basically, the first aim of the physiotherapist is to ensure a full knee range of motion within the limitations set by the treating surgeon (if a meniscal repair is carried out, bracing with limited flexion is often required for the first few weeks). The next step is muscle strengthening (a disturbingly rapid degree of muscle wasting usually occurs in conjunction with an ACL tear). Once equivalent muscle strength can be demonstrated between the two legs, in-line acceleration/deceleration and running is allowed, followed by sports specific rehabilitation.
Much has been written about the necessity of an ACL reconstruction in patients which do not meet the previously discussed criteria. To date, no conclusive evidence exists that the lack of an ACL reconstruction results in early knee osteoarthritis. While patients with previous ACL tears may be at increased risk of developing subsequent meniscal tears, it is completely acceptable to deal with a deficient ACL at the time of meniscal debridement/repair.
