PCL rupture – whilst less common than ACL rupture – is even less commonly sufficiently symptomatic to warrant consideration of reconstruction, but if patients have instability, pain or swelling, reconstruction may be appropriate. This is predominantly performed with keyhole technique, requiring an overnight stay in hospital.
The posterior cruciate ligament (PCL) is a cord of tissue at the rear of the knee connecting the femur to the tibia which acts as a key stabiliser when performing movements going fowards in a straight line. When torn, it allows the knee to move abnormally, resulting in an unsteady knee which is prone to giving way especially if trying to slow down at the same time, such as when landing after jumping. PCL rupture may happen as a result of a blunt collisional trauma to the front of the tibia or by the weight of the body when jumping down whilst the knee is bent, or on occasion whilst the knee is out straight, hyperextending backwards.
The degree of pain and swelling with a PCL rupture is variable and usually will settle within three weeks. The likelihood of rupturing your PCL is about ten times less likely than that of injuring your ACL and in many cases, patients can manage to regain confidence with their knee without surgery, so the frequency of PCL reconstruction is much lower than ACL reconstruction. Those patients that have torn their PCL, who have undergone appropriate rehabilitation with an experienced physiotherapist and who still have symptomatic concerns such as giving way, swelling and pain may be candidates for a PCL reconstruction.
Reconstruction of the PCL is done using a predominantly keyhole procedure with four small incisions. Three of these incisions are made on the front of the knee, two of which are made in a horizontal orientation just below the knee cap and usually measuring less than 1cm each, with the third frontal incision being vertically oriented measuring 3cms or less and positioned three fingerbreadths below the knee cap.
The two horizontal incisions are used for the keyhole or arthroscopic visualisation and instrumentation of the knee and the vertical incision is used to harvest two small tendons from the medial thigh to reconstruct the PCL and to also drill the tibial bony tunnel for passage of the graft.
A fourth incision measuring 2cms is made on the inner or medial aspect of the knee towards the back of the knee to allow for a disposable arthroscopy portal to be positioned in the rear of the knee joint to allow for visualization and preparation of the tibial tunnel and graft passage at the very back of the knee whilst protecting the nerves and blood vessels.
Once the two tendons have been joined together and fashioned into a PCL like structure, it is firstly passed into the knee joint through the keyhole at the front before the lower end is pulled down the tibial drill hole.
Then the upper end is pulled into the femoral drill hole and is secured in both the femur and tibia with titanium screws. Two small drains are positioned within the knee to allow for drainage of any bleeding, a temporary extension splint is fitted and patients are admitted to the hospital for an overnight stay.
The day following surgery, the drains are removed and patients undergo an X-ray to confirm positioning of the femoral and tibial tunnels and screws.
Unlike an ACL reconstruction where crutches and a brace may only be needed for the first week or so, the effect of gravity and normal day to day activities affects the PCL more than the ACL and it needs to be protected with a specific PCL brace for the first three months and crutches are encouraged for at least the first month.
Patients commence a PCL specific exercise protocol with intermittent physiotherapy supervision to initially avoid excessive stretching of the PCL graft and wasting of their quadriceps and hamstring muscle bulk and then to help regain their strength and range of motion.
The rate of rehabilitation is usually one to two months slower than an ACL with patients usually being able to recommence leg weights and gym work by 4 to 5 months, unidirectional running by 5 to 6 months, multidirectional drills by 6 to 7 months, sports drills by 7 to 8 months and return to sporting competition by the end of their 8th or 9th month.
Most patients are able to return to work duties within a week or two if office based, slower if performing heavy manual duties.
Upon completion of your PCL rehabilitation, patients should be able to resume most sporting and outdoor activities with confidence.