Posterior cruciate ligament (PCL) reconstruction: surgery and rehabilitation

Cambridge University Hospitals explains that the PCL is one of four major ligaments that stabilise the knee joint. The Mersey and West Lancashire leaflet says it tends to be the strongest ligament in the knee, running from the back of the shin bone to the front of the thigh bone, and that it stops the shin bone moving too far backwards behind the thigh bone.

A PCL injury is a partial or complete tear or stretch of the ligament. Cambridge says it typically occurs from a non-contact injury with the knee hyper-extended, often in sport, or from a direct blow to the shin while the knee is bent, as in a dashboard injury in a road traffic accident. The Mersey leaflet adds that it can follow landing awkwardly after a jump or falling hard on a bent knee.

The Mersey leaflet says a person may have swelling, pain and instability of the knee joint. If a PCL injury is suspected they may be assessed by a physiotherapist or orthopaedic consultant and referred for a scan to determine the severity of the injury and diagnose symptoms.

Cambridge notes that PCL injuries are often associated with injuries to other structures in the knee, such as the lateral collateral ligament, the ACL or the medial meniscus, though it can occur in isolation. A knee injury with a lot of swelling, a deformed knee, numbness or coldness in the foot, or inability to bear weight needs urgent assessment at A&E or a minor injuries unit.

Many isolated PCL injuries do not need an operation. The Mersey leaflet says some people function satisfactorily without a PCL by working on an intensive rehabilitation programme, and that if symptoms of knee instability persist, reconstruction is often necessary. Surgery is more likely when the PCL is torn together with other major ligaments, when the knee is unstable in daily activities, or when someone needs a high level of sport.

The leaflet lists the aims of surgery as improved knee stability, improved function and mobility, reduced pain and recovery of function and return to previous level of sport. For comparison, the NHS describes ACL surgery as something that may be needed if you play a lot of sport and want to continue, or if you keep having problems after trying physiotherapy.

The Mersey leaflet describes using part of the hamstring or gracilis tendons, taken from the inner side of the knee, to replace the torn PCL, with an artificial ligament used occasionally. A small incision is made over the upper inner shin to harvest the tendon, further small incisions allow an arthroscope into the knee, the remnant of the old PCL is cleared and tunnels are drilled in the shin and thigh bones so the graft can be passed through and secured at either end. If other knee trauma is present, a PCL reconstruction may be done at the same time as an ACL reconstruction or meniscus surgery.

Surgery is usually under general anaesthetic, sometimes with a nerve block for pain relief. The leaflet says most patients are discharged on the day of surgery or the day after.

The Mersey leaflet lists possible complications as pain, bleeding, wound infection, deep vein thrombosis, graft failure, failure to restore knee stability and failure to improve pain. It describes the signs of a DVT as localised pain in a muscle, sudden increase in swelling below the joint, increased temperature and redness, and advises seeking urgent medical advice if you suspect one.

The leaflet also stresses that pre-operative physiotherapy is extremely important: regaining full range of movement, strength and balance before surgery minimises problems afterwards.

Cambridge emphasises that rehabilitation is vital to ensure good functional outcomes, and that research links greater quadriceps strength to better knee function and return to activity. Its guide describes using elbow crutches for the first two weeks or longer, wearing a PCL brace for up to 24 weeks, aiming for 0 to 90 degrees of bending in the first 6 weeks and about 120 degrees by week 12, weaning off crutches when a good straight leg raise is achieved, and starting sport-specific training at around 24 weeks once strength and endurance allow.

The Mersey leaflet gives a more cautious protocol, with non-weight-bearing crutches and a straight-leg brace at first, then a JACK brace worn day and night for around 24 weeks. The two leaflets differ, so follow the instructions from your own surgeon and physiotherapist. You should only drive when your consultant agrees.

Cambridge says that return to sport should be based on meeting performance criteria rather than time alone. The earliest return is about six months, and the risk of re-injury is significantly reduced when return-to-sport criteria are met and by waiting until nine months. Psychological factors such as confidence and fear of re-injury are a normal part of recovery and differ from person to person.

If other structures such as the meniscus were repaired at the same time, the guide says the protocol may differ and progression is usually somewhat slower.

PCL reconstruction is performed by orthopaedic knee surgeons in NHS and private hospitals. It is a specialist operation, and it is reasonable to ask the surgeon how many PCL reconstructions they perform each year, what graft will be used and what the rehabilitation plan and follow-up will be.