A multiligament injury to the knee is when 3 or more ligaments have been partly or completely torn. It is uncommon to sustain a multiligament injury to the knee but should this occur, if it is not managed correctly with consideration of staged or simultaneous reconstruction of one or several ligaments, then knee function may suffer significantly.
It is uncommon to sustain 3 or more ligament injuries to the knee and should this occur, the knee function is likely to suffer significantly. A multiligament injury usually requires a high energy injury, such as a motorbike or car accident, and on occasion a deceleration sporting injury such as snow skiing or waterskiing to sustain this degree of trauma to the knee. Initial assessment and management of the knee with multiple ligament injuries is imperative, and the patient may have sustained other limb and life threatening injuries which are prioritised and managed accordingly. The knee may have been placed in a splint or had an external fixation device fitted to the knee with a series of pins passing into the femur and tibia with rods or rings attached to the pins to help hold the knee stable in a fixed manner to protect the surrounding nerves, blood vessels and other structures in the knee.
It is of critical importance to ensure that the knee is returned to a normal or near normal position and safely held in that position, as soon as possible, to avoid serious complications such as damage to the blood vessels behind the knee or death of the muscle in the calf or necrosis of the overlying skin and soft tissue, which can occur in a “dislocated knee”. Once the knee is in a more normal or non-dislocated (reduced) position, the pulses in the feet need to be reassessed and monitored regularly and simple plain X-rays are needed to confirm the positioning of the knee, and if necessary additional imaging for the blood vessels (arteriogram) may be needed.
More detailed assessment of the injured ligaments can usually be made clinically by examining the stability of the knee and reviewing the X-rays, and when the urgency of the acute injury has passed, a Magnetic Resonance Imaging (MRI) study of the knee, should be performed to demonstrate not only the ligaments of the knee but also the meniscal and articular cartilage, which is often damaged as well. Specific sequences in each of three different planes (coronal, sagittal, axial) should be performed to obtain the optimal amount of information.
Reconstruction of three or more ligaments, equates to a multiligament reconstruction, which includes any number of combinations of the ligament reconstructions described elsewhere (see ACL, PCL, LCL, MCL, PLC). The timing for surgery is influenced by many variables including stabilisation of other limb and life threatening conditions if they exist, and to proceed when the soft tissue surrounding the knee is minimally swollen and clean and dry, with no cuts scratches abrasions or infection, including at pin sites from the external fixation devices if present. Timing from the initial injury also influences whether some of the damaged structures are repaired or reattached rather than reconstructed, and ideally surgery should be performed within the first 24 hours before swelling becomes established or delayed 1 to 2 weeks to allow swelling to resolve before commencing surgery to minimise the risk of wound complications.
Other important considerations include prevention of blood clots or deep vein thrombosis, using sequential compression stockings, encouraging foot movement and other calf compression exercises and devices, chemical anticoagulants (Heparin, Aspirin, Warfarin, Xarelto, Apixaban) and by keeping the leg elevated and where possible both the limb and the patient as mobile as possible, usually with the assistance of a physiotherapist. Surgical reconstruction of multiple ligaments can be done all at once or in a staged manner and is influenced by the degree of swelling in the knee, the number and type of ligaments involved, and the graft choice decided upon.
Priority is usually afforded to the posterolateral corner (PLC) and if both collateral ligaments (MCL, LCL) and both cruciates (ACL, PCL) are also ruptured, to reconstruct/repair at least one collateral and one cruciate ligament at the same time as the PLC to allow for the knee to commence early movement, with a hinged range of motion splint and to reassess stability of the other ligaments in a delayed manner once the knee has regained range of motion, some strength and swelling control. Quite often a period of splinting and range of motion after initial surgery will decrease the number of remaining injured ligaments requiring further surgery, and this may overcome the inevitable shortage of the patients own (autogenous) donor tissue available to reconstruct the multiply injured knee.
If the number of ligaments requiring reconstruction cannot be adequately dealt with by harvesting tissue from the same knee, other graft choices include consideration of harvesting tissue from the other knee (hamstrings tendon, quadriceps tendon, iliotibial band, patella tendon), synthetic ligaments (LARS – see below), and allografts (other persons donated tissues stored in a tissue bank).
The LARS Ligament is an artificial ligament scaffold, designed and developed in France, which derives its name from the Ligament Advanced Reinforcement System. It is made of polyester (polyethylene terephthalate [PET]) fibers. There are a number of different LARS graft options available to reconstruct all ligaments across the knee as the need arises, but in Dr Gallagher’s experience and practice, ligament reconstruction is almost always best performed using a biological (non-synthetic) graft option.
There are a limited number of exceptions where LARS may become a consideration as a graft source, including some cases of PCL reconstruction, multiple ligament injuries and revision ligament reconstruction where native autogenous (patients’ own tissue or autograft) graft choices are limited or inadequate and use of allograft (other patients tissue) is being considered as well. The accelerated rehabilitation possible with use of LARS also makes it attractive to those athletes with a high degree of motivation and desire to rehabilitate and return to sport within the same season as when they sustained their injury.
Careful consideration is needed before patients attempt to have their knee reconstruction performed using this “rehabilitation shortcut” technique, as by doing so they are committing to having a mechanical non-biological graft which may achieve all of their short term objectives and rapid return to sport and other commitments , but may present additional difficulties with regaining full range of motion, experiencing an audible squeak, and being at risk for eventually failing as a non-vascularised, non incorporated synthetic graft.
The LARS ligament is generally best considered where the ligament being reconstructed still has a reasonable volume of tissue present and needs augmenting, rather than being absent altogether.
The LARS ligament has a central or “intra-articular” portion composed of longitudinal free fibres and a solid bundle at either end for fixation into bone. Use of LARS ligament for reconstructive surgery, is considered on an individual needs basis, with very select indications.
Where it is used, fewer and smaller incisions are employed, and after an initial period of rest and splinting to allow wounds to heal and graft fixation to be achieved, an accelerated rehabilitation protocol is possible as graft elongation is less of a concern as compared to when using biological grafts.
Rehabilitation following multiple ligament reconstructions is a balancing act between ensuring that the knee does not become excessively stiff whilst at the same time avoiding stretching or damaging the structures reconstructed.
This is heavily reliant upon a careful consideration of the ligaments injured, ligaments reconstructed, the graft types and fixation devices used and quality of the patients tissues and bone stock.
The knowledge of an experienced surgeon and physiotherapist and ready communication between the two is essential to ensuring that the best possible result is achieved in this situation, which is often the ultimate test of reconstructive surgery and the rehabilitation efforts that follow.