Collateral Ligament Pathology Treatment & Management

Medial collateral ligament injuries of the knee

In general, the treatment of isolated MCL injuries is conservative and based on functional results, with a period of protection and then aggressive strengthening and functional rehabilitation. Return to activity usually is allowed when the knee is at full (or at least 80%) strength, full range of motion, and causing no pain.^[23]

In grade 1 injuries, a period of protection with a hinged knee brace or hinged neoprene sleeve and weight bearing as tolerated is recommended initially. Physical therapy, with modalities and strengthening, can optimize an early return to activities such as sports and work. Many patients probably can go to a home- or gym-based exercise program of quadriceps and hamstring strengthening. Proprioceptive training probably would also help minimize future problems and allow for the most efficient return of high levels of activity with confidence.

Grade 2 injuries usually require a 2- to 4-week period of protected weight bearing, and hinged knee brace protection for 6 weeks. Physical therapy is very helpful in regaining strength and function in this situation.

Grade 3 isolated injuries are not as common and usually involve consideration of other simultaneous injuries. If the injury appears to be truly isolated, conservative treatment has been very successful. A hinged knee brace with 4 weeks of non-weight bearing and subsequent aggressive rehabilitation is usually optimal.

As discussed below, ACL/MCL injuries are prone to motion problems and arthrofibrosis. Initial management should focus on protection of the MCL with a hinged knee brace, achieving range of motion (especially terminal extension), and then treating the ACL with individualized treatment according to the functional demands of the patient. A grossly lax MCL demands careful search for other ligament injuries (including possible knee dislocation) and warrants consideration of repair of the MCL and posteromedial capsule.

Medial collateral ligament and anterior cruciate ligament injuries

Often, the MCL is injured at the same time as the ACL. This combination injury has been found to increase the potential for a stiff knee, especially if operative treatment is undertaken on an early basis. At times, even a nonoperative approach to this combination of injuries can result in an arthrofibrotic knee, which often includes a relatively immobile patella and stiff medial retinaculum.

The clinical observations of Jokl in 1984, Shelbourne in 1992,^[15] and Elsasser in 1974 have strongly suggested that the MCL does not need surgical repair in ACL/MCL injuries. In addition, of those patients who did undergo ACL reconstruction with and without MCL repair, the nonoperative group had quicker recovery of motion.^{[15, 24, 25]} True complete capsular tears of the MCL warrant consideration for repair.

Timing of surgery to address ACL injury in the setting of MCL injuries is an important consideration. Clear differences in recovery of range of motion after ACL reconstruction have been demonstrated by Shelbourne and Harner in 1992, in cases involving concomitant MCL injuries. Optimal waiting time is probably about 3 weeks. This author has performed ACL reconstruction successfully in grade 1-2 MCL injuries in a 2-week period as long as the preoperative range of motion is at full extension and to 90 degrees of flexion.

Lateral collateral ligament injuries

Isolated LCL injuries usually are treated easily, but associated injury to other structures of the knee often occur when the LCL is lax, and the knee should be evaluated thoroughly before treatment of an apparently isolated LCL injury is undertaken. LCL injuries that are low grade are well managed with protection in a hinged knee brace and protected weight bearing for 4 weeks, with subsequent rehabilitation. Displaced fractures of the fibular head with associated varus instability are best addressed by fixation of the fracture and early rehabilitation.

Conservative treatment should be strongly considered for isolated posterolateral complex injuries. Posterolateral complex injuries with associated high-grade (3 or 4) PCL injuries present a strong argument for addressing both the PCL and posterolateral injuries.^{[26, 27]} A paucity of data exists, and research to clearly define the efficacy of operative management of PCL/posterolateral complex injuries is minimal, but biomechanical studies clearly support fixation to minimize posterior and rotational translation of the tibia with respect to the femur.^[28]

Grade 1 and 2 isolated posterolateral ligament complex injuries are treated reasonably with a hinged brace initially and immobilization initially at 45 degrees for 3 weeks. Progressive range of motion and weight bearing after 3 weeks as comfort allows enables progression in rehabilitation. Grade 3 posterolateral injuries warrant repair, especially because the results of reconstruction are not as good as those of acute repair.

High-grade (3 or 4) PCL injuries with associated posterolateral injuries often require consideration for repair of the posterolateral corner in association with PCL reconstruction. Reconstruction of the posterolateral corner is considered, especially when associated with chronic PCL injury.

Medial collateral ligament injuries

As mentioned above, rarely is surgical treatment of the medial collateral ligament required. Surgery may be needed to stabilize the medial side of the knee, for example, in multiple ligament injuries such as knee dislocations.^[29] Attention to restoration of the anatomy and avoidance of shortening the superficial portion of the MCL by anchoring the ligament too close to the knee joint are important. If a laceration of the MCL has occurred or an end-to-end repair is performed, Krackow suture technique affords good purchase on both ends. Tying the sutures in extension to avoid flexion contracture is optimal.

Lateral collateral ligament injuries

In the acute knee dislocation, repair of the posterolateral complex can be achieved by direct repair of the injured structures. Surgical approach is dictated by the group of ligaments injured. In any lateral approach, identification and protection of the peroneal nerve is paramount. To avoid capture of the knee in flexion, the knee should be in full extension when tying these sutures. Suture anchors may be needed to help supplement the repair. Postoperative treatment is usually that of a hinged knee brace and progression of range of motion as per the general plan for the combination of ligaments injured. Limited weight bearing is usually necessary to protect the soft-tissue repairs for a 6-week period.

Restoration of the symptomatic chronic posterolateral injuries usually requires stabilization of the posterolateral corner with autogenous tissue, such as the peroneal tenodesis, as described by Clancy; allograft patellar tendon, as described by Noyes; or split Achilles tendon.^{[30, 31, 32]} The author favors the Clancy procedure for its reproducibility, but often the hardware on the lateral side causes symptoms and requires eventual removal.

A good physical examination and radiographic and MRI studies allow for the most accurate evaluation of the injuries involved and approach required.

Using local tissues during surgery to repair the MCL and LCL may not be optimal. The surgeon should be prepared to use other tissues, such as hamstring tendon or allograft, if a problem is anticipated.

Immobilization and functional rehabilitation depend on the procedure performed and the surgeon's confidence in fixation of the tissue that was repaired or reconstructed. General protocol guidelines involve use of a hinged knee brace with varied range of motion allowed, depending on the structures addressed at the time of surgery and the surgeon's confidence in fixation of the repaired or reconstructed structures. Weight bearing usually is allowed progressively over a 6- to 8-week period, with emphasis placed more on motion than strength during this period.

Periodic evaluations at 2- to 4-week intervals are required for both operative and nonoperative management of collateral ligament injuries. Early evaluation of range of motion and then later evaluation for strength are necessary to direct effective and optimal recovery.

For excellent patient education resources, visit eMedicine's Foot, Ankle, Knee, and Hip Center. Also, see eMedicine's patient education articles Knee Injury and Knee Pain.

In general, stiffness is more common than laxity in collateral ligament injuries. In those injuries that are treated with surgery, stiffness is the most common problem. Residual weakness due to noncompliance or heterotopic ossification can occur but is rarely debilitating or symptomatic enough to warrant removal. This is known radiographically as a Stieda-Pellegrini lesion, which is an ossification of the MCL.

As noted above, peroneal nerve injuries can be associated with lateral-sided injuries.

With operative management come the usual risks of infection, neurovascular injury, stiffness, deep venous thrombosis, and anesthetic-related complications.

Outcome is related directly to the severity of the injury and the functional rehabilitation possible. Patients with isolated injuries typically do well if the injuries are managed safely but aggressively. Injuries to the ACL and MCL usually are associated with early return of full extension and patellar mobility and subsequent strength. Results of other multiple ligament injuries are best reviewed in the literature regarding knee dislocations.

Given the excellent results regarding isolated collateral ligament injuries when they are treated conservatively, controversy has waned in this area.

Injuries of the ACL and MCL still generate some discussion, but most authors favor conservative management of MCL injuries in this setting, with ACL reconstruction for appropriate patients. Primary repair of the MCL in this setting has few proponents currently.

Lateral complex injuries are less well defined, and numerous approaches are possible. Timing of the repair of lateral structures if isolated is also still debated. Continued improvement in understanding of the lateral side of the knee and defining the role that the lateral side plays in PCL injuries is ongoing.