Collateral Ligament Pathology Treatment & Management

Updated: Apr 10, 2021
  • Author: Michael P Nogalski, MD; Chief Editor: Thomas M DeBerardino, MD  more...
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Approach Considerations

Conservative management of isolated collateral ligament injuries is the general rule. Reattachment of displaced bony avulsions of the ligaments is a reasonable consideration, as this would allow for early motion in these cases.

The main complication to be avoided in the treatment of collateral ligament injuries is loss of motion and strength. Operative treatment usually is contraindicated in isolated injuries because the results of nonoperative treatment have been shown to be as good as, if not better than, those for surgically treated isolated MCL injuries. [11, 28]

In isolated collateral ligament injuries, conservative treatment usually is indicated, and few, if any, contraindications to conservative management exist. Even if skin conditions (eg, burns, degloving injuries) or other circumstances do not allow for bracing, relative protection usually suffices because these patients have other pressing issues that limit mobility. Interestingly, patients who have severe periarticular soft-tissue injuries usually have considerable stiffness with or without ligamentous injury. Delayed treatment is optimal in this situation because of the stability that may be afforded by exuberant soft-tissue reaction and possible heterotopic ossification. In these situations, early operation may further stimulate the scar response around the joint.

The usual other operative risks, when considered against the excellent outcome with conservative but aggressive functional mobilization and bracing, clearly argue strongly for nonoperative management.


Medical Care

Medial collateral ligament injuries of the knee

In general, the treatment of isolated medial collateral ligament (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. [29]

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.

A case report describes successful treatment of a grade 3 MCL injury with a series of three sequential leukocyte-rich, platelet-rich plasma (LR-PRP) Injections spaced evenly one week apart, in addition to an early physical therapy regimen. The total treatment time was 31 days, compared with the 35-49 days that would be expected in such cases. [30]

As discussed below, combined anterior cruciate ligament (ACL) and 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.

Lateral collateral ligament injuries

Isolated lateral collateral ligament (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) posterior cruciate ligament (PCL) injuries present a strong argument for addressing both the PCL and posterolateral injuries. [31, 32]  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. [33]

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 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, [14]  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. [14, 34, 35]  However, true complete capsular tears of the MCL warrant consideration for repair.


Surgical Care

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. [36]  Attention to restoration of the anatomy and avoidance of shortening the superficial portion of the MCL (which may occur with anchoring of 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. [37, 38, 39]  The author favors the Clancy procedure for its reproducibility, but often the hardware on the lateral side causes symptoms and requires eventual removal.

Medial collateral ligament and anterior cruciate ligament injuries

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.

Kitamura and colleagues, in a study of 37 patients with multiligamentous knee injuries, reported good clinical outcomes and postoperative medial stability at a minimum of 2 years of follow-up with combined MCL and cruciate ligament reconstruction using hamstring tendon autografts. [40]


Preoperative Details

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


Intraoperative Details

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.


Postoperative Details

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.



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.


Long-Term Monitoring

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 patient education information, see Knee Injury and Knee Pain.