DEFINITION

A medial collateral ligament (MCL) injury usually is the result of a valgus stress on the knee.

Forced external rotation injuries with a valgus component also have been described as a mechanism that can disrupt the MCL.

Although the direct valgus force is more likely to injure the superficial MCL, external rotation and valgus stress often causes additional injuries to the deep MCL, the anterior cruciate ligament (ACL), the posteromedial corner, or the posterior oblique ligament (POL).

The most common combined injury is an ACL and MCL injury followed by meniscus injuries.

 

 

ANATOMY

 

Both static and dynamic forces are responsible for resisting valgus forces at the knee. The major static stabilizers of the medial knee include the POL, superficial MCL, and deep MCL. The major dynamic forces that resist valgus load include the medial head of the gastrocnemius, vastus medialis, pes anserinus, and semimembranosus.

 

The medial side of the knee can be divided into three layers: superficial (I), intermediate (II), and deep (III).

 

 

Layer I: The crural fascia invests the quadriceps fascia and the sartorius proximally and the pes anserinus and tibial periosteum distally.

 

Layer II: The superficial MCL and the medial patellofemoral ligament (MPFL) lies between layers II and III.

 

Layer III: the deep MCL (ie, the meniscotibial and meniscofemoral ligaments) and the posteromedial corner (ie, semimembranosus and POL)

 

The superficial MCL originates from the medial femoral epicondyle. It inserts approximately 4 to 6 cm distal to the medial joint line and can be divided into an anterior and a posterior portion. The anterior portion tightens in flexion; the posterior portion tightens in extension.

 

The deep MCL tightens in knee flexion and is lax in full knee extension.

 

The posteromedial corner provides rotational stability to the medial side of the knee. Injuries to these structures cause anteromedial rotatory instability.

 

The semimembranosus has five main attachments to the posterior capsule of the knee:

 

 

 

Pars reflexa, attaching directly to the proximal medial tibia Direct arm, attaching to the posteromedial tibia

 

Insertion to the proximal medial capsule

 

Attachment to the POL

 

Attachment to the popliteus aponeurosis

 

PATHOGENESIS

 

The typical mechanism for an MCL injury is a valgus stress acting on the knee joint with the foot planted. This mechanism often leads to a disruption of the deep and superficial MCL.

 

If an external rotational component is added, a disruption of additional restraints such as the ACL and the posteromedial corner is likely. In particular, an injury to the POL indicates a significant capsular injury that

leads to a higher grade of medial and rotatory instability.4

 

MCL injuries can be partial or complete. A complete MCL injury involves disruption of the superficial and deep MCL and usually results initially in inability to ambulate.

 

MCL injuries can be on either the femoral or tibial side. It is important for the treatment algorithm to differentiate whether the tear involves the femoral origin of the MCL or the tibial insertion.

 

NATURAL HISTORY

 

Acute isolated MCL injuries usually are treated nonoperatively with protective weight bearing and bracing for 2 to 6 weeks.

 

 

In particular, partial tears of the MCL (grade 1 or 2) heal well with conservative treatment.

 

Complete MCL injuries (grade 3 injuries) initially can be treated conservatively if they are femoral-based ligament ruptures.4

 

A complete tibial-sided MCL avulsion with POL extension is less likely to tighten up with nonoperative management and often requires repair or reconstruction. Rarely seen as an isolated injury.

 

Grade 3 MCL injuries in combination with other ligament injuries of the knee may require acute surgical repair in case of a complete tibial avulsion with POL extension.7

PATIENT HISTORY AND PHYSICAL FINDINGS

 

A description of the mechanism of injury (eg, valgus mechanism, valgus rotation mechanism) must be elicited.

 

The examination includes inspection for peripheral hematoma along the medial side of the knee and palpation of hamstrings, joint line (meniscal injury), and the femoral origin and tibial insertion of the MCL for stability testing.

 

Acute evaluation of an MCL is ideal, if possible, before muscle spasms occur.

 

A thorough evaluation of the neurovascular status of the extremity is imperative to avoid missing a limb-threatening situation.

 

Valgus stress at 0 and 30 degrees: grade 1 (0- to 4-mm opening) and grade 2 (5- to 9-mm opening) injuries usually can be treated nonoperatively; grade 3 (10- to 15-mm opening)

 

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injuries are associated with other ligament tears (ie, ACL, POL) in over 75% of cases.

 

 

Slocum modified anterior drawer test: Disruption of the deep MCL allows the meniscus to move freely and allows the medial tibial plateau to rotate anteriorly, leading to an increased prominence of the medial tibial condyle.

 

Anterior drawer test in external rotation: Disruption of the MCL alone should not lead to an increased anteromedial translation. An increased anteromedial translation indicates an anteromedial rotatory instability that involves an injury of the posteromedial capsule (eg, POL, semimembranosus attachments as well as deep MCL).

 

A thorough examination of the knee should always include the following assessments:

 

 

Meniscus: tenderness directly at the joint line is a sensitive sign for a meniscus injury. The McMurray test or a flexion-rotation-compression maneuver may accentuate medial joint line pain, suggesting a medial meniscus tear. (This test may not be helpful in an acute setting.)

 

ACL: An immediate (within 24 hours) intra-articular effusion after the injury indicates a high likelihood of ACL injury. Positive Lachman test (acute) and pivot shift test (chronic) indicate an associated ACL tear. In the acute or subacute setting, these tests may be difficult to perform. Instrumented laxity testing (KT-1000) may be helpful in these situations. An increased valgus laxity in full extension almost always indicates one or both of the cruciate ligaments are injured. Some surgeons use this as an indication for subacute/acute MCL repair.

 

Posterior cruciate ligament (PCL): A positive posterior drawer test indicates a PCL injury. The end point is important to assess the grade of the PCL injury.

 

Patella: The apprehension sign and localized tenderness on the lateral or medial aspect of the patella or the lateral trochlea indicates a possible patella dislocation, which can go hand-in-hand with an intra-articular effusion. Tenderness at the medial femoral epicondyle also can be caused by an avulsion of the MPFL.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs help to assess the bony integrity of the knee joint. They may show indirect signs of ligament injury (eg, Segond fracture), but they usually are not helpful for the diagnosis of an acute MCL injury.

 

 

 

 

FIG 1 • A. Pellegrini-Stieda lesion indicating chronic MCL insufficiency. B. Arthroscopic ipsilateral medial

drive-through sign. The joint space opens more than 10 mm and permits complete passage of the arthroscope into the back of the medial compartment. C. The arthroscopic examination permits direct evaluation of the injured structure, including the POL and tibial- or femoral-sided deep MCL. The meniscus tends to follow the noninjured structure. A proximal meniscal lift-off suggests a tibial-sided tear, whereas a distal lift-off suggests a femoral-sided tear. (continued)

 

 

In the case of chronic MCL instability, a Pellegrini-Stieda lesion (bony spur originating at the femoral origin of the MCL, usually visualized on the flexion weightbearing posteroanterior radiograph) may be present (FIG 1A).

 

Magnetic resonance imaging (MRI) with or without contrast is helpful to identify MCL damage.

 

Edema or MCL disruption can be visualized.

 

The location and extent of the disruption (femoral vs. tibial) can be determined.

 

The amount of bone bruising can be assessed, and associated pathology (eg, meniscal tears, ACL tears, posteromedial corner injuries) can be visualized.

 

Isolated grades 1 and 2 MCL injuries can be diagnosed clinically; and generally, an MRI is not indicated unless the patient has an intra-articular effusion or signs of other ligament injury.

 

Arthroscopic examination is a formidable tool to assess the true nature of the MCL injury.

 

 

An ipsilateral “drive-through” sign (ie, opening of the medial compartment of more than 10 mm, allowing for complete insertion of the arthroscope into the medial compartment [FIG 1B]) should arouse suspicion for a significant MCL injury that may require repair or reconstruction. If one can see easily the entire medial meniscus posterior horn, then you have significant medial opening. If the meniscus follows the femur, you have a tibial-sided lesion; if the meniscus stays with the tibia and the gap is above the meniscus, you have a femoralsided lesion.

 

The location of the acute or chronic injury—femoral or tibial—also can be evaluated. Separate injuries of the POL also can be visualized (FIG 1C-F).

 

DIFFERENTIAL DIAGNOSIS

 

 

Medial meniscus tear ACL tear

 

 

Posteromedial corner injury Patella dislocation

 

Pes-anserine bursitis

 

 

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FIG 1 • (continued) D. Additional image of arthroscopic ipsilateral medial drive-through sign. E. Post-MCL fixation, medial drive-through has been eliminated. F. Seventy-degree scope in Gillquist position with nice view of torn POL (black arrow). Medial meniscus (red arrow). G. Suture repair, from outside in, of the POL. H. Tibial-sided avulsion of MCL into the knee joint.

 

NONOPERATIVE MANAGEMENT

Grades 1 and 2 Medial Collateral Ligament Sprains

 

Rest, ice, compression, and elevation (RICE) for 24 hours or until swelling is controlled.

 

Once swelling is controlled, partial weight bearing, range-of-motion (ROM) exercises, and electrical stimulation can be started. A simple hinged brace is applied.

 

Full weight bearing can be allowed once ROM over 90 degrees of flexion as well as motor control of the thigh musculature has been demonstrated.3,6

 

Once full ROM and 80% strength of the opposite side have been achieved, closed kinetic chain exercises, jogging, and treadmill exercise may begin.

 

 

In athletes, a return to sport-specific training is safe once 80% of the maximum running speed is achieved.3,6 Return to play depends on the grade of the sprain:

 

Grade 1: 10 to 14 days

 

Grade 2: 3 to 4 weeks

 

Grade 3 Medial Collateral Ligament Sprains

 

 

MCL sprains without associated ACL or meniscus tear account for less than 20% of all grade 3 sprains. The knee is reevaluated frequently (every 7 to 10 days) to assess whether the MCL “tightens up.” Tibial-

sided, complete avulsions of the MCL may not heal and require acute surgical repair if they do not tighten up within the first 4 weeks (FIG 1G,H).

 

It is important to check for combined ACL/MCL tears. Grade 3 MCL tears with POL extension in combination with an acute ACL tear often require surgical repair or even augmentation because of the rotational laxity that results from the POL injury.

 

RICE is maintained until the swelling is controlled.

 

 

Zero to 4 weeks: restoration of ROM, weight bearing is often limited for 4 to 6 weeks

 

Four to 6 weeks: full ROM and weight bearing is achieved by the end of week 6, full quadriceps/hamstring strengths, closed kinetic chain exercises, stair-stepper exercise, proprioceptive exercises

 

Six to 10 weeks: full squatting, jogging, light agility drills, slow return to competition, brace discontinued for noncontact sports

 

SURGICAL MANAGEMENT

Preoperative Planning

 

All radiographs and MRIs are reviewed before surgery.

 

Associated injuries must be addressed at the same time and often determine the sequence of the surgery (PCL before ACL before MCL).

 

In case of a chronic MCL injury and associated ACL or PCL tears, the appropriate allograft tissue must be available.

 

Examination under anesthesia must include a full ligamentous examination (ie, Lachman test, pivot shift test, varus/valgus stress test, dial test, anteromedial drawer test, patella stability).

 

Positioning

 

The patient is positioned in the supine position.

 

We prefer to use an arthroscopic leg holder. This enables the surgeon to sit during the MCL reconstruction and balance the patient's foot on his or her knee to adjust the flexion angle. It also allows the nonoperative extremity to be well out of the way to work on the medial side of the knee.

 

The procedure also can be performed on a regular operating table with the patient in the supine position with a bolster positioned under the knee.

 

Approach

 

We use the 6- to 8-cm midmedial approach over the posterior aspect of the superficial MCL.

 

 

 

 

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TECHNIQUES

• Incision and Dissection for Midmedial Approach

The incision should be centered over the joint line and can be extended proximally or distally, as necessary.

In case of a proximal extension, the incision should be slightly curved posteriorly over the medial femoral epicondyle.

Retraction of the skin exposes the sartorius fascia, which must be split in a longitudinal or T-fashion. Underneath the sartorius fascia (layer I), the superficial MCL is exposed.

The posterior border of the superficial MCL and the anterior border of the POL are identified, and a vertical incision is made along this interval, exposing the deep MCL.

 

TECH FIG 1 • A. None of the tendons or ligaments attach directly on the osseous landmarks. B. POL femoral attachment is 1.4 mm distal and 2.9 mm anterior to the GT. Distance between the MCL and POL

 

attachment sites is 11 mm. C. POL anatomy: Superficial arm: thin fascial expansion that runs parallel and posterior to the MCL. Central arm: largest and thickest part. Firm attachment to the tibia and medial meniscus (MM). Capsular arm: thin fascial expansion, which blends with the posteromedial capsule.

AMT, adductor magnus tendon; AT, adductor tubercle; MGT, medial head of gastrocnemius; GT, gastrocnemius tubercle; ME, medial epicondyle; POL, posterior oblique ligament; MCL, medial collateral ligament; SM, semimembranosus. (Courtesy of Charles H. Brown, Jr., MD.)

 

 

This incision can be carried down through the capsule to expose the meniscal attachments. An avulsion of the POL from the posterior capsule may be identified in select cases.

 

A plane can be developed between the superficial and the deep MCL.

 

This plane allows for a separate repair of the deep MCL against the POL to tension the POL.

 

It also exposes the medial tibial plateau and allows for easy placement of a suture anchor for a repair of the deep MCL at the level of the joint line, which is critical.

 

 

A spinal needle is often useful to help localize the medial joint line. Anatomy of the medial side of the knee (TECH FIG 1A-C)

• Acute Repair of Tibial-Sided Isolated Grade 3 Medial Collateral Ligament Tears

   

  Tibial avulsion is documented arthroscopically by a positive drive-through sign (>10 mm of medial opening).

   

  The medial meniscus lifts off from the tibial plateau during this maneuver, revealing the tibial-sided tear of the deep MCL.

   

  A limited direct medial approach is performed through a 5- to 6-cm incision along the posterior aspect of the MCL.

   

  The sartorius fascia is divided, which usually exposes acute avulsion of the deep MCL from the tibia. The superficial MCL also usually is torn but can be sharply divided from the deep MCL.

   

  An alternative is to divide the sartorial fascia on its superior and inferior border and work between the two windows to repair the MCL.

   

  Three or four double-loaded suture anchors are then placed along the medial border of the tibial plateau about 5 mm below the joint line.

   

  The meniscotibial ligament can be secured to the suture anchors, allowing for an excellent repair of the deep MCL along with the coronary ligament and medial meniscus.

   

  The sutures can be left long after the initial knots are tied and also can be used to tie down the superficial MCL (TECH FIG 2).

   

  The superficial MCL is subsequently repaired anatomically to its tibial insertion with suture anchors/spiked screw and washer or staple.

   

  The POL can be imbricated, if patulous, in a pants-over-vest fashion to the repaired MCL.

   

   

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  TECH FIG 2 • Acute suture anchor repair of the deep MCL with imbrication of the capsule. The suture anchors are placed just distal to the joint surface and allow for reefing of the torn deep MCL to the proximal tibia.

• Autograft Reconstruction of Isolated Chronic Medial Collateral Ligament Tears

   

  Reconstruction of the superficial MCL requires stabilization of the central pivot of the knee. Any associated ACL or PCL injury must be addressed simultaneously with or before the MCL reconstruction.

   

  The reconstruction includes repair and tightening of the deep MCL/POL complex, which should be tightened at 0 degree. The superficial MCL reconstruction should be tightened at 30 degrees of flexion.

   

  The deep MCL and POL can be identified through the midmedial incision and can be retightened using suture anchors, as with the primary repair of the MCL (TECH FIG 3A,B).

   

   

   

  TECH FIG 3 • A. Medial incision allowing access to freshly avulsed MCL. B. The sartorius fascia is split, and the superficial MCL attachment is recovered. C,D. Reconstruction of the MCL over a femoral screw and washer using a semitendinosus allo- or autograft. C. Routing of the semitendinosus tendon and the skin incisions. D. The final tensioned construct and the screw and washer at the origin of the MCL on the medial femoral epicondyle. (Courtesy of Mark D. Miller, MD.)

   

   

   

  Chronic MCL injuries should be augmented with a superficial MCL reconstruction. Autograft MCL reconstruction can be done using a Bosworth reconstruction.

   

  In the Bosworth reconstruction, a semitendinosus tendon is harvested using the closed tendon stripper. The femoral origin of the MCL is identified. A K-wire is inserted into the insertion site, and isometry is tested to avoid a flexion contracture after the superficial MCL repair.

   

  Once the isometric site is identified, the semitendinosus can be routed around a screw and washer femorally and can be attached distally using a staple or bone tunnels. This allows for reconstruction of the posterior and anterior bundles of the superficial MCL (TECH FIG 3C,D).

   

   

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• Allograft Reconstruction of Isolated Chronic Medial Collateral Ligament Tears

   

  Borden et al1 have described an allograft reconstruction of the MCL.

   

   

  A double anterior tibialis tendon or a split Achilles or patella tendon can be used for this technique. The surgical approach is the same as that described for autograft reconstruction.

   

  The origin of the MCL on the medial epicondyle must be identified. The femoral fixation is positioned at the anatomic insertion of the MCL.

   

  Fixation can be achieved in various ways—bone tunnel using a soft tissue screw fixation, bone block using an interference screw fixation, bone trough, or screw and washer fixation.

   

  The distal tibial fixation has to reconstruct the anterior and posterior aspect of the native MCL (TECH FIG 4).

   

   

   

  TECH FIG 4 • Double-bundle MCL allograft reconstruction technique using bioabsorbable screw fixation. (Courtesy of Mark D. Miller, MD.)

   

   

  The allograft can be anchored anteriorly and posteriorly along the anatomic attachment sites using an interference screw (as depicted), a screw and washer, or a staple.

  Distal Fixation in Chronic Injuries

   

  In chronic MCL injuries, it often is the distal end of the MCL that has failed to heal.

   

  Using the standard medial approach, the distal end of the MCL often can be identified (TECH FIG 5A).

   

  This attachment can be used in the reconstruction if the length is adequate; if not, it can be sutured to the reconstruction.

   

  The allograft is then fixed femorally (as described earlier) and routed along the course of the superficial MCL (TECH FIG 5B).

   

  The posterior and anterior portions of the superficial MCL can then be individually attached to the tibia.

   

   

   

  TECH FIG 5 • A. Medial incision. The chronically disrupted MCL stump can be visualized through the sartorius fascia. B. An Achilles tendon allograft has been sized to fit in a bone trough at the epicondylar origin of the MCL (depth gauge shown in preparation for screw fixation of the bone block). The allograft has been routed along the course of the MCL and fans out to provide the posterior and anterior portion of the MCL. (Courtesy of Mark D. Miller, MD.)

• Allograft Reconstruction of Isolated Chronic Medial Collateral Ligament Tears with Reconstruction of the Posterior Oblique Ligament

 

An alternate method used in chronic MCL reconstructions is to reconstruct both the superficial MCL and the POL (see FIG 1A-C for anatomy).2,5

 

A medial parapatellar skin incision is made and the skin and sartorius fascia are kept as one layer (TECH FIG 6A,B).

 

Working between the window of the upper and lower border of the hamstrings the tibial insertion of the superficial MCL and the POL central arm sites are marked. The femoral insertions of the superficial MCL and the POL central arm sites are also marked (TECH FIG 6C-F).

 

 

The tibial insertion of the superficial MCL is located 61 mm distal to the tibial plateau (TECH FIG 6C). The tibial tunnels should be tapped (TECH FIG 6D).

 

Two semitendinosus or tibialis tendon allografts are cut to 16 cm for the MCL, 12 cm for the POL (TECH FIG 6G).

 

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The MCL and POL grafts fixed first on the tibial side with 7- × 25-mm bioabsorbable screws (TECH FIG 6H)

 

The MCL and POL grafts passed into their respective femoral tunnels and the medial reconstruction tensioned prior to ACL reconstruction.

 

 

 

TECH FIG 6 • A. Medial parapatellar incision is shown. B. Sartorial fascia shown elevated as one flap with the skin. Black arrow depicting sartorial fascia below skin. C. Tibial insertion of the MCL ˜61 mm distal to the joint line (red arrow). Semimembranosus tendon (green star). Tibial insertion of the central arm of the POL (blue arrow). D. Tibial tunnel tapped. E. Tibial insertion of MCL (black arrow), tibial insertion of the central arm of the POL (blue arrow), femoral insertion of MCL (green arrow), femoral

insertion of the central arm of the POL (yellow arrow), and superficial MCL (red star). F. Tibial insertion

of MCL (black arrow), tibial insertion of the central arm of the POL (blue arrow), femoral insertion of MCL (green arrow), femoral insertion of the central arm of the POL (yellow arrow), and superficial MCL (red star). Semimembranosus being retracted inferiorly to reveal tibial insertion of POL. G. Two semitendinosus or tibialis tendon allografts are cut to 16 cm for the MCL, 12 cm for the POL. H. MCL and POL grafts fixed first on the tibial side with 7- × 25-mm bioabsorbable screws. I-K. Grafts fixed with 7- × 25-mm bioabsorbable screws on the femoral side, with completed reconstruction. (B,F-K: Courtesy of Charles H. Brown, Jr., MD.)

MCL tensioned at 30 degrees, neutral tibial rotation, POL tensioned at full extension Grafts fixed with 7- × 25-mm bioabsorbable screws on the femoral side (TECH FIG 6I-K)

 

 

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PEARLS AND PITFALLS

 

Grade ▪ Obtain MRI and check for tibial-sided avulsions, which may require surgical repair.

3 ▪ Be sure to follow patients closely if conservative management is chosen. The MCL MCL should tighten up after 4 to 6 weeks. If it fails to tighten in valgus stress, reconstruction tear may be necessary.

• Diagnose associated injuries with clinical examination and MRI.

• When doing multiple ligament surgery, make sure that the ACL and PCL tunnels have been drilled before positioning of the MCL tunnels.

 

 

POSTOPERATIVE CARE

The postoperative course is as follows:

 

Zero to 3 weeks: touchdown weightbearing, hinged brace locked in 0 to 90 degrees of flexion, isometric quad strengthening (quad squeezes, straight-leg raises)

Three to 6 weeks: touchdown weightbearing, ROM free in brace, quadriceps/hamstring strengthening. The repair must be protected.

Six to 12 weeks: Patient allowed to weight bear, the brace is maintained. Light jogging and stair-stepper exercise are begun toward the end of this phase.

12 to 18 weeks: Progressive return to sports with sportspecific drills and return to play once 90% of quadriceps and hamstring strength and 75% of maximum running speed have been regained. Telescoping brace is discontinued and patient is placed in an MCL unloading-type brace for all contact sports for the first year from surgery.

 

 

OUTCOMES

Grades 1 and 2 MCL sprains should be treated nonoperatively. The average time to return to athletic

 

 

activities is between 19 and 23 days, on average, for grades 1 and 2 injuries, respectively.3

Grade 3 MCL sprains can be treated nonoperatively with good success if several pitfalls are avoided: Conservative treatment of an isolated grade 3 MCL injury allows most athletes to return to play after an average of 34 days.3

Tibial-side avulsions of the deep and superficial MCL with POL extension tend to progress toward

chronic MCL laxity. Either early surgical treatment or repetitive clinical examination to assess the gradual return of valgus stability over the course of 4 weeks is advisable. If valgus laxity is still present after 4 weeks, surgical treatment is advised.

Concomitant ACL injuries are common and often will result in residual chronic MCL laxity if treated nonoperatively.

 

 

COMPLICATIONS

Failure to diagnose associated ligament, meniscal, and articular cartilage injuries Deep venous thrombosis

Infection Arthrofibrosis

 

 

REFERENCES

1. Borden PS, Kantaras AT, Caborn DN. Medial collateral ligament reconstruction with allograft using a double-bundle technique. Arthroscopy 2002;18(4):E19.

    

    

2. Coobs BR, Wijdicks CA, Armitage BM, et al. An in vitro analysis of an anatomical knee reconstruction. Am J Sports Med 2010;38(2): 339-347.

    

    

3. Giannotti BF, Rudy T, Graziano J. The non-surgical management of isolated medial collateral ligament injuries of the knee. Sports Med Arthr 2006;14:74-77.

    

    

4. Indelicato PA. Isolated medial collateral ligament injuries in the knee. J Am Acad Orthop Surg 1995;3:9-14.

    

    

5. LaPrade, RF, Engebretson AH, Ly TY, et al. The anatomy of the medial part of the knee. J Bone Joint Surg Am 2007;89(9):2000-2010.

    

    

6. Reider B, Sathy MR, Talkington J, et al. Treatment of isolated medial collateral ligament injuries in athletes with early functional rehabilitation: a five-year follow-up study. Am J Sports Med 1994;22:470-477.

    

    

7. Wilson TC, Satterfield WH, Johnson DL. Medial collateral ligament “tibial” injuries: indication for acute repair. Orthopedics 2004;27: 389-393.