Introduction
The medial collateral ligament (MCL), with its proximal and distal divisions superficially, meniscofemoral and meniscotibial divisions deep, is one of the primary structures of the medial knee (Wijdicks, Griffith, Johansen, Engbretsen, & LaPrade, 2010). This complex ligament is the primary medial stabilizer, providing static and dynamic resistance to direct valgus stress as well as contributing to the resistance of rotary forces and anterior-posterior translation (Marchant et al., 2011).
Damage to the MCL is one of the most common knee injuries, especially in those patients reporting an external trauma or forces resulting in valgus stress, with or without rotation of the knee (Kastelein et al., 2008; Phisitkul, James, Wolf, & Amendola, 2006; Schein et al., 2012). Similar mechanisms of injury are reported with meniscus and anterior and posterior cruciate ligament, as well as posterior-medial corner injuries that may occur in conjunction with MCL injury (Fetto & Marshall, 1978; Jacobson & Chi, 2006; Schein et al., 2012). Prognosis following MCL injury inversely correlates with severity and is significantly influenced by concurrent compromise of other ligaments, particularly the anterior cruciate ligament (Azar, 2006; Fetto & Marshall, 1978; Jacobson & Chi, 2006).
Case Presentation
A 50-year-old man presented to this orthopaedic provider approximately 1 month after sustaining injury to the left knee. He reported tripping over a metal support beam, causing a forceful twisting and valgus-type injury of the knee. He noted immediate pain and swelling that prevented him from weight bearing. He was taken to a local emergency department and told that he had "pulled something." The healthcare providers provided a knee immobilizer, crutches, and pain medication. He was instructed to follow up with orthopaedics. He noted issues with pending worker's compensation claim as to the delayed follow-up.
Upon presentation, he reported continued medial knee pain requiring Norco for management. Symptoms aggravated with any weight-bearing activities. Immobilizer and crutches were described as "uncomfortable" and "difficult to use" and thus he had discontinued their use and purchased a knee sleeve. He noted continued feeling of instability with weight-bearing activities, continued daily knee swelling, sometimes involving the lower leg, and bruising of the medial knee that had subsequently resolved. Pain improved, but not completely resolved, when at rest. He described aching and throbbing sensations at night that sometimes kept him from sleep. He denied numbness, tingling, or other distal symptoms.
On physical examination, he was found to be alert, oriented, affect appropriate, and in no apparent distress. He displayed an antalgic gait, lacking appropriate knee extension into heel strike, without use of an assistive device. Tenderness about the medial knee, most notable overlying the medial aspect of the medial femoral condyle. Pain limited his range of motion, initially tolerating 10[degrees]-100[degrees] with painful end ranges. Knee was grossly unstable with valgus stress with reported pain on testing. Although painful, he was able to perform a straight leg raise without extensor lag. He displayed a positive bounce home, McMurray and pivot-shift. He was found to be distally neurovascularly intact.
Radiographic evaluation included anteroposterior, lateral, and sunrise views of the left knee. Findings were evident for an avulsion fracture of the femoral attachment of the MCL as well as moderate to severe, tricompartmental degenerative joint disease/osteoarthritis (see Figure 1). With these physical examinations and radiographic findings, the patient was referred for magnetic resonance imaging.
Magnetic resonance imaging is the most useful adjunct modality to evaluate the full extent of soft tissue, cartilage, and/or osseous injury (Jacobson & Chi, 2006; Schein et al., 2012). Medial knee injuries are often associated with concomitant ligament injuries, as well as meniscus pathology, which must also be treated appropriately to achieve optimal outcomes (Azar, 2006). This patient's magnetic resonance image confirmed the presence of MCL avulsion and tricompartmental osteoarthritis, without convincing evidence of other ligament pathology (see Figure 2).
Management
Nonoperative treatment has long been reported with favorable outcomes, consensus being it is the first step in the management of acute, isolated MCL injuries (Azar, 2006; Fetto & Marshall, 1978; Phisitkul et al., 2006; Wijdicks et al., 2010) The patient was provided a hinged knee brace and referral to physical therapy with goals of improving range of motion, quadriceps strength, and gait mechanics. Unfortunately, approval via his worker's compensation claim was delayed and thus was unable to initiate therapy previous to his 1-month follow-up. At the 1-month follow-up, he noted continued pain and feeling of instability. Radiographic evaluation showed no evident healing and examination confirmed continued instability of the knee. Given these findings, in conjunction with the presence of osteoarthritis of the knee, he was referred to an orthopaedic surgeon for discussion of MCL repair versus the potential for total knee arthroplasty (Azar, 2006; Marchant et al., 2011; Wijdicks et al., 2010).
Discussion
A thorough understanding of anatomy and biomechanics of the knee, in conjunction with physical examination findings, is paramount in ascertaining the full extent of injury, thus guiding treatment decisions (Jacobson & Chi, 2006; Phisitkul et al., 2006). The existing consensus is that isolated MCL injuries can be treated nonoperatively (Azar, 2006; Fetto & Marshall, 1978; Phisitkul et al., 2006; Wijdicks et al., 2010). The goals of conservative treatment are the alleviation of symptoms and return to prior level of function. The advanced practice nurse should be aware that chronic instability, or finding concurrent ligament injuries, may require operative intervention, and those patients are best served being referred to an orthopaedic surgeon for consultation (Azar, 2006; Jacobson & Chi, 2006; Marchant et al., 2011).
References