One of the four major ligaments of the knee, the medial collateral ligament, is a broad, flat, band-like ligament that runs from the medial condyle of the femur to the medial aspect of the shaft of the tibia, where it attaches just above the groove of the semimembranosus muscle attachment (Fig. 140.1). The ligament also attaches to the edge of the medial semilunar cartilage. The ligament is susceptible to strain at the joint line or avulsion at its origin or insertion. The medial collateral ligament is frequently injured from falls with the leg in valgus and externally rotated, typically during snow skiing accidents or as the result of tackles in American football (Fig. 140.2). The pain of medial collateral ligament damage is localized to the medial knee and is made worse with passive valgus and external rotation of the knee. Activity, especially involving flexion and external rotation of the knee, will exacerbate the pain. Local heat and decreased activity may provide a modicum of relief. Sleep disturbance is common in patients suffering from trauma to the medial collateral ligament of the knee. Coexistent bursitis, tendonitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee joint making clinical diagnosis difficult.

Plain radiographs are indicated in all patients who present with medial collateral ligament pain (Fig. 140.3). Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging (MRI) and ultrasound imaging of the knee are indicated if internal derangement or occult mass or tumor is suspected as well as to confirm the diagnosis of suspected medical collateral ligament injury (Fig. 140.4). Bone scan may be useful to identify occult stress fractures involving the joint, especially if trauma has occurred.

The medial collateral ligament, which is also known as the tibial collateral ligament, is a broad, flat, band-like ligament that runs from the medial condyle of the femur to the medial aspect of the shaft of the tibia, where it attaches just above the groove of the semimembranosus muscle attachment (see Fig. 140.1). It also attaches to the edge of the medial meniscus (Fig. 140.5). The medial collateral ligament is crossed at its lower part by the tendons of the sartorius, gracilis, and semitendinosus muscles. A bursa is between these tendons and the medial collateral ligament and is subject to inflammation if the ligament or tendons are traumatized (see Fig. 140.1).

The benefits, risks, and alternative treatments are explained to the patient, and informed consent is obtained. The patient is then placed in the supine position with the lower extremity externally rotated (Fig. 140.6). The skin overlying the medial collateral ligament is then prepped with antiseptic solution. A sterile syringe containing 2.0 mL of 0.25% preservative-free bupivacaine and 40 mg of methylprednisolone is attached to a 1½-inch, 22-gauge needle using strict aseptic technique. A high-frequency linear ultrasound transducer is placed over the medial collateral ligament in the longitudinal plane (Fig. 140.7). A survey scan is taken, which demonstrates the thick hyperechoic filaments of the medial collateral ligament and the bony contours of the medial margins of the femur and tibia (Fig. 140.8). The medial meniscus is visualized as a triangular-shaped hyperechoic structure resting between the bony medial margins of the femur and tibia and beneath the medial collateral ligament (Fig. 140.9). After the medial collateral ligament is identified, the needle is placed through the skin ˜1 cm above the middle of the longitudinally placed transducer and is then advanced using an outof-plane approach with the needle trajectory adjusted under real-time ultrasound guidance to place the needle tip within proximity to the medial collateral ligament but not within the substance of the ligament (Fig. 140.10). When the tip of needle is thought to be in satisfactory position, a small amount of local anesthetic and steroid is injected under realtime ultrasound guidance to confirm that the needle tip is not within the substance of the medial collateral ligament. There should be minimal resistance to injection. After intraarticular needle tip placement is confirmed, the remainder of the contents of the syringe is slowly injected. If synechiae, loculations, or calcifications are present, the needle may have to be repositioned to ensure that the entire intra-articular
space is treated. The needle is then removed, and a sterile pressure dressing and ice pack are placed at the injection site.