Breaststrokers Knee

Breaststrokers Knee – The Clinical Syndrome

Breaststroker’s knee is characterized by pain at the medial aspect of the knee joint. It is the result of repetitive trauma to the medial collateral ligament from excessive valgus and rotational torque forces placed on the medial knee during the whip kick. The whip kick is used by competitive swimmers when performing the breaststroke and, even when performed correctly, subjects the medial collateral ligament and medial meniscus to high levels of valgus stress as the leg is rapidly extended and rotated while at the same time compressing the lateral compartment.

Over time, repetitive microtrauma to the medial collateral ligament results in laxity, joint dysfunction, and pain. 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 where the semimembranosus muscle attaches. It 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.

What are the Symptoms of Breaststrokers Knee

Patients with breaststroker’s knee have pain over the medial joint and increased pain on passive valgus and external rotation of the knee. Activity, especially flexion and external rotation of the knee, makes the pain worse, whereas rest and heat provide some relief. The pain is constant and is characterized as aching; it may interfere with sleep. Patients with injury to the medial collateral ligament may report locking or popping with flexion of the affected knee. Coexistent bursitis, tendinitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee joint.

On physical examination, patients with injury to the medial collateral ligament exhibit tenderness along the course of the ligament from the medial femoral condyle to its tibial insertion and tenderness and over the medial femoral intercondylar ridge and under the medial facet of the patella. If the ligament is avulsed from its bony insertions, tenderness may be localized to the proximal or distal ligament, whereas patients with strain of the ligament have more diffuse tenderness. Patients with severe injury to the ligament may exhibit joint laxity when valgus and varus stress is placed on the affected knee. Because pain may produce muscle guarding, magnetic resonance imaging (MRI) and ultrasound of the knee may be necessary to confirm the clinical impression. Joint effusion and swelling may be present with injury to the medial collateral ligament, but these findings are also suggestive of intra-articular damage. Again, M

How is Breaststrokers Knee diagnosed?

MRI and ultrasound imaging are indicated in all patients with medial collateral ligament pain, particularly if internal derangement or occult mass or tumor is suspected. In addition, MRI should be performed in all patients with injury to the medial collateral ligament who fail to respond to conservative therapy or who exhibit joint instability on clinical examination. Ultrasound imaging may also assess the integrity of the medial collateral ligament. Bone scan may be useful to identify occult stress fractures involving the joint, especially if trauma has occurred. Plane radiographs of the knee may also help identify patellofemoral arthritis, which is commonly seen in more advanced cases of breaststroker’s knee. Based on the patient’s clinical presentation, additional testing, including a complete blood count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be warranted.

RI and ultrasound imaging can confirm the diagnosis.

Differential Diagnosis

Any condition affecting the medial compartment of the knee joint may mimic the pain of breaststroker’s knee. Bursitis, meniscal injuries, arthritis, and entrapment neuropathies may also confuse the diagnosis, as may primary tumors of the knee and spine.

Treatment

Initial treatment of the pain and functional disability associated with injury to the medial collateral ligament includes a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. The local application of heat and cold may also be beneficial. Any repetitive activity that exacerbates the symptoms should be avoided. For patients who do not respond to these treatment modalities and do not have lesions that require surgical repair, injection is a reasonable next step. Ultrasound guidance may help improve the accuracy of needle placement and decrease the incidence of needle-related complication.

Injection of the medial collateral ligament is carried out with the patient in the supine position with a rolled blanket underneath the knee to gently flex the joint. The skin overlying the lateral aspect of the knee joint is prepared with antiseptic solution. A sterile syringe containing 2 mL of 0.25% preservative-free bupivacaine and 40 mg methylprednisolone is attached to a 11⁄2-inch, 25-gauge needle using strict aseptic technique. The most tender portion of the ligament is identified, and the needle is inserted at this point at a 45-degree angle to the skin. The needle is carefully advanced through the skin and subcutaneous tissues into proximity with the medial collateral ligament. If bone is encountered, the needle is withdrawn into the subcutaneous tissues and redirected superiorly. The contents of the syringe are then gently injected. There should be little resistance to injection. If resistance is encountered, the needle is probably in a ligament or tendon and should be advanced or withdrawn slightly until the injection can proceed without significant resistance. The needle is then removed, and a sterile pressure dressing and ice pack are applied to the injection site.

Complications and Pitfalls

The major complication of injection is infection, although this should be exceedingly rare if strict aseptic technique is followed. Approximately 25% of patients report a transient increase in pain after injection of the medial collateral ligament; patients should be warned of this possibility.

Clinical Pearls

Patients with injury to the medial collateral ligament are best examined with the knee in the slightly flexed position. The clinician may want to examine the nonpainful knee first to reduce the patient’s anxiety and ascertain the findings of a normal examination.

The injection technique described is extremely effective in the treatment of pain secondary to breaststroker’s knee. Coexistent bursitis, tendinitis, arthritis, and internal derangement of the knee may contribute to the patient’s pain, necessitating additional treatment with more localized injection of local anesthetic and methylprednisolone.

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