The Assessment and Treatment of Sports-related Acute Knee Injury

Due to the nature of its hinge joint structure and weight-bearing requirement, the knee is easily subject to trauma. This is especially true when it comes to the many stresses that sports and athletics can inflict on the knee.

The supporting structures of the knee include the medial and lateral collateral ligaments, the anterior and posterior cruciate ligaments, surrounding quadriceps, hamstrings, iliotibial band, and pes anserine tendons. The medial and lateral menisci protect the articular cartilage surfaces. Given the complexity of the knee, taking a thorough history of the patient’s injury and symptoms is perhaps the most important part of making the diagnosis (http://1.usa.gov/HI1yXL).

Injury types and testing

Anterior knee pain is associated with patellofemoral injury or subluxation; knee locking occurs with meniscal tears, buckling can occur with loose bodies, meniscal tears, patella pain and quadriceps weakness and instability (http://bit.ly/HVM4Op). Complaints of crackling, clicks, and snapping should be examined to determine what movements cause it.

The anterior cruciate ligament (ACL) originates from the medial aspect of the lateral femoral condyle, twists 90 degrees (adding tensile strength), and inserts onto a tubercle along the anterior tibial plateau. The Lachman test for a possible torn ACL is done with the knee in 30 degrees flexion with the thigh stabilized, exerting a forward motion on the tibia. More than a few millimeters of motion would be abnormal. The pivot shift test is performed by lifting the distal leg, allowing the tibia to fall posteriorly, and adding mild internal rotation and valgus stress. If abnormal, the tibia will sublux further.

The posterior cruciate ligament (PCL) is tested by applying the Lachman maneuver in a posterior direction and feeling for a firm or soft endpoint feel, which might indicate a partial or complete tear.

The medial collateral ligament (MCL) is the most frequently injured knee ligament. It is tested by placing a valgus stress on the knee with the knee in full extension and 30 degrees flexion. No more than a few millimeters movement is normal. The lateral collateral ligament (LCL) is tested through medial stress with the knee extended. Look for the degree of movement and whether it elicits pain.

Patella pain is tested by checking if the Q angle if more than 20 degrees and by doing patella grind and compression tests to try to find a painful facet under the knee cap. The patellar apprehension test is done by cupping your hand above the patella, asking the patient to contract the quadriceps, and looking for sudden pain or hesitancy.

Meniscal injuries are tested by applying careful palpation pressure along the anterior and posterior joint lines and then performing the McMurry test (http://1.usa. gov/He5DVo). Bringing the knee in flexion and providing a valgus stress, then slowly extending the knee, can elicit pain or a click, which indicates a positive test for a meniscal tear. Test the lateral meniscus by performing this maneuver and applying a varus stress.

Tendon injuries are tested by palpating the tendon from its proximal portion to its insertion and doing a resisted isometric test on the tendon looking for pain. Common tendon injuries are in the quadriceps, medial and lateral hamstrings, iliotibial band laterally, and adductors medially at the pes anserine bursa.

Other knee injuries include osteochondral defects in the cartilage, arthritis, and bursitis in the infra or suprapatellar bursa. Evaluation is not complete until you check the feet for pes planus (flat feet) or other deformity, and check leg length, hip range of motion, sensation, muscle strength, and neurological factors.

Treatment

Treatments should be injury specific. In acute stages ice, rest from activity, control excessive swelling, and unload the joint with crutches or cane. Bracing or splinting can be useful if there is instability. Avoid anti-inflammatories, as they may interfere with the necessary stages of healing, which includes a healthy inflammatory response. Early range of motion activities and other light activities are encouraged, which might include physical therapy. Many knee injuries heal naturally in the first eight weeks. If they do not heal, interventional procedures may become necessary. Surgery is a last option unless there is severe instability or a severely torn ligament, fracture, or ruptured tendon. Cortisone injections for simple sprains, strains, or bursitis can be considered, but if the symptoms return, some of the newer methods of treatment using a bioregenerative approach should be considered. Multiple cortisone injections can be harmful to joint cartilage, tendons and soft tissue structures. A torn patellar tendon should never be injected with cortisone. Newer bioregenerative techniques such as PRP (platelet rich plasma), prolotherapy, and stem cell injections that use growth factors in an attempt to repair the injury naturally are also options.

Edward Magaziner, MD, is Medical Director of The Center for Spine Sports Pain Management and Orthopedic Regenerative Medicine (www.dremagaziner.com). He is CEO of the New Jersey Society of Interventional Pain Physicians and President of the NJ PMR Society.