McMurray’s Test Meniscal Tear

McMurray’s test is a commonly used test in orthopaedic examination to test for tears of the meniscus. The McMurray’s test is a rotational maneuver of the knee that is frequently used in the examination of the patient to help in the diagnosis of meniscal tears. Meniscus injuries are very common. When the patient sustains an injury of the knee and has a meniscal tear, usually the patient complains of knee pain localized to the medial or lateral side of the knee. The patient may also have locking and clicking. Sometimes the patient will have an effusion and sometimes this effusion is small (swelling of the knee). Joint line tenderness is the most sensitive finding. Joint line tenderness can be on the medial side (medial meniscal tear) or on the lateral side (lateral meniscal tear). There will be minimal swelling of the knee and possible extension lag (locked knee) due to a displaced bucket handle tear of the meniscus. Pain at a higher level than the joint is usually associated with medial collateral ligament tear. If an MCL tear is present, it is usually avulsed from the medial femoral condyle. The MCL is rarely avulsed from the tibia. Pain at a lower level is usually associated with the pes anserine bursitis. McMurray’s test is a knee examination test that shows pain or a painful click as the knee is brought from flexion to extension with either internal or external rotation of the knee. The McMurray’s test uses the tibia to trap the meniscus between the femoral condyles of the femur and the tibia. When performing the McMurray’s test, the patient should be lying supine with the knee hyperflexed. The examiner then grasps the patient’s heel with one hand and places the other hand over the knee joint. To test the medial meniscus, the knee is fully flexed, and the examiner then passively externally rotates the tibia and places a valgus force. The knee is then extended in order to test the medial meniscus. To test the lateral meniscus, the examiner passively internally rotates the tibia and places a varus force. The knee is then extended in order to test the lateral meniscus. A positive test is indicated by pain, clicking or popping within the knee joint and may signal a tear of either the medial or lateral meniscus when the knee is brought from flexion to extension. There are mixed reviews for the validity of this test. There are other clinical tests that are as good as the McMurray’s test, however MRI is making the diagnosis of a meniscal tear easier. MRI is very sensitive, and it also excludes other associated injuries. I find that the McMurray’s test is valuable in getting insurance approval for performing an MRI. If you state that the McMurray’s test is positive, then the insurance will approve the MRI. Nowadays though, the McMurray’s test does not give us a lot of valuable clinical information, because we get the information from other tests. 

Anatomy of the Trapezius Muscle

 

The trapezius is a large superficial muscle that extends from the back of the skull, back of the neck, and back of the thorax. The upper fibers of the trapezius muscle arise from the external occipital protuberance and the medial third of the superior nuchal line. The middle fibers arise from the ligamentum nuchae and the spinous process of C7. The lower fibers arise from the spinous processes and supraspinous ligaments of all twelve thoracic vertebrae. The trapezius is inserted into the lateral third of the clavicle, and from the acromion process and the spine of the scapula. The trapezius muscle allows for rotation and lift of the scapula. Dysfunction of the trapezius muscle may cause lateral winging of the scapula. Winging can occur after radical neck surgery, but it usually occurs after biopsy or tumor dissection. The spinal accessory nerve will be injured, and the patient will have difficulty with overhead activity. If injury to the spinal accessory nerve occurs early, explore the nerve. If injury is late, do a muscle transfer. The spinal accessory nerve provides motor innervation to the sternocleidomastoid and the trapezius muscle. The spinal accessory nerve courses obliquely across the posterior triangle on the surface of the levator scapula muscle and reaches the trapezius. Within the posterior triangle of the neck, the nerve is vulnerable since it is superficial and only covered by skin and subcutaneous fascia. Extreme caution should be taken for any surgical procedure done in the posterior triangle of the neck.

Neurological Evaluation of the Lumbar Nerve Roots

 

To study the involvement of any nerve root we look for sensory change, motor changes, reflex changes. A herniated disc at T12-L1 affects the L1 nerve root. The sensory of the L1 nerve root is half the distance between the inguinal ligament and mid-thigh. Motor involvement is hip flexion. There are no reflexes of L1. A herniated disc at L1-L2 affects the L2 nerve root. The sensory of the L2 nerve root is mid-anterior thigh. Motor involvement is hip flexion, hip adduction, and knee extension. There are no reflexes of L2. A herniated disc at L2-L3 affects L3 nerve root. The sensory of the L3 nerve root is distal part of the thigh including the knee area. Motor involvement is hip flexion and knee extension. A herniated disc at L3-L4 affects the L4 nerve root. The sensory of the L4 nerve root is medial side of the leg down to the medial side of the foot. Motor involvement is L4 ankle dorsiflexion (tibialis anterior) and knee extension. L4 reflex changes will be a positive femoral stretch test. The test is positive if pain is felt in the ipsilateral anterior thigh. If the test is positive, it means that there is probably a disc herniation between L3-L4, affecting the L4 nerve root. The patellar reflex is mainly L4. A herniated disc at L4-L5 affects the L5 nerve root. The sensory of the L5 nerve root is dorsum of the foot and leg. Motor involvement is hip abduction (gluteus medius) and extension of the big toe. L5 nerve root is very popular in the exam. If you see a big toe extension, this involves the L5 nerve root (L4, L5 disc herniation). The patient may have Trendelenburg gait due to injury to the L5 nerve root (disc herniation between L4, L5 affecting the L5 nerve root). Both the gluteus medius and minimus muscles are innervated by the L5 nerve root. Straight leg raise can be positive with L5 nerve root irritation. This test is used to determine if the patient with low back pain has an underlying herniated disc irritating the nerves. A herniated disc at L5-S1 affects the S1 nerve root. The sensory of S1 nerve root is lateral and plantar aspects of the foot. Motor involvement is S1 hip extension (gluteus maximus), S1 ankle plantar flexion (gastro-soleus), and S1 foot eversion (peroneus longus and peroneus brevis). Positive straight leg raise examination to determine whether patient with low back pain has an underlying component of a herniated disc or not (stretch test). Reflexes are S1 ankle reflex.

Fracture of the Capitellum

 

Fractures of the capitellum are rare and usually occur in the coronal plane and can be difficult to diagnose. Fracture of the capitellum is similar to Hoffa fracture of the distal femur. Both fractures are coronal, difficult to diagnose, and the x-ray may miss the fracture. failure to diagnose this fracture and treat it appropriately can lead to a poor patient outcome. The Bryan and Morrey Classification has four types. Type I is a large fragment of bone and articular cartilage sometimes with trochlear involvement. Type II is a shear fracture of the articular cartilage. The articular cartilage is separated with a small shell of bone. Type III is a comminuted fracture of the capitellum. Type IV is the Mckee Modification; it is a coronal shear fracture that extends medially to include the capitellum and trochlea. You can see double bubble or a double arc on the lateral x-ray of the elbow. One arc represents the capitellum, and the other arc is the lateral ridge of the trochlea. The double arc sign is a pathognomic finding of the capitellar fracture and is usually seen in the lateral elbow x-rays. In more than 50% of the time, capitellum fracture may be associated other injuries such as radial head fracture or lateral ulnar collateral ligament injury. Fracture of the capitellum can cause mechanical block to movement of the elbow. The fracture can be seen on the lateral x-ray of the elbow, however CT scan is helpful in showing the fracture adequately. Nonoperative treatment for nondisplaced fracture is to give the patient a splint for less than 3 weeks followed by range of motion. Open reduction internal fixation is done for displaced fractures. We rarely excise the capitellum, but you may get into this situation if the fragment is displaced and causing symptoms and if most of the fragment is cartilage attached to a thin piece of bone and the fragment could not be fixed. You will try to fix it first before you excise it. Excision is done for Type III fractures, for comminuted and displaced fractures, especially if there is a block to movement of the elbow. Small displaced, insignificant fractures can be excised if it is causing pain or mechanical block to elbow motion. Excision of a large fragment of the capitellum can create a problem of developing arthritis or instability, especially if the medial collateral ligament is injured. Do total elbow arthroplasty when there is a comminuted fracture of the capitellum that extends to the medial column and the fracture is unreconstructable and the patient is old. For open reduction internal fixation, the ideal visualization of the fracture is usually provided by a lateral approach (Kaplan or Kocher approach). The patient is usually in the supine position. Elevate the common extensor tendons and the capsul anteriorly off the lateral column and use headless compression screws from anteriorly to posteriorly. The fracture is partial articular and vertical shear. Going anteriorly to posteriorly will allow excellent compression and stability of the fracture. Countersink the screws. Bury the screw heads beneath the articular cartilage anteriorly. Try to avoid destabilizing the lateral ulnar collateral ligament and try to make the dissection more anterior to the equator of the radial head. Try to avoid disruption of the capitellum blood supply that comes from the posterolateral area. Stay anteriorly to avoid these two problems. A complication of capitellar fractures is elbow stiffness. Surgery to fix the capitellar fracture will help in gaining the functional range of motion, but the patient will have residual stiffness. Surgery is probably better than no surgery, but the reoperation rate is high due to the residual stiffness of the elbow.