Tests Orthopaedic Surgeons Should Think About

There are some important tests that every Orthopaedic Surgeon should think about. This doesn’t mean the tests are needed for every patient. It just means that the physician needs to think about these tests to see if it will benefit the patient or not. Some tests commonly ordered are hemoglobin A1C (HbA1c), Vitamin D25, and C-reactive protein (CRP) & sedimentation rate.

Hemoglobin A1C test are ordered for diabetic patients. HbA1c is a good test for monitoring long-term glucose (sugar) control on patients with diabetes. HbA1c is a percentage of the glycanated hemoglobin relative to the total hemoglobin in the blood. The normal range of HbA1c is 4-6%. More than 7% is high. Another test, the 25-Hydroxy Vitamin D blood test is ordered for patients with osteoporosis, nonunions, fragility fractures, and occasionally in patients with infections. If infection is suspected and the physician needs to monitor the progress of treatment, C-reactive protein (CRP) & sedimentation rate tests should be ordered. A Methicillin-resistant staphylococcus aureus (MRSA) screening should be ordered for patients who could be carriers. Nutritional assessments may be necessary for other patients.

Joints should be aspirated prior to injecting of the joint. The physician should additionally be sure that there is no infection when injecting the joint. A fluid analysis from the joint should be completed. Important vascular studies that can be ordered include: A.B.I., CTA, or a Doppler. Some radiological studies are performed with a dye injection. For example, an MRI of the spine will require gadolinium, while an MRI arthrogram may be used for the hip or shoulder. Tests rarely ordered include: alpha-defensin test (infection); Nicotine/Cotinine test (smoking); Protein S, Protein C, or Factor 5 leiden tests. There are some special tests and precautions that must be taken for patients with epilepsy. It is important that the physician does not perform a procedure if the epilepsy is not controlled. It is important to know that anti-epileptic medication can interfere with vitamin D metabolism in the liver.

Patients on anticoagulation medications should be monitored, especially patients with atrial fibrillation, which makes the orthopaedic procedure more complicated. You want to give the patient anticoagulation, but not encroaching on the management of atrial fibrillation. Patients with a short or thick neck, or a history of sleep apnea, may need additional sleep studies before surgery and may need special precautions after surgery. Sleep apnea will affect the post-operative care of the patient. The physician should avoid ordering unnecessary tests and focus on ordering the most important tests. Orthopaedics deal with concepts and every condition will have a reasonable way of diagnosing it and a reasonable way of treating it.  

McMurray's Test- Meniscal Tear

Meniscal injuries are very common. The McMurray’s Test is a rotational maneuver of the knee that is frequently used to aid in the diagnosis of meniscal tears. With a meniscal tear, the patient usually complains of knee pain localized to the lateral or medial side of the knee joint. The patient will have locking, clicking, pain, or effusion.

During the physical examination, joint line tenderness is the most sensitive finding. Swelling of the knee and a possible extension lag (locked knee) is also a common finding. Pain at a higher level is usually associated with the medial collateral ligament. Pain at a lower level is usually associated with the pes anserine bursa.

What is the McMurrays test?             

The McMurray’s test is a knee examination test that provokes pain or a painful click as the knee is brought from flexion to extension with either internal or external rotation. The McMurray’s test uses the tibia to trap the meniscus between the femoral condyles of the femur and the tibia. When performing the 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 joint and may signal a tear of either the medial or lateral meniscus when the knee is brought from flexion to extension.

How reliable is the McMurray’s test?

There are mixed reviews for the validity of this test. An MRI is a very sensitive exam and makes the diagnosis easier, while excluding other associated injuries.

Pivot Shift of the Knee—ACL tear

The anterior cruciate ligament is located at the front of the knee. Rupture of the anterior cruciate ligament (ACL) is a condition commonly seen in sports, usually due to a non-contact pivoting injury. The Pivot Shift test is a specific test for an ACL deficient knee (ACL injury). A pivot shift is pathognomonic for an ACL tear and is best demonstrated in a chronic setting. The Lachman’s test is the most sensitive examination test for an ACL injury.

The ACL keeps the tibia from sliding out in front of the femur and provides rotational stability to the knee. Rupture of the ACL causes anterolateral rotatory instability. The tibia moves anterolaterally in extension; however, when you flex the knee the IT band becomes a flexor of the knee and pulls back, reducing the tibia. The Pivot Shift Test goes from extension (tibia subluxed) to flexion, with the tibia reduced by the iliotibial band.

Both the Lachman’s test and the Pivot Shift test are associated with 20-30 degrees of knee flexion. The Lachman’s test starts at 20-30 degrees of flexion, but with the Pivot Shift test, you will feel the clunk at 20-30 degrees of flexion. Remember: 20-30 degrees of flexion is important for examination of the ACL. The femur is stabilized with one hand and the other hand pulls the tibia anteriorly and posteriorly against the femur. The tibia can be pulled forward more than normal (anterior translation). The examiner will have a sense of increased movement and lack of a solid end point.

When performing the Pivot Shift test, the patient should be totally relaxed and lying supine. The knee is in the subluxed position when in full extension. The pivot shift starts with extension of the knee and you can feel a “clunk” at 20-30 degrees of flexion. The physician will hold the knee in full extension, then add valgus force, and internal rotation of the tibia to increase the rotational instability of the knee. Then the physician will take the knee into flexion. A palpable clunk is very specific of an ACL tear. The iliotibial band will reduce the tibia and create the clunk on the outside of the knee. The physician should always compare the results with the other side.

The ACL prevents anterior translation of the tibia. It is a secondary restraint to tibial rotation and varus and valgus. The ACL consists of two bundles:

• The Posterolateral Bundle
• Anteromedial Bundle

The Posterolateral bundle prevents the pivot shift and contributes to rotational stability. This bundle also prevents internal rotation of the tibia with the knee in near extension (tight in extension, loose in flexion). If it is sectioned, it increases the anterior translation and tibial rotation at 30° of flexion. The Anteromedial bundle is tight in flexion and if sectioned, it increases the anterior translation at 90° of flexion.

The Lachman’s test is the most sensitive test, especially in acute settings. The examiner will find no end point with anterior translation of the knee and the physical examination can be difficult or limited due to pain. With the Pivot Shift test, the patient must be completely relaxed. The test is helpful in chronic situations, especially if the patient complains of the knee giving way.

During the Pivot Shift, the knee subluxes in extension and reduces at 20-30 degrees of flexion. The Pivot Shift correlates closely with patient satisfaction of their reconstructed knee. It is also a measure of functional instability following ACL reconstruction. Verticle femoral tunnel placement will cause rotational instability seen as a positive pivot shift, and the malposition of the bone tunnel will be seen in an AP view x-ray of the knee. The 9 or 10 o’clock position is better than the 12 o’clock. A vertical position is bad.

The patient with an ACL injury usually has a non-contact pivoting injury even with:

• Awkward landing
• Feeling a “Pop” sensation
• Immediate swelling
• Aspiration usually shows blood in the knee (75% chance of ACL tear with hemorrhage in the knee)
• Positive Lachman’s Test (may be hard to examine due to pain)

An MRI is going to be the best imaging technique. An MRI of the knee joint will show bone lesions or bruising in the typical location associated with tears of the ACL. These injuries are typically located at the middle of the femoral condyle and posterior part of the tibia laterally. It is also possible to find a triple injury within the MRI (O’Donoghue’s Unhappy Triad).

O’Donoghue’s Unhappy Triad consists of:

1. Tear of the Lateral Meniscus
2. Anterior Cruciate Ligament Injury (ACL tear)
3. Medial Collateral Ligament Injury

In chronic ACL tears, the posterior horn of the medial meniscus is the most commonly injured structure. In acute ACL tears, send the patient for therapy for range of motion, brace the patient, and allow the MCL to heal and reconstruct the ACL later if needed. It is important to stress hamstring therapy in ACL tears. The patient will probably complain of instability immediately or later on.

Barlow & Ortolani Signs—DDH, Congenital Hip Dislocation

In order to remember these tests, remember that “B” comes before “O” in the alphabet and will go in this order for these procedures as well. The “B” stands for Barlow and “O” for Ortolani. When reading the word “barlow” think: “We are going out tonight!”, because the hip can be popped out of the acetabulum with this maneuver. To remember Ortolani, think: “Once we have been out, now it is time to go home!”—during the Ortolani maneuver, the femoral head is reduced back into the acetabulum.

The Barlow maneuver identifies the unstable hip that is in a reduced position that the clinician can passively dislocate. When performing the Barlow Test, the examiner will flex the hip and knees to 90 degrees. The maneuver is performed by bringing the thigh towards the midline (adducting the hip). Mild pressure is then placed on the knee while directing the force posteriorly. The femoral head will be pushed out of the socket. The Barlow Test is considered positive if the hip can be popped out of socket with this maneuver. The dislocation will be palpable.

The Ortolani Test is used to confirm the findings of the Barlow test. The Ortolani maneuver is performed following the Barlow test to determine if the hip is actually dislocated. The Ortolani test is performed by the examiner flexing the hips and knees to 90 degrees. Reduction is done by abduction of the hip and pushing the thigh anteriorly. The test is positive is a palpable and audible clunk is heard from the hip being reduced. A hip click is a nonspecific finding.

In summary, The Barlow Test is performed when the hip is reduced and is used to dislocate the hip. The Ortolani Test is performed only after the Barlow Test has been performed and the hip has been dislocated. The Ortolani Test will reduce the hip.

Both of these tests are used for screening newborns during the neonatal period. The hips are examined one at a time and usually the hips are flexed during these maneuvers. Early diagnosis by these tests and preferably with ultrasound is essential to detect hip instability and dislocation in the neonatal period.

Treatment is directed at stabilizing the hip that has positive Barlow and Ortolani Signs. The first born female with a breach presentation and a positive family history are at risk of developing developmental dysplasia of the hip (DDH). If the hip remains dislocated for weeks, these two tests are usually not reliable. Barlow and Ortolani are not positive after 3 months due to the soft tissue contracture around the hip region. Limitation of abduction becomes the most consistent clinical findings. Children older than 12 months will have other findings which include asymmetry of hip abduction, a positive Trendelenburg gait and a positive Galeazzi sign.

Bulbocavernosus Reflex and Spinal Shock

The bulbocavernosus reflex indicates the absence or presence of spinal shock. Spinal shock usually occurs between 24-72 hours after a spinal injury. Spinal shock is manifested by the absence of the bulbocavernosus reflex, hypotension, bradycardia, and complete loss of motor sensation and reflexes. When the reflex is absent, this means that the patient is in spinal shock because the anal sphincter will not contract when the reflex is absent.

When the reflex is present, this signals the end of spinal shock; the anal sphincter will contract when the reflex is present. The reflex is check by monitoring anal sphincter contraction in response to squeezing of the penis of clitoris, or by pulling on an indwelling Foley catheter. It is a polysynaptic response mediated by S2-S4.

What is Spinal Shock?

Spinal shock is the loss of sensation and motor power following a spinal cord injury. Spinal shock is the loss of sensation and motor power following a spinal cord injury. After an injury to the spine, if the patient has no motor or sensory below the level of the lesion, the physician must determine if the patient is in spinal shock by checking the bulbocavernosus reflex.

If there is no anal contraction (absent bulbocavernosus reflex), this indicates that the patient is still in shock and the prognosis cannot be determined. If anal contraction is present (positive bulbocavernosis reflex), this indicates the end of spinal shock. The patient’s condition and prognosis at this point can be determined by examining sacral sparing (positive sacral sparing indicates an incomplete lesion).

Loss of sensation and motor power below the level of injury indicates complete spinal cord injury. Once the diagnosis of neurogenic shock is established, the blood pressure should be managed with vasopressors to prevent fluid overload. With the end of spinal shock, the prognosis can be determined. Examine the patient thoroughly, including sacral sparing. The patient may have normal, partial, or complete indications. 

Gout, Arthritis and Joint Pain

The most common joint affected by gout is the 1^st metatarsophalangeal joint. The most common joint affected by pesudogout is the knee joint (Figure 1). Gout and pseudogout are similar problems with different causes.

Gout is caused by the buildup of uric acid and the deposit of uric acid crystals inside a joint. The best test to diagnose gout is with a joint fluid analysis. Elevated uric acid is not a good criteria. 90% of patients suffering from gout are men between the ages of 40-60 years. Gout crystals are needle shaped and negatively birefringent. When placed under polarized light they will be yellow (Figure 2).

Uric acid builds up the body by two main mechanisms. These two mechanisms are excessive urate production and diminished urate clearance. Uric acid is produced from the breakdown of proteins inside the body and from the proteins of food that is eaten.

Precipitating Factors:

The sudden attack of gout can be brought on by anything that increases the level of uric acid in the blood such as dehydration, increased consumption of alcohol, eating large amount of meat or seafood, and trauma/surgery.

Diagnostic Testing:

Aspiration and analysis of the joint fluid is the best method for diagnosis (Figure 3). There are blood tests such as white blood cell count, C-reactive protein, erythrocyte sedimentation rate, and uric acid level that are helpful in supporting the diagnosis if elevated, but if normal, it cannot definitively rule out gout or pseudogout.

Pesudogout or chondrocalcinosis is the deposition of calcium pyrophosphate dehydrate crystals in the hyaline cartilage or fibrocartilage (CPPD). Pseudogout is a metabolic disease where calcium pyrophosphate dehydrate crystals (CPPD) are formed within the joint space. It most often affects the knee and occurs more in older patients. It is a calcification of fibrocartilage (chondrocalcinosis). Pseudogout crystals are rhomboid shaped and positively birefringent. Crystals will be blue when placed under polarized light (Figure 4). Associated conditions are hyperparathyroidism, rheumatoid arthritis and gout.

Gout and pseudogout both show a sudden onset of pain, redness and swelling typically affecting a single joint in 80% of the cases. Gout symptoms include joint pain, swelling and arthritis. Patients with gout have periarticular erosions along with the formation of uric acid soft tissue masses in and around the joint which can be seen on x-ray. Soft tissue tophus deposition with periarticular erosions called “punch-out” lesions (Figure 5).

X-rays in pseudogout will show this calcification in the articular cartilage or menisci, with involvement of the patellofemoral joint (Figure 6). Calcifications of the synovium, tendon, and ligaments can also be seen.

Treatment of Gout and Pseudogout:

Acute gout can be treated with indocine and colchicine (be aware of peptic ulcer). In cases of chronic gout the patient will be treated with allopurinol (xanthine oxidase inhibitor) and colchicine. Uricosuric drugs such as Probenecid may increase uric acid excretion by the kidneys may be helpful. Pseudogout is treated with NSAIDs and intra-articular injections.

Congenital Muscular Torticollis

Congenital Muscular Torticollis is usually caused by contracture of the sternocleidomastoid muscle and usually occurs in infants. The cause of congenital muscular torticollis is unknown. It may be caused form pressure on the muscle or compartment syndrome of the muscle. The child holds the head towards the affected side with the chin rotated towards the opposite side. There is difficulty in turning the head due to a tight and shortened sternocleidomastoid muscle. It is a common neck problem in childhood and the condition usually resolves itself spontaneously over a period of several months.

Conditions associated with congenital muscle torticollis:

Molding disorder or packaging deformity such as hip dysplasia (DDH) and metatarsus adductus (up to 20%). Usually delivery is traumatic and probably breach.

Child will have a frim palpable mass within the first four weeks of life and a head tilt.

X-rays of the cervical spine are needed to exclude other conditions such as rotatory C1-C2 instability and Klippel Feil syndrome.

Ultrasound is important as it can differentiate between mild cases and severe fibrosis.

Differential diagnosis of Congenital Muscular Torticollis:

Rotatory Atlanto-axial instability/ Grisel’s disease and Klippel Feil syndrome. These conditions are serious.

Congenital Muscular Torticollis usually resolves spontaneously in about 90% of infants by passive stretching in the first year. Passive stretching technique should include lateral head tilt away from the affected side and chin rotation towards the affected side.

Treatment may be guided by the findings in ultrasound examination of the muscle. Surgical treatment by Z plasty is done if the child is older than 1 year with severe limitation or rotation.