Olecranon Fractures

Fractures of the olecranon may occur due to a direct blow to the elbow or from a fall onto an outstretched hand. Nondisplaced fractures have less than 2mm of separation and are considered stable. Fracture separation will not increase with elbow flexion. Extensor mechanism is intact and the patient will be able to extend the elbow against gravity. Displaced fractures could be an avulsion, oblique, transverse, comminuted, or dislocated.

Olecranon fracture dislocations can be anterior (transolecranon) or posterior (similar to monteggia fracture dislocation). An examination will show that the patient is unable to extend the elbow with these displaced fracture types. A true lateral view x-ray will clearly show the olecranon fracture. Usually, these fractures are followed by stiffness of the elbow in about 50% of the patients. However, this does not affect the function.

The goal of treatment for olecranon fractures should be restoration of the articular surface, preservation of the continuity of extensor mechanisms, maintain elbow stability, and avoid stiffness of the elbow. Nonoperative treatment is used for nondisplaced fractures and it may be used for some displaced fractures in elderly patients (treat elbow in some flexion with a splint). I would personally use minimally invasive techniques in these patients unless the skin is very bad, or the fracture is very comminuted.

There are three techniques used for surgical treatment: the tension band technique, detach olecranon and reattach triceps, and plate and screw fixation. The tension band technique is only used for transverse fractures with no comminution. K-wires and screws are used, and the surgeon may use either a 6.5mm screw or Kwires for the tension band. When doing the tension band technique, you want to engage the anterior cortex of the ulna. The surgeon should avoid over penetration to avoid affecting the forearm rotation or injuring the anterior interosseous nerve. The surgeon needs to be sure that the pins are not fixing the radius and that after the operation, the patient can perform pronation and supination of the forearm (pull the pins out slightly if needed). The distractive force of the triceps is converted to compression force at the articular surgace, especially when bending the elbow. The drill hole for the K-wire should be positioned about 4-5cm from the fracture which gives enough safe distance so that the fracture will not propagate. Place the tension band wire through the drilled holes before application of the K wires. The surgeon should be sure that the hook to the K-wire is posterior. Make sure that the tension band wire is close to the bone so there is no laxity in the fixation and instability. An intramedullary screw could be used. This screw fixation may need a washer to capture the tension band wire. Intramedullary 6.5mm screw fixation is a reasonable option for fixation but it may need to be supplemented with tension band wires. Never use cancellous screw alone. The tension band technique are for transverse fractures of the olecranon. If fractures comminution is present, change the plan of fixation.

When detaching the olecranon and reattaching the triceps, an excision of the fracture fragment and triceps advancement is used:

• If the fracture is less than 50%
• To treat elderly patients (especially if fracture is comminuted)
• For some nonunions when the fracture is small and cannot be fixed

The surgeon must be sure that the procedure is done with the elbow is stable. If the elbow has ligamentous instability and excision of the fracture fragment is done, this will make the elbow very unstable. The triceps should be attached closer to the articular surface.

Special olecranon plates are available when using a plate and screw fixation technique. The bridge plate and screw fixation technique is used in comminuted, Monteggia, oblique fractures extending to the coranoid, and fracture dislocation. The plate is placed on the tension side of the olecranon (dorsal side). Sometimes, an opening is made through the triceps and the plate is placed against the bone, then suturing the triceps tendon over the plate to avoid hardware prominence.

In summary, if the patient is elderly with a small, comminuted fracture fragment less than 50% of the joint space, excise the fragment, and reattach the triceps tendon to the olecranon. If the olecranon fracture is transverse and proximal to the base of the coranoid process, then use the tension band technique. Use plate fixation for all olecranon fracture scenerios, such comminuted fractures, oblique fractures, unstable fractures, dislocation, or fractures distal to the coranoid process. The typical exam question scenario will discuss a comminuted fracture that should be treated with a plate. You probably need to remove above 20% of the plate fixations due to hardware irritation. Hardware irritation is worse with the tension band surgical treatment (may need to remove in more than 50% of cases).

Knee Jerk Reflex

The knee jerk reflex or patellar reflex, is a deep tendon reflex seen as a sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon. Tapping the patellar ligament stimulates the muscle spindles in the quadriceps. Impulses travel from the muscle spindles to the spinal cord. In the spinal cord, synapses occur with motor neurons and interneurons. The motor (efferent) neurons send activating impulses to the quadriceps causing the muscles to contract and extend the knee. The interneuron (relay neuron) forms a connection between the other neurons and interneurons. Interneurons are neither motor nor sensory. Interneurons transmit impulses that inhibit the antagonistic muscles (hamstrings). An abnormality of the reaction suggests that there may be damage to the central nervous system.

Anterior Interosseous Nerve- The Benedictine and O.K. Sign

A patient with a complete anterior interosseous nerve injury or a high medial nerve injury should be asked to make a fist. The first and second digits will have difficulty in flexing, while the other digits will flex. The third digit will be weak, while the fourth and fifth digits are normal. This position of the hand is similar to the position taken during a hand blessing. The Benedictine sign is different from an “ulnar claw hand”. Ulnar claw hand refers to damage to the ULNAR nerve and is seen when attempting to extend all the digits (leaving the 4^th and 5^th digits flexed). The O.K. sign is used to check for paralysis of the anterior interosseous nerve due to entrapment or compression injury. A patient with paralysis of the anterior interosseous nerve will be unable to make the O.K. sign. This is due to weakness of the flexor pollicis longus and flexor digitorum profundus muscles. A typical pinch attitude is associated with anterior interosseous nerve injury.

The anterior interosseous nerve arises from the median nerve about 4-6cm distal to the elbow, which is about 1/3 of the way down the forearm. It exits from the anterolateral aspect of the median nerve and it runs between the radius and the ulna on the interosseous membrane between and below the muscles of the flexor digitorum profundus and the flexor pollicis longus.

The anterior interosseous nerve supplies the flexor digitorum profundus muscle for the index and long fingers. It also supplies the flexor pollicis longus and the pronator quadratus muscles. The flexor digitorum profundus muscle for the index and long fingers is supplied by the anterior interosseous nerve. The medial part of the FDP is supplied by the ulnar nerve (FDP has dual innervation). The anterior interosseous nerve passes dorsal to the pronator quadratus with the anterior interosseous artery and provides innervation to the volar wrist capsule. The terminal branch of the anterior interosseous nerve innervates the carpal joint capsule.

In patients with Martin-Gruber Connection, the median nerve, or anterior interosseous nerve to the ulnar nerve in the forearm may present with intrinsic muscle weakness. It may be differentiated also from Parsonage-Turner Synrome (acute brachial plexus neuritis) and patient may have pain in the affected extremity. In anterior interosseous nerve entrapment, the median nerve conduction study result will be normal, however the needle EMG of the anterior interosseous innervated muscles will be abnormal.

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.