elbow

Figure 11.1

The elbow: posterior and medial views

Introduction

The elbow joint (or elbow complex) is a more complex joint than most people believe. It plays an extremely important part in dynamic movements of the upper extremity such as reaching, lifting and the orientation of the hand, and loss of mobility through the elbow can have a huge impact on quality of life and independency (Turpin et al 2012).

Common injuries in the elbow are associated with overstrain and repetitive movements, resulting in tendinopathies or epicondylitis. The etiology of this can be from occupational stresses as well as recreational or sporting, but lateral epicondylitis is commonly called ‘tennis elbow’ (or ‘lawn tennis arm’ – Morris 1882) and medial epicondylitis is commonly classified as ‘golfer’s elbow’. Lateral epicondylitis is one of the most common upper extremity complaints and it has an estimated occurrence of 0.7–4.0% in the population (Coombes et al 2009, Shiri & Viikari-Juntura 2011). It affects the dominant upper extremity predominantly (Shiri et al 2006, Smidt et al 2006). A study by Silverstein et al (1998) found that 11.7% of work-associated injury claims in Washington between 1987 and 1995 were related to either lateral or medial epicondylitis. These resulted in an average compensation of $6593 per case. Walker-Bone et al (2012) reported that 5% of the participants in their study had taken sickness absence due to epicondylitis, and they took an average of 29 days’ absence in a year due to their symptoms.

Many researchers have investigated the occupational epidemiology of epicondylitis, which shows higher rates of occurrence in occupations involving manual tasks (Walker-Bone et al 2003, Shiri et al 2006, Fan et al 2009, van Rijn et al 2009). An interesting occupation that has a high incidence is the meat-handling trade; this is possibly due to the repetitive movements involved in sausage making, packing and the cutting of the meat (Kurppa et al 1991, Shiri & Viikari-Juntura 2011, Walker-Bone et al 2012). The US National Institute for Occupational Safety and Health (NIOSH) recognizes a strong link between occupations that involve a combination of factors such as force, repetition and vibration and the risk of developing epicondylitis, but limited evidence is found when looking at these factors individually (Bernard 1997). In the United Kingdom, the Health and Safety Executive (HSE) defines epicondylitis as pain and tenderness over the epicondylar (lateral or medial) region and pain with resisted flexion of the wrist for medial epicondylitis and resisted extension for lateral epicondylitis (Harrington et al 1998). Work by Schaefer and Speier (2012) found studies that recorded incidences of musculoskeletal disorders of the elbow in musicians between 56.8% and 77%, mainly in string musicians. Other studies into epicondylitis have found a possible predisposition in females compared to males, although this is still unclear (Shiri et al 2006), and possible links with obesity (Werner et al 2005). Studies have demonstrated that articulation of the elbow joint/complex can be beneficial in hypoalgesia and improving the symptoms associated with epicondylitis (Abbott et al 2001, Paungmali et al 2003, Vicenzino 2003, Vicenzino et al 2007).

Distal and partial ruptures of the biceps brachii also affect the elbow, as does tendinitis of the distal biceps, although these are less common than epicondylitis. They typically affect the dominant arm and are most common in men between 40 and 50 years of age. Factors that are associated with these include smoking (smokers are 7.5 times more likely to suffer than non-smokers), previous injury and use of anabolic steroids (Taylor & Hannafin 2012).

Anatomy

The elbow joint is a large, complex structure. Although it appears to be a much simpler joint than the shoulder, it is one of the most intricately constructed joints in the body. In fact, it is a complex hinge between three bones: the humerus in the upper arm, and the ulna and radius in the forearm. These bones are attached by various ligaments and tendons and are influenced by a number of muscles that cross the joint (Alcid et al 2004). The elbow is one of the most highly congruent and stable joints in the body. Anteriorly, it is constrained by the radial head and coronoid process; posteriorly, it is protected by the olecranon, the bony eminence at the very tip of the elbow (Bain 1999). A single fibrous capsule encloses the entire joint complex, which is strengthened by both the medial and lateral ligaments (Morrey et al 1981).

The elbow joint consists of three separate articulations: the humeroulnar joint, the humeroradial joint and the superior radioulnar joint. These three joints comprise a single compound joint and work in coordination to allow flexion and extension of the upper limb and, at the same time, supination and pronation of the forearm and wrist (Villaseñor-Ovies et al 2012) (see Table 11.1).

The average carrying angle of the elbow is 10–15° in males and is about 5° greater in females (An et al 2009). Sharma et al (2013) found in their study and other research that the carrying angle increases in both males and females during puberty and also that it is greater in the non-dominant extremity. There have been many theories as to the cause of variation in the carrying angle, including the shape and position of the inner (medial) lip or edge of the trochlea, the angle of the trochlear groove, curvature of the shaft of the ulna, the coronoid process or the olecranon (Purkait & Chandra 2004, Kumar et al 2010), but none of these has been statistically proven to be the main determinant of the angle.

Movement type	Range of motion (°)
Flexion	150
Extension	Males: 0 Females: 10–15
Pronation and supination	80–90

Table 11.1
Range of motion of the elbow complex

The elbow joint acts as the mechanical link in the upper limb between the shoulder and the hand. This interconnection provides the arm with much of its versatility and allows the hand to move toward and away from the body. The major functions of the elbow are placing the hand in space, serving as a hinge or support for the forearm, allowing sturdy grasping, and affording fine movements of the hand and wrist. Injury of the elbow joint can result in significant disability and upset activities of daily living and job-related tasks. A sound understanding of the anatomy and biomechanics of the elbow is therefore essential for physiotherapists, surgeons and researchers, among others (Fornalski et al 2003).

Bony anatomy

Humerus

The distal humerus contributes two humeral condyles – the capitellum laterally and the trochlea medially – to the articular surfaces of the elbow joint. The humeral condyle is a round prominence that is covered in articular cartilage, a tube-like structure that covers most of the distal end space of the humerus (An & Morrey 2000). On the lateral aspect of the humeral condyle are the medial and lateral epicondyles. The medial epicondyle protects the ulnar nerve and is more prominent than the lateral epicondyle. It gives attachment to the ulnar collateral ligament and flexor–pronator group. The less prominent lateral epicondyle is the region where the radial collateral ligament and extensor–supinator group are attached. Anteriorly, the radial fossa (superior to the capitulum) and the coronoid fossa (superior to the trochlea) accommodate the head of the radius and the coronoid process of the ulna, respectively, when in full flexion. Posteriorly, the olecranon fossa accommodates the olecranon process of the ulna in full extension (Celli 2008).

Ulna

The ulna is prismatic in shape and is the larger of the two long bones (ulna and radius) in the forearm. It articulates with both the humerus and the radius. The ulna proximally contributes the articulation of the elbow with an intrinsic stability, particularly in full extension. It provides the articular cartilage-covered trochlear notch to the hinge of the elbow joint and articulates with the trochlea of the humerus as a hinge joint. It articulates with the radius near the elbow as a pivot joint. The ulna includes the olecranon (the bony process where triceps muscle tendon attaches) and the coronoid process (a triangular eminence where the brachialis attaches) (Fornalski et al 2003).

Articulation	From	To	Joint type	Motion
Humeroulnar joint	Trochlear notch of the ulna	Trochlea of humeral condyle	Synovial hinge joint	Flexion and extension
Humeroradial joint	Superior aspect of the radial head	Capitulum of the humeral condyle	Combined hinge and pivot joint	Flexion and extension as well as rotation of the radial head on the capitellum
Superior radioulnar joint	Radial head	Radial notch of the ulna	Pivot-type synovial joint	Pronation or supination movement

Table 11.2
Articulations of the elbow joint

Data from Kuxhaus (2008), Fornalski et al (2003)

Radius

The radius is a prism-shaped long bone, which runs parallel to the ulna and extends from the elbow’s lateral part to the thumb side of the wrist. It includes the head of the radius or radial head, which articulates with both the capitellum of the humerus and the radial notch of the ulna. Distal to the radial head is a narrowing of the bone, known as the radial neck. Medial to the radius, and just distal to the radial neck, is an oval projection, referred to as the radial tuberosity, which receives the biceps tendon (An & Morrey 2000).

Joint articulations

The articulations of the elbow joint are summarized in Table 11.2.

Ligaments

The ligamentous complexes reinforce osseous stability and serve as stabilizers for the elbow joint. The triangular medial (or ulnar) collateral ligament is formed by the medial capsular thickenings. It extends from the medial humeral epicondyle to the olecranon and coronoid process of the ulna. The medial complex contributes valgus stability to the flexed elbow (Morrey et al 1991) and comprises three components: the anterior, posterior and transverse bundles. The anterior bundle gives the highest elbow stability, the posterior bundle inhibits pronation of the ulna in cooperation with the bony articulations, and the transverse bundle helps to extend the trochlear notch (Jackson & McKeag 1997).

The lateral (or radial) collateral ligament is formed by the lateral capsular thickenings. It originates from the lateral epicondyle of the humerus and distally blends with the annular ligament of the radius. The radial collateral ligament supports the annular ligament during varus stress (Chumbley et al 2000) and helps stabilize the lateral humeroulnar joint, precisely by inhibiting supination of the ulna (Bain 1999).

Epidemiology

Elbow injuries

The elbow is the most common site of injury in athletes of all ages and skill levels, especially in sports involving overhead arm motions, such as throwing and racquet sports. Playing such sports involves considerable compression forces on the lateral radiocapitellar joint and tension forces on the medial side of the elbow, leading to a range of pathological conditions (Whiteside et al 1999).

Condition	Description	Reference
Lateral epicondylitis (tennis elbow)	A condition in which the lateral epicondyle of the humerus becomes sore and tender Involves an acute or chronic inflammation of the tendons Results from overuse of the wrist extensor musculature, such as extensor carpi radialis brevis Occurs in more than 50% of athletes that use overhead arm motions Annual incidence: 4–7 cases per 1000 patients Peak incidence: 40–50 years of age	Field & Savoie (1998), Smidt & van der Windt (2006), Johnson et al (2007)
Medial epicondylitis (golfer’s elbow)	An inflammatory condition of the tendons Characterized by pain and repetitive stress at the flexorpronator tendinous origin with pathology Results from repetitive valgus stress, flexion and pronation placed on the soft tissues of the medial elbow Causes tendinosis of the medial epicondyle of the humerus Most commonly affects men aged 20–49 years Peak incidence: third to fourth decades of life	Chumbley et al (2000), Gabel & Morrey (2000), Johnson et al (2007)
Dislocation of the radial head (pulled elbow)	Often comes with significant trauma Occurs when the radial head is pulled out of the annular ligament Results in displacement of radial head from its normal articulation with the humerus and the ulna In children, the head of the radius is more frequently subluxed than dislocated Occurs most commonly in male adults who are subject to high-force injury Peak incidence occurs in young children (under the age of 5), more frequently in girls	Ovesen et al (1990), Tosun et al (2008)
Olecranon bursitis (student’s elbow)	An inflammation of the olecranon bursa, which is located just above the extensor aspect of the proximal end of the ulna Characterized by pain, swelling and redness near the olecranon process Usually develops as a result of prolonged pressure, single injury to the elbow, mild but repeated minor injuries, infection, trauma or other condition that aggravates inflammation Peak incidence occurs at older age	Snider (1997), Brinker & Miller (1999)
Pronator teres syndrome	A proximal median neuropathy of the forearm Causes paresthesia in the distribution of the median nerve Incidence: very rare and limited	Hartz et al (1981), Lee et al (2014a)
Radial tunnel syndrome	Classic feature is pain over the radial proximal forearm with little or no motor weakness Pain is centered over the lateral epicondyle (sometimes making differential diagnosis with lateral epicondylitis difficult)	Charalambous & Stanley (2008), Huisstede et al (2008)
Cubital tunnel syndrome	Second most common nerve entrapment (carpal tunnel syndrome is first) Is a consequence of compression of the ulnar nerve, resulting in pain or paresthesia in the fourth and fifth digit and pain on the medial side of the elbow Manual workers are most prone	Bartels et al (2005), van Rijn et al (2009)

Table 11.3
Common pathological conditions of the elbow

Elbow injuries may occur at any of the functional structures in the region. However, the frequency of elbow pain and the type of injury vary greatly, depending on the type of athletic pursuit and, in some sports, on the athlete’s position. Injuries to the elbow, wrist and forearm are responsible for roughly 25% of all injuries related to sports (Amadio 1990).

The majority of sporting elbow injuries are classified as either traumatic or overuse (Dugas & Cain Jr 2005). Azar et al (2000) found that ulnar collateral ligament (UCL) reconstruction had increased 50% from 1995 to the time of their study. Elbow injuries are particularly common in sports involving throwing, such as baseball (Fleisig et al 2011, Tyler et al 2014) and javelin (Dines et al 2012, Leigh et al 2013). In their review of elbow injuries, Frostick et al (1999) reported that approximately 30% of all baseball pitchers have a carrying-angle deformity and 50% have flexion contractures. Tullos and King (1973) found that two-thirds of pitchers who participated in their study had radiographic evidence of joint damage in the upper limb. They also suggested that about 50% of throwers participating in sports have either elbow or shoulder injuries which force them to cut short their careers. In a group of baseball pitchers undertaking treatment for chronic medial instability of the elbow, Conway et al (1992) found that 68% had a fixed flexion deformity. Additional studies have found that a sportsperson involved in a throwing sport has an increased chance of elbow pain/injury if they have an underlying shoulder injury (Shanley 2011, Fleisig & Andrews 2012). As a manual therapist, it is extremely important to assess and treat the shoulder complex when a patient presents with any elbow injury.

It is not only throwing sports that cause elbow injuries, however. Bethapudi et al (2013) found that over 50% of the elbow injuries sustained during the London 2012 Olympics were from judo and weightlifting. Other sports that are prone to elbow injury include wrestling (Molnár et al 2014), arm wrestling (Lee et al 2014b) and martial arts (Kreiswirth et al 2014).

Common elbow disorders

Elbow injuries may lead to a number of disorders, including lateral and medial epicondylitis, nerve compression syndromes and olecranon bursitis. These disorders of the elbow can occur following elbow dislocation, elbow instability, fractured bones, pulled muscles, ruptured tendons and sprained ligaments (see Table 11.3).

Elbow examination

Medical history

During the elbow joint examination, taking a detailed medical history of the patient is as essential as the physical examination itself. Chumbley et al (2000) suggest that the healthcare provider should seek information from the patient about recreational and occupational activities involving a repetitive load to the elbow, which could induce a chronic inflammation, cycle of microtrauma, necrosis, tissue degeneration and tendon rupture. The patient should be asked about pain, swelling, instability, locking or any other issues related to the elbow. In most cases, the narrative provided by the patient will provide information critical for narrowing the differential diagnosis and facilitating the elbow examination.

Red flags

The examiner must be aware of and note the presence of any of the red flag conditions listed in Table 11.4.

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