VI. RESPUESTAS A LOS CRITERIOS Y SUBCRITERIOS
3. Método de Solución de Problemas y Herramientas de la Calidad
*Marc R. Safran, MD
Introduction
Because the medial elbow is subject to significant forces during sports activities, this area of the elbow is fre- quently injured. Appropriate diagnosis and treatment require a detailed understanding of the normal anat- omy of the elbow and the pathophysiology of injuries to the medial elbow.
The anatomic structures of the elbow provide stabil- ity through a complex range of motions: flexion- extension and pronation-supination. The dynamic stability seen in the elbow depends on varying contri- butions from the osseous, ligamentous, and other soft- tissue structures about the elbow.
Pathophysiology and Pathomechanics
The elbow may be subjected to numerous unusual forces during sports activities. Overhead athletes sub- ject their elbows to major valgus forces that place the elbow at risk for specific elbow injuries. Sports such as baseball, football, tennis, volleyball, golf, and water polo are most commonly associated with acute and chronic elbow pathology. Overhead throwing athletes are predisposed to overuse syndromes secondary to re- petitive, high-velocity stress across the elbow. The high- est stress at the elbow occurs during the late cocking and acceleration phases of the throwing cycle. Studies have indicated that the valgus stress at the elbow dur- ing the acceleration phase can be as high as 64 N-m, which exceeds the ultimate tensile strength of the ulnar collateral ligament (UCL).1Although the curveball has
long been implicated in UCL injury in young baseball players, biomechanical analysis has not supported this claim.2 In baseball, the number of pitches (during a
game, season, and year) is considered the most impor- tant factor for elbow injury, although the type of pitches, pitching mechanics, and physical conditioning are still considered potentially important.2-4 The
stresses of throwing result in loads that produce trac- tion or tensile forces on the medial-sided structures,
compression forces on the lateral side of the elbow, and medially-directed shear posteriorly.5,6The athletes com-
monly have chronic and acute injuries to the UCL with or without medial epicondylitis, as well as ulnar nerve symptoms. Laterally, compression leads to radiocapitel- lar degeneration and loose bodies, and posterior shear forces may lead to osteophyte formation, loose bodies, and olecranon stress fractures.
Medial Epicondylitis
Medial epicondylitis is a term for tendinosis at the common medial flexor-pronator origin. Specifically, the origins of the flexor carpi radialis and the pronator teres are most affected. This injury is actually a tendi- nosis, and thus the term epicondylitis is a misnomer. Medial epicondylitis is much less common than lateral epicondylitis in the general population. Young to middle-aged athletes involved in golf, tennis, and over- head throwing are most commonly affected. Although medial epicondylitis is also known as golfer’s elbow, it is more common than lateral epicondylitis in profes- sional tennis players. The repetitive valgus stress of these sports activities subjects these muscles to mi- crotraumatic injury.
The peak incidence of medial epicondylitis occurs in the fourth and fifth decades of life. Patients generally re- port medial elbow pain that is worse with gripping, bat- ting, hitting a serve in tennis, or throwing, and, less com- monly, swelling of the inner elbow. Patients have medial elbow pain and sometimes symptoms of ulnar nerve ir- ritation. Examination reveals tenderness over the medial epicondyle and slightly distal and lateral in the pronator teres tendon, as well as pain with resisted pronation or wrist flexion. Careful assessment for UCL laxity and ul- nar nerve symptoms is required because medial epi- condylitis may occur simultaneously. Radiographs are usually normal. MRI is not usually necessary for the di- agnosis of medial epicondylitis, but the changes seen are consistent with a tendinosis or may be more extensive and include muscular and/or bony edema.
The treatment generally is nonsurgical, consisting of rest and anti-inflammatory medications, with a gradual return to stretching and strengthening of the involved muscles. In more than 80% of patients, symptoms resolve with conservative treatment, and the patient is able to return to the sport or activity. Cortisone
*Mark R. Safran, MD or the department with which he is affili- ated has received research or institutional support from Smith & Nephew; holds stock or stock options in Cool Systems, Inc; and is a consultant for or an employee of Cool Systems, Inc.
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injections may be of benefit as an adjunct to rehabilita- tion.7 Rehabilitation includes application of ice, anti-
inflammatory medications, and stretching and strength- ening of the flexor/pronator muscle group. A counterforce brace may be beneficial in patients who are rehabilitating but still involved in activites that may aggravate the symptoms.
If the condition does not respond to an appropriate trial (4 to 6 months) of nonsurgical treatment, surgery may be required. Surgical intervention involves excision of the abnormal degenerative tissue at the common flexor-pronator origin and reapproximation of the re- maining healthy tissue. Unfortunately, the surgery for medial epicondylitis is not as successful as that for lat- eral epicondylitis. Part of the reason for decreased suc- cess is failure to recognize concomitant disease. Ulnar neuropathy is present 40% to 60% of the time. The success of medial epicondylitis débridement is signifi- cantly reduced when concomitant ulnar neuropathy is a factor.8According to one study, 96% of patients treated
for medial epicondylitis without ulnar nerve symptoms had good to excellent results, compared with only 40% good to excellent results in patients with concomitant moderate to severe ulnar neuropathy requiring ulnar nerve decompression or transposition at the time of
medial epicondylitis surgery.8Furthermore, UCL insta-
bility should be suspected in throwing athletes, and the appropriate work-up needs to be done in these pa- tients.6
UCL Injury
Anatomy
The UCL is a ligamentous complex on the medial as- pect of the elbow between the distal humerus and the proximal ulna. Its anterior portion, the anterior oblique ligament (AOL), is the primary restraint against valgus stress, especially the forces associated with throwing.9-13
The AOL consists of an anterior band, which is taut at 0° to 60° flexion, and a posterior band, which is taut at 60° to 120° of flexion.12The anterior band is primarily
responsible for stability against valgus stresses at 30°, 60°, and 90° of flexion, making it the most important for overhead sports activities.13 The posterior band of
the AOL begins as a secondary restraint to valgus sta- bility at 30° and 90° and is a primary restraint to val- gus force at 120° flexion.11 The posterior oblique liga-
ment forms the floor of the cubital tunnel and plays more of a role in restraint against valgus stress at higher degrees of flexion. The role of the transverse lig- ament (Cooper’s ligament) in elbow stability remains unclear.
Recent studies have demonstrated that the flexor- pronator muscles, particularly the flexor carpi ulnaris, in addition to the flexor digitorum superficialis and flexor carpi radialis, play a significant role in providing valgus stability of the elbow and are activated at higher levels in patients with medial elbow pain.14-16
Pathomechanics
Overhead throwing athletes subject their elbows to se- vere and repetitive valgus stress, placing the anterior band of the AOL of the UCL complex at risk of injury. Chronic UCL insufficiency results from microscopic tears and attenuation. Patients report pain and soreness in the medial elbow with throwing, usually in the late cocking or early acceleration phases or with ball re- lease. Specifically, such athletes are unable to throw at more than 75% of maximal effort. Acute rupture can also occur with or without chronic changes. Most acute UCL ruptures (87%) occur midsubstance.17 Ulnar and
humeral avulsions are much less common. Athletes of- ten report the sudden onset of pain and the feeling of giving way during throwing. The most common situa- tion is an acute exacerbation of a chronically injured ligament. Associated pathology, such as ulnar neuropa- thy, loose bodies, osteophytes, and a flexion contrac- ture, also can produce symptoms.
The stresses of throwing result in a consistent pat- tern of potential elbow injuries: traction or tensile forces of the medial-sided structures, compression of the lateral side of the elbow, and medially directed shear posteriorly5,6(Figures 1and2). The tensile forces
Figure 1 Schematic representation of the effects of valgus force as seen from the anterior elbow. Valgus forces applied to the elbow result in tensile forces medially, to the UCL and ulnar nerve, and the flexor-pronator muscle group, which may be injured during excessive eccentric contraction. Laterally, the radiocapitellar joint is a secondary restraint to valgus force, and thus compression of this joint may result in chondral injury. (Re-
produced with permission from Safran MR: In- jury to the ulnar collateral ligament: Diagnosis and treatment. Sports Med Arthrosc Rev 2003;11:17.)
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lead to attenuation or tearing of the UCL, either chronic or acute. Acute or overuse injury to the flexor- pronator muscle-tendon group may occur as the tensile valgus forces are dynamically resisted. Ulnar nerve symptoms also may develop in conjunction with UCL injury. An acute UCL tear may result in bleeding near the nerve, causing nerve irritation as well as compres- sion from the swelling. A chronic UCL injury may re- sult in ulnar nerve symptoms from several different po- tential causes: (1) increased tensile force as the nerve is stretched at the elbow as a result of increased medial joint gapping from the incompetent ligament and/or (2) compression from a tight cubital tunnel due to scarring or ossification of the UCL or osteophytes. Incompe- tence of the UCL also may result in increased compres- sive force at the radiocapitellar joint, a secondary stabi- lizer to valgus force, which leads to softening and degeneration of the articular cartilage (Figure 1). Os- teochondral loose bodies may result and cause mechan- ical symptoms and pain. Eventually, degenerative ar- thritis of the radiocapitellar joint may develop. Posteriorly, the olecranon is repeatedly and forcefully driven into the olecranon fossa with throwing as the arm goes into extension. Further, valgus stress typically causes shearing posteriorly; this results in impingement of the posteromedial olecranon against the lateral as-
pect of the medial wall of the olecranon fossa, which results in chondromalacia, synovitis, and pain (valgus extension overload syndrome [VEOS]; Figure 2). Ac- cording to a 2004 study, UCL injury results in contact alterations in the posterior compartment that lead to osteophyte formation.18 Compounding this posterior
impingement is the bony hypertrophic narrowing of the olecranon fossa and hypertrophy of the proximal ulna that occur in overhead athletes who have participated in sports since childhood. With persistent impaction and shear forces, the osteophytes may break off and be- come loose bodies within the joint.19,20 These loose
bodies can get caught in the joint surfaces and damage the articular cartilage.
Evaluation
Patients generally have point tenderness at the insertion on the ulna, 2 cm distal to the medial epicondyle. UCL deficiency should be tested with the elbow at 30° to 120° of flexion. The valgus stress test has been de- scribed with the elbow at 30° of flexion(Figure 3). The milking maneuver and its modification assess for valgus laxity at a higher degree of flexion.5In this test, the pa-
tient’s arm is stabilized proximally, while the thumb is pulled laterally, imparting a valgus stress to the elbow in 70° to 90° of flexion, while the examiner palpates the medial joint line for opening(Figure 4). The mov- ing valgus stress test (during which the elbow is brought from full flexion into extension with constant valgus force reproducing the patient’s medial pain) has recently been described, although the pain from the UCL usually is reproducibly present between 80° and 120° of flexion21 (Figure 5). It is important that the
Figure 2 Schematic representation of the effects of valgus force as seen from the posterior elbow. The olecranon is forced in the tight-fitting olecra- non fossa. With valgus force, there is an addi- tional shear force of the olecranon against the medial wall of the olecranon fossa. This may result in chondral injury, osteophyte formation, and loose bodies. (Reproduced with permission
from Safran MR: Injury to the ulnar collateral ligament: Diagnosis and treatment. Sports Med
Arthrosc Rev 2003;11:17.)
Figure 3 Valgus stress test of the elbow. With the patient seated and the hand placed between the exam- iners’s chest and arm, a valgus force is applied to the elbow that is bent at 30º. The medial joint is palpated, with gapping of the joint sur- faces. (Reproduced with permission from Safran
MR, Caldwell GL III, Fu FH: Chronic instability of the elbow, in Peimer CA (ed): Surgery of the
Hand and Upper Extremity. New York, NY,
McGraw-Hill, 1996, pp 467-490.)
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examiner evaluate for VEOS (posterior elbow impinge- ment) because studies have shown that 42% of patients who undergo surgery for VEOS require a second oper- ation, and 25% of these patients required a UCL recon- struction as a result of valgus instability.22Patients must
also be evaluated for medial epicondylitis and ulnar neuritis, as well as for lateral elbow tenderness that is worsened by pronation and supination of the elbow be- cause this may be indicative of radiocapitellar degener- ation.
Physical examination of the throwing athlete with elbow pain, and potentially UCL injury, should also in- clude evaluation of the shoulder, particularly the scapu- lothoracic joint (scapular malposition, inferior medial scapular winging, coracoid tenderness, and scapular dyskinesis [the SICK scapula]; and dyskinesis), core strength, and hip motion (rotation) and strength, as a breakdown in the kinetic chain may place the elbow at increased risk for injury and potentially play a role in the outcome of nonsurgical treatment.
Stress radiographs can be helpful for demonstrating UCL insufficiency.6,23 With the elbow flexed approxi-
mately 20° to 45°, an AP radiograph is taken while a valgus stress is applied.23 With UCL insufficiency, gap-
ping at the medial joint line exceeds that of the con- tralateral normal side by more than 2 mm. This may be done manually or with an instrumented device. Plain radiographs may also show secondary changes of chronic UCL insufficiency, such as osteophyte forma-
tion at the medial joint, loose bodies, sclerosis, radio- capitellar degeneration, or osteophytes of the olecra- non. MRI can be helpful for detecting a torn UCL and for defining associated pathology.23However, magnetic
resonance arthrography is even more sensitive (97%) in detecting UCL injury.24,25 Studies have shown ultra-
sonography to be useful in detecting UCL injury and changes in the ligament and medial joint opening with valgus stress, although it continues to be used only sparingly at this time because it is technician depen- dent.26,27
Treatment
The initial treatment of UCL injury generally is nonsur- gical and consists of rest from the overhead sport, anti- inflammatory medications, and physical therapy.5The
first goal of treatment is to establish a painless range of motion that also will allow the ligament to heal. Grad- ual strengthening should begin with isometric exercises of the elbow and wrist. Strengthening should focus on the flexor pronator muscles, which recently have been shown to be important local dynamic stabilizers of the medial elbow.14-16A shoulder program should be imple-
mented to normalize range of motion and flexibility and improve shoulder strength. Once full motion, full strength, and dynamic stability have returned and the patient is symptom free, the patient may begin an inter- val throwing program. Upon satisfactory completion of the interval throwing program (pain-free throwing at full velocity), the patient may return to high-level activity.
Figure 4 Modified milking maneuver. The patient’s elbow is flexed 70º while the shoulder is externally ro- tated. The examiner palpates the medial joint with one hand while the other hand pulls dis- tally on the patient’s thumb, imparting a valgus force. The advantage of this position of exami- nation is that external shoulder rotation, which may confound the examination, is eliminated. (Reproduced with permission from Safran MR:
Injury to the ulnar collateral ligament: Diagnosis and treatment. Sports Med Arthrosc Rev 2003;11:19.)
Figure 5 Moving valgus stress test. With the patient’s shoulder in abduction and external rotation, the elbow is flexed and extended while a valgus force is imparted on the elbow (by externally rotating the shoulder). Pain felt at a particular point within an arc of 80° and 120° is consistent with an injury to the UCL. (Reproduced with
permission from Safran MR: Injury to the ulnar collateral ligament: Diagnosis and treatment.
Sports Med Arthrosc Rev 2003;11:20.)
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One study indicated that approximately half of pa- tients with UCL injury can be treated successfully with- out surgery and are able to return to the same level of athletic activity.28 Surgery is indicated if symptoms re-
cur after an appropriate trial of nonsurgical treatment. Surgical treatment of a UCL injury also should be con- sidered with acute ruptures in high-level throwing ath- letes, with significant chronic instability, and after dé- bridement of UCL calcification.
When nonsurgical treatment of UCL injuries fails, surgical options must be considered.6 Surgical treat-
ment of the UCL depends on several variables. Cur- rently, the mainstay of surgical treatment is UCL recon- struction. Primary repair of acute ruptures of the UCL had been advocated for years; however, ligamentous re- construction now has consistently better results over- all.5,6The less common avulsion injury is considered by
some to be amenable to suture repair.17,29Repair of the
torn UCL was the treatment of choice until 1992, when a study reviewed the results of repair and recon- struction.17 Those authors recommended reconstruc-
tion, citing the finding that overhead athletes per- formed significantly worse with repair than with reconstruction. The study also noted that repair could be considered if the tear was a proximal avulsion, if the procedure was performed soon after injury, if the rest of the ligament was undamaged, and if no ulnar nerve symptoms were present. Repair of most injuries usually involves repair of tissue that frequently is chronically injured and therefore not ideal tissue. There was not much in the literature about repair until a recent study reported a series of 60 patients with an average age of 17 years who underwent UCL repair, predominantly with proximal and distal insertional injuries.29 A 93%
success rate at 5-year follow-up was reported, with 4 patients (7%) having failed repair (early and late re- pair, two patients each). Generally, however, UCL re- construction with a free graft has become the treatment of choice for UCL deficiency.
UCL reconstruction has evolved considerably over the years.6,30It was reported that 81% of patients were
able to return to the same level of sports activity after UCL reconstruction, compared with 63% of patients who had primary repair.24 The rate of surgical success
of reconstruction has reliably and reproducibly im- proved from 68% with Jobe’s original report to up to 97%, with success defined as the patient returning to play at the same level or better than before the injury.6,24,31-38
Several graft options are available. An ipsilateral