• Tennis : A biomechanical and therapeutic approach

PETER SCHNATZ, BA CHARLES STEUNER, DO

Lateral epicondylitis, one of the nosis, with emphasis on court biomechanics along most common lesions of the , affects some with currently available healthcare options. 50% of tennis players. This condition poses a Lateral epicondylitis is characterized by painful problem in clinical management because inflammation of the common extensor tendon at the treatment is dependent not only on proper outer region of the elbow. It was first noted in the medical therapy but also on correction of medical literature in 1873 by Runge,l and is one the improper on-court biomechanics. The of the most common lesions of the arm. Although most common flaw is a late contact on the fewer than 5% of the cases are found in tennis backhand groundstroke, forcing the player players, close to 50% of tennis players will have ten­ to extend the wrist with the extensor muscles. nis elbow at some point in their playing careers.2 This action predisposes to trauma of the ten­ In Hamilton's study,3 70% of patients with tennis don fibers at the lateral epicondyle. Under­ elbow were in the 35-to-54-year-old age group, standing the biomechanics will better pre­ while fewer than 2% were younger than 24 years. pare the physician to advise the patient and Hamilton also noted a high rate of relapse among to communicate with a tennis teaching pro­ treated patients.3 fessional to facilitate long-term relief. (Key words: , lateral epi­ Anatomic considerations condylitis, biomechanics, corticosteroids, The medical term for tennis elbow is derived from muscular manipulation) the involvement of the lateral epicondyle (Figure 1). This bony prominence on the lateral and distal In this article, we discuss the condition known as aspects of the acts as an attachment site lateral epicondylitis. Because of the high rate of for the common extensor tendon of the anconeus incidence among tennis players, the more com­ muscle and the extensor carpi radialis longus mon name is ''tennis elbow." The signs, symptoms, (ECRL) muscle. The tendon is also the attach­ and treatment among all those afflicted with ten­ ment for the extensor carpi radialis brevis (ECRB), nis elbow are similar; therefore, the information here extensor digitorum communis, extensor carpi should have universal application. This article ulnaris, and supinator muscles.4 The contraction contains topics of special interest to those involved of these muscles produces extension of the fore­ with tennis as participants, as teaching profes­ arm and extension and outward rotation of the sionals, and healthcare providers. We discuss wrist. It is thought that four of the muscles attached anatomy, pathophysiologic mechanisms, and diag- to the lateral epicondyle,l the anconeus, the supina­ tor, the ECRL, and the ECRBI are predisposed to Mr Schnatz is a tennis professional and medical student; traumatic forces or overuse leading to tennis elbow. Dr Steiner is professor and chairman, Department of Osteo­ The originates from the pos­ pathic Sciences, University of Medicine and Dentistry of terior aspect of the lateral epicondyle, inserts at the New J ersey-School of Osteopathic Medicine, Stratford, olecranon process, and functions to extend the NJ, and adjunct professor of bioengineering, Department of Engineering, Rutgers University, New Brunswick, NJ. at the elbow joint. The supinator muscle Correspondence to Mr Peter F. Schnatz, USPTA, 409 originates from the common extensor tendon, Trent Ct, Lindenwold, NJ 08021 inserts on the lateral aspect of the midradius, and (continued on page 782)

778 • JAOA • Vol 93 • No 7 • July 1993 Clinical practice · Schnatz and Steiner Extensor carpi radialis longus muscle

Anconeus muscle

Supinator Extensor carpi radialis brevis muscle

Figure 1. Posterior view of right forearm. Although extensor muscles have a common tendon on the lateral epicondyle, they all originate on a different location. This diagram emphasizes individual muscle attachments and hence their site of mechanical activity. acts to supinate or outwardly rotate the forearm. hematoma.6 When limiting our scope to tennis, Both of these muscles are at a mechanical disad­ however, we see that the mechanisms can be nar­ vantage because they are about one quarter of the rowed to the factors of age, overuse, and misuse. length of the bones that they move. As these mus­ More specifically, we can see how they relate to cles function, the torque created from the to and affect the enthesis of the lateral epicondyle. the point of muscular insertion will greatly increase Most cases of tennis elbow begin to appear in the force applied to the lateral epicondyle. 5 the middle thirties. It has been noted that adults Both the ECRL and ECRB function to extend in this age category begin showing changes in col­ and radially abduct the wrist. The ECRL origi­ lagen content, lipids, and in the ground substance nates from the lateral epicondyle and inserts at of the enthesis. A tendon that earlier in life might the base of the second metacarpal. The ECRB orig­ have compensated for the abusive forces on the inates directly from the extensor tendon and inserts elbow may now begin to lose elasticity and have a at the base of the third metacarpal. The ECRB is greater propensity for tearing. linked closely to wrist extension, radial abduction, Although the degenerative changes associat­ and supination. Because it is involved in the com­ ed with age are usually not enough in themselves mon but incorrect "wristy" backhand stroke, it is to cause problems, the addition of overuse and the muscle most frequently associated with lat­ abuse of the involved muscles can lead to ten­ eral epicondylitis. 6 dinitis of the proxllnal forearm extensors. Small tears may accompany the damage and lead to micro­ Pathophysiology hemorrhage, granulation tissue formation, and The list of pathophysiologic mechanisms attrib­ soft-tissue adhesions on the healing surface. The uted to the occurrence of lateral epicondylitis is region around the epicondyle becomes inflamed, with lengthy, and includes such conditions as radio­ a possible entrapment ofthe radial nerve; and, if humeral joint disease, overuse (occupational neu­ the trauma persists, fibrosis can occur. 2 ralgia), infection, bursitis, radial nerve entrap­ Tendons, though more resistant to one-direc­ ment, and periostitis 'associated with a localized tional tearing than muscles, are relatively avascular

782· JAOA· Vol 93 • No 7 • July 1993 Clinical practice • Schnatz and Steiner / Fo«ed to contact the ball Iale in o,d" to have a "might 'hot , (behind lead toot)

Net

Result of a circular ~~- motion without compensation

Figure 2. Representation of freeze-frame image of racquet head demonstrating circular swing that many players develop. This groundstroke leads to late contact with the ball, which is behind the lead foot, and produces disordered biomechanics. and slow to heaP As a muscle is worked, it has an extension. This decreased forearm extension is a increased demand for oxygen. The muscle obtains result of protective contraction of the and bra­ its nourishment from a rich blood supply. The ten­ chioradialis muscles.5 don, however, has no such nourishment. In the On physical examination, palpation anterior and case of an overworked muscle, the probability of ten­ distal to the lateral epicondyle should reveal nis elbow developing or a preexisting case being fur­ increased density and tenderness at the site of ther complicated is significantly increased. the common extensor tendon. Pain is most often increased on extension of the wrist and forearm. Diagnosis Supination against resistance may exacerbate the Usually, the clinician is able to diagnose lateral pain. One of the most reliable tests for tennis elbow epicondylitis on the basis of the patient's history is to extend the patient's middle finger, on the and the findings of the physical examination of affected side, against resistance. This maneuver puts the elbow. Onset may be sudden or gradual, but the a strain on the ECRB, which inserts at the base of pain will most likely be localized to the lateral the third metacarpaL aspect of the elbow with possible distal or proximal radiation. Often, the tennis-playing patient com­ Biomechanics plains of a weak grasp or increased pain on back­ Without question, the backhand is the most com­ hand shots. The weakness in the wrist and the mon stroke leading to tennis elbow, and will be hand may be observed by an increase in the shift­ used here for purposes of discussion. Directional ing of the racquet during off-center shots. It may references will be made with respect to right-hand­ be observed in the performance of similar off-court ed players. motions, such as turning a key or wringing a towel. Function of the aconeus muscle may also become Technique limited as discerned by a decrease in forearm A late backhand stroke and an off-center racquet

Clinical practice • Schnatz and Steiner JAOA • Vol 93 • No 7' July 1993' 783 Net

x

Ideal contact point

Figure 3. Representation offreeze-frame image of racquet head demonstrating a proper stroke. The face of the racquet is perpendicular to the vector of aim for an extended distance, allowing contact with the ball to be made slightly ahead of the lead foot. contact are the two basic stresses that lead to ten­ the force applied through the forearm to the elbow. nis elbow. A player starting a swing late is forced A larger racquet may also decrease the percentage to hit the backhand with an extended wrist. This of off-center shots due to the larger sweet spot. compensation will allow the racquet face to point forward at contact. It is common to see this play­ Grip size er lean back through the stroke to compensate for Grip size appears to be related to use of intrinsic a ball that is too close to the body. As the body and forearm. Some have leans back, the racquet face will tend to open at con­ argued that a larger grip will decrease the torque tact, and force the player to outwardly rotate at the lateral epicondyle,7 but this is an issue still (supinate) the forearm to keep the ball from going under debate. too long. The off-center force originates when the ball hits Biomechanical therapy the racquet outside of the "sweet spot" creates Correcting a late contact torque through the long axis of the racquet han­ Although there may be many factors that can lead dle. This torsion is translated into a shearing action to a late contact, the most common factor appears at the elbow. This motion can act as a potential to stem from a faulty follow-through. When most elbow strain or can compound the effects of trau­ beginning tennis players hear the word "swing," they matic forces due to improper technique.5 think of a baseball type of circular motion. When contact is made early during this type of motion, Equipment the ball will be hit wide to the right. The player then Although there have not been extensive studies compensates by finding the point in the arc of the on equipment as it relates to tennis elbow, pro­ swing that allows the ball to travel straight (Fig­ fessional experience has shown that both decreased ure 2). This swing forces the wrist to be extended racquet stiffness and string tension tend to decrease at contact. It also decreases the accuracy of the

784· JAOA· Vol 93 • No 7 • July 1993 Clinical practice • Schnatz and Steiner backhand by losing the margin of error obtained player to compensate at the last second by leaning in the proper follow-through. into or away from the ball. As noted earlier, how­ A long, extended follow-through maintains the ever, leaning backward at contact will tend to racquet face in the direction of aim for a much make the player supinate the forearm to keep the greater distance (Figure 3). The key is to correct the ball under control. An exercise that might help to contact point. The United States Professional Ten­ work on this requires a minimum of five small nis Association (USPTA) recommends that the steps before making contact with any ball. This backhand contact be made alongside the body and is not to say that if the ball is far away, the play­ slightly ahead ofthe lead foot.s Be aware, howev­ er would take small steps to get to the ball. The play­ er, that this maneuver will be impossible to do er must move rapidly to the ball, and then use without first correcting the initial problem of an the small steps to readjust his or her position. improper follow-through. It can be helpful to line The proper footwork should create a squeak up four balls (similar to the placement shown in on the hard courts or a shuffling sound on clay. Figure 2), take the racquet through the path of Because it is difficult to convey the importance the balls, and see where each ball would be direct­ and technique of proper footwork, creativity is ed. Then, line the balls up as shown in Figure 3; helpful. If the foregoing exercise is unsuccessful, now swing in this straight path, and observe the the following exercise may be tried. The player is increased margin of error. From contact forward, required to hold the heel of the racquet, or grip the racquet will be traveling from low to high, cre­ end, flat against his or her abdomen. The profes­ ated by a lifting motion of the arm. With the ten­ sional teacher or another person then tosses balls nis player's body weight forward and the wrist to the player. The player attempts to allow the firm, the trajectory of the racquet will move out­ ball to contact the center of the strings without ward perpendicular to the ground. Therefore, the moving the racquet. This exercise forces the play­ description of ''lift-out'' or suggestion to guide the er to move the feet and eliminates the need to racquet "through the ball" is a better visual clue reach with the arm. than "swing." When a player is unable to alter the stroke Racquet prepara,tion properly as a result of the "old dog/new trick" syn­ Taking the racquet back early seems like a small drome, two approaches may help. The first is to learn point; therefore, it is difficult to communicate the a totally new backhand stroke. If, for example, importance of doing so. Late preparation can only the original stroke was a flat swing, we might now foster a late contact and lead to biomechanical start from scratch and adopt a slice backhand with overload at the elbow. An interesting exercise is proper form. The slice backhand, when compared to watch beginning or club-level players and notice with a flat or top-spin backhand, involves a high­ that they almost invariably take their racquets to-low contact with the racquet face slightly "open" back as or after the ball is bouncing. Then, watch coming under the ball. The relative pronation at top-level competitors and observe that the play­ contact will decrease contraction of the muscles ers take the racquet back well before the ball has coming off the lateral epicondyle and increase the bounced and possibly before the ball crosses the net. use of the muscles originating from the medial epicondyle. This form can be used in treating the Alterations in equipment patient-tennis player because the slice backhand As discussed in the section on biomechanics, it helps to prevent contraction of the muscles involved may be helpful to switch the player to a more flex­ in tennis elbow. If this alteration does not work, it ible racquet with a larger sweet spot. Advising may be necessary to introduce a two-handed back­ the player to decrease the tension of the strings hand stroke, which tends to protect the extensors is also of benefit. Because grip size may be relat­ and supinators of the dominant arm. ed to torque at the lateral epicondyle, it is rea­ sonable to consider this alteration in designing Footwork treatment. Because these relationships are difficult Top-level players, after moving to the vicinity of to measure quantitatively and vary based on each the ball, will fine-adjust their position with sev­ player's unique anatomy, a specific grip size can­ eral small steps. This process allows the body posi­ not be recommended. The best advice is to find tion and stroke to be consistent from shot to shot the largest grip that is still comfortable, which and hence the player will have a well "grooved" may minimize the potential for torque injury to stroke. Lack of the small-step adjustment forces the the lateral epicondyle.

Clinical practice • Schnatz and Steiner JAOA· Vol 93 • No 7 • July 1993·785 Conditioning 10 minutes. For players having more acute pain, Conditioning will not only maintain joint mobili­ or for professional players who must carry through ty during recovery and help to prevent future com­ with tournament play, the warm-up can be enhanced plications, but it also can prevent tennis elbow by soaking the elbow in a basin of hot water for 30 from developing in the first place. Conditioning minutes. For players having severe pain, the elbow should emphasize adequate warm-up techniques, is packed in ice for 2 hours after play. No brace, "sup­ increasing flexibility, and improving muscle port," or band is used because the compression of endurance. The best warm-up approach is to go the forearm has reduced the circulation without pro­ through the motions of each stroke repetitively tecting the joint. first without the racquet, then with the racquet before hitting the ball. This prepares the tissues Medical therapy and lubricates the joint structures. Overview Exercises provide a full warming of the tis­ In treating lateral epicondylitis, the objective should sues before actual contact is made with the ball. be to heal the damaged tissues and retain proper Muscles, ligaments, and tendons that have been function of the joint muscles. Successful treatment thoroughly warmed up are likely to stretch. Those is dependent in part on correction or modification that are cold are more likely to tear. The older the of the biomechanical aspects of the tennis tech­ player, the more important is the warming-up nique. Failure to do so will result in immediate process. A full range of motion should be produced reinjury, which is most likely the reason for the in the wrist, the elbow, the , and the entire high rate of relapse in Hamilton's study.3 Over the body before the final stress of ball contact. The years, many treatment modalities have been devel­ exercises previously described9 consist largely of oped. Among them are immobilization, injections swinging the trunk from side to side in a sway­ of corticosteroids, ultrasound, acupuncture, surgery, ing fashion, first without the racket and then with and commercial braces. Rest is frequently advocated. it. A general loosening swinging motion of the 'lbtal immobilization, however, may promote mus­ trunk can be done most effectively with the cle degeneration, decreased range of motion, pro­ swinging loosely. The player stands with feet apart, tective contraction of surrounding muscles, and toes pointed out, and totally relaxed shortening of scar tissue due to fibrosis. A clearer and loose, and then gently rotates back and forth interpretation of this advice might be to achieve rest by turning the hips. This exercise is intended for from traumatic forces. Certainly, any motion that improving joint function and encouraging heal­ aggravates the elbow or causes further abusive ing. It should be done for 1 minute every 2 hours forces should be avoided. Such avoidance may before any sport activity, and it can be used to involve abstinence from hitting backhand strokes break up any period of immobilization. until the technique has been modified. Not only After doing the· foregoing exercise for 3 or 4 should a physician and a tennis teaching profes­ minutes; the tennis player picks up the racquet sion be involved in this process, but they also and continues the motion to turn the body through should work in concert. its full range of motion back and forth repetitive­ ly until the motion becomes loose. During this Recommended therapy process, the enhanced blood supply increases the We have found that the most effective treatment capacity of the tissues to perform without injury. regimen includes relief of inflammation, restora­ The tennis player should place the left hand on tion of tissue integrity, and maintenance of joint the throat of the racquet, so that during the swing motion. The first step of the treatment involves the racket is carried all the way back with both an injection of an anti-inflammatory agent, a 0.1- hands and full body motion is encouraged. When mL combination of dexamethasone (0.02 mg) and the backhand stroke is used, the whole body-not lidocaine (0.005 mg). The lesion must be palpated just the hand-moves into the ball. and the injection accurately administered because In the early phases of the swinging, players delivery as much as 2 mm from the primary region apply neither speed nor power. Players in acute may be valueless. Any involved muscle of the fore­ pain or without an opportunity to play should do arm, shoulder, or cervical region is stretched and these exercises daily. If the pain is reduced enough manually manipulated to relieve protective mus­ so that play is possible, the player must perform cular contractions. Often, this manipulative treat­ these exercises diligently before play. During the ment is repeated two to four times at weekly inter­ course of treatment, the warm-up should last at least vals.

786· JAOA · Vol 93 • No 7· July 1993 Clinical practice • Schnatz and Steiner Current thoughts on steroid injections According to the American Hospital Formu­ Corticosteroid injections have been the tradition­ lary Service Drug Information,12 when glucocor­ al mainstay of tennis elbow therapy. Current ticoids are used for their anti-inflammatory prop­ thought on injections is consistent with two stud­ erties, they are not curative and rarely are indicated ies by Price and colleagues.10 The first, a double­ as the primary treatment method. Glucocorticoids blind study, compared 2 mL of 1% lidocaine with should be used as adjunctive therapy with other either 10 mg of triamc;:inolone or 25 mg of hydro­ treatment procedures.12 The use of exceptionally co'rtisone made up to 2 mL of solution with 1% small doses is therapeutically sufficient to reduce lidocaine. Although the steroid preparations showed inflammation while small enough to avoid any tis­ much greater effect at 8 weeks, the degree of sue distortion. The addition oflidocaine probably improvement was similar for all three at 24 weeks. increases the tissue permeability so that glycos­ The researchers concluded that 10 mg oftriamci­ aminoglycans can be accepted into the injured ten­ nolone yielded more rapid relief of symptoms than don fibers. Manual stretching of the muscles, with 25 mg of hydrocortisone or lidocaine alone. Although encouraged activity, will restore joint mobility. there may be less need to repeat injections with 10 After this approach, full range of motion will be mg of triamcinolone, skin atrophy may occur more maintained with increased blood supply promot­ often. Six months postinjection, corticosteroid treat­ ing tissue healing. Correction of on-court biomechanics ment appeared to offer no advantage over lido­ will eliminate the traumatic force at the lateral caine. From their second study, they concluded epicondyle and prevent relapse of the condition. that doubling the dose of triamcinolone to 20 mg Although we have seen successful results, a con­ yielded no noticeable improvement. Studies such trolled study is needed to document the validity of as these have lead to the widespread use of steroids this technique. in tennis elbow therapy, but their effectiveness is not supported by our experience. Other modes of therapy The advantage of corticosteroid injections over Ultrasound therapy has potential advantages saline solution or local anesthetics, in fact, has when its ability to cross myofascial planes is con­ only been demonstrated in one study.ll Because sidered, yet.a study> has shown only 63% of patients initial improvement in several of the patients in improved with this treatment. A study on acupunc­ their study was not sustained, Price and associ­ ture13 resulted in no cases worsening, no reported ateslO argue that the 6-month outcome is a reflec­ side effects, and 62% of patients showing signifi­ tion of the natural course of tennis elbow. If this is cant improvement. Therefore, acupuncture may a valid argument, steroid injections are probably be an alternative conservative treatment when of transient benefit, not influencing a trend toward other approaches are unsuccessful. Surgical inter­ healing. vention has been reported by some14 to have a Based on the first study,lO the problems relat­ 90% success rate. We would be more comfortable ed to injection therapy included postinjection wors­ with these statistics if we did not see so many ening of pain·in nearly half of all steroid-treated patients in whom surgery was. ineffectual. patients. Relapses of symptoms and skin atrophy Although braces are commonly recommend­ were reported in all three groups. Our clinical ed, commonly used, and provide many people with experience suggests that large-dose steroids not a feeling of confidence, they may be causing more only cause local tissue distortion, but can also harm than good. The brace functions to limit the enter the vasculature, resulting in the potential motion of muscles and increases the ohance of los­ for systemic complications. ing motion, which may never be regained. The As a one- or tw(}-time treatment, the steroid injec­ elbow joint is not protected and is still suscepti­ tions are effective at reducing inflammation, but ble to torsion. Compression of the foreann reduces fail to address the protective contraction of sur­ circulation and does not promote tissue healing. rounding muscles. This contraction results in diminished mobility in the elbow joint, and a rel­ Discussion ative decrease in vascular supply to the damaged Lateral epicondylitis is a very common condition tissue due to the increased oxygen demand by con­ affecting close to half of all tennis players. Although tracting muscles. It seems likely that this phe­ degenerative changes due to age playa role, over­ nomenon decreases the possibility of actual tis­ load forces applied to the lateral epicondyle region sue restoration, and henoo the high incidenoo of tennis create the most significant factor. The initial mus­ elbow reinjury. culotendinous lesion, if permitted to continue, can

Clinical practice • Schnatz and Steiner JAOA· Vol 93 • No 7· July 1993 • 787 be further complicated by fibrosis and vascular insufficiency. The diagnosis of tennis elbow is usu­ ally straightforward, but the correction and treat­ ment will require more effort. Changes in tennis equipment are relatively easy, but the main cause of the problem, improper technique, may be frus­ trating and time-consuming to modify. The end result, however, will be a stroke with greater mar­ gin of error, increased inconsistency, and no pain on the backhand motion. Treatment from a healthcare professional should begin as soon as possible. Consider the dif­ ferent treatment options while paying particular attention to those that advocate restoration of tis­ sue integrity while motion of the joint is main­ tained.

References 1. Runge F: Zur Genese und behandlung des Schreiberkrampfs. Berd Kiln Woch 1987;10:245-248. 2. Chop W: Tennis elbow. Postgrad Med 1989;86:301-308. 3. Hamilton P: The prevalence of humeral epicondylitis: A survey in general practice. J R Coll Cen Pract 1986;36:464-465. 4. Morris H: Human Anatomy. New York, NY, Blakiston Co, 1953, pp 472-478. 5. Steiner C: Tennis elbow. JAOA 1976;75;575-58l. 6. Chard MD, Hazleman BL: Tennis elbow-A reappraisal. Br J Rheumatol1989;28(3):186-190. 7. Bernhang A: Prevention and treatment of tennis elbow. The Physician and Sports Medicine February 1977, p 4l. 8. United States Professional Tennis Association, Inc: Tennis: A Professional Guide. Tokyo, Japan, Kodansha International Ltd, 1984, P 63. 9. Steiner C: Tennis elbow. JAOA 1976:75:575-58l. 10. Price R, Sinclair H, Heinrich I, et al: Local injection treatment of tennis elbow-Hydrocortisone, triamcinolone, and lignocaine compared. Br J Rheumatol 1991 ;30:39-44. 11. Day B, Govindasamy N, Parnaik R: Corticosteroid injections in the treatment of tennis elbow. Practitioner 1978;220:459-462. 12. McEvoy G (ed): AHFS Drug Information. Bethesda, Md, Amer­ ican Society of Hospital Pharmacists, Inc, 1990, p 1723. 13. Brattberg G: Acupuncture therapy for tennis elbow. Pain 1983;16:285-288. 14. Leach RE, Miller JK Lateral and medial epicondylitis of the elbow. Clin Sports Med 1987;6(2):259-272.

788· JAOA· Vol 93 • No 7 • July 1993 Original contribution • Schnatz and Steiner