Partial repair of irreparable rotator cuff tears

Arthroscopy: The Journal of Arthroscopic and Related Surgery 10(4):363-370 Published by Raven Press, Ltd. © 1994 Arthroscopy Association of North America

Partial Repair of Irreparable Rotator Cuff Tears

Stephen S. Burkhart, M.D., Wesley M. Nottage, M.D., Darrell J. Ogilvie-Harris, M.D., Harvey S. Kohn, M.D., and Anthony Pachelli, M.D.

Summary: This study analyzes the results of a previously unreported technique of reconstruction for the massive irreparable rotator cuff tear. The technique involves repair of the margins of the tear to restore the force couples and "suspension bridge" system of force transmission in the shoulder. Complete coverage of the defect was not considered to be essential as long as the normal mechanics of the shoulder were restored and the rotator cuff tear was con- verted to a "functional cuff tear." This procedure was performed on 14 patients. Improvement in function was dramatic. Active elevation (elevation denotes the plane of motion midway between the planes of shoulder abduction and shoulder flexion; elevation is reported because it is the most functional plane in which to raise the arm) improved by 90.8°: from a preoperative average of 59.6 ° to a postoperative average of 150.4 °. Strength improved an average of 2.3 grades on a 0-to-5-point scale. The average score on the UCLA Shoulder Rating Scale improved from a preoperative value of 9.8 to a postoperative value of 27.6. All but one patient was very satisfied with his or her result. The authors are of the opinion that this technique is preferable to other reconstruc- tive techniques, such as tendon transposition, that emphasize coverage of the defect at the expense of destroying the normal mechanics of the shoulder. The authors suggest that partial repair of massive irreparable rotator cuff tears should supplant tendon transposition as the procedure of choice for this con- dition. Key Words: Shoulder--Rotator cuff surgery--Shoulder surgery-- Biomechanics.

In 1934, Codman (1) published his famous pio- neering work on the ro ta tor cuff, advising repair of symptomat ic ro ta tor cuff tears. As surgical techniques evolved for large cuff tears, the concept of " repai r ing the t e a r " somehow became translated to "cover ing the ho le . " Unfor tunate ly , the concept lost a great deal in the translation.

Large ro ta tor cuff tears may not be amenable to complete p r imary repair. The less re t racted edges

From the University of Texas Health Science Center at San Antonio, San Antonio, Texas (S.S.B.); University of California, Irvine, California (W.M.N.); The Toronto Hospital, Toronto, Ontario, Canada (D.J.O.); Sports Medicine and Knee Surgery Center, Milwaukee, Wisconsin (H.S.K.); and New Mexico Or- thopaedic Associates, Albuquerque, New Mexico (A.P.), U.S.A.

Address correspondence and reprint requests to Dr. Stephen S. Burkhart, 540 Madison Oak Drive, Suite 620, San Antonio, TX 78258-3913, U.S.A.

of the tear near the anter ior and poster ior margins are usually reparable, but the central por t ion of the tear with the greatest retract ion may be irreparable. For that reason, a number of heroic reconst ruct ive operat ions have been devised to obtain coverage of the residual hole in the cuff. These reconst ruct ive operat ions have included p lacement of autogenous graft (2), f reeze-dried allograft (3), supraspinatus muscle advancement (4), and t ransposi t ion of por- tions of intact rota tor cuff musc le - t endon units (5- 9). But is coverage of the hole necessary for pain relief and good function?

One of us (S.S.B.) has introduced the concept of the "funct ional rota tor cuff t e a r " (10). This is a tear that is anatomical ly deficient yet b iomechanical ly intact. Patients with functional rota tor cuff tears have normal function despite unrepaired holes in the rota tor cuff. This concept has provided a bio-

363

364 S. S. B U R K H A R T ET AL.

mechanical rationale for debriding rather than re- pairing selected rotator cuff tears. This idea is further supported by recent investigations (11,12) that confirmed normal function and good clinical results in patients who had residual rotator cuff defects after repair. These residual defects have been dem- onstrated by ultrasonography (11) and arthrography (12). Further support of the concept of the functional rotator cuff tear comes from a kinematic study of patients with known unrepaired tears of the rotator cuff (13). Fluoroscopic imaging of shoulders with known unrepaired tears of the supraspinatus plus a portion of the infraspinatus showed normal kinematics with a stable fulcrum of glenohumeral motion.

The purpose of the present study is to introduce the concept and rationale of partial rotator cuff repair as a reasonable treatment alternative in the irreparable tear, converting the tear to a functional rotator cuff tear that is biomechanically intact. This is accomplished through partial repair of the cuff by restoring the shoulder's force couples and its cable system of force transmission (10,14,15).

MATERIALS AND METHODS

This study was initiated as a result of a question- naire sent to members of the Shoulder Arthroscopy Study Group to identify those members who had experience with partial repair of massive irreparable rotator cuff tears. Each of the five authors con- tributed patients to this study.

The study population was composed of 14 patients (nine men and five women), each with one involved shoulder. The dominant extremity was involved in 10 patients; the nondominant extremity was involved in four patients. Patients ranged in age from 38 to 77 years (average 56).

All patients were examined at follow-up by the operating surgeon. Follow-up ranged from 9 to 62 months (average 20.8).

The University of California at Los Angeles (UCLA) Shoulder Rating Scale (16) (Table 1) was used to evaluate shoulder pain, function, and motion, as well as satisfaction. EUman's criteria (16) were then used to group the final results into excellent, good, fair, and poor categories.

The mechanism of injury involved lifting in six patients and a direct blow or fall onto an out- stretched hand in another six patients. Two patients could not recall a specific injury.

Pain and weakness were the preoperative corn-

TABLE 1. U C L A S h o u l d e r R a t i n g Sca l e a'b

Score

Pain Present always and unbearable; strong medication

frequently 1 Present always but bearable; strong medication

occasionally 2 None or little at rest; present during light

activities; salicylates used frequently 4 Present during heavy or particular activities only;

salicylates used occasionally 6 Occasional and slight 8 None 10

Function Unable to use limb 1 Only light activities possible 2 Able to do light housework or most activities of

daily living 4 Most housework, shopping, and driving possible;

able to do hair and to dress and undress, including fastening brassiere 6

Slight restriction only; able to work above shoulder level 8

Normal activities 10 Active forward flexion

~>150 ° 5 120-150 ° 4 90-120 ° 3 45-90 ° 2 30--45 ° 1 <30 ° 0

Strength of forward flexion (manual muscle testing)

Grade 5 (normal) 5 Grade 4 (good) 4 Grade 3 (fair) 3 Grade 2 (poor) 2 Grade 1 (muscle contraction) 1 Grade 0 (nothing) 0

Satisfaction of the patient Satisfied and better 5 Satisfied and worse 0

a Maximum score 35 points; excellent, 34--35; good, 28-33; fair, 21-27; poor, 0-20.

t, Satisfactory, excellent + good; unsatisfactory, pain + poor.

plaints in all patients. The duration of symptoms before surgery ranged from 2 to 24 months (average 9.8).

The preoperative disability in these patients was extreme, as evidenced by their poor motion and strength, and very low UCLA scores. The preoperative average for forward elevation was 59.6 ° . Pre- operative strength of forward flexion averaged 2.1 (on a 0-to-5-point scale). The preoperative UCLA score ranged from 7 to 13 (maximum score 35; average 9.8). All the preoperative UCLA scores placed them well down in the " p o o r " category (poor, 0-20 points).

All patients underwent attempted open rotator cuff repair. When the tears were found to be irrep-

Arthroscopy, Vol. 10, No. 4, 1994

PARTIAL REPAIR OF IRREPARABLE ROTATOR CUFF TEARS 365

arable, the margins were repaired anatomically to as great an extent as possible, and a defect in the cuff was left where the retracted margins could not be anatomically repaired. The tendons torn in each case are shown in Table 2. The majority of these tears involved the supraspinatus and posterior cuff, although some extended anteriorly to involve the subscapularis. The average size of the tear was 20. I cm 2 (--4 × 5 cm).

There were minor variations in surgical technique among the five surgeons. In general, the surgery was performed in a lateral decubitus position with the patient secured by a bean bag. In this position, an arthroscopic assessment of the shoulder was performed. If the rotator cuff tear was deemed suitable for attempted repair, an open or arthroscopic acro- mioplasty was performed, depending on the prefer- ence of the surgeon. An anterolateral deltoid- splitting incision was used. A portion of the anterior deltoid could then be dissected from the acromion if needed for greater exposure. The free margin of the retracted cuff was followed anteriorly and posteriorly. In the case of a massive posterior tear, the cuff tissue sometimes was scarred down to deltoid, and careful dissection was essential to mobilize the posterior cuff. One of the authors (A.P.) used a sec- ondary posterior deltoid split to aid in mobilizing the posterior cuff. Anterior tears could be equally difficult to mobilize. The goal was to mobilize the cuff to such an extent that an anatomic repair of a portion of the cuff could be obtained, balancing the anterior and posterior cuff to restore the transverse plane force couple. The repair was typically performed by sutures to a bone trough. The superior cuff was the portion with the greatest retraction, and any remaining hole in the superior cuff after repair of the anterior or posterior cuff was left unrepaired.

A word about patient positioning for massive posterior tears is worthwhile. The lateral decubitus position allows the surgeon to visualize and surgically manipulate the posterior cuff much more easily than

TABLE 2.

Tendons torn No. of shoulders

SS 1 SS + IS 8 SS + Sub 2 SS + IS + Sub 2 SS + IS + 1/zTM 1

SS, supraspinatus; IS, infraspinatus; Sub, subscapularis; TM, teres minor.

does the supine position. In the lateral decubitus position, the lights can easily be aimed posteriorly and the instruments (e.g., dental burr) can be in- serted at a comfortable operating angle for the surgeon. In contrast, if this same posterior repair is attempted in the supine position, the lights cannot be aimed at the posterior cuff, gravity pulls the ad- jacent structures into the field, and the instruments have to be aimed uphill. For these reasons, we suggest that the repair be performed with the patient in the lateral decubitus position.

RESULTS

The tears were repaired as completely as possible. The average residual defect was 2.9 c m 2 ( - I x 3 cm) compared with an average tear size of 20.1 cm 2 ( -4 x 5 cm) before repair. In each case, the residual defect was in the superior aspect of the rotator cuff.

Active forward elevation improved from a preoperative average of 59.6 ° to a postoperative average of 150.4 ° , for an average gain of 90.8 ° (Table 3). Strength of forward flexion improved an average of 2.3 grades (0-to-5-point scale).

UCLA scores improved from a preoperative average of 9.8 to a postoperative average of 27.6. There were two excellent, six good, five fair, and one poor results. It should be noted that even those with fair results were significantly improved in terms of pain and function. Bear in mind that the preoperative UCLA scores were extremely poor. All but one patient (the poor result) expressed satisfaction with the procedure.

DISCUSSION

This study shows that partial repair of massive irreparable rotator cuff tears can produce signifi- cant functional gains. The 14 patients in this study who underwent partial repair of massive cuff tears gained an average of 90.8 ° forward elevation and an

TABLE 3. Improvement in clinical parameters (averages)

Presurgery Postsurgery Gain

Active elevation a 59.6 ° 150.4 ° 90.8 ° Strength (0 to 5 scale) 2.1 4.4 2.3 UCLA score 9.8 27.6 17.8

a Elevation denotes the plane of motion midway between the planes of shoulder abduction and shoulder flexion,



average of 2.3 grades in flexion strength (0-to-5- point scale). Flexion strength presumably improved because of the improved function of the rotator cuff, with restoration of a stable glenohumeral fulcrum for the deltoid to work against.

The functional improvement in these patients was dramatic. One must recognize that their preoperative function was extremely poor, accounting for their very low preoperative UCLA scores. Even those in the "fair" category had large improve- ments in function, and all patients except one (the poor result) were very satisfied with their results.

As a technical matter, some of the large posterior tears can be difficult to mobilize if the patient is in a supine position. The lateral decubitus position has some advantages. First, it allows for easy arthroscopic evaluation of the tear (most arthroscopists prefer the lateral decubitus position). Second, this position allows for better lighting into the posterior shoulder and easier access of instrumentation into the posterior shoulder, particularly if the surgeon's exposure is through the raphe between the anterior and middle deltoid.

The patients in this study had irreparable tears that extended anteriorly or posteriorly to such a degree that the transverse plane force couple was no longer balanced (Fig. 1). These patients had lim- ited shoulder elevation due to loss of this transverse plane force couple; as such, they possessed "dys- functional cuff tears ." Our goal was to convert them to functional cuff tears by restoring the force couples, even if we could not completely cover the hole.

A functional rotator cuff tear must satisfy five biomechanical criteria as previously defined by one of us (S.S.B.) (10):

1. Force couples must be intact in the coronal and transverse planes.

2. A stable-fulcrum kinematic pattern must exist. 3. The shoulder's "suspension bridge" must be

intact. 4. The tear must occur through a minimal surface

area. 5. The tear must possess edge stability.

The goal of our surgical repair was to satisfy these biomechanical criteria to the extent that we created a functional cuff tear. In high-demand patients with irreparable cuff tears, one should con- sider partial repair of the posterior or anterior cuff to restore the force couples, even though the superior cuff is generally too retracted to repair. This requires that the surgeon leave a hole in the top of the cuff. Anatomic dissections have shown that the rotator cable inserts anteriorly at the level of the biceps tendon (above the subscapularis) and poste- riody at the lower border of the infraspinatus (17). Therefore, a biomechanically sound posterior repair must include at least the inferior one half of the infraspinatus (Fig. 2), and a similarly sound anterior repair should include all of the subscapularis (Fig. 3). Under no circumstances should an intact subscapularis or infraspinatus be transferred superiorly to cover a hole in the cuff.

Patient selection bears special mention. The concept involves identification of those patients that have an imbalance between the subscapularis anteriorly and the infraspinatus-teres minor complex posteriorly. Physical examination will detect the muscle deficits. A patient with torn external rotators will have little if any strength with resisted external rotation. A patient with a torn subscapularis will have a positive lift-off test (18)¢ with inability

I A Uncoupling of Essential Forces IB

;;te;oL ot ,,on - \

O = Deltoid I = Infraspinatus

TM=Teres minor | r ~ ' M

FIG. 1. A: Transverse plane force couple is disrupted due to massive tear involving the posterior rotator cuff, infraspinatus (I), and teres minor (TM). B: Alternative pattern of disruption of transverse plane force couple. Transverse plane force couple is disrupted due to massive tear involving the anterior rotator cuff, subscapularis (S).



to lift the maximally internally rotated forearm off the lower lumbar area. With the aid of these two tests (resisted external rotation and the lift-off test), we can choose the ideal patients for repair and restoration of the transverse plane force couple. Such patients would have an inability to function over- head. They would also exhibit one of the following physical findings on examination: (a) positive lift- off but strong external rotators; or (b) negative (intact) lift-off but weak external rotators.

Patients in these two categories can have function

2A

FIG. 2. A: Anterior projection of a massive posterior tear shows that the subscapularis is intact. B: Posterior projection of a massive posterior tear shows that the supraspinatus, the infraspinatus, and most of the teres minor are torn. C: A satisfactory partial repair of the posterior rotator cuff must include at least the inferior half of the infraspinatus.

restored by appropriate partial rotator cuff repair to restore the transverse plane force couple. A patient could potentially have a positive lift-off result and weak external rotators, indicating a global tear involving the anterior and posterior rotator cuff. We did not encounter such a tear. However, we would advise anterior and posterior partial repair if possible.

A commonly used technique to cover a massive rotator cuff defect is tendon transposition (5-9). In this procedure, all or a part of an intact subscapu-

213

2C



3A,B

3C !!iii!i~iii~i~iiiii!iiiiiiiiiii~i~i~iiiiiiii~iii!~i~iiiiiiiiiiiiiiiiii~i~iiiii~i;i~;

FIG. 3. A: Anterior projection of a massive anterior tear shows that the supraspinatus and most of the subscapularis are torn. B: Posterior projection of a massive anterior tear demonstra tes intact infraspinatus and teres minor. C: A partial repair of a massive anterior cuff tear must completely repair the subscapularis.

laris or infraspinatus tendon is transferred superiorly to cover the hole in the cuff. However, the mechanics of the shoulder are unfavorably altered by this transfer. Ordinarily, the centroid (line of action) of the subscapularis passes inferior to the center of rotation of the humeral head. In this position, the subscapularis forms an important coronal plane

force couple with the deltoid (Fig. 4A). By transfer- ring this muscle superiorly to cover the defect in the cuff, the centroid of the transferred portion of subscapularis passes superior to the center of rotation. In this position, the moment produced by the subscapularis is in the same direction as the moment created by the deltoid, and the force couple is de-



4A

[2

4B

FIG. 4. A: The centroid (line of action) of the subscapularis lies inferior to the center of rotation of the humeral head so that the subscapularis forms a force couple with the deltoid. These two muscles have moments that are opposite in direction. B: The subscapularis in its transferred position now has its centroid above the center of rotation, and its moment is in the same direction as the deltoid moment. This muscle transfer destroys the important coronal plane force couple. D, deltoid; S, subscapularis.

stroyed (Fig. 4B). This destruction of the coronal plane force couple, which is responsible for main- taining a stable fulcrum of motion for the shoulder, can contribute to superior migration of the hu- merus.

The tissue subtended by the rotator cable is frequently a crescent of flimsy stress-shielded capsular tissue that has been found arthroscopically, at anatomic dissection (17), and in the biomechanics lab- oratory to be redundant and protected from tensile loading by the rotator cable in most elderly individuals (10). Because this rotator crescent is typically not loaded under tension, but rather is stress- shielded by an intact rotator cable, we see no reason to make heroic efforts to repair defects in the rotator crescent in elderly individuals as long as the rotator cable and the force couples have been restored.

One important conclusion to be drawn from this article is that a residual defect in the rotator cuff is not necessarily painful. Much of the previous liter- ature regarding treatment of rotator cuff tears has revolved around covering the hole (1-9), as if the hole in the cuff were the source of pain and dys- function. A recent comparison of arthroscopic debridement versus open rotator cuff repair (19) dem- onstrated equal relief of pain by either debridement or repair, although overall function was somewhat better with repair. The present study indicates that a residual hole in the cuff is not necessarily painful and that the location of the hole is the primary de- terminant of rotator cuff function. It is our opinion that we need to deemphasize the ingrained ortho- paedic tenet of obtaining a watertight closure of rotator cuff defects and instead to emphasize the im- portance of restoring the shoulder's force couples. As for the painful rotator cuff tear, the culprit may be edge instability (Fig. 5). If the tear has a thick

FIG. 5. A: Subacromial edge instability. The redundant margin of a non- re t rac ted tear can cause pain by catching under the acromion. B: Ar- ticular edge instability. The redundant articular edge can become en- trapped intraarticularly between the rotator cable and the humeral head.

5A,B

Arthroscopy, Vol. I0, No. 4, 1994


stable edge that is not subject to entrapment, then it is not likely to be painful.

We conclude that partial rotator cuff repair is in- dicated in selected individuals in whom repair of the external rotators or the subscapularis results in a biomechanically intact rotator cuff with restoration of the shoulder's essential force couples. Tendon transposition of intact rotator cuff tissue to cover a defect in the cuff is not recommended because it can adversely affect the biomechanics of the shoulder.

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2: Heikel HVA. Rupture of the rotator cuff of the shoulder. Experiences of surgical treatment. Acta Orthop Scand 1968; 39:477-92.

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5. Cofield RH. Subscapular muscle transposition for repair of chronic rotator cuff tears. Surg Gynecol Obstet 1982;154: 667-72.

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8. Neer CS II. Impingement lesions. Clin Orthop 1983;173: 70-7.

9. Neviaser R J, Neviaser TJ. Transfer of the subscapularis and teres minor for massive defects of rotator cuff. In: Bayley I, Kessel L, eds. Shoulder surgery. Berlin: Springer-Verlag, 1982:60-3.

10. Burkhart SS. Current concepts. Reconciling the paradox of rotator cuff repair versus debridement: a unified biomechanical rationale for the treatment of rotator cuff tears. Arthros- copy 1994;10:1-16.

11. Harryman DT II, Math LA, Wang KA, et al. Repairs of the rotator cuff: correlation of functional results with integrity of the cuff. J Bone Joint Surg [Am] 1991 ;73:982-9.

12. Calvert PT, Packer NP, Stoker DJ, et al. Arthrography of the shoulder after operative repair of the torn rotator cuff. J Bone Joint Surg [Br] 1986;68:147-50.

13. Burkhart SS. Fluoroscopic comparison of kinematic pat- terns in massive rotator cuff tears: a suspension bridge model. Clin Orthop 1992;284:144-52.

14. Burkhart SS. Arthroscopic treatment of massive rotator cuff tears: clinical results and biomechanicai rationale. Clin Or- thop 1991;267:45-56.

15. Burkhart SS. Arthroscopic debridement and decompression for selected rotator cuff tears: clinical results, pathomechan- ics, and patient selection based on biomechanical parameters. Orthop Clin North Am 1993;24:111-23.

16. Ellman H. Arthroscopic subacromial decompression: analy- sis of one- to three-year results. Arthroscopy 1987;3:173-81.

17. Burkhart SS, Esch JC, Jolson RS. The rotator crescent and rotator cable: an anatomic description of the shoulder 's "suspension bridge." Arthroscopy 1993;9:611--6.

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19. Ogilvie-Harris DJ, DeMazi~re A. Arthroscopic debridement versus open repair for rotator cuff tears. J Bone Joint Surg [Br] 1993;75:416-20.


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Partial repair of irreparable rotator cuff tears