4 CLINICAL APPLICATIONS

4.1 The combined teres major and spilt pectoralis major transfer for selective reconstruction of irreparable subscapularis tears3

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A preliminary report

Ariane Gerber, MD, Jon JP Warner, MD

Investigation performed at the Harvard Shoulder Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA

4.1.1 Introduction

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Loss of subscapularis function leads almost invariably to painful dysfunction of the shoulder. Whereas excellent results with restoration of mobility and strength can be expected after direct repair of the tendon in reparable subscapularis tears 1, the outcome after surgical treatment of chronic lesions is less predictable. For chronic irreparable ruptures reconstruction tendon transfer has been recomended. None of the the proposed tendon transfers, like the trapezius transfer, the pectoralis major or the pectoralis minor transfer are able to restore the vector of the subscapularis muscle which may partly explain the variable clinical success of such procedures. 2-8

The aim of this study was to define a new surgical concept for irreparable subscapularis tears basing on the selective reconstruction of the subscapularis muscle-tendon unit with a combined teres major and split pectoralis major tendon transfer. In addition a report of the early clinical experience is presented.

4.1.2 Material and Methods

4.1.2.1 Concept of selective subscapularis reconstruction (Fig.1)

The anatomical and biomechanical data presented above were used to design a new reconstruction procedure for irreparable subscapularis tears. The cadaveric dissection showed that it is technically possible and safe to transfer the teres major to the lower part of the lesser tuberosity. Furthermore the orientation of the force vectors of the transferred teres major and of the lower subscapularis were similar. Thus the teres major transfer is a logical choice for reconstruction of the axillary part of the subscapularis.

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The reconstruction of the superior part of the subscapularis remains an unsolved problem. The vector analysis presented above suggests that the orientation of the pectoralis major transfer is similar to the subscapularis relative to the transverse plane. However the force vector orientation relative to the coronal plane remains profoundly different from that of the subscapularis, even after modification of the transfer, like the subcoracoid transfer by Resch8 or the split pectoralis major transfer by Warner.7

The patients involved in this study, all had had multiple procedures performed on their shoulder. Thus, extensive scarring of the anterior structures of the glenohumeral joint was expected. Therefore the split pectoralis major transfer by Warner was chosen for reconstruction of the upper subscapularis muscle to avoid injury to the musculocutaneous nerve.

Figure 1: Schematic representation of the transfer illustrating the principle of selective reconstruction of the subscapularis muscle. The teres major muscle is transferred to the lower lesser tuberosity whereas the sternal part of the pectoralis major is rerouted underneath its clavicular head and fixed to the upper tuberosity.

4.1.2.2 Patients

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Seven patients with a complete irreparable tear of the subscapularis were treated with a combined teres major-split pectoralis major transfer (combined TM-sPM transfer) by the author of this monography. There were 2 females and 5 males with an average age of 45 years (ranging from 34 to 65 years) at surgery.

All patients had had surgery involving the subscapularis tendon (1-6 procedures) prior the index procedure.(Table I)

TABLE I : Demographic data and history of first seven patients treated with a combined TM-sPM transfer

Case

Age at surgery

Primary Pathology

Number and Type of previous procedures prior index surgery

1

66

Instability

(1) Putti-Pate procedure (2) open subacromial decompression; (3) Total shoulder replacement

2

42

Instability

(1) Arthroscopic Bankart repair; (2) Open capsular shift

3

45

Fracture of the greater tuberosity

(1) ORIF greater tuberosity; (2) Open capsular release

4

42

Instability

(1)AC joint resection; (2)Debridement and irrigation for infection; (3)Open capsular shift; (4)Biceps tenodesis; (5) Open subacromial decompression; (6) Debridement and irrigation for infection

5

47

Rototor cuff tear

(1)Rotator cuff repair

6

34

Instability

(1) Open subacromial decompression; (2) Biceps tenodesis; (3)Iopen capsular shift

7

40

Instability

(1)Shoulder arthroscopy; (2) open Bankart repair; (3) Shoulder arthroscopy; (4) open capsular repair

4.1.2.3 Structural lesions, indication for transfer surgery (Table II)

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MRI or CT-scan was available for each patient before surgery. Two patients had an isolated irreparable subscapularis tear. In one patient there was a combined reparable supraspinatus and irreparable subscapularis tear. In the other patients both the supraspinatus and infraspinatus were deemed to be irreparable. In all but one patients the glenohumeral joint was normal without degenerative changes. One patient already had sustained total shoulder replacement arthroplasty. This and another patient two showed static anterior subluxation on the preoperative axillary view.

Although the subscapularis muscle was deemed to be irreparable based on the preoperative imaging in all shoulders, final decision for tendon transfer was taken during surgery.

TABLE II : Structural lesions

Case

Glenohumeral joint

Tear configuration°

1

Replaced, anteriorly subluxed

irreparable anterosuperior tear

2

No degenerative signs, centered

combined reparable supraspinatus tear, irreparable subscapularis tear

3

No degenerative signs, anteriorly subluxed

irreparable anterosuperior tear

4

No degenerative signs, centered

irreparable subscapularis tear

5

No degenerative signs, centered

irreparable anterosuperior tear

6

No degenerative signs, centered

irreparable subscapularis tear

7

No dgenerative signs, centered

Irreparable subscapularis tear

°The tear was considered irreparable if fatty degeneration > than grade II (according to Goutallier et al. on CT-scan (Goutallier, 1994 #1221), according to Fuchs et al. on MRI9)

4.1.2.4 Surgical technique

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Surgery was performed under a combined locoregional and general anesthesia allowing for optimal pain management and relaxation after extubation. The procedure was performed in the beach-chair position through an extended deltopectoral approach to facilitate exposure of the inferior border of the sternal part of the pectoralis major and the humeral insertion of the latissimus dorsi. First, all adhesions between the humeral head and the deltoid were released. The interval between the conjoined tendon and the pectoralis major was developed. In all cases the subcapularis tendon was retracted medially, deep underneath the conjoined tendon. The scar tissue covering the lesser tuberosity was removed and a humeral head retractor was used to displace the humeral head posteriorly and facilitate dissection. The tendon of the long head of the biceps, if still intact was invariably medially dislocated and degenerated. In these cases it was tenotomized and tenodesed to the short head of the biceps. With the humeral head pushed posteriorly the retracted tendon of the subscapularis could be identified. Braided number-2 sutures were passed through the edge of the subscapularis tendon. The anterior circumflex vessels and the axillary nerve were identified. The vessels were controlled with suture ligature and a vessel loop was placed around the nerve. To protect the axillary nerve, a Blunt Hohman retractor was placed between the nerve and the underlying scarred subscapularis muscle. The subscapularis muscle-tendon unit was released circumferentially. In all patients, the complete subscapularis was considered irreparable. Therefore no attempt was made to refix the degenerated muscle to the proximal humerus.

The detailled surgical technique has already been published by the author of this monography and designer of the transfer.10 The relevant steps of the procedure are decribed in Figures 2 to 8.

Figure 2: The pectoralis major tendon is identified at its humeral insertion. The tendon of the sternal head, which inserts to the humerus underneath the clavicular head, is carefully dissected and sharply released from the bone humerus. Number 2, braided, nonabsorbable sutures are placed through the end of the pectoralis tendon using modified Mason-Allen stiches. The sternal head of the pectoralis major muscle is dissected medially so that it can be oriented laterally and cranially. Medial dissection should not exceed 10 cm to avoid denervation of the sternal head11.

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Figure 3: After dissection the sternal head is rerouted underneath the clavicular portion of the muscle.

Figure 4: With the arm in maximal external rotation, the tendon of the latissimus dorsi ist exposed. The upper and the lower border are dissected before the tendon is released from the humerus.To allow refixation of the latissimus tendon at the end of the procedure, a 1 cm large cuff of tendon is left at the humeral shaft. The release tendon is reflected medially after 3 pairs of number 2 braided non-absorbable sutures have been placed in the tendon.

Figure 5: The plane between the latissimus dorsi and the teres major tendons is well defined laterally, closed to their humeral insertion. Medially the plane becomes less clear and dissection must be meticulous to avoid any damage to the short tendon of the teres major muscle. After exposure of the upper and lower border of the teres major muscle, the tendon is elevated subperiosteally from the humeral shaft and three sets of number 2 braided non-absorbable sutures are placed through the tendon in a modified Mason-Allen configuration.

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Figure 6: The teres major tendon is then mobilized by releasing adhesions to the latissimus dorsi. Dissection at the upper border of the teres major should be performed carefully to avoid any damage to the axillary nerve and the posterior circumflex vessels. Furthermore medial dissection between latissimus dorsi and teres major should not exceed 5 cm from the humeral end of the teres major tendon to save the main pedicle of the transfer. Usually adhesions limiting cranial mobilisation are found between the lower edge of the teres major and the latissimus dorsi and must be released. Before doing so, the surgeon should be aware of the exact location of the radial nerve and the deep brachial artery. Finally the tendon is transferred to the lower portion of the lesser tuberosity. The latissimus is repaired to the humeral shaft.

Figure 7: The lesser tuberosity and the bicipital groove are decorticated. Both transferred tendons are fixed to the lesser tuberosity using transosseous sutures. The teres major is fixed first to the lower part of the lesser tuberosity. As a rule the transfer should already be tight in neutral rotation, but still allowing 20°-30° of passive external rotation.Then the sternal head of the pectoralis major is fixed to the upper part of the lesser tuberosity with the arm held in 30° of external rotation. The rotator interval between the leading edges of the supraspinatus and the split pectoralis major transfer is closed.

Figure 8: Intraoperative view of a right shoulder after completion of the combined teres major and split major transfer. Teres major(1), sternal part of the pectoralis major(2), supraspinatus tendon(3), deltoideus(4), conjoined tendon(5), clavicular part of the pectoralis major(6).

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All patients were immobilized in a sling for 6 weeks. Passive range of motion was performed through a physical therapist 3 times a week during this time. After 6 weeks the sling was removed and active-assisted motion was started. Unrestricted active range of motion was allowed 8 weeks after surgery and strengthening 4 months postoperatively.

4.1.2.5 Evaluation

The preoperative and postoperative clinical evaluation was performed with the Constant score.12 The score is assigning 0-35 points for subjective assessment (0-15 points for pain and 0-20 points for ability to perform daily activities) and a maximum of 65 points for the objective assessment of the shoulder (0-40 points for mobility, 0-25 points for strength).

Furthermore patients were ask to rate their satisfaction in four categories (very satisfied, satisfied, unsatisfied, disappointed).

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Before surgery and at the follow-up visit an anteroposterior and a axillary view of the operated shoulder were taken in all patients. The axillary view was used to measure subluxation of the humeral head. Subluxation was defined as a shift of the center of the humeral head relative to the mid-distance of the glenoid.

To compare the postoperative outcome measures with the preoporative evaluation, the Wilcoxon test for correlated groups was used. The level of significance was set at p<0.05.

4.1.3 Results

4.1.3.1 Clinical outcome (Table III)

At a minimum follow-up period of 12 months (range, 12 to 18 months) all patients were evaluated clinically and radiographically.

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In the complete series (N = 7) the average relative Constant score increased from an 7% (range, 1 to 38) percent preoperatively to 40% (range, 4 to 76) at follow-up (p=0.0277). The average number of points assigned for pain evaluation increased from an average of 0 points (range, from 0 to 5) to 8 points( range, from 5 to15) after transfer (p=0.018). The average flexion was only 70 degrees (range, from 30 to 130) before surgery and was 90 degrees (range, from 60 to 170) at follow-up (p=0.0277).

The clinical subscapularis signs remained positive in all shoulders. However apprehension in adduction disappeared in 6 from 7 patients.

Patient satisfaction was high (3 patients very satisfied, 3 patient satisfied). One patient who had to be reoperated was disappointedThe sastisfied patients stated that they would recommend the procedure to another patient having a same problem they had.

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TABLE III: Relevant preoperative and postoperative clinical data

Case

Relative Constant score (% )°

Pain

(points)

Active forward flexion (degrees)

Apprehension

Preop

Postop

Preop

Postop

Preop

Postop

Preop

Postop

1

1

49

0

10

50

90

pos

neg

2

20

25

0

6

70

70

pos

neg

3

7

37

0

15

40

90

pos

neg

4

4

4

0

0

30

60

pos

pos

5

7

80

5

12

90

170

pos

neg

6

38

47

5

8

130

140

pos

neg

7

30

40

0

8

100

150

pos

neg

° In this series no patient was able to perform resisted painfree abduction before and after surgery. Based on the original descritpion of the score, 0 point was attributed for strength in all patients before surgery and at followup.

4.1.3.2 Radiographic outcome

No increase of asteoarthritic changes could be seen between the preoperative and postoperative evaluation. On the axillary view the humeral head was subluxed anteriorly in 2 patient s before surgery. At follow-up all humeral heads appeared centered on the axillary view. (Fig.9b)

4.1.3.3 Complications

In all cases the procedure was carried out without complications. There were no early infections or neurologic complications.

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One patient had a deep late infection and fusion was performed 1 year after the tendon transfer procedure. At the time of surgery both components of the transfer were found to be insufficient. This patient had alreadybeen operated 6 times before tendon transfer.

4.1.4 Discussion

Restoring muscle balance of the shoulder with tendon transfer to treat irreparable subscapularis or anterosuperior tears is one of the most challenging task in the surgery of the shoulder.

In Europe there is a trend towards treatment of irreparable rotator cuff tears with the implantation of a reversed replacement arthroplasty in the eldery patient. This is usually not an acceptable solution for the younger individual because longterm results with the inverse prosthesis are not known.

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Based on anatomical and biomechanical considerations, a new concept of subscapularis reconstruction was defined. Theoretically, it appears that the teres major may improve the performance of the pectoralis major transfer.

No complications related to the transfer occured in this series, confirming that the transfer of the teres major from the humeral shaft to the lesser tuberosity through a deltopectoral approach is a reliable and safe procedure.

In this series, six from seven patients were younger than 50 years and had a normal cartilage of their glenohumeral joint. The preoperative clinical situation was desperate charaterized by intolerable pain and loss of function after multiple surgeries. Therefore the transfer procedure was considered as a salvage procedure in this series. Nevertheless the early clinical results with the TM-sPM transfer were encouraging. Early pain relief occured in all case and all patients (including the one who had to be reoperated) considered pain relief as the main gain after surgery, although none of them was completely painfree.

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Although flexion increased significantly after surgery, the overall functional gain remained modest and the clinical subscapularis tests remained positive. However apprehension in external rotation with the arm at the side disappeared in six from seven cases and facilitated activity of daily living (Fig 9a).

Figure 9a: Clinical outcome (18 months postoperatively) of 65 years old women treated for irreparable anterosuperior tear after total shoulder arthroplasty with total shoulder revision and TM-sPM transfer. Before surgery she had a painful pseudoparalysis of the right arm.

Due to its orientation and position at the calcar of the proximal humerus, the teres major may play role as stabilizator of the joint sustaining the humeral head like hammock and pulling it backwards (Fig.9b). Investigation of muscle activity with electromyography will be required to evaluate the function of the teres major transfer as a joint stabilizer.

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Figure 9 b: The preoperative axillary view of the shoulder of patient of Figure 9a shows a clear anterior subluxation of the prosthetic head (upper picture). After revision of the prosthesis and TM-sPM transfer the shoulder is centered (lower picture).

The comparision of these results with other studies is difficult. The patient population considered here is highly inhomogenous . Furthermore 5 from 7 patients had combined anterosuperior tears. Finally all patients had had multiple surgeries before the index procedure.

Although the series presented is very small, the combined TM-sPM transfer appears to be a valuable and a safe alternative to treat irreparable subscapularis tears. The early promising subjective and objective results presented here encourage for further investigation.

4.1.5 References

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1. Gerber C, Hersche O, Farron A. Isolated rupture of the subscapularis tendon. J Bone Joint Surg Am 1996 ;78:1015 -23.

2. Mikasa M. Trapezius transfer for global tear of the rotator cuff. In: J B, RP W, eds. Surgery of the Shoulder. Philadelphia: Decker, 1984:104-12.

3. Galatz LM, Connor PM, Calfee RP, Hsu JC, Yamaguchi K. Pectoralis major transfer for anterior-superior subluxation in massive rotator cuff insufficiency. J Shoulder Elbow Surg 2003 ;12:1 -5.

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4. Vidil A, Augereau B. Transfer of the clavicular portion of the pectoralis major muscle in the treatment of irreparable tears of the subscapularis muscle. Rev Chir Orthop Reparatrice Appar Mot 2000 ;86:835 -43.

5. Wirth MA, Rockwood CA, Jr. Operative treatment of irreparable rupture of the subscapularis. J Bone Joint Surg Am 1997 ;79:722 -31.

6. Jost B, Puskas GJ, Lustenberger A, Gerber C. Outcome of Pectoralis Major Transfer for the Treatment of Irreparable Subscapularis Tears. J Bone Joint Surg Am 2003 ;85:1944 -51.

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7. Warner JJ. Management of massive irreparable rotator cuff tears: the role of tendon transfer. Instr Course Lect 2001 ;50:63 -71.

8. Resch H, Povacz P, Ritter E, Matschi W. Transfer of the pectoralis major muscle for the treatment of irreparable rupture of the subscapularis tendon. J Bone Joint Surg Am 2000 ;82

:372-82.

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9. Fuchs B, Weishaupt D, Zanetti M, Hodler J, Gerber C. Fatty degeneration of the muscles of the rotator cuff: assesment by computed tomography versus magnetic resonance imaging. J Shoulder Elbow Surg 1999 ;8:599 -605.

10. Gerber A, Clavert P, Millett P, Holovacs T, Warner J. Split Pectoralis Major and Teres Major Tendon Transfers for Reconstruction of Irreparable Tears of the Subscapularis. Techniques in Shoulder and Elbow Surgery 2004 ;5:5 -12.

11. Connor P, Yamaguchi K, Manifold S, Pollock R, Flatow E, Bigliani L. Split pectoralis major transfer for serratus anterior palsy. Clin Orthop 1997 ;341:134 -42.

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12. Constant CR, Murley AH. A clinical method of functional assessment of the shoulder. Clin Orthop 1987 ;214:160 -4.


Footnotes and Endnotes

3  Submitted to J. Shoulder Elbow Surg.



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