Treatment of Deltoid Contracture in Adults by Distal Release of the Deltoid

Abstract

Twenty-five consecutive adult patients (32 shoulders) with deltoid contracture were treated with distal release and followed up for an average of 4 years (range, 2-8 years). All shoulders achieved full range of motion and complete relief of pain and deformity after 3 months. No muscle weakness was clinically evident. In addition, another five adult patients (nine shoulders) with deltoid contracture were treated with distal release and quantitative measurement of muscle power recovery around the shoulder with Cybex 340 dynamometer before surgery, and 3 months and 1 year after surgery. Isokinetic peak torque of shoulder muscles did not decrease significantly at either 60° per second or 180° per second angular velocity after surgery. In addition, the shoulder extensors showed a twofold increase of isokinetic peak torque after surgical release of deltoid contracture. Distal release was a simple and effective surgical technique to treat deltoid contracture in adults. All patients in this series achieved a satisfactory outcome.

Contracture of the deltoid muscle is an uncommon disorder, and its pathogenesis has been well studied. The pathologic examination shows a fibrous band to be the main cause of the contracture, and surgical release has been considered the treatment of choice.^3,5,19,20,23 However, the method of approach has not been well defined.¹⁵ A large transverse proximal release has the disadvantages of keloid formation, wound dehiscence, and prohibition of immediate postoperative rehabilitation.¹⁷ A longitudinal proximal release usually is unable to release completely all contracture bands, and multiple skin incisions must be done that sequentially may produce skin edge necrosis. Because the deltoid muscle has three proximal origins and only one distal insertion,¹¹ a surgical technique of distal release for total correction of more severe deltoid contracture was designed.

Distal release of the deltoid insertion for treatment of contracture of the deltoid has been used for several years at the authors' institution with satisfactory results. Biomechanical testing in a limited number of subjects has shown that deltoid power is not adversely affected. The current report indicates that distal release of the deltoid insertion is a reliable and effective technique for treatment of this uncommon disorder.

MATERIALS AND METHODS

From January 1985 to December 1991, 25 consecutive adult patients (32 shoulders) who sustained deltoid contracture were treated with distal release at the authors' institution. Patient ages ranged from 25 to 65 years (average, 42 years), with a male to female ratio of 2:3. The clinical features of deltoid contracture included aching shoulder pain (100%), inability to close the axillary space (glenohumeral abduction contracture, 100%), restriction of shoulder adduction in the horizontal plane (100%), deltoid atrophy or skin dimpling (95%), and winging of the scapula (50%) (Fig 1A). The shoulder pain was not radicular and was not affected by movement of the neck but was exacerbated by attempted adduction. Patients could not move their arms freely anteromedially to palpate the opposite shoulder (Fig 1B). The length of the primary complaints varied from 3 months to 2 years. Twenty-three (92%) patients had a history of frequent deltoid injections, and two patients had associated gluteus maximus contracture.

Fig 1A: B. (A) A 60-year-old woman sustained abduction contractures of both shoulders. Winged scapulae and atrophy of the deltoid muscles also were seen. (B) The lateral picture showed that she could not move her arm across her chest to palpate the opposite shoulder because of extensive deltoid contracture.

The indications for distal release were unrelieved shoulder pain or abduction contracture of the shoulder greater than 25°,⁷ which was caused by two heads or extensive contracture of the three proximal origins of the deltoid muscle.

The contracture of deltoid muscle was divided into anterior, intermediate, or posterior part involvement. To judge the involved part, skin dimpling, muscle atrophy, and limitation of shoulder adduction combined either with flexion, neutral position, or extension of the arm were investigated. Two (middle and posterior) parts of the deltoid were involved in 29 shoulders, and extensive contracture was present in three shoulders. A one-part deltoid contracture usually was treated by one longitudinal proximal release and two-part or three-part deltoid contractures by a distal release.

Surgical Technique

Under general intubation anesthesia, the patient was placed in the lateral decubitus position. The affected shoulder was on the upside and was draped freely. A 5-cm longitudinal skin incision just over the deltoid tubercle of the humerus was made. The skin was retracted, and the insertion of the deltoid muscle was identified. The deltoid insertion then was cut and stripped subperiosteally. Any contracted band around the deltoid insertion also was released using electrocautery. Normal muscle fiber was preserved as much as possible. The arm was manipulated until full adduction with the arm at any position was achieved. Finally, the subcutaneous tissue was approximated with absorbable suture and the skin with nonabsorbable suture. No drain was inserted.

After surgery patients were permitted to move the shoulder immediately. Forced adduction of the arm was encouraged. The patients were followed up regularly. Evaluation of the wound, shoulder pain, abduction contracture, and shoulder muscle power with manual resistance test were done (Table 1).

TABLE 1: Preoperative and Postoperative Data for 25 Patients

From August 1993 to July 1994, five patients (four women and one man, from 22 to 62 years of age) with nine shoulders that were treated with distal release were evaluated prospectively for shoulder muscle power recovery (Table 2). The evaluation was done before surgery and 3 months and 1 year after surgery using a Cybex 340 dynamometer (Lumex, Ronkonkoma, NY) for testing maximal isokinetic muscle torques at adduction or abduction, flexion or extension, and internal or external rotation. Two different angular velocity tests of 60° per second and 180° per second were used concomitantly.

TABLE 2: Preoperative and Postoperative Data for Another Five Patients

The muscle torques were divided by the patient's individual body weight to get relative muscle torque. The mean of relative muscle torques in nine shoulders was compared at different periods to evaluate the recovery of muscle power. Paired t test was used to evaluate the statistical difference, and a p value less than 0.05 was considered statistically significant.

RESULTS

All 25 patients (32 shoulders) who were followed up only clinically had an average followup of 4 years (range, 2-8 years). The surgical results were assessed by pain, function, and abduction contracture of shoulders (Table 3). All shoulders achieved a full range of motion (ROM) and complete relief of shoulder pain within 3 months. The angle of abduction contracture before surgery ranged from 25° to 40° from the trunk (mean, 32°). After surgery, the abduction contracture disappeared completely in all shoulders (Fig 2). Before surgery, all patients needed frequent medication for shoulder pain, and after surgery shoulder pain subsided dramatically and completely. No additional medication was necessary. There was no subjective weakness of the shoulder muscle observed during daily activities. There was no muscle power decrease seen with manual testing in all patients. All patients returned to the same or equivalent work. There was no recurrence of their deformity. All of the patients were satisfied with the surgery.

TABLE 3: Shoulder Scoring System

Fig 2: Photograph of the same patient shown in Figure 1. After distal release, the abduction contracture and winged scapulae had disappeared.

Intramuscular hematomas were seen in two (6%) shoulders and were absorbed spontaneously within 1 month. No wound infection, wound dehiscence, or keloid formation was observed.

The recovery of shoulder muscle power in five patients evaluated by Cybex 340 dynamometer was studied completely. The relative maximal muscle torque did not decrease significantly with low or high angular velocity 3 months or 1 year after surgery. It increased significantly 200% at arm extension for both angular velocity tests (p = 0.038). As for adduction or abduction, the relative maximal muscle torque could not be measured at high angular velocity (Table 4).

TABLE 4: Relative Maximal Muscle Torque (ft-lb Per lb of Body Weight) Changes in Nine Shoulders With Low- and High-Angular Velocities

DISCUSSION

Because contracture of the deltoid muscle is an uncommon disorder, few articles report a large series of cases.^{3,14,16,19,20,23,24,26} In children, the causes are more likely from congenital abnormalities,^3,9,10,21 developmental defects,²⁷ or repeated intramuscular injections.^2,4,17,18,23 In adults, intramuscular injection is the only cause.^12,18,23 Clinically, repeated intramuscular injections are common in people but are relatively rare in patients with muscular fibrosis.^1,3 Abnormal control of collagen formation has been advocated as a possible predisposing factor.^6,13,22,25

The anatomy of the deltoid muscle with its neurovascular supply has been described.¹¹ It has three origins on the clavicle, acromion, and scapular spine but only one insertion on the deltoid tubercle of the humerus. The main action of the deltoid muscle is abduction of the arm; however, the anterior fibers assist in flexion and internal rotation, and the posterior fibers help in extending and rotating the arm externally. The axillary nerve and posterior circumflex humeral vessels run through the quadrilateral space and supply the deltoid muscle from the back.

Usually, intramuscular injections are given in the middle or posterior portions to avoid injuring the cephalic vein. This causes middle or posterior portion fibrosis, which in turn causes restricted adduction and flexion (Fig 1B).^{3,14,18,26,27} When the fibrosis is severe and extensive, because of restriction of passive adduction of the glenohumeral joint, the weight of the upper extremity sometimes creates the appearance of a winged scapula (Fig 1A).^2,8,18 The abduction contracture deformity may hinder normal muscle action and often causes aching shoulder pain.^8,18

Shanmugasundaram²³ used proximal release through a 5-cm vertical incision starting from the tip of the acromion process. Originally excision of the fibrous segment was performed, but later it was found that simple transverse division of the fibrous band of the deltoid was adequate. Movements usually are regained within 3 weeks and in most cases there has been no residual deformity. Minami et al¹⁷ released the contracture through a 5- to 6-cm transverse skin incision along the acromion, posterior to the spine of the scapula. Abduction contracture of the shoulder completely disappeared after surgery in 23 of 49 (47%) shoulders. Of the 49 shoulders, muscle transfer in combination with tenotomy was necessary in 25 shoulders because a large gap occurred under the acromion. Keloid formation at the site of operation occurred in 16% of the shoulders and loss of the natural roundness of the shoulders in 30% of the patients. Distal release as done by the current authors can correct an extensive contracture with a small wound and avoid wound dehiscence, keloid formation, and loss of natural round contour of the shoulder. It also allows early rehabilitation of the shoulders.

Distal release can correct the extensive contracture with a single wound. The procedure can be performed without injuring the neurovascular bundles. The contracture band at the insertion of the deltoid muscle is released completely until full adduction of the shoulder is achieved. The muscle power of the deltoid muscle may diminish during the early postoperative stage because of wound pain. By 3 months, in the current series of patients, abduction power and function had recovered completely. In the biomechanical study, muscle torques of any actions did not decrease, but muscle torque of extension significantly increased 200%. Thus, this would indicate that the release of the deltoid contracture was satisfactory. Improved ROM and relief of shoulder pain can help to restore muscle power and allow normal daily activity.

The deltoid muscle has rich vascularity. After the contracture band is released, an intramuscular hematoma may occur. In the current series the hematoma in both patients was absorbed spontaneously. Practically, a hematoma can be prevented by thorough hemostasis with electrocautery.

Clinically, there was no evident weakness of the deltoid muscle by manual testing after distal release. To measure the muscle torque accurately, low and high angular velocity tests with the Cybex 340 dynamometer were done concomitantly. The biomechanical study also confirmed that the muscle torque in abduction with other actions of the shoulder did not decrease after surgery. Thus, the technique of distal release could correct the restriction of shoulder movement completely, and the muscle power could be preserved. Thus, it is a reliable technique for correction of deltoid contracture.

The authors successfully developed a new surgical technique to treat deltoid contracture. With the findings of the clinical and biomechanical studies, it is an excellent technique to correct this uncommon disorder.