Abstract
Background
Rupture of the pectoralis major muscle (PMM) is an uncommon injury that occurs during physical exercise and high-impact contact sports; it may result in pain, weakness, and disability. Surgical repair is currently the preferred treatment of PMM rupture. Our study assesses subjective and functional outcomes of patients following repair of acute and chronic PMM ruptures.
Methods
Retrospective review identified twenty patients who underwent PMM repair by the senior author (BRW) between 2003 and 2011. Injury and surgical data was reviewed for all 20 patients. Six patients were assessed minimum 1-year post operatively for clinical outcomes, (SF-36, DASH, and ASES), physical exam (ROM & cosmesis), and Cybex isokinetic strength testing.
Results
All patients were men with an average age of 30 years (range 20-55) at time of injury. The average time from injury to surgical repair was 3.8 months (range <1-28months), and average follow up was 16.5 months (range 0-99). The majority of patients suffered injury while bench pressing (12/20; 60%) or wrestling (3/20; 15%). The most common intra-operative findings were partial sternal tears (9/20; 45%) followed by complete sternal tears (4/20; 20%). Six (30%) of twenty patients consented for on-site follow-up and clinical assessment. Average preoperative physical component scores from SF-36 improved from 43 (range 37.8-52.7) to 53.1 (range 48.1-55.8) at follow up. Average preoperative DASH scores decreased from 74 points (range 68.7-83.3) to 5.3 points (range 1.7-8.3) at follow-up. Average pre-operative ASES scores improved from 82.8 points (range 71.7-96.7) to 96.7 points (range 91.7-98.3) at follow up. Average isokinetic strength deficiency in horizontal adduction at 60°/s was 15% (range 16%–29%) and average at 120°/s was 9% (range 2%–21%). According to the Bak criteria, overall results were excellent in two patients (33%), good in two (33%), while two (33%) had a fair result.
Conclusion
Surgical repair of PMM rupture by suture anchor fixation provides high patient satisfaction and predictable return of strength, cosmesis, and overall function. Suture anchor fixation produced similar clinical outcomes and return of strength when compared to other surgical repair methods. Our results demonstrate isokinetic strength deficiency similar to historical results.
Level of Evidence
Level 4: Retrospective Case Series
Introduction
Rupture of the pectoralis major muscle (PMM) is an uncommon injury. There are less than 400 reported cases in the literature. Injuries typically occur during strenuous exercise and high-impact sports. As participation in these activities increases, the incidence of PMM ruptures has increased as well1. Rupture or avulsion of the pectoralis major can lead to pain, weakness, and disability, especially in athletically active persons. Clinical presentations include ecchymosis, swelling, and asymmetric webbing of the axillary fold2. Surgical repair is currently the preferred method of treatment.
Pectoralis major muscle ruptures occur most frequently when the arm is extended and externally rotated, specifically when the pectoralis major muscle is eccentrically contracting1,2. This motion is most common while lifting weights during a bench press exercise1. Due to this mechanism of injury, it is almost exclusive to males in their 20s to 40s2. Rupture or avulsion is often associated with an audible pop, tearing sensation, and immediate pain. Musculotendinous junction and intramuscular ruptures often result from direct trauma3.
Ultrasound and MRI are often used to identify patients that would benefit most from surgical repair4,5. Operative examination of tears reveals tendon avulsion as the most common rupture type (65% frequency) followed by musculotendinous junction rupture (27% frequency)1,2. Due to the unique PMM morphology (sternocostal and clavicular muscle heads, overlapping and variable length muscle fibers), tear classification can be difficult to determine especially when considering variance in timing, location and extent of injury1,6.
While complete function of the pectoralis major muscle is not necessary for activities of daily living, repair of ruptures increase patient satisfaction, strength, cosmesis, and shortens return to competitive sports7. Prognosis is unrelated to the age of the patient or to the location of the rupture6. Surgical treatment of pectoralis major ruptures is associated with lower incidence of strength deficiency as compared to non-surgical treatments8. In particular, athletes have a better functional result after surgical treatment than after nonsurgical treatment9. Decreased strength has been associated with operative and non-operative treatment8. Most evidence suggests that surgical treatment within 8 weeks of injury provides significantly better outcome than nonsurgical treatment or delayed repair6,8.
The two main surgical treatment options for complete pectoralis major tendon rupture are transosseous sutures and suture anchors. Bone troughs, bone tunnels, screw and washers, and endobuttons are other repair options that have been used as well. All methods have excellent postoperative results, which allow surgeons to choose their preferred technique2. To date, no comparison of different surgical techniques has been published. Currently, transosseous sutures and anchor sutures are most commonly reported techniques in the literature and have both demonstrated a relatively reliable return to sports, a fast recovery, and a low complication rate10. There is no statistical difference found between the strengths of transosseous sutures and anchor sutures techniques in tests on human cadavers, both methods had comparable failure loads7.
Nonsurgical treatment consists of physical therapy after the injured arm has been immobilized for three weeks in a sling. Passive-assistive physiotherapy is performed for three weeks followed by muscle strengthening exercises for several months. Non-operative treatment is often recommended for less active patients who are having minimal pain or functional disability and for tears that occur at the musculotendinous junction or in the pectoralis muscle belly3.
The goal of this study is to assess subjective and functional outcomes of patients following repair of acute and chronic PMM ruptures by suture anchor fixation.
Methods
After IRB approval, a retrospective review identified twenty patients who underwent PMM repair by the senior author (BRW) between 2003 and 2011. All operative repairs were performed at the University of Iowa Hospitals and Clinics in Iowa City, IA.
Data on the age, sex, mechanism of injury, rupture location and type, length of time since treatment, preoperative cosmetic appearance, pre-operative exam, diagnostic studies, operative technique, involved side, and primary follow-up were obtained from hospital records. No mentions of anabolic steroids were recorded or investigated in this study.
The operative repair was performed with patients in a beach-chair position. 18/20 repairs were performed with Mitek 2.4 mm suture anchors (DePuy, Raynham, MA). The two other repairs were performed using Arthrex corkscrew anchors (Arthrex Inc. Naples, FL). Patients were kept immobilized in slings for two to three weeks, at which point they were advanced to pendulum exercises and physiotherapy. Light resistance activity was allowed starting at six weeks. Full activities were generally resumed at three to four months.
All patients were contacted to consent for follow up clinical assessment. Six of twenty (30%) patients consented for follow up and were assessed at minimum 1-year post operatively for clinical outcomes. Outcomes were evaluated using a variety of validated health surveys including Standard Form – 36 (SF-36), Disability of Arm, Shoulder and Hand (DASH), and American Shoulder and Elbow Surgeons shoulder survey (ASES). Clinical assessment by the senior author (BRW) evaluated range of motion (ROM) and cosmesis. Pectoralis major muscle strength was assessed compared to contralateral side for peak torque at 60°/s and at 120°/s in horizontal abduction and adduction using Cybex isokinetic strength testing according to the Bak criteria6. Cybex strength testing software captured torque curves and measured peak torque as patients moved through horizontal abduction and adduction. Angle of peak torque was also measured but not used as an objective outcome measurement in this study. The outcome of the treatment at follow-up was graded as excellent, good, fair, or poor, according to the Bak criteria as described in Table 16.
Table 1.
Bak Criteria
| Excellent | Good | Fair | Poor | |
|---|---|---|---|---|
| Pain | Free | Free | With activity | Persistent |
| Range of Motion | Full | Slight Decrease | Slight Decrease | Restricted |
| Cosmesis | No complaints | Minor | Minor | Unsatisfactory |
| Return to Activity | Full function | Slight impairment | Impaired | Complications |
| Strength | <10% Isokinetic loss | <20% Isokinetic loss | >20% Isokinetic loss | >20% Isokinetic loss |
Results
In our series of 20 anatomically repaired ruptures, all patients were men. Average age was 30 years (range 20–55) at time of injury, average time from injury to surgical repair was 3.8 months (range <1-28months), and average follow up time was 16.5 months (range 0–99). The majority of ruptures (13/20; 65%) were repaired acutely (<6 weeks from time of rupture). The majority of patients (12/20; 60%) suffered injury while bench pressing with the second most common injury occurring during wrestling (3/20; 15%). Other mechanisms of injury include jet skiing, fall from height, closing bolt cutters, trimming bull horns, and throwing a football. The sternal portion of the pectoralis major tendon was involved in 16/20 ruptures, 3/20 ruptures involved both sternal and clavicular heads, and 1/20 ruptures involved only the clavicular head (Table 2).
Table 2.
Combined Patient Data
| Case# | Age, y | Trauma Mechanism | Injury to Surgery, wk | Intra-Op Tear Findings | Operation Method | Follow-up, m | Resumed Activity at Follow up |
|---|---|---|---|---|---|---|---|
| 1 | 22 | Throwing Football | 6 | Complete Avulsion | Mitek suture anchors | 8 | Yes |
| 2 | 32 | Bench Press | 2 | Avulsion Sternal | Mitek suture anchors | 99 | Yes |
| 3 | 27 | Wrestling | 11 | Partial Sternal | Arthrex corkscrew anchor | 3 | Limited |
| 4 | 23 | Bench Press | 7 | Partial Sternal | Mitek suture anchors | 4 | Yes |
| 5 | 25 | Wrestling | 3 | Complete Sternal | Mitek suture anchors | 1 | No |
| 6 | 19 | Bench Press | 6 | Partial Sternal | Mitek suture anchors | 2 | Limited |
| 7 | 27 | Bench Press | 4 | Partial Musculotendinous Sternal | Mitek suture anchors | 3 | Yes |
| 8 | 34 | Bench Press | <1 | Complete Avulsion | Mitek suture anchors | 2 | Limited |
| 9 | 28 | Bench Press | 111 | Partial Sternal | Mitek suture anchors | 9 | Yes |
| 10 | 42 | Fall accident | 17 | Partial Sternal | Mitek suture anchors | 4 | Limited |
| 11 | 36 | Bench Press | 13 | Partial Sternal | Arthrex corkscrew anchor | 52 | Yes |
| 12 | 55 | Closing Bolt Cutter | 60 | Complete Avulsion | Mitek suture anchors | 43 | Yes |
| 13 | 21 | Bench Press | 2 | Complete Sternal | Mitek suture anchors | 0 | Limited |
| 14 | 29 | Jet Skiing | 4 | Partial Sternal | Mitek suture anchors | 1 | Limited |
| 15 | 22 | Wrestling | <1 | Complete Sternal | Mitek suture anchors | 45 | Yes |
| 16 | 22 | Bench Press | 1 | Partial Sternal | Mitek suture anchors | 2 | Yes |
| 17 | 52 | Trimming Bull Horn | 19 | Complete Clavicular | Mitek suture anchors | 20 | Yes |
| 18 | 20 | Bench Press | 1 | Complete Sternal | Mitek suture anchors | 17 | Yes |
| 19 | 22 | Bench Press | 1 | Partial Avulsion Sternal | Mitek suture anchors | 2 | Yes |
| 20 | 40 | Bench Press | 5 | Partial Sternal | Mitek suture anchors | 13 | Yes |
All patients who returned for follow up ≥6 months from surgery reported returning to activities of daily living (13/20: 65%). Some patients (6/20, 35%) were lost to follow up by 4 months from surgery (Table 2). One patient suffered a re-injury before his 1 month follow up and reported no return to function (Table 2). Our study was not powered to detect differences in clinical outcomes between patients with acute tears (<6 weeks between injury and repair) compared to chronic tears (>6 weeks between injury and repair)2.
Six (30%) of twenty patients consented for further clinical assessment (Table 3). Of these patients, three underwent acute repair and three had delayed repair (>6 weeks from time of injury). Both groups showed improved health outcomes postoperatively. Average preoperative physical component scores from SF-36 improved from 43.1 (range 37.8–52.7) to 53.1 (range 48.1–55.8) at follow up. Average preoperative DASH scores decreased from 73.9 points (range 68.7–83.3) to 5.3 points (range 1.7–8.3) at follow-up. Average pre-operative ASES score improved from 82.8 points (range 71.7–96.7) to 96.7 points (range 91.7–98.3) at follow up.
Table 3.
Final Outcome Six Patients
| Case | Pain free | Range of motion | Cosmetic complaints | Activity restrictions | Peak Torque 60°/s* | Peak Torque 120°/s* | Outcome | Repair Timing |
|---|---|---|---|---|---|---|---|---|
| 2 | Yes | Full | None | None | 17% | 5% | Excellent | Acute |
| 11 | Pain on exertion | Full | None | None | −29% | −21% | Fair | Delayed |
| 12 | Yes | Full | None | None | −22% | −8% | Excellent | Delayed |
| 17 | Pain on exertion | Abduction limited to 130° | None | None | −17% | −2% | Fair | Delayed |
| 18 | Yes | Full | None | None | −23% | −19% | Good | Acute |
| 20 | Yes | Internal rotation limited to 45° | None | None | −16% | −9% | Good | Acute |
Isokinetic peak torque of horizontal arm adduction of the injured arm is compared to the contralateral side and presented as a percent deficit. Physiologic variance shows <10% variance in horizontal adduction strength in un-injured individuals [2].
Two patients (33%) had minimal pain on exertion and decrease in range of motion (Table 4). No patients had cosmetic complaints. Average isokinetic strength deficiency in horizontal adduction at 60°/s was 15% (range 16%–29%) and average at 120°/s was 9% (range 2%–21%). According to the Bak criteria, overall results were excellent in two patients (33%), good in two (33%), and two (33%) had a fair result. As a group, those who underwent acute repair fared better according to the Bak criteria than those undergoing delayed repair, with one excellent and two good results compared to one excellent and two fair results, respectively.
Table 4.
Average Health Outcomes of Acute vs Delayed Repairs
| Pre-operative | Post-operative | |||||||
|---|---|---|---|---|---|---|---|---|
| SF-36 PCS | SF-36 MCS | DASH | ASES | SF-36 PCS | SF-36 MCS | DASH | ASES | |
| Acute Repair (<6 weeks) | 46.9 | 46.5 | 70.0 | 80.0 | 54.0 | 55.3 | 4.6 | 96.7 |
| Delayed Repair (>6 weeks) | 41.8 | 49.7 | 75.9 | 84.2 | 52.2 | 53.5 | 6.1 | 96.1 |
Discussion
There are a total of 365 PMM ruptures reported in the literature that occurred between 1822 2010, and 274 of them occurred in the last 20 years1. The increased number of reported injuries in the past 20 years has been attributed to increasing activity in high impact sports, competitive weight lifting, and extreme sports. Few case studies, less than 100, have reported clinical outcomes following surgical repair of the PMM using suture anchor fixation.
Pectoralis major muscle rupture is an uncommon injury that can have a positive clinical outcome if diagnosed early and surgically repaired. Unlike other injuries where a delay in surgical treatment can lead to decreased strength, range of motion, and overall function, in PMM rupture, delays in surgical treatment have not been shown to have decreased clinical outcomes when compared to acute repairs, although the repair technically is much easier in the acute setting2. More information regarding acute vs chronic repairs is needed to guide clinical decisions and provide patient education. Our study was not significantly powered to show differences between these two groups, but our study did find that patients who underwent acute repair had slightly better health outcomes and functional return according to the Bak criteria when compared to those who had delayed repairs.
The demographics of the patients in the present study are consistent with the literature, males in their 2nd to 4th decade of life. Historically patients suffer full thickness tears to the sternal head while bench pressing and our series showed similar results with the majority of tears involving only the sternal head. PMM ruptures can be difficult to classify due to the unique tendon morphology consisting of sternocostal and clavicular heads, anterior and posterior tendon layers, and variable muscle fiber length. Also, variance in presentation based on chronic-ity, location and extent of injury can complicate rupture classification1,2. Determining tear classification by MRI, ultra-sound, and intra-operative finding is essential to guiding surgical repair. Two main classification schemes exist for PMM ruptures (Tietjen and ElMaraghy), however these classifications only guide surgical management, rehabilitation, and research; there is no evidence that PMM rupture classification correlates with surgical outcomes1,13.
Our case series had several unique mechanisms of injury varying from trimming bull horns to closing bolt cutters not noted elsewhere in the literature. Of the patients who underwent further clinical follow-up, all patients reported improvements in subjective outcomes and would elect to undergo surgery again. Factors associated with decreased outcomes were limited range of motion, slight impairment with return activities, and minimal pain on exertion.
The strengths of our study include complete reporting of mechanism of injury, intra-operative tear descriptions, repair technique, and activity level at follow-up. Weaknesses of our study include small sample size and 30% follow-up at a minimum of one year for clinical assessment, which introduces the possibility of selection or survivorship bias. Our study also reports follow up data from variable points in time after surgery, which may lead to reporting bias. Ideally, all patients would have a set schedule for follow-up prior to enrollment in the study. Our patients undergoing Cybex strength testing may have suffered from Hawthorne effect while being observed performing strength testing. Lastly, our study did not evaluate study participants for anabolic steroid use, which has been associated with increased rates of tendon rupture and improved healing11.
Conclusion
Surgical repair of PMM rupture by suture anchor fixation provides high patient satisfaction and predictable return of strength, cosmesis, and overall function. Suture anchor fixation produced similar clinical outcomes and return of strength when compared to other surgical repair methods6,12.
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