Is this subscapularis reconstructable?

A 64 year old female presented with chronic right shoulder dysfunction and pain after an injury playing tennis in 2022, where she hit an overhead ball and felt a pop in her shoulder. She then had a recurrent injury in 2025 with a similar mechanism playing pickleball and was diagnosed with a rotator cuff tear. She had participated in PT and got some functionality back but remained weak, and then had a fall biking which further reduced the function of her shoulder. She complained of anterior shoulder pain and an inability to perform overhead activity due to weakness. Her exam revealed full active motion, but substantial weakness of belly press and lumbar lift-off. Passive external rotation was to 90 degrees. There was a palpable defect in the subscapularis. Plain radiographs were normal. MRI images are shown below.

In spite of our lack of optimism regarding the reconstructability of this chronic tear, the patient asked for an exploration and repair or reconstruction if possible.

At surgery the upper half of the subscapularis was detached of poor quality. With care to protect the axillary nerve, dissection of the lower half of the subscapularis was carried out  freeing it from the inferior capsule, and releasing the anterior capsule from the glenoid.

After this 360 degree release, excellent quality (> 1 cm thick) tendon with subjacent capsule could be easily approximated to the entire footprint at the lesser tuberosity. Six FiberWire sutures were passed through the lesser tuberosity and the tendon. The long head tendon of the bicep was incorporated in the repair. After securing the tendon, the shoulder externally rotated to 30 degrees with a firm endpoint. 

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Building Back

Marsh Wren reconstructing nest

Montlake Fill

2010

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link)
The total shoulder arthroplasty (see this link)
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)

Shoulder rehabilitation exercises (see this link). 

Does subscapularis sparing = subscapularis sparing?

Clinically important subscapularis failure is reported in approximately 5% of patients following anatomic total shoulder arthroplasty. For example, Functional and radiographic results of anatomic total shoulder arthroplasty in the setting of subscapularis dysfunction: 5-year outcomes analysis found that patients who develop subscapularis dysfunction after TSA have worse patient reported outcome, range of motion, functional tasks of internal rotation, and radiographic outcomes, as well as increased rates of revision. In spite of subscapularis dysfunction, these patients maintained clinically significant improvement for pain and function at a mean 5-year follow-up.

Some surgeons have advocated a "subscapularis-sparing" approach to shoulder arthroplasty, with the goal of improving patient outcomes. The theoretical advantages of the subscapularis-sparing approach include earlier rehabilitation, reduced risk of subscapularis failure, and preservation of anterior shoulder stability.  See for example, The subscapularis-sparing windowed anterior technique for total shoulder arthroplasty which reviewed 47 cases performed by an individual experienced surgeon. 

However a recent article, Safety and Efficacy of Subscapularis-Sparing Shoulder Arthroplasty Approaches: A Systematic Literature Review considered 15 studies (1573 patients) reporting subscapularis-sparing shoulder arthroplasty. Eight studies directly compared subscapularis-sparing and standard techniques. The authors concluded "subscapularis-sparing" shoulder arthroplasty is a safe and effective technique with comparable patient outcomes, range of motion, pain and revision to nonsparing techniques." - i.e. they did not find evidence of greater clinical value with the "subscapularis-sparing" approach.

Two articles directly compared the two techniques (both by the same authors):

Total shoulder arthroplasty using a subscapularis-sparing approach: A radiographic analysis concluded "Although anatomic restoration of the shoulder can be accomplished using subscapularis-sparing TSA, retained osteophytes and significant mismatch of the HHD raise concerns regarding long-term outcomes."

Subscapularis-Sparing Total Shoulder Arthroplasty: A Prospective, Double-Blinded, Randomized Clinical Trial reported "At short-term follow-up, the outcome of TSA using the SSC-sparing surgical approach was similar to the outcome of TSA using the standard approach."

Concerns

(1) Like all new techniques, subscapularis-sparing has a learning curve to be negotiated by each surgeon using it. Even in experienced hands, in certain cases the technique may need to be abandoned in favor of a subscapularis takedown. See The subscapularis-sparing windowed anterior technique for total shoulder arthroplasty. 

(2) Risk of subscapularis distruption. Ultrasound assessment after a subscapularis-sparing approach to total shoulder arthroplasty found that rate of subscapularis disruption using a subscapularis-sparing approach for aTSA by was 14% (32 (86%) of 37 were intact)- thus, the risk of tendon injury is not eliminated with the subscapularis-sparing approach. As is the case for the failures with the standard approach, those with disrupted tendons had reasonable patient-reported outcomes but demonstrated decreased strength in forward flexion, abduction, and external rotation. 

(3) Limited exposure (See The subscapularis-sparing windowed anterior technique for total shoulder arthroplasty.)

    a. Restricted visualization may result in suboptimal component positioning, with 31.8% of patients showing center-of-rotation differences >3 mm. Additionally, humeral head diameter mismatch >4 mm occurs more commonly in the subscapularis-sparing group compared to traditional approaches.

    b. Incomplete osteophyte removal occurs more frequently with the subscapularis-sparing technique, achieved in only 75% of cases compared to more complete removal with traditional approaches. 

(4) Complications

    Complication profiles were similar between subscapularis-sparing and standard approaches in the randomized trial, with 3 patients in the sparing group and 2 in the standard group requiring revision surgery. See: Subscapularis-Sparing Total Shoulder Arthroplasty: A Prospective, Double-Blinded, Randomized Clinical Trial 

[2]Incomplete osteophyte removal occurs more frequently with the subscapularis-sparing technique, achieved in only 75% of cases compared to more complete removal with traditional approaches. 

Comment:

The subscapularis-sparing approach is being explored to minimize clinically significant subscapularis dysfunction after shoulder arthroplasty. 

We have not adopted the subscapularis-sparing approach at this point; instead we prioritize surgical exposure to optimize glenoid component seating and complete osteophyte resection. We have not conducted a head to head comparison of our method to the subscapularis-sparing technique.

We also recognize that all shoulders and all subscapularis tendons are not the same.  Thus, as the protocol below emphasizes (steps 1, 2 and 3), assessing in each patient the risk factors for subscapularis failure - regardless of the technique used - is essential to surgical decision making.

As Johnathan Swift (author of Gulliver's Travels) pointed out in 1750:

Our approach for anatomic arthroplasty is based on several key steps:

(1) Assess preoperative stiffness. Shoulders with limited external rotation when the arm is adducted are at higher risk of repair failure.

(2) Assess preoperative strength. Shoulders with weak internal rotation may have poor quality subscapularis tendons increasing risk of postoperative failure.

(3) Assess other risk factors for subscapularis failure: inflammatory arthropathy, malutrition, steroid use, prior surgery

(4) In shoulders at high risk for subscapularis failure, consider a reverse rather than an anatomic total shoulder (aTSA).

(5) For patient having aTSA , release subscapularis tendon and subjacent capsule completely from lesser tuberosity, retaining capsule on the tendon's deep surface.

(6) Perform a 360 degree release of the subscapularis from the coracoid, glenoid, and inferior capsule to optimize excursion of tendon

(7) Perform glenoid arthroplasty

(8) If necessary, trial undersized humeral head component so that the lateral border of the subscapularis reaches the reattachment site at the lesser tuberosity with the arm in external rotation.

(9) Pass six FiberWire sutures through quality bone at the lesser tuberosity

(10) Insert humeral component sized per trialing (#5 above)

(11) Place additional FiberWire sutures in the rotator interval to reinforce the repair.

(12) Tie repair sutures

(13) Verify satisfactory motion before skin closure.

(14) Start assisted flexion in recovery room (note: our practice is to avoid plexus blocks for shoulder arthroplasty to allow sensory feedback during these exercises).

(15) Allow use of arm for activities with elbow at side. Gradually transition to active elevation starting at six weeks after surgery.

(16) Allow progressive increase in resistance over the first postoperaive year, making sure that 20 repetitions are easy and comfortable before adding additional weight.

Conclusion

Current evidence suggests that standard and subscapularis-sparing approaches produce similar outcomes. We prefer subscapularis peel and secure repair because in our hands it provides excellent exposure for osteophyte resection and glenoid component positioning and seating. At the same time we recognize that other surgeons may be equally comfortable with the subscapularis-sparing approach.

Making Choices

Cliff Swallows

Kalaloch Lodge, Washington

2021

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link)
The total shoulder arthroplasty (see this link)
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)

Shoulder rehabilitation exercises (see this link). 

Updated: Anatomic shoulder arthroplasty: the subscapularis at risk

The surgical exposure of the joint for anatomic shoulder arthroplasty almost always requires subscapularis tenotomy (A) or detachment of the subscapularis tendon from the humerus using a peel (B) or a lesser tuberosity osteotomy (C). 

At the conclusion of the procedure the tendon is repaired securely

The subscapularis reattachment can be reinforced by a plication of the rotator interval (arrow).

Surgical repair of the subscapularis cannot duplicate the robustness of the complex two-layer normal subscapularis insertion. The deep layer is composed of parallel longitudinal collagen fibers inserting onto the lesser tuberosity flush with the cartilage. The superficial layer is thicker and composed of interdigitated collagen bundles inserting onto the lesser and the greater tuberosity after splitting into two bands, one lining the floor of the bicipital groove, and the other extending over the long head of the biceps tendon across the groove; see Tendons, ligaments, and capsule of the rotator cuff. Gross and microscopic anatomy

and Histologic characteristics of the subscapularis tendon from muscle to bone: reference to subscapularis lesions

In that glenohumeral arthritis is usually associated with a prolonged period of preoperative shoulder stiffness and disuse, many patients can be expected to have abnormal subscapularis structure and function at the time of joint replacement.

For the reasons stated above, it is not surprising that many patients fail to regain normal subscapularis function after shoulder arthoplasty (see The return of subscapularis strength aftershoulder arthroplasty).

For the first few months after surgery, the application of passive and active loads to the subscapularis repair can cause its failure. Thus it is recommended that the exercises shown below are avoided for this period.

Even after the first few months, certain exercises put the subscapularis at - perhaps unexpected - risk. 

To help see why, consider our high school physics lesson in equilibrium: 

force 1 times moment arm 1 = force 2 times moment arm 2

In the "fly" shown below,  the subscapularis is subjected to substantially greater loads than the force applied by the hand.

This is because the moment arm for the hand force is many times the moment arm of the subscapularis load opposing it.

Even with the commonly prescribed external rotation stretch, the hand force moment is many times the subscapularis load moment, magnifying the load on the subscapularis tendon

Muscular individuals may be especially at risk for early post operative subscapularis failure because seemingly minor events or accidents may produce enough force to damage the repair.

A recent article, Functional and Radiographic Results of Anatomic Total Shoulder Arthroplasty in the Setting of Subscapularis Dysfunction: 5-year Outcomes Analysis  identified 668 patients having two year followup after anatomic total shoulder arthroplasty; the subscapularis was managed with either a peel or a lesser tuberosity osteotomy. Postoperatively, the patients were placed in a sling for six weeks with pendulum exercises three times per day.

34 of these patients (5%) demonstrated subscapularis dysfunction as manifested by the inability to hold the hand on the belly while the elbow was placed anterior to the plane of the body. 

Notably this physical examination test was used rather than ultrasound, MRI or contrast CT, each of which can be difficult to interpret after shoulder arthroplasty because of the metal artifact.

In comparison to those without subscapularis dysfunction, patients with subscapularis dysfunction demonstrated worse postoperative Simple Shoulder Test, SANE, VAS Function, VAS Pain, and ASES scores, as well as lower rates of satisfaction and worse active range of motion. Only 47% of the patients could reach the small of their back compared to 85% with normal subscapularis function.

Patients with subscapularis dysfunction had higher rates of anterior subluxation (see example below) 

as well as higher rates of revision. 

In spite of the poorer outcomes in patients with subscapularis dysfunction, most of these patients were improved in comparison to their preoperative status. 

Notably, when subscapularis failure was suspected during the early postoperative period, the authors did not immediately recommend revision surgery, rather waiting to see if function and comfort will improve. 

Comment: It can be concluded that (a) a robust subscapularis repair and (b) protection of the repair during healing are of great importance to assure the optimal outcome from anatomic arthroplasty.

Re-repair is a consideration if there is evidence of tendon failure, especially if there has been a sudden event soon after arthroplasty. The authors of Clinically significant subscapularis failure after anatomic shoulder arthroplasty: is it worth repairing? compared minimum 1 year results with subscapularis failure after anatomic arthroplasty having subscapularis re-repairs to those having conversion to reverse total shoulder. Patients having re-repair were significantly younger than patients who underwent revision to reverse shoulder arthroplasty (mean age, 59.3 years vs. 70.3 years, had a better comorbidity profile, and had a more acute presentation (mean time between injury and surgery, 9.1 weeks vs. 28.5 weeks. 

Patients who underwent subscapularis re-repair also had a significantly higher reoperation rate (52.9% vs. 0.0%); this is expected in that older patients are unlikely to want or have a revision of a reverse total shoulder within the first year after the procedure, whereas younger patients having an attempted re-repair may consider another surgery. It is apparent that re-repair of a failed subscapularis is more likely to fail than the original repair performed at shoulder arthroplasty because the diagnosis is often delayed and the quality of the tissue is poorer.

At final follow-up, functional outcomes scores and patient satisfaction rates were not significantly different between treatment groups.

The biggest challenge lies in the management of the young strong patient having subscapularis failure after anatomic total or ream and run arthroplasty. These patients are often in their 30s or 40s and want to avoid conversion to a reverse total shoulder because of their young age and activity expectations.

In these cases, reinforcing the repair with a tendon graft becomes a consideration (see The subscapularis: anatomy, failure and reconstruction and The subscapularis).

Thanks to Mihir Sheth, UW shoulder fellow, for his help in preparing this post.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter (X): https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).

The subscapularis - anatomy, failure and reconstruction

An active man developed glenohumeral arthritis after a prior stabilization procedure on his right shoulder. He elected a ream and run arthroplasty.




His initial rehabilitation went very well, with excellent range of motion and return to all activities including cross country skiing and light weights at five months after surgery. Around that time a well-meaning relative suggested dumbbell curls with the arm adducted. However, these were associated with increased range of external rotation and pain at the subscapularis insertion on active internal rotation.




He had an incident in which he was pulling on his stockings up and felt a sudden sharp severe pain in the shoulder that radiated down to his fingers. Since that episode, he had persistent instability of the right shoulder and feelings that it slides out to the front. If he put his right hand in front of the right shoulder and pushed in, the sensation improved.

On examination he had external rotation to 90 degrees



and weakness of internal rotation.




A metal subtraction MRI was inconclusive about the status of the subscapularis tendon.





He declined a reverse total shoulder and instead elected to proceed with exploration of the shoulder and a plan for subscapularis reconstruction. At surgery the upper subscapularis tendon was torn from the repair site at the lesser tuberosity as if it had been unzipped from top down.





The glenoid had healed over with smooth fibrocartilage.





The subscapularis reconstuction was accompliashed using a braided hamstring allograft passed through drill holes in the lesser tuberosity







and then through the subscapularis medially.






The free ends of the graft were then secured to the humerus.



The shoulder was immobilized for two months, followed by a careful rehabilitation program avoiding stressing the subscapularis by passive external rotation or active internal rotation.


He recently reported: "Good morning. Everything is going very well. We arrived at Whistler yesterday for a ski week. I happily celebrated my one year anniversary following our second surgery. I continue to do my shoulder exercises on a regular basis using 10 pound hand weights for press ups while sitting for 30 to 40 reps, 12 pound weights for press ups while supine for 30 to 35 reps, 15 pound weight lift from floor while kneeling on chair for 30 reps, isometrics, band stretch. I continue to do the pulldown bar with 55 pounds for 30 reps. I use a bench type device where I sit and pull 55 pound weight for 30 reps. I do a few reps using the 70 pound weight. As far as skiing goes, I have no shoulder pain at all with either cross country skiing or downhill skiing. So as far as I’m concerned, I’m cured."


This case points to the importance of both careful repair of the subscapularis at shoulder arthroplasty


with particular attention to the suture at the superior part of the tendon





and considering reinforcing the repair with sutures in the rotator interval.





It is of interest that the load on the subscapularis is not evenly distributed along the superior-inferior extent of the tendon. The authors of Subscapularis tendon loading during activities of daily living used a computer model to estimate the relative amount of load transmitted through the superior portion of the subscapularis during activities of daily living as compared to the load that is transmitted through the middle and inferior portions.

The model indicated that the maximum force produced by the entire subscapularis muscle for the various activities ranged from 3N (reaching to opposite axilla, eating with hand to mouth) to 43 N (reaching back of head, lifting a block to head height).The superior band bore the largest percentage of the total load of the muscle (95% ± 2%). The chart below shows the distribution of load during 10 different activities.






It is evident that the superior aspect of the subscapularis is most important. This is consistent with the disproportionately large 'footprint' for the insertion of the upper subscapularis into the lesser tuberosity of the humerus (see below)





and by the beefy 'upper rolled border' of the tendon shown as "SC" in this figure from the classic work by Clark and Harryman Tendons, Ligaments, and Capsule of the Rotator Cuff





in this cadaver dissection (blue arrow)




and in this arthroscopic image (see SSc)




While this is the strongest part of the tendon, it is also sees the greatest load, so that tears of the subscapularis tendon typically start there.

The disproportionate loading of the upper subscapularis was also demonstrated by one of our residents, Vinko Zlomislic (now on faculty at UC San Diego), who did a laboratory study demonstrating that the site of repair and arm position affect suture tension in subscapularis repair.

The subscapularis tendon was incised from the lesser tuberosity in 11 fresh-frozen human cadavers. A four-strand suture repair was performed to each of the two sites: (1) the lesser tuberosity (LT) and (2) the humeral neck (HN).

After each repair, the humerus was placed in four different positions (0, 30, 60, 90 degrees) of abduction with the arm in neutral rotation with respect to the plane of the scapula. In each position, a total load of 40 N was applied to the repaired tendon in the direction of action of the subscapularis.









The proportion of the total tension in each suture was determined for each repair site (LT & HN) and for each position of abduction.

With the arm in low angles of abduction, the superior suture (blue in the graphs below) experienced the greatest proportion of the overall tension in the subscapularis in comparison to the mid-superior (red), mid-inferior (yellow) or inferior (purple) sutures. The proportion of the load carried by the superior suture became less as the shoulder was abducted.








The authors concluded that the position of abduction had a profound effect on the tension in the different sutures of the subscapularis repair. Tension was concentrated at the superior suture, particularly in low angles of abduction. This may increase the risk of subscapularis failure at this critical aspect of the repair site. This is an important study in that it pointed out that all sutures of a subscapularis repair do not share equally in the load and that the amount of abduction changes the load distribution among the sutures.

The authors of Tears of the Subscapularis Tendon: A Critical Analysis Review found the tendon footprint to be broad proximally (a tendinous insertion) and tapered distally (a muscular insertion) along with a number of anatomic insertions that are separate from the main tendinous attachment. These include a medial capsuloligamentous insertion, a inferior musculocapsular insertion, a “lateral hood”, and a superior “tendinous slip,” which is attached to the fovea capitis of the humerus and con- tributes to biceps stability. Once more they found that the majority of tears of the subscapularis tendon begin at the articular surface of the superior insertion of the tendon and extend inferiorly.

Comment: It is concluded that the upper aspect of the subscapularis insertion to the lesser tuberosity is disproportionally important. After arthroplasty it needs to be carefully repaired and protected from loading while it is healing. 

Stretching in flexion does not challenge the upper aspect of the subscapularis repair.

By contrast, stretching in external rotation with the elbow at the side disproportionally loads the critical attachment of the upper subscapularis.

as do falls

and unexpected jerks on the arm.

If the subscapularis should fail after shoulder arthroplasty, consideration can be given to reinforcing the repair with a braided hamstring graft.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).