Post-Instability Glenohumeral Arthritis

The Problem

Post-instability glenohumeral (GH) arthritis is a specific type of osteoarthritis affecting the GH joint. Approximately 9% of patients with shoulder arthroplasty have a history of shoulder instability and studies have shown evidence of GH arthritis in 20% of patients with a history of shoulder dislocation. Post-instability GH arthritis is referred to in different ways:

“Arthritis of instability”
“Arthritis of recurrent dislocation”
“Dislocation or capsulorrhaphy arthropathy”

There is a strong association in the literature between the development of symptomatic osteoarthritis of the GH joint and having a prior history of shoulder instability. Specific risk factors for the development of future osteoarthritis are not fully understood since patients can have GH arthritis in the setting of surgically or conservatively treated instability.

Post-instability GH arthritis occurs secondary to altered biomechanics of the shoulder articulation. In the setting of shoulder instability, eccentric loading and increased compressive loads lead to large shear forces that damage the articular surface resulting in degenerative arthritis.

Capsular Issues: Surgical repair of prior instability causes excessive anterior tightening with internal rotation contracture altering GH biomechanics. This causes the humeral head to sublux in the opposite direction of the instability (i.e. excessive anterior tightening for an anterior instability shifts the head posteriorly).
Dislocation Issues: Recurrent instability causes osteochondral damage and sheer stresses that lead to degenerative arthritis.
Hardware/Graft Damage: Metal implants or bone grafts from prior instability procedures is known to contribute to degenerative changes (i.e. impingement onto the humeral head).

These patients pose many challenges for effective treatment. Patients are typically younger compared to those with primary osteoarthritis of the GH joint. This relatively young age of affected patients may steer surgeons away from implanting a glenoid component for severe arthritic disease. Patients with post-instability GH arthritis usually have a history of multiple prior procedures to address their instability which can make subsequent surgery difficult due to scarring and altered anatomy. Bone deficiency is also commonly seen in this patient population due to recurrent instability events. The treating surgeon needs to take this into account when planning to implant a glenoid component during arthroplasty surgery

Clinical Presentation

Patients with post-instability GH arthritis present at a younger age relative to those with primary GH arthritis. The mean age at the time of shoulder arthroplasty is 49 years-old based on studies looking at this patient population.

Patients will report a history of instability often with multiple dislocation events They may or may not have had one or several prior procedures to correct the instability. The time between the last stabilization procedure and arthroplasty surgery can vary between 5 and 20 years based on longitudinal studies of these patients.

The presenting primary complaint is often moderate to severe functional disability with active shoulder range of motion including difficulty performing activities of daily living and loss of range of motion relative to the unaffected shoulder.

The history should focus on the patient’s prior treatment course. Some surgical factors that can contribute to the development of GH arthritis include:

Inappropriate diagnosis for the direction or degree of instability
Selection of a less optimal procedure for a given pathology
Intra-articular metal hardware contributing to the development of osteoarthritis
History of glenoid osteotomy
Bone block procedures that can impinge on the articular cartilage
Creation of excessive restriction to range of motion

It is important to understand how these procedures were performed by prior surgeons. How the patient’s anatomy was altered helps the surgeon identify anatomic landmarks intra-operatively and perform the correct surgical releases and/or tendon lengthening to balance the soft tissues.

Diagnostic Workup

Physical Exam

Perform a standard physical exam for evaluation of GH joint pathology. Examine the neck for cervical range of motion as well as any concurrent axial pathology involving the spine.

Examine for prior surgical incisions, which is important for the pre-operative surgical plan. Any muscular atrophy should be noted with specific attention to the rotator cuff and deltoid muscles.

Active and passive range of motion for forward elevation, external rotation, internal rotation, and cross-arm adduction should be assessed – evaluating both extremities for comparison.

With respect to instability testing – affected patients in general do not complain of instability since this pathology was previously addressed and now they have developed GH arthritis – more commonly causing stiffness than instability; however depending on the clinical situation one can perform exams to check for instability.

Load and Shift Test: Checks for any anterior or posterior instability and grades it based on the relative translation of the humeral head to the glenoid.
Sulcus Test: Checks for inferior instability by pulling on the extremity in a downward direction and checking on the lateral arm inferior to the acromion for the presence of a sulcus or empty space where the humeral head was once present.
Apprehension Exam: Checks for presence of subtle instability.

Imaging

Should include a set of plain radiographs including a true anteroposterior (AP) view of the shoulder with the humerus in both internal and external rotation – taken by turning the body 35-40 degrees toward the cassette as the scapula along with the glenoid sits obliquely on the chest wall. This brings the glenoid fossa on profile without overlap of the humeral head. The axillary radiograph is also important to evaluate the glenoid bone stock.

Common X-ray findings include posterior glenoid wear, posterior humeral head subluxation, osteophytes along the inferior humeral head, flattening of the humeral head, and metal implants showing signs of loosening/joint penetration.

A Computed Tomography (CT) Scan is the best method to evaluate glenoid bone stock. There is a need to pay close attention to the version and the bone stock in the glenoid vault.

Non–Operative Management

At least 6 months of non-operative treatment should be attempted consisting of the following:

Anti-inflammatory medications (NSAIDs) – use cautiously due to gastrointestinal side-effects
Corticosteroid injections with no more than 3 injections within 12 months
Modification of activities to decrease provoking pain
Physical Therapy – including stretching to improve range of motion and rotator cuff muscle strengthening if tolerable
Treatment should be guided by patient specific pathology and symptoms

If the arthritic disease is severe and non-operative modalities are not helpful, these measures do not need to be continued for 6 months before considering an operative intervention.

Indications for Surgery

Indications for surgical intervention include: Failure of non-operative treatment for 6 months, significant pain, and limited range of motion of the shoulder.

Challenges with surgery in patients with a history of instability include soft tissue contractures, anterior capsular contracture requiring release and tendon lengthening, and inadequate glenoid bone stock with posterior glenoid wear being most commonly seen. This can be corrected using different techniques: eccentric reaming, bone grafting, and glenoid implant augments.

If a glenoid component cannot be implanted due to poor bone stock or concern over a patient’s young age a hemiarthroplasty can be performed or consider biologic resurfacing of the glenoid using tendon or meniscal allograft.

Surgical Technique: Total Shoulder Arthroplasty

Positioning

Upper extremity block with general anesthesia is administered
Beach chair position to about 30-45 degrees incline
Perform majority of dissection with arm on a sterile padded mayo-stand
Can also use a hydraulic arm holder if surgeon prefers; this is helpful if lacking assistants

Exposure: Deltopectoral Approach

Incision from the coracoid process to deltoid insertion (2-3 cm lateral to the axillary fold)

Dissect down to the cephalic vein and make medial and lateral subcutaneous flaps

Mobilize cephalic vein and retract laterally (medial retraction is also an option)

Under the vein lies the muscular interval between the pectoralis major and deltoid muscles

Surgical Pearl

When making the initial incision and exposure ensure the shoulder is in neutral rotation

Patients with multiple prior surgeries for instability have distinction between soft tissue planes making dissection difficult due to scar and adhesions

Develop a muscular plane lateral to the coracoid process by using cautery and making the incision both distal and lateral

This helps to develop an inter-muscular plane while steering away from the medial neurovascular structures

Useful technique if the cephalic vein and deltopectoral interval cannot be identified
Develop the neuromuscular interval between the pectoralis and deltoid muscles exposing the clavipectoral fascia

Mobilize the sub-deltoid space bluntly with finger sliding along the lateral side of the humerus distally

Open the subacromial space with scissors, cob, or Darrach retractor

Incise the coracoacromial ligament just lateral to the coracoid process

Incise fascia lateral to the conjoined tendon to develop plane under the tendon for retraction

Insert Kolbel retractors underneath the deltoid and conjoined tendon to expose the subscapularis muscle
Perform biceps tenodesis (if applicable)

Be aware of prior surgeries as this may have already been performed

Find the biceps by feeling for it proximal to the pectoralis major tendon insertion

Incise the fascia overlying the biceps tendon for exposure

Pass a heavy non-absorbable suture through the tendon anchoring it to the tendon insertion of the pectoralis major

Incise the tendon proximal to its tenodesis site

Using a soft tissue clamp (Alice clamp), pull on the tendon while dissecting it proximally into the GH joint; this will also expose the bicipital grove. Excise the tendon as proximal as possible

Surgical Pearl

In patients with significant internal rotation contracture (commonly seen in the post-instability population) excision of the rotator interval maybe necessary

While dissecting the biceps tendon proximally, the surgeon should also expose and excise the capsular tissue between the supraspinatus and subscapularis tendon comprising the rotator interval

This will not only improve surgical exposure but also help in regaining external rotation for the patient

Tenotomy and Capsulotomy

Position the shoulder for tenotomy/capsulotomy (subscapularis muscle and anterior capsule)

Place the shoulder in adduction, external rotation, and extension

This produces the humeral head anteriorly and aids in identification of the subscapularis tendon insertion on the lesser tuberosity
Subscapularis and capsule are incised in one layer from a humeral-based incision starting 1-2 cm medial to the lesser tuberosity (if planning a Z-lengthening see the section below on this subject as the incisional technique is modified)

Take the incision from the top of the rotator interval to the level of the anterior circumflex vessels

Important to leave enough of a lateral cuff of tissue for closure/repair

It is difficult to separate the subscapularis from the underlying anterior capsule in patients with multiple prior shoulder surgeries

Surgical Pearl

While making the capsulotomy/tenotomy tag the tissue with a heavy non-absorbable suture for easier manipulation and retrieval later in the case

Elevate the tissue off the bone using cautery

Keep constant external rotation and adduction on the arm during this dissection

This causes the tendon/capsule unit to remain taut under tension allowing for easier elevation off the bone

Take the proximal aspect of the incision both superior and medial into the rotator interval to release more of the capsule

Dissect the capsule under and around the inferior humeral neck with an elevator and not cauterydue to the proximity of the axillary nerve

Once the humeral head is exposed remove osteophytes, especially along the humeral head and neck as these can contribute substantially to capsular contracture and limited external rotation

Remove all metal implants
Capsular Release

Use blunt finger dissection or an elevator to release scar tissue on the undersurface and the superficial aspect of the subscapularis tendon

Can elevate the subscapularis tendon along the anterior aspect of the scapular neck using an elevator

Elevate the capsule inferior and posterior around the undersurface of the humeral neck with an arm in external rotation keeping the tissues under tension (as described above)

Ensure that the coracohumeral ligament is released if not already performed
Z-lengthening

Consider Z-lengthening of the subscapularis tendon if the anterior structures are very short and contracted

Commonly used in the patients with prior Putti-Platt procedures

On exam patients will have external rotation less than neutral with arm at the side

Performing the Z-lengthening

Assess the thickness of the tendon/capsule unit

First, make a vertical incision at the undersurface of the medial musculotendinous border ensuring it is 1/3 of the full thickness in depth

Incision should span the entire length of the subscapularis muscle from inferior to superior

Can incorporate capsule in this incision

Second, make a vertical incision on the superficial aspect of the tendon at the lateral insertion, again 1/3 of the full thickness in depth

Carefully dissect within the substance of the tendon to connect these two incisions

This creates a medial flap of tendon attached to the subscapularis muscle

With the arm in external rotation release the deeper tendon and capsule off the anterior glenoid rim creating a lateral flap

Continue to mobilize the subscapularis by releasing the coracohumeral ligament, rotator interval, inferior capsule, and elevating the muscle off the anterior scapular neck as described in the prior section above

At the conclusion of the case repair the two flaps end-to-end to complete the lengthening using heavy non-absorbable suture

For every 1 cm of lengthening you gain 20 degrees of external rotation; therefore end-to-end repair may not be necessary and some overlap provides better tissue for repair

Goal is for 30-40 degrees of external rotation

Humerus Preparation

Humeral head osteotomy

Gain exposure of the humeral head using appropriate retractors (see surgical pearl section below)

Remove osteophytes from the humeral head and neck as previously described

Place the arm parallel to the floor and in 20-25 degrees of external rotation

In this position used a fixed angle guide to mark the resection level

Make osteotomy using a small oscillating saw and finish the cut with a wide flat osteotome to scoop out the resected head in one piece

Surgical Pearl

Careful retractor placement is helpful prior to humeral head osteotomy in order to protect the intact rotator cuff superiorly and the axillary nerve inferiorly

Place a small Hohmann retractor superiorly under the supraspinatus tendon for protection of the cuff tendon

Place a large Hohmann retractor inferiorly around the humeral neck for protection of the axillary nerve
Humeral implant preparation

Expose the humeral shaft by first removing the sterile mayo stand

Fully adduct and extend the arm while placing it in external rotation

Place a Darrach retractor in the space posterior to the humeral head and in line with the humeral shaft to bring the humerus more anterior

Open the humeral canal with a canal finder and begin to broach and size a humeral implant as per the specifications of the given implant manufacturer

Surgical Pearl

Once the humeral implant is properly sized and trialed the stem can be implanted

Leave the modular head components to be trialed and placed after the glenoid is finished as implanting this now will make glenoid exposure more difficult

The author’s preference is to use a press fit implant, however depending on bone quality cementing the stem is also appropriate

Glenoid Preparation

Glenoid exposure and implantation

Place the arm on the sterile padded mayo stand

Insert a large Darrach retractor along the posterior glenoid

This allows posterior retraction of the humerus while exposing the glenoid

For easier insertion of the Darrach along the posterior glenoid the arm may need to be flexed and abducted

Place a small Hohmann retractor at the 12 o’clock position of the glenoid and a curved double spike retractor anteriorly

Excise labrum and surrounding soft tissue to allow for easier glenoid preparation

Prepare the glenoid and implant component based on implant manufacturer specific techniques (reaming, component trialing, and cementing, etc.)

Surgical Pearl

If having difficulty inserting posterior glenoid retractor, abduction of the shoulder and flexion helps to place an instrument posteriorly and decreases tension from the deltoid

Further release of the inferior capsule at this point allows for improved early post-operative GH range of motion; care should be taken due to proximity of the axillary nerve

Tips for drilling central glenoid drill hole

Use finger along the anterior scapular neck to judge for glenoid version

Pay attention to location of the glenoid vault based on pre-operative CT scan which should be easily accessible during the case

Use thrombin soaked gel-foam into the peg holes for hemostasis prior to cementing and implantation of the glenoid component
Bone deficiency

Patients with history of instability typically have posterior glenoid wear and deficient bone stock

Bone loss causes insufficient seating of the glenoid component

Creates eccentric loading of the implant and increased stress at the implant-bone interface

Eccentric reaming

Creates new neutral articulation between the glenoid and humeral implants

Goal is to provide congruent contact between the bone and glenoid prosthesis by shaving down anterior bone stock to compensate for posterior losses

Things to consider:

Excessive removal may compromise bone stock to allow support for an implant

There may be residual retroversion after eccentrically reaming

Medialization of the GH joint alters biomechanics and soft tissue tensioning

Biomechanical studies show that >15 degrees of retroversion cannot be corrected by eccentric reaming alone

Bone grafting

Technically demanding procedure to perform

Indications:

Uneven wear unable to accommodate by small changes in glenoid or humeral component version

Insufficient bone stock to support glenoid component

>15 degrees of retroversion

Potential penetration of glenoid vault after version correction

Use humeral head as autograft

Resect the deficient posterior glenoid bone down to good bleeding bed

Modify the humeral head autograft to fit onto the defect and fix with a 3.5 mm cortical screw

Important to place screw so it does not interfere with glenoid implant peg fixation

Disadvantages

Graft dissolution, nonunion, fixation failure, and settling

Glenoid augmentation

Author’s preferred choice in conjunction with eccentric reaming as needed

Does not add an additional variable/layer to healing (i.e. implant-bone graft-glenoid bone stock)

Manufacturer specific, not all companies offer variable glenoid augmentation of implants so pre-operative planning is crucial
Alternatives to implanting a glenoid component

If patient is young (<40 years-of-age) and there is concern for implanting a glenoid component due to either insufficient bone stock or insufficient arthritic wear of the glenoid cartilage

Perform a hemiarthroplasty

Perform a biologic resurfacing of the glenoid using a tendon allograft

Expose glenoid and eccentrically ream as needed preserving the labrum circumferentially

Create bleeding bed for biologic graft incorporation

Place 4 double-loaded absorbable anchors into the glenoid at the 12, 3, 6, 9 o’clock positions

Prepare Achilles allograft tendon by suturing it onto itself using heavy non-absorbable suture so it is shaped similar to the glenoid (aim for 6-8 mm of thickness)

Incorporate the allograft to the glenoid by passing the suture from the anchors and securing it onto the glenoid fossa

Component Trialing

Ensure cement is fully hard for the glenoid implant before turning attention back to the humerus
Refer to manufacturer specific instructions
Use trial humeral heads to find the best fit to the proximal humerus

Assess stability with trial reduction

With GH joint reduced there should be 50-70% posterior translation when pushing the head posteriorly

Important for the humeral head to re-center itself in the glenoid by itself after it is pushed posteriorly

Closure

Repair the subscapularis and capsule as a unit using heavy non-absorbable suture

Use prior tagging sutures to find the tendon/capsule tissue for closure

Pay attention if Z-lengthening was performed and repair accordingly
Re-approximate the deltopectoral interval, subcutaneous tissue, and skin using absorbable suture

Surgical Pearl

Can use non-absorbable suture for deltopectoral interval approximation for easier identification of the interval if future revision surgery is required

Place a 10-French Hemovac drain into the joint and out of the skin at the superolateral aspect of the incision under the acromion staying clear of the axillary nerve

Remove the drain on post-operative day 1 or after it has drained less than 30 cc within 8 hours

Assess repair strength of the anterior structures in external rotation prior to full closure to guide limits of passive range of motion during early phases of therapy

The author usually limits external rotation to neutral but it can vary depending on the strength of the repair

Pearls and Pitfalls of Technique

See “Surgical Technique: Total Shoulder Arthroplasty” above for surgical pearls.

Potential Complications

Total shoulder arthroplasty in patients with post-instability GH arthritis has a higher complication rate compared to patients with primary osteoarthritis of the shoulder.

Sterling et al. showed high rate of revision

3/10 in hemiarthroplasty group

Due to development of glenoid arthritis

8/21 in total shoulder arthroplasty group

Due to (4) component failure, (2) instability, and (2) a combination of the component failure plus instability
Lehmann et al. showed a 40% complication rate (18/45)

Conservative treatment for 9/18 (50%)

5 patients with asymptomatic radiolucent lines

1 with clinical signs of instability without dislocation

3 with rotator cuff tears treated conservatively

Revision surgery needed for 9/18 (50%)

1 patient developed glenoid loosening requiring revision of glenoid component

6 cases of abrasive wear of the posterior glenoid component requiring implant exchange and posterior capsular shift

1 patient developed exostosis of the anterior glenoid requiring excision

1 patient had a broken screw from a coracoid transfer performed in conjunction with the arthroplasty procedure due to initial anterior bone loss

Post–operative Rehabilitation

Initial Post-Operative Phase

Sling immobilization

Important for patients to sleep with pillow under the arm to prevent extension of the humerus
Passive range of motion with limitations:

Forward elevation as tolerated

Abduction as tolerated

External rotation not to exceed neutral rotation or less depending on intra-operative assessment of subscapularis tendon repair with external rotation of the arm at the conclusion of the case

Weeks 1-6

Continue above regimen with stretching exercises

Weeks 6-12

Start active assisted range of motion exercises and stretching

Increase range of motion in external rotation
Can remove the sling but use if traveling outside the home to make others aware of an “injured shoulder” so that people use caution around the patient

Weeks 12 and Beyond

increase range of motion and begin strengthening exercises

Outcomes/Evidence in the Literature

Outcomes

Studies in the literature are limited to small retrospective cohorts with limited standardization between patients regarding soft tissue and bony defect management
Bigliani et al.

17 patients retrospectively reviewed with GH arthritis and history of prior procedures to correct shoulder instability

Average age at time of arthroplasty 43 years old

Average time since last surgery until arthroplasty was 15.9 years

Outcomes: based on the Neer rating system

Excellent results: 10 (59%)

Satisfactory results: 3 (18%)

Unsatisfactory results: 4 (23%)

Range of motion

FE: improved from 111° to 159°

ER: improved from -3° to 58°

IR: improved from L4 to T9
Sterling et al.

Retrospectively reviewed 31 patients with GH arthritis and prior history of instability

10 treated with hemiarthroplasty

21 treated with total shoulder arthroplasty

Average age at time of arthroplasty was 46 years old

Average time since last surgery until arthroplasty was 21 years

Outcomes

All patients reported significant pain relief as well as active external rotation and shoulder abduction

Neer rating system showed:

Excellent results: 7 (23%)

Satisfactory results: 7 (23%)

Unsatisfactory results: 17 (54%)

No difference in outcomes and range of motion between the hemiarthroplasty or total shoulder arthroplasty groups

Range of motion

Abduction: improved from 94° to 114°

ER: improved from 4° to 43°

Implant survival

97% at 2 years

86% at 5 years

61% at 10 years
Lehmann et al.

Retrospective review of 45 patients with GH arthritis and prior history of instability

35 treated with total shoulder arthroplasty

10 treated with hemiarthroplasty

Average age at time of surgery was 55.8 years and mean interval since last surgery was 5.3 years

Outcomes

Significant improvements in the following:

Constant scores (49.4 to 81.3)

Pain scores

Activities of daily living

Active range of motion

FE: 114° to 140°

Abd: 88° to 125°

ER: 31° to 44°

References

Bigliani, LU, Weinstein, DM, Glasgow, MT. “Glenohumeral arthroplasty for arthritis after instability surgery”. J Shoulder Elbow Surg. vol. 4. 1995. pp. 87-94. Cohort of 17 patients with history of shoulder instability underwent prosthetic replacement. With 3 years of follow-up 77% had satisfactory results and 23% had unsatisfactory results. Motion improved and authors describe techniques to correct anterior soft tissue contracture and posterior glenoid bone loss.)

Brophy, RH, Marx, RG. “Osteoarthrosis following shoulder instability”. Clin Sports Med. vol. 24. 2005. pp. 47-56. (A review article that explains the relationship between shoulder instability and the development of GH osteoarthritis. Diagnosis and management options are provided with a look at outcomes in the literature as well.)

Green, A, Norris, TR. “Shoulder arthroplasty for advanced glenohumeral arthritis after anterior instability repair”. J Shoulder Elbow Surg. vol. 10. 2001. pp. 539-45. (Retrospective review of 19 patients with GH arthritis and history of instability. Many of these patients had prior instability surgery in the shoulder including Bristow, Putti-Platt, Magnuson-Stack, and Bankart procedures. Patients were treated with arthroplasty. Results include a reduction in pain, improved range of motion, and functional use of the extremity. Although surgery in this patient population is technically challenging the outcomes are good and helps patients reduce pain and improve function.)

Hawkins, RK, Angelo, RL. “Glenohumeral osteoarthrosis. A late complication of the Putti-Platt repair”. J Bone Joint Surg Am. vol. 72. 1990. pp. 1193-7. (Cohort of patients that shows the long-term complications of performing the Putti-Platt procedure for patients with shoulder instability. Follow-up was obtained on 10 patients after 13.2 years and showed osteoarthrosis with severe limitation of shoulder motion. Treatment options are explained including conservative treatment and open surgical releases.)

Hill, JM, Norris, TR. “Long-term results of total shoulder arthroplasty following bone-grafting of the glenoid”. J Bone Joint Surg Am. vol. 83-A. 2001. pp. 877-83. (Patients with glenoid deficiency often have associated GH instability. The authors in this study looked at the long term results of using bone graft for glenoid bone loss during total shoulder arthroplasty procedures. Grafting of the glenoid successfully restored the glenoid version and volume in 14/17 patients.)

Krishnan, SG, Reineck, JR, Nowinski, Rj. “Humeral hemiarthroplasty with biologic resurfacing of the glenoid for glenohumeral arthritis. Surgical technique”. J Bone Joint Surg Am. vol. 90 Suppl 2 Pt 1. 2008. pp. 9-19. (This article explains the surgical technique for the biologic resurfacing of the glenoid using Achilles tendon allograft. This technique allows young patients to obtain adequate pain relief while living an active life without the worry of polyethylene wear.)

Lehmann, L, Magosch, P, Mauermann, E. “Total shoulder arthroplasty in dislocation arthropathy”. Int Orthop. vol. 34. 2010. pp. 1219-25. Retrospective review of 44 patients who underwent total shoulder arthroplasty and with a history of GH instabiilty with a follow-up of 44 months. Although functional outcomes improved there was a complication rate of 40% (18/45 patients) of which 20% underwent revision surgery (9/45 patients). Although arthroplasty provides improved functional scores and pain relief more studies are needed to see why these young patients have such high complication rates.)

MacDonald, PB, Hawkins, RJ, Fowler, PJ. “Release of the subscapularis for internal rotation contracture and pain after anterior repair for recurrent anterior dislocation of the shoulder”. J Bone Joint Surg Am. vol. 74. 1992. pp. 734-7. (Surgical description of subscapularis tendon release in 10 patients who previously underwent shoulder instability surgery and developed long-term contracture with some signs of osteoarthritis.)

Neer, CS, Morrison, DS. “Glenoid bone-grafting in total shoulder arthroplasty”. J Bone Joint Surg Am. vol. 70. 1988. pp. 1154-62. (Retrospective review of 65 patients who underwent bone grafting of the glenoid in conjunction with shoulder arthroplasty surgery. Surgical technique and outcomes are described.)

Neer, CD, Watson, KC, Stanton, FJ. “Recent experience in total shoulder replacement”. J Bone Joint Surg Am. vol. 64. 1982. pp. 319-37. (Retrospective review of a large cohort of patients who underwent total shoulder arthroplasty. Within this cohort is a subset of patients who went under this procedure with a history of shoulder instability. These patients developed a secondary osteoarthritis termed “arthritis of instability” that is described.)

Papalia, R, Osti, L, Del Buono, A. “Glenohumeral arthroplasty following stabilization for recurrent instability”. Br Med Bull. vol. 96. 2010. pp. 75-92. (Literature search was performed on patients undergoing shoulder arthroplasty with diagnosis of shoulder instability to determine whether there is a significant correlation and management options. Evidence shows that long-term patients develop GH osteoarthritis when there is a previous history of shoulder instability surgery. Strong associations with the development of shoulder arthropathy are limited to external rotation due to contracture, age at first dislocation, and follow-up length.)

Young, DC, Rockwood, CA. “Complication of a failed Bristow procedure and their management”. J Bone Joint Surg Am. vol. 73. 1991. pp. 969-81. (The authors retrospectively reviewed 40 shoulders in patients who failed a Bristow procedure. Complications following the index procedure included recurrent painful anterior instability, injury to articular cartilage, failure of bone block union, hardware loosening, neurovascular injury, and posterior instability. This article details how to manage complications of failed Bristow procedures as surgical revision requires careful technique and planning.)

Sears, BW, Johnson, PS, Ramsey, ML. “Glenoid bone loss in primary total shoulder arthroplasty: evaluation and management”. J Am Acad Orthop Surg. vol. 20. 2012. pp. 604-13. (Review article detailing the evaluation, classification, and management of glenoid bone loss in shoulder arthroplasty surgery.)

Sperling, JW, Antuna, SA, Sanchez-Sotelo, J. “Shoulder arthroplasty for arthritis after instability surgery”. J Bone Joint Surg Am. vol. 84-A. 2002. pp. 1775-81. (Retrospective review of 33 patients with long-term follow-up results of shoulder arthroplasty after instability surgery. The results, risk factors for poor outcomes, and complication rates are reviewed. Shoulder arthroplasty provides good results in this young patient population however it has a larger than normal complication rate compared to patients with primary osteoarthritis of the GH joint.)

Strauss, EJ, Roche, C, Flurin, PH, Wright, T, Zuckerman, JD. “The glenoid in shoulder arthroplasty”. J Shoulder Elbow Surg. vol. 18. 2009. pp. 819-33. (A review article that details the management of the glenoid in shoulder arthroplasty surgery. This review article summarizes the anatomy, variations in components design, mechanism for component failure, and a discussion of revision surgery for failed glenoid implantation. A discussion of management of glenoid arthritis in younger patients is also included.)

Summary

Post-instability GH arthritis is a unique problem encountered by patients with a history of prior shoulder instability and may have had one or multiple surgical procedures to correct this pathology. Altered biomechanics of the GH articulation causes eccentric loading and increased compressive loads that damage the articular surface resulting in degenerative arthritis. This condition is best treated with total shoulder arthroplasty when possible to relieve pain and provide a functional range of motion for patients who otherwise are severely disabled. This procedure comes with its own set of challenges on this patient population. Soft tissue balancing is important due to history of instability and likelihood of prior stabilization surgeries. Management of deficient glenoid bone stock needs to be taken into consideration. Overall, outcomes are not as good as shoulder arthroplasty performed in patients with primary osteoarthritis and complication rates are higher.

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