Shoulder Arthritis/Joint Replacement Rotator cuff tears

Sunday, October 1, 2023

Primary glenohumeral arthritis: treatment with the ream and run in comparison to total shoulder arthroplasty - 10 year followup

Glenohumeral arthritis in shoulders with an intact rotator cuff is the most common indication for shoulder arthroplasty.

The safety, effectiveness and durability of anatomic arthroplasty - the ream and run (RnR) or the anatomic total shoulder (TSA) - is widely recognized.

The authors of Minimum 10-year Follow-up of Anatomic Total Shoulder Arthroplasty and Ream-and-Run Arthroplasty for Primary Glenohumeral Osteoarthritis studied the patients and the minimum 10-year outcomes for the RnR (n=34) and TSA (n=29). In this practice, the patients chose their surgical procedure after a discussion of the risks and benefits of each.

The two groups differed in a number of important preoperative characteristics. The RnR patients were significantly younger than the TSA patients (60 ± 7 vs 68 ± 8, p<0.001), predominantly male (97% vs 41%, p<0.001), and were healthier as reflected by the American Society of Anesthesiologists score (p=0.018).

Patient-assessed preoperative and postoperative function was documented by the Simple Shoulder Test (SST)

The preoperative and the postoperative SST scores were higher for the patients having the ream and run procedure than for those having total shoulders.

Total shoulder

In the TSA group, the pain score decreased from a preoperative average of 6.6 ± 2.2 to 1.2 ± 2.3 (p < 0.001), and the SST score improved from and average of 3.8 ± 2.6 to 8.9 ± 2.6 at 10-year follow-up. (p < 0.001). The percent of maximum possible improvement averaged 64%. No patient in the TSA group required reoperation; notably there were no cuff tears or glenoid loosenings.

Ream and Run

In the RnR group, the pain score decreased from a preoperative average of 6.5 ± 1.9 to 0.9 ± 1.3 (p < 0.001), while the SST score improved from and average of 5.4 ± 2.4 to 10.3 ± 2.1 at 10-year follow-up (p < 0.001). The percent of maximum possible improvement averaged 83%.

Four patients underwent single-stage exchange to another hemiarthroplasty because of painful stiffness. Two of these 4 patients had positive cultures for Cutibacterium. One patient required manipulation under anesthesia. No patients had conversion to a TSA or reverse total shoulder.

At followup, a larger percentage of RnR patients could perform high-level shoulder functions: SST questions 7, 8, 9, 10, and 12.

As an example, a 15-year post RnR followup x-ray of the shoulder shown at the beginning of this post is shown below. Note the stable humeral fixation and the seating of the humeral head centered in the healed glenoid concavity.

This patient (now 71 years old) continues to use his arm for heavy physical work and recreation. He has excellent range of motion, comfort and function and now returns for an RnR on his opposite shoulder.

Comment: Patients with glenohumeral osteoarthritis and their surgeons have the choice of the ream and run and anatomic total shoulder. This is one of the few long term studies of the patients having each of the procedures. It is notable that young, healthy, male patients preferred the ream and run procedure after a discussion of the pros and cons of each. The RnR patients had higher levels of function both before and after surgery - particularly for the more demanding activities assessed by the Simple Shoulder Test.

As is necessary for all clinical outcome studies, this article reported the number of patients enrolled in the database and the number and reasons groups of patients were not included in the final analysis. This is the standard "Figure 1", which seems absent in many reports.

This figure shows the challenge in achieving long term followup on a high percentage of patients.

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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).

Saturday, September 30, 2023

Coming of age as a shoulder surgeon

Thanks to Dr. Scott Sigman for this podcast.

https://www.youtube.com/watch?v=Jmo94BOB2lM

The ream and run - the shoulder joint replacement for active individuals.

The ream and run shoulder arthroplasty is an established shoulder replacement procedure for active individuals with disabling shoulder arthritis (see this link). In this procedure the rough arthritic joint surface of the humerus is replaced with a securely fixed, smooth metal implant, while the irregular arthritic glenoid socket is conservatively reamed to a smooth concavity (see this link).

This procedure is an option for active individuals who wish to avoid the risks and limitations associated with the plastic socket used in conventional total shoulder replacement. It is useful in addressing severe arthritis in the shoulders of young individuals, including those having failed prior shoulder surgery.

Below are the preoperative x-rays from a 40 year old athlete showing displacement of the humeral head on the glenoid, severe arthritis and retained hardware from a previous operation.

As is our practice, the ream and run is performed without preoperative MRI or CT scans, preoperative 3-D planning, intraoperative navigation, augmented reality, cement, plastic, ingrowth component, or nerve block - making it a cost-effective procedure.

His postoperative x-rays are shown below

This man was vigorous in his rehabilitation. Here's his assisted motion the morning after surgery.

He pursued his dedicated rehabilitation. He shared this video at five months after surgery

Recently he reported: "16 months post ream and run and I can play basketball again. Able to shoot long range 3-pointers, dribble, make hook shots and do a chest pass with no problem. My shoulder hasn’t felt this good in 25 yrs." He kindly gave us permission to share this recent video

Results such as this do not come automatically after the ream and run, but rather result from dedicated, persistent adherence to the defined rehabilitation program (see this link). Patients must "do the work".

Patients provide frequent followup to their surgeon with videos such as those shown below for two patients in the first two weeks after their ream and run procedures (shared with their permission).

Comment: A successful outcome after a ream and run procedure depends on four things:

(1) informed selection of the right procedure for the right patient

(2) excellent surgical technique

(3) patient dedication to the rehabilitation program

(4) frequent communication between the surgeon and the patient during the recovery.

Saturday, September 23, 2023

Salvaging the failed humeral arthroplasty with humeral bone loss.

Proximal humerus bone loss is commonly encountered in revision shoulder arthroplasty. Bone loss can occur from component loosening and ensuing osteolysis, infection, as well as preoperative and intraoperative fracture. Careful preoperative assessment of the humeral anatomy can inform planning for surgical revision. Of particular importance is the quantity and quality of bone along the humeral diaphysis and metaphysis and the condition of the important soft tissue attachments, including the rotator cuff, deltoid and pectoralis major.

Humeral bone deficiencies can contribute both to instability of the joint and to instability of fixation of the revision implant.

1. Joint instability

The stability of the reverse total shoulder depends on concavity compression: the compression of the glenosphere into the concavity of the humeral liner by the deltoid and other scapulohumeral muscles.

Post-revision glenohumeral instability of the reverse total shoulder can be caused by inadequate restoration of humeral length and/or soft tissue attachments to the proximal humerus. Loss of humeral length reduces the tension in the deltoid, and thereby decreases its ability to provide the compressive force that stabilizes the joint. Compromised insertions of subscapularis, coracobrachialis, latissimus dorsi / teres major and pectoralis major can also contribute to insufficient joint compression.

2. Implant instability.

Instability of the humeral component is often manifested by inadequate rotational stability of the implant in the humerus. The non-circular cross section of the metaphyseal canal provides the best opportunity for obtaining rotational stability.

Some of the steps that are helpful in optimizing (1) the stability of the joint and (2) the stability of the humeral component in revision reverse total shoulder include

1. Assessing the quantity, quality and pathoanatomy at each level of the humeral bone.

Humeral Bone Loss in Revision Total Shoulder Arthroplasty: the Proximal Humeral Arthroplasty Revision Osseous Insufficiency (PHAROS) Classification System characterized the bone loss in three regions (epiphysis (1), metadiaphysis above the deltoid insertion (2), and diaphysis below the deltoid insertion (3)) as well as the bone quality in terms of cortical thinning of greater (A) or less than 50% (B) of the expected thickness. Epiphyseal bone loss can isolated compromise of the medial calcar (C) or greater tuberosity (G).

Some examples are shown below. The authors recommend that grade 2B and 3 bone loss be treated with allograft-prosthetic composites (APC) or a humeral replacement mega-prosthesis.

2) Determining whether residual cement is securely attached to bone and of possible use of cement-within-cement fixation of a new humeral implant

The example below shows an intact cement mantle without radiographic signs of loosening at the bone-cement interface. The revision was performed with a cement-in-cement revision and resulted in stable fixation at 4 years after surgery.

The example below shows a cement mantle fracture and radiolucency at the bone-cement interface that raises concern about the applicability of a cement-in-cement revision

3) Evaluation of the risk of infection (serum WBC, ESR, CRP, frozen sections, joint fluid for cell count, frozen sections, as well as submission of tissue explant specimens for culture). Often a course of postoperative antibiotics is used until the results of the intraoperative cultures become available.

4) Restoring humeral length to optimize soft tissue tension

One approach to restoring humeral length is to utilize contralateral films as guide to the desired humeral length as shown below.

Another approach is to determine the added length necessary to restore soft tissue tension as detailed by the authors of Revision Arthroplasty with Use of a Reverse Shoulder Prosthesis-Allograft Composite

5) Achieving secure fixation of the implant to healthy host bone, such as purchase in a length of healthy diaphysis exceeding two cortical diameters (see Evaluation and treatment of postoperative periprosthetic humeral fragility fractures)

6) Assuring robust rotational control of implant, for example through plate fixation of APC to host bone.

7) Retaining or restoring critical soft tissue attachments, such as deltoid, pectoralis major, remaining rotator cuff and subscapularis

Example below from Ben Sharareh, past UW Shoulder Fellow

8) Minimizing stress risers at distal end of APC, especially in osteoporotic bone (avoid ending plate and stem at same level, “protecting the whole bone”). Example below from Jonah Hebert-Davies, UW Shoulder Faculty.

9) Optimizing stability of glenohumeral articulation (selection of glenosphere diameter of curvature and lateral offset, tensioning using polyethylene liner of appropriate thickness, avoiding unwanted contact between humerus and scapula (neck, acromion).

The example below shows a glenosphere exchange to a larger diameter, inferior offset at a revision for humeral loosening with massive humeral bone loss. The new glenosphere optimizes soft tissue tension and compression.

Below are some of the relevant articles on revision reverse total shoulder arthroplasty in shoulders with loss of humeral bone.

2009 Revision Arthroplasty with Use of a Reverse Shoulder Prosthesis-Allograft Composite recommended allograft-prosthesis composites in cases with humeral defects ranging from 3.5 to 15.0 cm.

2013 Revision surgery of reverse shoulder arthroplasty points to the association of bone loss with humeral loosening, lack of rotational stability, and infection.

2014 The metaphyseal bone defect predicts outcome in reverse shoulder arthroplasty for proximal humerus fracture sequelae found that the clinical outcome was influenced by a metaphyseal bone defect of more than 3 centimeters and degenerative changes of the teres minor.

2016 Long-term analysis of revision reverse shoulder arthroplasty using cemented long stems emphasized the importance of sufficient quantity and quality of distal humeral bone in obtaining fixation with long stem cemented humeral components.

2017 Large diaphyseal-incorporating allograft prosthetic composites: when, how, and why : Treatment of advanced proximal humeral bone loss found that well-fixed humeral stems could be treated with short metaphyseal allografts in most cases. Loose stems required longer diaphyseal-incorporating allografts. Noncemented stems required diaphyseal grafts in most cases, compared to cemented stems which required larger grafts in one-third of cases.

2018 Humeral Bone Loss in Revision Shoulder Arthroplasty indicated proximal humeral allograft for revisions of shoulders with 5 cm or more proximal humeral bone loss).

2019 Clinical outcomes following reverse shoulder arthroplasty-allograft composite for revision of failed arthroplasty associated with proximal humeral bone deficiency: 2- to 15-year follow-up."

2019 Humeral Bone Loss in Revision Total Shoulder Arthroplasty: the Proximal Humeral Arthroplasty Revision Osseous Insufficiency (PHAROS) Classification System divided bone loss into three regions (epiphysis, metadiaphysis above the deltoid insertion, and diaphysis below the deltoid insertion) and bone quality by cortical thinning of greater or less than 50% of the expected thickness. Epiphyseal bone loss is subdivided into isolated compromise of the medial calcar or greater tuberosity. The authors provided radiographic examples of each degree of bone loss.

2023 Humeral bone defects in revision shoulder arthroplasty divided bone loss based on the involvement of five segments of the humerus, as shown below This classification helps accounts for loss of bone in regions of stabilizing muscle attachments.

This post was prepared with the great help and direction from Mihir Sheth, M.D., UW shoulder fellow.

Sunday, September 17, 2023

Shoulder instability

Glenohumeral instability is one of the most common disabling conditions of the shoulder. Yet given the great flexibility of the joint and the small, shallow socket provided by the glenoid

it is a wonder that the shoulder remains as stable as it does with everything we ask it to do

In order to understand, evaluate and manage shoulder instability, one needs to understand how the joint is normally stabilized. Our late fellow, Doug Harryman, did a great job explaining shoulder stability in these two videos: Shoulder Mechanics 1 and Shoulder Mechanics 2.

The principles of shoulder stability are detailed in Chapter 3 of the freely available Practical Evaluation and Management of the Shoulder (see this link.).

While the knee is stabilized by ligaments that remain isometric through its range of flexion and extension, the shoulder has no isometric structures that limit its range of motion. The surrounding soft tissues remain lax in most functional positions of the shoulder, except those performed at the extremes of shoulder motion (such as in the baseball pitch shown above).

(N.B.: laxity is not the same thing as instability (see Laxity of the normal glenohumeral ioint: A quantitative in vivo assessment)

While the hip is stabilized by a deep acetabular socket (which limits hip range of motion when its rim is contacted by the femur), the shoulder's socket is shallow, allowing it a great range of impingement-free motion.

The essential mechanism stabilizing the shoulder is concavity compression, a mechanism that functions throughout the range of shoulder motion. Just as the compressive effect of gravity stabilizes the golf ball in the small, shallow concavity of the tee

the glenohumeral joint is stabilized when the net force on the humeral head compresses it into the small, shallow glenoid concavity of the glenoid

As long as the net force acting on the humeral head passes within the glenoid concavity, the joint is stable. The glenoid arc provides a range of positions in which this condition can be met.

The glenoid bone, cartilage and labrum each contribute to the concavity.

The concavity is less in the anteroposterior direction than in the superiorinferior direction.

As a result, the joint's stability from front to back is less than its stability from top to bottom.

If the concavity is compromised, the range of stable positions is reduced.

As pointed out in A Prospective Analysis of Patients With Anterior Versus Posterior Shoulder Instability, while anterior instability is often traumatic, posterior instability more commonly arises from repeated overloading and wear of the posterior supporting structures from pushing and lifting activities that differentially load the back of the joint.

Recurrent posterior instability may be accompanied by progressive loss of the supportive posterior glenoid cartilage and bone (see Prospective Evaluation of Posterior Glenoid Bone Loss After First-time and Recurrent Posterior Glenohumeral Instability Events).

Stability is also compromised if the net force is not directed within the glenoid concavity.

Fortunately, the scapula can usually be positioned so that the concavity is aligned with the compressive force.

For example, if the hand pushes forward while the scapula is retracted, the force on the humerus is not aligned with the glenoid socket and stability is threatened.

However, if the hand pushes forward while the scapula is protracted, the force on the humerus is closely aligned with the glenoid socket, so stability is optimized.

Functional instability has been defined as instability from pathological muscle activation patterns resulting in malalignment of the net humeral force with the glenoid (see Characteristics of functional shoulder instability).

Often functional instability can be managed by patient education and physical training to strengthen the cuff muscles that provide compression of the humeral head into the glenoid concavity while avoiding positions that risk force malalignment (such as press ups without scapular protraction as shown earlier). In refractory cases, muscular retraining may be enhanced by using electrical stimulation (see Shoulder-Pacemaker Treatment Concept for Posterior Positional Functional Shoulder Instability: A Prospective Clinical Trial).

The specifics of surgical treatment for glenohumeral instability are beyond the scope of this post. However, understanding the concavity compression mechanism of shoulder stability can help guide practice:

(1) when instability results from deficiencies in the labrum, cartilaginous lip, or glenoid bone, consider restoring the glenoid concavity through Bankart repair or bony procedures

(2) when instability results from malalignment of the net humeral force with the glenoid, consider restoring the constraints to excessive motion, using capsular repair/shift, rotator interval plication and/or remplissage.

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