Postsurgical Rehabilitation of Posterior Instability


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Postsurgical Rehabilitation of Posterior Instability


Evan W. James, MD; Kenneth M. Lin, MD; Lawrence V. Gulotta, MD; and Samuel A. Taylor, MD


Posterior shoulder instability is relatively rare compared to anterior or multidirectional instability, accounting for just 2% to 5% of unstable shoulders.13 Posterior instability can result from an acute, traumatic posterior dislocation event, such as following a motor vehicle accident with the arm in the forward-flexed adducted position, or from repetitive microtrauma, such as the posteriorly directed forces experienced by a football lineman. Posterior subluxation of the humeral head relative to the glenoid often results in tearing of the posterior labrum from the posterior glenoid rim and attenuation of the glenohumeral capsule.4 The labrum is a rim of fibrocartilage surrounding the glenoid that functions to increase congruency of the glenohumeral joint, thereby providing improved stability to the shoulder. When a posterior labral tear occurs, there is glenohumeral incongruency and relative laxity of the posterior glenohumeral capsule leading to instability to the glenohumeral joint when a posteriorly directed force is exerted on the upper extremity.


Treatment options are initially nonsurgical and include physical therapy focused on dynamic stabilization exercises. When conservative approaches prove insufficient, then operative shoulder stabilization is indicated followed by a phase-specific rehabilitation program. Although many first-time posterior dislocators may initially try nonoperative management, a high percentage of these patients eventually require surgical stabilization. A recent study by Woodmass et al, which evaluated 143 patients with posterior shoulder instability from 1994 to 2015, included 79 patients initially managed nonoperatively.5 Of the nonoperatively managed patients, 46% converted to surgery between 1 and 10 years after the diagnosis, and 70% of patients converted to surgery by final follow-up.


Posterior shoulder stabilization is typically performed arthroscopically using suture anchors to stabilize the posterior labrum on the glenoid rim with or without capsular plication (Figure 21-1).6,7 Postoperative immobilization occurs in neutral rotation. After surgery, a rehabilitation program under the direction of the treating surgeon and an experienced physical therapist is critical to achieving an excellent outcome. The purpose of this chapter is to review postsurgical rehabilitation guidelines following posterior shoulder stabilization, including bracing, adjunctive treatments, phase-specific rehabilitation protocols, and return-to-play guidelines. The protocol outlined in this chapter was developed in cooperation with the Hospital for Special Surgery Department of Rehabilitation with minor modifications and has been used with great success among the authors of this chapter.8


PHASE-SPECIFIC REHABILITATION PROTOCOL


The primary goal of rehabilitation following posterior shoulder stabilization is to reestablish stability of the glenohumeral joint. This is accomplished by restoring normal shoulder strength, flexibility, range of motion, and scapulohumeral rhythm, with the ultimate goal of returning to sports and other activities. We follow a general progression through a phase-based approach reviewed below, which includes phase I (immediate postoperative), phase II (protected range of motion), phase III (range of motion normalization and neuromuscular re-education), phase IV (normalization of strength, flexibility, and scapulohumeral rhythm), phase V (return to play), and phase VI (maintenance).



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Figure 21-1. Arthroscopic images from a 16-year-old male baseball pitcher with posterior shoulder instability. Arthroscopic images viewed from an anterior superior portal show: (A) a posterior labrum torn off the posterior glenoid rim with redundant posterior capsule, (B) mobilization of the torn labrum with a labral elevator, (C) debridement of the posterior glenoid rim, and (D) the final repair using a knotless suture anchor construct.


Phase I (Weeks 0 to 2)


The immediate postoperative period typically consists of the first 2 weeks after surgery. During this phase, emphasis is placed on pain control and protecting the surgical repair. Patients are required to wear a shoulder immobilizer, or “gunslinger” shoulder brace, in neutral rotation at all times except when performing approved home exercises (Figure 21-2). Patients must remain non-weight–bearing on the operative extremity and avoid internal rotation. Patients should be educated on how to safely don and doff their sling, as well as how to perform activities of daily living such as bathing and dressing while abiding by range of motion limitations. The immobilizer should be positioned in the scapular plane with the arm in neutral internal and external rotation, which avoids excessive strain on the posterior capsule and surgical repair. Full supported range of motion of the elbow, wrist, and digits is encouraged to avoid stiffness and aid in edema reduction. Formal physical therapy is typically not employed during this immediate postoperative phase. Adjunctive treatments including cryotherapy, oral analgesics, and oral anti-inflammatory medications are recommended on an as-needed basis.


Phase II (Weeks 2 to 4)


Some clinicians wish to begin formal physical therapy 2 weeks postoperatively, whereas others may wish to abstain until week 4 postoperatively. In either case, the focus during this time is to initiate early controlled range of motion without compromising the integrity of the surgical repair (Table 21-1). Emphasis is placed on minimizing pain, swelling, and inflammation while continuing to protect the surgical repair. Active-assisted range of motion may be used during this phase in which the patient uses the unaffected extremity to control the operative extremity through the desired range of motion. Active-assisted forward flexion is performed in the scapular plane with the patient in the supine position to mitigate the effects of gravity and assist in scapular stabilization while the operative extremity is fully extended at the elbow. The shoulder is then forward flexed in a controlled fashion while supported by the unaffected extremity to a maximum of 90 degrees. Active-assisted external rotation is performed with the elbow flexed at 90 degrees while the unaffected extremity guides the operative extremity into external rotation. Cane-assisted active-assisted motion may be used to guide the operative extremity through the desired arc of motion. Pain, however, should be closely monitored and excessive stretching beyond the desired range of motion must be avoided. Elbow, wrist, and digit range of motion is encouraged through a full arc of motion. Gripping exercises using a stress ball or therapy putty may also be used for distal motion in the operative extremity.



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Figure 21-2. A “gunslinger” brace with an abduction pillow in neutral rotation as viewed in the (A) anterior, (B) lateral, and (C) oblique planes is recommended during the first 4 weeks after surgery.



In addition to range-of-motion exercises, isometric exercises with submaximal effort may also initiated during this phase. Scapular isometrics are performed with the patient lying on his or her unaffected side. Rotator cuff isometrics are performed in a seated or standing position with the shoulder in neutral rotation. Isometrics are performed both for internal and external rotation. Again, activities that produce pain should be avoided because this is often indicative of excessive strain on the posterior capsule.


A shoulder immobilizer should be continued at all times except when performing rehabilitation exercises. Horizontal cross-body adduction and internal rotation are limited to neutral to avoid excessive stretch on the posterior capsule. Adjunctive treatments including cryotherapy, electrical stimulation, oral analgesics, and oral anti-inflammatory medications may again be used on an as-needed basis. Finally, the surgeon and physical therapist should work together to provide a home-based exercise program with clearly delineated exercises and precautions to perform outside formal physical therapy.


Phase III (Weeks 4 to 6)


The goal of phase III is to improve shoulder range of motion and neuromuscular activation with isometric exercises (Table 21-2). Patients may discontinue the shoulder immobilizer beginning at postoperative week 4. Active assisted motion is performed in the scapular plane to a maximum of 90 degrees of forward flexion and 30 degrees of external rotation. Internal rotation is gradually advanced in this phase from neutral to 45 degrees. Cross-body horizontal adduction is limited to neutral. Abduction with external rotation to 30 degrees is initiated, which off-loads stress on the posterior capsule when performing scapular-stabilization exercises. Rotator cuff isometrics in internal and external rotation and deltoid isometrics should be performed with submaximal effort.


Jul 27, 2021 | Posted by in ORTHOPEDIC | Comments Off on Postsurgical Rehabilitation of Posterior Instability
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