Posterior glenoid osteoplasty for unstable dislocating shoulders. Surgery to build up the back of the glenoid socket using an osteotomy and graft can restore shoulder anatomy and lessen pain and improve function.
Edited By: Frederick A. Matsen III, M.D., Winston J. Warme, MD
Last updated Friday, October 16, 2009
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Figure 1 - The concavity of the normal glenoid requires that the humeral head be lifted out of the socket in order to translate
Figure 2 - Normally the humeral head must climb out of the depth of the glenoid to translate across its face
Figure 3 - When the posterior aspect of the socket is flat, there is minimal resistance to posterior translation of the humeral head across the glenoid
Figure 4 - The posterior glenoid osteoplasty restores the posterior glenoid concavity and the posterior glenoidogram
Figure 5 - The change in glenoid shape and glenoidogram from before to after the surgery is dramatic
Figure 6 - A six-centimeter incision is based on the major posterior axillary crease
Figure 7 - A six-centimeter incision is based on the major posterior axillary crease
Figure 8 - The posterior deltoid is split between its posterior one third and its anterior two thirds beginning two centimeters medial to the posterior corner of the
Figure 9 - The split is deepened to expose the posterior rotator cuff muscles
Figure 10 - The dissection of the posterior rotator cuff muscles is facilitated by externally rotating the arm
Figure 11 - Looking at the shoulder with the deltoid muscle reflected, we can see the axillary nerve exiting the quadrilateral space (between the long head of the triceps, the humeral shaft, the teres minor and the teres major). The shoulder capsule is approached as indicated by the dotted line between the infraspinatus and the teres minor. The teres minor protects the axillary nerve during the procedure.
Figure 12 - The posterior glenohumeral capsule is exposed and inspected. Often a defect or very thin portion of the capsule can be identified
Figure 13 - A horizontal incision is made in the thinnest part of the capsule
Figure 14 - Through the posterior capsular opening a blunt elevator is inserted into the joint to determine the plane of the glenoid
Figure 15 - The plane of the intended glenoid osteotomy is determined parallel to and one centimeter medial to the articular surface
Figure 16 - The plane of the intended glenoid osteotomy is determined parallel to and one centimeter medial to the articular surface. A drill hole is made from anterior to posterior in the plane of the intended osteotomy. The depth of this hole is measured with a depth gauge, revealing the anteroposterior dimension of the glenoid in the plane of the intended osteotomy. A 3/4 inch flat and strong osteotome is marked with sterile tape at a length equal to 3/4 of the anteroposterior dimension of th
Figure 17 - The depth of the osteotome is controlled by paying attention to the sterile tape mark
Figure 18 - The osteotome is inserted with a slight posterior inferior to anterior superior angulation
Figure 19 - A posterior inferior opening wedge osteotomy is created one centimeter medial to the glenoid lip in the same as the face of the glenoid articular surface. The depth of the osteotome is controlled by paying attention to the sterile tape mark. This osteotomy is opened with successive levering steps to ?bend? the bone, rather than breaking. The glenoid surface is observed as the osteotomy is deepened to prevent penetration of the joint surface.
Figure 20 - The bone graft is harvested using an oscillating saw
Figure21 - A 20 mm x 20 mm x 6 mm bone graft is harvested from the posterior superior scapular spine
Figure22 - The bone graft is fashioned to a 20 mm x 15 mm x 5 mm wedge using a pine cone burr
Figure 23 - The wedge-shaped graft is inserted into the osteotomy so that its cortex is just inside that of the posterior glenoid
Figure 24 - Getting the arm to externally rotate while lying down
Figure 25 - External rotation for strengthening the rotator cuff
Summary
Overview
A common cause of posterior dislocations and posterior instability of
the shoulder is the loss of the rim or lip on the back of the socket of
the shoulder joint. The posterior glenoid concavity can be restored by
a procedure known as posterior glenoid osteoplasty.
Characteristics of posterior shoulder instability
The normal shoulder is a marvel of mobility and stability. It
provides more motion than any other joint in the human body, yet the
humeral head (ball of the shoulder joint) remains precisely centered in
the glenoid (the socket of the joint) throughout the wide range of
shoulder activities. One of the main stabilizing mechanisms is
concavity compression, in which the head of the humerus is held into
the glenoid concavity by the action of the rotator cuff (much like a
golf ball is held into the concavity of a golf tee) (see figure 1).
Because of this concavity, the humeral head must rise up over the
glenoid lip before it can translate out of the socket. The path taken
by the humeral head during this translation is called the
"glenoidogram" (see figure 2).
When the rim at the back of the socket is underdeveloped or worn,
the humeral head can translate out the back of the joint more easily,
without having to lift up over the rim. In this situation, the
glenoidogram becomes flattened (see figure 3).
Possible benefits of posterior glenoid osteoplasty
When recurrent posterior instability or dislocations interfere with
the comfort and security of the shoulder and when these symptoms cannot
be controlled by other means, a posterior glenoid osteoplasty performed
by an experienced shoulder surgeon can usually restore the stability of
the joint (see figures 4 and 5).
Types of surgery recommended
Posterior glenoid osteoplasty can help restore the function and comfort of shoulders that are unstable posteriorly.
The goal of posterior glenoid osteoplasty for recurrent posterior
instability is to restore the depth of the back of the shoulder socket
or glenoid. This is accomplished through a posterior approach that does
not require any muscles or tendons to be detached.
This procedure cannot be accomplished arthroscopically. The incision
is made in the normal skin creases around the shoulder, leaving a
minimal surgical scar (see figure 6).
If the stability is lost because of a deficiency in the posterior
glenoid lip, posterior glenoid osteoplasty can help restore stability
by building up this lip.
When performed by an experienced shoulder surgeon, posterior glenoid
osteoplasty has an excellent chance of restoring stability to the
shoulder. This procedure is particularly valuable in patients who have
stretchy or thin ligaments and those who have failed previous surgeries.
Who should consider posterior glenoid osteoplasty?
Posterior glenoid osteoplasty is considered for patients with recurrent
posterior instability or feelings of unsteadiness or apprehension that
have not responded to a well-conducted rehabilitation program.Surgical options
A number of different surgical procedures for recurrent posterior glenohumeral instability have been described.
These include arthroscopic suturing, burning the inside of the
capsule with laser treatment or with radio frequency heat probes as
well as open surgical tightening of the capsule. None of these
procedures restores the posterior lip of the socket. All of these
procedures are at risk for failure if the ligaments and capsule are
thin, stretchy or weak. None of these procedures provides a robust
augmentation of the posterior glenoid lip.
Posterior glenoid osteoplasty has the advantages of providing a
robust change in the stabilizing geometry of the shoulder. It does not
depend on healing of compromised ligamentous tissue or a predictable
response to thermal energy.
Effectiveness
In the hands of an experienced shoulder surgeon, posterior glenoid
osteoplasty can help restore to the unstable shoulder some of its lost
comfort and function. With a good rehabilitation effort and with the
avoidance of additional injuries, the result of the surgery should last
for a long time.Urgency
Surgery for instability is not an emergency. Posterior glenoid
osteoplasty is an elective procedure that can be scheduled when
circumstances are optimal. The patient has time to become informed and
to select an experienced surgeon.
Before surgery is undertaken, the patient needs to:
- be in optimal health,
- understand and accept the risks and alternatives of surgery, and
- understand the postoperative rehabilitation program.
Posterior glenoid osteoplasty should be performed when conditions
are optimal. Particularly in the case of atraumatic instability, an
extended effort at non-operative management is suggested. Usually a 6-
to 12-week try at strengthening exercises is sufficient to determine
whether exercises are likely to be effective.
Risks
The risks of posterior glenoid osteoplasty include but are not limited to the following:
- infection
- injury to nerves and blood vessels
- inability to carry out the planned repair
- stiffness of the joint
- tear of the rotator cuff
- pain
- persistent instability
- arthritis
- the need for additional surgeries
There are also risks associated with anesthesia, including death.
An experienced shoulder surgery team will use special techniques to minimize these risks, but cannot totally eliminate them.
Managing risk
Many of the risks of surgery for instability can be managed
effectively if they are promptly identified and treated. Infections may
require a wash out in the operating room and subsequent antibiotic
treatment. Blood vessel or nerve injury may require repair. Stiffness
may require exercises or additional surgery. Persistent instability or
arthritis may require the consideration of additional surgery.
If the patient has questions or concerns about the course after surgery, the surgeon should be informed as soon as possible.
Preparation
Posterior glenoid osteoplasty is considered for healthy and
motivated individuals in whom recurrent posterior shoulder dislocations
or apprehension interfere with shoulder function.
Successful posterior glenoid osteoplasty depends on a partnership
between the patient and the experienced shoulder surgeon. The patient's
motivation and dedication are important elements of the partnership.
Patients should optimize their health so that they will be in the best
possible condition for this procedure. Smoking should be stopped a
month before surgery and not resumed for at least three months
afterwards--ideally never. This is because smoking interferes with
healing of the repair. All heart, lung, kidney, bladder, tooth, or gum
problems should be managed before surgery. Any infection may be a
reason to delay the operation.
The patient's shoulder surgeon needs to be aware of all health
issues, including allergies and non-prescription and prescription
medications being taken. Some of these may need to be modified or
stopped. For instance, aspirin and anti-inflammatory medication may
affect the way the blood clots. The skin around the shoulder must be
clean and free from sores and scratches.
Before surgery, patients should consider the limitations,
alternatives, and risks of surgery. Patients should also recognize that
the result of surgery depends in large part on their efforts in
rehabilitation after surgery.
The patient needs to plan on being less functional than usual for up
to twelve weeks after the shoulder repair. Lifting, pushing, pulling,
and some activities of daily living can place stresses on the repair.
Performing usual work or chores may be difficult during this time.
Plans for necessary assistance need to be made before surgery. For
people who live alone or those without readily available help,
arrangements for home help should be made well in advance.
The shoulder surgeon should answer any questions about the surgery or the recovery period.
Timing
Posterior glenoid osteoplasty can be delayed until the time that is best for the patient's overall well being.Costs
The surgeon's office should be able to provide a reasonable estimate of:
- the surgeon's fee, and
- the hospital fee.
Surgical team
Posterior glenoid osteoplasty is a technically demanding procedure that
is ideally performed by an experienced shoulder surgeon in a medical
center accustomed to performing these procedures at least several times
a month. Patients should inquire as to the number of posterior glenoid
osteoplasties that the surgeon performs each year and the number of
these procedures performed in the medical center each year.Finding an experienced surgeon
Surgeons specializing in shoulder instability surgery may be located
through university schools of medicine, county medical societies, state
orthopedic societies, or professional groups such as the American
Shoulder and Elbow Surgeons Society, which offers a worldwide directory of shoulder and elbow surgeons on its web site.
Facilities
Posterior glenoid osteoplasty is often performed in a major medical
center that performs these procedures on a regular basis. These centers
have surgical teams and facilities specially designed for this type of
surgery. They also have nurses and therapists who are accustomed to
assisting patients in their recovery from this type of surgery.
Technical details
Posterior glenoid osteoplasty is a highly technical procedure; each step plays a critical role in the outcome.
The goal is to perform this surgery without detaching muscle or
tendons--this ?rotator cuff on? approach speeds the recovery because
strengthening exercises can be started right away after surgery.
After the anesthetic has beena dministered, the patient is placed
prone on the operating table, and the shoulder has been prepared, a
cosmetic incision is made in a natural skin crease at the back of the
shoulder (see figure 7).
This incision allows access to the seam between the posterior and
middle thirds of the deltoid (see figure 8). Splitting this seam allows
access to the rotator cuff muscles without detaching or damaging the
important deltoid muscle, which is responsible for a significant
portion of the shoulder's power (see figure 9). All scar tissue is
removed from the space beneath the deltoid.
The posterior rotator cuff muscles are relaxed by passive external
rotation (see figure 10). The interval between the infraspinatus and
the teres minor is split, leaving the teres minor between the split and
the axillary nerve (see figure 11). This split is opened without any
tendon detachment providing excellent exposure of the posterior
shoulder capsule (see figure 12). The capsule is incised horizontally
(see figure 13). If there is a weak area of capsule the incision is
made through it, so that it can be reinforced at the time of closure. A
blunt elevator is inserted to indicate the plane of the joint (see
figure 14). The posterior glenoid bone cut is planned one centimeter
medial to the joint surface and parallel to it (see figure 15). A drill
hole is made in the plane of the intended cut and the depth of this
hole is measured. The osteotome is marked with sterile tape at a
distance equal to three fourths of the depth of the glenoid at the
osteotomy site (see figure 16).
The osteotome is driven into the glenoid, parallel to the joint
surface, down to the level of the tape marking three quarters of the
anteroposterior distance of the glenoid (see figure 17). The osteotome
is inserted in a posterior inferior to anterior superior direction (see
figure 18). The osteotomy is opened by successive prying (see figure
19).
Through the same skin incision, a 20 mm by 20 mm by 6 mm bicortical
graft is harvested from the posterior acromion using an oscillating saw
(see figures 20 and 21). Using a power burr, the graft is fashioned
into a wedge measuring 20 mm by 15 mm by 5 mm. The graft is then
inserted into the opened osteotomy at the back of the glenoid (see
figure 22). The graft is driven in until it is just below the surface
of the bone of the glenoid--this securely locks it in place (see figure
23).
The capsule split is closed, reinforcing any weaknesses.
The deltoid split is repaired side to side and any detachment of the
deltoid from the posterior spine of the scapula is repaired to bone.
A cosmetic closure of the skin incision is carried out, dressings are applied, and the arm is placed in a sling.
Anesthetic
Posterior glenoid osteoplasty is performed under a general anesthetic.
A brachial plexus nerve block may be administered as an adjunctive
anesthetic and to provide anesthesia for several hours after the
surgery. The patient may wish to discuss their preferences with the
anesthesiologist before surgery.Length of posterior glenoid osteoplasty
Posterior glenoid osteoplasty usually takes approximately one hour, but
the preoperative preparation and the postoperative recovery may add
several hours to this time. Patients often spend two hours in the
recovery room and about two days in the hospital after surgery.
Pain and pain management
Recovery of comfort and function after posterior glenoid osteoplasty continues for many months.
Shoulder instability surgery is a major surgical procedure that
involves cutting of skin and removal of scar tissue, as well as
suturing of tendons and bone. The pain from this surgery is managed by
the anesthetic and by pain medications. Immediately after surgery,
strong medications (such as morphine or Demerol) are often given by
injection. Within a day or so, oral pain medications (such as
hydrocodone or Tylenol with codeine) are usually sufficient.Use of medications
Initially pain medication is administered usually intravenously or
intramuscularly. Sometimes patient controlled analgesia (PCA) is used
to allow the patient to administer the medication as it is needed.
Hydrocodone or Tylenol with codeine are taken by mouth. Intravenous
pain medications are needed usually for only the first day or two after
the procedure. Oral pain medications are needed usually for only the
first two weeks after the procedure.Effectiveness of medications
Pain medications can be very powerful and effective. Their proper use
lies in the balancing of their pain relieving effect and their other,
less desirable effects. Good pain control is an important part of the
postoperative management.Important side effects
Pain medications can cause drowsiness, slowness of breathing,
difficulties in emptying the bladder and bowel, nausea, vomiting, and
allergic reactions. Patients who have taken substantial narcotic
medications in the recent past may find that usual doses of pain
medication are less effective. For some patients, balancing the
benefits and side effects of pain medication is challenging. Patients
should notify their surgeon if they have had previous difficulties with
pain medication or pain control.Hospital stay
After surgery the patient spends about an hour in the recovery room. A
drainage tube is sometimes used to remove excess fluid from the
surgical area. The drain is usually removed on the second day after
surgery. Bandages cover the incision. They are usually changed the
second day after surgery.Hospital discharge
Patients are discharged as soon as the incision is dry, the shoulder
is comfortable with oral pain medications, the patient can perform the
range of motion exercises, the patient feels comfortable with the plans
for managing the shoulder, and the home support systems for the patient
are in place. Discharge is usually on the second day after surgery.
Walking and use of the arm for gentle activities (with the elbow at
the side) are often encouraged soon after surgery, but the surgeon
should be consulted for the specifics of each individual case.
Gentle activities of daily living are often permitted with the
operated arm; however, lifting anything heavier than a cup of coffee or
using the arm for forceful activities must avoided for six to twelve
weeks, depending on the procedure.
Convalescent assistance
Management of the patient's limitations requires advance planning to
accomplish the activities of daily living during the recovery period.
Patients may require some assistance with self-care, activities of
daily living, shopping, and driving for about one month after surgery.
Recovery of comfort and function after shoulder instability surgery
continues for many months after the surgery. Improvement in some
activities may be evident as early as three months. With persistent
effort, patients make progress for as long as a year after surgery.
Physical therapy
A progressive rehabilitation program after posterior glenoid
osteoplasty is critical for achieving optimal shoulder function. For
the first six weeks, the elbow is not allowed away from the side, but
rotational stretching and strengthening exercises are carried out.
Shoulders may become stiff after surgery, so early protected motion
is often suggested. However, the repair needs to be protected from
re-injury, especially during the healing period. Using the �rotator
cuff on� technique described above enables the patient to begin
strengthening exercises immediately after surgery.
Depending on the nature of the procedure, the surgeon will often
prescribe some gentle motion exercises within a limited range of
movement.
The surgeon often wishes to check the mobility of the shoulder two
or three weeks after surgery, to assure that the shoulder has not
become too stiff.
Rehabilitation options
It is often most effective for patients to carry out their own
exercises so that they are done frequently, effectively and
comfortably. Usually, a physical therapist or the surgeon instructs the
patient in the exercise program and advances it at a rate that is
comfortable for the patient.
For the first six weeks after surgery, emphasis is placed on
protected motion. For the second six weeks, emphasis is placed on
strengthening exercises to so that strong muscles will protect the
shoulder as it returns to normal activities.
The patient is asked to carry out exercises to maintain flexibility
by carrying out specific, yet simple exercises beginning immediately
after the surgery (see figure 24).
Movie:
The goal is for the shoulder to rotate the arm fully with the elbow
at the side--from full external rotation to full internal rotation. As
these exercises become comfortable, specific strengthening exercises
are added, especially in external rotation (see figure 25).
Movies:
At the end of six weeks and after a comfortable rotation and
strength have been achieved, the patient starts using the arm out to
the side and then in increasingly forward positions as specified by the
surgeon.
The strengthening exercises are continued for a year after surgery to optimize the dynamic stability of the shoulder.
Can rehabilitation be done at home?
In general the exercises are best performed by the patient at home.
Occasional visits to the surgeon or therapist may be useful to check
the progress and to review the program.
Usual response
Patients are almost always satisfied with the increases in range of
motion, comfort, and function that they achieve with the exercise
program. If the exercises are uncomfortable, difficult or painful, the
patient should contact the surgeon promptly.Risks
This is a safe rehabilitation program with little risk.Duration of rehabilitation
The strengthening exercises are continued for a year after surgery to optimize the dynamic stability of the shoulder.Returning to ordinary daily activities
In general, patients are able to perform gentle activities of daily
living with the operated arm at the side starting two to three weeks
after surgery. Walking with the arm protected is strongly encouraged.
Driving should wait until the patient can perform the necessary
functions comfortably and confidently. This may take up to one month if
the surgery has been performed on the right shoulder, because of the
increased demands on the right shoulder for shifting gears.
With the consent of their surgeon, patients can often return to
activities such as swimming, golf and tennis at six months after their
surgery.
Stressful activities and activities with the arm in extreme
positions must be avoided until six months after the surgery and then
only if the shoulder is comfortable and strong.
Long-term patient limitations
Patients should avoid activities that involve major impact (chopping
wood, contact sports, sports with major risk of falls) or heavy loads
(lifting of heavy weights, heavy resistance exercises) until one year
after surgery, and until the shoulder has excellent strength and range
of motion--essentially equivalent to the opposite side. In this way the
risk of re-injury is minimized.Costs
The surgeon and therapist should be able to provide the information on
the usual cost of the rehabilitation program. The program is quite
cost-effective, because it is heavily based on home exercises.
Summary of posterior glenoid osteoplasty for posterior shoulder instability
In the hands of an experienced surgeon, posterior glenoid
osteoplasty can be a most effective method for restoring comfort and
function to a shoulder with recurrent posterior instability,
dislocations, or apprehension in a healthy and motivated patient when
these symptoms do not respond to a supervised exercise program.
The best results are obtained when the surgery restores a deficient
posterior lip to the shoulder socket (glenoid). In this situation the
surgeon has a good opportunity to reconstruct the specific abnormality
causing the instability.
Pre-planning and persistent rehabilitation efforts will help assure the best possible result for the patient.
Surgery for posterior shoulder instability at the University of Washington, Department of Orthopaedics and Sports Medicine, Seattle, Washington
If you are interested in making an appointment to discuss this procedure in Seattle, you can request an appointment using our online referrals website. To request a referral online, please click here. You can also call 206-598-BONE (2663) to make an appointment. Our clinical center is located in Seattle Washington, USA