The patient is placed in a beachchair position on the edge of the operating
table, with the upper part of the body flexed 60° at the waist
(Fig. 1). The arm is placed on
an armrest and must be freely movable without the elbow touching the armrest
to minimize trauma to the ulnar nerve (Fig.
2). This is important for exposure and anterior displacement of
the entire humeral head by extension and external rotation of the arm.
The implantation of the DUROM cup (Zimmer, Winterthur, Switzerland) is
carried out with use of the deltopectoral approach. The skin incision extends
distally from the coracoid in a slight curve to the insertion of the deltoid
muscle (Fig. 3). The cephalic
vein is identified between the pectoral and deltoid muscles, and the approach
is made medial to the vein, thereby preserving the venous branches draining
the deltoid. The subacromial space is identified, and both the deltoid muscle
laterally and the conjoint tendon of the coracobrachialis and the short head
of the biceps medially are retracted with a Langenbeck retractor
(Fig. 4). The subscapularis is
exposed by external rotation of the arm. This muscle is detached by a vertical
incision placed 1 cm lateral to the musculotendinous junction, and it is
secured with three to four loops of strong, nonabsorbable stay sutures
(Fig. 5).
The subscapularis muscle is then mobilized, and the joint capsule is
exposed. A wide release of the anterior and inferior capsule is necessary in
order to expose the entire head of the humerus, with anterior displacement
created by subsequent adduction, extension, and external rotation of the arm.
One or two Hohmann retractors can be placed around the neck of the humerus to
support the anterior subluxation of the humeral head
(Fig. 6).
At this juncture, the osteophytes, especially along the inferior head-neck
junction, are carefully and thoroughly removed to enable optimal assessment of
the anatomical configuration of the humeral head with respect to size and
angle.
The alignment guide is used to determine the desired position of the DUROM
cup on the basis of the anatomical orientation of the humeral head and
preoperative radiographic templating. It is important to determine the center
of the humeral head with use of either reamers or the cup from the alignment
guide (Fig. 7-A). The alignment
guide is then placed parallel to the arm and forearm with use of the humerus
as a reference for the inclination angle and the forearm as a reference for
retroversion of the cup (Figs. 7-B and
7-C).
The desired inclination and retroversion of the component are now
determined. Most commonly, the inclination angle is from 130° to 135°,
and the retroversion angle is between 30° and 45°. If a massive
rotator cuff tear is present, the DUROM cup is implanted in a slightly more
valgus position, without repair of the rotator cuff, so that secondary
articulation of the DUROM cup with the acromion is facilitated. Next, a 2-mm
Kirschner wire is drilled through the guide; precise orientation of the guide
and the Kirschner wire at the center of the humeral head is essential for the
subsequent accurate positioning of the prosthesis. It is important to drill
the Kirschner wire through the alignment guide into the humeral head and
through the lateral cortex of the humerus for stable fixation
(Fig. 8).
The alignment guide is then removed, taking care to retain the Kirschner
wire, which is used as a guide for subsequent reaming of the humeral head.
The reamers are used in decreasing sizes and are passed over the Kirschner
wire to ream the humeral head down to subchondral bone. When the reamers are
used, it is important not to violate the inferior medial cortex of the humerus
(Fig. 9).
A trial prosthesis is placed over the Kirschner wire to check for the
correct size and depth of the implant. When the desired size is achieved and
the anatomical configuration of the humeral head is reconstructed by the
implant, a cannulated drill is placed over the Kirschner wire to create the
hole for the central stem of the cup (Fig.
10). The Kirschner wire is then removed, the trial prosthesis is
placed, and the range of motion and functional positioning of the joint is
tested. The position of the lower edge of the trial cup is then marked with an
additional pin to mark the implantation depth
(Fig. 11).
The trial cup is then removed, and the humeral bone is prepared. If
sclerosis is present in the subchondral bone, additional drill-holes are
created in the sclerotic zone for better cement fixation. Pulsed lavage is
used for bone cleansing (Fig.
12). If there is good bone stock in the humeral head, cementless
implantation (a press-fit) is performed. In the reported series, however, only
cemented DUROM cups were used. In this case, the cup is filled with
low-viscosity cement—the stem remains uncemented—and the
prosthesis is implanted immediately. Pressurizing the cement is performed with
an implant punch pressurizer to enhance cement penetration into the cancellous
bone. At this point, the pin marking the implantation depth is very helpful
for fully seating the implant into the final desired position. Excess cement
is then carefully removed, as is the marker pin
(Fig. 13).
The subscapularis is repaired with use of nonabsorbable sutures, either end
to end or with transosseous sutures. In the case of impingement of the tendon
of the long head of the biceps, the proximal, intra-articular portion can be
resected and the tendon secured in its sulcus between the greater and lesser
tuberosities. The subscapularis and supraspinatus tendons are then sutured
together with absorbable suture to close the rotator interval. Further
reconstruction of the rotator cuff is performed as needed.
An incision into the coracoacromial ligament should be performed only as an
exception. This ligament is typically preserved throughout the procedure.
A suction drain is applied, and the wound is closed. Postoperative
radiographs are made in the anteroposterior view only
(Figs. 14-A and 14-B).
Postoperatively, an immobilizing dressing supports the shoulder. The
patient removes the arm from the dressing several times a day to perform
pendulum exercises. External rotation is limited to a degree determined
intraoperatively to protect the subscapularis and supraspinatus tendon
repairs. Abduction is usually limited to 60° to 90°, and flexion is
limited to 90°, for the first four weeks. Passive physiotherapy is
performed for the first two weeks after the operation and is followed by an
active-assisted program for another two weeks. Active range of motion without
limitation is permitted after four weeks. If a massive rotator cuff tear was
repaired, postoperative rehabilitation is modified by limiting flexion to
60° for the first six weeks.
CRITICAL CONCEPTSINDICATIONS:Inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and
ankylosing spondylitis)Primary and secondary osteoarthritisOsteonecrosis of the humeral headRotator cuff-tear arthropathyCONTRAINDICATIONS:Complex fractures of the humeral head or the proximal part of the
humerusOsteonecrosis of more than one-third of the humeral headDestructive arthropathy from any etiology with loss of the humeral head
contourCysts involving more than one-third of the humeral headOsteopathy with insufficient bone stockAcute infectionCharcot arthropathyCRITICAL CONCEPTSPITFALLS:Incorrect anteroposterior position (anterior-posterior offset) of the
implant can lead to impingement of the subscapularis or infraspinatus
tendon.Incorrect mediolateral position (medial-lateral offset) of the implant can
lead to impaired range of motion or increasing glenoid erosions due to high
soft-tissue tension.Incorrect implant depth, with an increased prominence above the tuberosity,
can lead to impingement on the tendon of the long head of the biceps.An oversized cup can lead to overstuffing of the joint, with severe pain on
movement. A larger humeral head component leads to a more stable situation
because of increased soft-tissue tension and full articulation with the
glenoid and acromion. However, excessive size can result in excessive tension
in the rotator cuff with impaired function and increased pain.AUTHOR UPDATE:The procedure has been neither changed nor modified since the original
article was published.
CRITICAL CONCEPTS
INDICATIONS:
Inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and
ankylosing spondylitis)Primary and secondary osteoarthritisOsteonecrosis of the humeral headRotator cuff-tear arthropathy
Inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and
ankylosing spondylitis)
Primary and secondary osteoarthritis
Osteonecrosis of the humeral head
Rotator cuff-tear arthropathy
CONTRAINDICATIONS:
Complex fractures of the humeral head or the proximal part of the
humerusOsteonecrosis of more than one-third of the humeral headDestructive arthropathy from any etiology with loss of the humeral head
contourCysts involving more than one-third of the humeral headOsteopathy with insufficient bone stockAcute infectionCharcot arthropathy
Complex fractures of the humeral head or the proximal part of the
humerus
Osteonecrosis of more than one-third of the humeral head
Destructive arthropathy from any etiology with loss of the humeral head
contour
Cysts involving more than one-third of the humeral head
Osteopathy with insufficient bone stock
Acute infection
Charcot arthropathy
CRITICAL CONCEPTS
PITFALLS:
Incorrect anteroposterior position (anterior-posterior offset) of the
implant can lead to impingement of the subscapularis or infraspinatus
tendon.Incorrect mediolateral position (medial-lateral offset) of the implant can
lead to impaired range of motion or increasing glenoid erosions due to high
soft-tissue tension.Incorrect implant depth, with an increased prominence above the tuberosity,
can lead to impingement on the tendon of the long head of the biceps.An oversized cup can lead to overstuffing of the joint, with severe pain on
movement. A larger humeral head component leads to a more stable situation
because of increased soft-tissue tension and full articulation with the
glenoid and acromion. However, excessive size can result in excessive tension
in the rotator cuff with impaired function and increased pain.
Incorrect anteroposterior position (anterior-posterior offset) of the
implant can lead to impingement of the subscapularis or infraspinatus
tendon.
Incorrect mediolateral position (medial-lateral offset) of the implant can
lead to impaired range of motion or increasing glenoid erosions due to high
soft-tissue tension.
Incorrect implant depth, with an increased prominence above the tuberosity,
can lead to impingement on the tendon of the long head of the biceps.
An oversized cup can lead to overstuffing of the joint, with severe pain on
movement. A larger humeral head component leads to a more stable situation
because of increased soft-tissue tension and full articulation with the
glenoid and acromion. However, excessive size can result in excessive tension
in the rotator cuff with impaired function and increased pain.
AUTHOR UPDATE:
The procedure has been neither changed nor modified since the original
article was published.