CHAPTER 28 – Anatomic Acromioclavicular Joint Reconstruction

Acromioclavicular joint separation represents one of the most common shoulder injuries in general orthopedic practice. The most common mechanism of this injury is a fall with a direct force to the lateral aspect of the shoulder and with the arm in an abducted position. Depending on the magnitude of injury to the acromioclavicular joint capsule and ligaments as well as to the coracoclavicular ligaments, these injuries can be classified by increasing severity as type I through type VI. Typically, the first- and second-degree sprains of the acromioclavicular joint, otherwise known as type I and type II injuries, are treated conservatively; most return to preinjury status. Whereas the treatment of type III dislocations remains controversial, high-grade injuries—typically types IV, V, and VI—with greater than 100% displacement in either a posterior or inferior direction are typically treated surgically.

The literature is replete with surgical techniques to address complete acromioclavicular dislocations, including primary repair of the coracoclavicular ligaments, augmentation with autogenous tissue (coracoacromial ligament), augmentation with absorbable and nonabsorbable suture as well as with prosthetic material, and coracoclavicular stabilization with metallic screws. The Weaver-Dunn technique with transfer of the coracoacromial ligament has been the most popular procedure in the acute and chronic injury. Several more recent reports have described good results with modifications of the Weaver-Dunn technique. However, studies observed compromised results in patients who had residual subluxation or dislocation after surgery.

From a biomechanical perspective, the importance of the coracoclavicular ligaments and acromioclavicular ligaments in controlling superior and horizontal translation of the distal clavicle has been elucidated. In fact, failure to surgically reproduce the conoid, trapezoid, and acromioclavicular ligament function with current techniques may explain the observed incidence of recurrent instability and pain.

I advocate use of a separate, more robust graft source, rather than the coracoacromial ligament, to improve surgical results. The use of a free autogenous or allograft tendon has been further supported in our biomechanics laboratory.

Preoperative Considerations

The pain associated with acromioclavicular joint injury may be difficult to localize because of the complex sensory innervation of the joint. An acute injury as described before is an important indicator in the diagnosis. Conversely, the lack of a discrete injury with acromioclavicular joint pain and joint separation is more consistent with a degenerative condition. Given an acute injury, it is important to obtain the level of perceived pain, its location, and any history of previous shoulder injuries. During examination, the patient should be upright so that the weight of the arm helps exaggerate any deformities.

History

	•	Acute traumatic event
	•	Distal clavicular fracture (not always obvious)
	•	Age of the patient—physeal fracture
	•	Prior surgical procedures (distal clavicle resection)
	•	Current physical limitations and disability
	•	Reconstruction for instability, not pain
	•	Failure of at least 3 months of conservative treatments
	•	Pain with forward elevation
	•	Posterior headache (nuchae)

Physical Examination

Acromioclavicular joint examination

	•	Inspection ( Fig. 28-1 )
	•	Tenderness to palpation
	•	Anterior-posterior translation or mobility
	•	Superior-inferior translation or mobility
	•	Reduction of the distal clavicle with shoulder shrug differentiates type III from type V (distal clavicle buttonhole through deltotrapezial fascia)

Range of motion

	•	Arm positioning limitation
	•	Inability to lift arm
	•	Pain with forward elevation and wing out

Strength testing

Differential Diagnosis

Other causes of pain must be ruled out:

	•	Cervical spine disease: trapezial spasm
	•	Thoracic outlet syndrome
	•	Scapular dyskinesis
	•	Hyperlaxity
	•	Coracoid fracture

Factors Affecting Surgical Planning

•

Prior surgeries, incisions

Imaging

	•	Zanca view: 10- to 15-degree cephalad tilt ( Fig. 28-2 )
	•	Axillary, outlet, and anteroposterior views of the shoulder in the scapular plane
	•	Cross-arm adduction view: anteroposterior shoulder—measure clavicle override
	•	Magnetic resonance imaging: labral injury masquerading as acromioclavicular joint pain
	•	Computed tomographic scan: nondisplaced lateral clavicle or acromion fracture

Indications

	•	Advocate reconstruction even for symptomatic type III injuries in laborers, throwers, and overhead athletes
	•	Instability after distal clavicle excision
	•	No absolute indications

Contraindications

Reconstruction is contraindicated in painless, functional grade III separation and with regional pain syndrome, unclear diagnosis, adhesive capsulitis, and other shoulder problems.

Surgical Planning

	•	Semitendinosus allograft or autograft
	•	Reasonable expectations of the patient and compliance with postoperative regimen
	•	Postoperative sling immobilization for 6 weeks

Surgical Technique

Anesthesia and Positioning

The patient is placed in the beach chair position after induction of general anesthesia. Be sure the head is mobile for possible repositioning. A small towel bump is placed on the medial scapular edge to elevate the coracoid anterior. Drape wide to expose the sternoclavicular joint and posterior clavicle. The arm is draped free.

Surgical Landmarks and Portals

Landmarks

	•	Clavicle
	•	Acromion
	•	Coracoid process

Portals

	•	Scope first
	•	Standard posterior arthroscopy port
	•	Anterior rotator interval port

Examination Under Anesthesia

	•	Evaluate anterior-posterior translation as well as superior-inferior translation of the distal clavicle.
	•	Evaluate glenohumeral range of motion and stability.

Specific Steps (
Box 28-1

)

1. Exposure

A No. 10 blade scalpel is used to make a 6-cm longitudinal incision, centered over or slightly medial to the coracoid. Medial and lateral skin flaps are elevated with a needle-tipped bovie. Gelpi retractors assist with exposure. A transverse incision is made along the midaxis of the clavicle extending into the acromioclavicular joint. Full-thickness flaps of the superior acromioclavicular joint capsule are elevated superiorly and inferiorly with a needle-tipped bovie. The anterior and posterior portion of the distal clavicle is completely exposed (
Fig. 28-3

). If acromioclavicular joint arthrosis is present, 5 mm of distal clavicle is resected. Many surgeons perform a distal clavicle resection (
Fig. 28-4

). However, there is tremendous variability in the acromioclavicular joint, and there seems to be tremendous stability from an intact acromioclavicular joint. For that reason, I believe that it may be advantageous to preserve the distal clavicle and have done so in select patients.

Box 28-1 

Surgical Steps

1.    Exposure    2.    Passing under the coracoid    3.    Clavicular tunnels    4.    Graft preparation    5.    Graft passage    6.    Biotenodesis fixation    7.    Acromioclavicular joint capsular ligament repair    8.    Closure

The medial and lateral coracoid base is exposed with a Cobb elevator. A headlight may be useful for this portion of the procedure. Care is taken to avoid excessive medial dissection to prevent musculocutaneous nerve injury.

2. Passing under the Coracoid

A specially designed cannulated passing device (Arthrex, Inc., Naples, Fla) is passed medial to lateral around the coracoid. A FiberWire or FiberStick (Arthrex, Inc., Naples, Fla) is then shuttled through the cannulated handle and retrieved laterally at the tip. This passing stitch is later used for graft passage around the coracoid (
Fig. 28-5

).

An alternative means of coracoid graft fixation is biotenodesis screw fixation of the looped end of the semitendinosus graft in a coracoid base bone tunnel. This is best achieved by positioning the 7-mm offset ACL guide on the medial coracoid base and reaming an 8- or 9-mm bone tunnel.

3. Clavicular tunnels

The conoid ligament tunnel is established with a guide pin drilled 4.5 cm medial from the intact lateral distal clavicle edge. This is positioned along the posterior superior cortex and is marked before distal clavicle resection. The pin is directed at 30 degrees anterior, aiming toward the coracoid. A second guide pin from the Arthrex biotenodesis set is drilled central on the clavicle’s anteroposterior dimension and 1.5 cm lateral to the medial pin. This tunnel will be used to reconstruct the trapezoid ligament and is again directed 30 degrees anterior toward the coracoid (Figs. 28-6 and 28-7 [6] [7]). A 5.5-mm reamer is used to ream both tunnels (
Fig. 28-8

). The reamer is removed by hand twisting after penetration of the far cortex to avoid tunnel widening.

4. Graft Preparation

An allograft semitendinosus graft is contoured to fit through a 5.5-mm tunnel. No. 2 FiberWire is used to place baseball stitches at each end of the graft (
Fig. 28-9

).

5. Graft Passage

The initially passed FiberWire or FiberStick is used to shuttle the prepared semitendinosus graft along with an additional No. 2 FiberWire around the coracoid process. The accessory FiberWire will provide secondary fixation. The free ends of the semitendinosus graft along with the free No. 2 FiberWire are shuttled into the respective clavicular bone tunnels by use of a suture-passing device (
Fig. 28-10

).

6. Biotenodesis Fixation

A 5.5 × 8-mm PEEK (polyetheretherketone) tenodesis screw is then loaded onto the biotenodesis screwdriver (Arthrex, Inc., Naples, Fla). The nitinol loop retriever is used to pass the FiberWire through the cannulated screwdriver system. With countertension on the opposite graft end, the PEEK screw is inserted flush to the cortical surface. The clavicle is then overreduced with downward pressure from a Cobb elevator. A superiorly directed force on the humerus will also assist in reducing the clavicle. If the distal clavicle is preserved, I avoid overreducing the acromioclavicular joint.

A second PEEK tenodesis screw is inserted into the second clavicular tunnel through the FiberWire suture. The graft is tensioned as the screw is inserted. The order of tunnel fixation does not matter. The FiberWire is tensioned and tied with surgeon knots. The graft ends are then sutured to one another, and the excess graft is excised.

7. Superior Acromioclavicular Joint Capsular Ligament Repair

No. 2 FiberWire stitches are used to imbricate the superior acromioclavicular joint capsular ligaments in a pants-over-vest configuration. This will offer additional anteroposterior stability to the reconstruction. The deltotrapezial fascia is also repaired in this step if full-thickness flaps of fascia and acromioclavicular joint capsular ligament were elevated in a single layer.

8. Closure

After copious wound irrigation, the subcutaneous tissues are closed with 2-0 Vicryl sutures. A 3-0 Monocryl is used to perform a subcutaneous skin closure. The wound is injected with bupivacaine (Marcaine).

Postoperative Considerations

Follow-up

	•	Sutures are removed at 1 week.
	•	Patients are seen at 1, 2, 3, and 6 months and then annually.
	•	Postoperative radiographs include bilateral Zanca views to measure coracoid-clavicular distance ( Fig. 28-11 ).

Rehabilitation

	•	A platform brace (Lehrman) is worn for 6 weeks.
	•	Immediate pendulum exercises are begun, with limitation of passive external rotation to 30 degrees and passive forward flexion to 90 degrees.
	•	Active range of motion is started at 8 weeks.
	•	Strengthening is started at 12 to 16 weeks.
	•	Sports-specific activities and return to full athletics are allowed at 16 to 24 weeks.
	•	Return to heavy labor is allowed at 6 months.

Complications

	•	Infection
	•	Sterile abscess from FiberWire or PEEK screw reaction
	•	Potential clavicle fracture from stress riser effect on bone tunnels. Unpublished three- and four-point load data revealed diminished stress riser effect when clavicular tunnels are filled with tenodesis screws.
	•	Construct failure
	•	Potential musculocutaneous nerve injury
	•	Persistent pain

PEARLS

•    Include the sternoclavicular joint in the operative field to allow wide exposure.    •    Place a small towel bump under the medial scapular edge.    •    Bullet the semitendinosus ends to allow easy graft passage.    •    Make sure the head of the patient can be repositioned to the side, allowing room for conoid tunnel drilling.    •    Instead of repositioning the head, the clavicle can be displaced anteriorly with a towel clip to allow access for conoid tunnel drilling.    •    The skin incision is over the coracoid process, more medial than usual (not over the acromioclavicular joint).    •    The medial skin incision allows direct visualization of the coracoclavicular ligament and coracoid.    •    Tag the deltoid and trapezial fascia for good repair.    •    Pass sutures under the coracoid either medial to lateral or lateral to medial.    •    If sutures are passed lateral to medial, make sure the medial coracoid base is exposed and position a Darrach retractor on the medial base to “catch” the passing device.    •    Do not power-spin the reamer out to avoid tunnel widening.    •    Overreduce the acromioclavicular joint if the distal clavicle is resected, abutting the clavicle to the coracoid process.    •    Do not overreduce the clavicle if the distal clavicle is preserved.    •    The 5.5 × 8-mm PEEK screws are inserted into a 5.5-mm bone tunnel (line to line).    •    Drill up by 0.5 mm if the graft is too big for screw fixation.    •    Insert the screw anterior to the graft to adequately re-create the posteriorly positioned coracoclavicular ligaments.    •    A postoperative platform brace (Lehrman) is prescribed for 6 weeks.

Results

Results of studies of acromioclavicular joint reconstruction are shown in
Table 28-1

.

Author	Study	Native Coracoclavicular Ligament	Anatomic Coracoclavicular Ligament Reconstruction	Coracoacromial Transfer
Lee et al[6] (2003)	Cadaver	650 N (load to failure)	700 N (load to failure)	150 N (load to failure)
			Semitendinosus
Costic et al[1] (2004)	Cadaver	60.8 ± 5.2 N/mm (stiffness)	23.4 ± 5.2 N/mm (stiffness)
		560 ± 206 N (load to failure)	406 ± 60 N (load to failure)
			Semitendinosus
Grutter and Petersen[3] (2005)	Cadaver	815 N	774 N	483 N
			Flexor carpi radialis
Mazzocca et al[7] (2006)	Cadaver		396.4 ± 136.42 N	354.3 ± 100.26 N