MIO - Plate fixation

The displaced greater tuberosity must be reduced and fixed stably. The metaphyseal fracture also requires reduction, usually provisional reduction with K-wires and, finally, stable plating.

Fractures with metaphyseal comminution should not be treated with minimally invasive plate osteosynthesis because exposure of the medial column is necessary for a stable reduction.

In the following procedure, we show the reduction and fixation for fractures involving the greater tuberosity. For specific details on reduction of the lesser tuberosity see Limited open reduction and preliminary fixation of lesser tuberosity and humeral head.

The main structure at risk is the axillary nerve. The axillary nerve should be protected by limiting the incision to less than 5 cm distal to the acromial edge, by palpating the area to determine the location of the nerve, and by avoiding maneuvers that stretch the nerve during reduction and fixation. Remember the course of the nerve when placing K-wires.

The greater tuberosity is typically displaced posterosuperiorly due to the pull of the rotator cuff. The humeral head is typically rotated posteriorly due to the pull of the subscapularis tendon on the intact lesser tuberosity. Both aspects of deformity have to be corrected precisely. If there is a valgus/varus malposition of the humeral head this has to be corrected to allow a proper reduction of the greater tuberosity.

Sutures in the rotator cuff tendon insertions aid manipulation, reduction, and temporary fixation of a proximal humerus fracture.
Traction on the sutures helps achieve reduction. When tied, they bring the fragments together and stabilize them.

Sutures placed through the insertions of each rotator cuff tendon increase stability, and should be used as well as the plate and screws, particularly for more comminuted and/or osteoporotic fractures. With osteoporotic bone, the tendon insertion is often stronger than the bone itself, so that sutures placed through the insertional fibers of the tendon may hold better than screws or sutures placed through bone.
These additional sutures are typically the last step of fixation.

This form of fixation was referred to as a “Tension band suture fixation”. We now prefer the term “Neutralizing sutures” because the tension band mechanism cannot be applied consistently to each component of the fracture fixation. An explanation of the limits of the Tension band mechanism/principle can be found here.

This procedure describes proximal humeral fracture fixation with an angular stable plate (A). Sometimes, these implants are not available. Standard plates provide an alternative option, for example the modified cloverleaf plate (B). Presently, the specific indications, advantages, and disadvantages of angular stable and standard plates are being clarified. There is some evidence that angular stable plate provide better outcomes. In addition to type and technique of fixation, the quality of reduction, the soft-tissue handling, and the characteristics of the injury and patient significantly influence the results. There is no evidence that the use of angular stable plates will overcome these other factors.

It is recommended to perform this procedure with the patient in a beach chair position.

Choose the approach based on tuberosity fracture location:

• Anterolateral approach
• Transdeltoid lateral approach

Sequence of repair:

1. Reduction/fixation of the tuberosity (thereby converting the 3-part fracture into a 2-part situation)
2. Reduction/fixation of the proximal humeral fragment to the shaft

Subscapularis and supraspinatus tendon
Begin by inserting sutures into the subscapularis tendon (1) and the supraspinatus tendon (2). Place these sutures just superficial to the tendon’s bony insertions. These provide anchors for reduction, and temporary fixation of the greater and lesser tuberosities.

Infraspinatus tendon
Next, place a suture into the infraspinatus tendon insertion (3). This can be demanding, and may be easier with traction on the previously placed sutures, with properly placed retractors, and/or repositioning the arm.

Use of stay sutures
Anterior traction on the supraspinatus tendon helps expose the greater tuberosity and infraspinatus tendon.

Insert a preliminary traction suture into the visible part of the posterior rotator cuff …

… and pull it anteriorly. This will expose the proper location for a suture in the infraspinatus tendon insertion. Then the initial traction suture is removed.

Pearl: larger needles
A stout sharp needle facilitates placing a suture through the tendon insertion.

Direct reduction of the greater tuberosity fragment is performed by pulling the sutures or, …

… with instruments (eg, elevator) applied either through the incision (as illustrated) or through a separate stab incision.

Tighten and tie the transverse sutures in order to preliminarily fix the greater tuberosity fragment. Thereby, the 3-part fracture is converted into a 2-part situation.

Distal traction, perhaps augmented with increased angulation, will help to reduce the fracture.

Use of an elevator
Sometimes, the incision allows insertion of an elevator to disimpact the humeral head, or to help to correct inclination/torsion and to restore a normal relationship of the medial fracture surface. The proximal fragment should be reduced anatomically to the shaft.
The actual process of reduction is done with image intensifier control.

Quite often, the humeral head is not stable enough and requires additional preliminary fixation using 2 or 3 K-wires. Make sure to place them from anterior in order to avoid interference with the foreseen plate position.

Confirmation of reduction
The correct reduction must be confirmed in both AP and lateral views using image intensifier control.

The correct plate position is:

1. about 5-8 mm distal to the top of the greater tuberosity
2. aligned properly along the axis of the humeral shaft
3. slightly posterior to the bicipital groove (2-4 mm)

Pitfall 1: plate too close to the bicipital groove
The bicipital tendon and the ascending branch of the anterior humeral circumflex artery are at risk if the plate is positioned too close to the bicipital groove. (The illustration shows the plate in correct position, posterior to the bicipital groove).

Pitfall 2: plate too proximal
A plate positioned too proximal carries two risks:

1. The plate can impinge the acromion
2. The most proximal screws might penetrate or fail to securely engage the humeral head

To ensure appropriate plate position, somewhat obscured by a small incision, it helps to place temporary K-wires that can be used for radiographically controlled guidance.
Insert 2 positioning K-wires, one at the lateral border the bicipital groove and the other at the tip of the greater tuberosity. (These positioning wires can be used for provisional tuberosity fixation.)
The anterior positioning K-wire sets the location for the anterior edge of the plate, 2-4 mm lateral to the bicipital groove.
The proximal positioning K-wire determines the proximal edge of the plate, 5-8 mm distal to the tip of the greater tuberosity.

Identify the axillary nerve by palpating on the undersurface of the deltoid muscle. This helps protect it during plate insertion.
Insert the plate, assembled on an aiming device, under the deltoid muscle, and slide it distally under the deltoid and along the humerus. Always keep the plate in contact with bone.

Pearl: suturing the deltoid muscle To prevent extending the deltoid muscle split and increasing risk of axillary nerve injury, place a suture at the distal end of the split.

Position the plate in the planned and marked location on the proximal humerus. Fix it temporarily to the bone with K-wires. Proximally, two wires are placed through specific holes in the aiming device. Distally, use a percutaneously placed K-wire sleeve.

Confirm correct plate position with x-ray.

Drill hole
Use the aiming device with drill sleeves to drill holes for the proximal screws. Make sure not to perforate the humeral head.

Follow the manufacturers technique guide.

Avoiding intraarticular screw placement
Screws that penetrate the humeral head may significantly damage the glenoid cartilage. Primary penetration occurs when the screws are initially placed. Secondary penetration is the result of subsequent fracture collapse. Drilling into the joint increases the risk of screws becoming intraarticular.

Two drilling techniques help to avoid drilling into the joint.

Pearl 1: “Woodpecker”-drilling technique (as illustrated)
In the woodpecker-drilling technique, advance the drill bit only for a short distance, then pull the drill back before advancing again. Keep repeating this procedure until subchondral bone contact can be felt. Take great care to avoid penetration of the humeral head.

Pearl 2: Drilling near cortex only
Particular in osteoporotic bone, one can drill only through the near cortex. Push the depth gauge through the remaining bone until subchondral resistance is felt.

Determine screw length
The intact subchondral bone should be felt with an appropriate depth gauge or blunt pin to ensure that the screw stays within the humeral head. The integrity of the subchondral bone can be confirmed by palpation or the sound of the instrument tapping against it. Typically, choose a screw slightly shorter than the measured length.

Insert screw
Insert a locking-head screw through the screw sleeve into the humeral head.

All four proximal screws should be inserted as previously described.
Remember the plate lies deep to the axillary nerve. Screws should not be place through the danger zone where the nerve may be injured.

Insert two to three screws into the humeral shaft, below the danger zone, with aiming device and appropriate, percutaneously placed screw insertion sleeves.

Completed osteosynthesis
The illustration shows the completed osteosynthesis.

Lag screw fixation of the lesser tuberosity might be considered.
This may be unnecessary if a secure subscapularis suture has been placed. If in doubt, it is recommended to check the fixation stability of the lesser tuberosity clinically by rotating the arm. If there is any micro movement visible or palpable one should consider insertion of an additional lag screw.

In minimally invasive plate fixation, it is wise to increase stability by adding supplementary neutralizing sutures to attach the rotator cuff tendons to the plate.

Using image intensification, carefully check for correct reduction and fixation (including proper implant position and length) at various arm positions. Ensure that screw tips are not intraarticular.

The shoulder is perhaps the most challenging joint to rehabilitate both postoperatively and after conservative treatment. Early passive motion according to pain tolerance can usually be started after the first postoperative day - even following major reconstruction or prosthetic replacement. The program of rehabilitation has to be adjusted to the ability and expectations of the patient and the quality and stability of the repair. Poor purchase of screws in osteoporotic bone, concern about soft-tissue healing (eg tendons or ligaments) or other special conditions (eg percutaneous cannulated screw fixation without tension-absorbing sutures) may enforce delay in beginning passive motion, often performed by a physiotherapist.

The full exercise program progresses to protected active and then self-assisted exercises. The stretching and strengthening phases follow. The ultimate goal is to regain strength and full function.

Postoperative physiotherapy must be carefully supervised. Some surgeons choose to manage their patient’s rehabilitation without a separate therapist, but still recognize the importance of carefully instructing and monitoring their patient’s recovery.

Activities of daily living can generally be resumed while avoiding certain stresses on the shoulder. Mild pain and some restriction of movement should not interfere with this. The more severe the initial displacement of a fracture, and the older the patient, the greater will be the likelihood of some residual loss of motion.

Progress of physiotherapy and callus formation should be monitored regularly. If weakness is greater than expected or fails to improve, the possibility of a nerve injury or a rotator cuff tear must be considered.

With regard to loss of motion, closed manipulation of the joint under anesthesia, may be indicated, once healing is sufficiently advanced. However, the danger of fixation loosening, or of a new fracture, especially in elderly patients, should be kept in mind. Arthroscopic lysis of adhesions or even open release and manipulation may be considered under certain circumstances, especially in younger individuals.

Mechanical support should be provided until the patient is sufficiently comfortable to begin shoulder use, and/or the fracture is sufficiently consolidated that displacement is unlikely.

Once these goals have been achieved, rehabilitative exercises can begin to restore range of motion, strength, and function.
The three phases of nonoperative treatment are thus:

1. Immobilization
2. Passive/assisted range of motion
3. Progressive resistance exercises

Immobilization should be maintained as short as possible and as long as necessary. Usually, immobilization is recommended for 2-3 weeks, followed by gentle range of motion exercises. Resistance exercises can generally be started at 6 weeks. Isometric exercises may begin earlier, depending upon the injury and its repair. If greater or lesser tuberosity fractures have been repaired, it is important not to stress the rotator cuff muscles until the tendon insertions are securely healed.

Glenohumeral dislocation: Use of a sling or sling-and-swath device, at least intermittently, is more comfortable for patients who have had an associated glenohumeral dislocation. Particularly during sleep, this may help avoid a redislocation.

Weight bearing: Neither weight bearing nor heavy lifting are recommended for the injured limb until healing is secure.

Implant removal: Implant removal is generally not necessary unless loosening or impingement occurs. Implant removal can be combined with a shoulder arthrolysis, if necessary.

Generally, shoulder rehabilitation protocols can be divided into three phases. Gentle range of motion can often begin early without stressing fixation or soft-tissue repair. Gentle assisted motion can frequently begin within a few weeks, the exact time and restriction depends on the injury and the patient. Resistance exercises to build strength and endurance should be delayed until bone and soft-tissue healing is secure. The schedule may need to be adjusted for each patient.

Phase 1 (approximately first 3 weeks)

• Immobilization and/or support for 2-3 weeks
• Pendulum exercises
• Gently assisted motion
• Avoid external rotation for first 6 weeks

Phase 2 (approximately weeks 3-9)

If there is clinical evidence of healing and fragments move as a unit, and no displacement is visible on the x-ray, then:

• Active-assisted forward flexion and abduction
• Gentle functional use week 3-6 (no abduction against resistance)
• Gradually reduce assistance during motion from week 6 on

Phase 3 (approximately after week 9)

• Add isotonic, concentric, and eccentric strengthening exercises
• If there is bone healing but joint stiffness, then add passive stretching by physiotherapist