Authors of section

Authors

Martin Jaeger, Frankie Leung, Wilson Li

Executive Editors

Peter Trafton

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MIO - Plate fixation

1. Introduction

The lesser tuberosity fracture may result in weakness if it is not fixed. The primary task of the plate is to stabilize the metaphyseal fracture that requires disimpaction to correct significant angulation.

2. Principles

Risk of axillary nerve injury

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 axillary nerve should be protected by limiting the incision to less than 5 cm distal to the acromial edge.

Lesser tuberosity reduction

Proper reduction of the lesser tuberosity is difficult. Its position is hard to visualize with intraoperative image intensification.
Medial displacement of the lesser tuberosity (A) produces an intraarticular anterior step which can compromise internal rotation.
Lateral displacement of the lesser tuberosity (B) obstructs the bicipital groove and may compromise the bicipital tendon. If possible, correct reconstruction of the bicipital groove is desirable to allow sliding of the tendon. An alternative would be tenodesis of the long head of the biceps.

Lesser tuberosity, suture reduction and fixation

Suture fixation of the lesser tuberosity

Sutures in the subscapularis tendon insertion aid both reduction and fixation of the lesser tuberosity. Once reduced, lesser tuberosity sutures are tied to a similar suture in the infraspinatus tendon for provisional fixation. Ultimately, these sutures contribute significantly to primary stability of the lesser tuberosity.

Lesser tuberosity fixed with sutures

Tension band sutures in addition to plate and screws

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.

Additional tension band sutures

Angular stable versus standard plates

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.

Plating options

3. Patient preparation and approaches

Patient preparation

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

hemiarthroplasty

Approaches

The anterolateral approach is more suited for lesser tuberosity reduction and fixation, though a separate anterior incision may be required.

mio plate fixation

4. Reduction and preliminary fixation

Reduction

Sequence of repair:

  1. Reduce and fix the lesser tuberosity to the humeral head (thereby converting the 3-part fracture into a 2-part situation)
  2. Reduce the proximal humeral fragment to the shaft and fix it.
Reduction

Place rotator cuff sutures

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.

Rotator cuff sutures: Subscapularis and supraspinatus tendon

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.

Infraspinatus tendon

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

Stay sutures

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

Preliminary traction suture

… 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.

Pull anteriorly

Reduction of the lesser tuberosity

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

Direct reduction of the lesser tuberosity

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

Instrumentation

Preliminary fix the lesser tuberosity

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

Preliminary fix the tuberosity

Reduction of the head fragment

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

Reduction of the head fragment

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.

Using an elevator

Preliminary fixation

After the tuberosity and humeral head have been reduced and stabilized with sutures, there may be no need for additional preliminary fixation, but it might be advantageous to use additional K-wires to secure the position of the humeral head relative to the humeral shaft. This is illustrated with 2 retrograde K-wires. Make sure to place them from anterior in order to avoid interference with the foreseen plate position.

If the greater tuberosity is multifragmentary it might become necessary to use additional small K-wires in order to fix separate fragments.

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

Preliminary fixation

5. Plate position

Correct plate position

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)
Correct plate position

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: plate too close 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
Pitfall: plate too proximal

6. Plate fixation

Positioning wires (for plate location)

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.

Positioning wires (for plate location)

Insert plate

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.

Plate insertion

Attach plate to humerus

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.

Plate to humerus attachment

Fix plate to the humeral head

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.

Fix plate to the humeral head

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.

“Woodpecker”-drilling technique

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.

Determine screw length

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

Insert screw

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.

All four proximal screws should be inserted as previously described.

Insert screws into humeral shaft

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.

Completed osteosynthesis

Additional fixation of the lesser tuberosity

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.

Additional fixation of the lesser tuberosity

Supplementary tension band sutures

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

Supplementary tension band sutures

7. Final check of osteosynthesis

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.

In the beach chair position, the C-arm must be directed appropriately for orthogonal views.

8. Overview of rehabilitation

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.

Progressive exercises

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.

nonoperative

Special considerations

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.

Shoulder rehabilitation protocol

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