What is the step-by-step procedure for treating a fracture of the proximal humerus using Philos (proximal humeral locking plate) plating?

Step-by-Step Procedure for Proximal Humerus Fracture Fixation with PHILOS Plating

The PHILOS (Proximal Humeral Internal Locking System) plate provides stable fixation with good functional outcomes for proximal humerus fractures, particularly in elderly patients with osteopenic bone. 1, 2 The procedure involves careful patient positioning, surgical approach, fracture reduction, and meticulous plate placement to avoid complications.

Preoperative Assessment

1. Imaging Studies:

   • Standard radiographs in multiple views
   • CT scan with 3D reconstruction for complex fracture patterns 3
   • Assessment of fracture pattern using Neer classification system 3

2. Patient Evaluation:

   • Assess bone quality, especially in elderly patients
   • Evaluate for associated rotator cuff tears (present in up to 40% of proximal humeral fractures) 3
   • Rule out neurovascular injuries

Surgical Procedure

1. Anesthesia and Positioning

• General anesthesia or regional block (interscalene)
• Beach chair position with head elevated 30-45 degrees
• Ensure the shoulder is completely free and can be manipulated during surgery
• Prepare and drape the entire upper extremity

2. Surgical Approach

Two main approaches can be used:

• Deltopectoral Approach (more common):

  • Make a 10-15 cm incision starting from the coracoid process and extending laterally along the deltopectoral groove
  • Identify and protect the cephalic vein
  • Develop the interval between deltoid and pectoralis major muscles
  • Retract the cephalic vein laterally or medially
  • Identify and protect the long head of biceps tendon

• Transdeltoid Lateral Approach (for minimally invasive technique):

  • Make a 5-7 cm lateral incision starting below the acromion
  • Split the deltoid fibers in line with its fibers
  • Protect the axillary nerve (approximately 5-7 cm below the acromion)

3. Fracture Exposure and Reduction

• Identify the fracture fragments (head, greater tuberosity, lesser tuberosity, shaft)
• Place non-absorbable sutures (No. 2 or 5) through the rotator cuff tendons near their insertion for manipulation
• Reduce the fracture fragments anatomically
• Use K-wires for temporary fixation
• Confirm reduction with fluoroscopy

4. PHILOS Plate Application

• Position the plate 5-8 mm distal to the upper end of the greater tuberosity
• Position the plate 2-4 mm posterior to the bicipital groove
• Ensure the plate is not placed too high to avoid subacromial impingement 4, 5
• Fix the plate temporarily with K-wires through the plate holes

5. Screw Fixation

• Insert the shaft screws first to secure the plate to the humeral shaft
• Use locking screws in the humeral head, directed in different directions (divergent pattern)
• Ensure screws do not penetrate the articular surface (use fluoroscopy)
• The locking screws should be 5-10 mm short of the subchondral bone to avoid penetration
• Place at least 4-5 locking screws in the humeral head for adequate stability

6. Additional Fixation

• Use non-absorbable sutures to secure rotator cuff tendons and tuberosity fragments to the plate
• For comminuted fractures, consider bone grafting if there is significant bone loss

7. Final Assessment

• Check final reduction and hardware position with fluoroscopy in multiple views
• Ensure no screw penetration into the joint
• Test range of motion to ensure no impingement
• Irrigate the wound thoroughly

8. Closure

• Repair the rotator interval if opened
• Close the deltopectoral interval or deltoid split
• Close subcutaneous tissue and skin in layers
• Apply sterile dressing and arm sling

Postoperative Management

1. Immediate Care:

   • Arm immobilization in a sling
   • Pain management
   • Prophylactic antibiotics for 24 hours

2. Rehabilitation Protocol:

   • Begin passive range of motion exercises on day 2 post-surgery 6
   • Progress to active-assisted exercises at 4-6 weeks 6
   • Start strengthening exercises at 8-12 weeks

3. Follow-up:

   • Clinical and radiographic evaluation at 2 weeks, 6 weeks, 3 months, and 6 months
   • Assess for fracture union (average time to union: 10-14 weeks) 2, 6
   • Monitor for complications

Common Complications and Prevention

• Subacromial Impingement (3.6-21.4%): Ensure proper plate positioning 4, 5
• Avascular Necrosis (7.2-12%): Minimize soft tissue stripping of the humeral head 4, 5
• Screw Penetration (3.6%): Use fluoroscopy and ensure screws are 5-10 mm short of subchondral bone 5
• Varus Malposition: Ensure adequate medial column support 5
• Non-union (2.4%): Consider bone grafting for comminuted fractures 5

Special Considerations

• In elderly patients with osteoporotic bone, ensure adequate screw purchase and consider augmentation techniques 3
• For severely comminuted fractures in elderly patients, consider reverse shoulder arthroplasty as an alternative 3
• Assess for associated rotator cuff tears, which may need to be addressed during surgery 3

The PHILOS plate system has shown good to excellent results in 57-60% of cases with proper surgical technique 4, 5, making it a reliable option for treating proximal humerus fractures.