What is the detailed step‑by‑step open reduction and internal fixation (ORIF) procedure using a Proximal Humeral Internal Locking System (PHILOS) plate for a displaced surgical‑neck humerus fracture in an adult patient?

ORIF with PHILOS Plating for Surgical Neck Humerus Fracture: Step-by-Step Procedure

Preoperative Planning

Obtain adequate imaging including standard radiographs (AP, lateral, axillary views) and consider CT scanning to fully assess fracture pattern, comminution, and bone quality. 1, 2

• Assess for three-part versus four-part fracture configuration, tuberosity involvement, head-shaft disengagement, and presence of dislocation 3
• Evaluate bone quality particularly in elderly patients, as this affects fixation stability and complication risk 4
• Plan surgical approach and identify need for additional fixation techniques (cerclage wires, medial support screws) based on fracture pattern 5

Patient Positioning and Approach

Position the patient in beach chair position with the affected arm free to allow full manipulation during surgery. 1, 5

• Use a standard deltopectoral approach to access the proximal humerus 5
• Identify and protect the cephalic vein (typically retract laterally with deltoid) 5
• Preserve the anterior humeral circumflex vessels at the inferior border of subscapularis to maintain humeral head vascularity 5

Fracture Reduction

Perform minimal soft tissue dissection to preserve blood supply to the humeral head and fracture fragments, as this is critical for preventing avascular necrosis. 5, 4

• Identify and tag the rotator cuff tendons attached to the tuberosities with heavy sutures for manipulation 1, 5
• Reduce the humeral head to the shaft first, ensuring proper version and avoiding varus malalignment 2, 5
• Restore the medial calcar support by achieving anatomic reduction of the medial cortex 5
• Reduce the greater and lesser tuberosities to the head and shaft, ensuring proper height and rotation 1, 5
• Use cerclage wires (typically #2 or #5 non-absorbable suture or wire) through the rotator cuff insertions to provisionally hold tuberosity fragments if needed 5

PHILOS Plate Application

Position the PHILOS plate 5-8mm distal to the superior aspect of the greater tuberosity to avoid subacromial impingement. 2, 4

• The plate should sit on the lateral aspect of the proximal humerus, aligned with the humeral shaft axis 1, 5
• Ensure the plate is not positioned too anteriorly or posteriorly, as malposition increases impingement risk 4
• Temporarily fix the plate with a K-wire or non-locking screw in the shaft before inserting proximal screws 1

Screw Insertion Technique

Insert proximal locking screws into the humeral head in multiple directions to achieve angular stability, carefully measuring screw length to avoid articular penetration. 1, 2

• Place screws in divergent directions to maximize purchase in the humeral head 1, 5
• Measure screw length carefully and keep screws 5mm short of the articular surface to prevent secondary perforation 2, 4
• Insert an inferomedial oblique screw to support the medial calcar when medial cortical contact is insufficient 5
• Fill all available proximal holes with locking screws to maximize fixation strength, particularly in osteoporotic bone 1, 4
• Insert at least 3-4 bicortical locking screws in the humeral shaft 1, 5
• Verify screw position and length with fluoroscopy in multiple planes before final tightening 2, 4

Final Fixation Steps

Secure the tuberosities with additional sutures through the plate holes and rotator cuff, as this provides supplemental fixation beyond the screws alone. 1, 5

• Pass heavy non-absorbable sutures through the rotator cuff tendons and designated suture holes in the PHILOS plate 5
• Tie sutures to compress tuberosities against the plate and humeral head 5
• Confirm stable fixation by gently moving the arm through range of motion under direct visualization 1
• Obtain final fluoroscopic images in AP, lateral, and axillary views to confirm reduction and hardware position 2

Critical Technical Pitfalls to Avoid

Varus malreduction is the most common technical error and significantly compromises outcomes; ensure the head-shaft angle is anatomically restored (130-140 degrees). 2, 5

• Plate malposition (too superior) causes impingement in 3.6-18.5% of cases 2, 4
• Screws that are too long lead to secondary perforation in 3.6% of cases, often occurring months after surgery 2
• Inadequate medial calcar support increases risk of varus collapse and fixation failure 5
• Excessive soft tissue stripping increases avascular necrosis risk (reported 4.3-29.6%) 3, 4

Postoperative Protocol

Begin passive and active-assisted shoulder exercises on postoperative day 1-2, as early mobilization is essential for preventing stiffness while the locking plate provides stable fixation. 1, 5

• Initiate pendulum exercises and passive forward elevation immediately 5
• Progress to active-assisted exercises at 2 weeks 5
• Allow active abduction to 90 degrees at 2 weeks postoperatively 5
• Advance to full active range of motion at 6 weeks once early fracture healing is confirmed 1
• Expect radiographic union at mean of 10-12 weeks (range 8-24 weeks) 1, 5

Expected Outcomes and Complications

Patients can expect good functional outcomes with mean Constant scores of 66.5-79.5 points, though results are significantly better in three-part fractures compared to four-part fractures and in patients under 60 years old. 1, 5

• Reoperation rate is 23.6-29.6%, with stiffness being the most common reason requiring manipulation or capsular release 3, 4
• When reoperations for stiffness are excluded, implant survivorship is 90% at 10 years 3
• Avascular necrosis occurs in 4.3-29.6% of cases, with higher rates in four-part fractures 3, 5, 4
• Fixation failure/nonunion occurs in 2.4-6.8% of cases 2, 3
• Infection rate is low at 1.2% 2
• Age over 60 years and four-part fracture configuration significantly worsen functional outcomes 5