4.8 Fractures and Orthopedic Trauma
Key Takeaways
- Hip fractures (femoral neck and intertrochanteric) are fixed with cannulated screws or a sliding hip screw (DHS); the CSFA must support the fracture table reduction and confirm lag screw position in the femoral head center on fluoroscopy.
- Shoulder fractures (proximal humerus) may require reverse total shoulder arthroplasty when the tuberosities are comminuted; the CSFA must prepare the glenoid baseplate and humeral stem.
- Distal radius (wrist) fractures are treated with volar locking plate fixation; the CSFA must protect the flexor tendons and the median nerve during plate placement.
- Ankle fractures (bimalleolar, trimalleolar) require anatomic reduction and lateral/medial malleolus screw or plate fixation; the syndesmotic screws must be placed with the ankle in dorsiflexion to restore the mortise.
- Pelvic and spinal fractures are high-energy injuries; the CSFA must be prepared for massive blood loss, pelvic packing, and external fixation, with cell saver and a massive transfusion protocol ready.
Fractures and the Surgical First Assistant
The CSFA content outline requires the candidate to apply advanced knowledge of pathophysiology and histology to the handling and manipulation of tissue for fractures of the hip, shoulder, wrist, ankle, and pelvis/spine. Orthopedic trauma introduces unique tissue-handling challenges: bone fragments are often sharp, the surrounding soft tissue envelope is compromised, and fixation hardware must be placed with precision under fluoroscopic guidance.
General Principles of Fracture Surgery
- Restore length, alignment, and rotation.
- Preserve the soft tissue envelope (biological fixation).
- Achieve stable fixation appropriate to the fracture pattern.
- Protect neurovascular structures during reduction and hardware placement.
- Confirm reduction with intraoperative fluoroscopy in at least two planes.
The CSFA's role includes supporting reduction, protecting soft tissues, passing hardware, and verifying imaging. The assistant must know the planned fixation strategy before incision so that the correct implants are available.
Hip Fractures
Femoral Neck Fractures (Garden I-IV). Intracapsular fractures compromise the femoral head blood supply (the medial femoral circumflex artery's retinacular branches). Undisplaced or valgus-impacted fractures (Garden I-II) in physiologically young patients are treated with cannulated screw fixation (usually three 6.5 mm or 7.3 mm screws in an inverted-triangle configuration). Displaced fractures in elderly patients (Garden III-IV) are treated with hemiarthroplasty or total hip arthroplasty.
Intertrochanteric Fractures. Extracapsular, vascular (heal reliably). Standard fixation is the Dynamic Hip Screw (DHS / sliding hip screw) with a side plate, or an intramedullary nail (IMHS). The CSFA must confirm that the lag screw is centered in the femoral head on both AP and lateral fluoroscopy, within 10 mm of subchondral bone, and that the Tip-Apex Distance (TAD) is less than 25 mm to minimize cut-out risk.
Fracture Table and Reduction. The patient is placed on a fracture table in supine with the unaffected leg flexed and abducted in a well-leg holder. The fractured leg is tractioned and internally rotated to reduce the fracture. The CSFA must verify the patient's perineal post is padded, that the foot is securely fixed, and that no pressure is on the contralateral leg.
Shoulder (Proximal Humerus) Fractures
Three- and four-part fractures in elderly patients with comminuted tuberosities are increasingly treated with reverse total shoulder arthroplasty (rTSA). The CSFA must:
- Prepare the glenoid baseplate (central screw + peripheral locking screws).
- Help the surgeon identify the axillary nerve on the undersurface of the deltoid.
- Support tuberosity repair with non-absorbable sutures through the humeral stem's fin.
- Confirm that the humeral trial reduces without anterior instability.
Younger patients with reducible fractures may undergo open reduction and internal fixation (ORIF) with a locking proximal humerus plate. The CSFA must protect the axillary nerve at the inferior border of the subscapularis and the bicipital tendon during plate placement along the lateral humerus.
Wrist (Distal Radius) Fractures
Volar locking plate fixation is the standard for unstable distal radius fractures. The volar approach (Henry's) is used, retracting the flexor carpi radialis (FCR) tendon radially and the median nerve/ flexor tendons ulnarly. The flexor pollicis longus (FPL) is lifted off the pronator quadratus, which is incised to expose the volar distal radius.
Critical Landmarks:
- The watershed line on the volar distal radius marks the distal limit of plate placement; a plate placed distal to this line will irritate the flexor tendons.
- The brachioradialis tendon is released from the radial styloid to aid reduction.
CSFA Duties:
- Maintain retraction of the FCR and median nerve without compression.
- Help confirm distal screw placement does not penetrate the dorsal cortex (visible on lateral fluoroscopy).
- Keep K-wires available for provisional fixation before plate application.
Ankle Fractures
Bimalleolar and Trimalleolar Fractures. Require anatomic reduction and internal fixation. The lateral malleolus is fixed first with a plate or lag screw, restoring fibular length. The medial malleolus is fixed with two 4.0 mm partially threaded cannulated screws or a tension band. The posterior malleolus, if >25% of the articular surface, is fixed with anterior-to-posterior lag screws.
Syndesmotic Fixation. If the syndesmosis is disrupted, a 3.5 mm cortical screw is placed through both fibular and tibial cortices (tricortical), 2-3 cm above the plafond, with the ankle in dorsiflexion to ensure the widest part of the talar dome is captured and the mortise is not over-compressed.
CSFA Duties:
- Support reduction with a periarticular clamp (e.g., Weber) while screws are placed.
- Confirm fluoroscopy shows a symmetric mortise (no talar tilt, equal medial and superior clear spaces).
- Protect the saphenous vein and superficial peroneal nerve during lateral incision.
Pelvic and Spine Fractures
Pelvic Ring Fractures. High-energy injuries (lateral compression, AP compression, vertical shear). The CSFA must anticipate massive blood loss from the presacral venous plexus and the internal iliac arterial system. For unstable patterns, a pelvic binder or external fixator is placed urgently; definitive fixation includes anterior (pubic rami) and posterior (sacroiliac joint or sacrum) plating or percutaneous sacroiliac screws. The CSFA must prepare the C-arm for inlet, outlet, and obturator outlet views.
Spinal Fractures. Burst fractures with canal compromise may require posterior spinal fusion with pedicle screw instrumentation. The CSFA must help identify the pedicle starting point (junction of the transverse process, superior articular facet, and pars interarticularis) and confirm screw trajectory on AP and lateral fluoroscopy. The dura and nerve roots must be protected with a Penfield or nerve root retractor during decompression.
Fracture Table Preparation Checklist
| Item | Verification |
|---|---|
| Fracture table with perineal post | Padded, centered, traction tested |
| C-arm | Covered with sterile drape, positioned for AP and lateral |
| Image intensifier technician | Briefed on required views |
| Cell saver / rapid infuser | Set up for major pelvic or femoral cases |
| Implant trays | Cannulated screws, DHS/IMHS, plates confirmed on preoperative plan |
Surgical Trap: In ankle fracture fixation, placement of a syndesmotic screw with the ankle in plantar flexion over-compresses the mortise at the narrowest talar dimension, causing loss of dorsiflexion postoperatively. Always confirm the ankle is in neutral dorsiflexion or slight dorsiflexion when the screw is tightened.
When assisting fixation of an intertrochanteric hip fracture with a Dynamic Hip Screw (DHS), which fluoroscopic measurement must the CSFA help the surgeon confirm to minimize the risk of lag screw cut-out from the femoral head?
During volar plating of a distal radius fracture, the surgeon asks the CSFA where the distal edge of the plate must not extend. Which anatomical landmark defines the distal limit of plate placement?
For an unstable ankle fracture with syndesmotic disruption, the CSFA must confirm the ankle is in which position when the syndesmotic screw is tightened to avoid over-compression of the mortise?