A 6-week-old boy is brought for routine examination at his pediatrician’s office. The patient was born at 39 weeks to a 26-year-old G1P1 mother by normal vaginal delivery. External cephalic version was performed successfully at 37 weeks for breech presentation. Pregnancy was complicated by gestational diabetes that was well-controlled with insulin. The patient’s maternal grandmother has early onset osteoporosis. On physical examination, the left hip dislocates posteriorly with adduction and depression of a flexed femur. An ultrasound is obtained that reveals left acetabular dysplasia and a dislocated left femur. Which of the following is the next best step in management?

Closed reduction and spica casting

Open reduction and femoral osteotomy

A 69-year-old woman presents with pain in her hip and groin. She states that the pain is present in the morning, and by the end of the day it is nearly unbearable. Her past medical history is notable for a treated episode of acute renal failure, diabetes mellitus, obesity, and hypertension. Her current medications include losartan, metformin, insulin, and ibuprofen. The patient recently started taking high doses of vitamin D as she believes that it could help her symptoms. She also states that she recently fell off the treadmill while exercising at the gym. On physical exam you note an obese woman. There is pain, decreased range of motion, and crepitus on physical exam of her right hip. The patient points to the areas that cause her pain stating that it is mostly over the groin. The patient's skin turgor reveals tenting. Radiography is ordered. Which of the following is most likely to be found on radiography?

Loss of joint space and osteophytes

Posterior displacement of the femoral head

A 17-year-old boy comes to the emergency department following an injury during football practice. He fell and landed on the lateral aspect of his right shoulder. He is holding his right arm supported by his left arm, with his right arm adducted against his side. He is tender to palpation directly over the middle third of his clavicle. Radiographs reveal a non-displaced fracture of the middle third of the clavicle. Which of the following is the most appropriate treatment at this time?

Open reduction and internal fixation with a compression plate

Open reduction and internal fixation with an intramedullary nail

Open reduction and internal fixation with lag screws

A 50-year-old manual laborer sustained a comminuted distal radius fracture treated with ORIF 3 months ago. Despite supervised hand therapy, he has persistent stiffness with 30-degree wrist extension (normal 70), weak grip strength at 40% of contralateral side, and visible muscle atrophy. He reports burning pain with light touch and keeps his hand wrapped in a sock. Skin appears mottled with decreased hair growth. He is applying for disability and has a pending lawsuit. Evaluate the clinical picture and appropriate next step.

Triple-phase bone scan and referral to pain management

EMG/NCS to evaluate for nerve injury

Psychiatric evaluation for malingering assessment

Repeat surgery for hardware removal and capsular release

Independent functional capacity evaluation

A 16-year-old basketball player presents with chronic anterior knee pain worse with jumping and kneeling. Examination shows tenderness at the inferior pole of the patella and pain with resisted knee extension. X-ray shows elongation and fragmentation of the inferior patellar pole. He has failed 6 months of physical therapy, activity modification, and NSAIDs. His AAU season starts in 6 weeks and a college scout will be attending. His parents want definitive treatment. Evaluate the management approach balancing medical and contextual factors.

Recommend season withdrawal, continued conservative management for 6 more months

Corticosteroid injection to allow play through season with surgery after

Arthroscopic excision of inferior pole fragments allowing return to play in 4 weeks

Open excision of ossicle with patellar tendon repair, 4-6 month recovery

PRP injection series with continued play and close monitoring

Internal fixation methods for USMLE Step 1: High-Yield Surgery Lessons

🛠️ Core Principles - The Carpenter's Rules

The four foundational AO (Arbeitsgemeinschaft für Osteosynthesefragen) principles guide all internal fixation procedures, ensuring a biological environment for healing. 📌 Mnemonic: Anatomic Reduction, Stable Fixation, Blood Supply, Mobilization.

$Internal fixation of bone fracture with plate and screws$

⭐ The choice of stability dictates healing type. Absolute stability (e.g., compression plating) leads to primary bone healing (direct osteonal remodeling, no callus). Relative stability (e.g., IM nailing) allows micromotion, promoting secondary bone healing (endochondral ossification via callus).

🛠️ Management - The Ortho Toolkit

Internal fixation aims to achieve anatomical reduction and stable fixation to allow for early mobilization. The choice of implant depends on fracture pattern, location, and bone quality.

Decision Framework for Fixation

Internal Fixation Methods: Screws, Wires, and Rods

Device	Biomechanical Principle	Common Indications
Screws	Interfragmentary Compression	Fix small fragments, attach plates
Plates	Buttress, Neutralization, Bridging	Periarticular, comminuted fractures
IM Nails	Internal Splinting (Load-Sharing)	Long bone shaft fractures (femur, tibia)
K-wires	Provisional or definitive fixation	Hand/foot, pediatric fractures
Tension Band	Converts distraction to compression	Olecranon, patella fractures

💡 Locking Plates: Screws lock into the plate, creating a fixed-angle construct. This is crucial for improved stability in osteoporotic bone or comminuted fractures.

🔩 Complications - When Screws Go Loose

Aseptic Loosening: Most common cause of late failure.
- Micromotion at bone-implant interface → fibrous tissue ingrowth.
- Wear debris (polyethylene, metal) → macrophage activation → osteolysis.
Implant Fatigue/Fracture: Occurs when cyclical loading exceeds the implant's endurance limit.
- Often secondary to nonunion; the implant bears the entire load instead of the healed bone.
Infection: Biofilm formation on hardware protects bacteria (e.g., S. aureus).
- ⚠️ Often requires implant removal for eradication.
- Presents with pain, erythema, drainage, elevated ESR/CRP.

⭐ A "radiolucent line" >2 mm wide at the bone-cement or bone-implant interface on X-ray is a key sign of loosening.

X-ray: Radiolucent lines around orthopedic screw

⚡ High‑Yield Points - Biggest Takeaways

Internal fixation aims for anatomic reduction and stability, promoting primary (direct) bone healing with minimal callus.

Screws provide interfragmentary compression, often using a lag technique (overdrilling the near cortex).

Plates offer absolute stability (e.g., compression, buttress) for articular and metaphyseal fractures.

Intramedullary (IM) nails are load-sharing devices, ideal for diaphyseal fractures of the femur and tibia, allowing early weight-bearing.

Tension band wiring converts tensile forces to compression, classic for patella and olecranon fractures.

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