Ortho Case of the Week – Knee ANSWERS

Time to study hard to break through that plateau!

Case 1: A 45 year-old male fell onto his left knee 10 feet while descending from a ladder.

1. What is the diagnosis based on the x-ray above?

Comminuted patella fracture, with associated proximal retraction of the proximal fragment.

2. How should a patellar fracture be treated in the emergency department?

If extensor mechanism/straight leg raise function is intact and there is minimal displacement (<3mm), apply a knee immobilizer, WBAT, and outpatient ortho follow-up.

If extensor mechanism not fully intact or there is displacement of >3mm, consult ortho for ORIF.

3. What congenital anomaly may be confused for a patellar fracture.

Bipartite patella. Present in approximately 2-3% of the population. Characteristic superolateral position, present bilaterally in 50% of cases. Smooth, regular boarders. Caused by failure of the secondary ossific nucleus to unite.

4. Clinically, how would you differentiate from a quadriceps tendon rupture versus a patellar tendon rupture?

Quadriceps tendon ruptures: low-riding patellar with palpable defect above

Patellar tendon ruptures: high-riding patella with palpable defect below

5. What is the treatment for a quadriceps versus a patellar tendon rupture?

For complete tears, both are treated with a knee immobilizer locked in extension, WBAT, and close ortho follow-up for likely surgery within 7 days.

Partial ruptures (with an intact extensor mechanism) should be treated the same with a knee immobilizer locked in extension and WBAT to prevent progression to a complete rupture but may not require operative intervention.

Case 2: A 26-year-old male sustains a right knee injury after falling from the roof of a two story house.

1. What is your full read of the plain films above?

Depressed comminuted fracture of the lateral tibial plateau extending into the intercondylar eminence (Schatzker type II tibial plateau fracture). Fracture of the head and neck of the proximal fibula.

Here is a CT of the same patient: (link to full scrollable CT)

2. What are associated injuries and complications from tibial plateau fractures?

• Lateral plateau fractures are associated with ACL/MCL injuries.
• Medial plateau fractures are associated with PCL and LCL injuries.
• High risk of compartment syndrome
• Segond fractures (avulsion fracture of margin of lateral tibial plateau just below joint line) are associated with ACL tears in 75-100% of cases and are often associated with meniscal injuries.

Source: Orthobullets

3. What is the treatment of a tibial plateau fracture and how might it vary based on injury pattern?

Treatment is with a knee immobilizer locked in extension, non-weight bearing, and ortho follow up within 7 days.

Indications for expedited referral within 48 hours:

• Significant displacement or depression
• Suspected or documented ligamentous injury

Indications for outpatient surgery:

• Articular stepoff > 3mm
• Condylar widening > 5mm
• Varus/valgus instability
• All medial plateau fractures
• All bicondylar fractures

Admission for open fractures, compartment syndrome, or those with neuromuscular compromise.

Schatzker classification of tibial plateau fractures. As an FYI, not for memorization.

Source: WikEM

References:
https://wikem.org/wiki/Tibial_plateau_fracture
https://www.orthobullets.com/trauma/1044/tibial-plateau-fractures
https://radiopaedia.org/cases/schatzker-type-ii-tibial-plateau-fracture?lang=us
https://wikem.org/wiki/Patella_fracture
https://radiopaedia.org/cases/patella-fracture-10?lang=us
https://www.orthobullets.com/trauma/1042/patella-fracture
https://www.orthobullets.com/knee-and-sports/3023/quadriceps-tendon-rupture
https://www.orthobullets.com/knee-and-sports/3024/patella-tendon-rupture
https://www.orthobullets.com/trauma/1004/open-fractures-management