Patella Sleeve Fracture

Introduction

Sleeve fracture occurs between the cartilage "sleeve" and main part of the patella and ossific nucleus
Epidemiology
- occurs most commonly in children 8 to 12 yearsof age
Pathophysiology
- disruption can occur distally, laterally, or proximally

Anatomy

Ossification
- does not begin until 3 to5 years of age.
- most patellar fractures occur in adolescentswhen ossification is nearly complete

Presentation

Physical exam
- local tenderness
- soft-tissue swelling
- hemarthrosis ofthe knee joint
- a high-riding patellaimplies that the extensor mechanism has been disrupted

Imaging

Radiographs
- diagnosis may be missed because thedistal bony fragment is not readily discernible on radiographs
  - patella alta for distal fractures or patella baja for proximal fractures may be evident
MRI
- may be useful for diagnosing a sleevefracture when the diagnosis is not clear from the clinical andplain radiographic findings

Treatment

Nonoperative
- cylinder cast for 6 weeks
  - indications
    - nondisplaced
Operative
- open reduction and internal fixation
  - indications
    - displacement more than 2-3mm
  - technique
    - repair of the torn medial and lateral retinaculum along with the use of sutures through the cartilaginous and osseous portions of the patella often suffice
    - can be stabilizedusing modified tension band wiring around two longitudinallyplaced Kirschner wires

TAG

(OBQ09.77) A 10-year-old female presents to the ED complaining of anterior knee pain after a fall from her bicycle. Exam reveals ecchymosis and swelling over the patella and an extensor lag. A lateral radiograph is shown in Figure A. What is the next step in treament? Topic

Review Topic

FIGURES: A

1. Open reduction and internal fixation
2. Quadraceps tendon repair
3. Cylinder cast
4. Knee aspiration
5. Reconstruction of the patella tendon

PREFERRED RESPONSE ▶

DISCUSSION: Patella sleeve fractures occur most commonly in children aged 8-12. This injury involves an avulsion of cartilage (and sometimes a small piece of bone) from the inferior pole of the patella. These fractures may be missed on plain radiographs if there is no obvious bony injury. Radiographs will typically show an effusion, patella alta, and possibly a bony avulsion. In uncertain cases, an MRI is useful to define the extent of injury. Treatment for displaced sleeve fractures involves open reduction and fixation of the injury to restore the extensor mechanism. The article by Zionts reviews the diagnosis and management of fractures about the distal femur, proximal tibia, and patella in children.

Illustrations: A

REFERENCES:

1. Zionts LE: Fractures around the knee in children. J Am Acad Orthop Surg 2002;10:345- 355 PMID:12374485 (Link to Abstract)

2. Sponseller PD, Stanitski CL: Fractures and dislocations about the knee, in Beaty JH, Kasser JR: Rockwood and Wilkins’ Fractures in Children, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1029-1033

Question Authors:

Robert Boykin MD, Eric Shirley MD,

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Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Sponseller PD, Stanitski CL: Fractures and dislocations about the knee, in Beaty JH, Kasser JR: Rockwood and Wilkins’ Fractures in Children, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1029-1033

Undefined

Zionts LE: Fractures around the knee in children. J Am Acad Orthop Surg 2002;10:345- 355 PMID:12374485 (Link to Abstract)

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