PERILUNATE AND LUNATE DISLOCATIONS

Transcription

1 PERILUNATE AND LUNATE DISLOCATIONS Rebecca Morris Advanced Practitioner Plain Film Reporting March 2011

2 Perilunate and Lunate dislocations Introduction Definition Anatomy Clinical presentation Mechanism of Injury Radiographic signs Treatment/Imaging

3 Perilunate and Lunate dislocations Range of ligamentous injuries High Impact Young men Associated with scaphoid fractures Uncommon Injuries, 10% of all carpal injuries Long term complications Can be difficult to diagnose

4 Clinical Presentation Pain, swelling and decreased ROM Possible median nerve signs Subtle deformity Other injuries may detract from wrist injury

5 Anatomy Complex anatomy prone to injury Proximal Row allows most of the movement Distal Row Stabilises

6 What is a perilunate dislocation? Whole of the carpus apart from lunate is dislocated posteriorly Lunate and radius remain in articulation

7 What is a lunate dislocation? Lunate dislocates anteriorly Radius and capitate remain in a straight line Concavity of lunate is empty

8 Ligaments Intrinsic Link adjacent carpal bones. Extrinsic Link radius/ulna to carpus. Interosseous allow carpal bones to rotate in respect to one another.

9 Dorsal and Volar Ligaments Space of Poirier Area of Weakness between Volar radiocapitate and Volar radiotriqetral ligaments. Greenspan 2004

10 Mechanism of injury Axial force to dorsiflexed, ulna deviated wrist.

11 Stages of perilunate dislocations (Mayfield 2005) 1. Radioscaphoidcapitate ligament and scapholunate interosseous ligament rupture ( T T sign) 2. Dislocation of capitolunate joint ( PLD) 3. Lunotriquetral interosseous ligament ruptures (Midcarpal dislocation) 4. Complete lunate dislocation

12 Radiographic signs In a study undertaken by Saunders 2007 PL injuries were missed in 25%? Why? Systematic approach to radiological analysis Nelson - Parallel lines Gilulas lines Triangular appearance of the lunate

13 Nelsons lines Lateral view most diagnostic of Perilunate and Lunate dislocations Rogers 2002 Rogers 2002

14 Gilulas lines Greenspan

15 Appearance of the lunate on the AP/DP view Lunate indicative of a lunate dislocation Greenspan 2004

16 Stage 1 Terry Thomas sign Indicative of scapholunate dissociation Tear of radioscaphoid, palmer radiocapitate, and scapholunate ligaments.

17 Stage 2 Perilunate dislocation Tear of radioscaphoid, palmer radiocapitate, scapholunate ligaments and radiocapitate ligaments

18 Stage 3 Midcarpal dislocation Tears of volar and dorsal radiotriquetral and ulnotriquetral ligaments.

19 Stage 4 lunate dislocation Most severe, lunate is without ligamentous structure. Tear of radiolunate fascicle of the dorsal radiocarpal ligament and of volar ligaments.

20 Imaging Plain film gold standard for diagnosis providing the images are good quality CT valuable for complex fracturedislocations or when PF indeterminate MR excellent for non ossessous structures MR arthrography supercedes conventional wrist arthrography Recent advances in CT Arthrography

21 Treatment Accurate Prompt Treatment - Carpus reduced in A&E to reduce nerve damage (if possible) Historically closed reduction only now ORIF advocated. Dorsal or Volar? K wires or screws? 6 weeks POP and 6 weeks splint.

22 Summary Understanding the complex injury patterns Systematic radiological analysis gilulas lines etc Diagnosis from PF, CT and MR useful for surgical planning Prompt accurate treatment fundamental in ensuring good recovery

23 References A Greenspan Orthopaedic imaging A practical Approach th edition Lippincott Herzberg et al Perilunate dislocations and fracture dislocations ; A multicenter study The journal of hand Surgery A pg Melone C et al Perilunate Injuries Repair by Dual Dorsal and Volar Approaches Hand Clinics Vol 16 No.3 Aug pg Murray P Perilunate Fracture Dislocations cited on 13/5/9 http;//emedicine.medscape.com/article/ Rogers L Radiology of Skeletal Trauma Churchill Livingstone 3 rd edition 2002 Saunder D et al Perilunate Injuries Orthopedic clinics of North America pg

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