Gissane Angle [aka *critical angle; critical angle of Gissane], like the Böhler angle, can be used to help determine the presence of a calcaneus fracture on a radiograph.
Angle measured on lateral foot radiograph formed by the intersection of the lines drawn along the downward (lateral border of the posterior facet) and the upward (anterior beak/process) of the calcaneal superior surface.
Normal range is variably reported between 105-145°. Similarly conjecture exists regarding abnormal angle associated with calcaneal fractures ranging from >130-145°
History of the Gissane angle
1946 – William Gissane (1898-1981) presented ‘Fractures of the Os Calcis’ at the October meeting of the British Orthopaedic Association in 1946.
The normal os calcis has a number of features on radiological examination which are important to an understanding of fracture anatomy. There is a strong and thick cortical strut extending on the upper and outer side from the front of the bone to the posterior margin of the posterior subtaloid joint. This strut is angled and the angle supports the sharp lateral spur of the talus. This angle, with the wedge just above it, is of considerable importance and has been termed the ‘crucial angle’Gissane (1947) quoted In: Essex-Lopresti (1952)
2006 – Knight et al found that although the Boehler’s angle is somewhat helpful, the critical angle of Gissane is not useful in diagnosing calcaneus fractures in the ED. Interrater reliability for Boehler’s angle was excellent, but for the critical angle of Gissane, very poor. Emergency physicians were 97.9% accurate in making the diagnosis by reviewing the plain films without the assistance of angle measurements.
The original description by Gissane is difficult to locate. Most of the literature reports on his presentation to the British Orthopaedic Association in 1946, without defining original radiographs.
Discrepancy between the normal angles of 105-135°; 120-145°; and 130-145°
- Lorenz Böhler (1885 – 1973) [Böhler angle]
- William Gissane (1898 – 1981) [Critical angle of Gissane]
- Peter Gordon Lawrence Essex-Lopresti (1916 – 1951)
- Critical angle
- Critical angle of Gissane
- Gissane W. Discussion on “Fractures of the os calcis” (Proceedings of the British Orthopaedic Association, 1946). J Bone Joint Surg Am 1947; 29: 254–255
- Essex-Lopresti P. The mechanism, reduction technique, and results in fractures of the OS calcis. British Journal of Surgery, 1953; 39(157): 395–419.
- Sanders R. Intra-articular fractures of the calcaneus: present state of the art. J Orthop Trauma. 1992; (2): 252-265.
- Knight JR, Gross EA, Bradley GH, Bay C, LoVecchio F. Boehler’s angle and the critical angle of Gissane are of limited use in diagnosing calcaneus fractures in the ED. The American Journal of Emergency Medicine, 2006; 24(4): 423–427
- Boyle MJ et al. The paediatric Bohler’s angle and crucial angle of Gissane: a case series. Journal of Orthopaedic Surgery and Research 2011, 6:2
- Arslan G, Yirgin IK, Tasguzen A. A measuremental approach to calcaneal fractures. Eur J Trauma Emerg Surg. 2014; 40(5): 593-9
- Busti AJ. Critical Angle of Gissane: How to Use in the Diagnosis of a Calcaneus Fracture. EBM Consult. 2015
- Gomez A, Cadogan M. Eponymythology of foot injuries. LITFL
- Cadogan M. Critical angle of Gissane. Eponym A Day. Instagram
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