engleski

Late Monteggia: How to solve it?

1. Definition: Monteggia lesion is complex elbow/forearm injury which is consisting of radial head/capitellum dislocation with fracture of proximal or mid-shaft ulna. In immature ulnar bone injury may be a greenstick fracture or “simple plastic” deformation and could be unappreciated. Late (chronic) Monteggia lesion is a radiocapitellar dislocation that still persists 4 (four) weeks after injury due to unreduced primary lesions or missed diagnosis frequently after ulnar greenstick fracture or “plastic” deformation 2. History First description (1814.) of fracture/dislocation by Giovanni Battista MONTEGGIA (surgical pathologist, Milan, Italy). José Luis BADO (chief orthop. surg., Montevideo, Uruguay) in the year 1958. subdivided fracture in four types according to direction of ulnar fracture angulation and radial head dislocation, and he coined the term “Monteggia lesion”. Classification is published in English in the year 1967. 3. Aetiology and mechanics of injury. The aetiology is traumatic and mechanism is proposed by Tompkins (1971). The child falls on an outstretched arm with the elbow joint forced in hyperextension. The radial head is dislocated anteriorly by strong reflexive biceps contraction. The weight of the body is then solely on the ulna which breaks on anterior cortex by tension force. 4. Pathomorphology In acute Monteggia lesion annular ligament could be damaged and interposed within radio-ulnar joint as it is observed during surgical reduction. Occasionally, an intact annular ligament may be pulled over the radial head obstructing closed reduction. In chronic radial head dislocation pathologic changes of elbow joint were studied by Kim et al. (2002.). Dysplastic changes were observed in both congenital and posttraumatic group: ► large deformed radial head ; ► slender radial neck ; ► ulnar bowing ; ► radio- capitellar incongruence. These changes are likely to produce pain, limitation of motion, osteoarthrosis and disability in adulthood. 5. Classification. Bado classification of Monteggia lesion and equivalents (1958.) is the most accepted one in the literature. 6. Diagnosis In acute Monteggia lesion diagnosis of ulnar fracture is visible on good quality X-rays that include whole forearm with elbow and radio- carpal joints. Note: plastic ulnar deformation and greenstick fracture could be missed, especially in a busy ED (Gleeson & Beattie, J Acc & Emerg Med, 1994 ; Perron et al., Am J Emerg Med 2001). A high degree of suspicion is needed. Ulnar bow sign could be helpful as described by Lincoln & Mubarak (JPO 1994.). Deviation of the ulnar border from the reference line is shown on schematic drawing (A). Positive sign is deviation of more than 1 mm. A B Soft tissue part of Monteggia lesion could be overlooked by inexperienced physician, even if ulnar fracture is diagnosed. Another, radio- capitellar line is helpful to check normal radiocapitellar congruence. A true lateral X ray view of the elbow is needed. A line passing through centre of radial head and neck should extend directly through the centre of capitellum, regardless of the degree of elbow flexion or extension as it is shown on schematic drawing (B). Recently questioned by Ramirez et al. (JPO 2014) 7. Differential diagnosis a) Congenital dislocation of the radial head ● usually bilateral, posterior direction, X-ray features: radial head is convex, enlarged, irregular and eccentric ; capitellum is flattened. b) Pathological ● Neuromuscular: Erb’s palsy ; cerebral palsy, arthrogryposis (amyoplasia) ; ● Hyperlaxity syndromes: osteogenesis imperfecta ; ● Tumors like conditions: multiple exostosis, Morbus Ollier. 8. Treatment (for delayed diagnosis = chronic cases) ● Indications (Papandrea & Waters, 2000 ; Wilkins 2002.): ►progressive radio-capitellar subluxation or dislocation ; ►progressive valgus deformity ; ►limited range of elbow or forearm motion ; ►pain at the malaligned radiocapitellar or radioulnar joint ; ►age less than 12 years ; ►concave radial head (convex, deformed radial head would not produce congruous radio- capitellar joint) ; ►long time span form original injury is not a limitation for surgery if above conditions are fulfilled. ● Treatment options: ►watchful waiting ; ►open radio-capitellar reduction+ ulnar osteotomy (plate & screws vs. Ex. Fix) ►open radio-capitellar reduction + ulnar osteotomy + annular ligament reconstruction: a) Bell-Tawse procedure w/ a slip of triceps tendon b) Hui et. al. (JPO, 2005.) w/ forearm fascia Controversy: - ulnar osteotomy + overcorrection (YES or NO?) - addition of trans-capitellar K-wire fixation (YES or NO?) 9. Complications Reconstruction of chronic Monteggia lesion in children may be associated with numerous complications (Rodgers et al., JBJS /Am/ 1996 ; Đapić et al. 2004.): 1) nerve lesions - radial and ulnar nerve ; 2) malunion of ulnar shaft ; 3) residual radiocapitellar subluxation ; 4) non-union at ulnar osteotomy site ; 5) ulnar fracture below the osteotomy site ; 6) compartment syndrome. 10. Conclusion Late reconstructive procedures of chronic Monteggia lesion should not be attempted before learning the basic principles that need to be addressed. A thorough study of the possible complications is mandatory before surgery is performed. Current best possible treatment for anterior lesion (Bado type I) is ulnar flexion angulation (with elongation, if necessary) ; fixation with plate/screws or external fixation (recent reports). Open reduction of radio-capitelar joint, if necessary

Chronic Monteggia lesion ; late treatment, surgery

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