HAND (2009) 4:167–172 DOI 10.1007/s11552-008-9152-9 CASE REPORTS Persistent Posterior Interosseous Nerve Palsy Associated with a Chronic Type I Monteggia Fracture-Dislocation in a Child: A Case Report and Review of the Literature David E. Ruchelsman & Michele Pasqualetto & Andrew E. Price & John A. I. Grossman Received: 29 September 2008 /Accepted: 12 November 2008 /Published online: 4 December 2008 # American Association for Hand Surgery 2008 Abstract We present a rare case of persistent complete Keywords Pediatric . Monteggia fracture-dislocation . posterior interosseous nerve palsy associated with a Radial head dislocation . Posterior interosseous nerve palsy. chronictypeIMonteggiaelbowfracture-dislocation Elbow trauma consisting of anterior dislocation of the radial head and malunion of the ulna in an 8-year-old child requiring surgical treatment. Posterior interosseous nerve neuro- Introduction praxia following acute Monteggia injury patterns about the elbow has been described and is thought to be Chronic complete posterior interosseous nerve (PIN) palsy secondary to traction or direct trauma. The condition is a recognized but uncommon sequela of the type I typically resolves following successful closed reduction of Monteggia elbow fracture-dislocation in children. This the radial head. This report describes combined treatment report describes combined radial nerve exploration with of the nerve and skeletal injury for the chronic type I PIN neurolysis and surgical reconstruction of a chronic type Monteggia injury. The literature is reviewed, and diag- I Monteggia injury in a child. PIN subluxation followed by nostic challenges with and treatment options for chronic chronic compression at the proximal radioulnar joint Monteggia fracture-dislocations in children are discussed. (PRUJ), radiocapitellar joint (RCJ), and arcade of Froshe may be suspected in this rare clinical scenario. Case Report Investigation conducted at NYU Hospital for Joint Diseases, New York, NY No benefits in any form have been received or will be received from a An 8-year-old right-hand-dominant boy presented to our commercial party related directly or indirectly to the subject of this institution approximately 3 months after sustaining an article. injury to his left elbow following a fall on ice. His elbow D. E. Ruchelsman (*) : A. E. Price : J. A. I. Grossman injury was initially treated at another institution with cast Department of Orthopaedic Surgery, immobilization for 6 weeks. Following cast removal, the NYU Hospital for Joint Diseases, mother complained of persistent deformity of the left elbow 301 East 17th Street, 14th Floor, New York, NY 10003, USA and weakness of the hand. Radiographic evaluation e-mail: [email protected] revealed evidence of a chronic type I Monteggia fracture- J. A. I. Grossman dislocation with persistent anterior dislocation of the radial e-mail: [email protected] head and malunion of the ulna (Fig. 1). Clinical examina- tion was consistent with a complete posterior interosseous M. Pasqualetto nerve palsy. Digital and thumb extensions were graded 1/5, Department of Occupational Therapy, NYU Hospital for Joint Diseases, and there were no palpable contractions of the extensor 301 East 17th Street, 14th Floor, carpi radialis brevis or extensor carpi ulnaris. Sensory New York, NY 10003, USA examination in the radial nerve distribution was unremark- 168 HAND (2009) 4:167–172 Fig. 1 Preoperative anteropos- terior (a) and lateral (b) elbow radiographs demonstrate the chronic type I Monteggia fracture-dislocation with persistent anterior dislocation of the radial head and malunion of the ulna. able. Electrodiagnostic studies confirmed a left PIN in order to obtain anatomic reduction of the radial head. neuropathy. Motor nerve conduction studies failed to record Annular ligament reconstruction was performed utilizing a compound muscle action potentials in the left radial nerve proximally based strip of periosteum harvested from the forearm–elbow segment, and electromyography of PIN- proximal ulna. The annular ligament reconstruction was innervated muscles demonstrated membrane instability and tensioned to allow for smooth pronation and supination no motor units. Sensory nerve action potentials of the left without any dislocation of the radial head throughout a full radial nerve revealed normal amplitudes and conduction range of motion. Transcapitellar fixation of the reduced velocities. A physical therapy program was initiated, and radial head was performed with a 3/32″ smooth Steinman the patient was followed at monthly intervals. Repeat pin to maintain the radial head reduced against the clinical and electrodiagnostic evaluations at 3 months capitellum and reduce stress on the soft tissue reconstruc- following the initial study revealed no interval change. tion. The lateral capsule was repaired and the incision At 9 months following the original injury, the patient closed in layers. A long arm cast with the forearm in full underwent exploration of the left PIN and reconstruction of supination and the elbow maintained in 90° of flexion was the chronic Monteggia fracture-dislocation. An anterolateral applied. Electrical muscle stimulation to the wrist and approach was utilized. The radial nerve was first identified extrinsic thumb and digital extensors was immediately between the brachialis and brachioradialis at its emergence initiated through a window in the cast. The postoperative from the lateral intermuscular septum. Distally, the bifurca- course was uneventful. tion was identified, and the PIN was explored to the level of Serial postoperative radiographs demonstrated mainte- the arcade of Froshe. The radial head was found anteriorly nance of reduction of the radiocapitellar relationship, and at dislocated between the superficial radial nerve and PIN. The 6 weeks postoperatively the long arm cast and Steinman pin PIN was subluxed posterior to the radial head and encased in were removed. Radiographic evidence of delayed union thick scar adherent to the capsules of the proximal radioulnar was seen at 6 months postoperatively, and the patient and radiocapitellar joints (Fig. 2). Chronic compressive underwent revision surgery with plate fixation. At 6 months changes of the nerve and epineural fibrosis were visualized following the revision surgery, radiographs revealed three at these sites of capsular cicatrix and at the arcade of Froshe. cortices of osseous healing at the ulnar osteotomy site with Intraoperative neurophysiologic recordings were attempted, maintenance of the radiocapitellar relationship (Fig. 3). The but given the time elapsed since the initial injury, recordable patient is currently pain free at the elbow, forearm, and distal responses from the PIN-innervated muscles were not wrist, and abundant callus is palpable along the subcutane- obtained, and the anatomy in this case did not allow studying ous border of the ulna. At 12 months following neurolysis the neuroma in continuity. A complete microsurgical of the radial nerve, the patient demonstrates excellent neurolysis was performed (Fig. 2). clinical evidence of return of function of the posterior Next, the Kocher interval between the extensor carpi interosseous nerve. There is full active wrist extension ulnaris and anconeus was utilized to expose the radio- without deviation and full active digital metacarpal– capitellar joint. Reduction of the radiocapitellar joint was phalangeal joint extension with mild residual weakness of initially prevented by the interposed capsule, torn annular the extensor pollicus longus and abductor pollicus longus ligament, and scar tissue, and these soft tissues were (Medical Research Council [MRC] 4/5). Clinical examina- resected. A corrective ulnar osteotomy was then performed tion further demonstrated full active ulnohumeral flexion HAND (2009) 4:167–172 169 and extension. Active forearm rotation consisted of full supination and 30° of pronation. Discussion In 1814, Monteggia first described the association of radial head dislocation with a concomitant fracture of the ulna [25]. Several classifications [2, 10, 23, 25, 41] have been presented for Monteggia fracture-dislocations. Bado’s clas- sification [2] is well established in clinical orthopaedic practice, subdividing Monteggia fracture-dislocations into true Monteggia lesions (types I–IV) and equivalent lesions. Bado type I lesions, with anterior dislocation of the radial head and concomitant anterior angulation of the ulnar diaphyseal fracture, are the most common Monteggia fracture-dislocations in the pediatric population and consti- tute approximately 70% of Monteggia fracture-dislocations [6, 10, 12, 23, 27, 20, 30, 31, 41]. In the presented case, it is unclear if the radial head dislocation was appreciated and closed reduction achieved at the initial treating institution. Orthogonal radiographs obtained 3 months following the initial injury revealed chronic anterior dislocation of the radial head and malunion of the ulna. The high incidence of redislocation of the radial head after either spontaneous [21, 40] or closed reduction [10, 29] despite cast immobilization requires serial ante- roposterior and lateral radiographs of the elbow be obtained and the radiocapitellar relationship evaluated with the radiocapitellar line on each film. Operative treatment of Monteggia fracture-dislocations is necessary when closed reduction is unsuccessful in patients seen more than a month after the injury (i.e., chronic radial head dislocation). Chronic