THE EXPERIENCE OF A SPECIALIST REFERRAL CENTRE

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1 Trauma Clinical outcome of nerve injuries associated with supracondylar fractures of the humerus in children THE EXPERIENCE OF A SPECIALIST REFERRAL CENTRE M. Ramachandran, R. Birch, D. M. Eastwood From The Royal National Orthopaedic Hospital, Stanmore, England Between 1998 and 2002, 37 neuropathies in 32 patients with a displaced supracondylar fracture of the humerus who were referred to a nerve injury unit were identified. There were 19 boys and 13 girls with a mean age of 7.9 years (3.6 to 11.3). A retrospective review of these injuries was performed. The ulnar nerve was injured in 19, the median nerve in ten and the radial nerve in eight cases. Fourteen neuropathies were noted at the initial presentation and 23 were diagnosed after treatment of the fracture. After referral, exploration of the nerve was planned for 13 patients. Surgery was later cancelled in three because of clinical recovery. Six patients underwent alone. Excision of neuroma and nerve grafting were performed in four. At follow-up, 26 patients had an excellent, five a good and one a fair outcome. " M. Ramachandran, MB, FRCS(Orth), Specialist Orthopaedic Registrar " D. M. Eastwood, MB, FRCS, Consultant Orthopaedic Surgeon " R. Birch, MChir, FRCS, Professor, Consultant Orthopaedic Surgeon The Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK. Correspondence should be sent to Miss D. M. Eastwood; DMEastwood@ btinternet.com 2006 British Editorial Society of Bone and Joint Surgery doi: / x.88b $2.00 J Bone Joint Surg [Br] 2006;88-B:90-4. Received 20 June 2005; Accepted after revision 26 July 2005 Neurological complications associated with supracondylar fractures of the humerus in children are well recognised. 1,2 The relative incidences of traumatic and iatrogenic nerve injuries associated with this fracture have been reported as being 12% to 20% 1,3,4 and 2% to 6%, 5,6 respectively. The radial and anterior interosseous nerves are thought to be those most commonly involved by the fracture itself 2,3,7 while iatrogenic damage most often affects the ulnar nerve Several studies have suggested that 86% to 100% of these nerve injuries are neurapraxias which resolve spontaneously within six months, with the mean time to recovery being between two and three months. 3,4,8,11 By contrast, other reports have noted inadequate recovery and the need for surgical intervention in selected cases. 1,6,9 Our aim was to report the referral pattern and the outcome of nerve injuries associated with supracondylar fractures of the humerus in children seen over a period of five years at a dedicated peripheral nerve injury unit in the UK. Patients and Methods The database of our peripheral nerve injury unit was reviewed to identify all patients under the age of 16 years who had been referred for the further management of a nerve injury associated with a supracondylar fracture of the humerus between January 1, 1998 and December 31, Children with other injuries to the elbow, such as condylar fractures and physeal injuries, were excluded from the study. We identified 32 patients with 32 fractures and 37 nerve injuries. There were 19 boys and 13 girls with a mean age at referral of 7.9 years (3.6 to 12.5; Table I). The mechanism of injury in 31 patients was a fall from a height. The remaining patient (case 18) had been the frontseat passenger in a car involved in a road-traffic accident. All the fractures were closed, displaced extension-type injuries. The fractures were classified using the Gartland classification at the referring hospital 12 (Table II), and this was confirmed, when possible at the first consultation in our unit. Eight of the 32 fractures were classified as Gartland type II and 24 as Gartland type III. At the referring hospital, two of the fractures had been treated by closed reduction and above-elbow casting, 20 by closed reduction and percutaneous cross Kirschner (K-) wire fixation with a mini-open medial approach to protect the ulnar nerve, and ten by formal open reduction and cross K- wire fixation. A lateral approach to the fracture had been used in nine of ten open reductions, with an anterior approach in the final case to allow concomitant exploration of a vascular injury. One further patient had an anterior incision for a delayed exploration for vascular compromise (Table I). The neural injuries were initially managed by observation at the treating hospital, and referred when inadequate recovery was noted. 90 THE JOURNAL OF BONE AND JOINT SURGERY

2 CLINICAL OUTCOME OF NERVE INJURIES ASSOCIATED WITH SUPRACONDYLAR FRACTURES OF THE HUMERUS IN CHILDREN 91 Table I. Details of the patients at the time of referral to the specialist unit Case Gender * Age at referral (yrs) Gartland grade 12 Initial treatment Associated injuries Nerve(s) injured Time noted 1 M 5.9 III CRPP None Ulnar Post-operative 2 M 9.4 III CRPP None Median Post-operative 3 F 6.4 III CRPP None Ulnar Post-operative 4 M 9.8 II CR None Ulnar Injury 5 M 11.3 II CRPP None Median Injury 6 M 10.2 III ORP None Ulnar Post-operative 7 F 9.5 III CRPP None Median Post-operative 8 M 5.9 III ORP None Ulnar, median Post-operative 9 F 7.3 III ORP None Ulnar Post-operative 10 F 9.8 III CRPP None Ulnar Post-operative 11 M 7.1 III CRPP None Median Post-operative 12 F 7.3 II CRPP None Ulnar Post-operative 13 M 5.0 II CRPP None Radial Injury 14 F 9.2 III ORP None Radial Post-operative 15 F 6.1 III CRPP None Ulnar Post-operative 16 M 6.5 III ORP Brachial artery entrapment fracture Ulnar, median Injury site freed at ORP 17 M 5.2 III CRPP None Ulnar Post-operative 18 M 12.5 III CRPP None Ulnar Injury 19 F 8.3 III ORP None Median Ulnar, radial Injury Post-operative 20 F 5.8 III CRPP None Median Injury 21 F 8.0 III CRPP None Ulnar Post-operative 22 M 3.6 III CRPP None Radial Injury 23 M 9.3 III CRPP None Radial Post-operative 24 M 10.4 II CR None Ulnar Injury 25 F 7.3 III ORP None Radial Injury 26 M 10.5 II CRPP None Ulnar Post-operative 27 M 5.8 III ORP None Radial Injury 28 M 6.8 II ORP None Ulnar Post-operative 29 F 10.8 III CRPP Brachial artery spasm on exploration Ulnar, median Post-operative by vascular surgeons prophylactic flexor compartment decompression 30 M 8.3 III ORP None Radial Post-operative 31 M 6.2 II CRPP None Median Injury 32 F 7.3 III CRPP None Ulnar Injury * F, female; M, male CR, closed reduction and above-elbow cast; CRPP, closed reduction and percutaneous fixation; ORP, open reduction and fixation All children presented to our unit within three months of the injury. The indications for operative intervention were either a complete degenerative on neurophysiological studies or failure of the anticipated clinical recovery. The operative findings and details of the surgical procedure were recorded. Post-operative follow-up was carried out at six weeks, three months and subsequently every three months until full recovery. The clinical outcome at the last follow-up was assessed according to the criteria of Birch, Bonney and Wynn Parry 13 and graded as excellent, good, fair or poor (Table III). Results Clinical details are shown in Table I. Nineteen (51.4%) of the referred nerve injuries involved the ulnar, ten (27%) the median and eight (21.6%) the radial nerve. Out of 37 neuropathies 14 (37.8%) were directly related to the injury itself and were noted at the time of presentation. The remaining 23 (62.2%) were diagnosed after reduction and fixation. Of the 14 neuropathies related to the injury, five were to the ulnar, five to the median and four to the radial Table II. The Gartland 12 classification of extensiontype supracondylar fractures Type I II III Displacement Undisplaced Displaced (with intact posterior cortex) Displaced (no cortical contact) nerve. Of the 23 diagnosed after initial intervention, 14 were to the ulnar, five to the median and four to the radial nerve. Nine of the 14 (64%) injuries to the ulnar nerve were associated with closed reduction and percutaneous pin fixation of the fracture. There were no cases of compartment syndrome. In two of the 32 patients, there had been a suggestion of vascular compromise. One case was noted at presentation and an anterior approach was used with crossed K-wire fixation of the fracture (case 16) and in the other, vascular compromise was noted after closed reduction and percutaneous fixation and an anterior approach to the vessels was performed 24 hours later (case 29). VOL. 87-B, No. 1, JANUARY 2006

3 92 M. RAMACHANDRAN, R. BIRCH, D. M. EASTWOOD Table III. Grading of the results after nerve injury in the forearm according to the criteria of Birch et al 13 Grade Motor function Sensation * Comments Excellent MRC grade 5 Normal Normal Good MRC grade 4+ Minimal alteration in all modalities Essentially normal Fair MRC grade 3 Decreased texture recognition and two-point discrimination Skin atrophy, brittle nails and possible growth disturbance Poor MRC grade less than 3 Pain As above * the presence of pain or painful sensations automatically downgrades the result to poor MRC, Medical Research Council Table IV. Details of the 13 patients in whom surgery was planned Case Nerve injured Progress 1 Ulnar Complete degenerative 2 Median Complete degenerative 3 Ulnar Complete degenerative 4 Ulnar Complete degenerative 7 Median Complete degenerative 9 Ulnar Inadequate recovery after initial injury noted postoperatively 10 Ulnar Complete degenerative 12 Ulnar Complete degenerative 13 Radial Complete degenerative 14 Radial Complete degenerative 22 Radial Complete degenerative 23 Radial Complete degenerative 26 Ulnar Complete degenerative Findings at operation (if performed) Source of nerve graft (if necessary) * Time to recovery from surgery or injury (mths) Outcome Neuroma related to site of wiring; grafting MCNF 3 (from grafting) Excellent Neuroma surrounded by MCNF 3 (from grafting) Excellent scar tissue; grafting 6 (from ) Good Surgery cancelled on admission 6 (from injury) Excellent Nerve in scar tissue in 3 (from ) Good cubital tunnel; Surgery cancelled on admission 9 (from injury) Excellent Surgery cancelled on admission 6 (from injury) Excellent Nerve entrapment, laceration and gapping at fracture site; grafting Neuroma within fracture site; grafting Nerve in scar tissue in cubital tunnel; MCNF 6 (from grafting) Excellent SRN 24 (from grafting) Fair * MCNF, medial cutaneous nerve of forearm; SRN, superficial radial nerve lack of thumb extension requiring transfer of palmaris longus to extensor pollicis longus 17 months after grafting Spontaneous neurological recovery occurred in 19 patients (24 nerves) at a mean of 7.7 months (3 to 15) after injury, with 16 patients having an excellent and three a good outcome. Operative intervention was planned for 13 patients (13 nerves) either because of a complete degenerative or because of clinical failure of recovery (Table IV). In three, surgery was cancelled on the day of admission as there were signs of recovery of nerve function and two of these recovered fully by six months from the time of the injury, while the third recovered by nine months. All had an excellent outcome. Ten patients underwent exploration of their nerve s at a mean of 7.7 months (6 to 9) after injury. At exploration, nine nerves were noted to be in continuity. A nerve stimulator was used to assess functional continuity across the site of the injury. When distal function was noted with proximal stimulation, conservative surgery was performed. An external was performed in six ulnar nerves, four were trapped within callus and two in fibrous scar tissue within the cubital tunnel. Four patients had an excellent and two had a good outcome. The remaining four nerve s (two radial, one ulnar and one median) required nerve grafting to establish functional continuity, three because of the formation of a neuroma with no distal response to proximal stimulation, and one because of laceration, retraction of nerve ends and resultant gap. The medial cutaneous nerve of the forearm was used as the donor in three patients, and the superficial radial nerve in one. There were no operative complications. Of these four patients, three had an excellent, and one a fair outcome. The last child did not regain extension of the thumb after a radial nerve injury treated by superficial THE JOURNAL OF BONE AND JOINT SURGERY

4 CLINICAL OUTCOME OF NERVE INJURIES ASSOCIATED WITH SUPRACONDYLAR FRACTURES OF THE HUMERUS IN CHILDREN 93 radial nerve grafting. She subsequently underwent transfer of palmaris longus to extensor pollicis longus. Although 50% (four of eight) of the s of the radial nerve occurred in association with a lateral approach for an open reduction only two of the four were iatrogenic. All four recovered spontaneously although surgery was planned in two. Overall, 26 patients (81.3%) had an excellent, five (15.6%) a good and one (3.1%) a fair outcome. In 13 patients 14 s were noted at presentation of the fracture; two of these patients subsequently underwent surgical exploration. Of the 13 patients, 12 (92%) had an excellent outcome. Twenty-three nerve s in 20 patients were classified as iatropathic in that the nerve injury was noted after intervention either in terms of a manipulation or percutaneous fixation or open reduction. One patient (case 19) had a of the median nerve identified at presentation and injury to the ulnar and radial nerves after open reduction and percutaneous fixation. Eight patients (40%) with iatropathic injuries underwent a surgical procedure. Of the 20 patients 15 (75%) had an excellent outcome. Discussion Nerve injuries after supracondylar humeral fractures occur primarily due to tenting or entrapment of the nerve on the sharp proximal humeral fragment, while iatrogenic injuries occur either during closed manipulation or percutaneous fixation of the fracture fragments or occasionally during open procedures. 8,9,14 The median or anterior interosseous nerves are most commonly damaged by extension-type injuries, while the less common flexion-type injuries affect the ulnar nerve more often It has been reported that iatrogenic injuries most commonly affect the ulnar nerve, with percutaneous crossed K- wire fixation being associated with the highest risk of injury. 10 In a smaller study by Green et al, 18 only one case of neurapraxia of the ulnar nerve was identified in 65 patients treated in this way. This study which was based on late referrals to a specialist nerve injury unit similarly showed a relationship between s of the ulnar nerve and closed reduction and percutaneous crossed K-wire fixation. Our unit accepts referrals from all over the country. We cannot comment on the true incidence of supracondylar-associated neural injuries since referrals were only made to us by the treating hospitals when the initial period of observation had failed to show recovery. Therefore, transient neurapraxias, whether traumatic or iatrogenic in origin, are not included in our figures. This may explain the low incidence of anterior interosseous nerve s in our study. In addition, we assume that some neural injuries would have been treated locally by other appropriate units. Most studies in the orthopaedic literature have reported a good to excellent prognosis for nerve injuries associated with supracondylar fractures in children. 3,4,8,11 A few have emphasised the need for surgical intervention in selected cases. 1,6,9 Culp et al 1 reported 18 nerve injuries in a retrospective review of 101 displaced extension-type supracondylar fractures. They explored nine cases when there was no clinical or electromyographic evidence of return of function at a mean 7.5 months after injury; eight s were in continuity, with nerve function recovering well after. One complete laceration of the radial nerve, however, did not recover even after grafting and underwent tendon transfers. Birch and Achan 6 reported 118 cases of repaired nerve s associated with fractures and dislocations at the elbow displayed at operation, of which 91 were in conjunction with supracondylar fractures. Of these, 43 involved the median, 35 the ulnar and 13 the radial nerve. Seven cases were iatropathic, although it was unclear if any or all of these were related to the supracondylar fractures. They specified that 22 of the 91 injured nerves associated with supracondylar fractures were found to be entrapped within the fracture or impaled on a bone spike, while the remainder were compressed by swelling or fibrosis at or distal to the fracture, the latter showing uniformly good recovery after decompression. No reference was made to the need for grafting. In regard to iatrogenic injuries, the reported prevalence of injury to the ulnar nerve with the use of crossed K-wires has ranged from 2.5% to 6% Brown and Zinar, 8 in reviewing 162 fractures, identified four iatrogenic s of the ulnar nerve. All were explored and in all the medial wire was found to be injuring the nerve. They recommended urgent re-exploration in cases of post-operative nerve palsy. By contrast, Lyons et al 9 reported injuries to the ulnar nerve noted post-operatively after percutaneous cross K-wire fixation in 375 Gartland type-iii supracondylar fractures. Of these cases 17 were followed up and all did well irrespective of whether the wire was removed, the nerve explored or the patient treated conservatively. The authors comment that placement of the wire is only one of several factors implicated in the development of a post-operative nerve palsy. It is common practice now to ensure that the medial wire is placed through a mini-medial approach in an attempt to reduce the risk of nerve injury. Skaggs et al 19 reported no significant reduction in iatrogenic injuries to the ulnar nerve when such an approach was used. By contrast, Green et al 18 reported only one case of transient sensory symptoms in the ulnar nerve in a two-surgeon series of 65 patients treated using a mini-incision technique. In all the cases in our series the medial wire had been introduced through a mini-medial incision. Rasool 5 documented nerve injury occurring secondary to constriction by the cubital tunnel retinaculum. Cases 12 and 26 were examples of this phenomenon in which scar tissue in the cubital tunnel had caused a complete degenerative of the ulnar nerve, with a good to excellent outcome after. Skaggs et al 19 reported no iatrogenic injury to the ulnar nerve when only lateral wires were used, and confirmed that adequate fixation of unstable supracondylar fractures was achieved by such a technique. De las Heras et al 20 identified two s of the VOL. 87-B, No. 1, JANUARY 2006

5 94 M. RAMACHANDRAN, R. BIRCH, D. M. EASTWOOD Table V. Suggested indications for nerve exploration after trauma Nerve incurred during closed or open reduction and stabilisation of fracture, particularly in the presence of an inadequate/incomplete reduction when the nerve has not been visualised Neuropathic pain Complete with sympathetic paralysis A nerve which deepens progressively between 8 and 12 hours Coexisting ischaemia ulnar nerve in 77 patients using a lateral technique and emphasised the need for stability of the fracture, if necessary using a third wire, to reduce the risk of nerve injury. None of these studies reported the incidence of traumatic nerve injury documented at presentation. As pointed out by Lyons et al 9 the observation of nerve injury post-operatively does not imply that it occurred as a result of the intervention it is possible that it had simply not been recognised at the time of presentation. Similarly, the trauma associated with the reduction may injure the nerve irrespective of whether percutaneous wiring techniques are used. In our patients all the wires had been removed before referral to our unit and we are unable to comment on whether or not the nerve s were due to penetration by the wires or damage associated with their introduction. Only two wires in two patients had been removed early because of the presence of a nerve palsy. Cases of direct damage by K-wires may have been recognised and treated locally and if recovery of nerve function followed they would not have been referred to our unit. Of the ten patients who underwent exploration, one neuroma appeared to be related to the site of insertion of the wire but most nerve s were secondary to entrapment within fracture callus or scar tissue. A conduction block may progress to a degenerative if the compressive element of the original injury is not relieved. The presence of persistent neuropathic pain implies ongoing nerve compression and injury and should dictate further investigation and relief of compression. Clinical examination should also concentrate on sympathetic function. A warm dry digit implies that there is nerve dysfunction and indicates the need for exploration of the nerve. Our suggested indications for exploration are given in Table V. We conclude that contrary to the implications in the recent literature that nerve injuries associated with supracondylar fractures invariably recover spontaneously and well, certain nerve injuries with complete s on neurophysiological studies and those in whom the anticipated clinical recovery does not occur require assessment and management in a specialist unit. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. References 1. 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