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Fifteen patients with 17 post-burn bony ankylosed elbows (two bilateral) fixed at a mean of 72.5°±27.5° flexion were treated with Baksi sloppy hinge elbow arthroplasty. All patients agreed to avoid strenuous use of their replaced elbows. There were four males and 11 females whose ages varied from 21 to 48 years (average 31.6 years). One of the five patients who had severe anterior skin contracture required release. One patient died during the early follow-up period. During the follow-up studies which ranged from 11 to 23 years (average 14.1), eleven patients (68.7%) regained painless stable motion with mean recovery of arc of flexion from 20°±10° to 107.5°±17.5° with mean range of flexion 90°±20°. Good forearm motion was retained in all cases. According to the assessment score (Morrey BF, The elbow and it’s disorder, 2nd edn. W.B. Saunders, Philadelphia, 1993), nine (56.2%) patients were recorded as excellent, two (12.5%) as good, and five (31.5%) as poor who were considered as failures. The five failures required removal of the prosthesis but retained acceptable elbow function due to periprosthetic fibrosis connecting the adjacent bone ends.
15 patients présentant 17 séquelles de brûlure avec raideur du coude en flexion, dont 8 ankylosés (deux bilatéraux) et fixés, avec une moyenne angulaire de 72.5°±27.5° ont été traités par une prothèse du coude de type Baksi. Cette série était composée de 4 hommes et 11 femmes dont l'âge variait de 21 à 48 ans (moyenne 31,6). Un patient qui présentait une ankylose antérieure extrêmement fixée avec une rétraction cutanée antérieure sévère a nécessité une libération. Un patient est décédé durant la période de suivi. La surveillance s'est effectuée sur une période de 11 à 23 ans (moyenne 14,1). L'ensemble des 11 patients, 68,7%, ont recouvré un coude stable, mobile et non douloureux avec une mobilité, pour huit d'entre-eux pouvant aller jusqu'à 107° de flexion. La mobilité de l'avant bras était satisfaisante dans tous les cas. L'évaluation montre que neuf patients ont eu un excellent résultat (56,2%), deux un bon résultat (12,5%), et cinq un résultat médiocre (31,5%) considérés comme un échec. Ces derniers ont nécessité l'ablation de la prothèse et ont gardé des fonctions acceptables du coude secondaires à une fibrose périprothétique.
Bony ankylosis of the joints entails a severe degree of handicap which may occur following 20% (or more) body surface area of deep burns , and the elbow is the most common joint involved [5, 10]. Though rare, this affliction is still encountered in developing parts of the world. Post-burn ankylosis usually results from heterotopic bone formation [5, 10, 11, 15], whose exact aetiopathology remains unclear [5, 6, 10, 15]. The heterotopic bone is commonly seen to be extraarticular or periarticular as reported by several authors [4, 5, 10, 11, 15] and produces severe functional limitation. While intraarticular ankylosis by septic destruction is rarely reported [5, 11, 16], only extraarticular heterotopic ossification may be managed by excision of extraosseous bone . For intra or periarticular or combined intra and peri- or extraarticular ankylosis, nonprosthetic arthroplasties like excision or anatomical arthroplasty are not consistently successful . In such types of post-burn ankylosis of the elbow, where the aetiopathology remains unclear [5, 10, 15], the outcome of total elbow replacement (TER) is of interest though not yet reported in the literature.
Fifteen patients with bony ankylosis in 17 elbows (Figs. 1 and and2)2) fixed at a mean of 72.5°±27.5° flexion following healed deep burns of 18–54% body surface area were selected for our study (Table 1). The granulating wounds after the burns persisted for three to seven months (average 4.5). Elbow ankylosis had been present for an average 3.02 years (range, 2–8). Two patients had bilateral ankylosis. The cases having extraarticular heterotrophic ossification associated with preserved joint spaces were excluded from this study. There were also longitudinal skin contractures in front of the elbow in five cases, which might have been an additional cause of limitation to elbow extension. The nature of the joint ankylosis was evaluated clinically, radiologically, and during exploration of the joint as well as by histopathological studies across the excised ankylosed joint. Forearm motion remained unaffected in all cases.
There were four males and 11 females. Their ages varied from 21 to 48 years (average 31.6). Only those young patients who agreed to avoid strenuous use of their elbows including lifting of heavy weights were selected for replacement arthroplasty. Baksi sloppy hinge prostheses [1–3] were used to replace the post-burn ankylosed joints during the period from 1984 to 1996. This sloppy hinge design [1, 3] (Fig. 3) is fabricated from metal with 7°–10° varus valgus laxity at the hinge section due to a potential gap between the motion bearing surfaces, which leads to minimum contact areas at the articulation, and hence minimal metal dust liberation. Owing to the presence of laxity at the hinge section, any strain occurring across the prosthetic joint will dissipate primarily to the surrounding soft tissues, so that less strain will occur at the bone–cement interface .
The surgical technique described by Baksi  was followed in this study. Through a posteromedial incision to the elbow, the ulnar nerve was isolated and transposed anteriorly and the flexor carpi ulnaris was elevated from the medial border of the ulna. In six cases the ulnar nerve was encased within the heterotopic bony mass which was removed cautiously to deliver the ulnar nerve. By subfascial dissection medially and laterally, the triceps was exposed and separated from the posterior surface of the humerus and ankylosed joint. Elbow flexors were separated from the anterior surface of the lower part of the humerus. The extraosseous bony mass was seen predominately on the posteromedial aspect of the elbow joint in seven cases and posteriorly extended proximal to the olecranon process in two cases. The radial head was excised first. The humerus was sectioned transversely just above the olecranon fossa and a proximal L-shaped ulnar cut was made keeping the insertion of triceps and brachialis muscles intact to expose the medullary canals. The ankylosed bony mass was isolated and a longitudinal sagittal cut section was made for observation and histological studies across the joint level (Fig. 2 inset). After excision of the ankylosed elbow mass the resultant gap was compared to the height of the hinge section of the elbow prosthesis to accommodate it during full flexion and extension of elbow. If that gap was inadequate due to long standing contracture of flexors or extensors, further bone was excised transversely from the lower cut end of humerus. The appropriate size of the prosthesis was then selected for insertion. The prosthetic stems were then cemented inside the medullary canal of the corresponding humerus and ulna. The hinge components were assembled together and secured by a locking screw.
Wounds were closed in layers with application of a drain around the prosthesis. Postoperatively, the elbow was immobilised in a plaster cast in almost full extension.
Severe degrees of contracture of skin and subcutaneous tissues in front of the elbow, causing limitation of extension of the replaced elbow, needed release in case 15, eight weeks after the prosthetic replacement to improve extension of the elbow.
The suction drain was removed 48–72 hours after the operation. On the seventh postoperative day, dressings were changed and the elbow was kept in an adjustable elbow splint where the elbow was immobilised in the position of maximum flexion and extension alternately for six hours. If the wound was found to be healthy without oedema at that time, passive elbow movements were started. Otherwise, it was delayed until removal of stiches on the 14th postoperative day. Active flexion and extension of elbow was possible after recovery of muscle power about four to five weeks after the operation when the elbow splint was discarded. Heavy weight lifting and strenuous use of replaced elbows are discouraged permanently.
Fourteen patients with 16 elbow replacements were evaluated during the follow-up period which was an average of 14.1 (range, 11 to 23) years (Table 1). Case 2 died four years after surgery following chronic nephritis and was excluded from evaluation of the results. The patients were assessed according to Mayo elbow performance score , comprising of pain around the elbow during movement, range of elbow and forearm motion, dynamic stability of elbow, and functional activities of replaced elbow. Overall, 11(68.7%) elbows regained painless stable motion. Preoperatively, all elbows were fixed at a mean of 72.5°±27.5° flexion. Following the operation, mean recovery of arc of flexion ranged from 20°±10° to 107.5°±17.5° with mean range of motion at 90°±20° (Table 2). Good forearm motions was retained in all cases. Among 16 elbows, nine (56.2%) had excellent (Figs. 1, ,2,2, ,33 and and4),4), two (12.5%) good, and five (31.25%) had poor results. Poor cases were considered failure and were due to uncontrolled infection in case 10, nonrecovery of active contraction of muscles around both the elbows in case 13, and 4 mm aseptic loosening around both humeral stems in case 4 (Fig. 5a). Hence, the failure rate in our series of post-burn ankylosis was 31.2%.
Furthermore, radiological evaluation was made according to the classification of Morrey et al.  as follows:
Radiolucent lines at the bone–cement interface appeared during the period of 6.5–8.8 (average 7.2) years follow-up. Radiolucent lines up to 2 mm at the bone–cement interface (type 2) developed in nine (56.2%) elbows around the humeral stems in all patients, around the ulnar stem in one patient, and 2–3 mm radiolucent lines (type 3) in two (12.5%) elbows around the humeral stem in patients who had stable elbow motion. Case 4 developed 4 mm aseptic loosening (type 4) around the humeral stem (Fig. 5a) resulting in painful unstable elbow motions which required removal of the prosthesis. Case 2 died four years after the operation from chronic nephritis without showing any radiolucency of any component. Case 10 underwent removal of prosthesis following delayed deep uncontrolled infection 13 months after the operation with patchy infective radiological loosening resulting in painful elbow motion especially during strenuous activity.
There was superficial infection of wound margin in three cases managed satisfactorily by conservative treatment. Two cases developed deep infection of which one was controlled and one remained uncontrolled even after repeated irrigation and debridement and ultimately needed removal of prosthesis. Two patients developed postoperative ulnar neuropraxia and recovered spontaneously.
Fifteen patients with 17 elbows having a combined peri and intraarticular osseous bridge were treated by prosthetic replacement. Four of them also had extraarticular ankylosis. As the majority of the affected patients were young females, their functional disability was a matter of great concern. We selected only those patients whose burns had been healed for at least two years before their prosthetic replacement was considered due to the fear of flaring up of any dormant skin infection. The postburn skin contractures, wherever present in our series, were on the anterior aspect, whereas the exraarticular heterotopic bony mass seen radiologically was at a distance, suggesting the ankylosis was not a result of thermal insult. Furthermore, the histopathological study of tissues taken across the excised elbow joint mass showed presence of bony bridges across the joint in places and evidence of degeneration of articular cartilage in other areas with subarticular patchy calcification appearing to be the precursor of new bone formation. The radiohumeral joint was not involved in any case, resulting in the retention of good forearm motions in all.
Excision of the ankylosed bony mass followed by replacement arthroplasty using Baksi’s sloppy hinge prosthesis provided recovery of satisfactory elbow motion in the majority (68.7%) of patients. Baksi’s prosthesis, though all metal, is biomechanically acceptable because of it’s inherent laxity and minimum contact areas during elbow movement and, moreover, the elbow joint is not a weight bearing joint except during flexion against gravity and weight lifting .
It is important to note that there was no recurrence of heterotrophic new bone formation around the prosthesis postoperatively. In the absence of such new bone formation, nonrecovery of muscle function and motion in both elbows in case 13, who had a history of chronic granulating wounds persisting for seven months, may be due to myofibrosis as postulated by Evans . Hence, electromyographic evaluation around the elbow is mandatory before considering its prosthetic replacement in post-burn ankylosis.
Only two cases in our series (cases 2 and 10), with delayed healing of granulating wounds lasting more than three months and shorter time span between the healing of the wounds and elbow replacement (about two years), developed delayed deep infection, which may be due to flaring up of dormant skin infection following deep burns. On the other hand, the cases in which granulating wounds healed up in less than three months and the time span between the healing of burns wounds and replacement was more than three years, such complications were not encountered. Higher incidence of failure of elbow replacement in post-burn ankylosis was 31.2% in our series compared to replacement for post-traumatic ankylosis (18%)  and rheumatoid arthritis (9%) . The higher failure rate may be due to longer follow-up period having a greater chance of morbidity in our post-burns series compared to other groups and the cases with uncontrolled infection needing removal of prosthesis.
Radiolucent lines up to 2 mm at the bone–cement interface appeared commonly around the humeral stem, rarely around the ulnar stem were often asymptomatic and did not hamper the functional outcome, and hence provided good results. The cases where prostheses needed removal either due to 4 mm loosening (Fig. 5a) in case 4 (Table 1) or due to delayed infection in case 10 (Table 1) were immobilised in a plaster cast in maximum flexion for seven weeks followed by gradual mobilisation and physiotherapy; they retained relatively stable elbow motion due to fibrous tissues connecting the adjacent bone ends along with reorientation of muscle balance. The bone ends remained stable for more than 11 years after removal of the prosthesis with adequate function , and little deterioration was noticed in comparison to that reported after fascia lata or other interpositional arthroplasties [8, 9]. Similar stable elbow movements were noted after removal of prosthesis at six-year follow-up (Fig. 5b) in case 4 and 17-year follow-up in case 10 (Table 1). These observations encouraged our ideas for the prosthetic replacement of elbows even in young individuals who agreed to avoid heavy weight lifting and strenuous use of replaced elbows.
D. P. Baksi, Phone: +91-33-23372316, Email: moc.liamtoh@htroiskabpd.
A. K. Pal, Email: moc.oohay@lapkaohtro.
N. D. Chatterjee, Email: moc.liamg@htroeejrettahcdn.
Debadyuti Baksi, Email: moc.liamg@htroiskabdd.