Essay Example on Comminuted fragments due to complexity of distal humeral Anatomy

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Apart from difficulty in aligning the comminuted fragments due to complexity of distal humeral anatomy limited subchondral bone stock and small fragments to realign there are few other challenges like restricted space for instrumentation at the distal segment the proximity of the nerve and the need to maintain repair integrity under a large range of motion and low to moderate loading 4 Open reduction and internal fixation using double plating system is considered as the gold standard method of fixation of intra articular distal humerus fracture 3 5 There always been a controversy regarding the plate configuration which is strong enough to provide rigid fixation 



However the two most commonly used plate configuration are parallel and orthogonal plating the superiority of one plate over another in a clinical setting is still not established Principle behind parallel configuration is that greater number of screws are allowed to be inserted across the trochlea and capitellum from both lateral and medial sides of the humerus that provides stable screws interdigitation and forming a complete arch construct aligned with the plane of elbow motion 9 Whereas in orthogonal configuration create a strong girder like arrangement which allows early active mobilization of elbow 10 Many biomechanical studies have been done in the laboratory to illustrate the rigidity of dual plate configuration but its validity in vivo is largely unknown because most of them have been done either on bone models11 15 or fracture pattern is not simulating the clinical scenarios 11 13 16 19 In an epidemiological study of Robinson CM et al the incidence of extra articular fracture with supracondylar comminuted gap was only 7 2 among distal humerus fracture rest fracture line extending to intercondylar area 1 Hence the models replicating supracondylar gap model11 16 19 does not simulate the clinical scenario If we take all above parameters supracondylar gap and synthetic models into consideration there are very few biomechanical studies relevant to actual clinical situation of intercondylar fracture with supracondylar comminution gap 20 



22 The studies done biomechanically described above not only used different fracture models but the techniques they used for mechanical testing for the fixation construct also varied In some studies applied static loading in the axial AP and torsional planes whereas others additionally tested cyclical loading and loading to the point of failure of the implant construct Two biomechanical laboratory studies are the most well designed comparative study 20 21 Both Got et al and Stoffel et al used most challenging fracture model that included a segmental intercondylar split in osteoporotic or osteopenic cadaveric humerus simulating an elderly female patients with a comminuted intra articular fracture Although the construct used in both studies were almost similar but observation was different Stoffel et al observed that under physiological load the parallel system provide significantly higher stability in terms of stiffness and resistance to plastic deformation under axial loading and higher stiffness under torsion On the other hand Got et al observation was under cyclical AP loading of intra articular fragments orthogonal plating was found stiffer in torque to failure and both construct were similar in all other parameters As far as clinical outcome comparison is concerned there are three prospective studies in the literature 2 6 7 In the study Shin SJ et al 6 perpendicular plating using reconstruction plates were compared with the parallel plating using precontoured anatomical plates So it is very difficult to validate the result because now precontoured anatomical plates are being used in most of the centres because it allows more screws insertion in multiple directions to achieve firm fixation and also save precious time of surgery as plates are pre bent

6 However precontoured anatomical plates were used in rest of two studies which we think more relevant in current prospect In present study the mean time taken to perform the procedure was significantly more in parallel plating group Whereas the difference in operation time in other studies3 4 were not significant probably because of method of olecranon osteotomy fixation In present study parallel plating group osteotomy was fixed using tension band wiring but in perpendicular plating group most of them were fixed by 7 mm cancellous screw which took lesser time to accomplish Likewise the blood loss in parallel plate was more than the perpendicular plating group because of more duration of surgery and more soft tissue stripping that is done in parallel plating So it can be inferred from above observation is that osteotomy fixation with cancellous screw can decrease the duration of surgery and hence blood loss also Biomechanically parallel plate construct have been found to be more stiff and rigid than perpendicular plate construct But the findings of laboratory condition does not seem to be deciphered in actual clinical setting because the mean time of fracture union was seen in slightly early in parallel construct but that difference was not significant The mean union time was 3 months in group parallel and 3 5 months in group B Our finding was similar to the finding of other study in term that early union was achieved in parallel plate construct The arc of motion MEPS and DASH score in our study were slightly better than previously published literature 2 6 7 This has been summarized in the table no 3 The probable cause of this difference is postoperative supervised physiotherapy and less number of complications affecting the score As far as comparison in between the group is concerned there were no significant difference were observed at the end of final follow up


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