Introduction
Intramedullary nailing is the standard or ideal treatment option for fracture shaft of long bones like femur and tibia. After fixation of fracture amount of gap present in between fracture ends determines the future of union. Large residual gap at fracture site can lead to delayed union or nonunion.1 Non union is the challenging problem to orthopedic surgeon as it requires multiple procedures thereby increasing treatment cost and patient morbidity. Various methods have been proposed to decrease fracture gap intraoperatively like avoiding too much traction, releasing traction before locking the nail, reverse hammering technique, forward striking technique etc.2 During nailing intraoperatiely, the AO trauma association recommends the reverse/backstroke technique immediately after distal interlocking. But on searching English literature, when and how to use or the therapeutic effect of the technique hardly been referred. Hence this study aims to asses the effectiveness of reverse hammering on fracture union in transverse fracture of long bone nailing as well as possible complications of this method
Materials and Methods
We studied Seventy six patients with transverse fracture of long bone (femur, tibia, & humerus) treated with close reduction and internal fixation with interlocking nailing were enrolled in a prospective study conducted at the department of orthopaedics, BMC Sagar from Dec. 2012 to March 2021 who fulfilled the inclusion criteria.
Inclusion criteria
Adults patients; (age>18yrs and less than 50yrs), Displaced fracture of a shaft of femur, tibia, or humerus, Fractures less than two weeks old.
Exclusion criteria
Patients unfit for anesthesia, skeletally immature patients, pathological fractures, compound fractures, polytrauma patients, patients with known alcohol or drug dependency, those who knew that they would be unable to participate, those participating in other clinical trials of a drug or device were also excluded, neuromuscular disorder & Inflammatory arthritis. The mean age of 40 male and 36 females was 36.86 years (Range 18 to 50years). The most common mechanism of injury was road traffic accident, then trauma by fall. Most of cases were operated within seven days of the injury. (range 0-10days).
Surgical procedure
After obtaining written consent, patients fulfilling the inclusion criteria were taken up for close reduction and internal fixation with intramedullary locking nail. All lower limb fracture patient were done under regional anaesthesia. Out of the 11 humerus fracture patients, 4 of them underwent general anesthesia and the rest 7 underwent ultrasound-guided brachial plexus block. Using standard technique for close reduction and interloking intraedullary nail was done after reaming the canal. Nail which was one size less than the biggest size reamer used to ream the canal was put intramedullary and placement was confirmed with intraoperative C Arm machine. During operation fracture gap was assessed and after locking distal screw reverse or back hammering was done till fracture gap was closed subjectively, then only both static as well as dynamic proximal locking was done. Bone-grafting not done. Post-operatively, Sitting up in the bed was encouraged once the blockade effects were over as well as advised to do active and passive finger/toe as well as nearby joint motion exercises. On the 2nd postoperative, 1st check dressing was done & a radiograph was taken. On the 5th postoperative day, the 2nd check dressing was done, and the patient was discharged from the hospital if everything is fine. After splint removal patients were started on nearby joint range of motion exercises active as well as in passive form. Heavy weight lifting or weight bearing was not allowed for 12 weeks after surgery. All patients were followed up on the 11th day postoperative for stitch removal, 1month, 3 months, 6 months, and at the end of 9month post-operatively. At the time of follow-up, anteroposterior and lateral view radiographs of affected bone was taken for assessment of reduction and bony union. Range of motion was evaluated at each visit as well as scoring was done to asses union as per Hammer criteria as shown in Table 1. 3
Table 1
Radiologial classification of fracture healing according to Hammer et al
Results
At the end of three month and nine month grade of union no of case wise was as shown in Table 2.
Table 2
Mean time to achieve bony union was 4.5 months
In our study seven out of seventy six patient at the end of three month were having radiological grade three or less union which at the end of nine month only two patient out of seventy six patient were having nonunion.
One patient from femur interlocking developed hypertrophic type nonunion at the end of nine months he was revised with exhanged nailing after nine month One patient of tibial interlock developed superficial skin infection on 5th postoperative day he was immediately taken to operation theatre and thorough wound wash was given after opening sutures which was controlled around 10th postoperative day, then secondary closure was done and rest of the period was unremarkable. One patient from humerus interlock developed iatrogenic fracture during reverse hammering which is gone into nonunion at the end of nine months. After study period is over she was revised with plating and bone grafting. So overall complication was reported in three patients. There were no supraspinatus tendon irritation or rupture, implant failure, or nerve palsy.
So at the end of nine month followup period two cases gone into nonunion out of seventy six patients
Discussion
For closed displaced fractures of long bones diaphysis preferred method of treatment is closed reduction and intramedullary nailing. 1, 2 After fixation of fracture amount of gap present in between fracture ends is the major factor in determination of union. 4, 5 Various methods have been proposed to decrease fracture gap intraoperatviely like avoiding too much traction, releasing traction before locking the nail, reverse hammering/backstroke technique, forward striking technique etc.2, 4 Drosos GI said that after fixation of fracture if gap is more than 3mm in tibial diaphysis then chanes of non union are there. 6 Ferrara F et al did a study over remaining fracture gap in humerus diaphysis fracture and observed less callus formation in distracted fracture ends. 7 We evaluated backward hammering technique to reduce the fracture gap and possible complications. It avoids the need of dynamization thus risk of second surgery around 8-12 weeks. In our study seven out of seventy six patient at the end of three month were having radiological grade three or less union which at the end of nine month only two patient out of seventy-six patient were having nonunion one may be because of complication of iatrogenic fracture during reverse hammering. As compared to Lim SJ forward striking technique where they achieved bony union in all twenty cases, with a mean time of 5.7 months which is quite higher than our study here we achieved in mean time of 4.5 months, there sample size is less as comapred to our study. 8 Probably because of after reducing the gap and fixing nail in static mode provides better fixation, rotational control over the fixed bone fracture as well as fracture surfaces are in contact with axial loading and get a better chance of union. Weakness of studies were involving three long bones in study rather than involving single long bone, reaming in all cases which may promote union as reaming has local bone graft effect as well as increase inner wall and nail contact area leads to increased mechanical stability.
Conclusion
Our results have been encouraging. The operation is technically demanding but provides an excellent method to achieve union in intramedullary nailing of long bones. Reduction is maintained in due course of time. Early return to functional activity can occur with vigorous physiotherapy. Based on our results, we opine that reverse hammering method to reduce long bone diaphyseal transverse type fracture gap should be considered for patients requiring a faster return to function after the injury with due care of iatrogenic fracture. However, role of reverse hammering in long oblique or spiral long bone diaphyseal fracture is inconclusive and needs further studies to prove or disprove its role.
