Abstract
External fixation is a commonly performed orthopedic surgical intervention . Across knee external fixation is carried out for various indications related to bones , joints and soft tissues . We report our observations on 41 across knee external fixators applied on 39 patients studied over a period of 4 years .
Introduction
A joint spanning external fixator plays an equally important role in management of acute trauma befitting a part of damage control orthopedics as well as for multiple non traumatic conditions involving the lower limb/s . Across knee external fixation is mostly done fixing the femur and the tibia , with or without limited internal fixation simultaneously .
Review
Francois Malgaigne ( 1840’s ) is credited for the earliest form of modern external fixator , a claw like device used for management of patellar fractures . Parkhill (1894 USA) , Lambotte ( a Belgian surgeon 1902) , and Hoffman ( 1938 Switzerland) are noteworthy in the ensuing evolution of external fixation systems . In 1950’s Ilizarov (USSR) and others were instrumental in the development of ring or circular external fixators which they successfully utilized for distraction osteoneogenesis and other indications . External fixators have been applied on tibia , femur and other bones as well as across joints like knee , ankle , wrist etc. [ 5, 12 , 8 ].
Materials & methods
In a study carried out between January 2012 and December 2015 , 39 patients with 41 across knee external fixators [ 2 patients with bilateral fixators ] were selected on fulfillment of inclusion and exclusion criteria cleared / approved by research , ethics and other related committees . Inclusion criterion was patients 18 years or older. Exclusion criteria : patients with neurological deficits , patients with implants in situ due to earlier surgery .
Observations
Initial enrolment included 45 patients with 47 across knee fixators over 4 years but 39 patients with 41 external fixations could be followed up until end of study : 6 patients were lost to follow up for various reasons . Age ranged from 18 to 65 years : 37 males , 02 females . Mean age was 37.36 years . Male female ratio 18.5 : 1 . Majority 10 patients were between 41 & 50 years [ 25.64% , 10 males ] , followed by 9 between 21 & 30 [ 23.08% , 8 males , 1 female ] together accounting for nearly half of all the patients. The other female was in her fourth decade.
In 39 patients the commonest mode of injury was road traffic accidents [ RTA n = 34 , 87.1%] , followed by industrial accidents [ n= 3 , 7.89% ]. 2 patients had flexion deformity of knee. RTA and industrial accidents caused 44 fractures : 20 femur fractures , 24 tibia fractures and 1 knee dislocation . 25 fractures [ 56.8% ] were open , 19 [ 43.2% ] closed . Of open fractures 21 [ 84% ] were Gustilo Anderson III B , followed by 8% III C and 4% III A & II [1] each . According to AO classification : of 20 femur fractures 1 – 32 , 19 – 33 : of 24 tibia fractures 16 – 41 & 8 - 42 .
Indications : 36 patients were managed with across knee external fixation for 44 fractures on 38 limbs . 1 patient needed it after reduction of dislocation of knee . In 2 patients it was indicated for flexion deformity of knee . Majority 24 of 37 [ 64.8%] patients had across knee fixation within 2 days . 2 patients with flexion deformity were taken up 1 day after admission .The rest were operated within 1 week or later. Mean time for external fixation following injury was 2.65 days . Out of 39 across knee fixators in males 18 were applied on left side , 21 on right . Both female patients had left side involvement . In 2 males bilateral lower limb fixators were applied.
1 ring and 40 tubular fixators were applied . 36 fixators were unilateral biplanar with Schanz pins inserted laterally on femur and anteriorly /anteromedially on tibia . 4 fixators were bilateral uniplanar spanning both knee and ankle joints with Denham pins through calcaneum . 163 Schanz screws were applied on 40 tubular fixators . 8 pins passed through open wounds . Majority 80% fixators [ 32/40 ] had 2 pins each in femur and tibia . 9 K wires were inserted in 1 Ilizarov fixator . None of the K wires was through wound . 8 out of 38 knees were stabilized initially with limited internal fixation with K wires and /or cannulated screws .
All patients were started on physiotherapy from first post op day , made to stand and ambulate within 1st week . Post fixator removal all were started on knee range of motion and muscle strengthening exercises .
Results & Analysis
39 adult patients underwent 41 across knee external fixation on 41 lower limbs for 44 fractures of femur and tibia , 1 dislocated knee , and knee flexion deformity – 2 . They were followed up for an average period of 43.8 weeks [ 0.84 year ] : range 13 – 104+ weeks .
All 44 fractures united , fracture union 100% . Average union time was 25.75 weeks . Mal union was recorded in 5 out of 36 [ 13.88% ] patients. Delayed union was seen in 5 out of 44 fractures [ 11.36% ] in 5 of 36 [ 13.88% ] patients .
Pin tract infection [ PTI ] was seen in 16 Schanz pins out of 163 , 7 passed through wounds . 9 screws had grade I infection , 6 – grade II : these could be controlled by better pin tract care and / or local curettage and oral antibiotics . 1 screw had grade III infection with purulent discharge in 9th week , fixator was removed . Pin wise PTI was 9.82% [16/163] observed in 11 fixators of 40 tubular fixators [ 27.5% fixator wise PTI ] in 11 of 38 patients [ 28.95% patient wise PTI ]. In 1 patient with 1 ring fixator with 9 K wires no infection was seen.
Compartment syndrome was observed in 2 out of 41 [ 4.88% ] limbs involved in 2 of 39 [5.13%] patients . Knee flexion contracture was observed in 2 out of 41 [ 4.88% ] limbs involved in 2 of 39 [ 5.13% ] patients . None had deep vein thrombosis , osteomyelitis , septic arthritis , haematoma formation around knee in any affected limb .
Mean ROM of knee following fixator removal was 74.76 +/-25.79 degree ranging from 05 to 130 degree.
Discussion
In the past decades starting with Marsh et al 1995 [ 6 ] to Ganjwala et al 2014 [ 2 ] , 10 studies reported on from 4 patients with 5 across knee fixators to 75 patients with 75 fixators [ 5 ] for different indications . Park et al 2011 [ 7 ] recorded mean age of 17.5 years , other studies mostly above 40 and 50 years , in comparison to our 37.36 yrs.. Majority studies report higher male to female ratios e.g. 1.17: 1 ,1.29: 1,3.7: 1 to 5: 1 [ 1 , 10 ] to the present 18.5 : 1 . Studies reported indications : tibial plateau fractures , distal femur fractures , arthrodesis , HTO non union , deformity correction [ 6 , 1 , 11 , 3 , 2 ] . Some studies reported greater number of closed fractures [ 10 , 5 , 9 ] others open fractures [ 4 ] in comparison to the present 56.8% open and 43.2% closed fractures . 84% open fractures were grade IIIB , 8% grade IIIC . Duration of fixators reported in different studies range from 5.5 weeks to 26 weeks in comparison to the present study’s 10 weeks on an average , range 8 to 27.5 weeks [ 1 , 7 ]. Range of fracture union time in studies varies from 3 to 5.8 months [ 9 , 1 ] . In the present study average union time was 5.92 months .
Pin tract infections have ranged from 6.25% to 100 % of patients in studies [ 4 , 7 ] while in the present series PTI was 9.82% pin wise , 27.5% fixator wise and 28.95% patient wise . Incidence of mal union was 11.36% in comparison to 14% to 20% in other studies [ 6 , 9 ] . There was no nonunion but 11.36% [ n =5 ] delayed union was observed which was one of the contributory factors in the higher average of fracture union time .
Knee ROM reported in different studies averaged from 85 degrees to 126.9 . By the time of last follow up the present study witnessed an average range of movement of 74.76 . It is noteworthy that 57% fractures were open , 92% of them grade III B & III C with soft as well as hard tissue loss/es in a number of victims . ROM was noted to be less with increasing grade of compound fractures , the longer period of delay in external fixation , and the longer the fixator remained on the limb/s across the joint/s .
Conclusion
Based on correlation analysis knee ROM was found to be inversely related to severity of open fractures , time of fixator application since injury , and duration of fixator prior to removal.
Bibliography
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Source(s) of Funding
Self funded . No external assistance .
Competing Interests
None .