Patients undergoing femoral lengthening by external fixation
tolerate treatment less well when compared to tibial lengthening.
Lengthening of the femur with an intramedullary device may have
advantages. We reviewed all cases of simple femoral lengthening performed
at our unit from 2009 to 2014. Cases of nonunions, concurrent deformities,
congenital limb deficiencies and lengthening with an unstable hip
were excluded, leaving 33 cases (in 22 patients; 11 patients had
bilateral procedures) for review. Healing index, implant tolerance
and complications were compared.Aims
Patients and Methods
Between October 2001 and September 2009 we lengthened 242 lower-limb segments in 180 patients using the Intramedullary Skeletal Kinetic Distractor (ISKD). Mechanical failure was defined either as breakage of the ISKD or failure of the internal mechanism to activate. Retrieved nails which failed mechanically were examined by the manufacturer for defects. In all, 15 ISKDs in 12 patients (13 limbs) failed mechanically representing an overall failure rate of 6.2%, with fracture of the device occurring in ten of the 15 failures. Two nails in one patient failed to lengthen and had to be replaced. The manufacturer detected an error in the assembly of the nail, which prompted a wide recall. One nail jammed after being forcefully inserted, and two nails failed to lengthen fully. Lengthening was achieved in all 12 patients, although three required a second operation to exchange a defective nail for a new, functioning device. The ISKD is a complex mechanical device which lengthens by the oscillation of two telescopic sections connected by a threaded rod. The junction between these sections is surrounded by a keyring collar. This keyring collar is the weakest part of the device.
