The intramedullary skeletal kinetic distractor (ISKD): first clinical results of a new intramedullary nail for lengthening of the femur and tibia

Abstract

In 1986, a programme was initiated by the senior author to develop a reliable, mechanically activated, intramedullary lengthening device with a non-invasive means of measuring the progress of lengthening without X-ray. We report results of design, biomechanical testing, in vivo animal testing and clinical implantation of the first 20 intramedullary skeletal kinetic distractors (ISKDs) in adult patients with limb-length discrepancies.Twenty ISKD devices were implanted in 18 patients (14 males and four females). Lengthening was required due to infection (ten), trauma (six), polio (one) and burn (one). Six femurs and 14 tibias were lengthened. Mean patient age was 40 years (range, 18-65 years).No implant related infections, non-unions, malunions or joint contractures were observed. A design change was made following two initial hardware failures, after which there were no further breakages. Average lengthening was 49 mm (range, 29-110 mm). The average lengthening rate was 0.82 mm/day (range, 1.7-0.4 mm/day). Ability to work, walk and drive before, during and after treatment with the ISKD compared favourably with that of similar patients undergoing lengthening using the 'monorail' method in our practice.The ISKD appears to be a safe and cost-effective alternative to external fixators that reduces lifestyle disruption and complications during adult limb-lengthening procedures.

Internal Lengthening Device for Congenital Femoral Deficiency and Fibular Hemimelia

“…The other method that has been previously used is the ISKD, which is the only intramedullary device for lengthening that has been in general use in United States. This method is associated with several complications, such as premature or delayed consolidation with difficulties in controlling the distraction rate rhythm, implant breakage, and mechanical failure [9,20,22,35,36]. Mahboubian et al [22] reported complications requiring additional surgeries such as exchange nailing or removal of the ISKD in six of 12 patients.…”

“…For the past 10 years, the only FDA-approved intramedullary lengthening device has been the Intramedullary Skeletal Kinetic Distractor (ISKD) (Orthofix Inc, Lewisville, TX, USA). However, intramedullary lengthening is associated with complications, including premature or delayed consolidation with difficulty in controlling the rate of distraction, implant breakage, and mechanical failure [9,16,[20][21][22]35].…”

Current concepts of leg lengthening

“…2 cm to max. 17.4 cm) for Ilizarov ring fixators (IRF) [48,57,58] and intramedullary nails [16,46,50,[59][60][61][62][63][64] and around 2.5-3 cm (min. 8 mm to max.…”

“…The intramedullary skeletal kinetic distractor (ISKD, Orthofix Inc., McKinney, TX, USA) [62] comes as straight humeral, femoral and curved tibial titanium alloy nail of 10.5-14.5 mm in diameter and 50-80 mm of distraction. It bears significantly less complications than the Albizzia nail.…”

Is Botulinum Toxin Type A a Valuable Adjunct During Femoral Lengthening? A Randomized Trial

“…Distraction osteogenesis using these devices maintains good adjacent joint motion compared with lengthening using external fixators. However, several studies have reported an observed loss of knee ROM despite lengthening using an internal lengthening device [4,15,16]. Given other applications for BtX-A, we rationalized that BtX-A injections were an appropriate treatment to investigate in our study, because muscle structure is well preserved during the use of internal lengthening devices.…”