The etiology of short stature affects the clinical outcome of lower limb lengthening using external fixation

Abstract

Background and purposeDistraction osteogenesis (DO) has been used to gain height in short statured individuals. However, there have been no studies comparing the clinical outcome of limb lengthening based on the etiology of the short stature. We assessed whether different underlying diagnoses are associated with varied clinical outcomes in these patients.MethodsWe performed a systematic review of the literature pertaining to lower limb lengthening using external fixation for short stature. Clinical outcomes including amount of lengthening, healing index (HI), and complications based on the underlying diagnosis for the short stature were documented.Results18 clinical studies were included, with 547 patients who underwent 1,581 lower limb segment lengthening procedures. Mean follow-up was 4.3 years. The average age at lengthening was less for individuals with achondroplasia/hypochondroplasia (A/H) (14.5 years) than for those with Turner’s syndrome (TS) (18.2 years) or with constitutional short stature (CSS) (21.7 years). Mean height gained was greater in patients with A/H (9.5 cm) than in those with TS (7.7 cm) or CSS (6.1 cm) group. The HI was better in A/H (30.8 days/cm) and CSS (32 days/cm) than in TS (45.1 days/cm). The reported complication rate per segment was lower for A/H (0.68) and TS (0.71) than for CSS (1.06).InterpretationPatients with A/H tolerated larger amounts of lengthening with fewer complications than those with other diagnoses.

Achondroplasia: Development, pathogenesis, and therapy

“…Surgical limb lengthening classically uses the Ilizerov procedure in which cortical long bones are cut (osteotomy), external fixators are placed proximal and distal to the osteotomy and distraction is applied gradually over many months to extend bone length (Paley, 1988; Schiedel and Rodl, 2012). The average length gained is ~20.5 cm after multiple procedures (applied to the femurs and tibias) (Kim et al, 2014; Donaldson et al, 2015). This surgical treatment allows functional gains and quality of life improvements.…”

“…The primary therapies that are proposed to patients with Hch include treatment with recombinant human growth hormone (r-hGH) or surgical intervention (see surgical approaches section) (Tanaka et al, 2003;Kim et al, 2014;Burghardt et al, 2015;Massart et al, 2015). R-hGH is indicated for the treatment of DEVELOPMENTAL DYNAMICS ACHONDROPLASIA 299 short stature in children with other skeletal dysplasias, such as L eri-Weill dyschondrosteosis and idiopathic short stature, which are associated with mutations in the SHOX gene (Fukami et al, 2016).…”

Clinical Practice Guidelines for Achondroplasia*

“…By considering at what age the patient would be able to do this, this procedure is only recommended for patients older than 12 yr (35). In a meta-analysis of lower limb lengthening procedures for ACH and hypochondroplasia, the average age was 14.5 yr, the average body height gained was 9.5 cm, the healing index (number of days required to lengthen the bone by 1 cm) was 30.8 d/cm, and the complication rate for lower leg or thigh lengthening procedures was 0.68 (36). Reported sequelae include drop foot, residual peroneal nerve paralysis, and valgus deformities of the knee and ankle joints.…”

Final adult height in long-term growth hormone-treated achondroplasia patients

“…Classically, limb lengthening has been performed to ameliorate body disproportion [3]. While individual studies suggest that tibial lengthening (TL), femoral lengthening (FL), and combined TL and FL add 4.0-10.5, 3.0-13.0, and 9.0-24.0 cm, respectively, to bone length or standing height of patients with ACH [4][5][6][7], a recent systematic review shows that the overall height gain in ACH/hypochondroplasia patients is 6-12 cm [8]. In addition, short-term growth hormone (GH) treatment has also been shown to be effective for accelerating height velocity and improving height SD score in ACH patients [9][10][11][12].…”