O0815 Oct.3: 3:57pm - Comparative Study of Percutaneous Trans-Epiphyseal Screws (PETS) Versus Tension-Band Plating (TBP): Clinical and Radiological Outcomes for Correcting Limb Length Discrepancy (LLD).

Background/Purpose: The purpose of this study was to compare the efficacy and outcomes between tension-band plating (TBP) and percutaneous epiphysiodesis using transphyseal screws (PETS) for correction of LLD.

Methods: Retrospective review of children who underwent epiphysiodesis with either TBP or PETS of the lower extremity from June 2008 to December 2018. LLD and complications were reviewed at completion of treatment, defined as removal of hardware or physis closure, and most recent follow-up. Continuous variables were compared using t-test or Wilcoxon rank-sum test. Fisher’s exact test or χ2 test were used to assess categorical variables.

Results: 47 growth modulation surgeries with either TBP (24 femur or tibia/17 limbs) or PETS (23 femur or tibia/15 limbs) were performed. TBPs were performed at a younger age compared to PETS (11 vs 13.1years, P<0.005). Length of epiphysiodesis treatment was similar between groups (TBP 23.5 vs PETS 24months, P=0.132), however follow-up was shorter in the PETS group (TBP 5.4 vs PETS 2.5years, P=0.001). Operative time (P=0.047), length of hospital-stay (P=0.014) and time to return to full activities (P=0.043) were significantly shorter in PETS.
In this cohort, pre-operative LLD was 2.7±1.6cm and predicted LLD at maturity 3.2±1.7cm. Table 1 shows comparison of LLD measurements between surgical groups. In the TBP group LLD corrected from 2.64 to 1.38cm at most recent follow-up (P=0.005) and in the PETS group from 2.76 to 1.08cm (P<0.001), achieving on average a correction of 1.42cm in the TBP and 1.68cm in the PETS group (P=0.666). The rate of LLD correction during treatment was 0.49 ±0.9 cm/year for limbs treated with TBP and 1.0 ±1.1 cm/year for limbs treated with PETS (p=0.185). 8 TBP cases (47%) and 9 PETS cases (60%) had achieved LLD ≤2cm at completion of treatment (P=0.502), and at most recent follow-up this increased to 11 (65%) in the TBP and 12 (80%) in the PETS group. No differences existed in total number of complications or angular deformity between groups (P>0.05 for each comparison). Revision surgery due to persistent LLD or angular deformity occurred in 11 limbs treated with TBP and 3 limbs treated with PETS (P=0.016; a list of complications and revisions is provided in Table 2). Logistic regression adjusted for age at surgery did not reveal that TBP was significantly associated with complication (OR=2.89, 95%CI 0.49-17.03; P=0.242) and revision surgery (OR=3.98, 95%CI 0.63-26.20; P=0.142).

Conclusion: This study showed that PETS and TBP are reliable options to achieve limb length equalization. PETS was associated with shorter operative time, shorter length of hospital-stay and faster return to pre-operative function.