Transphyseal screws correct coronal deformities faster than growth modulation plates in distal femoral guided growth

Transphyseal screws correct coronal deformities more quickly than growth modulation plates in distal femoral guided growth: study

Hemiepiphysiodesis (guided-growth) procedures have become the primary method of treatment for coronal-plane knee deformities in skeletally immature patients. Two leading techniques involve the use of a transphyseal screw or a growth modulation plate. However, clinical references for the estimation of correction are lacking, and no consensus has been reached regarding the superiority of one technique over the other.

James McGinley et al conducted a study to compare the rates of correction for distal femoral transphyseal screws and growth modulation plates in age and sex-matched cohorts with coronal deformities.

The data of 62 knees treated at Scottish Rite for Children, Frisco, Texas (tertiary pediatric orthopaedic hospital) were retrospectively reviewed. Thirty-one knees were included in each matched cohort. In the plate group, 8 patients had bilateral involvement and 15 patients, unilateral. In the screw group, 12 patients had bilateral involvement, and 7 patients, unilateral. Each case was measured for limb length, mechanical axis deviation (MAD), mechanical lateral distal femoral angle (LDFA), and bone age. Bone age was calculated according to the method of O’Connor et al., a system of anteroposterior epiphyseal knee evaluation based on the findings and atlas by McKern and Stewart.

Key findings of the study:

• The average age (and standard deviation) at the time of the procedure was 12.9 ± 1.1 years.

• Both the MAD and LDFA rate of correction significantly differed between the screw and plate cohorts.

• The MAD rate of correction was observed to be 0.42 ± 0.37 mm/week (1.69 mm/month) in the plate cohort and 0.66 ± 0.51 mm/week (2.64 mm/month) in the screw cohort.

• The LDFA rate of correction was observed to be 0.120 ± 0.130/week (0.500/month) in the plate cohort and 0.190 ± 0.190/week (0.770/month) in the screw cohort.

The authors concluded that – “the current study is the first, to our knowledge, to retrospectively compare age- and sex-matched cohorts of coronal knee growth modulation utilizing transphyseal screws and growth modulation plates. This study generated proposed simple clinical references of the estimation of the rate of correction of the LDFA and MAD for both hemiepiphysiodesis methods. The results also suggest that transphyseal screws may affect optimal correction measured by MAD and the LDFA more quickly than growth modulation plates for distal femoral guided growth in coronal knee deformities during the initial months of treatment.”

Level of Evidence: Therapeutic Level III. 

Further reading:

Faster Rate of Correction with Distal Femoral Transphyseal Screws Versus Plates in Hemiepiphysiodesis for Coronal-Plane Knee Deformity

Age- and Sex-Matched Cohorts of Skeletally Immature Patients

James McGinley, Hannah Worrall et al

J Bone Joint Surg Am. 2023;105:1252-60

http://dx.doi.org/10.2106/JBJS.22.01122