Percutaneous epiphysiodesis using transphyseal screws for limb-length discrepancies: high variability among growth predictor models

Staples, tension-band plates, and percutaneous epiphysiodesis screws used for leg-length discrepancy treatment: a systematic review and proportional meta-analysis

BACKGROUND AND PURPOSE

The primary aim of this systematic review and meta-analysis was to evaluate the success rate of 3 different epiphysiodesis techniques with implant usage for the treatment of leg-length discrepancy (LLD) in the pediatric population. The secondary aim was to address effectiveness (final LLD) and the reported complications of staples, tension-band plates (TBP), and percutaneous epiphysiodesis screws (PETS).

METHODS

In this systematic review we searched MEDLINE (PubMed), Embase, Cochrane Library, Web of Science and Scopus for studies on skeletally immature patients with LLD treated with epiphysiodesis with an implant. The extracted outcome categories were effectiveness of epiphysiodesis (LLD measurements pre-/postoperatively, successful/unsuccessful) and complications that were graded on severity.

RESULTS

44 studies (2,184 patients) were included. 455 underwent epiphysiodesis with PETS, 578 patients with TBP, and 1,048 with staples. Successful epiphysiodesis was reported in 76% (95% confidence interval [CI] 61-89) with PETS (9 studies), 67% (CI 54-79) with TBP (10 studies), and 51% (CI 28-65) with Blount staples (8 studies). From pooled analysis, the severe complications rate was 7% for PETS, 17% for TBP, and 16% for Blount staples. Angular deformity was reported in 4% after PETS, 10% after TBP, and 17% after Blount staples.

CONCLUSION

Our results showed that epiphysiodesis with PETS implants was the most successful technique. PETS had a higher success rate, fewer severe complications, and a lower proportion with angular deformity.

Epiphyseal-entry cannulated screws for temporary guided growth of the knees: a retrospective review of 89 cases

Guided growth affects the physis in children to produce a desired effect. Several devices achieve alteration of growth, including staples, plates, and screws. Complications can include device failures, failure to modulate growth as expected, and unintended physeal arrest. We present the results of a unique technique designed to minimize these complications. This was a retrospective review of guided growth at the knee at a single institution utilizing cannulated screws with epiphyseal-entry points. Each case was reviewed to determine the presence of complications related to guided growth, including implant breakage, implant pull-out or pull-through, iatrogenic physeal arrest, failure to modulate growth, and the incidence of revision surgeries. There were 89 patients who had 146 epiphyseal-entry guided growth procedures with a total of 221 4.5 mm cannulated screws. There were no iatrogenic physeal arrests. Five (2.26%) screws in 4 (4.49%) patients had either a broken screw or screw pull-out/pull-through requiring revision procedures. Three patients had osteotomies after skeletal maturity. Four had revision-guided growth for other reasons: 2 due to a lack of timely follow-up, 1 for iatrogenic genu varum without implant failure, and 1 due to recurrent deformity after implant removal. Revision procedures were unanticipated in 6 (6.74%) patients. This study describes a technique for placing cannulated screws at the knee with epiphyseal starting points. Our rate of complications and number of revision surgeries compare favorably with those noted for other techniques. Guided growth using epiphyseal-entry cannulated screws is a safe, effective option for most patients.

Does Combining Drilling and Curettage to Percutaneous Trans-epiphyseal Screws Improve Correction of Limb Length Discrepancy? A Comparative Study

Objectives

Physeal drilling and curettage (PDC) and percutaneous epiphysiodesis using transphyseal screws (PETS) are among the most widely used techniques to treat leg-length discrepancy (LLD). This study compared the efficacy and outcomes between PETS alone and PETS combined with PDC (PETS + PDC).

Methods

Retrospective study of children who underwent epiphysiodesis of the proximal tibia or distal femur with either PETS or PETS + PDC between 2008 and 2018 at a single institution. Radiographic parameters and complications were reviewed at completion of treatment and most recent follow-up.

Results

A total of 23 epiphysiodeses in 15 patients, average age 13.1 years, with either PETS (13 femur/tibias) or PETS + PDC (10 femur/tibias) were included. PETS patients were treated for a longer time (median: 24 months vs 11 months, p = 0.004), however, follow-up time was similar between groups (p = 0.577), on average 2.7 years. In the PETS group, LLD decreased from 2.55 to 0.84 cm at most recent follow-up (p = 0.010), and in the PETS + PDC group from 3.01 to 1.2 cm (p = 0.005), achieving a correction of 1.71 cm for PETS and 1.83 cm for PETS + PDC (p = 0.871). A correction of LLD to ≤ 2 cm was achieved in 8 PETS (89%) and 4 PETS + PDC cases (67%) (p = 0.525). Two PETS patients (22%) and 1 PETS + PDC (17%) patient returned to the OR for further correction due to persistent LLD (p = 1.000). No differences existed in total number of complications, angular deformity or return to physical activity between groups (p ≥ 0.05 for each comparison).

Conclusions

This study showed equal efficiency in resolving LLD between the PETS and PETS + PDC procedures with minimal operative complications.Level of Evidence III.

A Method of Time Prediction in Epiphysiodesis for Limb Length Discrepancy Based On Multiplier

Objectives

The most critical step in the calculation of final limb length discrepancy (LLD) is estimating the length of the short limb after skeletal maturity(Sm). Paley's multiplier method is a fast, convenient method for calculating Sm and LLD after skeletal maturity; nonetheless, the calculation of the process of Sm and LLD in acquired type cases is complex in contrast to congenital type in this method. Notwithstanding, the multiplier method uses a variable called "growth inhibition" for the calculation process in acquired type LLD; however, its mathematical proof has not been published yet. The present study aims to find out whether there is an alternative way to estimate the length of Sm and LLD in skeletal maturity without using growth inhibition (GI) and its complex calculation process in acquired type LLD.

Methods

We used trigonometric equations to prove the GI concept and conducted proportionality analysis to calculate the length of short limbs and LLD in skeletal maturity without using GI.

Results

Based on the results, the following proportionality can estimate the length of the short limb in skeletal maturity. (ΔLm/ΔL = ΔSm/ΔS).

Conclusion

The GI concept can be proved trigonometrically; nonetheless, its numerical value is not necessary for estimating the length of the short limb in skeletal maturity. Instead, a simple proportionality analysis serves the purpose of calculation.

The efficacy of two-hole tension band plates in the treatment of lower extremity limb length discrepancy

The main purpose of our study was to investigate the efficacy of dual two-hole tension band plates in the treatment of lower extremity limb length discrepancy (LLD). We retrospectively reviewed patients who underwent epiphysiodesis utilizing dual two-hole tension band plates due to lower extremity LLD between January 2012 and June 2018. The efficacy of epiphysiodesis was defined as the inhibited percentage of the expected growth of the physis between two time intervals and was calculated between 0-6 months and 6-18 months as the primary outcome. The relationship of efficacy of epiphysiodesis with time intervals, bone segments, physeal coverage percentage by the screws, age and interscrew angle and physeal health was also assessed. A total of 11 patients' 17 bone segments (9 femurs and 8 tibias) with a mean age of 8.7 ± 2.3 were included. The mean efficacy of the epiphysiodesis in the first 6 months for femurs was 23 ± 20 % (range, 0-53%) and for tibias was 21 ± 19 % (range, 0-53%); between 6 and 18 months it was 27 ± 19 % (range, 0-56%) for femurs and 15 ± 19 % (range, 0-50%) for tibias. In the first 6 months, physeal coverage percentage by the screws (r = 0.503, P = 0.04) and age (r = -0.534, P = 0.027) had a strong correlation with the epiphysiodesis efficacy. Dual two-hole tension band plating has variable efficacy in the treatment of LLD. Age and physeal coverage percentage by the screws could be related to epiphysiodesis efficacy.

The Actions of IGF-1 in the Growth Plate and Its Role in Postnatal Bone Elongation

PURPOSE OF REVIEW

Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables. Bones grow in length by endochondral ossification in cartilaginous growth plates at ends of developing long bones. This review provides an updated overview of the important factors that influence this process.

RECENT FINDINGS

Insulin-like growth factor-1 (IGF-1) is the major hormone required for growth and a drug for treating pediatric skeletal disorders. Temperature is an underrecognized environmental variable that also impacts linear growth. This paper reviews the current state of knowledge regarding the interaction of IGF-1 and environmental factors on bone elongation. Understanding how internal and external variables regulate bone lengthening is essential for developing and improving treatments for an array of bone elongation disorders. Future studies may benefit from understanding how these unique relationships could offer realistic new approaches for increasing bone length in different growth-limiting conditions.

A comparison of screw versus drill and curettage epiphysiodesis to correct leg-length discrepancy

PURPOSE

To compare two common surgical techniques of epiphysiodesis: drill/curettage epiphysiodesis (PDED) versus cross screw epiphysiodesis (PETS). The hypothesis is that the two techniques have similar efficacy but demonstrate differences in length of hospital stay (LOS), time to return to activity and complication rates.

METHODS

A retrospective review of growing children and adolescents less than 18 years old who required an epiphysiodesis with leg-length discrepancy (LLD) of 2 cm to 6 cm with minimum two years of follow-up was conducted. Characteristics including age at surgery, gender, epiphysiodesis location, side, operative time, LOS and hardware removal were compared across treatment groups. LLD, expected growth remaining (EGR) and bone age were determined preoperatively and at most-recent visit. The correction ratio (change in EGR) was calculated along with a 95% confidence interval (CI) to assess if correction in leg length was achieved.

RESULTS

A total of 115 patients underwent epiphysiodesis in the femur (53%), tibia (24%) or a combination (24%). The cohort was 47% male, with a mean age of 12.6 years (7.7 to 17.7) at surgery. Median follow-up was 3.7 years (2.0 to 12.7). In all, 23 patients underwent PETS and 92 patients had PDED. Both treatment groups achieved expected LLD correction. There was no significant difference in median operative time, complication rates or LOS. PETS patients returned to activity at a mean 1.4 months (interquartile range (IQR) 0.7 to 2.1) while PDED patients returned at a mean 2.4 months (IQR 1.7 to 3) (p < 0.001).

CONCLUSION

Effectiveness in achieving expected correction, LOS and operative time are similar between screw and drill/curettage epiphysiodesis. Patients undergoing PETS demonstrated a faster return to baseline activity than patients with PDED.

LEVEL OF EVIDENCE

III.

Percutaneous Epiphysiodesis Using Transphyseal Screws: a Case Series Demonstrating High Efficacy

BACKGROUND

Percutaneous epiphysiodesis using transphyseal screws (PETS) has been associated with implant failure, implant prominence, angular deformities, and delayed growth inhibition.

QUESTIONS/PURPOSES

The aim of this study was to assess the complication rate and efficacy (defined as actual growth inhibition divided by expected growth inhibition) of PETS and to identify factors associated with improved efficacy.

METHODS

Patients who underwent distal femoral and/or proximal tibial PETS between January 2007 and June 2014 were identified. Complications, efficacy, and final limb-length discrepancy (LLD) were calculated using multipliers and inhibition rates based on previous growth. Associations between efficacy and screw insertion angle (SIA), body mass index, and number of threads crossing the physis were calculated.

RESULTS

Eight-two patients (126 treated physes) were included. The mean pre-operative LLD was 27.7 mm (SD = 7.5). Following epiphysiodesis, 15 had temporary pain (18%), five had temporary effusion (6.1%), four had broken implants (4.9%), four developed mild angulation (4.9%), and three had failed epiphysiodesis requiring revision (3.7%). Thirty-one underwent screw removal (n = 31, 38%). Mean LLD at maturity was 17.3 mm (SD = 5.8 mm). Mean efficacy at the distal femur was 97% (SD = 46%), at the proximal tibia was 108% (SD = 66%) and was 103% (SD = 57%) overall. Increased screw threads across the lateral proximal tibial physis (Spearman's correlation coefficient = 0.67; 95% CI = 0.40-0.94) and higher BMI (Spearman's correlation coefficient = 0.55; 95% CI = 0.34-0.77) were positively associated with increased efficacy.

CONCLUSIONS

The efficacy of PETS may be more favorable than previously reported. Only 3.7% had serious complications requiring revision epiphysiodesis, lower than previous reports. Attention to sufficient screw threads across the physis may be important in optimizing PETS results.

Closing the growth plate: a review of indications and surgical options

PURPOSE OF REVIEW

The purpose is to review the indications for epiphysiodesis in the treatment of pediatric limb length discrepancies; provide an update on current diagnostic, planning, and surgical techniques; and to introduce possible future alternatives.

RECENT FINDINGS

Retrospective comparative studies have failed to demonstrate superiority of one epiphysiodesis technique over the others. EOS low-dose biplanar X-ray and smartphone growth prediction applications are improving our ability to diagnose and plan treatment for leg length discrepancy. Arthroscopically guided percutaneous epiphysiodesis and radiofrequency ablation are newer techniques that are still under investigation.

SUMMARY

Epiphysiodesis is the treatment of choice for children with predicted leg length discrepancies between 2-5 cm, provided that the physes are open with sufficient growth remaining. The most common epiphysiodesis techniques are performed percutaneously and either ablate the physis with drills/curettes or use metal implants to tether the physis and prevent further growth. Surgical treatment is typically ambulatory in nature, and allows for early return to weight bearing. In modern series, complication rates are less than 10%, with the majority being minor complications. Further high-quality prospective research is needed to determine the optimal epiphysiodesis surgical technique.

Lower extremity growth and deformity

The pediatric lower extremity has well known growth patterns. When deformities or growth disturbances occur, there are several methods to measure and predict the resulting discrepancy, including the Green-Anderson, Moseley, and Multiplier methods. Many techniques exist to correct leg length discrepancy and deformity such and temporary epiphysiodesis, permanent epiphysiodesis, external fixators, and internal lengthening devices. All of these methods have numerous complications and limitations; however, with careful planning and patient selection, length and alignment can be improved with high patient satisfaction.

An improved spreadsheet for calculating limb length discrepancy and epiphysiodesis timing using the multiplier method

PURPOSE

The multiplier method is a technique to predict limb length discrepancy (LLD) at maturity in pediatric patients. Various tools have been developed for performing the multiplier calculations to predict LLD and timing of epiphysiodesis. These include multiplier/growth applications (apps) and a spreadsheet which have helped to facilitate LLC calculations in an efficient and easy manner. We have updated the spreadsheet to improve features for making LLD calculations and facilitate pasting data into electronic medical records (EMRs).

METHODS

Tools currently in use were critically examined for features that limited their function, created possible sources of error or could be more user-friendly. These features were modified and recreated in an improved Excel spreadsheet that uses patient age, sex, limb lengths, and previous lengthening surgeries as inputs to predict LLD at maturity and offer options for timing of epiphysiodesis for both congenital and developmental LLD. Our multiplier spreadsheet function was then compared to manual calculations and other multiplier tools for accuracy and ease of use.

RESULTS

Our spreadsheet accurately calculates LLD at maturity and timing of epiphysiodesis when compared to other methods. It contains a function to calculate predicted leg lengths after previous lengthenings, and concise single-page worksheets for developmental LLD, congenital LLD, and height prediction.

CONCLUSIONS

This spreadsheet was developed to provide a more efficient and user-friendly method of calculating LLD at maturity and timing of epiphysiodesis. It can easily be pasted into the EMR for ease of documentation. We recommend this method for both clinical practice and educational use.