Tension band plates have greater risks of complications in temporary epiphysiodesis

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.

Microwave Ablation of the Pig Growth Plate: Proof of Concept for Minimally Invasive Epiphysiodesis

BACKGROUND

Different surgical methods for epiphysiodesis of limb length discrepancy (LLD) have been described. Although these methods are variably effective, they are associated with morbidity (pain and limp) and potential complications. Microwave ablation is a less-invasive opportunity to halt growth by selectively destroying the growth plate via thermal energy to treat LLD in children.

QUESTIONS/PURPOSES

In this proof-of-concept study using an in vivo pig model, we asked: (1) What is the durability of response 2 to 4 months after microwave ablation of the tibial growth plate as measured by length and angulation of the tibia via a CT scan? (2) Was articular cartilage maintained as measured by standard histologic staining for articular cartilage viability?

METHODS

To develop an in vivo protocol for microwave ablation, we placed microwave antennas adjacent to the proximal tibia growth plate in the cadaveric hindlimbs of 18 3-month-old pigs. To determine the suitable time, we varied ablation from 90 to 270 seconds at 65-W power settings. After sectioning the tibia, we visually assessed for discoloration (implying growth plate destruction) that included the central growth plate but did not encroach into the epiphysis in a manner that could disrupt the articular surface. Using this information, we then performed microwave ablation on three live female pigs (3.5 to 4 months old) to evaluate physiologic changes and durability of response. A postprocedure MRI was performed to ensure the intervention led to spatial growth plate alterations similar to that seen in cadavers. This was followed by serial CT, which was used to assess the potential effect on local bone and growth until the animals were euthanized 2 to 4 months after the procedure. We analyzed LLD, angular deformity, and bony deformity using CT scans of both tibias. The visibility of articular cartilage was compared with that of the contralateral tibia via standard histologic staining, and growth rates of the proximal tibial growth plate were compared via fluorochrome labeling.

RESULTS

Eighteen cadaveric specimens showed ablation zones across the growth plate without visual damage to the articular surface. The three live pigs did not exhibit changes in gait or require notable pain medication after the procedure. Each animal demonstrated growth plate destruction, expected limb shortening (0.8, 1.2, and 1.5 cm), and bony cavitation around the growth plate. Slight valgus bone angulation (4º, 5º, and 12º) compared with the control tibia was noted. No qualitatively observable articular cartilage damage was encountered from the histologic comparison with the contralateral tibia for articular cartilage thickness and cellular morphology.

CONCLUSION

A microwave antenna placed into a pig's proximal tibia growth plate can slow the growth of the tibia without apparent pain and alteration of gait and function.

CLINICAL RELEVANCE

Further investigation and refinement of our animal model is ongoing and includes shorter ablation times and comparison of dynamic ablation (moving the antennae during the ablation) as well as static ablation of the tibia from a medial and lateral portal. These refinements and planned comparison with standard mechanical growth arrest in our pig model may lead to a similar approach to ablate growth plates in children with LLD.

Effects of tension band plating on coronal plane alignment of lower extremities in children treated for idiopathic limb length discrepancy

PURPOSE

One of the most common treatment methods for moderate limb length discrepancy in children is growth modulation using tension band plating. Coronal plane deformities after tension band plating for limb length discrepancy have been documented as an important complication in articles involving heterogeneous groups consisted of both idiopathic cases and patients with pathological physes. The aim of the study was to determine the rate of coronal plane deformities after treatment of a homogeneous group of idiopathic limb length discrepancy cases with tension band plating and to compare screw constructs of medial and lateral plates.

METHODS

Patient files were retrospectively reviewed for amount of limb length discrepancy, anatomical femorotibial angle, mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, and inter-screw angles of each plate on both sides of the tibiae and femora. Measurements at each follow-up period were compared to each other.

RESULTS

A total of 26 patient files (37 bones) were included to the study. The mean age was 10.5 years. The mean limb length discrepancy was 27.5 mm. Implants were removed after mean 34.5 months. The mean follow-up period was 58.5 months. There was no significant difference in inter-screw angle on each side of the bones at the time of implantation and in lower limb alignments during follow-up.

CONCLUSION

Treatment of mild-to-moderate idiopathic limb length discrepancy with tension band plating in children was found to be safe against any coronal plane deformity during follow-up until skeletal maturity.

LEVEL OF EVIDENCE

Level IV.