Guided growth for the treatment of moderate leg-length discrepancy

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.

Percutaneous transphyseal screw induces varus proximal femoral growth modulation in a growing pig model-A three-dimensional analysis

Bone and joint angular deformities are common pediatric orthopedic problems that are often corrected surgically. Previous studies successfully demonstrated proximal femoral growth modulation in animal models, however outcome measurements were limited by two-dimensional analysis. In this study, six Yorkshire cross male piglets were treated with unilateral percutaneous transphyseal screw placement across the medial aspect of the proximal femoral physis and analyzed using three-dimensional (3D) techniques. Three primary outcome measures were considered-physis angle, version, and femoral length. Compared to paired controls, all treated femurs displayed varus correction and shortening after an average treatment period of 10 weeks. The amount of varus change was 11.6 ± 2.8° (mean ± SD) (p = 0.0002, 95% confidence interval [CI] [8.659, 14.589]) and shortening was 4.3 ± 1.6 mm (p = 0.0011, 95% CI [2.672, 5.942]). Four animals demonstrated retroversion and two demonstrated anteversion compared to controls (4.1 ± 5.4° retroversion, p = 0.1169, 95% CI [-1.483, 9.765]). The amount of varus correction was strongly correlated with the orientation of the screw relative to the medial/lateral axis of the physis (r = -0.887, p = 0.0183, 95% CI [-0.988, -0.271]). The amount and direction of version was strongly correlated with how eccentrically anterior or posterior the screw was placed relative to the center of the physis (r = -0.850, p = 0.0322, 95% CI [-0.983, -0.123]) as well as the angle of the screw relative to the posterior condylar axis of the femur (r = -0.980, p = 0.0006, 95% CI [-0.998, -0.822]). This study is the first to use 3D analysis to quantify proximal femur growth modulation and identify associations between the growth modulation outcomes and screw placement parameters.

[Options and limits of leg length correction in paediatric orthopaedics]

For paediatric orthopaedic surgeons treating leg length discrepancy, knowledge of the available procedures and their options and limits is just as important as mastery of the very different surgical methods and implants, as well as the possible complications, in order to be able to advise and treat the children and adolescents and their parents comprehensively and in the best interests. Both the growth inhibiting procedures and the complex bone lengthening procedures require a great deal of experience to successfully guide patients and families through what is often a lengthy and sometimes complicated treatment process. Careful preoperative indications and planning, precise surgical techniques with suitable instruments and implants, and attentive postoperative check-ups are mandatory prerequisites for the desired therapeutic success.

Radiographic reference values of the central knee anatomy in 8-16-year-old children

BACKGROUND AND PURPOSE

For correction of leg-length discrepancy or angular deformity of the lower limb in skeletally immature patients temporary or permanent (hemi-)epiphysiodesis can be employed. These are reliable treatments with few complications. Recently, radiographic analysis of treatment-related alterations of the central knee anatomy gained interest among pediatric orthopedic surgeons. To date the comparison and adequate interpretation of potential changes of the central knee anatomy is limited due to the lack of defined standardized radiographic references. We aimed to establish new reference values of the central knee anatomy.

PATIENTS AND METHODS

A retrospective analysis of calibrated longstanding anteroposterior radiographs of 254 skeletally immature patients with a chronological age ranging from 8 to 16 years was conducted. The following radiographic parameters were assessed: (1) femoral floor angle, (2) tibial roof angle, (3) width at femoral physis, and (4) femoral notch-intercondylar distance.

RESULTS

All observed radiographic parameters were normally distributed with a mean age of 12.4 years (standard deviation [SD] 2, 95% confidence interval [CI] 12.2-12.6). Mean femoral floor angle was 142° (SD 6, CI 141.8-142.9), mean tibial roof angle was 144° (SD 5, CI 143.7-144.1), mean width at femoral physis was 73 mm (SD 6, CI 72.8-73.9), and mean femoral notch-intercondylar distance was 8 mm (SD 1, CI 7.5-7.7). The estimated intraclass correlation coefficient values were excellent for all measurements.

CONCLUSION

This study provides new radiographic reference values of the central knee anatomy for children between 8 and 16 years and we suggest considering values within the range of 2 SD as the physiological range.

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.

Design of a New "U"-shaped Staple and Its Clinical Application in Postoperative Ankle Valgus of Congenital Pseudarthrosis of the Tibia in Children

Objective

There has been a lack of suitable epiphysis blocking materials due to the characteristics of less tissue coverage and narrow epiphysis in children's distal tibial medial malleolus. Therefore, this study is to investigate the clinical efficacy and safety of a new “U”‐shaped staple in the treatment of postoperative ankle valgus of congenital pseudarthrosis of the tibia (CPT).

Method

According to the inclusion and exclusion criteria, 33 patients with postoperative ankle valgus of CPT were treated with new “U”‐shaped staples from May 2013 to September 2019. The deformity of ankle valgus was gradually corrected by implanting a new “U”‐shaped staple on the medial side of the distal tibia. Clinical indexes such as the operation time, intraoperative bleeding and hospital stay were observed. Tibiotalar angle was selected as the evaluation index of ankle valgus. American Orthopedic Foot & Ankle Society (AOFAS) scale was used for clinical evaluation of ankle function. The tibiotalar angle, deformity correction rate and complications were evaluated by preoperative, postoperative and last follow‐up imaging data. Student's t‐test was used for statistical analysis.

Results

Thirty‐three patients, including 12 males and 21 females were included. All the patients were followed up for at least 14 months, with an average of 35 months. The average operation time was 23 (15–40) min, the average amount of intraoperative bleeding was 7.5 (4–10) mL, and the average hospital stay was 4.2 (3–6) days. The intraoperative tibiotalar angles of all patients were 74.2° ± 4.6°, the tibiotalar angle were 86.8° ± 4.9° when internal fixation was removed, and the tibiotalar angles at the last follow‐up were 84.3° ± 5.9°. The average orthopedic rate was 0.68° per month. No patients suffered from serious complications such as screw prolapse, osteomyelitis, wound infection, etc. Postoperative wound pain complications occurred in two patients, which were relieved after conservative treatment. The AOFAS score improved from 46.2 ± 9.4 before the operation to 74.6 ± 5.7 at the last follow‐up (P < 0.01). The ankle movement was good without joint stiffness. There was no epiphyseal plate injury after the removal of internal fixation.

Conclusion

The new “U”‐shaped staple is characterized by simple implantation, low notch, lower risk of fixation failure and close fitting with cortical bone. It is a safe and effective internal fixation system for the treatment of ankle valgus in children.

Percutaneous epiphysiodesis using transphyseal screws (PETS) versus tension-band plating (TBP): comparative study of outcomes for correcting limb length discrepancy

OBJECTIVES

The best effective treatment strategy for limb length discrepancy (LLD) is still being debated. The goal of this study was to compare the efficacy and results of tension-band plating (TBP) and percutaneous epiphysiodesis using transphyseal screws (PETS) for LLD correction.

METHODS

From June 2008 to January 2019, children who had lower extremity epiphysiodesis with either TBP or PETS were reviewed retrospectively. At the conclusion of treatment, LLD, angular deformity, and complications were reviewed. The t-test or Wilcoxon rank sum test was used to compare continuous variables. Categorical variables were evaluated using Fisher's exact test or χ² test.

RESULTS

A total of 32 epiphysiodeses with TBP (14 patients, 24 femur/tibias) or PETS (13 patients, 23 femur/tibias) were compared. TBPs were conducted while the patients were younger (11.0 vs. 13.1 years, p = 0.005). The treatment durations were similar in both groups (TBP: 23.5 months vs. PETS: 24 months, p = 0.132). PETS had significantly shorter operative time (p = 0.047), length of hospital stay (p = 0.014), and time to return to full activity (p = 0.043). LLD in the TBP group reduced from 2.64 to 1.38 cm (p = 0.005), while in the PETS group it decreased from 2.76 to 1.08 cm (p = 0.001). During treatment, the rate of LLD correction 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). At the end of treatment, 8 TBP cases (47%) and 9 PETS cases (60%) had achieved LLD ≤ 2 cm (p = 0.502), and at the most recent follow-up, this had grown to 11 (65%) in the TBP group and 12 (80%) in the PETS group. There were no significant differences in the total number of complications between groups (p > 0.05). Revision surgery was required in 11 TBP and 3 PETS limbs due to persistent LLD or angular deformity (AD) (p = 0.016). Logistic regression did not reveal any significant association between TBP and the rate of complication or revision surgery.

CONCLUSION

PETS and TBP are both effective methods for limb length equalization. PETS, on the other hand, was linked to a shorter operative time, a shorter hospital stay, a faster recovery to pre-operative function, and a lower complication rate. The rate of revision surgery due to persistent LLD or AD was higher in TBP. We advise surgeons against utilizing TBP to correct LLD.

LEVEL OF EVIDENCE

III.

Growth arrest: leg length correction through temporary epiphysiodesis with a novel rigid staple (RigidTack)

AIMS

Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework.

METHODS

A cohort of 56 patients, including 45 unilateral EDs for LLD and 11 bilateral EDs for tall stature, were prospectively analyzed. ED was performed with 222 rigid staples with a mean follow-up of 24.4 months (8 to 49). Patients with a predicted LLD of ≥ 2 cm at skeletal maturity were included. Mean age at surgery was 12.1 years (8 to 14). Correction and complication rates including implant-associated problems, and secondary deformities as well as perioperative parameters, were recorded (IDEAL stage 2a). These results were compared to historical cohorts treated for correction of LLD with two-hole plates or Blount staples.

RESULTS

The mean LLD was reduced from 25.2 mm (15 to 45) before surgery to 9.3 mm (6 to 25) at skeletal maturity. Implant-associated complications occurred in 4/56 treatments (7%), and secondary frontal plane deformities were detected in 5/45 legs (11%) of the LLD cohort. Including tall stature patients, the rate increased to 12/67 legs (18%). Sagittal plane deformities were observed during 1/45 LLD treatments (2%). Compared to two-hole plates and Blount staples, similar correction rates were observed in all devices. Lower rates of frontal and sagittal plane deformities were observed using rigid staples.

CONCLUSION

Treatment of LLD using novel rigid staples appears a feasible and promising strategy. Secondary frontal and sagittal plane deformities remain a potential complication, although the rate seems to be lower in patients treated with rigid staples. Further comparative studies are needed to investigate this issue. Cite this article: Bone Joint J 2021;103-B(8):1428-1437.

Tension band plates have greater risks of complications in temporary epiphysiodesis

PURPOSE

This study aimed to compare the efficacy of decreasing leg-length discrepancy (LLD) and postoperative complications between tension band plates (TBP) and percutaneous transphyseal screws (PETS).

METHODS

This retrospective study reviewed LLD patients who underwent temporary epiphysiodesis at the distal femur and/or proximal tibia from 2010 to 2017 (minimum two years follow-up). Efficacy of decreasing LLD was assessed one and two years postoperatively. Complications were classified with the modified Clavien-Dindo-Sink complication classification system. Knee deformities were assessed by percentile and zone of mechanical axis across the tibial plateau.

RESULTS

In total, 53 patients (25 boys, 28 girls) underwent temporary epiphysiodesis (mean age, 11.4 years). The efficacy of decreasing LLD at two years between the TBP (n = 38) and PETS (n = 15) groups was comparable. Seven grade III complications were recorded in six TBP patients and in one PETS patient who underwent revision surgeries for knee deformities and physis impingement. Four grade I and two grade II complications occurred in the TBP group. The mechanical axis of the leg shifted laterally in the PETS group and medially in the TBP groups (+7.1 percentile versus -4.2 percentile; p < 0.05). Shifting of the mechanical axis by two zones was noted medially in four TBP patients and laterally in two PETS patients.

CONCLUSION

More implant-related complications and revision surgeries for angular deformities were associated with TBP. A tendency of varus and valgus deformity after epiphysiodesis using TBP and PETS was observed, respectively. Patients and families should be informed of the risks and regular postoperative follow-up is recommended.

LEVEL OF EVIDENCE

Level III.

Temporary Proximal Tibial Epiphysiodesis for Correction of Leg Length Discrepancy in Children-Should Proximal Fibular Epiphysiodesis Be Performed Concomitantly?

The need for concomitant proximal fibular epiphysiodesis (PFE) when correcting leg length discrepancy (LLD) with temporary proximal tibial epiphysiodesis (PTE) in children is controversially discussed. This single center, retrospective cohort study analyzes proximal fibular growth in patients treated by PTE with and without concomitant PFE. Radiographic measurements were conducted before implantation and at implant removal. The position of the fibular head in relation to the tibia was assessed with recently established radiographic reference values. All patients (n = 58, 19 females) received PTE to treat LLD at a mean age of 12.2 years (range 7 to 15). In 27/58 (47%) concomitant PFE was performed. Mean follow-up was 36.2 months (range 14.2 to 78.0). The position of the proximal fibula at implant removal was within physiological range in 21/26 patients (81%) with PFE and in 21/30 patients (70%) without PFE. Proximal fibular overgrowth newly developed in 2/26 patients (8%) treated with PFE and in 5/30 patients (17%) treated without PFE (p = 0.431). Peroneal nerve injury or discomfort due to proximal fibular overlength was not reported. The position of the proximal fibula should be critically assessed preoperatively under consideration of reference values before PTE. In consequence of this study, the authors do not routinely perform PFE concomitantly with PTE for correction of moderate LLD in children if the proximal fibula is localized within physiological radiographic margins determined by the established reference values.

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.

Surgical Indications in Hypophosphataemic Rickets

Low levels of phosphate in blood secondary to a lack of phosphorous reabsorption in the renal tubule cause hypophosphataemic rickets. To increase blood calcium levels, bone calcium is released into the bloodstream by increasing the activity of osteoclasts in the bones. These alterations in bone metabolism lead to delayed growth and small height, diffuse bone pain, bone fragility with microfractures, and frequent fractures and bone deformities. Although management of some of these conditions is mainly conservative, in cases of bone deformities or severe osteomalacia surgery should be considered: from minimally invasive surgical techniques of guided growth in patients with less deformity and open physeal cartilage to correction osteotomies in three-dimensional deformities. This article briefly reviews the indications for surgery procedures to be performed in these patients, highlighting when to use aggressive and non-aggressive approaches.

Comparison of Temporary Epiphysiodesis With RigidTacks™ and Blount-Staples in a Porcine Animal Model Using Magnetic Resonance Imaging

RigidTack™ is a newly developed implant for total temporary epiphyseodesis. The implant combines the technical advantages of the traditionally used rigid Blount-staples and the newer flexible eight-plates™. Thus, the implant is rigid like the Blount-staples, which may be a biomechanical advantage in temporary epiphyseodesis, and has an easy and guided implantation technique like the eight-plate™. As in eight-plates™, supposedly only two RigidTacks™ are sufficient for temporary epiphyseodesis compared to six Blount-staples in traditional treatment. The goal of this study was to compare Blount-staples and RigidTacks™ in regard to the total potential of growth arrest, the occurrence of postoperative implant-associated complications, secondary angular deformities, and central joint deformations. Twelve pigs were allocated in two groups (n = 6) for treatment of the proximal tibia. Total temporary epiphysiodesis was performed with either four Blount-staples or two RigidTacks™. Magnetic resonance imaging (MRI)-scans were performed before and 14 weeks after surgery, and the amount and distribution of growth arrest were evaluated by measuring the interphyseal distance in nine defined zones. Total temporary epiphysiodesis with two RigidTacks™ resulted in a similar amount of growth arrest as that of four Blount-staples. No significant coronal or sagittal angular deformities or joint deformities were observed in either group; however, one secondary loosening of a Blount-staple occurred. The study concluded that Blount-staples and RigidTacks™ are adequate implants for total temporary epiphysiodesis. Whether or not the precise implant-placement through the guided implantation technique of RigidTacks™ and a reduced number of implants indeed lead to a reduction of secondary angular deformities has to be investigated in further clinical trials. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 38:946-953, 2020.

Effects of Tibial Rotational-guided Growth on the Geometries of Tibial Plateaus and Menisci in Rabbits

BACKGROUND

There are studies on the use of oblique plate over epiphyses for rotational deformities but the effects of this method on bone are not yet known. The purpose of this study was to determine the effect and rebound effect of rotational-guided growth on the geometries of the tibial plateaus and menisci in a rabbit model of tibial axial rotation.

METHODS

Thirty male rabbits were 6 weeks old when medial and lateral plates were applied to the proximal tibias of the left side. After 4 weeks, 15 rabbits were euthanized (group 1), and the plates from the tibias of the remaining 15 rabbits (group 2) were removed. The rabbits in group 2 were euthanized 4 weeks later.

RESULTS

In the rabbits of group 1, the most striking differences were a decrease in the lateral tibial slope (from 28.3 to 10.8 degrees) and decrease in the ratio of the lateral plateau covered by the meniscus (from 71.9% to 61.3%). After removing the plates (group 2), the observed values of the rebound effects were 25.9 and 29.8 degrees for the lateral tibial slope, and 76.5% and 77.2% for the ratio of the lateral plateau covered by the meniscus. However, the meniscal geometries continued to change.

CONCLUSIONS

The rotational-guided growth provided by using plates caused a change in the tibial plateau geometry, and the rebound effect, except in the meniscal geometry, was observed after removing the plates in the growing period of the rabbits. Rotational-guided growth for the restoration of tibial axial rotation deformities may be suggested after determining the clinical effects of the increasing meniscal variables.

LEVEL OF EVIDENCE

Clinical relevance: the rotational-guided growth needs close follow-up because of possible changes in anatomy of the bone.

Biomechanical investigation of two long bone growth modulation techniques by finite element simulations

Implants used to correct pathological varus-valgus deformities (VVD) and leg length discrepancies (LLD) may not be optimized for the specific treatment, as suggested by their off-label use. Detailed analysis of this issue has been limited by the poorly understood mechanical behavior of the growing physis and ignorance of the loads acting on the implants. The aim of this study was to predict and compare the loading conditions of a growth modulation implant in VVD and LLD treatments. Idealized finite element (FE) models of the juvenile distal femur treated with the Eight-Plate implant were developed for VVD and LLD. Bone growth was simulated using thermal strains. The axial force in the plate was compared between the two treatments. Case-specific plate forces were predicted by virtually reproducing the screw deformation visible on radiographs of LLD (N = 4) and VVD (N = 4) clinical cases. The simple FE models reproduced the clinical implant deformations well. The resulting forces ranged from 129 to 580 N for the VVD patients. For LLD, this range was from 295 to 1002 N per plate, that is, 590-2004 N for the entire physis. The higher forces in LLD could be explained by restricted screw divergence in the double-sided implant application. For the first time, the loading conditions of a growth modulation implant were investigated and compared between two treatments by FE analyses, and the range of case-specific loads was predicted. These simulation tools may be utilized for guiding appropriate usage and for efficient development of implants. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1398-1405, 2018.

Comparing Percutaneous Physeal Epiphysiodesis and Eight-Plate Epiphysiodesis for the Treatment of Limb Length Discrepancy

BACKGROUND

Either percutaneous or eight-plate epiphysiodesis have been shown to be effective growth modulation techniques for the treatment of limb length discrepancies (LLD). However, few studies compared the outcomes of both techniques with some confounding results. The aim of this study was to evaluate the outcomes of the both techniques in the treatment of the LLD.

METHODS

Between 2004 and 2012, medical records of all cases that underwent either eight-plate or percutaneous epiphysiodesis (PE) were reviewed. Age at surgery, sex, diagnosis, surgical site (proximal tibia/distal femur), time of follow-up, complications, and additional procedures were noted. Correction of the LLD was evaluated to calculate the rate of correction and the percentage of improvement from the long-leg standing x-rays or scanograms, collected at each visit.

RESULTS

There were 24 patients in the eight-plate (10 girls and 14 boys) and 48 patients in the PE group (28 girls and 20 boys). No statistically significant difference was found in the age, sex, preoperative LLD, or follow-up between groups. Both groups reached to an average LLD below 2 cm. The percentage of improvement was significantly higher in the PE group (P=0.031). The rate of individual femoral and tibial correction did not differ between the groups.

CONCLUSIONS

Both methods are shown to be effective for LLD correction. However, PE led to greater improvement during the same follow-up time with fewer complications and less need for additional surgical procedures.

Paediatric lower limb deformity correction with the Eight Plate: adverse events and correction outcomes of 126 patients from an international multicentre study

No large multicentre studies have yet been published on tension-band-like implants such as the Eight Plate to treat limb-length discrepancies and varus valgus deformities in children. Therefore, we carried out a retrospective international multicentre study including 126 patients to assess outcomes and to reliably quantify the incidence of implant-related and growth-plate related adverse events (AEs). Correction was achieved in 66% of varus valgus deformities and in 59% of limb-length discrepancies and maintained in 85%. Twenty (18%) patients experienced 43 AEs, which were primarily screw-related. The AE rate of the Eight Plate is low; however, many of them could be avoided through tighter monitoring.

Effectiveness of different minimally invasive epiphysiodesis techniques in the management of pediatric leg length discrepancies: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to synthesize the best available evidence on the use of percutaneous epiphysiodesis for the management of pediatric leg length discrepancies (LLDs). The effectiveness of four different percutaneous epiphysiodesis techniques will be compared, including transphyseal screws (percutaneous epiphysiodesis using transphyseal screws), physeal drilling and curettage, physeal stapling and guided growth with eight-Plates.Specific review questions to be addressed include.

The role of guided growth as it relates to limb lengthening

For decades, the classic indication for limb lengthening has been reserved for anisomelia that was expected to reach or exceed 5 cm at maturity. Epiphysiodesis was reserved for discrepancies in the 2-5 cm range. With the increasing sophistication of fixators, including rail, hexapod, and hybrid, complex deformities may be corrected simultaneously while moderate to extreme lengthening is achieved. More recently, iterations of telescoping intramedullary rods have further strengthened our armamentarium. Meanwhile, permanent epiphysiodesis techniques, both open and percutaneous, have yielded to more versatile and reversible tethering of one (angle) or both (length) sides of a physis. While the techniques of guided growth and callotasis seem to be diametrically opposed, they may be used in a tandem or complementary fashion, for the benefit of the patient. If treatment is undertaken during skeletal growth, one must be aware that issues remain regarding the accurate assessment of skeletal maturity and prediction of the ultimate outcome. Therefore, there is potential for over- or undercorrection. Reversible and serial guided growth now enable the surgeon to commence intervention at a comparatively young age, for the purpose of optimizing limb alignment and reducing the ultimate discrepancy. Frame application may be delayed or, in some cases, avoided altogether. With the limb properly aligned at the outset of lengthening, elective use of a telescoping intramedullary nail may now be favored over a frame accordingly.

Limits of Growth Modulation Using Tension Band Plates in the Lower Extremities

Growth modulation using tension band plates (TBP) has been shown to be a safe, effective, and popular method for correcting pediatric frontal plane angular deformity around the knee. Recently, TBPs have been used to achieve reversible epiphysiodesis to treat limb-length discrepancy. Many surgeons have expanded the indications to include diagnoses other than frontal plane angular deformities, anatomic sites other than the knee, and correction of sagittal and oblique plane deformities. Despite the rapid acceptance of TBPs, the limits of this option have not been explored. We undertook a systematic literature review and found that the success rate for idiopathic cases approaches 100% with a low complication rate. Pathologic cases have a slightly lower success rate and a higher complication rate. The potential to avoid osteotomy with growth modulation makes TBPs a reasonable option for all but the most extreme pediatric frontal and sagittal plane lower extremity deformities. Applications to hip deformities remain unproven.

Rotational deformities of the long bones can be corrected with rotationally guided growth during the growth phase

Background and purpose - Coronal and sagittal plane long bone deformities can be corrected with guided growth, whereas transverse plane rotational deformities require osteotomy and internal or external fixation. We investigated whether rotational changes can be introduced with the plating technique. Methods - 45 rabbits (6 weeks old) were divided into 3 groups. The unoperated right tibia was used as control. In groups 1 and 3, two plates were placed obliquely to the long axis and in different directions. In group 2, a sham operation was performed with screws. Animals in groups 1 and 2 were followed for 4 weeks. In group 3 the implants were removed 4 weeks after the operation to observe rebound effect, and the animals were followed for another 4 weeks. The tibial torsion was assessed on computed tomography (CT). External rotation was accepted as a negative value. Results - In group 1, mean torsion was -20° (SD 7.9) in the right tibia and -2.9° (SD 7.2) in the left tibia (p < 0.001). In group 2, mean torsion was -23° (SD 4.9) in the right tibia and -26° (SD 6.5) in the left tibia (p = 0.2). In group 3, mean torsion was -21° (SD 6.3) in the right tibia and -9.5° (SD 5.3) in the left tibia (p < 0.001). Intergroup evaluation for left torsion showed a significant difference between group 2 and the other groups (p < 0.001). When the rebound effect was evaluated, there was no statistically significant difference between groups 1 and 3 (p = 0.08). Interpretation - A rotational change was attained with this technique. Although a rebound effect was seen after implant removal, it did not reach statistical significance. The final rotational change remained constant.

Prediction of Clinically Significant Leg-Length Discrepancy in Congenital Disorders

Leg-length discrepancy greater than 2 to 2.5 cm can potentially have an adverse effect on our walking and standing mechanisms and requires proper correction involving surgical treatment. However, for minor leg-length discrepancy in childhood, decision making for the indications for and timing of epiphysiodesis is difficult because of unpredictable final discrepancy. The purpose of this study was to analyze longitudinal changes of minor leg-length discrepancy in congenital disorders and to determine earlier predictive values for the clinically significant discrepancy. Twenty-one patients with congenital disorders who had minor leg-length discrepancy less than 2 cm at the first presentation were retrospectively evaluated. The patients were divided into 2 groups according to leg-length discrepancy at latest follow-up: the significant group (n=11) had 25 mm or more of leg-length discrepancy and the minor group (n=10) had less than 25 mm of leg-length discrepancy. The authors evaluated longitudinal changes of leg-length discrepancy within the first 10 years by mixed-effects regression model. All patients showed monotonically increasing leg-length discrepancy with age, except for 2 (neurofibromatosis type 1 and macrodactyly of the foot) who demonstrated fluctuating leg-length discrepancy. Mean annual rate of leg-length discrepancy change in the significant group was 2.1 mm across the first decade of life and was significantly larger than that in the minor group (difference in slope, 1.3 mm; P<.0001). In minor leg-length discrepancy associated with congenital disorders, the incidence of clinically significant leg-length discrepancy can be predictable by the annual rate of leg-length discrepancy change in the first decade of life.

[Special topics in pediatric orthopedics: options and limits of growth guidance]

BACKGROUND

A main task of pediatric orthopedics is the treatment of legs of different lengths or misshapen legs. Whereas for adult patients complicated and invasive operative interventions are necessary, the growth potential of the epiphysial plate can be utilized in childhood and adolescence to correct leg length differences and leg axis deformities.

THERAPY

Epiphysiodesis leads to a guidance of growth via a temporary or permanent and partial or complete blockade of the epiphysial plate depending on the indications. This method is principally a less invasive procedure with few complications.

CONCLUSION

Careful preoperative assessment of the indications and planning, precise operative technique and attentive postoperative control investigations are absolutely essential for successful treatment.