Mechanical axis following staple epiphysiodesis for limb-length inequality

The Influence of Temporary Epiphysiodesis of the Proximal End of the Tibia on the Shape of the Knee Joint in Children Treated for Leg Length Discrepancy

Background: Leg length discrepancy (LLD) is a common problem in the daily clinical practice of pediatric orthopedists. Surgical treatment using LLD temporary epiphysiodesis with eight-plate implants is a minimally invasive, safe, and well-tolerated procedure that provides good treatment effects with a relatively low percentage of complications. The main aim of this retrospective study was to determine the effect of epiphysiodesis on the shape of the proximal tibia. Methods: The retrospective study was based on medical records from 2010 to 2019. Radiographs taken before the epiphysiodesis and at 6-month intervals until the end of the treatment were investigated. A total of 60 patients treated for LLD were included in the study (24 girls, 36 boys). They were divided into three groups depending on the duration of the LLD treatment: group I (18 months), group II (30 months), and group III (42 months of treatment). Radiological parameters were assessed, including the roof angle (D), the slope angles (α and β), and the specific parameters of the tibial epiphysis, namely LTH (lateral tubercle height), MTH (medial tubercle height), and TW (tibial width). Results: The roof angle decreased in all the groups, which was accompanied by an increase in the β or α angle. LTH, MTH and TW also increased, and the differences before and after the treatment for the treated legs were statistically significant in all the studied groups. The greatest change in the shape of the articular surface of the proximal tibia occurred after 42 months of treatment. Conclusions: The study showed that epiphysiodesis affects the proximal tibial articular surface over prolonged treatment. Thus, there is a need for future long-term follow-up studies to elucidate the potential effects of LLD egalization.

[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.

Angular deformities after percutaneous epiphysiodesis for leg length discrepancy

PURPOSE

The purpose of this study was to systematically analyze the presence of secondary angular deformities after percutaneous epiphysiodesis based on long-standing radiographs, and to see if the occurrence and magnitude of angular deformities after percutaneous epiphysiodesis correlated with the amount of remaining growth at the time of surgery.

METHODS

From a local Health Register consisting of patients investigated using the Moseley Straight-Line Graph, we identified 269 patients who had undergone percutaneous epiphysiodesis from 2002 until 2020. Radiographic analysis included the measurement of mechanical axis and joint orientation angles on long-standing anterior-posterior radiographs. Remaining growth was analyzed based on the Menelaus method.

RESULTS

One hundred and forty epiphysiodeses (71 femurs and 69 tibiae) in 88 patients (39 girls and 49 boys) could be included in the study. Mean age at surgery was 13.2 (10-16.8) years, and mean skeletal age at surgery was 13.0 (9.8-15.7) years. A change of the MA (Mechanical axis) ≥10 mm was found in eight patients (9%). Secondary frontal plane deformities after percutaneous epiphysiodesis correlated significantly with the remaining growth at the time of surgery (p = 0.003).

CONCLUSION

We found a high rate of secondary angular deformities after percutaneous epiphysiodesis, and the magnitude of the deformities correlated with the amount of remaining growth at the time of surgery. A modification of the original surgical method for percutaneous epiphysiodesis to also include ablation of central parts of the growth plate might be considered. Patients should be enrolled in a systematic follow-up scheme which allows for the early detection of possible angular deformities.

LEVEL OF EVIDENCE

level III study.

Application of three-dimensional printed navigation templates to correct lower limb deformities in children by the guided growth technique

Objective

Currently, individualized navigation templates are rarely applied in pediatric orthopedic surgery. This study aimed to explore the potential of navigation templates obtained using computer-aided design and three-dimensional (3D) printing to correct lower limb deformities in children by the guided growth technique.

Methods

We prospectively studied 45 children with leg length discrepancy (LLD) or lower limb angular deformities, who underwent guided growth surgery involving 8-plate. In total, 21 and 24 children were included in the navigation template (group A) group and in the traditional surgery (group B) group, respectively. Mimics software was used for designing and printing navigation templates. The operation time, X-ray radiation exposure, damage to cartilage, and postoperative complications were recorded.

Results

The mean operation time in groups A and B were 20.78 and 28.39 min, respectively, and the difference was statistically significant. Compared with group B, the intraoperative exposure of X-rays in group A was reduced by 25% on average. After 9–24 months of follow-up, the deformities were corrected in both groups. No significant differences in the treatment effect were noted between the groups, and no complications occurred.

Conclusions

Using the individualized navigation template in the guided growth technique made the surgical procedure convenient and simple to perform. In addition, the operation time and intraoperative exposure to X-rays were reduced. We consider that 3D printed navigation templates can facilitate the accurate completion of corrective surgeries for lower limb deformities in children, which is worthy of promotion and application.

Genu Valgum After Distal Femur Extension Osteotomy in Children With Cerebral Palsy

BACKGROUND

Distal femur extension osteotomy (DFEO) is a common treatment for knee flexion contracture and crouch gait in patients with cerebral palsy (CP), but skeletally immature patients tend to develop genu valgum deformities after DFEO. This study aimed to report the tendency of valgus changes after DFEO and determine the risk factors for subsequent surgery for excessive genu valgum.

METHODS

This retrospective case-control study included 25 children with CP who underwent DFEO in 44 limbs for knee flexion contractures ≥15 degrees at a mean age of 11.0 years. Radiologic measurements included the anatomic lateral distal femoral angle (aLDFA), anatomic tibiofemoral angle (aTFA), medial proximal tibia angle, and plate-condyle angle, postoperatively and at the latest follow-up. Age, sex, preoperative knee flexion contracture angle, Gross Motor Function Classification System level, and radiographic measurements were compared between children with and without subsequent guided growth for genu valgum.

RESULTS

A significant valgus change was observed at the distal femur in the first postoperative year (aLDFA from 83.6 to 80.1 degrees, P<0.001; aTFA from 176.1 to 172.5 degrees, P<0.01; plate-condylar angle from 5.3 to 9.5 degrees, P<0.001). Valgus changes occurred in 36 of the 44 limbs (82%) by an average of -4.6 degrees in the aLDFA, and subsequent guided growth was performed in 5 patients (20%). Guided growth for genu valgum was associated with a greater postoperative valgus angle (aLDFA: 78.0 vs. 84.9 degrees, P<0.01) but not with age, Gross Motor Function Classification System level, or preoperative flexion contracture.

CONCLUSIONS

Distal metaphyseal osteotomies and distally placed angled plates near the physis are associated with valgus changes following growth. We recommend making a slight varus alignment during DFEO to compensate for subsequent valgus changes.

LEVEL OF EVIDENCE

Level III-therapeutic, retrospective comparative study.

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.

Comparison of two types of fixation for proximal tibial epiphysiodesis: An experimental study in a rabbit model

Objectives

In this study, we describe a novel hemiepiphysiodesis technique to prevent implant-related perichondrial ring injury in a rabbit model.

Materials and methods

Proximal tibial epiphyseal plates of a total of 16 white New Zealand rabbits were used for this animal model. The subjects were divided into three equal groups as follows: Group 1 (Kirschner wire [K-wire]/cerclage), Group 2 (8-plate) right-hind legs, Group 3 (Control) left hind legs. Using anteroposterior radiography, the medial slope angle (MSA), articular line-diaphyseal angle (ALDA), and the angle between screws of 8-plate in lateral X-ray tibial slope angle (TSA) were measured. The radiographs were taken early postoperative (Day 1) and on sacrification day (Week 8). The histological evaluation of the perichondrial ring was made on a 7-mm axial section that stained with Safranin O/fast green at X10 magnification.

Results

In both K-wire and 8-plate groups, the early postoperative ALDA and TSA were greater than the sacrification ALDA and TSA (p=0.028 and p<0.001, respectively). The early postoperative MSA was lower than the sacrification MSA in groups, (p<0.001). The MSA in the control group was lower than the K-wire and 8-plate groups (p<0.001 and p=0.009; respectively). The perichondrial ring thickness of the K-wire group was greater than the 8-plate group in histological evaluation (p<0.001).

Conclusion

Both of the K-wire and 8-plate groups showed similar angulation effects in the proximal tibia, although histologically less damage to the perichondrial ring was observed in the K-wire group, compared to the 8-plate group.

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.

Epiphysiodesis for the treatment of tall stature and leg length discrepancy

Painful orthopedic conditions associated with extreme tall stature and leg length discrepancy (LLD) include back pain and adopting bad posture. After failure of conservative treatment options, blocking of the growth plates (epiphysiodesis) around the knee emerged as gold standard in patients with tall stature and LLD in the growing skeleton. Surgical planning includes growth prediction and evaluation of bone age. Since growth prediction is associated with a certain potential error, adequate planning and timing of epiphysiodesis are the key for success of the treatment. LLD corrections up to 5 cm can be achieved, and predicted extreme tall stature can be limited. Percutaneous epiphysiodesis techniques are minimally invasive, safe and efficient methods with low complication rates. In general, a multidisciplinary approach should be pursued when treating children and adolescents with tall stature.

Leg Length Discrepancy- Treatment Indications and Strategies

BACKGROUND

Many people have leg-length discrepancies of greater or lesser severity. No evidence-based studies on the need for treatment are currently available.

METHODS

This review is based on publications retrieved by a selective search in the PubMed database, as well as on published recommendations from Germany and abroad and on the authors' own clinical experience.

RESULTS

If the two legs are of different lengths, this is generally because one leg is too short. It is debated whether leg-length discrepancy causes pain or long-term musculoskeletal disturbances. A direct connection to back pain is questionable, but a mildly elevated incidence of knee arthritis seems likely. The evidence base on the indications for treatment of leg-length discrepancy is poor; only informal consensus recommendations are available. There are a wide variety of conservative and surgical treatment options. The final extent of a leg-length discrepancy first noted during the growing years can be estimated with predictive algorithms to within 2 cm. The treatments that can be considered include a shoe insert, a high shoe, or an orthosis, surgically induced slowing of growth by blockade of the epiphyseal plates around the knee joint, or leg lengthening with osteotomy and subsequent distraction of the bone callus with fully implanted or external apparatus. Changes in leg length exert marked mechanical stress on the soft tissues. If the predicted leg-length discrepancy exceeds 5 cm, initial leg-lengthening treatment can already be considered during the patient's growing years.

CONCLUSION

It must be discussed with each patient individually whether the treatment should be conservative or surgical. The extent of the discrepancy is not the sole determining factor for the mode of treatment. The decision to treat is always elective.

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.

Hemiepiphysiodesis using 2-holed reconstruction plate for correction of angular deformity of the knee in children

Background

This study assesses the outcome of hemi epiphysiodesis with a 2-holed reconstruction plate using the tension band principle in angular deformities of the knee and variables influencing the outcome.

Methods

Prospective study from 2012 to 2016 included 23 children with coronal deformities of the knee joint. IMD, ICD, BMI, mLDFA, mMPTA, mTFA, Mechanical axis deviation, Perpendicular mechanical axis ratio, and screw angle measured. Correction and rate of correction compared with BMI, age, etiology, PMAR and MAD, deformity, a segment of bone and the screw angle.

Results

Total 65 segments operated in 23 children with 40 knees. Out of the total 65, 36 plates were kept in distal femur physis and 29 in the proximal tibial physis. Thirteen knees had genu varum and 27 had genu valgum. The mean age at the time of surgery was 11.25 months. The mean follow-up of 36 months and the average time for correction was 18.64 months. 77.5% correction achieved with ROC maximum in the initial 6 months. ROC in TFA per year were 7.8⁰(femur), 5⁰(tibia), and 12⁰(femur with tibia). Complications included broken implant, screw back out, screw irritation and rebound phenomenon.

Conclusions

2-holed reconstruction plate gives similar correction to that of the 8-plate within a comparable period without additional complications. It has the advantage of being cost effective and readily available. Age, BMI, type of deformity, amount of initial deformity, do not play a significant role in the outcome of correction. Screw placement may have a role in the final correction of the deformity.

Level of evidence

Level 3.

Long-term results and comparison of the Green-Anderson and multiplier growth prediction methods after permanent epiphysiodesis using Canale's technique

PURPOSE

The aim of the study was to evaluate the accuracy and radiographic outcomes of Canale's method in patients with idiopathic leg-length discrepancy (LLD) following percutaneous epiphysiodesis. The accuracy of two common growth prediction methods was assessed.

METHODS

A total of 18 patients with 26 affected bones (eight distal femur, two proximal tibia, five combined) were clinically and radiologically analyzed after reaching skeletal maturity. We compared the final effect of epiphysiodesis at maturity with the expected effect of epiphysiodesis before surgery; these measures were calculated using the Green-Anderson and multiplier methods, respectively. We furthermore compared pre- and postoperative frontal and lateral plane radiographs.

RESULTS

The average LLD was 21.2 mm before surgery and 7.9 mm after epiphysiodesis. The final effect of both methods was not significantly different compared with the expected effect of epiphysiodesis before surgery. However, the prediction by the Green-Anderson method was closer to the definitive epiphysiodesis effect. The frontal plane radiographic deformity parameters did not change significantly after epiphysiodesis. The postoperative sagittal plane radiographic deformity parameters were in the normal range.

CONCLUSION

The Canale technique is a reliable method to reduce LLD in children. With regards to growth prediction, the Green-Anderson method using bone age seems to be more accurate than the multiplier method using chronological age. However, a relative over-estimation was observed with both methods in several cases, which might result in an insufficient correction.

LEVEL OF EVIDENCE

IV, Therapeutic study.

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.

Tension band plating is less effective in achieving equalization of leg length

PURPOSE

Little data is available on the efficiency of different implants for epiphysiodesis. The purpose of this study is to compare the efficacy between plates and staples in decreasing leg-length discrepancy.

METHODS

A retrospective review of 19 children who underwent temporary epiphysiodesis of the legs was conducted, with a minimum of two years of follow-up. The bone length and length ratio to the short side were measured at six months, one year and two years postoperatively. The change in discrepancy was compared between staples and plates by an independent t-test, and the shortest time to a significant decrease in discrepancy was determined using a paired t-test.

RESULTS

Ten patients underwent 13 staple procedures in nine femurs and four tibias for a 2.8-cm discrepancy at age 11.8 years, and nine patients underwent 14 plate procedures in seven femurs and seven tibias for a 3.1-cm discrepancy at age 12.4 years. Patients were followed up to skeletal maturity, except two. The use of staples decreased the discrepancy in the bone ratio from +4.8% to +1.2% in two years, and the use of plates decreased this ratio from +5.1% to +3.3% in two years. The change in the length ratio was significantly greater after stapling. Six months were required after stapling before the first significant decrease in discrepancy; it took two years after plating.

CONCLUSIONS

This study showed a significantly lower efficacy for decreasing leg-length discrepancy by tension band plating. Orthopaedic surgeons should be aware of the limitations of using plates for suppressing bone growth.

LEVEL OF EVIDENCE

III.

Anterior distal femoral hemiepiphysiodesis can reduce fixed flexion deformity of the knee: a retrospective study of 83 knees

Background and purpose - Fixed knee flexion deformity in children is a common problem in various diseases including myelomeningocele and cerebral palsy. Until now, only a few studies focusing on the surgical procedure of anterior distal femoral hemiepiphysiodesis have been published. We analyzed outcome and correction rate in the largest case series to date of patients treated by staples or 8-plates. Patients and methods - We reviewed the medical records of all patients with fixed knee flexion deformity who were treated with anterior distal femoral hemiepiphysiodesis using either staples or 8-plates between the years 2002 and 2017 (73 patients; 130 knees). 49 patients (83 knees) had completed treatment with implant removal at the time of full correction of the deformity or at skeletal maturity and were included. The average age at operation was 12 years (6-20). Patients were assigned to 3 different groups based on their diagnosis: cerebral palsy, myelomeningocele, and the "other" group.d Results - Mean fixed knee flexion deformity improved from 21° (10-60°) to 8° (0-50°) (p < 0.001) with an average correction rate of 0.44° per month (range -2.14° to 1.74°). The correction rate per month was lowest for patients with cerebral palsy (0.20°), followed by the myelomeningocele group (0.50°), and the "other" group (0.58°). Implant loosening occurred in 10% of the treated knees with consecutive re-implantation in 5% of the cases. Interpretation - Anterior distal femoral hemiepiphysiodesis is an effective and safe method for the treatment of fixed knee flexion deformity in children. The optimal timing depends on the remaining individual growth potential, the underlying disease, and the extent of the deformity.

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.

Guided growth: mechanism and reversibility of modulation

In paediatric orthopaedics, deformities and discrepancies in length of bones are key problems that commonly need to be addressed in daily practice. An understanding of the physiology behind developing bones is crucial for planning treatment. Modulation of the growing bone can be performed in a number of ways. Here, we discuss the principles and mechanisms behind the techniques. Historically, the first procedures were destructive in their mechanism but reversible techniques were later developed with stapling of the growth plate being the gold standard treatment for decades. It has historically been used for both angular deformities and control of overall bone length. Today, tension band plating has partially overtaken stapling but this technique also carries a risk of complications. The diverging screws in these implants are probably mainly useful for hemiepiphysiodesis. We also discuss new minimally invasive techniques that may become important in future clinical practice.

Bone growth resumption following in vivo static and dynamic compression removals on rats

Mechanical loadings influence bone growth and are used in pediatric treatments of musculoskeletal deformities. This in vivo study aimed at evaluating the effects of static and dynamic compression application and subsequent removal on bone growth, mineralization and neuropathic pain markers in growing rats. Forty-eight immature rats (28 days old) were assigned in two groups (2- and 4 weeks experiment duration) and four subgroups: control, sham, static, and dynamic. Controls had no surgery. A micro-loading device was implanted on the 6th and 8th caudal vertebrae of shams without loading, static loading at 0.2 MPa or dynamic loading at 0.2 MPa ± 30% and 0.1 Hz. In 2-week subgroups, compression was maintained for 15 days prior to euthanasia, while in 4- week subgroups, compression was removed for 10 additional days. Growth rates, histomorphometric parameters and mineralization intensity were quantified and compared. At 2 weeks, growth rates and growth plate heights of loaded groups (static/dynamic)were significantly lower than shams (p b 0.01).However, at 4 weeks, both growth rates and growth plate heights of loaded groups were similar to shams. At 4 weeks, alizarin red intensity was significantly higher in dynamics compared to shams (p b 0.05) and controls (p b 0.01). Both static and dynamic compressions enable growth resumption after loading removal, while preserving growth plate histomorphometric integrity. However, mineralization was enhanced after dynamic loading removal only. Dynamic loading showed promising results for fusionless treatment approaches for musculoskeletal deformities.

[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.

Quality-controlled dose reduction of full-leg radiography in patients with knee malalignment

OBJECTIVE

Digital plain radiographs of the full leg are frequently performed examinations of children and young adults. Thus, the objective of this work was to reduce the radiation exposure dependent on specific indications, and to determine objective quality-control criteria to ensure accurate assessment.

MATERIALS AND METHODS

Institutional review board approval and informed consent of all participants were obtained. In this prospective, randomized controlled, blinded, two-armed single-center study, 288 evaluable patients underwent plain radiography of the full leg with standard and reduced doses. The evaluation of the plain radiographs was conducted using the following criteria: mechanical axis, leg length, and maturation of the epiphyseal plate. Two blinded radiologists evaluated these criteria using a score ranging from 1 (definitely assessable) to 4 (not assessable). If a single criterion had been evaluated with a score of 3 or more points or all criteria with 2 points, the radiograph was scored as "not assessable". The study was designed as a non-inferiority trial.

RESULTS

Eleven (3.8%) examined X-rays were scored as not assessable. The rate of non-assessable radiographs with 33% reduced dose was significantly not inferior to the rate of non-assessable radiographs with standard dose. The evaluation of the quality criteria was dose independent.

CONCLUSIONS

Full-leg plain radiography in patients with knee malalignment can be performed at 33% reduced dose without loss of relevant diagnostic information.

Temporary epiphyseodesis for limb-length discrepancy. 8- to 15-year follow-up of 34 children

BACKGROUND AND PURPOSE

For the treatment of leg-length discrepancies (LLDs) of between 2 and 5 cm in adolescent patients, several epiphyseodesis options exist and various complications have been reported. We reviewed the 8- to 15-year outcome after temporary epiphyseodesis in patients with LLD.

PATIENTS AND METHODS

34 children with LLD of up to 5 cm were included in the study. Mean age at epiphyseodesis was 12.8 (10-16) years. Temporary epiphyseodesis was performed with Blount staples or 8-plates. The LLD was reviewed preoperatively, at the time of implant removal, and at follow-up. Every child had reached skeletal maturity at follow-up. Long-standing anteroposterior radiographs were analyzed with respect to the mechanical axis and remaining LLD at the time of follow-up. Possible complications were noted.

RESULTS

The mean LLD changed from 2.3 (0.9-4.5) cm to 0.8 (-1.0 to 2.6) cm at follow-up (p<0.001). 21 patients had a final LLD of <1 cm, and 10 had LLD of <0.5 cm. At the time of follow-up, in 32 patients the mechanical axis crossed within Steven's zone 1. No deep infections or neurovascular lesions were seen. 4 implant failures occurred, which were managed by revision.

INTERPRETATION

Temporary epiphyseodesis is an effective and safe option for the treatment of LLD. The timing of the procedure has to be chosen according to the remaining growth, facilitating a full correction of the LLD. If inaccurate placement of staples is avoided, substantial differences between the mechanical axes of both legs at skeletal maturity are rare.

Post-operative delay in return of function following guided growth tension plating and use of corrective physical therapy

PURPOSE

Guided growth has long been used to treat growth deformities, but the Eight-Plate(®) system has recently become more widely used by pediatric orthopaedists. Because the current literature lacks evaluation of functional status in the immediate post-operative period, we investigated functional status following use of the Eight-Plate(®) system.

METHODS

We evaluated post-operative delay in return of function following treatment with the Eight-Plate(®) system at two weeks after surgery. Fifty-one consecutive patients with a growth deformity were treated with the Eight-Plate(®) system. Patients were comprised of 32 male and 19 female patients with an average age of 11 years (range 2-17.9 years).

RESULTS

Among study participants, 19 patients (37.3 %) had post-operative delay of function. The rate of delayed function for patients 10 years of age or younger and 11 years of age or older was respectively 11.8 and 50 % (P = 0.002). Six of the 19 patients were treated with four or more plates, of which five patients (83.3 %) developed delayed return of function. The rate of delayed function in patients with at least one femoral plate compared to no femoral plate was respectively 45 and 9.1 % (P = 0.006). Bilateral operations were associated with a 66.7 % rate of delayed function compared to 25 % with unilateral operations (P = 0.004). When patients with delay of function were treated with physical therapy, 12 of 13 patients (92.3 %) had complete resolution of their symptoms.

CONCLUSION

Statistical significance demonstrated that patients at the greatest risk were 11 years of age or older, with four or more plates, with femoral plates, or with bilateral operations. Patients with delayed function were readily corrected by physical therapy.

Guiding femoral rotational growth in an animal model

BACKGROUND

Guided growth is most commonly utilized about the knee and ankle for the correction of coronal-plane deformities by the use of plates positioned perpendicular to the physis. Sagittal-plane deformity correction has been described as well. The purpose of our study was to examine the ability to affect axial-rotational growth. Our hypothesis was that placement of plates in an oblique orientation relative to the physis can induce rotational growth deformity.

METHODS

Our hypothesis was tested with use of a mathematical model and a bone model and subsequently in a rabbit model. Thirteen six-week-old rabbits underwent a rotational guided growth procedure involving the distal aspect of the right femur, with a sham procedure performed on the left side. Two plates were positioned in an oblique orientation relative to the physis, medially and laterally, to guide either internal or external rotational growth. After the rabbits were killed six weeks after the surgery, the femoral rotational profile was assessed by computed tomography scans of the dissected femora and the growth plates were examined histologically.

RESULTS

A significant effect on the rotational profile was found in the treated femora. When the plates were positioned to guide external rotation, the rotational profile was significantly greater in the treated femora (29.0° compared with 11.3° in the sham femora; p = 0.008). There was a positive linear correlation between the right-left difference in rotational profile and the change in inter-plate angle (R2 = 0.72, p = 0.001). Every 1° of inter-plate angle change induced 0.367° of rotational profile difference (p = 0.001). Histologically, a swirling effect of the physeal cell columns was seen in the treated femora.

CONCLUSIONS

Guided growth using plates was demonstrated to alter axial-rotational growth in a predictable fashion in a rabbit model.

CLINICAL RELEVANCE

Guided growth using plates may be effective for correction of rotational and multiplanar deformities.

The accuracy of current methods in determining the timing of epiphysiodesis

We compared the accuracy of the growth remaining method of assessing leg-length discrepancy (LLD) with the straight-line graph method, the multiplier method and their variants. We retrospectively reviewed the records of 44 patients treated by percutaneous epiphysiodesis for LLD. All were followed up until maturity. We used the modified Green–Anderson growth-remaining method (Method 1) to plan the timing of epiphysiodesis. Then we presumed that the other four methods described below were used pre-operatively for calculating the timing of epiphysiodesis. We then assumed that these four methods were used pre-operatively. Method 2 was the original Green–Anderson growth-remaining method; Method 3, Paley’s multiplier method using bone age; Method 4, Paley’s multiplier method using chronological age; and Method 5, Moseley’s straight-line graph method. We compared ‘Expected LLD at maturity with surgery’ with ‘Final LLD at maturity with surgery’ for each method. Statistical analysis revealed that ‘Expected LLD at maturity with surgery’ was significantly different from ‘Final LLD at maturity with surgery’. Method 2 was the most accurate. There was a significant correlation between ‘Expected LLD at maturity with surgery’ and ‘Final LLD at maturity with surgery’, the greatest correlation being with Method 2. Generally all the methods generated an overcorrected value. No method generates the precise ‘Expected LLD at maturity with surgery’. It is essential that an analysis of the pattern of growth is taken into account when predicting final LLD. As many additional data as possible are required.

Cite this article: Bone Joint J 2013;95-B:993–1000.

Controlled longitudinal bone growth by temporary tension band plating

Permanent growth arrest of the longer bone is an option in the treatment of minor leg-length discrepancies. The use of a tension band plating technique to produce a temporary epiphysiodesis is appealing as it avoids the need for accurate timing of the procedure in relation to remaining growth. We performed an animal study to establish if control of growth in a long bone is possible with tension band plating. Animals (pigs) were randomised to temporary epiphysiodesis on either the right or left tibia. Implants were removed after ten weeks. Both tibiae were examined using MRI at baseline, and after ten and 15 weeks. The median interphyseal distance was significantly shorter on the treated tibiae after both ten weeks (p = 0.04) and 15 weeks (p = 0.04). On T1-weighted images the metaphyseal water content was significantly reduced after ten weeks on the treated side (p = 0.04) but returned to values comparable with the untreated side at 15 weeks (p = 0.14). Return of growth was observed in all animals after removal of implants.

Temporary epiphysiodesis can be obtained using tension band plating. The technique is not yet in common clinical practice but might avoid the need for the accurate timing of epiphysiodesis.

Cite this article: Bone Joint J 2013;95-B:855–60.

Guided growth for the treatment of moderate leg-length discrepancy

The purpose of this study was to evaluate the effectiveness and complication rate of guided growth for the treatment of patients with a moderate leg-length discrepancy. The authors retrospectively reviewed all patients treated with guided growth for a moderate leg-length discrepancy at their institution between October 2004 and December 2010. Thirty-four patients met the inclusion criteria from an initial cohort of 105 patients. All patients were followed until screw removal or maturity occurred. Nine patients had a developmental leg-length discrepancy, and 25 had a congenital leg-length discrepancy. Average age was 12.6 years (range, 7-16 years). Average leg-length discrepancies, as measured on standing long-leg radiographs from the top of the pelvis, the top of the femoral heads, and the center of the ankle to the top of the femoral heads, were 22, 19, and 17 mm, respectively. Average discrepancies at screw removal or maturity were 13, 10, and 11 mm, respectively. Twenty of 33 patients had a leg-length discrepancy of less than 1 cm at maturity or screw removal. The leg-length discrepancy change in patients who underwent guided growth of the tibia was minimal. Leg-length discrepancies in patients who underwent guided growth of the femur or both the femur and the tibia changed by an average of 10 mm. One patient had a mechanical axis change greater than 1 zone, and 1 patient required treatment for angular deformity after being treated for a leg-length discrepancy. Guided growth is a safe and effective technique for treating moderate leg-length discrepancies.

Treatment of fixed knee flexion deformity by anterior distal femoral stapling

PURPOSE

The treatment of fixed knee flexion deformity through anterior distal femoral stapling has been investigated in only two studies so far, with promising results. The aim of the present study was to determine whether this technique might improve fixed knee flexion deformity in a series of growing children and adolescents with different conditions. Follow-up examinations were continued after staple removal in terms of a possible impairment of this deformity.

METHODS

We reviewed the medical records of all patients with fixed knee flexion deformity who had been treated by anterior distal femoral stapling at our institution. Twenty patients (37 knees) with a mean age of 12.7 years met the inclusion criteria (>12 months of follow-up; no additional procedures to correct fixed knee flexion deformity such as hamstring lengthening or posterior capsulotomy) and were evaluated in this study.

RESULTS

The mean fixed knee flexion deformity significantly improved from 21.4° (SD = 11.6) preoperatively to 7.0° (SD = 9.8) after a mean follow-up of 35.3 months. Young patients (<12 years) revealed superior improvement of this deformity, and especially children with distinct fixed knee flexion deformity of 30° or greater had benefit from early treatment. Impairment of flexion deformity was only seen in one patient (2 knees) after staple removal.

CONCLUSIONS

Our results demonstrate that anterior distal femoral stapling is an effective method for the treatment of fixed knee flexion deformity in growing children and adolescents. Rare complications, immediate mobilization, and a low recurrence rate after staple removal provide obvious advantages of this minimally invasive procedure.

LEVEL OF EVIDENCE

Retrospective therapeutic study, Level IV.

Vertebral body growth during growing rod instrumentation: growth preservation or stimulation?

STUDY DESIGN

Retrospective review, case series.

OBJECTIVE

Determination of whether growing rod treatment with routine lengthening every 6 months causes growth stimulation of individual vertebrae within instrumentation levels (WIL).

SUMMARY OF BACKGROUND DATA

The Hueter-Volkmann law states that distractive forces exerted upon growing physes stimulate growth and vice versa, a principle that has been in clinical use for decades. In previous studies, it has been shown that vertebral endplates might respond in a similar manner to distraction. It has been proven that fusionless instrumentation, which is the mainstay of treatment after failure of conservative measures for early-onset scoliosis, allows near-normal vertebral growth but the issue of how individual vertebrae respond to distraction has not yet been analyzed.

METHODS

This institution's database, including the radiographic data for growing rod patients, was analyzed retrospectively. Vertebral level heights within and outside instrumentation levels were measured in postindex and postfinal follow-up x-rays, and the amount of growth that has taken place in a minimum follow-up period of 2 years was calculated and then compared for statistical significance.

RESULTS

Twenty patients (6 M, 14 F, average age, 71.0 mo) met the inclusion criteria. The average follow-up was 49 months (range, 26 to 72 mo). Lengthenings were performed every 6 months regularly. The average height of vertebrae WIL was 15.9 mm (range, 10.0 to 21.1 mm) in postindex and 22.9 mm (range, 15.0 to 32.9 mm) in the final follow-up; vertebrae outside instrumentation levels was 18.1 mm (range, 13.5 to 22.1 mm) postindex and 23.3 mm (range, 14.8 to 28.8 mm) in the final follow-up. The average growth was 5.2±3.4 mm in outside instrumentation levels and 7.0±2.9 mm in WIL. These values were significantly different statistically (P<0.01).

CONCLUSIONS

Growing rod treatment performed with regular lengthenings every 6 months appears to stimulate growth in individual vertebral bodies WIL.

LEVEL OF EVIDENCE

Level IV.

In vivo dynamic bone growth modulation is less detrimental but as effective as static growth modulation

Longitudinal bone growth, which occurs in growth plates, has important implications in pediatric orthopedics. Mechanical loads are essential to normal bone growth, but excessive loads can lead to progressive deformities. In order to compare the effects of in vivo static and dynamic loading on bone growth rate and growth plate histomorphometry, a finely controlled, normalized and equivalent compression was applied for a period of two weeks on the seventh caudal vertebra (Cd7) of rats during their pubertal growth spurt. The load was sustained (0.2MPa, 0.0Hz) in the static group and sinusoidally oscillating (0.2MPa±30%, 0.1Hz) in the dynamic group. Control and sham (operated but no load applied) groups were also studied. Cd7 growth rate was statistically reduced by 19% (p<0.001) for both static and dynamic groups when compared to the sham group. Loading effects on growth plate histomorphometry were greater in the static than dynamic groups with significant reductions (p<0.001) observed for growth plate thickness, proliferative chondrocyte number per column and hypertrophic chondrocyte height in the static group when compared to the sham group. Significant differences (p<0.01) were also found between static and dynamic groups for growth plate thickness and proliferative chondrocyte number per column while the difference nearly reached significance (p=0.014) for hypertrophic chondrocyte height. This in vivo study shows that static and dynamic loading are equally effective in modulating bone growth of rat caudal vertebrae. However, dynamic loading causes less detrimental effects on growth plate histomorphometry compared to static loading. This knowledge is greatly relevant for the improvement and/or development of new minimally invasive approaches, which are based on the local modulation of bone growth, to correct several progressive musculoskeletal deformities.

Surgical epiphysiodesis indications and techniques: update

PURPOSE OF REVIEW

To present a summary of epiphysiodesis indications and to report most recent advances in the field, along with their clinical relevance.

RECENT FINDINGS

Percutaneous epiphysiodesis using transphyseal screws (PETS) and guided growth using eight plates represent the most recent techniques used for hemiepiphysiodesis.

SUMMARY

PETS and guided growth have yielded very good results and low rates of complications and are the current standard for the management of angular deformities of the lower extremities in children. Permanent percutaneous epiphysiodesis remains the preferred method for the treatment of limb length discrepancies.

Guided growth

Guiding growth by harnessing the ability of growing bone to undergo plastic deformation is one of the oldest orthopaedic principles. Correction of deformity remains a major part of the workload for paediatric orthopaedic surgeons and recently, along with developments in limb reconstruction and computer-directed frame correction, there has been renewed interest in surgical methods of physeal manipulation or ‘guided growth’. Manipulating natural bone growth to correct a deformity is appealing, as it allows gradual correction by non- or minimally invasive methods.

This paper reviews the techniques employed for guided growth in current orthopaedic practice, including the basic science and recent advances underlying mechanical physeal manipulation of both healthy and pathological physes.