Advances in growth plate modulation for lower extremity malalignment (knock knees and bow legs)

Gait Analysis in Patients After Hemiepiphysiodesis Due to Valgus or Varus Knee Deformity

Background: Developmental knee joint deformities are a common problem in pediatric orthopedics. Children with a valgus or varus deformity of the distal femur or the proximal tibia are commonly treated with hemiepiphysiodesis. Gait analysis in patients with lower limb deformities plays an important role in clinical practice. The purpose of our study was to assess gait parameters in patients who underwent hemiepiphysiodesis procedures of the distal femur or proximal tibia due to a knee deformity and to compare them with those in healthy controls. Methods: We prospectively evaluated 35 patients (14 females and 21 males) after hemiepiphysiodesis and compared the results with a healthy control group (26 participants). Gait was analyzed with a G-Sensor device (BTS Bioengineering Corp., Quincy, MA, USA). We assessed the following gait parameters: gait cycle duration, step length, support phase duration, swing phase duration, double support duration, single support duration, cadence, velocity, and step length. We assessed these gait parameters in a group of patients before and after treatment with hemiepiphysiodesis. We compared the patients' results before and after treatment to those of a healthy control group. The level of significance was set at p < 0.05. Results: The mean follow-up period was 13 months. There was no difference in the results of gait assessments in patients prior to and after treatment. The median step length was 47.09% in the treated limb after treatment and 54.01% in the intact limb (p = 0.018). There were no other differences in gait parameters in the treated limbs and the healthy, intact limbs in the patient group after treatment. There were no significant differences in the patients before and after treatment compared with those in the healthy control group in all gait parameters. Conclusions: Valgus or varus knee deformity correction with the use of hemiepiphysiodesis does not significantly improve preoperative gait parameters. The biomechanical outcomes of hemiepiphysiodesis in the treatment of valgus or varus knee deformity are good. We observed no differences in gait cycle duration, step length, support phase duration, swing phase duration, double support duration, single support duration, gait velocity, cadence, or step length between the experimental and healthy control groups.

Temporary hemi-epiphysiodesis with tension band plates in skeletally immature patients with genu valgum: Faster correction in patients with more than 2 years of expected time of growth remaining

Purpose

Hemi-epiphysiodesis procedures in skeletally immature patients are commonly done to correct genu valgum over time. This study seeks to demonstrate the average rate of deformity correction for genu valgum using hinged tension band plates, while examining different age groups and sex-related differences.

Methods

A retrospective chart review of patients who underwent hemi-epiphysiodesis with hinged tension band plates for valgus knee deformity from 2012 to 2022 by one pediatric orthopaedic surgeon was performed. Expected time of growth remaining was calculated as the difference between age of skeletal maturity and bone age at time of surgery. The mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, mechanical femoral tibia angle, screw divergence angle, and hinge angle were measured immediately after implant placement and prior to implant removal.

Results

54 skeletally immature patients were treated for pathologic genu valgum. The mean age at time of surgery was 12.5 ± 1.9 years. The radiographic measurement of the valgus deformity between the beginning and end of treatment showed significant correction (p = 0.002). The lower limb axis of the younger cohort corrected significantly faster (7.5 ± 4.6°/year) than the older cohort (5.3 ± 2.8°/year) (p = 0.030). The mechanical lateral distal femoral angle correction rate was also significantly different between the two cohorts (7.0 ± 4.7°/year vs. 4.8 ± 2.8°/year, respectively (p = 0.002)). The group with greater expected time of growth remaining demonstrated a significantly faster rate of correction than the group with less than 2 years of growth remaining (p < 0.001).

Conclusion

This study reaffirms the finding that timing is essential when performing temporary hemi-epiphysiodesis for valgus knee deformity in skeletally immature patients.

Effective time, correction speed and termination time of hemi-epiphysiodesis in children

In children with asymmetric growth on the medial and lateral side of limbs, if there still remains growth potential, the guided growth technique of hemi-epiphysiodesis on one side of the epiphysis is recognized as a safe and effective method. However, when the hemi-epiphysiodesis start to correct the deformities, how many degrees could hemi-epiphysiodesis bring every month and when to remove the hemi-epiphysiodesis implant without rebound phenomenon are still on debate. This article reviews the current studies focus on the effective time, correction speed and termination time of hemi-epiphysiodesis.

The efficacy of hemiepiphysiodesis for idiopathic knee coronal angular deformity by reconstruction plate and screw: A pilot study

Background

Angular deformities of the lower extremities are among the most common findings in pediatric orthopedics. Alteration of the mechanical axis in the lower extremity affects the cosmetic appearance and may lead to gait disturbances, knee discomfort, patellar maltracking with or without pain, and early joint osteoarthritis. In the current study, we aimed to investigate the efficacy of 3-hole 3.5 mm reconstruction plates in tension-band temporary hemiepiphysiodesis for correcting idiopathic knee coronal angular deformities.

Methods

The surgical procedure was performed using an extraperiosteal tension band plate (a 3-hole reconstruction plate) and two 3.5 mm cortical screws to treat idiopathic knee coronal angular deformity in children. The location of the hemiepiphysiodesis was determined based on the type of angular deformity present. Postoperative follow-ups were conducted through x-rays to measure the medial proximal tibial angle and lateral distal femoral angle of the limbs. Statistical analysis was then performed to evaluate the efficacy of the surgical treatment based on the rate of alignment change exhibited.

Results

The study included 14 patients (25 limbs) with genu valgum deformity who underwent temporary hemiepiphysiodesis on both the distal femur and proximal tibia, with 16 proximal tibias and 15 distal femurs being corrected. The correction rate for genu valgum was found to be 0.59° per month for both proximal tibial and distal femoral hemiepiphysiodesis. Six patients (12 limbs) were also identified with genu varum deformity, and the correction rates for proximal tibial lateral hemiepiphysiodesis and distal femoral lateral hemiepiphysiodesis were 0.85° and 0.15° per month, respectively. During a mean follow-up duration of 11 ± 5.7 months, only one case of physeal plate closure was observed, and there were no other significant complications.

Conclusion

Temporary hemiepiphysiodesis with a 3-hole R-plate and two cortical screws takes advantage of physiological physeal growth to successfully treat idiopathic angular deformities with low complication rates.

Use of Implant-Mediated Guided Growth With Tension Band Plate in Skeletally Immature Patients With Knee Pathology: A Retrospective Review

Background: Skeletally immature patients with coronal plane angular deformity (CPAD) may be at increased risk for intra-articular pathology and patellofemoral instability (PFI). These patients may be candidates for implant-mediated guided growth (IMGG) procedures with tension band plates to address CPAD in addition to procedures for concomitant knee pathology. However, there are limited data on performing these procedures simultaneously. Questions/Purpose: We sought to demonstrate the feasibility of combined procedures to address both knee pathology and concomitant CPAD using IMGG in skeletally immature patients. Methods: We conducted a retrospective review of skeletally immature patients who underwent IMGG and concomitant surgery for anterior cruciate ligament reconstruction, osteochondritis dissecans repair, meniscus pathology, or PFI at a single institution by 2 surgeons between 2008 and 2019. Data on demographics, surgical details, follow-up, and complications were recorded. Deformity correction was assessed in a subset of eligible patients. Results: Of 29 patients meeting inclusion criteria, deformity correction was assessed in a subset of 17 patients (15 valgus, 2 varus). At final follow-up, 16 of 17 patients had mechanical tibiofemoral (mTFA) angles of <5° of varus or valgus. One patient developed "rebound" valgus >5° after plate removal. Conclusions: The IMGG performed in the setting of treating intra-articular knee pathology is feasible and should be considered for skeletally immature patients with CPAD undergoing surgery for concomitant knee pathology.

Clinical outcome and correction following V osteotomy for genu valgum in adolescents and young adults: A systematic review

BACKGROUND

Genu Valgum usually originates from distal femur and many open and closed wedge osteotomies of distal femur have been reported but none has proved to be the best. Distal femur V osteotomy is a wedgeless osteotomy and is a rarely reported osteotomy with only a few case series and 167 cases of isolated distal femur V osteotomy for genus valgum in young patients (<25 years) in literature but with a tendency to have an excellent outcomes.

PURPOSE

To determine correction and clinical outcome following V osteotomy for genu valgum in adolescents and young adults (10-25 years).

PATIENT AND METHODS

A systematic research was conducted of PubMed, MEDLINE and Google Scholar to identify studies reporting the correction and clinical outcome following V osteotomy in adolescents and young adults (10-25 years) for genu valgum by 2 different authors according to PRISMA guidelines.

RESULTS

5 studies with 167 patients and 263 knees were identified meeting the inclusion criteria for review. The follow-up period ranged from 3 months to 36 months. Overall complication rate was 12.3%, the most common being plaster sore, 4.2% (11/263) followed by superficial infection, 2.7% (7/263). The mean correction was 19.1° and a mean post-operative valgus was 5.7°. In those compared with Bostman score (157/167), 94.3% had excellent (148/157) and remaining 5.7% (9/157) had good scores (20-27/30) with none showing poor score (<20/30).

CONCLUSION

V osteotomy is a reliable method of distal femoral osteotomy to attain a good correction with an excellent clinical outcome even with variations of fixation however longer follow-up period are required for better evaluation of recurrence.

Angular Deformities of the Knee in Children Treated with Guided Growth

Introduction:

The guided growth technique is an alternative to corrective osteotomy for treating angular deformities of the extremities. It has the advantage of being minimally invasive and is effective in a growing child. This study reports on the outcome of guided growth technique using a plate in correcting knee angular deformities.

Material and Methods:

We conducted a retrospective study of children with angular deformity of the knee treated by the guided growth technique from January 2010 to December 2015 in a tertiary centre. The guided growth technique was done using either the flexible titanium plate (8-plate) or the 2-hole reconstruction plate. Correction of deformity was assessed on radiographs by evaluating the mechanical axis deviation and tibiofemoral angle. The implants were removed once deformity correction was achieved.

Results:

A total of 17 patients (27 knees) were evaluated. Twenty-two knees (81.5%) achieved complete correction of the deformity. The median age was 4.0 (interquartile range 3.0-6.0) years and the median Body Mass Index (BMI) was 26.0 (25.0-28.0). There were 7 unilateral and 10 bilateral deformities with different pathologies (14 tibia vara, 3 genu valgus). The median rate of correction was 0.71° per month. One patient (1 knee) had screw pull-out and two patients (4 knees) had broken screws in the proximal tibia. Three patients (5 knees) failed to achieve complete correction and were subsequently treated with corrective osteotomies. Out of five patients (8 knees) who were followed-up for at least 12 months after removal of hardware, two had rebound deformities. No permanent growth retardation occurred in our patients.

Conclusion:

Our outcome for guided growth to correct knee angular deformity was similar to other studies. Guided growth is safe to perform in children below 12 years old and has good outcome in idiopathic genu valgus and Langeskiold II for tibia vara. Patients should be observed for recurrence until skeletal maturity following implant removal.

Rare PHEX variant with insidious presentation leads to a delayed diagnosis of X-linked hypophosphatemia

A 7-year-old girl without a significant previous medical history was diagnosed with X-linked hypophosphatemic rickets (XLHR) due to a rare, most likely pathogenic, PHEX gene variant after a 4-year delayed diagnosis due to mild clinical presentation. At 2 years of age, her intoeing and femoral bowing were attributed to physiologic bowing and borderline vitamin D sufficiency, despite phosphorus not being measured. Hypophosphatemia was eventually detected after incomplete improvement of bowing and leg length discrepancy with suboptimal linear growth. This rare PHEX variant (c.1949T>C, p.Leu650Pro) further supported the clinical diagnosis of XLHR. Treatment with burosumab (an anti-FGF23 monoclonal antibody) normalised phosphorus and alkaline phosphatase levels and improved her bowing. The diverse phenotypic presentation of this variant can result in delayed diagnosis and highlights the importance of prompt assessment of phosphorus levels in patients with skeletal deformities to ensure timely recognition and treatment.

Correction of coronal plane deformities around knee in children with two-hole tension band plates

Objectives

This study aims to present the 10-year results and complications of two-hole tension band plate hemiepiphysiodesis for coronal deformities around knee in a large population from a single center.

Patients and methods

Seventy-seven patients (46 boys, 31 girls; mean age 93±36 months; range, 22 to 181 months) who underwent temporary hemiepiphysiodesis around knee between January 2009 and January 2019 with two-hole tension band plates were retrospectively evaluated. Improvement of joint orientation angles and mechanical axis deviations, deformity correction rates, etiology groups, and complications were noted.

Results

A total of 166 bone segments (93 femurs, 73 tibias) were included in the study. Mean follow-up duration after the implantation was 36±17 (range, 12 to 88) months. Plates were removed at mean 18±8 (range, 7 to 47) months of implantation. Of the bone segments, 95.2% (n=158) responded successfully to the plates. Mean correction rate of mechanical lateral distal femoral angle in femoral valgum deformity was 0.94±0.43° (range, 0.17 to 2.22)/month and mean correction rate of mechanical medial proximal tibial angle in tibial valgum deformity was 0.62±0.36° (range, 0.11 to 1.55)/month. Mean correction rate of mechanical lateral distal femoral angle in femoral varum deformity was 1.3±0.8° (range, 0.48 to 2.92)/month and mean correction rate of mechanical medial proximal tibial angle in tibial varum deformity was 0.94±0.49° (range, 0.26 to 1.67)/month. The most common complication observed was rebound deformity seen in 41.2% (n=70) of the bone segments. Nine bone segments had persistent hemiepiphysiodesis despite plate removal. Four screw breakages (three metaphysial and one epiphysial) were observed.

Conclusion

Two-hole tension band plate hemiepiphysiodesis appears to be an effective and safe method for the correction of coronal deformities around knee.

Relationship between frontal knee position and the degree of thoracic kyphosis and lumbar lordosis among 10-12-year-old children with normal body weight

INTRODUCTION

Incorrect positioning of the body in space increases the tension of the myofascial tissue and overloads the skeleton. It is important to look for factors that affect the deterioration of body posture that could be eliminated. Understanding the interrelationship between the positioning of individual body segments should be the key knowledge for those involved in the prevention and correction of faulty body posture. The study aimed to determine the relationship between the degree of physiological curvatures of the spine and the incidence of incorrect knee position.

MATERIALS AND METHODS

The study involved 685 children aged 10-12. Body height, weight and BMI were measured and calculated. The degree of thoracic kyphosis and lumbar lordosis was assessed using the Zebris Pointer ultrasound system. Valgus and varus knees were diagnosed in an upright position based on the intermalleolar distance with knees together, and intercondylar distance with the feet placed together. The statistical analysis uses descriptive statistics, the Mann-Whitney U test (comparison of girls and boys), the Kruskal-Wallis test, the Tukey's post hoc test (comparison of variables in participants with correct, varus and valgus knees) and Spearman's rank correlation coefficient (the relationship between the position of the spine and knees).

RESULTS

The examined girls were heavier than the boys and had higher BMI. Spine deformities and incorrect knee position are common among 10-12-year-old children. The girls and boys differed significantly in the spine shape in the sagittal plane and the intermalleolar distance. Round lumbar lordosis is more characteristic for girls, and for boys, round thoracic kyphosis. For both genders, valgus knees occur more often than varus knees and coexist with decreased thoracic kyphosis. The rounder the thoracic kyphosis, the greater distance between the knees and the smaller distance between ankles.

CONCLUSIONS

The frontal knee position significantly correlated with the depth of thoracic kyphosis.

A Growth-Accommodating Implant for Paediatric Applications

Medical implants of fixed size cannot accommodate normal tissue growth in children, and often require eventual replacement or in some cases removal, leading to repeated interventions, increased complication rates and worse outcomes. Implants that can correct anatomic deformities and accommodate tissue growth remain an unmet need. Here, we report the design and use of a growth-accommodating device for paediatric applications that consists of a biodegradable core and a tubular braided sleeve, with inversely related sleeve length and diameter. The biodegradable core constrains the diameter of the sleeve, and gradual core degradation following implantation enables sleeve and overall device elongation in order to accommodate tissue growth. By using mathematical modeling and ex vivo experiments using harvested swine hearts, we demonstrate the predictability and tunability of the behavior of the device for disease- and patient-specific needs. We also used the rat tibia and the piglet heart valve as two models of tissue growth to demonstrate that polymer degradation enables device expansion and growth accommodation in vivo.

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.

Effect of kinesio taping on lower limb joint powers in individuals with genu varum

OBJECTIVE

Therapeutic lateral knee joint muscle taping potentially offers a low-risk, economical and effective alternative for the clinical treatment of light to moderate knee overload, due to misalignment in patients with genu varum. In this study, we aimed at investigating the immediate effect of lateral knee joint muscular kinesio taping on lower limb joint powers, during the stance phase of walking, in individuals with genu varum.

METHODS

Fifteen male subjects with genu varum misalignment (age: 24.2±3.7 years) participated in the study. Subjects performed three walking trials without, and three with, biceps femoris and vastus lateralis kinesio taping. The three-dimensional position coordinate data of reflective markers were collected at 100 Hz using a six-cameras Vicon system (Motion Analysis Corp., UK). Additionally, two Kistler force plates (Kistler AG, Winterthur, Switzerland) were used to record the Ground Reaction Forces (GRF) components at 1000 Hz during stance phase of walking. A three-way ANOVA with post-hoc testing (using paired samples Student's t-test with Bonferroni correction) was performed to compare the power values of lower limb joints before and after the use of KT.

RESULTS

With kinesio taping, we observed that the average negative power increased at the ankle level in dominant limb, (P<0.05, 10-20% of gait cycle, GC), and at the knee level in both limbs (10-20% and 60-80% GC). Further, average negative power of the non-dominant knee joint (80-100% GC) and positive power of the non-dominant hip joint (60-80% GC) significantly reduced (P<0.05) in kinesio taping condition.

CONCLUSION

The biomechanical analysis of joint power during walking using kinesio taping provided essential information about the possible mechanisms involved in gait analysis with this intervention in adults with genu varus.

Radiographic Assessment of Guided Growth: The Correlation Between Screw Divergence and Change in Anatomic Alignment

BACKGROUND

Assessment of changes in anatomic alignment following guided growth traditionally utilizes full-length standing radiographs which subjects patients to larger radiation doses than does a single anteroposterior radiograph of the knee. In an effort to minimize radiation exposure, the present study sought to determine whether changes in screw divergence (SD) of the 2-hole tension band plate used for hemiepiphysiodesis reliably predicts change in alignment.

METHODS

A retrospective review was conducted involving all patients with genu varum or genu valgum treated with hemiepiphysiodesis at a single institution. Preoperative anatomic alignment of the femur, using anatomic lateral distal femoral angle (aLDFA) and anatomic femoral-tibial angle (aTFA), and intraoperative divergence of hemiepiphysiodesis screws were compared with postoperative imaging. Linear regression analysis determined the relationship between changes in SD and changes in alignment, and multivariate regression analysis explored the relationship between the angular changes being measured and various demographic factors.

RESULTS

Linear regression analysis revealed that for every 1 degree change in SD there was a resultant 1.80 degrees of change in aTFA and 2.11 degrees of change in aLDFA. Change in aTFA is predicted by the equation: [INCREMENT]aTFA=0.41×|[INCREMENT]SD|+1.39. The change in aLDFA was predicted by the equation [INCREMENT]aLDFA=0.27×[INCREMENT]SD+1.84 with a R2 of 0.31. [INCREMENT]aTFA and [INCREMENT]SD had a correlation coefficient of 0.68 (95% confidence interval, 0.54-0.78.) [INCREMENT]aLDFA and [INCREMENT]SD had a correlation coefficient of 0.56 (95% confidence interval, 0.42-0.68). [INCREMENT]SD and sex were the only 2 independent predictors for [INCREMENT]aLDFA and [INCREMENT]aTFA as determined by multivariate regression analysis.

CONCLUSION

Change in coronal plane anatomic alignment in patients being treated for genu valgum or genu varum with hemiepiphysiodesis can be reasonably estimated by measuring the change in SD. Therefore, when following patients postoperatively, focal radiographic imaging of the knee can be utilized in lieu of standing full-length limb radiographs to limit radiation to the pelvis in this sensitive patient population.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Does physical therapy prevent post-operative delay in return of function following tension-band plating?

PURPOSE

The clinical outcomes and complications of tension-band plating have been well documented, and commonly include a post-operative delay in return of function. We performed a retrospective comparison study to evaluate the capacity of immediate post-operative physical therapy to prevent this post-operative delay in return of function.

METHODS

Sixty-seven consecutive growth-deformity patients who were treated with tension-band plating at a single institution fulfilled the study criteria. Patients were allocated into two treatment groups: no post-operative physical therapy and immediately post-operative physical therapy. All patients were evaluated for delayed return of function, which was defined as use of crutches, lack of >90° flexion and full extension of the knee, or persistent pain requiring medication at the initial 2-week follow-up visit. Rates of delayed function were compared between the two treatment groups.

RESULTS

Among the study participants, 48 patients had no physical therapy and 19 patients had immediate post-operative physical therapy. Eighteen patients in the no physical therapy group reported a delay (37.5 %) while only 2 patients in the physical therapy treatment group reported a delay (10.5 %); p = 0.0386.

CONCLUSIONS

Delayed return of function dramatically affects pediatric patients, causing unnecessary absence from school and strain on the caregiver. Therefore, it is important to identify treatment modalities to help mitigate the complications of surgery. We conclude that the use of immediate post-operative physical therapy statistically significantly helps patients to return more rapidly to their functional level.

Correction of static axial alignment in children with knee varus or valgus deformities through guided growth: Does it also correct dynamic frontal plane moments during walking?

Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, p<0.001). Contrary to the correlation of the changes, there was no correlation between static and dynamic measures in both sessions. In consequence two patients that had a natural knee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed.

The efficacy and complications of 2-hole 3.5 mm reconstruction plates and 4 mm noncanulated cancellous screws for temporary hemiepiphysiodesis around the knee

BACKGROUND

Persistent angular deformities around the knee can lead to growth-plate damage in childhood and osteoarthritis in adulthood. The treatment options include osteotomy and hemiepiphysiodesis. Tension-band plate hemiepiphysiodesis with 8-plate is an effective way to correct these deformities. However, its high cost makes it less available in many countries. In the present series, we have used 3.5 mm reconstruction plates for tension-band temporary hemiepiphysiodesis.

METHODS

Twenty-one patients with bilateral angular deformities of the knee (42 extremities) underwent temporary hemiepiphysiodesis with 3.5 mm reconstruction plates. The diagnosis, BMI, weight, amount of correction of the deformity age, and device failure were analyzed. The mean follow-up period after plate removal was 17 months (ranging from 8 to 24 mo).

RESULTS

The mean age of the patients was 10 years and 3 months (± 2 y and 10 mo). Complete correction of the deformities was achieved in 86% of patients. Of the 58 plate and screw constructs, 10% had screw breakage. Patients with genu valgum had 2 screw failures (6.25%), but in the genu varum group there were 4 screw failures (40%). Of the 3 patients who did not have complete correction of the deformities, 2 had mucopolysaccharidosis and 1 was nearing skeletal maturity (16 y old). The age of the patient, body weight, BMI, and degrees of angulation did not have any statistically significant correlation with the screw failure. Screw failures in female patients were more common than in male patients. All implant failures occurred in idiopathic patients.

CONCLUSIONS

The efficacy of 3.5 mm reconstruction plates for temporary hemiepiphysiodesis around the knee is similar to that of 8-plates. However, the reconstruction plates have a lower cost and are easily available. Noncanulated 3.5 or 4.5 mm cortical screws seem to be superior to 4 mm noncanulated cancellous screws.

LEVEL OF EVIDENCE

Level 3.

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.

Growth guidance of angular lower limb deformities using a one-third two-hole tubular plate

PURPOSE

The eight-plate system for angular deformity correction is well known, reliable and effective at any age during growth. Due to high implant costs, we sought to evaluate the effectiveness and safety of a less expensive alternative.

METHODS

Between 2006 and 2011, 41 children with angular deformities were managed using a two-hole one-third tubular plate in cases where an eight plate would normally be indicated. Inclusion criteria in this retrospective study were: genu valgum and genu varum. X-ray documentation was performed before and after surgery and patients were followed clinically every 3 months after surgery. The cost per implant was 361.40 Sfr (Swiss Francs) compared to the eight plate at 737 Sfr.

RESULTS

Mean time for correction was 13 months. A mean LDFA/MPTA after correction of 89.9°/86.8° was recorded, as well as a mean correction angle of 6.8°/6.6°. The complication rate was 6.6 % (one superficial wound infection and one insufficient correction in an older child). These results compare favourably with published data on the eight plate.

CONCLUSION

The two hole one-third tubular plate seems to be a clinically and also cost effective alternative to the eight plate. Full deformity correction is gained for a fraction of the cost.

LEVEL OF EVIDENCE

Level III.

Guided growth by a stainless-steel tubular plate

Guided growth using titanium tension band plates is an advancement in the correction of angular deformity. We applied two-hole stainless-steel one-third tubular plates for the same purpose. There were 14 deformities around the knees in eight children, mean age 10.8 years at operation. The success rate was 92.9% (13/14). The average correction rate per month was 0.59° in the femur and 0.65° in the tibia. No premature physeal arrest, overcorrection, or rebound phenomenon was observed. A stainless-steel plate is a safe and effective option for guided growth surgery in countries where only stainless-steel plates are available.

Gradual bilateral genu varum correction in skeletal dysplasia using the Ilizarov method

BACKGROUND

Options for lower limb realignment in skeletal dysplasia are acute versus gradual correction, internal versus external fixation, and external fixation with or without intramedullary nailing. The safety and versatility of the Ilizarov method in skeletal dysplasia patients makes it a procedure of choice.

MATERIALS AND METHODS

We describe here our experience with this procedure with 48 skeletal dysplasia patients, with a mean age of 15 years, and a minimum follow-up of 2 years. Preoperative, postoperative, and latest follow-up measurements of tibia-femur (T-F) angle, conventional mechanical axis deviation (MAD-C), ground mechanical axis deviation (MAD-G), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior distal femoral angle (PDFA), and posterior proximal tibial angle (PPTA) were compared.

RESULTS

The mean lengthening amount (LA) was 7.4 cm, mean lengthening percentage (LP) was 35.5%, mean external fixation index (EFI) was 28 days/cm, and mean healing index (HI) was 35 days/cm. Mean MAD-C and MAD-G correction were 9.3 mm and 11.8 mm, respectively. T-F angles, PPTA, MAD-C, and MAD-G were significantly improved. Equinus deformity was the most prominent obstacle, and varus recurrence was the most frequent sequela.

CONCLUSION

In most skeletal dysplasia patients, lower limb realignment with gradual deformity correction using the Ilizarov method may be a reliable option. Equinus deformity occurs in those with more than 40% lengthening, but can be easily corrected. In addressing varus recurrence after gradual correction, the intrinsic and extrinsic factors should be sought first then treated accordingly.

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.