Does eight-plate epiphysiodesis of the proximal tibia in treating angular deformity create intra-articular deformity?

The Effectiveness of Temporary Hemiepiphysiodesis for Non-idiopathic Coronal Angular Deformity of the Knee in Children: A Comparison of Hinge Eight-Plate and Traditional Eight-Plate

OBJECTIVE

Temporary hemiepiphysiodesis (TH) is a very common technique for coronal angular deformity of the knee in children, especially non-idiopathic. However, there is currently a dearth of comparative research on the hinge eight-plate (HEP) and traditional eight-plate (TEP). This study aimed to assess the clinical effectiveness and implant-related complication rates of TH using TEP and HEP for non-idiopathic coronal angular deformity, as well as to identify clinical factors affecting correction velocity.

METHODS

We retrospectively observed a consecutive series of patients with non-idiopathic coronal angular deformity of the knee who underwent TH using HEP or TEP and completed the deformity correction process from July 2016 to July 2022. According to the kind of eight plates, we divided those patients into the HEP group and the TEP treatment group. Relevant clinical factors, including the mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), screw divergence angle (SDA), angle of plate and screw (APS), hinge angle of HEP (HA), and the knee zone location of the lower extremity mechanical axis, were documented. Additionally, deformity correction velocity, complications, and clinical efficacy were assessed. Categorical variables were analyzed using the chi-squared test, Fisher exact test, or Wilcoxon test, while continuous variables were evaluated using the t-test or analysis of variance (ANOVA).

RESULTS

There were 29 patients in the HEP treatment group (seven girls and 22 boys) and 33 patients (12 girls and 21 boys) in the TEP treatment group. In all, 91.86% (79/86 knees) of the genu angular deformities were completely corrected, 6.98% (6/86 knees) had the overcorrection condition, and 10.47% (9/86 knees) had screw loosening. The swayback HEP rate was 11.29% (7/62 HEPs), which was related to the screw loosening in the HEP group (p < 0.001). The overall correction velocities and screw divergence angle change speeds in the HEP group were all significantly faster than those in the TEP group (p < 0.05). The initial APS of the HEP implanted was higher than that of TEP (p < 0.01), and multisite changes of APS during deformity correction of the HEP group were smaller than that of the TEP group.

CONCLUSION

HEP proved to be an appropriate device for TH for non-idiopathic coronal angular deformities of the knee with high correction velocity in children. Avoiding the occurrence of the swayback phenomenon may reduce the complications of HEP.

Limb length deceleration or coronal plane deformity correction using tension band plates: does plate configurations determine the intraarticular deformity of proximal tibia?

We studied whether the two-plate tension band configuration is more prone for intraarticular deformations than the single plate application used for coronal plane deformities (CPD). The study was based on radiological chart review (retrospective cross-sectional) of records of children [15 patients (30 plates) with limb length discrepancies (LLD) and 20 patients (36 plates) with CPD]. Interscrew angle, slope angle, and roof angle were compared in the initial postoperative and final radiographs to determine changes of tibial morphology. The mean patient age and follow up for the LLD and CPD groups respectively were 6.5 years, 39.8 months and 8.1 years, 15.5 months respectively. The interscrew angles widened between initial and final radiographs in the CPD group and for both sides in the LLD group. The initial and final slope angles were not significantly different in both LLD and CPD groups. Similar trend was observed for roof angle in either group. In the intergroup comparisons between LLD and CPD group, the slope angle of medial/lateral operated side in LLD group versus that of the operated side in CPD group matched statistically in the final radiographs. Similarly, the final roof angle in LLD and CPD groups was statistically similar. No significant intraarticular morphological change was demonstrated following tension band plating epiphysiodesis of the proximal tibia for our series involving young children. It was observed neither with the two-plate configuration used for limb length decelerations nor with the single plate application for coronal plane corrections.

Robot-assisted Temporary Hemiepiphysiodesis With Eight-plates for Lower Extremity Deformities in Children

PURPOSE

This study was performed to compare the radiographic results of robot-assisted and traditional methods of treating lower extremity deformities (LEDs).

METHODS

From January 2019 to February 2022, 55 patients with LEDs were treated by temporary hemiepiphysiodesis with eight-plates. They were divided into a robot group and a freehand group. The fluoroscopy time and operation time were recorded. The accuracy of screw placement was measured after the operation using the following parameters: coronal entering point (CEP), sagittal entering point (SEP), and angle between the screw and epiphyseal plate (ASEP). The limb length discrepancy (LLD) and femorotibial angle (FTA) were measured before the operation, after the operation, and at the last follow-up. Patients were followed up for 12 to 24 months, and the radiographic results of the 2 groups were compared.

RESULTS

Among the 55 patients with LEDs, 36 had LLD and 19 had angular deformities. Seventy-six screws were placed in the robot group and 85 in the freehand group. There was no difference in the CEP between the 2 groups ( P >0.05). The robot group had a better SEP (2.96±1.60 vs. 6.47±2.80 mm) and ASEP (3.46°±1.58° vs. 6.92°±3.92°) than the freehand group ( P <0.001). At the last follow-up, there was no difference in the LLD or FTA improvement between the two groups ( P >0.05). The incidence of complications was significantly lower in the robot group than in the freehand group (0/27 vs. 5/28, P <0.05).

CONCLUSION

Robot-assisted temporary hemiepiphysiodesis with eight-plates is a safe and effective method for treating LEDs in children. Robotic placement of screws is superior to freehand placement with respect to the entering position and direction. Although the correction effect for LLD and angular deformity is similar, screw dislocation is less common when using robot assistance.

LEVELS OF EVIDENCE

Level-III. Retrospective comparative study.

Morphology of the knee after guided growth using tension-band devices: a retrospective multicenter study of 222 limbs and 285 implants

BACKGROUND AND PURPOSE

Temporary hemiepiphysiodesis by tension-band devices is commonly applied to correct angular limb deformities in children. We aimed to evaluate knee joint morphology after guided growth using these devices.

PATIENTS AND METHODS

In a retrospective multicenter study we analyzed standardized anteroposterior long-leg radiographs of 222 limbs (285 implants) of patients treated by temporary hemiepiphysiodesis with either eight-Plates or FlexTacks for coronal angular deformities of the knee joint between 2013 and 2019. Femoral floor angle (FFA), femoral notch-intercondylar distance (FNID), and tibial roof angle (TRA) were measured pre- and postoperatively to assess the central knee joint morphology. Statistical exploratory analyses were performed using linear mixed models, t-tests, Wilcoxon signed-rank test, and Mann-Whitney U test.

RESULTS

217 FlexTacks (femur 106, tibia 111) in 104 children and 68 eight-Plates (femur 61, tibia 7) in 35 children were identified. Median time period under growth guidance was 11 months (range 4-42). No statistically significant change in the FFA was detected (eight-Plate: P = 0.2; FlexTack: P = 0.3). A statistically significant difference of the FNID was found in the eight-Plate group (P = 0.02), but not in the FlexTack group (P = 0.3). While TRA increased in both groups, a statistical significance was observed only in the FlexTack group (P < 0.01).

CONCLUSION

We found minor but clinically irrelevant changes in knee morphology after the treatment.

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.

CORONAL PLANE GROWTH MODULATION FOR GENU VALGUM IN SKELETAL DYSPLASIA

Objective

To investigate the efficiency and rates of correction by hemiepiphysiodesis using 8-plate to manage genu valgum deformity in children with skeletal dysplasia.

Methods

Eleven children with skeletal dysplasia (three female, eight male; mean age = 10.5 years; age range = 7-13) who underwent temporary hemiepiphysiodesis using 8-plates for genu valgum deformity were retrospectively reviewed. There were nine bilateral cases and two unilateral cases. The mean follow-up time from the index surgery to the final follow-up was 45 (ranging from 24 to 72) months. Radiographical assessment including preoperative and final follow-up measurements of joint orientation angles and mechanical axis deviation (MAD) were conducted.

Results

Deformities were completely corrected in nine lower extremities (45%) and partially corrected in seven extremities (35%). In four extremities of two children with Morquio syndrome, MAD worsened. The correction rate of MAD was 1.25 ± 1.62 mm/mo.

Conclusion

Though hemiepiphysiodesis using 8-plate requires a longer treatment period, it seems to be an effective treatment for correction of genu valgum in children with skeletal dysplasia. Level of Evidence IV, Case Series.

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.

Lateral Gradual Opening Osteotomy of the Tibia With Monolateral External Fixator for Correcting the Valgus Deformity of the Tibia

The valgus deformity in the tibia requires correction because it places increased pressure on the lateral compartment of the knee, intensifying the degenerative process. Correction strategies are diverse and depend on patient profile, age, and soft-tissue conditions as well as the orthopaedic surgeon's experience with different surgical materials. Deformity size and location are the primary factors contributing to material and shape choice, whether gradual or acute. The only gradual correction approach involves the use of a monolateral or circular external fixator. This is the only indication for correction in cases of excellent deformity, soft-tissue involvement, and a history of bone infection. This study aimed to present a gradual correction technique for tibial valgus deformity using a monolateral external fixator as well as its postoperative follow-up. This technique has the advantages of greater patient acceptance, lighter assembly, and briefer distraction owing to the use of a single piece as well as the ability of the operated limb to bear a load the day after the surgical procedure and dynamic outpatient follow-up.

Controlled rotation of long bones by guided growth: A proof of concept study of a novel plate in cadavers

Our novel plate design has been developed for controlled rotation of long bones by guided growth. The objective of this proof-of-concept study was to evaluate the precision of the rotation in the femur. Twelve cadaverous femora of six adults (right = 6, left = 6) underwent an osteotomy at the level of the physeal scar. The plates were inserted on each side of the distal femur. Growth was simulated by axial distraction of the bone segments. The femur was stabilized using a unilateral external fixator. Femoral torsion was assessed with computed tomography (CT) and with an electric goniometer before and after distraction. The obtained rotation was compared to the predicted rotation based on the dimension of the plate and the bone. All femora were rotated as intended. The mean obtained rotation was 26.3° (95% confidence interval [CI]: 23.5-29.0) and the mean predicted rotation was 28.2° (95% CI: 26.9-29.5) (p > 0.82). The mean axial distraction was 19.5 mm (95% CI: 17.7-21.3). The predicted rotation of the femora was similar to the obtained values on CT and by goniometer. The obtained rotation occurred as a result of an axial distraction of approximately 2 cm. This suggests a potential for controlled rotation of the femur based on the circumference of the bone and plate dimensions that occurs simultaneously with axial distraction. Clinical significance: These findings suggest a possible clinical application in the treatment of maltorsion in children by guided growth, where theplate design guides the bone into torsional axial growth correcting the deformity.

[Epiphysiodesis and hemiepiphysiodesis : Physeal arrest and guided growth for the lower extremity]

The principals of growth arrest by epiphysiodesis and growth guidance by hemiepiphysiodesis are effective and powerful surgical techniques in pediatric orthopedics. These procedures can be used to correct leg length discrepancies as well as sagittal, coronal and oblique deformities. A differentiation is made between temporary and permanent techniques. The most significant advantage is that these techniques are minimally invasive and have low complication rates compared to acute osteotomy and gradual deformity correction. For optimal outcome an exact preoperative planning is needed to ensure accurate timing of the procedure, especially when permanent epiphysiodesis techniques are used. Although epiphysiodesis and hemiepiphysiodesis around the pediatric knee are most frequently used and can be considered the gold standard treatment of coronal plane deformities and leg length discrepancies, novel techniques for the hip and ankle are increasingly being performed. The successful clinical results with low complications support the broad use of hemiepiphysiodesis and epiphysiodesis for a variety of indications in the growing skeleton with deformities and leg length differences.