Hemiepiphysiodesis: similar treatment time for tension-band plating and for stapling: a randomized clinical trial on guided growth for idiopathic genu valgum

An International Consensus on Evaluation and Management of Idiopathic Genu Valgum: A Modified Delphi Survey

BACKGROUND

Idiopathic genu valgum beyond physiological limits may require treatment, which is based on age, growth remaining, and the magnitude of the deformity. There is no consensus on clinical, or radiologic evaluation, indications, and management of idiopathic genu valgum, which can range from observation to surgical treatment using various modalities. If available, such guidelines will help surgeons offer optimal treatment to their patients. The aim of our study was to establish an expert consensus on the evaluation and treatment of idiopathic genu valgum.

METHODS

An international panel of 29 pediatric orthopaedic surgeons from 17 countries with clinical and research experience in the management of limb deformity participated in a modified Delphi survey. Surgeons were provided with patient and deformity characteristics and voted on 46 statements on history, clinical examination, radiographic evaluation, and treatment options for idiopathic genu valgum in round 1. Consensus was defined as when statements received ≥70% votes. Statements that were important but received <70% votes were reworded for clarity in round 2 (n=13).

RESULTS

Consensus was achieved for 28/46 statements and included obtaining a full-length standing radiograph of the lower extremities and measuring joint orientation angles. Participants did not agree to offer surgical treatment based only on the intermalleolar distance. They recommended surgical treatment if the mechanical axis falls in zone 2 or beyond on the lateral side and using guided growth by tension-band plating when the growth remaining is at least 2 years. The panel agreed on performing common peroneal nerve decompression for specific indications such as acute, opening wedge osteotomy of >20 degrees, but not for gradual correction. Consensus was not reached for indications and methods of bone age assessment, treatment when growth remaining is <1 year, indications for implant removal after guided growth in younger children, and the type of osteotomy for acute deformity correction.

CONCLUSIONS

We have generated consensus statements to guide the management of idiopathic genu valgum. Statements that lack consensus are areas for future multicenter research.

LEVEL OF EVIDENCE

Level V.

Follow-Up After Hemiepiphysiodesis: Can We Do Better?

BACKGROUND

Hemiepiphysiodesis carries a risk of overcorrection, especially if the patient demonstrates poor follow-up. Few studies have evaluated patients treated with hemiepiphysiodesis for risk factors predictive of follow-up. The present study evaluates patients who underwent hemiepiphysiodesis at the knee and/or ankle for associations between late follow-up (LFU), lost to follow-up (LTFU), and sociodemographic factors, such as area deprivation index (ADI), race, ethnicity, insurance status, age, sex, and BMI.

METHODS

Skeletally immature patients undergoing hemiepiphysiodesis from 2018 to 2022 for coronal deformities of the knee and ankle were retrospectively studied through electronic medical record. Follow-up status was categorized as on-time follow-up (OTFU), LFU, or LTFU. Late presentation was defined as presentation over 6 months past the recommended follow-up date. The angle between the mechanical axis of the femur and the tibia and the lateral distal tibial angle were measured preoperatively and at final follow-up for coronal knee deformities and ankle valgus, respectively. Overcorrection was stratified by severity: 0° to 5° was considered acceptable, 5° to 10° mild, 10° to 15° moderate, and >15° severe. OTFU was used as a reference for statistical comparisons of follow-up status. Statistical comparisons were performed with multivariate analysis.

RESULTS

One hundred fifty-five patients were included, 91 male and 64 female. In all, 103 patients followed up on-time, 28 were LFU (mean 17.9 mo after recommended follow-up), and 24 (average 6.5 mo from surgery) were LTFU. Of the LFU, 4 underwent an additional procedure to correct new deformity. Of the LFU genu valgum limbs, 50.0% were severely overcorrected. Of the LFU genu varum limbs, 38.5% were severely overcorrected. ADI (national), male, black race, and uninsured status were significantly more likely to be LTFU. The predominant deformity in both the LFU and LTFU groups was genu varum and the predominant diagnosis was Blount disease.

CONCLUSION

Poor follow-up after hemiepiphysiodesis can result in overcorrection necessitating additional procedures. Factors associated with LFU included a diagnosis of genu varum. Factors associated with LTFU included older age, high national ADI, increased weight for age percentile, male, black race, uninsured status, and genu varum. Quality improvement measures should be implemented to ensure follow-up in high-risk groups.

LEVEL OF EVIDENCE

Level IV.

Factors Affecting Postoperative Courses After Removal of Transphyseal Screws Inserted for Correction of Genu Valgum

BACKGROUND

The aim of this study was to investigate factors determining the final outcomes of hemipercutaneous epiphysiodesis using transphyseal screw (PETS) for the genu valgum, especially focusing on postoperative courses after screw removal.

METHODS

Fifty-five patients with idiopathic genu valgum treated with hemi-PETS were included. The mechanical lateral distal femoral angle (mLDFA) and medial proximal tibial angle (MPTA) were measured to calculate the degree of correction and rebound. Regarding factors related to surgical techniques, the number of screw threads beyond the physis, the moment arm of the screw, and screw insertion angles were measured.

RESULTS

In 54 femoral segments (randomly selected in bilateral cases), hemi-PETS was performed with a growth remaining of 2.0±0.6 years. The screw was removed after 6.5±2.1 months, and the degree of correction was 5.0±1.5 degrees. The mean rebound angle was -0.4±2.4 (the negative value means further correction after screw removal). A late time of surgery and an extreme peripheral position of a screw were associated with the growth inhibition. In 50 tibial segments (also randomly selected in bilateral cases), a screw was inserted with a growth remaining of 2.0±0.6 years and removed after 6.3±1.9 months. The degree of correction was 2.9±1.7 degrees during the interval, and the rebound angle was 0.8±1.7 degrees. An earlier time of surgery and a greater correction angle before screw removal were associated with the rebound phenomenon.

CONCLUSIONS

Growth inhibition of >1.6 degrees was observed in about one-fourth of femoral segments. An extreme peripheral position of a screw should be avoided when performing hemi-PETS at the distal femur. We also recommend not performing hemi-PETS at distal femur with too short a period of growth remaining.

LEVEL OF EVIDENCE

Level III-retrospective comparative series.

Guided growth: angular deformity correction through temporary hemiepiphysiodesis with a novel flexible staple (FlexTack)

Temporary hemiepiphysiodesis (HED) is applied to children and adolescents to correct angular deformities (ADs) in long bones through guided growth. Traditional Blount staples or two-hole plates are mainly used for this indication. Despite precise surgical techniques and attentive postoperative follow-up, implant-associated complications are frequently described. To address these pitfalls, a flexible staple was developed to combine the advantages of the established implants. This study provides the first results of guided growth using the new implant and compares these with the established two-hole plates and Blount staples. Between January 2013 and December 2016, 138 patients (22 children, 116 adolescents) with genu valgum or genu varum were treated with 285 flexible staples. The minimum follow-up was 24 months. These results were compared with 98 patients treated with 205 two-hole plates and 92 patients treated with 535 Blount staples. In long-standing anteroposterior radiographs, mechanical axis deviations (MADs) were measured before and during treatment to analyze treatment efficiency. The evaluation of the new flexible staple was performed according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework (Stage 2a). Overall, 79% (109/138) of patients treated with flexible staples achieved sufficient deformity correction. The median treatment duration was 16 months (interquartile range (IQR) 8 to 21). The flexible staples achieved a median MAD correction of 1.2 mm/month/HED site (IQR 0.6 to 2.0) in valgus deformities and 0.6 mm/month/HED site (IQR 0.2 to 1.5) in varus deformities. Wound infections occurred in 1%, haematomas and joint effusions in 4%, and implant-associated complications in 1% of patients treated with flexible staples. Valgus AD were corrected faster using flexible staples than two-hole plates and Blount staples. Furthermore, the median MAD after treatment was lower in varus and valgus AD, fewer implant-associated complications were detected, and reduced implantation times were recorded using flexible staples. The flexible staple seems to be a viable option for guided growth, showing comparable or possibly better results regarding correction speed and reducing implant-associated complications. Further comparative studies are required to substantiate these findings.

Indications and timing in isolated medial femoral hemiepiphysiodesis for idiopathic genu valgum: A systematic review

INTRODUCTION

Temporary isolated medial femoral hemiepiphysiodesis (TIMFH) represents a safe and effective technique widely used to treat idiopathic genu valgum. Recent studies mainly concentrated on comparing outcomes of different implants, while less attention has been reserved to the proper indications and timing for surgery. The aim of this systematic review was to provide evidence-based guidelines about indications for device implant and removal and postoperative management.

METHODS

A comprehensive literature search was performed across three databases to select articles concerning TIMFH in the treatment of idiopathic genu valgum. Studies involving other etiologies or concomitant surgical procedures were excluded. Quality assessment of the included studies was conducted through the Newcastle-Ottawa Scale.

RESULTS

Ten studies involving 237 patients for a total of 446 knees were included in the analysis. Mean age at surgery was 11,4 years. Patients were considered for surgery using various clinical and radiological parameters. Intermalleolar distance (IMD) and mechanical lateral distal femoral angle (mLDFA) were the most common evaluated. Mean treatment time was 12 months. Rebound of the deformity occurred in 6,7% of cases.

CONCLUSION

Results of this review showed good consensus among authors. Patients undergoing TIMFH for IGV should be minimum 8 years old, with an IMD greater than 8 cm and a mLDFA lower than 87°. Postoperative management should comprise of quarterly clinic evaluations, and follow-up should last until skeletal maturity. The application of more uniform parameters in clinical practice may improve the establishment of the optimal timing for implant removal.

Surgical Outcome of Complex Knee Deformity Correction in a Girl With Ellis-van Creveld Syndrome: A Report of a Rare Case

Ellis-van Creveld (EVC) syndrome is a rare inherited condition with inheritance, which is autosomal recessive in nature and is also described as skeletal dysplasia (chondroectodermal). The patients present with a grave genu valgum deformity which is a major challenge in orthopedics. The current case report presents a young girl of the juvenile age group who came with deformity over the bilateral lower limb with difficulty in walking and bilateral upper limb polydactyly. The patient underwent relevant investigations and examinations which were suggestive of bilateral genu valgum deformity. Since the deformity was significant, a corrective osteotomy with soft tissue release was planned followed by rehabilitative physiotherapy. Considering the extensive nature of the surgery, a staged procedure was planned. The patient on follow-up presented with a good range of motion and improved gait. Various treatment modalities have been described for the correction of the deformity but few of them are done in patients with EVC syndrome and they state varying results and high incidences of relapse. The present study focuses on corrective osteotomy with soft tissue release as a treatment modality and describes the outcome associated with the modality. Thus, stating that with proper planning and postoperative rehabilitation the patient can achieve a good functional outcome.

Natural behaviours after guided growth for idiopathic genu valgum correction: comparison between percutaneous transphyseal screw and tension-band plate

BACKGROUND

Percutaneous epiphysiodesis using a transphyseal screw (PETS) or tension-band plating (TBP) has shown favourable correction results; however, the physeal behaviours in terms of rebound, stable correction, or overcorrection after guided growth have not been completely understood. In patients with idiopathic genu valgum, we therefore asked: (1) How is the correction maintained after implant removal of guided growth? (2) Is there any difference in the natural behaviours after PETS or TBP removal at the femur and tibia?

METHODS

We retrospectively reviewed 73 skeletally immature limbs with idiopathic genu valgum treated with PETS or TBP. PETS was performed in 23 distal femurs and 13 proximal tibias, and TBP was performed in 27 distal femurs and ten proximal tibias. Mechanical axis deviation (MAD), mechanical lateral distal femoral angle (mLDFA), and mechanical medial proximal tibial angle were measured at pre-correction, implant removal, and final follow-up. Changes of ≤ 3° in mechanical angles after implant removal were considered stable. Comparisons between the implant, anatomical site, and existence of rebound were performed.

RESULTS

The mean MAD improved from - 18.8 mm to 11.3 mm at implant removal and decreased to -0.2 mm at the final follow-up. At the final follow-up, 39 limbs (53.4%) remained stable and only 12 (16.4%) were overcorrected. However, 22 limbs (30.1%) showed rebound. TBP was more common, and the correction period was longer in the rebound group (p < 0.001 and 0.013, respectively). In femurs treated with PETS, the mean mLDFA increased from 86.9° at implant removal to 88.4° at the final follow-up (p = 0.031), demonstrating overcorrection. However, a significant rebound from 89.7° to 87.1° was noted at the femur in the TBP group (p < 0.001). The correction of the proximal tibia did not change after implant removal.

CONCLUSION

The rebound was more common than overcorrection after guided growth; however, approximately half the cases demonstrated stable correction. The overcorrection occurred after PETS in the distal femur, while cases with TBP had a higher probability of rebound. The proximal tibia was stable after implant removal. The subsequent physeal behaviours after each implant removal should be considered in the guided growth.

Factors Affecting Rebound Phenomenon After Temporary Hemiepiphysiodesis and Implant Removal for Idiopathic Genu Valgum in Adolescent Patients

BACKGROUND

The aim of this study was to investigate factors determining postoperative courses, especially focusing on the rebound phenomenon, in adolescent patients with idiopathic genu valgum who underwent temporary hemiepiphysiodesis and implant removal.

METHODS

We identified and reviewed patients with idiopathic genu valgum treated with temporary hemiepiphysiodesis [using tension-band plates (plate group, PG) or transphyseal screws (screw group, SG)] and followed-up to skeletal maturity.

RESULTS

In our cohort [68 patients and their 68 limbs (randomly selected in bilateral cases)], the mean hip-knee-ankle alignment was -5.4±1.8 degrees at the time of temporary hemiepiphysiodesis (negative means valgus), 2.6±2.1 degrees at the time of implant removal, and 0.7±2.6 degrees at the last follow-up, respectively. Regarding the implants, the correction speed was not significantly different (P=0.192-0.315) between the PG (total 1.29±0.37 degrees/mo, 0.71±0.23 degrees/mo at distal femur, 0.59±0.16 degrees/mo at proximal tibia, n=19) and the SG (total 1.22±0.49 degrees/mo, 0.65±0.25 degrees/mo at distal femur, 0.57±0.23 degrees/mo at proximal tibia, n=49). The magnitude of rebound phenomenon in the PG (4.1±1.9 degrees) was greater (P<0.001) than that in the SG (1.1±3.1 degrees). The use of plates and faster correction speed, rather than more severe preoperative deformity or greater correction angle, were positively associated with the rebound phenomenon in regression analyses. Among the 68 knees, 1 showed valgus alignment ≥5 degrees and 5 showed varus alignment ≥5 degrees at the last follow-up. All the 6 cases were observed in the SG. Surgical wound dehiscence was observed in 1 patient in the PG.

CONCLUSIONS

The use of plates and faster correction speed were positively associated with the rebound phenomenon. Careful attention will be needed with the corresponding conditions for optimal results. Progressive genu varum after transphyseal screw removal, which was observed in this study, should be explored in future research.

LEVEL OF EVIDENCE

Level III-retrospective comparative series.

Hemiepiphysiodesis for coronal angular knee deformities: tension-band plate versus percutaneous transphyseal screw

INTRODUCTION

Pediatric coronal plane knee deformities can be treated surgically using hemiepiphysiodesis. The two leading techniques used for hemiepiphysiodesis are: tension-band plates (TBP) and percutaneous transphyseal screws (PETS). We hypothesized that PETS would lead to faster guided correction of angular knee deformities than TBP.

MATERIALS AND METHODS

A retrospective cohort of 35 patients treated with either TBP or PETS in one medical institution was established. The cohort included both genu varum and genu valgum of both primary and secondary etiologies. We first compared the treatment groups for differences in demographic and malalignment characteristics. Then, we compared the treatment groups for differences in operation-related outcomes, radiological mechanical correction and complication rates.

RESULTS

We found that the use of PETS, compared to TBP, was associated with a faster implantation surgery and a shorter interval between implantation and removal, i.e., faster correction. Furthermore, PETS were associated with faster correction rates of the mechanical axis deviation, lateral distal femoral angle and medial proximal tibial angle. No significant differences in complication rates were found between the two treatments.

CONCLUSION

PETS provided a faster correction of angular knee deformities compared to TBP at similar complication rates. Hence, PETS could be considered a superior technique for hemiepiphysiodesis.

Efficacy of Percutaneous Retrograde Transphyseal Guided Growth Screw in Distal Femoral Angular Deformity Correction: A New Technique

BACKGROUND

We modified the original technique for percutaneous transphyseal screw which was described in 1998 by Metaizeau and colleagues for distal femoral coronal angular deformity correction; the modification is related to the screw direction, whereas the screw is administered in a retrograde pattern, starting from the epiphysis and directed toward the metaphysis. This technique opposes the original technique that was started with a metaphyseal entry point which aimed toward the epiphysis. This study evaluates the efficacy of the newly suggested surgical technique regarding the rate of correction and growth resumption after screw removal.

METHODS

This prospective study looked at 40 patients (65 distal femoral physes), who underwent a percutaneous retrograde transphyseal guided growth screw procedure, from October 2017 to September 2019. All the patients included had distal femoral coronal angular deformities; 52 in valgus and 13 in varus deformities. The study included 17 females with an average age of 11.75 (range: 8.4 to 14.5 y) for 29 femurs and 23 males with an average age of 13.75 (range: 11.75 to 15.6 y) for 36 femurs. The mechanical lateral distal femoral angle was measured initially, and then again was measured after reaching the desired corrected orientation. The patients were then followed up after the screw removal and followed up to maturity, if the physis had continued to grow postcorrection. The degree of correction per month was calculated, and the consequence of screw removal was detected. Follow-up average time was 12.6 months (range: 30 to 6 mo).

RESULTS

The average correction in the distal femur was 1.3 degrees per month (range: 0.5 to 1.857 degrees/mo). In all of the 65 segments (61 femurs had significant growth remaining and 4 femurs had reached skeletal maturity with suboptimal mechanical lateral distal femoral angle correction), the screws were removed at the time of angular correction. Rebound growth was observed in 15 physes with an average of 1.8 degrees (range: 2 to 3 degrees); they were stable in 42 physes and progressed in 4 physes with an average of 1.6 degrees (range: 1 to 2 degrees). Complications were minor and related to entrapment of soft tissue under the screw washer.

CONCLUSION

Percutaneous retrograde transphyseal guided growth screw for distal femur coronal angular deformity is a minimally invasive procedure, with a statistically significant correction rate when compared with the original transphyseal screw technique. The new technique has proven to have growth resumption after screw removal with minimal complication risk.

LEVEL OF EVIDENCE

Level III-prospective observational study.

Evaluation of spin in the abstracts of orthopedic trauma literature: A cross-sectional review

OBJECTIVES

A cross-sectional analysis of orthopedic trauma randomized controlled trial (RCT) abstracts to assess the frequency and manifestations of spin, the misrepresentation or distortion of research findings, in orthopedic trauma clinical trials.

METHODS

The top 5 orthopedic trauma journals were searched from January 1, 2012, to December 31, 2017. RCTs with nonsignificant endpoints (p > .05) were analyzed for spin in the abstract. The primary endpoint of our investigation was the frequency and type of spin. The secondary endpoint was to assess whether funding source was associated with the presence of spin. Due to the low reporting of funding sources no statistics were able to be computed for this outcome.

RESULTS

Our PubMed search yielded 517 articles. Primary screening excluded 303 articles, and full text evaluation excluded an additional 161. Overall, 53 articles were included. Spin was identified in 35 of the 53 (66.0%) abstracts analyzed. Evidence of spin was found in 21 (39.6%) abstract results sections and 22 (41.5%) abstract conclusion sections. Of the 21 RCTs reporting a clinical trial registry, 3 (14.3%) had evidence of selective reporting bias.

CONCLUSIONS

Orthopedic trauma RCTs from highly ranked journals with nonsignificant endpoints published from 2012 to 2017 frequently have spin in their abstracts. Abstracts with evidence of spin may influence a reader's perception of new drugs or procedures. In orthopedic trauma, the implications of spin may affect the treatment of patients with orthopedic trauma, so efforts to mitigate spin in RCT abstracts must be prioritized.

Growth modulation of angular deformities with a novel constant force implant concept-preclinical results

PURPOSE

Varus-valgus deformities in children and adolescents are often corrected by temporary hemi-epiphysiodesis, in which the physis is bridged by an implant to inhibit growth. With standard implant solutions, the acting forces cannot be regulated, rendering the correction difficult to control. Furthermore, the implant load steadily increases with ongoing growth potentially leading to implant-related failures. A novel implant concept was developed applying a controlled constant force to the physis, which carries the potential to avoid these complications. The study aim was to proof the concept in vivo by analyzing the effect of three distinct force levels on the creation of varus deformities.

METHODS

The proposed implant is made of a conventional cerclage wire and features a twisted coil that unwinds with growth resulting in an implant-specific constant force level. The proximal medial tibial physes of 18 lambs were treated with the implant and assigned to three groups distinct by the force level of the implant (200 N, 120 N, 60 N).

RESULTS

The treatment appeared safe without implant-related failures. Deformity creation was statistically different between the groups and yielded on average 10.6° (200 N), 4.8° (120 N) and 0.4° (60 N) over the treatment period. Modulation rates were 0.51°/mm (200 N), 0.23°/mm (120 N) and 0.05°/mm (60 N) and were constant throughout the treatment.

CONCLUSION

By means of the constant force concept, controlled growth modulation appeared feasible in this preclinical experiment. However, clinical trials are necessary to confirm whether the results are translatable to the human pathological situation.

Growth modulation for fixed flexion contracture of the knee: a comparison of two techniques

Growth modulation has become a mainstream treatment for frontal plane angular lower extremity deformities in children. Few articles address the effect of growth modulation on sagittal deformity. Our aim is to compare two anterior distal femoral growth modulation techniques for fixed knee flexion contracture. Electronic medical records were reviewed for patients who underwent anterior femoral growth modulation for fixed flexion contracture. Patients were excluded if adequate preoperative/postoperative radiographs were unavailable. A cohort was subdivided based on surgical technique: screws alone versus dual tension-band plates. Complications were recorded; radiographs were evaluated preoperatively and at hardware removal. Posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA), and anterior cortical line (ACL) angle were evaluated. Of 35 patients identified, 20 patients (29 knees) were included. Thirteen knees were treated with dual anterior tension-band plates; 16 knees had transphyseal screws. Sagittal alignment improved in both groups. Statistically significant PDFA changes were observed in the tension-band plate group (P = 0.0095); a trend was noted toward improvement in ACL angle (P = 0.08). PPTA did not change. No changes reached significance in the transphyseal screw group (PDFA: P = 0.181, ACL: P = 0.64). Tension-band plate migration was noted in one (7.7%) of 13 knees, and transphyseal screw migration in nine (56.3%) of 16 knees (P < 0.01). Anterior distal femoral growth modulation improves sagittal alignment without significant remodeling at the proximal tibia. Hardware migration occurred more often with transphyseal screws (P < 0.01). We recommend dual anterior tension-band plating over placement of paired screws for sagittal growth modulation to treat knee flexion contracture.

Correction of the knee coronal plane deformity using the screws plus reconstruction plate versus cannulated screws

INTRODUCTION

Knee angular deformity is a common finding occurring in the childhood that can cause gait disturbances and early compartment osteoarthritis. Despite various surgical approaches presented to correct the angular deformities of the knee, there is still a search for the best approach. Thus, the present study was conducted to compare the results of using cannulated screw (CS) versus screw plus reconstruction plate (SpRP) for correction of angular deformities through a two-year follow-up study.

HYPOTHESIS

Percutaneous CS implantation is as efficacious as SpRP implantation for the correction of angular deformities of the knee.

MATERIAL AND METHODS

This randomised clinical trial (RCT) was conducted on 63 patients with angular deformities who were randomly divided into two groups including treatment with cannulated screw (CS) (n=32) and treatment with screw plus reconstruction plate (SpRP) (n=31). All the patients underwent the alignment view radiography of both lower limbs before surgical procedure and then within 3, 6, 12, 18 months and 2 years following the surgery. Afterwards, the patients' mechanical axis of the knees, medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), and varus/valgus angles were assessed and compared.

RESULTS

Results of the study showed that MPTA and LDFA significantly turned to the normal range during the 18 months follow-up in both treatment groups (p-value<0.001). Varus and valgus angles were corrected in both techniques as well postoperatively (p-value<0.001). Ultimate correction was achieved earlier in the CS treated group (12 months versus 18 months later).

DISCUSSION

Findings of the study revealed that the percutaneous CS implantation was successful similar to the SpRP implantation for correction of the angular deformity, while earlier ultimate angular correction and less pain complaint were among the superiorities of the CS.

LEVEL OF THE STUDY

II, comparative prospective study.

Mechanobiological based long bone growth model for the design of limb deformities correction devices

A mechanobiological model of bone growth aimed for the design of medical devices for the treatment of limb deformities during childhood and adolescence was developed. Dimensional analysis was introduced as a tool for the systematic evaluation of the influence attributed to different factors that might modify the bone growth process. Simplifications were proposed, allowing the reduction of bone growth relevant parameters to four non-dimensional numbers, representing the chondrocyte sensitivity to stress, the epiphyseal plate geometry, the bone rigidity and the time. Benchmark situations considered for model validation were bone growth under normal conditions and an epiphyseal stapling treatment. A finite elements approach was used to analyze bone growth in the distal portion of the femur. Results are shown to be consistent with corresponding clinical data published in the literature, which indicates the potential of the here proposed method for the design of specific devices and treatments.

HEMIEPIPHYSIODESIS USING EIGHT-PLATE VERSUS BLOUNT STAPLE TO CORRECT GENU VALGUM AND GENU VARUM

Objective:

Our objective is to evaluate whether the use of guided growth with eight-plates is more effective than the use of Blount staples for the correction of the idiopathic genu varum or idiopathic genu valgum.

Methods:

A systematic review (SR) was carried out according to the appropriate methodology for randomized clinical trials (RCTs). We searched seven databases through a previously defined methodology, and we included RCTs, regardless of language, period of publication and status of publication.

Results:

Resulted in 6830 articles retrieved. Of theses, we identified 14 potential eligible studies. but just one RCT was included for the SR. The included RCT compares the eight-plate and the Blount staple and showed no statistically significant difference for the outcomes of time to correct the deformity, postoperative pain after 24 hours and postoperative pain after 72 hours. The study is of low or very low level of evidence to determine the most effective technique. We didn’t find a RCT that compared the correction of the genu varum.

Conclusion:

Good quality randomized clinical trials comparing Blount staples versus eight-plaque must be performed to determine which technique is superior for coronal plane corrections. Level of Evidence I, Systematic review of Level RCTs.

Growth Modulation for Knee Coronal Plane Deformities in Children With Nutritional Rickets: A Prospective Series With Treatment Algorithm

To report prospectively the radioclinical outcome of guided growth surgery for coronal plane deformities around the knee in young children with nutritional rickets on the intermediate term, to assess the responsiveness of torsional deformities of the tibias to guided growth regarding function and objective clinical parameters, and to propose a treatment algorithm.

Hemiepiphysiodesis for Idiopathic Genu Valgum Using Physeal Staples Versus Tension-Band Plating: A Systematic Review

This review assesses the outcomes of hemiepiphysiodesis in patients with idiopathic genu valgum (IGV) treated with physeal staples vs tension-band plating (TBP). A systematic review of the literature was conducted to identify articles examining the use of physeal staples vs TBP for the treatment of IGV in skeletally immature patients. No significant difference in overall mean deformity correction (P=.92) or correction per month (P=.61) was observed between groups. Repeat hemiepiphysiodesis was more common in patients who underwent TBP vs physeal staples (P=.05). Tension-band plating did not yield significantly improved results compared with physeal staples in skeletally immature patients with IGV. [Orthopedics. 2019; 42(6):e485-e491.].

Hemiepiphysiodesis using tension band plates: does the initial screw angle influence the rate of correction?

PURPOSE

When using tension band plates for angular deformity correction, the literature is unclear regarding the most effective screw insertion angle to use. This study evaluates the correlation between initial screw angle and the average rate of correction during hemiepiphysiodesis using tension band plates.

METHODS

This retrospective study includes 35 patients (47 physes) with genu valgum deformity (17 idiopathic and 18 fibular hemimelia) who underwent insertion of Eight-Plates between 2010 and 2015. Initial screw angle was determined from the intraoperative fluoroscopic images. Radiographs were obtained within three months of surgery, and follow-up films were obtained every three to six months. Change in mechanical lateral distal femoral angle, medial proximal tibial angle and screw angle was obtained from each follow-up radiograph. Initial screw angle was correlated with the average rate of correction during the entire treatment period. The average rate of angular correction during first and last follow-up periods was also compared.

RESULTS

The relationship between the initial screw angle and the mean rate of angular correction was not statistically significant (p = 0.2). The rate of angular correction during the first follow-up period (mean of 4.7 months) was 0.86° per month compared with 0.71° per month during the last follow-up period (mean of 5.1 months).

CONCLUSION

Application of a tension band plate with a divergence angle ranging from 0° to 30° results in similar rates of angular correction. For surgeons inserting screw-plate tension band devices, there does not seem to be any necessity to make the screws parallel or divergent. We recommend that screw placement be anatomically correct, i.e. not impinging on the physis, rather than favouring any particular divergence angle.

LEVEL OF EVIDENCE

IV.

Radiographic Results and Complications of 3 Guided Growth Implants

BACKGROUND

Temporary, implant-mediated hemiepiphysiodesis (ie, guided growth) is an effective and popular treatment method for lower extremity angular deformities. The purpose of this study was to retrospectively evaluate the safety profile of 3 different implants used to correct lower extremity angular deformities in pediatric patients.

METHODS

We retrospectively reviewed a consecutive series of pediatric patients with lower extremity angular deformities who underwent implant-mediated guided growth by 2 surgeons at our institution between 2004 and 2014. Implants were selected according to surgeon preference and included the Biomet peanut plate, Orthofix eight-plate, and Pega Medical hinge plate. Medical records and radiographs were reviewed to assess deformity correction, implant integrity, and complications.

RESULTS

During the study period, 115 plates (63 Biomet peanut plates, 30 Orthofix eight-plates, and 22 Pega Medical hinge plates) were implanted in 52 patients (24 males, 28 females). Average age at implantation was 11.7 years (12.3 y in males, 11.1 y in females). Average length of follow-up was 18.4 months. There was no significant difference in rate of deformity correction between the implant types (P=0.08).Three broken screws (2.6%) were observed, all of which involved cannulated screws in peanut plates. Four peanut plates (6.3%) had an implant-related complication: 3 broken screws and 1 screw pullout. Three eight-plates (10.0%) had screw pullout. No complications were observed within either the hinge plate or solid screw groups. Implant-related complications were significantly associated with increased body weight and cannulated screw use (P=0.02 and 0.03, respectively), but not bone age, sex, plate type, or rate of deformity correction. No deep infections, premature growth arrests, or plate breakages were observed.

CONCLUSIONS

Implant-mediated guided growth is a safe technique for pediatric lower extremity angular deformity correction with a low complication rate. This study demonstrated that overweight patients had a significantly higher rate of implant-related complications. Screw breakages were only observed with cannulated screws in peanut plates. Thus, we recommend using solid, noncannulated screws in overweight children who are at an increased risk of implant failure.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Hemiepiphysiodesis for Idiopathic Genu Valgum: Percutaneous Transphyseal Screw Versus Tension-band Plate

BACKGROUND

The aim of this study was to compare the outcomes of angular deformity correction by percutaneous hemiepiphysiodesis using transphyseal screw (PETS) or tension-band plating (TBP) in growing children with idiopathic genu valgum with emphasis on the rate of deformity correction.

METHODS

We retrospectively reviewed cases of hemiepiphysiodesis for angular deformity in lower extremities between 2009 and 2014. A total of 90 limbs in 33 patients received PETS and 60 limbs in 24 patients received TBP. Angular measurements were compared preoperatively and at the time of hardware removal. The amount and rate of angular deformity correction were compared between the 2 groups. Potential factors affecting correction velocity were investigated using multivariate analysis.

RESULTS

Angular correction was achieved in all patients. The mean rate of correction was more rapid with PETS than with TBP at both the distal femur (0.92 vs. 0.64 deg./mo, respectively; P<0.001) and proximal tibia (0.72 vs. 0.55 deg./mo, respectively; P=0.019). Multivariate analysis showed that the used implant significantly affected the rate of correction: PETS demonstrated faster correction velocity than TBP (-0.26, 95% confidence interval, -0.35 to -0.17, P<0.001).

CONCLUSIONS

Both PETS and TBP techniques result in satisfactory correction of coronal angular deformity in patients with idiopathic genu valgum. However, the observed rate of correction was faster with PETS than TBP. Correction with PETS, rather than TBP, may better serve patients near skeletal maturity.

LEVEL OF EVIDENCE

Level III-retrospective comparative series.

Multiplier method may be unreliable to predict the timing of temporary hemiepiphysiodesis for coronal angular deformity

Background and purposes

The multiplier method was introduced by Paley to calculate the timing for temporary hemiepiphysiodesis. However, this method has not been verified in terms of clinical outcome measure. We aimed to (1) predict the rate of angular correction per year (ACPY) at the various corresponding ages by means of multiplier method and verify the reliability based on the data from the published studies and (2) screen out risk factors for deviation of prediction.

Methods

A comprehensive search was performed in the following electronic databases: Cochrane, PubMed, and EMBASE™. A total of 22 studies met the inclusion criteria. If the actual value of ACPY from the collected date was located out of the range of the predicted value based on the multiplier method, it was considered as the deviation of prediction (DOP). The associations of patient characteristics with DOP were assessed with the use of univariate logistic regression.

Results

Only one article was evaluated as moderate evidence; the remaining articles were evaluated as poor quality. The rate of DOP was 31.82%. In the detailed individual data of included studies, the rate of DOP was 55.44%.

Conclusion

The multiplier method is not reliable in predicting the timing for temporary hemiepiphysiodesis, even though it is prone to be more reliable for the younger patients with idiopathic genu coronal deformity.

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.

Prediction of rebound phenomenon after removal of hemiepiphyseal staples in patients with idiopathic genu valgum deformity

AIMS

Our aim was to investigate the predictive factors for the development of a rebound phenomenon after temporary hemiepiphysiodesis in children with genu valgum.

PATIENTS AND METHODS

We studied 37 limbs with idiopathic genu valgum who were treated with hemiepiphyseal stapling, and with more than six months remaining growth at removal of the staples. All children were followed until skeletal maturity or for more than two years after removal of the staples.

RESULTS

On multivariate logistic regression analysis, the rate of correction, body mass index (BMI), age, and initial valgus angle were significantly associated with a rebound phenomenon. With those characteristics, a predictive model for rebound was generated using recursive partitioning analysis. Children with a rapid rate of correction had the most frequent and severe rebound phenomenon (incidence 79%, mean 4°), whereas those with a slow rate of correction had less rebound when they had low BMI (43%, 2°) and none when the BMI was ≥ 21 kg/m(2).

CONCLUSION

This is the first study to evaluate a predictive model for a rebound phenomenon after temporary hemiepiphysiodesis in children with idiopathic genu valgum. Cite this article: Bone Joint J 2016;98-B:1270-5.

Comparative study between staples and eight plate in the management of coronal plane deformities of the knee in skeletally immature children

PURPOSE

To compare two commonly used methods of temporary hemiepiphysiodesis (staples and figure of eight plate) in the management of coronal plane deformities of the knee in skeletally immature children.

METHODS

This prospective study was conducted between November 2012 and November 2015. A total of 40 patients with 67 affected knee joints, having at least 1 year of skeletal growth remaining, were included in the study. Angular correction was measured by recording the mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and anatomical tibio-femoral angle (TFA) (for the overall alignment of lower limbs). Implant removal was done after 5° of overcorrection was achieved. The rate of correction (° per month) and complications related to each technique were recorded.

RESULTS

The most common diagnosis was idiopathic genu valgum. The overall rate of correction (TFA) was 1.2° for staples and 1.4° for eight plate (p = 0.70, not statistically significant). The correction in mLDFA was statistically better in the eight plate group, whereas an opposite trend was recorded in mMPTA. Implant-related complications were present in two cases of the staples group.

CONCLUSION

Although the overall correction rate was similar in both groups, implant-related complications were lower with figure of eight plate. In idiopathic genu valgum (the most common diagnosis), the correction was statistically better in the eight plate group. We recommend figure of eight plate over staples in managing these deformities.

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

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

A comparison between a hinged plate and screw system and a conventional tension-band plate and screw system used for correction of an angular deformity of the lower limb: an animal study

BACKGROUND

The purpose of the animal study is to introduce a newly designed hinged plate and screw system for correction of angular deformities of the lower limbs. The technique was compared with the use of a conventional tension-band plate and screw system.

METHODS

This is a randomized controlled animal trial. Eight 3-month-old Bama miniature pigs were used to establish animal models. In each animal, one leg was randomly allocated into study group and another leg into control group. Legs of the study group were corrected with a hinged plate and screw system, and legs of the control group were corrected with a conventional tension-band plate and screw system. The corrective rates of medial slope angle, medial proximal tibial angle, and angle of the two arms of the hinged plate were measured. Residual stress on the implants was also evaluated. A P < 0.05 was statistical significant.

RESULTS

At the final measurements of 18 weeks, the mean corrective rates of medial slope angle, medial proximal tibial angle, and angle of the two arms of the study group were 0.71°/week, 0.85°/week, and 2.18°/week, respectively; the data in the control group were 0.84°/week, 0.89°/week, and 2.13°/week, respectively. No significant difference was found between the groups regarding the mean corrective rates of the angles (P < 0.05). The mean residual stress in the study group was 643.35 MPa, and measurement in the control group was 1,273.63 MPa, with a significant difference (P < 0.05).

CONCLUSIONS

Compared to the conventional tension-band plate and screw system, the hinged plate and screw system may be more reliable for correction of angular deformities of the lower limb.

Correction of coronal plane deformities around the knee using a tension band plate in children younger than 10 years

BACKGROUND

Guided growth through temporary hemiepiphysiodesis has gained acceptance as the preferred primary treatment in treating pediatric lower limb deformities as it is minimally invasive with a lesser morbidity than the traditional osteotomy. The tension band plate is the most recent development in implants used for temporary hemiepiphysiodesis. Our aim was to determine its safety and efficacy in correcting coronal plane deformities around the knee in children younger than 10 years.

MATERIALS AND METHODS

A total of 24 children under the age of 10 were operated for coronal plane deformities around the knee with a single extra periosteal tension band plate and two nonlocking screws. All the children had a pathological deformity for which a detailed preoperative work-up was carried out to ascertain the cause of the deformity and rule out physiological ones. The average age at hemiepiphysiodesis was 5 years 3 months (range: 2 years to 9 years 1 month).

RESULTS

The plates were inserted for an average of 15.625 months (range: 7 months to 29 months). All the patients showed improvement in the mechanical axis. Two patients showed partial correction. Two cases of screw loosening were observed. In the genu valgum group, the tibiofemoral angle improved from a preoperative mean of 19.89° valgus (range: 10° valgus to 40° valgus) to 5.72° valgus (range: 2° varus to 10° valgus). In patients with genu varum the tibiofemoral angle improved from a mean of 28.27° varus (range: 13° varus to 41° varus) to 1.59° valgus (range: 0-8° valgus).

CONCLUSION

Temporary hemiepiphysiodesis through the application of the tension band plate is an effective method to correct coronal plane deformities around the knee with minimal complications. Its ease and accuracy of insertion has extended the indication of temporary hemiepiphysiodesis to patients younger than 10 years and across a wide variety of diagnosis including pathological physis, which were traditionally out of the purview of guided growth.

Determining the best treatment for coronal angular deformity of the knee joint in growing children: a decision analysis

This study aimed to determine the best treatment modality for coronal angular deformity of the knee joint in growing children using decision analysis. A decision tree was created to evaluate 3 treatment modalities for coronal angular deformity in growing children: temporary hemiepiphysiodesis using staples, percutaneous screws, or a tension band plate. A decision analysis model was constructed containing the final outcome score, probability of metal failure, and incomplete correction of deformity. The final outcome was defined as health-related quality of life and was used as a utility in the decision tree. The probabilities associated with each case were obtained by literature review, and health-related quality of life was evaluated by a questionnaire completed by 25 pediatric orthopedic experts. Our decision analysis model favored temporary hemiepiphysiodesis using a tension band plate over temporary hemiepiphysiodesis using percutaneous screws or stapling, with utilities of 0.969, 0.957, and 0.962, respectively. One-way sensitivity analysis showed that hemiepiphysiodesis using a tension band plate was better than temporary hemiepiphysiodesis using percutaneous screws, when the overall complication rate of hemiepiphysiodesis using a tension band plate was lower than 15.7%. Two-way sensitivity analysis showed that hemiepiphysiodesis using a tension band plate was more beneficial than temporary hemiepiphysiodesis using percutaneous screws.