Lengthening With External Fixation Is Effective in Congenital Femoral Deficiency

Femoral Lengthening in Children with Congenital Femoral Deficiency: A Systematic Review

BACKGROUND

Congenital femoral deficiency (CFD) presents a significant challenge in pediatric orthopaedics, characterized by a spectrum of congenital anomalies ranging from mild femoral shortening to complete absence of the proximal femur and hip joint. This review aims at reviewing the latest concepts of femoral limb lengthening modalities in treating CFD, to explore the efficacy, complications, and long-term outcomes of various surgical techniques.

METHODS

A comprehensive search of the literature was performed for clinical studies involving lengthening in patients with proximal focal femoral deficiency (PFFD) in several databases.

RESULTS

We analyze the evolution of limb lengthening procedures, from the Wagner and Ilizarov methods to the latest advancements in distraction osteogenesis, and assess their role in addressing the functional needs of patients. We also analyze the possible risk factors for the occurrence of complications with each method and alternatives to avoid them.

CONCLUSION

The review highlights the importance of individualized treatment plans, considering factors such as the degree of femoral deficiency and the potential for achieving a functional limb length; however, it requires a multidisciplinary approach and careful preoperative planning to optimize patient outcomes. The review underlines the need for ongoing research to refine surgical techniques and to compare them and improve the quality of life for individuals with PFFD.

LEVEL OF EVIDENCE

Level III. See Instructions for Authors for a complete description of levels of evidence.

Distraction Osteogenesis Reconstruction Following Resection of Bone Sarcomas: Surgical, Functional, and Oncological Outcomes from a Prospective Trial Analysis

BACKGROUND

While sustainable long-term function has been established for biological reconstruction with distraction osteogenesis (DO) following osseous resections, there is a paucity of published data informing surgeons and patients on important milestones in the reconstructive process. The objectives of this study were to determine when to expect complete bone healing and full weight-bearing as well as to quantify the influence of chemotherapy on the osseous regeneration process.

METHODS

Prospectively, pathological and clinical data were collected for 30 consecutive patients who underwent primary or secondary DO-based reconstruction following osseous resection from 2018 to 2021. Serial radiographs indicated the times to cortex formation and full union. An unpaired t test was used to compare the time required for full bone remodeling of segments transported with and without concurrent chemotherapy.

RESULTS

The average resection length was 13.6 cm (range, 4 to 22 cm). Patients underwent an average of 6.1 procedures (range, 1 to 14 procedures). Half (50%) of all procedures were planned, while half were unplanned procedures. All patients achieved full, independent weight-bearing at a median of 12 months (interquartile range [IQR], 9 to 16 months). For the 34 segments transported concurrently with chemotherapy, the mean bone healing index (BHI) was 2.3 ± 0.7, and the mean BHI was 1.2 ± 0.4 for the 25 segments without chemotherapy at any point during their transport (p < 0.0001).

CONCLUSIONS

All 30 patients achieved full bone healing and independent weight-bearing at a median of 1 year postoperatively and continued to show functional improvement afterward. Surgeons and patients can expect bone healing to be nearly twice as fast for segments transported after completion of systemic chemotherapy compared with segments transported concurrently with adjuvant chemotherapy.

LEVEL OF EVIDENCE

Therapeutic Level II . See Instructions for Authors for a complete description of levels of evidence.

Hip Joint Stability during and after Femoral Lengthening in Congenital Femoral Deficiency

BACKGROUND

Hip stability remains a major preoccupation during femoral lengthening in Congenital Femoral Deficiency (CFD). We aimed to review hip stability in Paley type 1a CFD patients undergoing femoral lengthening.

METHODS

A total of 33 patients with unilateral CFD, who were treated between 2014 and 2023, were retrospectively reviewed. In 20/33 cases (60.6%) the SUPERhip preparatory surgery was performed at a mean age of 4.3 years (range 2.7-8.1). The femoral lengthening using an external fixator was performed at a mean age of 7.8 years (range 4.3-14.3).

RESULTS

All patients presented with a stable hip joint after preparatory surgery and during femoral lengthening. Six cases of hip instability at a mean of 637 days after the external fixator removal were observed (range 127 to 1447 days). No significant differences between stable and unstable hips were noted for (1) Center-Edge Angle: 23.7 vs. 26.1 deg; (2) Acetabular Inclination: 12.8 vs. 11.7 deg; and (3) Ex-Fix Index: 35.6 days/cm vs. 42.4 days/cm; p > 0.05. Late hip instability was related to Coxa Vara and decreased femoral antetorsion before lengthening.

CONCLUSIONS

Late hip joint instability in Paley type 1a CFD patients may occur long after femoral lengthening despite hip morphology appearing to be normal on radiograms before and at the end of femoral lengthening. Coxa Vara, femoral torsional deformity, and posterior acetabular deficiency might be risk factors for hip instability.

SUPERhip Reconstruction Treatment in Patients with Congenital Femoral Deficiency of Paley's Classification Type 1b

BACKGROUND

Congenital femoral deficiency (CFD) is a challenging and complex condition that causes limb lengthening. We focused on the clinical and radiographic results of SUPERhip procedures in patients with congenital femoral deficiency type 1b, according to Paley's classification, prior to femoral lengthening.

METHODS

We reviewed all records and radiographs of patients who underwent this procedure between 2005 and 2020. We included 26 patients, with clinical and radiographic assessments performed during pre- and post-operative evaluations.

RESULTS

There were twenty-six patients (15 right vs. 11 left), with a mean age of 7 years (1-18). Most of the patients were female (17 patients; 65.4%). Twenty (76.9%) patients were undergoing their first procedure and six (23.1%) had already undergone a previous surgery. There was a significant improvement in all radiographic parameters, with the mean preoperative and postoperative Neck-Shaft Angle (NSA) being 72.3 ± 7.1° vs. 133.1 ± 12.7°, the Center-Edge Angle (CEA) 16.8 ± 9.8° vs. 33.5 ± 14.1°, and the Acetabular Index (AI) 27.8 ± 6.9° vs. 16.4 ± 6.8°, respectively. The complication rate was 15.4%, predominantly affecting patients under 5 years old.

CONCLUSIONS

The SUPERhip procedure is an effective and reproducible technique for clinical and radiographic correction to a significant degree in patients with Paley's type 1b CFD, in preparation for bone lengthening surgery.

What Factors Correlate With Length of Stay and Readmission After Limb Lengthening Procedures? A Large-database Study

BACKGROUND

Indications and techniques for limb lengthening procedures have evolved over the past two decades. Although there are several case series reporting on the complications and efficacy of these techniques, limited data are available on length of stay and hospital readmission rates after these procedures.

QUESTIONS/PURPOSES

(1) What is the median length of stay after lower limb lengthening procedures, and is variability in patient demographics, preoperative diagnosis, and surgical technique associated with length of stay? (2) What is the 1-year readmission rate after lower limb lengthening procedures? (3) Is variability in patient demographics, preoperative diagnosis, and surgical technique associated with varying rates of hospital readmission?

METHODS

Patients who underwent femoral or tibial lengthening from 2005 to 2015 in seven states were identified using the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases. These databases include a large, diverse group of patients across a wide range of hospitals and socioeconomic backgrounds with inclusion of patients regardless of payer. Between 2005 and 2015, there were 3979 inpatient admissions that were identified as involving femoral and/or tibial lengthening procedures based on ICD-9 procedure codes; of those, 2% (97 of 3979) of the inpatient admissions were excluded from analysis because they had ICD-9 procedure codes for primary or revision hip or knee arthroplasty, and 10% (394 of 3979) of the inpatient admissions were excluded because they involved repeated admissions of patients with previous hospitalization data within the database. This yielded 3488 patients for analysis. The median (interquartile range) age of patients was 18 years (12 to 41), and 42% (1481 of 3488) of patients were women. A total of 49% (1705 of 3469) of patients were children (younger than 18 years), 19% (675 of 3469) were young adults (18 to 34 years), 24% (817 of 3469) were adults (35 to 59 years), and 8% (272 of 3469) were seniors (60 years and older). Length of stay and rates of readmission at 1 year after the lengthening procedure were calculated. Univariate analysis was performed to examine associations between age, race, payment method, underlying diagnosis, bone lengthened, and lengthening technique with length of stay and readmission rate. Factors found to be significantly associated with the outcome variables (p < 0.05) were further examined with a multivariate analyses.

RESULTS

Included patients had a median (IQR) length of hospital stay of 3 days (2 to 4). Given the poor explanatory power of the multivariate model for length of stay (R 2 = 0.03), no meaningful correlations could be drawn between age, race, underlying diagnosis, lengthening technique, and length of stay. The overall 1-year readmission rate was 35% (1237 of 3488). There were higher readmission rates among adult patients compared with pediatric patients (odds ratio 1.78 [95% confidence interval 1.46 to 2.18]; p < 0.001), patients with government insurance compared with commercial insurance (OR 1.28 [95% CI 1.05 to 1.54]; p = 0.01), and patients undergoing lengthening via external fixation (OR 1.61 [95% CI 1.29 to 2.02]; p < 0.001) or hybrid fixation (OR 1.81 [95% CI 1.38 to 2.37]; p < 0.001) compared with lengthening with internal fixation only.

CONCLUSION

When counseling patients who may be candidates for limb lengthening, providers should inform individual patients and their caretakers on the anticipated length of hospital stay and likelihood of hospital readmission based on our findings. Adult patients, those with government insurance, and patients undergoing hybrid or external fixator limb lengthening procedures should be advised that they are at greater risk for hospital readmission. The relationship of specific patient-related factors (such as severity of deformity or associated comorbidities) and treatment-related variables (such as amount of lengthening, compliance with physical therapy, or surgeon's experience) with clinical outcomes after lower limb lengthening and the burden of care associated with hospital readmission needs further study.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bifocal femoral lengthening assisted by preoperative 3-dimensional design in the restoration of posttraumatic limb length discrepancy

Background

To assess the clinical outcomes of preoperative three-dimensional planning followed by bifocal femoral lengthening in the treatment of posttraumatic limb length discrepancy (LLD).

Methods

A total of 8 eligible patients with posttraumatic femoral LLD > 6 cm were admitted to our institution from January 2015 to January 2018 and treated by bifocal femoral lengthening with the assistance of 3-dimensional imaging technology. The following data were collected: detailed demographic information, the amount of lengthening, external fixation time (EFT), external fixation index (EFI), postoperative bone and functional outcomes, and complications in the follow-up period.

Results

All included patients were successfully followed up for in an average of 55.4 ± 6.7 months after removal of the external fixator. There were six males and two females with an average age of 38.4 ± 12.2 years. The mean preoperative LLD was 69.2 ± 6.2 mm. The mean lengthening amount was 67.5 ± 6.9 mm. The mean EFT was 180.1 ± 20.2 days. The EFI was 26.73 ± 1.36 days/cm on average. All patients achieved satisfactory postoperative bone and functional outcomes. No major complications such as nerve or vascular injury were observed.

Conclusions

Bifocal femoral lengthening with preoperative three-dimensional design provided precise surgical guidance and resulted in satisfactory postoperative outcomes, demonstrating that it is an effective treatment for posttraumatic femoral LLD.

Comparison of Three Circular Frames in Lower Limb Deformity Correction: A Biomechanical Study

Background

The use of circular frames in correcting lower limb deformity is well-established and has evolved dramatically over the years. Three new frames have been introduced recently, and this study is set to compare them in terms of accuracy and efficiency in correcting a similar long bone deformity. These frames are the Taylor Spatial Frame (TSF; Smith & Nephew, London, United Kingdom), the Truelok Hexapod System (TL-HEX; Orthofix, Lewisville, Texas), and Orthex (OrthoPediatrics, Warsaw, Indiana).

Methods

This is a biomechanical study comparing the above three types of circular frames to correct similar deformities in Sawbones models. The deformities that are compared were: (1) 30° valgus deformity of the distal femur; (2) 30° varus deformity of the proximal tibia.

Each frame was applied to the deformed bone in the standard way that we apply to normal bone. X-rays were taken before and after the deformity correction. The frames’ software was used to estimate the deformities. The variations between the software’s estimations and the known bone deformities were compared. Residual deformity after initial correction and the number of re-programmings was compared among these three frames. The least residual deformity and re-programming is the favorable outcome.

Results

All the Sawbones models had a 30° actual coronal angulation. The Orthex software estimated the deformity at around 25.35° (SD 4.6), TSF 25.6° (SD 2), and TL-HEX 29.87° (SD 2.1). One-way analysis of variance (ANOVA) showed a significant difference in the findings (P-value 0.014).

Accuracy was measured by comparing the residual deformity in angulation in the coronal plane after the first and second correction. The Orthex median residual deformity was 1°, TSF was 2.5°, and TL-HEX was 3° with a range of less than 5° for all of them. The independent samples Kruskal-Wallis test shows that there is no significant difference between the three groups (P=0.549).

The frequency of strut changes required throughout the correction was not significant among the three frames using the Fisher exact test (P=0.336). TSF struts are not designed to be readjusted.

Conclusion

The three frames were comparable in terms of accurate correction of the two deformities, strut changes, and strut adjustments. The TL-HEX frame software was superior to other frames in terms of analyzing the deformity but the difference, although statistically significant clinically, was not.

Femoral Lengthening in Children-A Comparison Between Magnetic Intramedullary Lengthening Nails and External Fixators

BACKGROUND

Femoral lengthening can be achieved using external fixators or intramedullary lengthening nails. The purpose of this research was to compare the outcome of femoral lengthening in children using PRECICE magnetic lengthening nails with lengthening external fixators.

METHODS

Retrospective analysis of 50 children who had femoral lengthening. Group A included patients who had lengthening with external fixation, patients in Group B had lengthening with PRECICE intramedullary lengthening nails. Each group included 25 patients. The sample strictly included children aged between 11 and 17 years. Patients in each group were matched according to age and indication for lengthening whether congenital or acquired conditions. The outcomes focused on the ability to achieve target length, healing index, residual malalignment, length of hospitalization following the osteotomy surgery, and encountered complications.

RESULTS

Mean patient age was 14.7 years for each group. The length gain was 42±12 mm for Group A and 41.6±8 mm for Group B (P=0.84). Lengthening nails achieved the target length more accurately compared with external fixation (P=0.017). The healing index was significantly higher in group A with 53.2±19 days/cm compared with 40.2±14 days/cm in group B (P=0.03). Group A had significantly higher complications than group B (P<0.0001). There was no statistically significant difference in the final coronal malalignment between the 2 groups (P=0.2). The mean length of stay was 9.2±5.8 days for group A and 4.2±3.3 days for group B (P=0.0005).

CONCLUSION

Magnetic lengthening nails are clinically effective for femoral lengthening in the pediatric population. Compared with external fixation, healing index and complications were more favorable with PRECICE nails. Further research is required to study the cost-effectiveness of this technique.

LEVEL OF EVIDENCE

Level IV-case series.

Comparison of Intramedullary Magnetic Nail, Monolateral External Distractor, and Spatial External Fixator in Femur Lengthening in Adolescents with Congenital Diseases

The aim of this study is to evaluate the course of the treatment and clinical and functional outcomes of femur lengthening in adolescents with congenital disorders by the application of different surgical methods. This retrospective study comprised 35 patients (39 procedures). A total of 11 patients underwent femur lengthening with the use of the intramedullary magnetic nail (IMN) Precise 2 (NuVasive, San Diego, CA, USA), 7 patients (11 procedures) with the use of the monolateral external distractor Modular Rail System (MRS) (Smith and Nephew, Memphis, TN, USA), and 17 with the use of the computer-assisted external fixator Taylor Spatial Frame (TSF) (Smith and Nephew, Memphis, TN, USA). The inclusion criteria were as follows: (1) congenital femoral length deficiency without any axial deformities and (2), independently of the finally applied treatment, the technical possibility of use of each of the analyzed methods. The distraction index did not differ significantly between the groups (p = 0.89). The median lengthening index was the lowest in the IMN group (24.3 d/cm; IQR 21.8–33.1) and statistically different in comparison to the MRS (44.2 d/cm; IQR 42–50.9; p < 0.001) and the TSF groups (48.4 d/cm; IQR 38.6–63.5; p < 0.001). Similarly, the consolidation index in the IMN group (12.9 d/cm; IQR 10.7–21.3) was statistically lower than that in the MRS (32.9 d/cm; IQR 30.2–37.6; p < 0.001) and the TSF (36.9 d/cm; IQR 26.6–51.5; p < 0.001) groups. This study indicates that IMN is a more valuable method of treatment for femoral length discrepancy without axial deformity than MRS and TSF in complication rate and indexes of lengthening and consolidation.

Femoral lengthening in young patients: An evidence-based comparison between motorized lengthening nails and external fixation

BACKGROUND

Femoral lengthening is a procedure of great importance in the treatment of congenital and acquired limb deficiencies. Technological advances have led to the latest designs of fully implantable motorized intramedullary lengthening nails. The use of these nails has increased over the last few years.

AIM

To review and critically appraise the literature comparing the outcome of femoral lengthening in children using intramedullary motorized lengthening nails to external fixation.

METHODS

Electronic databases (MEDLINE, CINAHL, EMBASE, Cochrane) were systematically searched in November 2019 for studies comparing the outcome of femoral lengthening in children using magnetic lengthening nails and external fixation. The outcomes included amount of gained length, healing index, complications and patient reported outcomes.

RESULTS

Of the 452 identified studies, only two (retrospective and non-randomized) met the inclusion criteria. A total of 91 femora were included. In both studies, the age of patients treated with nails ranged from 15 to 21 years compared to 9 to 15 years for patients in the external fixation group. Both devices achieved the target length. Prevalence of adverse events was less in the nail (60%-73%) than in the external fixation (81%-100%) group. None of the studies presented patient reported outcomes.

CONCLUSION

The clinical effectiveness of motorized nails is equivalent or superior to external fixation for femoral lengthening in young patients. The available literature is limited and does not provide evidence on patient quality of life or cost effectiveness of the interventions.

The knee in congenital femoral deficiency and its implication in limb lengthening: a systematic review

Congenital femoral deficiency (CFD) is a rare disorder with several limb anomalies including limb shortening and knee cruciate ligament dysplasia.

Limb lengthening is usually performed to correct lower limb discrepancy. However, complications, such as knee subluxation/dislocation, can occur during this treatment.

Here, we explore CFD knee abnormalities and knee dislocation during limb elongation, discussing when and whether knee ligament reconstruction prior to the lengthening would be necessary to reduce the risk of knee dislocation.

There is not enough support in the literature for the routine reconstruction of cruciate ligaments in CFD patients.

Of note, in cases of severe anteroposterior or posterolateral rotatory instability, cruciate ligament reconstruction might be considered to decrease the risk of knee subluxation/dislocation during the lengthening treatment.

Cite this article: EFORT Open Rev 2021;6:565-571. DOI: 10.1302/2058-5241.6.200075

Limb Lengthening for Congenital Deficiencies Using External Fixation Combined With Flexible Intramedullary Nailing: A Multicenter Study

BACKGROUND

Hydroxyapatite (HA) coated flexible intramedullary nailing (FIN) stimulates osteogenic activity. The role of HA-coated intramedullary nails remains unclear in normal bone lengthening. The goal of this study was to quantify the influence of FIN on the External Fixation Index (EFI) in patients with congenital lower limb discrepancy.

METHODS

Patients with femoral deficiency and fibular hemimelia underwent lengthening by the combined technique of external fixation with titanium (Ti) FIN or HA coated FIN and returned for follow-up at least 12 months after frame removal.

RESULTS

Seventy patients (mean age of 12.6 y) were included: 19 monofocal femoral lengthenings, 35 tibial monofocal lengthenings, 16 tibial bifocal lengthenings. The mean EFI's for those treated with and without HA-coated nails were not significantly different. The Conover posthoc analysis did not reveal a significant influence of the type of FIN on EFI in any subgroup. However, 2-way analysis of variance revealed simultaneous effects of nail types and age on the EFI in tibial bifocal lengthening.Significant positive correlation between the ratio "nail diameter/medullary shaft diameter" and EFI in tibial bifocal non-HA-coated FIN lengthening, and a significant positive correlation between age and EFI for femoral non-HA-coated FIN lengthening, tibial monofocal and bifocal HA-coated FIN lengthening were revealed.There were 4 cases of fracture at lengthening site required unscheduled surgery. In the non-HA-coated group, there was a statistically significant negative correlation between nail diameter and fracture occurrence at the lengthening site after frame removal. A ratio of <0.15 likely does not ensure required mechanical stability and support.

CONCLUSIONS

Both Ti-nail and HA-coated nail lengthening provide good and excellent outcomes for femoral and tibial monosegmental lengthening procedures and ensure reduced EFI. In congenital disorders which were not associated with abnormal bone, there are no differences with regard to EFI using HA-coated or non-HA-coated FIN. The ratio of "elastic Ti-nail diameter/medullary canal diameter at narrowest site" <0.15 seems to be associated with higher risk of fracture at the lengthening site after frame removal.

Rotationplasty for Severe Congenital Femoral Deficiency

Rotationplasty is a reconstructive option for severe congenital femoral deficiency (CFD). The senior author (D.P.) developed five new rotationplasty techniques for use in CFD based on the Paley classification, including the Paley–Brown (fusion femur to pelvis), Paley (fusion femur to femoral head), Paley–Winkelman (insertion tibial condyle to acetabulum), PaleySUPERhip–Van Nes (hip osteotomy with knee fusion) and PaleySling–Van Nes (hip reconstruction with knee fusion revision) rotationplasty techniques. The purpose of this study is to retrospectively evaluate the complications, radiographic outcomes and need for secondary surgery in 19 rotationplasty cases performed by the senior author (D.P.) for severe CFD from 2009 to 2019. Rotationplasty comprised only 2% of the authors treated CFD cases during this period. Average age at surgery was 8.6 years old. Average follow-up was 3.3 years. Sixteen concomitant procedures were performed including temporary arthrodesis, tibial osteotomy and SUPERhip procedure. The most common complication was wound necrosis/dehiscence, which occurred in 52% of the cases related to the circumferential incision and required a total of 31 additional debridements. Additional complications were successfully treated and included sciatic nerve palsy decompressed by abducting the femur, a tibial delayed union that underwent bone grafting, two distal femur failed epiphysiodesis treated by revision with one osteotomy and a thigh compartment syndrome requiring debridement. Indication specific rotationplasty successfully addresses the severe degree of femoral deficiency, deformity, and discrepancy in patients with CFD, despite high rates of wound complications.

Extramedullary Motorized Lengthening of the Femur in Young Children

BACKGROUND

Limb lengthening by distraction osteogenesis is now achievable via motorized intramedullary devices, mitigating many complications of lengthening by external fixation. In young patients, antegrade intramedullary nailing of the femur risks avascular necrosis of the femoral head. A method of extramedullary placement of a motorized expandable intramedullary nail has been employed by the senior author to safely achieve femoral lengthening without the use of an external fixator in young patients.

METHODS

Eleven skeletally immature patients with lower limb length discrepancy were reviewed who underwent extramedullary placement of a magnetic, expandable intramedullary nail for lengthening of the femur. Surgical details, lengthening parameters, and complications were reviewed and classified according to the modified Clavien-Dindo Classification.

RESULTS

Average lengthening was 32.3 mm (range: 27 to 40 mm) comprising an average 14.8% of femoral segment length. The average lengthening duration was 6.3 weeks, and average full weight-bearing began at 12.6 weeks. All but 1 patient underwent early removal of the device at an average of 4.5 months, and 5 had immediate plating of the femur. Complications rates were comparable to other methods of femoral lengthening, including varus or procurvatum through the regenerate, and unplanned reoperation in 3 of 11 cases. Preoperative considerations included careful planning of implant length due to short femoral segments and protection of the knee joint from contracture or iatrogenic instability.

CONCLUSIONS

Extramedullary placement of a magnetic expandable intramedullary lengthening nail can achieve lengthening of the femur without the use of external fixation. Considerations with this technique include careful planning of implant length relative to trochanteric-physeal distance, protection against knee subluxation during lengthening, and mitigating deformity of the regenerate. Off-label, extramedullary use of these devices can be considered to decrease the burdens of external fixation in young children. The technique begs the advent of future all-internal technology specifically designed for safe limb lengthening in this age group.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Anatomic Relationship of the Femoral Neurovascular Bundle in Patients With Congenital Femoral Deficiency

BACKGROUND

Congenital femoral deficiency (CFD) is a rare condition that affects the morphology of the hip and surrounding soft tissues. Bony deformity and distorted muscular anatomy are well known, but no studies have described the relationship of the femoral neurovascular (NV) bundle to surgically relevant anatomic landmarks. The authors compared the location of the femoral NV bundle on the affected side in patients with CFD with the unaffected side. The authors hypothesized that the bundle on the pathologic side would be in an abnormal position relative to the unaffected side.

METHODS

Thirty-three patients diagnosed with unilateral CFD who had undergone preoperative magnetic resonance imaging of the pelvis were included in our study. The authors identified the femoral NV bundle on the axial cuts and measured its distance from the anterior superior iliac spine (ASIS), anterior inferior iliac spine (AIIS), and lesser trochanter (LT). Anatomic percent change and absolute measurements were then compared and correlated with associated boney deformities and the Paley classification.

RESULTS

The distance from the femoral NV bundle to the ASIS, AIIS, and LT was significantly different compared with the unaffected side. The AIIS absolute distance and AIIS percent change significantly correlated with the neck-shaft angle of the proximal femur.

CONCLUSIONS

In patients with CFD, the femoral NV bundle seems to be further from the LT and closer to the AIIS on the affected side when compared with the unaffected side. magnetic resonance imaging may be helpful to understand the course of the femoral NV bundle before reconstruction in patients with CFD; however, the authors recommend identification of the femoral NV bundle before transection of the proximal rectus femoris tendon to provide safe surgical care.

LEVEL OF EVIDENCE

Level IV-case-control study of diagnostic studies.

What's New in Pediatric Limb Lengthening and Deformity Correction?

Over the past 5 years, published literature regarding treatment of pediatric limb deformity and limb length discrepancy demonstrates much interest in better understanding, categorizing and treating these challenging problems. Many studies explore expanding and refining indications for traditional treatment methods like guided growth techniques. Other studies have evaluated the results of new techniques such as lengthening via mechanized intramedullary nails. Additionally, series comparing older and newer techniques such as lengthening with external devices versus mechanized nails are becoming increasingly available.

Lengthening With Monolateral External Fixation Versus Magnetically Motorized Intramedullary Nail in Congenital Femoral Deficiency

BACKGROUND

Limb lengthening for congenital femoral deficiency (CFD) with or without fibular hemimelia can be performed with both external and internal devices. The purpose of this study is to compare clinical outcomes of femoral lengthening utilizing monolateral external fixation versus a magnetically motorized intramedullary nail in patients with CFD with or without fibular hemimelia.

METHODS

This retrospective review included 62 patients with femoral lengthening, 32 patients had monolateral external fixation (group A), 30 patients had internal lengthening nail (group B). Mean age in years was 9.4±3.8 and 15.4±4.9 for groups A and B, respectively. Mean follow-up in years was 4.47±2.7 and 1.86±0.7 years for groups A and B, respectively.

RESULTS

Mean lengthening achieved was 5.6±1.7 and 4.8±1.4 cm for group A and group B, respectively (P=0.052). Mean distraction index was 0.7±0.2 mm/d for group A and 0.7±0.2 mm/d for the group B (P=0.99). Mean consolidation index for group A was 29.3±12.7 and 34.8±11.2 d/cm for group B (P=0.08). Mean arc of motion before surgery and at final follow-up were similar between groups (P=0.35). Group A had significantly less range of motion at the end of distraction (P=0.0007) and at consolidation (P<0.0001). Both groups had similar rates of obstacles and complications. A significant difference between groups was found in the total problems (P<0.001) specifically with pin site/superficial infection (P<0.0001).

CONCLUSIONS

The intramedullary nail had superior range of motion during the lengthening phase and at consolidation and an overall lower problem complication rate, while maintaining similar distraction and healing indices to monolateral external fixation. Internal lengthening nails represent a significant advance in technology for CFD lengthening.

LEVEL OF EVIDENCE

Level IV-therapeutic.

The role of external fixation in paediatric limb lengthening and deformity correction

Limb deformity and shortening remains a common presenting complaint in paediatric orthopaedics. The ability to restore length, alignment with consistent bone formation allows standardised treatment in these difficult conditions. The use of an external fixator produces a stable construct which allows manipulation of the bone segments, with a controlled rate and rhythm. Deformity analysis permits the surgeon to plan osteotomy levels and frame application to produce accurate correction. Complications, especially in congenital conditions remain an issue and modification of the treatment is required to try and reduce their incidence. New types of fixators, the latest being hexapod frames, have increased the versatility in deformity correction. The aim of this paper is to review the use of external fixators in elective paediatric orthopaedics and highlight the latest changes in technique and application for the limb reconstruction surgeon.

The risks following the exposure to radiation associated with the surgical correction of limb deformities in children are minimal

Aims

The aim of this study was to quantify the risk of developing cancer from the exposure to radiation associated with surgery to correct limb deformities in children.

Patients and Methods

A total of 35 children were studied. There were 19 girls and 16 boys. Their mean age was 11.9 years (2 to 18) at the time of surgery. Details of the radiological examinations were recorded during gradual correction using a Taylor Spatial Frame. The dose area product for each radiograph was obtained from the Computerised Radiology Information System database. The effective dose in millisieverts (mSv) was calculated using conversion coefficients for the anatomical area. The lifetime risk of developing cancer was calculated using government-approved Health Protection Agency reports, accounting for the age and gender of the child.

Results

Correction was undertaken in five femurs, 18 tibiae, and 12 feet. The median duration of treatment was 45 months (11 to 118). The mean effective dose was 0.31 mSv (0.05 to 0.64) for the femur, 0.29 mSv (0.01 to 0.97) for the tibia, and 0.027 mSv (0.001 to 0.161) for the foot. The cumulative exposure gave ‘negligible’ risk in 26 children and ‘minimal’ risk in nine children, according to Public Health England categories. These results are below the mean annual background radiation in the United Kingdom.

Conclusion

The lifetime attributable risk of developing cancer from repeated exposure to radiation was negligible or minimal in all children. This is the first study to quantify the exposure to radiation from serial radiographs in children with limb deformities who are treated surgically using circular external fixation, linking this to the risk of developing cancer. Cite this article: Bone Joint J 2019;101-B:241–245.

Reconstruction of Symptomatic Congenital Anterior Cruciate Ligament Insufficiency

BACKGROUND

Hypoplasia or congenital absence of the anterior cruciate ligament (ACL) is a rare disorder occurring in ∼1 in every 6000 births. Although some patients with hypoplasia or agenesis of the ACL may not complain of instability, others desire to participate in more demanding activities that require the stability of a competent ACL. There are limited reports of surgical treatment of this patient population. The purpose of this study was to report ACL reconstruction in a case series of patients with symptomatic congenital ACL deficiency.

METHODS

A retrospective medical record review of the surgical treatment of 14 knees (13 patients) with congenital absence of the ACL at a tertiary care institution from 1995 to 2012 was performed. Patients with a minimum of 1 year of clinical follow-up were eligible for inclusion.

RESULTS

The mean age at time of surgery was 12.6 (range, 3 to 22), including 6 patients <12 years of age. Mean follow-up was 2.9 years (range, 1 to 6.6). Nine of 13 patients (69%) had underlying congenital abnormalities/associated syndromes. Preoperative Lachman and pivot shift examination was International Knee Documentation Committee grade C or D in all but 1 knee. ACL reconstruction was performed with combined intra-articular/extra-articular physeal sparing reconstruction with iliotibial band (n=5), autograft hamstring (n=2) or bone-patellar tendon-bone (n=3), or allograft (n=4). Multiligament reconstruction of associated ligamentous deficiency was performed in 7 knees (50%). Postoperative Lachman and pivot shift testing was International Knee Documentation Committee (IKDC) grade A or B in all but 1 knee. One patient with congenital absence of multiple knee ligaments required revision ACL reconstruction surgery, with concurrent first-time posterior cruciate ligament reconstruction, due to persistent instability. None required revision surgery due to graft tear at a minimum of 1-year follow-up.

CONCLUSIONS

Surgical stabilization of symptomatic congenital ACL insufficiency, with associated ligamentous reconstruction as required on a case-by-case basis, results in improved stability at early clinical follow-up, with low complication rates.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

A Rare Case of Congenital Tibiofemoral Fusion with Bilateral Proximal Femoral Focal Deficiency: A Case Report

CASE

We report a unique combination of neonatal bilateral proximal femoral focal deficiency with a congenital tibiofemoral fusion of the right leg.

CONCLUSION

To the best of our knowledge, the combination of proximal femoral focal deficiency and the congenital absence of the knee joint in a child has not previously been reported.

Femoral lengthening in children and adolescents

Current lengthening techniques are still based on the Ilizarov method and the concept of callotasis. Research and progress in medical devices have led to constant improvement in results. Hexapod fixators allow more precise correction of complex deformities, with shorter learning curve. Associating lengthening by external fixation (EF) to internal fixation (K-wire, intramedullary nail or locking plate) has reduced EF times and complications rates, while improving anatomic and functional results. Lengthening nails provides faster recovery of range of motion and return to activity during lengthening and consolidation, with better psychological tolerance. Lengthening with deformity correction by retrograde nailing has no impact on consolidation. Monolateral EF is a reliable and easy-to-implement technique that is well tolerated by patients. Association to internal fixation gives promising results. Bone healing solidity assessment on plain X-ray is highly subjective, with wide inter- and intra-observer variation; bone mineralization is better assessed in terms of pixel-value ratio (PVR: ratio of pixel value of regenerate to adjacent bone) on picture archiving and communication system (PACS) digitized radiographs, providing objective assessment of callus solidity.

Lower extremity growth and deformity

The pediatric lower extremity has well known growth patterns. When deformities or growth disturbances occur, there are several methods to measure and predict the resulting discrepancy, including the Green-Anderson, Moseley, and Multiplier methods. Many techniques exist to correct leg length discrepancy and deformity such and temporary epiphysiodesis, permanent epiphysiodesis, external fixators, and internal lengthening devices. All of these methods have numerous complications and limitations; however, with careful planning and patient selection, length and alignment can be improved with high patient satisfaction.

The unstable knee in congenital limb deficiency

PURPOSE

Instability of the knee is a common finding in patients with congenital limb deficiency. The instability can be attributed to soft tissue abnormalities, frontal, sagittal or rotational deformity of the lower limb and bony dysplasia of the patella or of the femoral condyles. In most of the cases, these pathomorphologic changes stay asymptomatic in daily activity. However, instability can appear during deformity correction and bone-lengthening procedures, leading to flexion contracture or subluxation of the knee.

METHODS

A review of pediatric orthopaedic literature on different factors of knee instability, state-of-the-art treatment options in congenital limb deficiency and in cases of lengthening-related knee subluxation is presented and the authors' preferred treatment methods are described.

RESULTS

Leg lengthening and deformity correction in patients with congenital limb deficiencies can be achieved with various techniques, such as guided growth, monolateral or circular external fixation and intramedullary lengthening nails. Radiographic assessment and clinical examination of the knee stability are obligatory to estimate the grade of instability prior to surgical procedures. Preparatory surgery, as well as preventive measures such as bracing, bridging of the knee and intensive physical therapy, can help to avoid subluxation during lengthening in unstable knees.

CONCLUSIONS

Adequate surgical techniques, preventive measures and early detection of signs of subluxation can lead to good functional results in patients with congenital limb deficiency.