Evaluation of complications of treatment of severe Blount's disease by circular external fixation using a novel classification scheme

Recurrence and Complication Rates of Surgical Treatment for Blount's Disease in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Blount's disease is a growth disorder of the proximal tibia that causes progressive genu varum in children. Surgical treatment is recommended if the deformity worsens, but which intervention is best remains controversial. This study aims to identify factors influencing outcomes and determine the most effective surgical approach.

METHODS

A systematic review was conducted of studies published before January 2022.

RESULTS

In total, 63 retrospective studies with CEBM IIIb/IV levels were included (1672 knees in 1234 patients). The most commonly reported treatment was acute correction via osteotomy (47%), followed by hemiepiphysiodesis (22%) and gradual correction (18%). Combined procedures were reported in 13% of cases. The overall recurrence rate was 18%, with a significant difference when comparing the recurrence rates after gradual correction with those after hemiepiphysiodesis (7% and 29%, respectively). Major complications beyond recurrence were observed in 5% of cases. A meta-analysis of the available raw data showed a significantly increased recurrence rate (39%) among treated children who were between 4.5 and 11.25 years of age and were followed for a minimum follow-up of 2.5 years.

CONCLUSIONS

Overall, poor evidence with which to establish an optimal treatment for Blount's disease was found. This study remarked on the need for early diagnosis, classification, and treatment of infantile tibia vara, since a significant rate of recurrence was found in neglected cases.

Complications and risk factors of intramedullary bone lengthening nails: a retrospective multicenter cohort study of 314 FITBONE and PRECICE nails

BACKGROUND AND PURPOSE

Intramedullary bone-lengthening nails have become increasingly popular. The 2 most used and successful nails are the FITBONE and the PRECICE nails. Uniform reporting is lacking on complications of intramedullary bone-lengthening nails. The purpose was therefore to assess and categorize the complications of lower limb bone-lengthening nails and investigate risk factors.

PATIENTS AND METHODS

We performed a retrospective review of patients operated on with intramedullary lengthening nails at 2 hospitals. We included only lower limb lengthening with FITBONE and PRECICE nails. Recorded patient data was patient demographics, nail information, and any complication. Complications were graded according to severity and origin classification. Complication risk factors were assessed with modified Poisson regression.

RESULTS

314 segments in 257 patients were included. The FITBONE nail was predominantly used (75%), and most of the lengthenings were performed in the femur (80%). 53% of the patients had complications. 269 complications were identified in 175 segments (144 patients). Device-related complications were most frequent (0.3 complications/segment), followed by joint complications (0.2 complications/segment). An increased relative risk was found for complications in the tibia compared with the femur and for age groups above 30 years compared with the 10-19 years group.

CONCLUSION

Complications with intramedullary bone lengthening nails were more frequent than has previously been reported, with 53% of patients sustaining a complication. Future studies need to document the complications meticulously so that the true risk can be established.

Mechanical Failures in Magnetic Intramedullary Lengthening Nails

BACKGROUND

Magnetic intramedullary lengthening nails (MILNs) have gained popularity in recent years for the treatment of limb-lengthening discrepancies. We sought to catalog mechanical failures and their prevention and management in a large, single-institution series. We specifically assessed the rate of mechanical failures, the types of failures observed, and management strategies.

METHODS

We retrospectively reviewed 377 patients (420 limbs) who underwent limb lengthening with early (P1) or later (P2) MILN iterations with ≥12-month follow-up. Mechanical failure was defined as mechanical breakage of the instrumentation or nail and/or failure of the internal lengthening mechanism. Failure assessment was arranged by lengthening phases and was sorted with a complication classification system. All lengthening and alignment parameters were assessed radiographically.

RESULTS

Mechanical failure was observed in 40 nails (9.5%), most of which (63%) were corrected with an additional surgical procedure. The mechanical failure rate was 11.3% in P1 nails and 9% in P2 nails. Two nails failed the intraoperative distraction test, and 1 nail was found to have a broken washer during the insertion phase. Sixteen nails had mechanical failures in the lengthening phase. Some nails (8 of 16) required nail replacement surgery. Thirteen nails failed during the consolidation phase; 7 of these cases were managed by replacement with either a functional MILN or a conventional intramedullary nail. Eight failures happened during the extraction phase and were managed intraoperatively.

CONCLUSIONS

A 9.5% overall rate of mechanical failure of MILNs was observed in this large series. Resolution was achieved with an additional surgery in most cases. Nail distraction and weight-bearing compliance should be closely monitored during the lengthening and consolidation phases. Nail removal can be difficult and requires a careful study of radiographs for locking-screw bone overgrowth and backup removal equipment.

LEVEL OF EVIDENCE

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

Do Surgeons Agree on Severity and Origin of Complications in Bone-lengthening Nails? An Inter- and Intra-rater Reliability Study

Background

Bone-lengthening nails result in various complications with different severity and origin. However, no universal reporting system for complications has been agreed upon, making it difficult to compare different nail designs and patient populations. This study aimed to assess the inter- and intra-rater agreement of a classification system of complications according to severity and origin.

Materials and methods

Four orthopaedic surgeons assessed 48 complications retrieved from patient charts in a single-centre cohort and 49 literature complications cases. Complications were classified according to severity grading (I, II, IIIA and IIIB) from Black et al. and origin with eight main types and 33 subtypes. A blinded independent assessment was performed twice at least six weeks apart. Cohen/Congers kappa estimated for the inter- and intra-rater agreement was interpreted after Svanholm et al.

Results

The surgeons had a good inter-rater agreement for complication severity with a kappa value of 0.68 [95% confidence interval (CI): 0.56-0.79] and complication origin with a kappa value of 0.63 (CI: 0.53-0.73), respectively, on the cohort cases. In literature cases, a good agreement on complication severity and origin grading was shown by kappa values of 0.64 (CI: 0.53-0.75) and 0.74 (CI: 0.65-0.83). The intra-rater assessment of complication severity and origin grading had good to excellent agreement with kappa values ranging from 0.51 to 0.97.

Conclusion and clinical significance

The study presents the first structured complication classification on severity and origin in intramedullary bone-lengthening nails. A good reproducibility agreement in both severity and origin was found between four orthopaedic surgeons for both cohort and literature complication cases. For clinical and research purposes, a shared language for communicating complications is essential. We encourage future studies to use a structured and validated complication classification.

How to cite this article

Frost MW, Rahbek O, Fridberg M, et al. Do Surgeons Agree on Severity and Origin of Complications in Bone-lengthening Nails? An Inter- and Intra-rater Reliability Study. Strategies Trauma Limb Reconstr 2022;17(3):153-158.

Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount\'s Disease

Aim

To evaluate the results in terms of correction and complications from gradual correction with a computer-assisted hexapod circular external fixator in a mixed cohort of children with Blount's disease.

Materials and methods

A retrospective review was performed of the correction and complications of 19 children (25 limbs) with recurrent infantile (IBD) and late-onset Blount's disease (LOBD) treated by gradual correction with a hexapod external fixator. The correction was measured by the medial proximal tibial angle (MPTA), anatomic posterior proximal tibial angle (aPPTA) and anatomic tibio-femoral angle (TFA). Obesity was present in 76% (19/25) of cases. Fifteen limbs were classified as infantile Blount's disease and 10 limbs as late-onset Blount's disease. The mean age was 12.5 years (range 7–17 years).

Results

The mean pre-operative MPTA of 59° (SD 13°, range 33–79°) was corrected to a mean of 86° (SD 5°, range 77–93°). The mean pre-operative aPPTA of 64° (SD 14°, range 33–84°) was corrected to 79° (SD 6°, range 70–90°). The median pre-operative rotation of 15° internal rotation was corrected to normal (0–15° of external rotation). Eight out of 25 limbs had severe deformities with varus or procurvatum greater than 40° or both. The mean pre-operative TFA of 28° varus (SD 13°, range 4–53°) was corrected to 1.8° valgus (SD 6°, range 14° varus to 13° valgus). The median follow-up was 19 months (range 6–67 months). The alignment after correction was “good” in 55% (11/20), “acceptable” in 35% (7/20) and “poor” in 10% (2/20).

The median duration for correction was 16 days (IQR 11–31 days, range 7–71 days). The median number of prescribed correction programmes was 1 (IQR 1–2, range 1–5). The mean total time in the frame was 136 days (SD 34 days, range 85–201 days).

All patients developed minor pin track infections that resolved with oral antibiotics (Category 1 complications). Four patients developed complications that necessitated modification of the treatment plan (Category 2 complications). In two cases, treatment objectives could not be achieved (Category 3 complications). Two patients treated before skeletal maturity developed recurrent genu varum.

Conclusion

Gradual correction with a computer-assisted hexapod external fixator may be a useful technique for correcting recurrent IBD or LOBD even in children with severe deformities. The results of gradual correction were similar in the two groups. While complications occur, most can be mitigated by timely intervention during the correction phase of treatment. Recurrence remains a concern if correction is performed before skeletal maturity.

Level of evidence

4.

How to cite this article

Mare PH, Marais LC. Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount's Disease. Strategies Trauma Limb Reconstr 2022;17(1):32–37.

Challenges with Fassier-Duval rod exchanges in congenital pseudarthrosis of the tibia: explant roadblock and solution

Congenital pseudarthrosis of the tibia (CPT) is characterized by anterolateral tibial bowing and hamartomatous periosteum that predisposes it to fracture. Fassier-Duval telescopic rods can improve the structural integrity of bone segments after reconstruction. We present our experience treating CPT with the Fassier-Duval rod and a novel technique for Fassier-Duval exchange that was developed after extraction failed in one patient. Patients were identified who underwent treatment with Fassier-Duval rods for CPT between 2007 and 2016 and had undergone their first rod exchange. Medical records were reviewed, and complications were classified using the system of Cherkashin. Four patients had an average age at the initial insertion of 6 years 4 months (4-9 years). The average follow-up duration after initial Fassier-Duval implantation was 5.4 years (2.7-8.1 years). Seven Category 2 complications were associated with the Fassier-Duval rod: interlocking K-wire migration (2), lengthening failure (2), explant failure (1), distal migration of female rod through physis (1) and male rod portion proximally migrating through physis (1). Three patients underwent one rod exchange [average 3.2 years after implantation (range, 2.7-3.9 years)]. One patient underwent two rod exchanges (2.9 and 6.9 years after initial implantation). The second attempt at exchange failed; this failure prompted the development of custom trephines to remove the hard bone that can encase the distal male segment. The use of custom trephines was made necessary by dense sclerotic bone at the previous pseudarthrosis site. We recommend that custom trephines be available during Fassier-Duval rod extraction to avoid failed retrieval. Level of evidence: Level IV (Case series).

Deformity Reconstruction Surgery for Blount's Disease

Blount's disease is an idiopathic developmental abnormality affecting the medial proximal tibia physis resulting in a multi-planar deformity with pronounced tibia varus. A single cause is unknown, and it is currently thought to result from a multifactorial combination of hereditary, mechanical, and developmental factors. Relationships with vitamin D deficiency, early walking, and obesity have been documented. Regardless of the etiology, the clinical and radiographic findings are consistent within the two main groups. Early-onset Blount's disease is often bilateral and affects children in the first few years of life. Late-onset Blount's disease is often unilateral and can be sub-categorized as juvenile tibia vara (ages 4-10), and adolescent tibia vara (ages 11 and older). Early-onset Blount's disease progresses to more severe deformities, including depression of the medial tibial plateau. Additional deformities in both groups include proximal tibial procurvatum, internal tibial torsion, and limb length discrepancy. Compensatory deformities in the distal femur and distal tibia may occur. When non-operative treatment fails the deformities progress through skeletal maturity and can result in pain, gait abnormalities, premature medial compartment knee arthritis, and limb length discrepancy. Surgical options depend on the patient's age, weight, extent of physeal involvement, severity, and number of deformities. They include growth modulation procedures such as guided growth for gradual correction with hemi-epiphysiodesis and physeal closure to prevent recurrence and equalize limb lengths, physeal bar resection, physeal distraction, osteotomies with acute correction and stabilization, gradual correction with multi-planar dynamic external fixation, and various combinations of all modalities. The goals of surgery are to restore normal joint and limb alignment, equalize limb lengths at skeletal maturity, and prevent recurrence. The purpose of this literature review is to delineate basic concepts and reconstructive surgical treatment strategies for patients with Blount's disease.

Gradual correction of proximal tibia deformity for Blount disease in adolescent and young adults

PURPOSE

Management of Blount disease in adolescents and young adults is complex and associated with high risk of morbidities. Gradual correction with external fixator can minimize soft tissue injury and allow subsequent adjustment in degree of correction. This study investigates the surgical outcome and complication rate of gradual correction of neglected Blount disease through single-level extra-articular corticotomy.

METHODS

Patients treated for Blount disease using external fixator from 2002 to 2016 were recruited for the study. We used Ilizarov and Taylor Spatial Frame (TSF) external fixator to perform simultaneous correction of all the metaphyseal deformities without elevating the tibia plateau. Surgical outcome was evaluated using mechanical axis deviation (MAD), tibial femoral angle (TFA), and femoral condyle tibial shaft angle (FCTSA).

RESULTS

A total of 22 patients with 32 tibias have been recruited for the study. The mean MAD improved from 95 ± 51.4 mm to 9.0 ± 37.7 mm (medial to midpoint of the knee), mean TFA improved from 31 ± 15° varus to 2 ± 14° valgus, and mean FCTSA improved from 53 ± 14° to 86 ± 14°. Mean duration of frame application is 9.4 months. Two patients developed pathological fractures over the distracted bones, one developed delayed consolidation and other developed overcorrection.

CONCLUSIONS

Correction of Blount disease can be achieved by gradual correction using Ilizarov or TSF external fixator with low risk of soft tissue complication. Longer duration of frame application should be considered to reduce the risk of pathological fracture or subsequent deformation of the corrected bone.

Do Different Tibial Osteotomy Techniques Affect Sagittal Alignment in Children with Blount Disease?

Objective

To determine the radiographic outcomes following dome or wedge‐shaped proximal tibial osteotomy in the management of infantile Blount disease with a particular interest in sagittal alignment of the knee joint.

Method

Medical records of patients with Langenskiöld stage 2 Blount disease (aged ≤5 years) who underwent surgical correction between January 2005 and November 2019 were retrospectively identified. Patients with metabolic bone disease, bone tumors, prior traumatic fractures, congenital anomalies, inadequate plain films, and incomplete medical documents were excluded. Patient characteristics (e.g. age, gender, and body mass index [BMI]) and surgical characteristics (e.g. side, type of surgery, and follow‐up times) were recorded. Antero–posterior (AP) and lateral knee radiographs were analyzed. Data were categorized by surgical technique as dome‐shaped proximal tibial osteotomy or wedge‐shaped proximal tibial osteotomy. The femorotibial angle (FTA) was used to evaluate the correction angle in varus deformities. Sagittal alignment of the lower limbs using the posterior tibial slope (PTS) angle was measured postoperatively at 3, 6, 12, and 24 months, and at the final follow‐up visit.

Results

The present study included 72 surgeries of 46 patients who had undergone proximal tibial osteotomy. Twenty‐nine (63%) were male. The mean age of patients at the time of surgery was 34.50 months (range, 26–47). The mean weight was 23.11 ± 4.98 kg (mean ± SD); the mean height was 95.33 ± 6.36 cm, and the mean BMI was 25.32 ± 4.36 kg/m². The mean duration of follow up was 4.77 ± 2.78 years. Sixty‐four patients (88.90%) received dome‐shaped proximal osteotomy of the tibia, while 8 (11.10%) received wedge‐shaped proximal osteotomy of the tibia. The average FTA of the total correction measured was 29.32° ± 7.98°. The demographic data of the two groups were not significantly different for gender, age, BMI, side follow‐up times, and the total correction of varus deformities. In the dome‐shaped osteotomy group, the mean correction of the FTA was 29.59° ± 7.45°. The mean degree of the PTS angle was 6.50° at 3 months, 6.38° at 6 months, 5.32° at 12 months, 5.17° at 24 months, and 5.53° at the final follow‐up visit. In the wedge‐shaped proximal tibial osteotomy group, the mean correction of the FTA was 27.25° ± 11.77°. The PTS was 6.00° at 3 months, 7.50° at 6 months, 7.00° at 12 months, 5.40° at 24 months, and 5.57° at the final follow‐up visit. No significant difference was observed in the radiological outcome between surgical techniques.

Conclusion

Dome and wedge‐shaped proximal tibial osteotomies did not demonstrate significant differences in the PTS angle in children with Blount disease.

Treatment of Infantile Blount Disease: An Update

Although the core principles of managing infantile Blount disease generally remain unchanged, treatment modalities have evolved over the years. Consensus has yet to be reached regarding the efficacy of bracing. Children with Blount disease commonly have advanced bone age, which may impact the timing and magnitude of (over) correction of angular deformity. Techniques of growth modulation, based on the tension band principle, continue to gain popularity. Although there are limited reports in the last decade on proximal tibial osteotomy for this developmental disorder, both acute and gradual correction remain viable treatment options in the appropriate setting. In certain older children (>7 y old) with advanced stages of the disease, a medial hemiplateau elevation combined with lateral proximal tibial hemiepiphysiodesis may be needed to address the epiphyseal deformity. Given the possibility of unpredictable proximal tibial physeal activity, all children with Blount disease should be followed at regular intervals till skeletal maturity. To provide sufficient granularity for pooled analyses and help establish evidence-based clinical guidelines, standardization of reporting clinical outcomes among children with Blount disease is encouraged.

Lengthening in Congenital Femoral Deficiency: A Comparison of Circular External Fixation and a Motorized Intramedullary Nail

BACKGROUND

Circular external fixation for limb-lengthening is associated with frequent and numerous complications. Intramedullary lengthening devices represent a potential advance in limb-lengthening. The purpose of this study was to compare the outcomes of femoral lengthening in pediatric patients treated by either circular external fixation or a motorized intramedullary nail.

METHODS

All patients with a diagnosis of congenital femoral deficiency who had undergone femoral lengthening with either circular external fixation or a motorized intramedullary nail were identified. The motorized intramedullary nail (FITBONE) was used with approval of the U.S. Food and Drug Administration on an individual compassionate-use basis.

RESULTS

Fourteen skeletally mature patients underwent fourteen femoral lengthening sessions using circular external fixation, and thirteen patients underwent fifteen lengthening sessions using the motorized nail. The amount lengthened was similar, with a mean of 4.8 cm (range, 1.0 to 7.4 cm) in the circular fixation group and 4.4 cm (range, 1.5 to 7.0 cm) in the motorized nail group. Complications occurred in all lengthening sessions in all fourteen patients managed with the circular external fixation and in 73% of fifteen lengthening sessions in the thirteen patients managed with the motorized nail. The circular external fixation group averaged 2.36 complications per lengthening session compared with 1.2 per session in the motorized nail group. Twenty-nine percent of the circular fixation group failed to achieve a lengthening goal of at least 4 cm compared with 27% of the motorized nail group who failed to reach the goal. Eight patients had undergone eleven femoral lengthening sessions with circular external fixation prior to undergoing ten lengthening sessions by motorized nail. These patients had a comparable rate of complications with both types of lengthening, but the total number of complications averaged 2.6 per lengthening session with circular external fixation compared with 1.6 per lengthening session with the motorized nail.

CONCLUSIONS

A decreased number of complications was noted with use of a motorized intramedullary nail compared with circular external fixation in pediatric patients undergoing femoral lengthening for congenital femoral deficiency.

LEVEL OF EVIDENCE

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