Congenital Pseudarthrosis of the Tibia

Guided Growth to Treat Anterolateral Tibial Bowing Associated with Congenital Pseudarthrosis of the Tibia

BACKGROUND

Anterolateral tibial bowing associated with congenital tibial pseudarthrosis occurs often in patients with neurofibromatosis type 1 and results from the inability of the fractured bone to unite, leading to persistent nonunion, abnormal bone growth, and further bowing of the tibia. Current surgical and nonsurgical approaches demonstrate persistent nonunion or refracture, often resulting in amputation.

METHODS

This report describes the management of 3 patients with anterolateral tibial bowing and NF1 who underwent distal tibia-guided growth.

RESULTS

The patients had an average age of 1.6 years at initial operation, with a total of 3 to 4 surgeries over an average of 2.1 years. The latest follow-up on all patients is included, at a mean of 5.1 years after the initial operation. All 3 patients experienced substantial functional improvement and improved alignment of the mechanical axis of the tibia. One patient has experienced refracture.

CONCLUSIONS

Our study indicates that guided growth can serve as an additional surgical option to improve ALTB and potentially reduce the risk of fracture and pseudarthrosis by restoring normal mechanical alignment.

LEVEL OF EVIDENCE

Level-IV, Case Series.

Preventing of nonunion in congenital pseudarthrosis of the tibia cases of Crawford Type I and II through the use of allograft bypass and a brace: Midterm findings

Background

Congenital pseudarthrosis of the tibia is a limb deformity, which can be distressing for the affected patients and the pediatric orthopedic surgeons involved. We hypothesized that the modified McFarland procedure would avoid fractures and even have a corrective effect on the affected tibia in congenital pseudarthrosis of the tibia patients. Toward this end, we evaluated the midterm results of treating congenital pseudarthrosis of the tibia patients of Crawford Type I and II with allograft bypass combined with long-term bracing.

Methods

This study retrospectively evaluated 7 patients with congenital pseudarthrosis of the tibia who were treated with allograft bypass combined with long-term bracing between 2009 and 2018. The median follow-up was 7.0 years (range 3.8-10.0 years). The medical records and radiographs were reviewed for demographic data, clinical characteristics, outcomes, and complications.

Results

At the time of the last follow-up, all allografts revealed complete consolidation in the patients' tibiae at both ends. All patients presented no functional restriction of the lower limbs and no amputation or non-union has occurred. Most of the obvious deformities of the tibia diaphysis or ankle joint were corrected. Two complications occurred that required successful revision surgery.

Conclusion

In this series of seven congenital pseudarthrosis of the tibia patients, the allograft bypass technique showed satisfactory midterm results and validated our hypothesis. For congenital pseudarthrosis of the tibia patients of Crawford Type I and II, this procedure combined with long-term bracing, which involves the affected leg only, can delay or possibly prevent fractures, decrease tibial malalignment, and preserve leg length.

Level of evidence

level IV.

Congenital Pseudoarthrosis of Tibia With Anterolateral Bowing Treated With Ilizarov Ring Fixator: A Case Report

Congenital pseudarthrosis of the tibia (CPT) is a rare, dysplastic condition that is characterized by a "false joint" in the tibia, leading to potential disability. We present a rare case report of a 12-year-old male from India with a history of neurofibromatosis type 1 (NF1) and anterolateral bowing of the tibia since birth. He sustained a tibial fracture during play. X-ray evaluation confirmed the fracture, and a clinical diagnosis of CPT was established. The treatment involved corticotomy for deformity correction and stabilization using Ilizarov's ring fixation. The procedure was successful, with post-operative radiological evaluations showing significant improvement in the center of rotation of angulation (CORA) from 60° pre-operatively to 25° post-operatively. The patient was discharged with an external fixator and after seven months, transitioned to full weight-bearing ambulation with a specialized brace. The Ilizarov procedure proved to be a safe and effective treatment for CPT, offering benefits such as limb lengthening and ankle stabilization.

Efficacy of the "Eiffel tower" double titanium elastic nailing in combined management of congenital pseudarthrosis of the tibia: preliminary outcomes of 17 cases with review of literature

BACKGROUND

Difficulty in obtaining union, recurrent fractures, and residual deformities remain the problems challenging the management of congenital pseudarthrosis of the tibia (CPT). We applied the "Eiffel Tower" double titanium elastic nails (TENs) in the existing combined approach, which takes advantages of TEN's mechanical stability with the protection against refracture, Ilizarov's high fusion rate with alignment control and the biologic environment provided by bone grafting for bony union. The results of this procedure are presented and discussed.

METHODS

Seventeen patients with CPT treated by combined surgery including pseudarthrosis resection, the "Eiffel Tower" double TENs technique, autogenous iliac bone grafting, and Ilizarov fixation between 2013 and 2019 were retrospectively investigated. Signs of bone union, limb length discrepancy (LLD), rate of refracture, and degree of residual deformities were reviewed. The AOFAS Ankle Hindfoot scale and measurement of ankle motion were used to evaluate ankle function. The mean follow-up time was 40.5 (11 to 91) months.

RESULTS

The mean age at index surgery was 6.2 (2.5 to 15) years. Union of the pseudarthrosis was achieved in 100% of cases. Among them, 15 (88.2%) patients obtained union of the pseudarthrosis on the first attempt (primary union). The average time to primary union was 3.8 (2 to 6) months. The rest 2 cases achieved union after additional surgeries (secondary union). In terms of complications, refracture occurred in 2 patients (11.8%) and 4 patients (23.5%) developed pin infection. The mean limb length discrepancy at the final follow up was 33.4 (6-141) mm. The average AOFAS score improved from 38.2 (27 to 51) pre-operatively to 77 (63 to 87) post-operatively (p < 0.01).

CONCLUSIONS

The "Eiffel Tower" double TENs technique is an ideal intramedullary fixation method in the surgical treatment of CPT. The combination of TENs technique with bone grafting and Ilizarov fixation has the advantages of early bone union, less injury on metaphysis, and early functional recovery.

LEVEL OF EVIDENCE

Level IV.

Congenital pseudoarthrosis of the clavicle: Should we reconsider timing and fixation method?

BACKGROUND

Congenital pseudoarthrosis of the clavicle (CPC) is rare and may require treatment, usually because of an unacceptable appearance or occasionally because of pain in an adolescent patient. Spontaneous union is unknown, and consequently any desired union requires open reduction and bone grafting. Many authors recommend performing the operation at the age of 3-5 years and using different fixation methods. We present our experience with three cases and literature review in an attempt to further elucidate the appropriate timing of the procedure and the fixation method.

METHODS

This was a retrospective review of three cases presenting with pseudoarthrosis of the clavicle. All cases were treated by curettage of the pseudoarthrosis, with the void filled using full-thickness ileac crest autologous bone graft and bridging plate-one compression and two anatomical, at different ages. We performed a literature review with emphasis on timing of the procedure, fixation method and complications.

RESULTS

All patients healed with good callus formation. One patient (5-year-old female treated using a compression plate) experienced overlying skin irritation and underwent removal of the plate. There were no restriction of movement, pain or any other complaint on the final follow-up. We did not find any difference in the operating complexity at different ages, but when a compression plate was used, it had to be removed later due to bulging of the plate.

DISCUSSION

No clinical difference was observed between earlier and late operation. Therefore, we suggest performing a curettage of the pseudoarthrosis, gapping the void using autologous bone graft, and using an anatomical bridging plate.

Identification and characterization of NF1 and non-NF1 congenital pseudarthrosis of the tibia based on germline NF1 variants: genetic and clinical analysis of 75 patients

Background

Congenital pseudarthrosis of the tibia (CPT) is a rare disease. Some patients present neurofibromatosis type 1 (NF1), while some others do not manifest NF1 (non-NF1). The etiology of CPT, particularly non-NF1 CPT, is not well understood. Here we screened germline variants of 75 CPT cases, including 55 NF1 and 20 non-NF1. Clinical data were classified and analyzed based on NF1 gene variations to investigate the genotype-phenotype relations of the two types of patients.

Results

Using whole-exome sequencing and Multiplex Ligation-Dependent Probe Amplification, 44 out of 55 NF1 CPT patients (80.0%) were identified as carrying pathogenic variants of the NF1 gene. Twenty-five variants were novel; 53.5% of variants were de novo, and a higher proportion of their carriers presented bone fractures compared to inherited variant carriers. No NF1 pathogenic variants were found in all 20 non-NF1 patients. Clinical features comparing NF1 CPT to non-NF1 CPT did not show significant differences in bowing or fracture onset, lateralization, tissue pathogenical results, abnormality of the proximal tibial epiphysis, and follow-up tibial union after surgery. A considerably higher proportion of non-NF1 patients have cystic lesion (Crawford type III) and used braces after surgery.

Conclusions

We analyzed a large cohort of non-NF1 and NF1 CPT patients and provided a new perspective for genotype-phenotype features related to germline NF1 variants. Non-NF1 CPT in general had similar clinical features of the tibia as NF1 CPT. Germline NF1 pathogenic variants could differentiate NF1 from non-NF1 CPT but could not explain the CPT heterogeneity of NF1 patients. Our results suggested that non-NF1 CPT was probably not caused by germline NF1 pathogenic variants. In addition to NF1, other genetic variants could also contribute to CPT pathogenesis. Our findings would facilitate the interpretation of NF1 pathogenic variants in CPT genetic counseling.

Supplementary information

The online version of this article (10.1186/s13023-019-1196-0) contains supplementary material, which is available to authorized users.

Amputation Outcomes in Congenital Pseudarthrosis of the Tibia

BACKGROUND

Successful radiographic union in the treatment of congenital pseudarthrosis of the tibia (CPT) may be complicated by persistent pain, recurrent fracture, and poor function necessitating further intervention, including amputation. The long-term functional, radiographic, and clinical outcomes of patients who have undergone amputation as treatment for CPT are unknown.

METHODS

A retrospective study of patients with a diagnosis of CPT secondary to neurofibromatosis and eventual treatment with amputation were included. Clinical and radiographic data, including initial Crawford classification, type of amputation, subsequent operative procedures, and evidence of radiographic healing were collected.

RESULTS

A total of 17 patients with a mean age of 4.5 years (range, 0.7 to 9.2 y) at the time of amputation met inclusion criteria. Clinical follow-up averaged 11.1 years (range, 2.1 to 18.4 y), with radiographic follow-up averaging 9.1 years (range, 2.1 to 16.4 y). The mean number of surgeries before amputation was 2.2 procedures. Four patients underwent amputation as the primary procedure (3 Boyd, 1 below knee amputation (BKA)). At the time of amputation, a Boyd amputation was performed in 13 patients with stabilization of the pseudoarthrosis achieved with retrograde Rush rodding of the tibia and local autograft. A transtibial amputation (BKA) was performed in 4.After the Boyd procedure, 4 of the 13 patients (31%) demonstrated persistent nonunion of the pseudoarthrosis and required secondary procedures to gain union. At the most recent follow-up, 12 of 13 patients demonstrated successful radiographic healing of the pseudoarthrosis. Two patients, one for persistent pain and the other for refracture, were later converted to a BKA during the late teen years. All patients functioned well with the use of prosthetic devices.

CONCLUSIONS

Union of the pseudoarthrosis occurred in >90% of cases following amputation. However, secondary procedures were required in 13 of the 17 patients (76%). Early amputation in the treatment of CPT provides a stable extremity and potential for a high level of function with the use of an adequate prosthesis.

LEVEL OF EVIDENCE

Level IV-case series.