Residual nonunion following vascularised fibular graft treatment for congenital pseudarthrosis of the tibia: a report of two cases

Orthopaedic manifestations of neurofibromatosis type 1: A case report

Neurofibromatosis type 1 (NF1) or von Recklinghausen disease is one of the most common autosomal dominant genetic diseases. It is characterized by ‘café-au-lait’ spots and multiple tumors starting from the central and peripheric nervous system. The diagnosis is determined on two out of seven criteria: i) A total of 6 or more light brown spots larger than 5 mm in diameter (pre-puberty) or 15 mm in diameter (post-puberty); ii) a total of 2 or more neurofibromas or one plexiform neurofibroma; iii) axillary or inguinal freckling; iv) optic glioma; v) a total of 2 or more Lisch nodules; vi) bone abnormalities: tibia pseudarthrosis or dysplasia of the sphenoid wing; and vii) a relative of first degree having an NF1 diagnosis. A total of ~50% of patients have significant musculoskeletal manifestation, with scoliosis and congenital pseudarthrosis of tibia most common. Management of the orthopaedic manifestations of NF1 is often difficult. Due to NF1 influencing multiple organ systems, patients are likely to benefit most from a multidisciplinary treatment strategy.

Prevalence of neurofibromatosis type 1 in congenital pseudarthrosis of the tibia

A strong relationship between congenital pseudarthrosis of the tibia (CPT) and neurofibromatosis type 1 (NF1) has been suggested, but prevalence varies widely throughout the literature and the criteria used for diagnosis are very heterogeneous. Literature focus is mainly on treatment and no specific review on the prevalence of NF1 has been published. Based on our own observations, we hypothesized the prevalence of NF1 in patients with CPT to be higher than what is previously accepted. We conducted a comprehensive literature review on this topic and compared results with our study population. Twenty-one out of twenty-five patients in the study population matched the NIH diagnostic criteria for NF1 (84.0 %, CI95 = 69.6-98.4 %). These results are higher than the prevalence reported in the literature (55.4 %, CI95 = 50.4-60.4 %).

CONCLUSIONS

The prevalence of NF1 in patients with CPT might be higher than what is reported until now because the criteria of NF1 generally appear only after the diagnosis of CPT. We propose a repeat meticulous examination and a multidisciplinary approach with a clinical genetic counseling in all CPT patients.

WHAT IS KNOWN

• Congenital pseudarthrosis of the tibia and neurofibromatosis type 1 are closely related. • Literature focus is mainly on treatment and little epidemiologic research is available. What is New: • Prevalence of neurofibromatosis type 1 in patient with congenital pseudarthrosis of the tibia might be higher than what is reported until now. • A multidisciplinary approach with meticulous clinical examination and genetic counseling might lead to an earlier diagnosis of neurofibromatosis type 1 in patients with congenital pseudarthrosis of the tibia.

Repair of segmental load-bearing bone defect by autologous mesenchymal stem cells and plasma-derived fibrin impregnated ceramic block results in early recovery of limb function

Calcium phosphate-based bone substitutes have not been used to repair load-bearing bone defects due to their weak mechanical property. In this study, we reevaluated the functional outcomes of combining ceramic block with osteogenic-induced mesenchymal stem cells and platelet-rich plasma (TEB) to repair critical-sized segmental tibial defect. Comparisons were made with fresh marrow-impregnated ceramic block (MIC) and partially demineralized allogeneic bone block (ALLO). Six New Zealand White female rabbits were used in each study group and three rabbits with no implants were used as negative controls. By Day 90, 4/6 rabbits in TEB group and 2/6 in ALLO and MIC groups resumed normal gait pattern. Union was achieved significantly faster in TEB group with a radiological score of 4.50 ± 0.78 versus ALLO (1.06 ± 0.32), MIC (1.28 ± 0.24), and negative controls (0). Histologically, TEB group scored the highest percentage of new bone (82% ± 5.1%) compared to ALLO (5% ± 2.5%) and MIC (26% ± 5.2%). Biomechanically, TEB-treated tibiae achieved the highest compressive strength (43.50 ± 12.72 MPa) compared to those treated with ALLO (15.15 ± 3.57 MPa) and MIC (23.28 ± 6.14 MPa). In conclusion, TEB can repair critical-sized segmental load-bearing bone defects and restore limb function.

Secondary Knee Osteoarthritis due to Neurofibromatosis Type 1 Treated with above the Knee Amputation: A Case Report

Background. Neurofibromatosis Type 1 (NF-1) has a variety of associated orthopaedic manifestations that have been previously reported. We report a case of severe, grade 4 knee osteoarthritis (OA) with recurrent subluxation and joint laxity due to multiple extra-articular neurofibromas ultimately treated with Above the Knee Amputation (AKA). Case Description. A 39-year-old man presented with multiple neurofibromas and lymphedema leading to degenerative changes of the knee. Conservative treatment failed due to the severity of the knee degeneration and patient discomfort. Likewise, arthroplasty was not possible due to poor bone quality and joint instability. Therefore, AKA was selected to relieve symptoms and provide functional improvement. six months after the procedure the patient has increased functional capacity for ambulation and activities of daily living, as well as significant decrease in pain and discomfort. Clinical Relevance. Extra-articular neurofibromas causing severe secondary OA in relatively young patients can be functionally improved with AKA and prosthetic device use.

Orthopaedic manifestations of neurofibromatosis type 1

Neurofibromatosis type 1 (NF-1) is an autosomal dominant disease that affects 1 in 3,000 persons worldwide. Café-au-lait macules and peripheral nerve sheath tumors (ie, neurofibromas) are the most commonly recognized manifestations of NF-1. However, NF-1 affects multiple organ systems, and a multidisciplinary approach to treatment is required. Management of the orthopaedic manifestations of NF-1 is often difficult. The most complex manifestations are scoliosis (dystrophic and nondystrophic), congenital pseudarthrosis of the tibia, and problems related to soft-tissue tumors. Metabolic bone disease is common; many patients are frankly osteopenic, which further complicates treatment. Dystrophic scoliosis, which may be caused by either bony dysplasia or intraspinal pathology, is characterized by early presentation and rapid progression. Pseudarthrosis is common even after instrumented fusion. Nondystrophic scoliosis tends to behave like adolescent idiopathic scoliosis, although it may present earlier and is associated with a higher rate of pseudarthrosis. Congenital pseudarthrosis of the tibia is a long-bone dysplasia that afflicts patients with NF-1. Management of this osseous deformity is challenging. Failure to achieve union and refracture are common.

Treatment for large skeletal defects by free vascularized fibular graft combined with locking plate

BACKGROUND

Reconstruction of large skeletal defects secondary to osteomyelitis or open fracture is a challenging problem. The purpose of this study was to evaluate the results of using free vascularized fibular graft (FVFG) combined with locking plate in the treatment of large skeletal defects from open fracture and infection.

METHODS

Ten patients with a mean age of 34 years (ranged 13-57 years) and a mean length of 8.7 cm (range 6-17 cm) skeletal defect were treated with FVFG and locking plate. The mean follow-up time was 26 months.

RESULTS

Grafting union occurred in all patients, with a mean healing time of 4.5 months. No recurrence of osteomyelitis and stress fractures was observed. The mean time to full weight-bearing was 10 months, and all patients were pain-free and able to walk without supportive devices.

CONCLUSIONS

FVFG combined with locking plate is a viable option for the management of large skeletal defects from open fracture and infection.

Long bone reconstruction with vascularized bone grafts

The vascularized fibula may be used for long bone reconstruction reliably and successfully. Since its description by Taylor, the fibula flap has evolved to solve a myriad of long bone reconstructive dilemmas. The flap is used routinely for non-unions, postoncologic resections, and congenital defects. It provides faster and more reliable union than nonvascularized grafts. When constructed in a double-barrel configuration, it offers the ability to bear weight. The vascularized fibula can be used to maintain growth by virtue of transferring the physis. The vascularized fibula is thus both the workhorse and thoroughbred in long bone construction.