CPT is a uniquely difficult condition, often associated with Neurofibromatosis (NF1), where bone healing is compromised. Although rare, the severity of this condition and the multiple procedures often entailed in treating it, warrant research attention. As study material is limited, animal models of the disorder are desirable for testing new treatments.

We sought to create a model of CPT where both copies of the NF1 gene were ablated at the fracture site, as has been found in some clinical specimens. NF1 floxed mice had fracture surgery; both closed fracture and open osteotomy were performed. Either a Cre- or control GFP-adenovirus was injected into the fracture site at day zero. Recombination was confirmed in ZAP reporter mice. Additionally, cell culture studies were used to examine the possible responses of NF1+/+ (wild type) NF1+/− or NF1−/− to drugs which may rescue the dysregulated Ras/MAPK pathway in NF1.

In closed fractures, radiographic bridging was 100% in NF1+/+ calluses and <40% in NF1−/− calluses (P<0.05). In open fractures, radiographic bridging was 75% in NF1+/+ calluses and <30% in NF1−/− calluses (P<0.05). In both fracture repair models the NF1−/− state was associated with a significant up to 15-fold increase in fibrotic tissue invading the callus by week 3. In NF1−/− fractures, large numbers of TRAP+ cells were observed histologically in the fibrotic tissue. Closed fractures also showed a significant increase in BRDU labelled proliferating cells in the callus. In cell culture models of NF1 deficient osteogenesis, NF1−/− progenitors were found to be significantly impaired in their capacity to form a calcified matrix as measured by Alizarin Red S staining and osteogenic markers (Runx2, Osteocalcin, Alp expression). However, when differentiated calvarial NF1 floxed osteoblasts were treated with Cre adenovirus, mineralization was not affected, suggesting that NF1 impacts on osteogenic differentiation rather than mature cell function. Treatment with MEK inhibitor PD0325901 was found to rescue the NF1−/− progenitor differentiation phenotype and permit robust mineralization. Treatment with the JNK inhibitor SP600125 was also able to improve ALP activity and mineralization in NF1+/− osteoprogenitors compared to control cells.

This model of NF1 −/− induction at a fracture or osteotomy site closely replicates the clinical condition of CPT, with lack of bone healing and fibrous tissue invasion. Underlying defects in bone cell differentiation in NF1 deficiencies can be at least partially rescued by JNK and MEK inhibitors.

The problem of retained drain fragments is a well known but under reported complication in the literature.

The authors present the case of a 66 years old male, who suffered a right distal humerus fracture luxation six years ago that was treated conservatively. He went to the emergency service with fever and right elbow purulent drainage.

Physical examination showed deformity, swelling and fluctuation of the right elbow with purulent drainage through cutaneous fistula. The x-ray showed instable inveterate pseudarthrosis of the distal humerus. Leucocytosis and neutrophylia with increased CRP were presente in the blood tests and the patient started empiric treatment with Ceftiaxone IV. A MRSA was isolated in cultural exam of the exsudate, and a six weeks treatment with Vancomycin IV was iniciated.

Exhaustive surgical cleaning was performed and two plastic foreing bodies (fragmented drains) were removed.

At the time of discharge the patient was afebrile, with normal analytical parameters and negative culture tests.

The orthopaedic surgeon should considerate the presence of a foreign body in patients with infected abcess and traumatic or surgery previous history.

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Aim

To determine the preferable treatment for congenital pseudarthrosis of the tibia, we retrospectively reviewed 19 patients (20 limbs) treated consecutively over a 22 year period (1988–2007). Fifteen were followed up to maturity. The patients were assessed for union, leg length discrepancy (LLD), ankle valgus, range of ankle movement and distal tibial physeal injury.

It is generally accepted that children treated for congenital pseudarthrosis of the tibia (CPT) should be followed-up until skeletal maturity, before drawing conclusions about the efficacy of treatment. We undertook this study in order to evaluate the long-term results of treatment of CPT by excision of the pseudarthrosis, intramedullary rodding and onlay cortical bone grafting.

Among a total of 46 children with CPT treated by a single surgeon during a 20-year period, 38 had been treated by this technique and 11 of these children have reached skeletal maturity. These eleven cases (nine boys and two girls) formed the basis for this study.

The mean age at presentation was 3.1 years (range 0.4–7 years); the mean age at index surgery was 3.2 years (range 0.7–7 years). The mean age at follow-up was 18.4 years (range 16–21.6 years) with a mean interval between surgery and final follow-up of 15.2 years (range 12.8–17.4 years).

In all 11 children bone graft was harvested from the contralateral tibial diaphysis. Rods passed from the heel were used in nine children and in two Sheffield telescopic rods were passed from the ankle into the tibia. The fibula was divided in three children to ensure that the tibial fragments were in good contact before placing the graft astride them; the fibula was not touched in the remaining eight instances. To ensure that the intramedullary rod supported the pseudarthrosis site till skeletal maturity, revision rodding was performed as needed when the tip of the rod receded into the distal third. A thermoplastic clamshell orthosis was used till skeletal maturity.

At final follow-up the union at the pseudarthrosis site was deemed to be ‘sound’ only if two independent observers concurred that there was definite bony continuity of the cortices on both the anteroposterior and lateral radiographs. Deformities of the tibia and ankle and ranges of motion of the knee, ankle and subtalar joints were noted. The limb lengths were measured with scanograms. The morbidity at the bone graft donor site was recorded. The function of the ankle was assessed by applying the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hind foot Score.

Primary union of the tibial pseudarthrosis was achieved in nine of 11 cases with a mean time to union of 6.1 months. Secondary union was achieved in the remaining two cases following further intervention. At final follow-up sound union of the tibial pseudarthrosis was noted in all eleven patients but persistent pseudarthrosis of the fibula was present in 10 of 11 cases. The lateral malleolus was proximally situated in six cases.

Ten of eleven children underwent a total of 21 secondary operations on an average of 2.6 years (range 0.5–5.1 years) after initial union was achieved. Six re-fractures were encountered in five patients at a mean of 6.1 years after index surgery. All the re-fractures united following the single episode of intervention. The overall mean shortening at final follow-up was 2.6 cm. At final follow-up, five patients had ankle valgus greater than 10 degrees. All the 11 patients walked without pain. Only two patients had significant motion at the ankle. Despite the ankle stiffness in the remaining children the AOFAS ankle-hindfoot scores ranged between 70 and 98 (mean 83.3).

Our long-term results are comparable to the results of other studies in terms of the rate of union, the re-fracture rate, limb length discrepancy, residual deformity and the frequency of surgery.

Re-positioning osteotomy in the treatment of un-united fracture neck of femur in young patients improves the biomechanical pre-conditions to promote bone union of the Pseudarthrosis. This operative procedure is the method of choice for Pseudarthrosis of the neck of the femur with a viable femoral head. It is also the method of choice in children and in adolescents even if there is avascular necrosis of the femoral head. The operative technique permits exacts planning, stable osteosynthesis both of the un-united fracture of the neck of the femur as well as the osteotomy and allows early mobilisation. In this series of 56 cases, only six (10%) had collapse of the femoral head due to avascular necrosis, six (10%) patients had severe pain in the hip and nine (16%) patients had severe restriction of hip movement. The overall success of the operation in this series was 84%

We have prospectively studied the outcome of infections associated with implants which were retained and treated using a standardised antimicrobial protocol. Over a period of four years, we studied 24 consecutive patients who had symptoms of infection for less than one year, a stable implant, no sinus tract and a known pathogen which was susceptible to recommended antimicrobial agents. The infections involved hip prostheses (14), knee prostheses (5), an internal fixation device (4), and an ankle prosthesis (1).

Twenty patients had a successful outcome at a median follow-up of 3.7 years (1.8 to 4.7); four had failure of the implant after a median follow-up of 1.2 years (0.3 to 2.5). The probability of survival without failure of treatment was 96% at one year (95% confidence interval (CI) 88 to 100), 92% at two years (95% CI 80 to 100) and 86% at three years (95% CI 72 to 100).

Patients with a short-term infection but with a stable implant, no sinus tract and a known pathogen may be successfully treated by retention of the implant and the use of a standardised regimen of antimicrobial treatment.