Diego Antonioli

New perspectives in rotator cuff tendon regeneration: review of tissue engineered therapies

Tissue engineering may play a major role in the treatment of rotator cuff tendon lesions through replacement of an injured tendon segment. Tendons have very poor spontaneous regenerative capabilities, and despite intensive remodelling, complete regeneration is never achieved and the strength of tendon and ligaments remains as much as 30% lower than normal even months or years following an acute injury. Tendons seem to be the least complex of the connective tissues with respect to their composition and architecture and this leads to the expectation that they would be more amenable to tissue engineered approaches than other tissues. An accurate literature revision was done in order to know the state of the art of tissue engineering therapies in the field of rotator cuff regeneration. The following techniques of tissue engineering were considered: local injection of stem cells or growth factors, gene transfer, in situ tissue engineering and in vitro production of bioengineered tendons to be further transplanted in the lesion site. So far, few experimental or clinical studies have been done on tendon tissue engineering compared to the extensive work on other tissues of orthopaedic interest, such as bone and cartilage. The existing studies are related to the following tissue engineering methodologies: gene transfer, in situ tissue engineering and in vitro production of bioengineered tendons. In our opinion the previously described literature revision showed the necessity for future studies in this area also because of recent advances in biological and bioactive scaffolds.

Development and validation of a HPLC–ES-MS/MS method for the determination of glucosamine in human synovial fluid

A new HPLC method for the determination of glucosamine (2-amino-2-deoxy-D-glucose) in human synovial fluid was developed and validated. Synovial fluid samples were analyzed after a simple protein precipitation step with trichloroacetic acid using a polymer-based amino column with a mobile phase composed of 10 mM ammonium acetate (pH 7.5)-acetonitrile (20:80, v/v) at 0.3 mL/min flow rate. D-[1-13C]glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180-->72 and 181-->73 for glucosamine and internal standard, respectively). The limit of quantification (injected volume=3 microL) was 0.02 ng, corresponding to 10 ng/mL in synovial fluid. Calibration curves obtained using matrix-matched calibration standards and internal standard at 600 ng/mL were linear up to 2000 ng/mL. Precision values (%R.S.D.) were < or = 14% in the entire analytical range. Accuracy (%bias) ranged from -11% to 10%. The recoveries measured at three concentration levels (50, 800, and 1500 ng/mL) were higher than 89%. The method was successfully applied to measure endogenous glucosamine levels in synovial fluid samples collected from patients with knee osteoarthritis and glucosamine levels after oral administration of glucosamine sulfate (DONA) at the dose of 1500 mg/day for 14 consecutive days (steady-state).

Remodelling and overgrowth after conservative treatment for femoral and tibial shaft fractures in children

One thousand nine hundred and eighty-four children who had received conservative treatment for shaft (diaphyseal and metadiaphyseal) fractures of lower limbs (1162 femoral, 822 tibial fractures) at an average age of 8.5 years (range 0–14 years) were reviewed by clinical and radiographic investigations at an average follow-up of 6.6 years (1–15 years). Particularly, two main features were evaluated: remodelling of (angular and rotational) deformities and post-traumatic overgrowth. Mechanisms underlying these processes are discussed, based on a review of the literature, and parameters conditioning their evolution are analysed. Finally, criteria for an acceptable reduction (and limits for residual deformities that may be tolerated) at the time of conservative treatment are proposed.

Surgical treatment of proximal ulna nonunion.

We reviewed our experience in the surgical treatment of 12 cases of proximal ulna nonunion. The primary injuries were 2 fracture-dislocations of the olecranon, 6 Monteggia lesions and 3 isolated fractures of the proximal ulna. According to the type of primary injury and its anatomical site, the nonunions were classified into 2 groups, considering that the nonunions nearest to the humerus-ulna joint present a more disabling clinical profile and are more difficult to treat: group A (6 patients — nonunion within 5 cm from the olecranon tip of the olecranon) and group B (6 patients — nonunion between 5 and 10 cm from the olecranon tip of the olecranon). In all cases, after fibrous callus debridement and bone surface remodelling, fixation was performed with plate and screws and homoplastic cortical bone graft (orthogonal or parallel to the plate) and an intercalary bone cylinder when the bone defect was severe. In 3 patients (group A), where the defect was smaller than 1 cm, fixation of the ulna was combined with a resection of the radial neck. Clinical-radiographic healing was achieved in all patients followed for a mean of 27 months. Complications included a case of nonunion due to failure of the intercalary graft with plate breakage. The patient healed after a new surgery performed with same technique. The score, according to the Broberg-Morrey scoring system, was 78 in group A patients and 93 in group B patients. The use of homoplastic cortical bone graft represents an effective technique to improve the mechanical properties of the fixation and supports biological union, even when the bone defect is severe.

Management of hip contractures and dislocations in arthrogryposis

Arthrogryposis represents a group of heterogeneous disorders, characterized by contractures of multiple joints at birth. Involvement of the hip is very common (55–90% of patients) ranging from soft tissue contractures to subluxation and dislocation. Isolated contracture of the hip can usually be managed conservatively: compensative mechanisms and contractures of other joints should be evaluated before planning surgery. For unilateral dislocations, open reduction is indicated to provide a level pelvis, even though the risk of stiffness, avascular necrosis and redislocation is significant. Indications for surgical reduction of bilateral dislocations are more controversial: an adequate evaluation of ambulatory potential of the child (muscular weakness, involvement of upper extremities, etc.) and of stiffness of the hips is suggested. An extensive and long-lasting programme of bracing, physiotherapy and multiple surgery may lead to some measure of functional ambulation in most cases, but high need for surgery and considerable risk of complications must be considered. This paper summarizes problems and principles of treatment for hip contractures and dislocations in arthrogryposis and provides a review of the current literature.

In Vitro Study of the Inhibition and Induction of Human Cytochromes P450 by Crystalline Glucosamine Sulfate

The induction and inhibition of human hepatic cytochrome P450 (CYP) isoforms by crystalline glucosamine sulfate (CGS) was investigated in vitro. Inhibition of CYP1A2, CYP2E1, CYP2C19, CYP2C9, CYP2D6, and CYP3A4 by CGS was assessed using recombinant human enzymes incubated with CGS (up to 3 mM expressed as free base). Induction of CYP1A2, CYP2B6, CYP2C9, CYP2C19 and CYP3A4 by CGS (0.01, 0.3 and 3 mM) was evaluated in cryopreserved human hepatocytes, by determining CYP mRNA expression using quantitative RT-PCR. CGS produced no inhibition or induction of any the CYP enzymes tested at concentrations hundred folds higher than the steady state peak plasma concentrations (approximately 10 microM) observed in man after therapeutic doses of CGS of 1500 mg once a day. Therefore, no clinically relevant metabolic interactions are expected between CGS and co-administered drugs that are substrates of the CYP enzymes investigated.

Humeral shaft aseptic nonunion: treatment with opposite cortical allograft struts

Plate fixation with cortical allograft struts has been used at our Institute for decades to treat aseptic shaft nonunion. The aim of this study was to assess the results of this technique in humeral nonunion. We retrospectively reviewed 57 consecutive patients with humeral diaphyseal nonunion treated by internal fixation combined with cortical allograft struts in the last 7 years in our Department. The patients were followed-up for a mean of 48 months. We had union in 53 cases out of 57. There were 3 cases of infection out of 15 patients previously treated with an external fixator. In our experience the cortical allograft strut is a well standardised and reproducible technique that enables the treatment of severe atrophic non-union with a relatively low complication rate and quick functional recovery.

Arthroscopic treatment of septic arthritis of the shoulder in a 6-year-old boy

Septic arthritis of the shoulder in children is a rare condition. The diagnosis may present some difficulties and, consequently, appropriate treatment often is delayed. Main sequelae are humeral shortening, joint instability, premature arthritis and limited range of motion. We report a case of septic arthritis of the shoulder in a child who was treated by means of shoulder arthroscopy. A 6-year-old boy presented with a history of fever, pain and functional impairment of the shoulder that were lasting despite having undergone antibiotic therapy for 28 days (amoxicillin per os, and then teicoplanin intravenously combined with meropenem intravenously) and an arthrocentesis (no organisms were identified) in another hospital. Clinical examination (pain, swelling, warmness, functional impairment), laboratory tests (white blood cell count, 6.900/mm(3); C-reactive protein, 6.44 mg/dL; erythrocyte sedimentation rate, 119 mm), and imaging studies (radiographs, ultrasonography, computed tomography scan, magnetic resonance imaging, bone scan) performed in our department suggested the diagnosis of a stage IV (with osseous involvement) septic arthritis. Arthroscopic irrigation, debridement, synoviectomy and shaving of the osteochondral erosions were performed, in association with antibiotic therapy (teicoplanin and ceftriaxone disodium intravenously, and then amoxicillin/clavulanate per os). At 22-month follow-up, the patient was asymptomatic and showed a full range of motion. No limb length-discrepancy was found. Radiographs showed irregular profile of the humeral epiphysis without any physeal disturbances. Arthroscopic treatment for septic arthritis of the shoulder in children, though rarely reported, represents an adequate procedure for cases without bone involvement and may lead to good results, even in stage IV cases. Open arthrotomy should be reserved for cases with concomitant osseous infection after failure of arthroscopic treatment.

Congenital pseudarthrosis of the fibula and valgus deformity of the ankle in young children.

Treatment of cases of congenital pseudarthrosis of the fibula presenting with severe or progressive valgus deformity in early childhood is challenging. The purpose of the study presented was to analyse the deforming mechanisms to get therapeutic recommendations for this condition. A 2.5-year-old child was treated by resection of pseudarthrosis and distal tibiofibular fusion (Langenskiold operation) with autogenous bone grafting, associated with subtalar arthroereisis: progressive correction of the deformity was achieved. A 21-month-old child was treated with resection of pseudarthrosis, homologous bone grafting and fibular osteosynthesis: after failure, Langenskiold operation with autogenous bone grafting was performed and stabilization of the deformity was achieved. In young children with congenital pseudarthrosis of the fibula and valgus deformity, early surgical treatment is advisable: fibular ostheosynthesis has limited indications; distal tibiofibular fusion remains the treatment of choice, providing correction that may exceed the simple stabilization of deformity expected. Radiographic findings lead the authors to suggest that part of the effectiveness of the procedure is due to abnormal growth patterns.

Glucosamine binding to proteins in plasma and synovial fluid and blood cell/plasma partitioning in mouse and man in vitro.

Protein binding of [14C]glucosamine (400, 1000 and 4000 ng/ml) was evaluated in human and mouse plasma and in human synovial fluid. Blood cell/plasma partitioning in human and mouse was also determined. There was no measurable protein binding of [14C]glucosamine. Its association with human and mouse blood cells ranged from 43-47% and from 27-29%, respectively. Therefore, the unbound (pharmacologically active) fraction of glucosamine in plasma and at the site of action (the joint) is the same. Protein binding displacement drug-drug interactions are unlikely during the clinical use of crystalline glucosamine sulfate. No corrections are needed, either for unbound fraction when comparing human and mouse pharmacokinetic data or for blood cell/plasma partitioning to assess glucosamine total blood clearance from plasma data in these two species.