Segmental composite porous scaffolds with either osteogenesis or anti-bone resorption properties tested in a rabbit ulna defect model.

A functional biomaterial with a therapeutic effect is desirable as an adjuvant therapy to enhance bone formation and prevent local recurrence of bone tumours, especially when the resection margins are not identifiable. In this study, novel composite materials were developed with dual properties of osteopromotion and bone resorption to mimic the tumour inhibition effect, including water-soluble phosphorylated chitosan (P-chitosan) for increasing osteoblasts activity and disodium (1 → 4)-2-deoxy-2-sulphoamino-ß-d-glucopyranuronan (S-chitosan) for inhibiting bone resorption activity. First, P-chitosan and S-chitosan were respectively incorporated into two kinds of PLGA/TCP-based scaffold, i.e. PLGA-TCP-P-chitosan (P/T/P-chitosan) and PLGA-TCP-S-chitosan (P/T/S-chitosan) scaffolds. We subsequently tested combined scaffolds of PLGA-TCP-P-S-P-chitosan (P/T/PSP-chitosan) made of P/T/P-chitosan and P/T/S-chitosan to assess their integral effect, on enhancement of bone formation with P/T/P-chitosan and inhibition of tissue regeneration with P/T/S-chitosan, in an established rabbit ulnar bone defect model to imitate bone resection post-bone tumour. To compare bone healing in the defects, the P/T/P-chitosan group was regarded as a bone formation enhancement group, while the P/T group served as a control. Bone mineral density (BMD) in the P/T/P-chitosan and P/T/PSP-chitosan groups were found to be significantly higher than those in the P/T group, while that in the P/T/P-chitosan group was greater than that in the P/T/PSP-chitosan group (p < 0.05). These findings demonstrated that P/T/PSP-chitosan scaffolds possessed more osteogenic potential than the P/T scaffold but less osteogenic effect than the P/T/P-chitosan scaffold, as the S-chitosan component inhibited the activities of osteoblasts for bone formation. These findings implied a dual function of the designed P/T/PSP-chitosan for further preclinical validation and potential applications in the prevention of local recurrence and for enhancing bone repair after bone tumour resection. Copyright © 2013 John Wiley & Sons, Ltd.

Superimposed electrical stimulation improves mobility of pre-stiff thumbs after ulnar collateral ligament injury of the metacarpophalangeal joint: a randomized study.

OBJECTIVE: This study aimed at testing the ability of the superimposed electrical stimulation technique to restore the mobility of pre-stiff thumbs after operative repair for rupture of the ulnar collateral ligament. MATERIAL AND METHODS: Eight patients demonstrating a pre-stiff metacarpophalangeal joint were involved in two rehabilitation sessions of a counterbalanced design. In the voluntary contraction session, they performed 20min of repeated active flexions of the impaired metacarpophalangeal joint. In the superimposed electrical stimulation session, they performed 20min of percutaneous neuromuscular electrical stimulations which were superimposed to voluntary flexion. RESULTS: Mean active range of motion improvement from pre- to post-session was significantly greater in the superimposed electrical stimulation condition compared to the voluntary contraction condition (11±5 deg versus 3±4 deg; P<0.01). CONCLUSION: Superimposing electrical stimulation to voluntary contractions is an efficient technique to improve active range of motion of the pre-stiff metacarpophalangeal joint of the thumb.

Results of single-staged rotational osteotomy in a child with congenital proximal radioulnar synostosis: subjective and objective evaluation.

BACKGROUND: For congenital proximal radioulnar synostosis, both conservative and operative treatments have been described. Most of the studies describing surgical interventions are based on subjective evaluation of the forearm function and have used severe degree of forearm pronation as an indication for surgery. This study describes a single-staged rotational osteotomy of the proximal third ulna and distal third radius. The aim of the study was to assess the utility of the described surgical procedure by subjective and objective evaluations of the forearm function. METHODS: Forty-eight children with congenital proximal radioulnar synostosis were evaluated by subjective and objective assessments and were followed up prospectively. Subjective evaluation consisted of a set of 12 questions regarding the basic activities of life. Objective evaluation was made using the Jebsen-Taylor hand-function test and a classification system used by Failla and colleagues for 15 tasks described by Morrey and colleagues. Eleven children were treated conservatively. Thirty-six children underwent a single-staged rotational osteotomy of the proximal third ulna and distal third radius. After surgery, the evaluations were repeated. The mean age at surgery was 8.6±3.7 years, and the mean postoperative follow-up period was 54±13 months. RESULTS: All operated forearms showed a statistically significant improvement in functioning after surgery as per the subjective and objective evaluations. The mean time taken to carry out all activities before surgery was 47.7+10.0 seconds, which significantly reduced to 33.3+6.6 seconds after surgery (P=0.0001) as per the results of the Jebsen-Taylor hand-function test. All good (n=19) and fair (n=11) results were converted to excellent (n=30) after surgery as per the modified Failla classification. There were no neurovascular injuries as compared with other published techniques. Only 1 child had delayed union, and 1 had persistent dorsal angulation at the radial osteotomy site. CONCLUSIONS: For patients with congenital radioulnar synostosis and pronation deformity interfering with function and quality of life, the single-staged rotational osteotomy of the radius and ulna is a good alternative procedure. LEVEL OF EVIDENCE: Level IV--therapeutic.

[Manipulative reduction and splint fixation for the treatment of middle and lower segment fracture of ulnar and radius].

OBJECTIVE: To investigate the outcome of manipulative reduction and splint fixation for treatment of middle and lower fractures of ulnar and radius. METHODS: Sixty-eight patients with lower segment fractures of ulnar and radius included 46 male and 22 female, aged from 1 to 26 years. The course was from 10 min to 1 week. There were 39 cases in right and 29 in left; 45 in inferior segment and 23 in middle segment. All cases were closed fractures. According to fracture displacement, different methods of manipulation and splint or plaster splint fixation were used to reduction and fixation. RESULTS: Sixty-eight patient were followed-up for 0.5 to 1 year (mean 8 months), the fractures were all healing. According to the effective evaluation criteria, the results were excellent in 57 cases, good in 11. X-ray film showed anatomic reduction in 38 cases, similar to anatomic reduction in 20, functional reduction in 10. CONCLUSIONS: Manipulative reduction and splint fixation for the treatment of the ulnar and radial bone fractures is a method of simple, minimally invasive, effective and functional advantages of quick recovery.

Bovine bone implant with bovine bone morphogenetic protein in healing a canine ulnar defect.

Xenograft is considered an alternative material for bone transplantation, but its bone healing capacity is inferior compared to that of autografts and allografts. Here, we tested whether bone morphogenetic protein (BMP) addition enhances the suitability of demineralized xenogeneic bovine bone for bone grafting in dogs, and whether xenogeneic bone is a suitable carrier material for BMPs. The capacity of demineralized bovine bone implants, with and without native partially purified bovine BMP, to heal a 2-cm ulnar defect was determined in six dogs over a follow-up time of 20 weeks. No instances of bone union were seen, but there was slightly more bone formation in the xenografts with BMP, though the difference was not statistically significant. The ulnas treated with an implant with BMP were also mechanically stronger, but the difference was not significant. Computed tomography scans showed no differences in the implant area in bone density, bone mineral content, or bone cross-sectional area. It is concluded that native, partially purified BMP does not sufficiently improve the suitability of bovine demineralized xenografts as a bone substitute material for dog. Demineralized xenogeneic bone does not seem to be a feasible carrier material for BMP.

Prevention of osteoporosis by pulsed electromagnetic fields.

Using an animal model, we examined the use of pulsed electromagnetic fields, induced at a physiological frequency and intensity, to prevent the osteoporosis that is concomitant with disuse. By protecting the left ulnae of turkeys from functional loading, we noted a loss of bone of 13.0 per cent compared with the intact contralateral control ulnae over an eight-week experimental period. Using a treatment regimen of one hour per day of pulsed electromagnetic fields, we observed an osteogenic dose-response to induced electrical power, with a maximum osteogenic effect between 0.01 and 0.04 tesla per second. Pulse power levels of more or less than these levels were less effective. The maximum osteogenic response was obtained by a decrease in the level of intracortical remodeling, inhibition of endosteal resorption, and stimulation of both periosteal and endosteal new-bone formation. These data suggest that short daily periods of exposure to appropriate electromagnetic fields can beneficially influence the behavior of the cell populations that are responsible for bone-remodeling, and that there is an effective window of induced electrical power in which bone mass can be controlled in the absence of mechanical loading.

The use of demineralized bone matrix in the repair of segmental defects. Augmentation with extracted matrix proteins and a comparison with autologous grafts.

A soluble protein component of bone, bone morphogenetic protein, and decalcified bone matrix have been shown to induce the formation of bone in extraosseous tissue. Clinical and animal studies investigating the use of these materials as bone grafts have shown radiographic and histological evidence of formation of bone, but the clinical usefulness of these grafts remains unknown. This study compared the healing processes when plasma-coated demineralized bone matrix and autologous cancellous bone were used to graft segmental defects of bone. A standard procedure was used to make a two-centimeter defect bilaterally in the ulna of forty-eight skeletally mature New Zealand White rabbits. In each rabbit, one ulnar defect was grafted with autologous citrated plasma-coated demineralized bone matrix while the other defect served as a control and was grafted with either autologous cancellous bone from the iliac crest, demineralized bone matrix, or demineralized bone matrix augmented with bone proteins that had been extracted with guanidinium hydrochloride. The ulnar defect was stabilized by the intact radius, and no supplemental device was necessary for fixation. To examine spontaneous healing in this model, one group of rabbits had a control defect that was not grafted. The grafts were periodically evaluated by radiographs, and twelve weeks after surgery the grafts were harvested and tested to failure in a standard torsion-test machine. The mechanical parameters were calculated, and histological examination of major fragments of the grafts was performed. The results of the radiographic and histological evaluation showed that all of the grafted ulnae healed, with fusion of the graft to the cut ends of the defect and reformation of approximately normal anatomy. No ungrafted ulnar defects healed. The results from the mechanical tests were evaluated by comparing the defect that was grafted with plasma-coated demineralized bone matrix with the control graft in each animal. These data showed that: twelve weeks after grafting, the normal ulnae were significantly stronger than the ulnae that had been grafted with plasma-coated demineralized bone matrix; the ulnae that had been grafted with plasma-coated demineralized bone matrix and those that had been grafted with autologous bone were equivalent in strength; and twelve weeks after grafting, grafts of demineralized bone matrix that were augmented with extracted bone proteins were significantly stronger than those that had not been so augmented.

Silicone implants.

Infection has not been considered in this article with each individual implant. The incidence is low indeed. In the only publication concerned primarily with the topic of infection following silicone implant surgery, Millender et al. reviewed 2105 implants of varying kinds. There were ten infections, seven of which were with Staphylococcus aureus. The onset was remarkably late--17 days after surgery on average. In seven cases the implant had to be removed and the eventual result was good, being likened to that obtained after an excisional arthroplasty. Reviewing the complications that occur with the various implants, it becomes evident that there are three primary concerns--fracture, subluxation, and synovitis. Fracture occurs primarily in the wrist and the metacarpophalangeal implants. The incidence of fracture in the wrist implant is 8.6, 9.4, and 19.8 per cent, giving an average of the means of 12.6 per cent. In the metacarpophalangeal joint, the incidence with the Swanson design is variously 1.9, 26.2 and 21 per cent, the average of the means being 16.4 per cent. The Niebauer design is reported as having a fracture rate of 29.7 and 38 per cent, for an average of the means of 33.9 per cent. The somewhat lower incidence of fracture of the wrist implant is offset by the fact that, in contrast to the situation with the smaller joint, the fracture is almost always symptomatic, requiring treatment. Largely for this reason, silicone wrist arthroplasty is limited mainly to the rheumatoid patient, being little used for post-traumatic arthritis. Subluxation of implants occurs mainly with the carpal replacements. The incidence in independent reports are 56.5 and 50 per cent, for an average of the means of 53.3 per cent with the scaphoid; 20, 20, and 50 per cent for an average of the means of 30 per cent with the lunate; and 5.3, 10, 11.2, 29, and 32 per cent for an average of the means of 17.5 per cent with the trapezium. In the case of the trapezium, excision of a portion of the trapezoid, supplemented where necessary by ligament reconstruction to support the first metacarpal, appears to give the hope of lowering the incidence of subluxation to an acceptable level. With the lunate, preservation of an anterior shell may give satisfactory results but judgment should await longer term studies of larger groups. The scaphoid implant gives most cause for concern, both because the incidence is high and because the solutions offered have either failed or are too recent to judge and perhaps too radical to accept.(ABSTRACT TRUNCATED AT 400 WORDS)