This case highlights the close association between osteo-fibrous dysplasia (OFD) and adamantinoma, drawing attention to the role for more radical treatment options when treating OFD. We discuss the advancements in joint-sparing endoprostheses using bicortical fixation. Finally we describe a unique biomedical design allowing for manufacture of an
Trabecular bone is a multiscale hierarchical composite material that is known to display time-dependant properties. However, most biomechanical models treat this material as time independent. Time-dependant properties, such as creep and relaxation, are thought to play an important role in many clinically relevant orthopaedic issues: implant loosening, vertebral collapse, and non-traumatic fractures. In this study compressive multiple-load-creep-unload-recovery (MLCUR) tests were applied to human trabecular bone specimens. 15 female femoral heads were harvested, with full ethical approval and patient consent, at the time of total hip replacement. Central cores were extracted and cut parallel under constant irrigation. Specimens were embedded in
We report a case which highlights the progression of osteofibrous dysplasia to adamantinoma and questions whether intralesional curettage is the appropriate treatment. The role of a joint-sparing massive endoprosthesis using cortical fixation is demonstrated and we describe a unique biomedical design which resulted in the manufacture of an
This chamber is designed for use with conscious or unconscious patients requiring treatment with oxygen under high pressure. It can be pressurised to a maximum of 45 pounds per square inch above ambient (60 pounds per square inch absolute). The unit consists of two parts, the pressure chamber and the control console, connected together by flexible hose. The chamber can be operated up to a distance of 100 feet from the control console and both parts are mobile. The chamber consists of two concentrically mounted transparent cylinders, closed at the ends by domed metal
Intramedullary nailing is acknowledged as a safe and effective mode of treatment for many tibial fractures. Implant removal is frequently indicated either as an elective procedure following union or because of problems such as infection or delayed fracture union. It is therefore essential that intramedullary rod removal should be reasonably straightforward and atraumatic. We describe three cases in which bony growth into the implant has made rod removal either difficult or impossible. We include photographs of two removed implants with clearly visible areas of osseo-integration with bony growth into the cannulation through the interlocking holes as well as radiographs demonstrating the same phenomenon. The average time between insertion and removal was 16 months. In all cases an
Introduction and Aims: A retrospective review of the medical records and radiographs of patients treated with operative fixation of two-part proximal humerus fractures was undertaken to compare the results of different modes of fixation. Comparison was made between ORIF with a blade plate, percutaneous Kirschner wire fixation, and intramedullary nail fixation utilising a Polarus nail. Method: Thirty-six patients were treated with intramedullary fixation, 11 with blade plate fixation and 10 with percutaneous fixation, utilising Kirschner wires. Union rates were 34/36 (94%) for the Polarus nail, 9/10 (90%) for K-wire fixation and 9/11 (82%) for blade plate fixation. Time to union averaged 12.4 weeks for the Polarus nail, 11 weeks for K-wire fixation and 21 weeks for blade plate fixation. Average active shoulder range of motion in forward flexion/abduction were 125/118 degrees for intramedullary nail, 132/132 degrees for the blade plate and 112/111 degrees for patients treated with K-wire fixation. Results: The major discrepancy in comparison of the different modes of fixation was in the complication rate. Ten complications occurred in the group treated with intramedullary fixation. These included one non-union, one painless fibrous non-union and back out of the proximal interlocking screw in eight patients, five of which required screw removal. Seven of 11 patients treated with blade plate fixation experienced complications, including two non-unions, two malunions, two with functionally limiting heterotopic ossification, one arthrofibrosis and one with persistent pain. The complications associated with percutaneous Kirschner wire fixation included one non-union, two malunions, four developed functionally limiting heterotopic ossification, five incidences of early pin removal secondary to pin migration, one arthrofibrosis requiring surgical intervention and one infection requiring surgical irrigation and debridement. Conclusion: Results comparable in all groups. Fewer complications seen with intramedullary fixation. Majority of complications with Polarus nail related to backing out of proximal interlocking screw. Modification of implant to include
The aim of this study was to compare the cost-effectiveness of
intramedullary nail fixation and ‘locking’ plate fixation in the
treatment of extra-articular fractures of the distal tibia. An economic evaluation was conducted from the perspective of
the United Kingdom National Health Service (NHS) and personal social
services (PSS), based on evidence from the Fixation of Distal Tibia
Fractures (UK FixDT) multicentre parallel trial. Data from 321 patients
were available for analysis. Costs were collected prospectively
over the 12-month follow-up period using trial case report forms
and participant-completed questionnaires. Cost-effectiveness was
reported in terms of incremental cost per quality adjusted life
year (QALY) gained, and net monetary benefit. Sensitivity analyses
were conducted to test the robustness of cost-effectiveness estimates.Aim
Patients and Methods
Conventional methods of treating ankle fractures
in the elderly are associated with high rates of complication. We describe
the results of treating these injuries in 48 frail elderly patients
with a long calcaneotalotibial nail. The mean age of the group was 82 years (61 to 96) and 41 (85%)
were women. All were frail, with multiple medical comorbidities
and their mean American Society of Anaesthesiologists score was
3 (3 to 4). None could walk independently before their operation.
All the fractures were displaced and unstable; the majority (94%,
45 of 48) were low-energy injuries and 40% (19 of 48) were open. The overall mortality at six months was 35%. Of the surviving
patients, 90% returned to their pre-injury level of function. The
mean pre- and post-operative Olerud and Molander questionnaire scores
were 62 and 57 respectively. Complications included superficial
infection (4%, two of 48); deep infection (2%, one of 48); a broken
or loose distal locking screw (6%, three of 48); valgus malunion
(4%, two of 48); and one below-knee amputation following an unsuccessful
vascular operation. There were no cases of nonunion, nail breakage
or peri-prosthetic fracture. A calcaneotalotibial nail is an excellent device for treating
an unstable fracture of the ankle in the frail elderly patient.
It allows the patient to mobilise immediately and minimises the
risk of bone or wound problems. A long nail which crosses the isthmus
of the tibia avoids the risk of peri-prosthetic fracture associated
with shorter devices. Cite this article:
This review is aimed at clinicians appraising
preclinical trauma studies and researchers investigating compromised bone
healing or novel treatments for fractures. It categorises the clinical
scenarios of poor healing of fractures and attempts to match them
with the appropriate animal models in the literature. We performed an extensive literature search of animal models
of long bone fracture repair/nonunion and grouped the resulting
studies according to the clinical scenario they were attempting
to reflect; we then scrutinised them for their reliability and accuracy
in reproducing that clinical scenario. Models for normal fracture repair (primary and secondary), delayed
union, nonunion (atrophic and hypertrophic), segmental defects and
fractures at risk of impaired healing were identified. Their accuracy
in reflecting the clinical scenario ranged greatly and the reliability
of reproducing the scenario ranged from 100% to 40%. It is vital to know the limitations and success of each model
when considering its application.
This paper describes the preliminary results of a proximal tibial endoprosthesis which spares the knee joint and enables retention of the natural articulation by replacing part of the tibial metaphysis and diaphysis. In eight patients who had a primary malignant bone tumour of the proximal tibia, the distal stem, which had a hydroxyapatite-coated collar to improve fixation, was cemented into the medullary canal. The proximal end had hydroxyapatite-coated extracortical plates which were secured to the remaining proximal tibial metaphysis using cortical screws. The mean age of the patients at operation was 28.9 years (8 to 43) and the mean follow-up was for 35 months (4 to 48). The mean Musculoskeletal Tumour Society score was 79% (57% to 90%), the mean Oxford Knee score was 40 points of 48 (36 to 46) and the mean knee flexion was 112° (100° to 120°). In one patient, revision to a below-knee amputation through the prosthesis was required because of recurrence of the tumour. Another patient sustained a periprosthetic fracture which healed with a painful malunion. This was revised to a further endoprosthesis which replaced the knee. In the remaining six patients the prosthesis allowed preservation of the knee joint with good function and no early evidence of loosening. Further follow-up is required to assess the longevity of these prostheses.
Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant. Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1–34) 5 μg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters. These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.
An understanding of the remodelling of tendon is crucial for the development of scientific methods of treatment and rehabilitation. This study tested the hypothesis that tendon adapts structurally in response to changes in functional loading. A novel model allowed manipulation of the mechanical environment of the patellar tendon in the presence of normal joint movement via the application of an adjustable external fixator mechanism between the patella and the tibia in sheep, while avoiding exposure of the patellar tendon itself. Stress shielding caused a significant reduction in the structural and material properties of stiffness (79%), ultimate load (69%), energy absorbed (61%), elastic modulus (76%) and ultimate stress (72%) of the tendon compared with controls. Compared with the material properties the structural properties exhibited better recovery after re-stressing with stiffness 97%, ultimate load 92%, energy absorbed 96%, elastic modulus 79% and ultimate stress 80%. The cross-sectional area of the re-stressed tendons was significantly greater than that of stress-shielded tendons. The remodelling phenomena exhibited in this study are consistent with a putative feedback mechanism under strain control. This study provides a basis from which to explore the interactions of tendon remodelling and mechanical environment.
Fragility fractures of the ankle occur mainly in elderly osteoporotic women. They are inherently unstable and difficult to manage. There is a high incidence of complications with both non-operative and operative treatment. We treated 12 such fractures by closed reduction and stabilisation using a retrograde calcaneotalotibial expandable nail. The mean age of patients was 84 years (75 to 95). All were women and were able to walk fully weight-bearing after surgery. There were no wound complications. One patient died from a myocardial infarction 24 days after surgery. The 11 other patients were followed up for a mean of 67 weeks (39 to 104). All the fractures maintained satisfactory alignment and healed without delay. Six patients refused removal of the nail after union of the fracture. The functional rating using the scale of Olerud and Molander gave a mean score at follow-up of 61, compared with a pre-injury value of 70.