The objective of this study was to determine if a synthetic bone
substitute would provide results similar to bone from osteoporotic
femoral heads during Pushout studies were performed with the dynamic hip screw (DHS)
and the DHS Blade in both cadaveric femoral heads and artificial
bone substitutes in the form of polyurethane foam blocks of different
density. The pushout studies were performed as a means of comparing
the force displacement curves produced by each implant within each
material.Introduction
Methods
We analysed the morbidity, mortality and outcome of cervical spine injuries in patients over the age of 65 years in a retrospective review of 107 elderly patients admitted to our tertiary referral spinal injuries unit with cervical spine injuries between 1994 and 2002. The data were acquired by analysis of the national spinal unit database, hospital inpatient enquiry (HIPE) system, chart and radiographic review. Mean age was 74 years (range 66-93yrs). The male to female ratio was 2.1: 1(M=72, F=35). The mean follow-up was 4.4 years (1-9 years) and mean in-hospital stay was 10 days. The mechanism of injury was a fall in 75 and a road traffic accident (RTA) in the remaining 32 patients. The overall complication rate was 18.6% with an associated in-hospital mortality of 11.2%. Outcome was assessed using the Cervical Spine Outcomes Questionnaire (CSOQ) from Johns Hopkins School of Medicine. Functional outcome scores approached pre-morbid level in almost all patients. Functional disability was more marked in the patients with neurological deficit at the time of injury. Outcome of the injury is related to the increasing age, co-morbidity and the severity of the neurological deficit. Injuries of the cervical spine are a not infrequent occurrence in the elderly and occur with relatively minor trauma. Neck pain in the elderly patient should be thoroughly evaluated to exclude C2 injuries. Most patients can be managed in an orthosis but unstable injuries require rigid external immobilisation.
We biomechanically investigated whether the standard dynamic hip screw (DHS) or the DHS blade achieves better fixation in bone with regard to resistance to pushout, pullout and torsional stability. The experiments were undertaken in an artificial bone substrate in the form of polyurethane foam blocks with predefined mechanical properties. Pushout tests were also repeated in cadaveric femoral heads. The results showed that the DHS blade outperformed the DHS with regard to the two most important characteristics of implant fixation, namely resistance to pushout and rotational stability. We concluded that the DHS blade was the superior implant in this study.
With a successful clinical result defined as an excellent or good outcome accompanied by significant pain relief, 73 patients had a successful clinical result.
Recombinant human osteogenic protein-1 (rhOP1 or BMP-7) has now been produced and is commercially available.
We are encouraged by our early experiences with the use of OP1 in numerous anatomical sites and apart from issues of cost would see great potential for further use.
Management of symptomatic residual acetabular dysplasia in adolescence and early adulthood remains a major therapeutic challenge. At our unit the two senior authors review all patients preoperatively and simultaneously perform each procedure. In the four years from 1998 forty-three Bernese osteotomies were performed in 40 patients with residual acetabular dysplasia. The mean average age at surgery was 21 years (range 12 – 43 years) and there were 34 female patients. The indication for surgery was symptomatic hip dysplasia (all idiopathic but for one male with a history of slipped capital femoral epiphysis) presenting with pain and restricted ambulation. 4 patients had previous surgery on the affected hip (2 Salter’s osteotomy, one Shelf procedure and one proximal femoral osteotomy). 27.5% of patients had symptomatic bilateral disease. 42% of patients had Severin class IV or V dysplasia at presentation. 100% of patients had preservation of the hip joint at last follow-up evaluation (mean 2.4 years), with excellent results in 82%, an average post-operative Harris hip score of 96, and an average d’Aubigne hip score of 16.1. The mean post-operative improvements in radiographic measures were as follows: Anterior centre edge angle +19.4°, Lateral centre angle +25.8°, Acetabular Index – 10.7°. Head to Ischial distance – 7.3mm. Surgical operative time decreased from 128 minutes to 43 minutes from the first to the most recent case. Average blood loss has reduced from 1850mls to 420mls over the four years experience. Predonation of 2 units of blood requested from all patients with baseline hemoglobin of >
12g/dl. When combined with intraopera-tive cell salvage the need for transfusion of homologous blood has been eliminated. All complications occurred in the first 9 patients: (one major – iliac vein injury requiring no further treatment; four moderate – lateral cutaneous nerve injuries; four minor – asymptomatic heterotopic ossification). Our experience confirms that the Ganz periacetabular osteotomy is an efficacious procedure for the treatment of the residually dysplastic hip, providing excellent clinical results, where early intervention is the key to improved outcome. It is a technically demanding procedure with a significant early learning curve and we believe that a two
Over the past four decades, internal fixation has continued to gain popularity as a method for treating fractures because of significant improvements in both implant design and materials. This biomechanical study compares the compressive forces generated by a conventional 4.5 AO/ASIF cortical screw lag screw with a differential pitch cortical compression screw in a simulated fracture model using whole bone composite femur. The differential pitch screw investigated in this study generates 82% of the compression generated by a conventional 4.5mm AO/ASIF cortical screw. Proving compression in diaphyseal fractures is achievable using a differential pitch screw. Sufficient compression is generated to allow osteosynthesis using a plate to be preformed independent of the lag screw positioning. It is thus advantageous over the traditional compromise that arises when exposure to the fracture site is limited, of either incorporating the lag screw into the plate of choosing a non-optimal plate or screw position. It is proposed as an adjunct to the internal fixation of long bone fractures and not a single fixation device.
Between 1994 and 2002, 42 patients aged over 65 years were admitted to the spinal injuries unit with odontoid fractures. Data was retrospectively collected by analysis of the national spinal unit database, hospital inpatient enquiry (HIPE) system, chart and x-ray review. Mean age of patients was 79 years (66–88). Mean following-up with 4.4 years (1–9 yrs). Male to female ratio was 1:1.2 (M=19, F=23). Among the mechanism of injury, simple fall (low-energy) was the commonest underlying cause in 76% of the odontoid fracture, whereas 23% fractures were sustained as a result of motor vehicle accident. Fractures were classified according to Anderson and D’Alonzo method. There were 29 (69%) type 11 fractures, 13 (30%) were type 111 fractures and there was no type 1 fracture. Anterior and posterior displacements were recorded with almost equal frequency. Seven fractures displaced anteriorly and six fractures posteriorly. Primary union occurred in 59% of fractures. Forty (95.3%) fractures were treated non-operatively. Two fractures were stabilized primarily with C1/C2 posterior interspinous fusion. These fractures were odontoid type 11, anteriorly displaced. Three fractures (7.1%) failed to unite and another three fractures (7.1%) united with prolonged interval (9–11 months). Neurological compromise was mainly related to displacement of the fracture. The overall complication rate was significant (48%) with an associated in-hospital mortality of 11.1%. Loss of reduction, non-union after non operative treatment, pin site problems and complication due to associated injuries accounted primarily for this significant complication rate. Most fractures can be managed in orthosis but unstable fractures require rigid external immobilization or surgical fixation. Outcome was assessed using a cervical spine outcome questionnaire from Johns Hopkins School of Medicine. Questionnaires were sent by post to all patients identified. Non responders were subsequently contacted by phone, if possible, to complete the questionnaire. In the follow-up, additional 6(14.2%) patients were found deceased, 4 patients were unavailable for review and the remaining 69% had significant recovery. Functional outcome scores approached pre-morbid level in all patients. Outcome of these patients are related to increasing age, co-morbidity and the severity of neurological deficit.