Can bone apposition predict the retention force of a femoral stem? An experimental weight-bearing hip-implant model in goats.

Background: The increasing incidence of prosthesis revision surgery in the Western world has led to an increased focus on the capacity for stem removal. We previously reported on a femoral stem implanted in goats with an approximate 15% reduction in retention force by drilling longitudinally orientated grooves on the side of the stem. In this current study, we aimed to histologically evaluate the bony apposition towards this stem and correlate this apposition with the pullout force.

Assessment of retention force and bone apposition in two differently coated femoral stems after 6 months of loading in a goat model.

Background: Since the introduction of uncemented hip implants, there has been a search for the best surface coating to enhance bone apposition in order to improve retention. The surface coating of the different stems varies between products. The aim was to assess the retention force and bone adaption in two differently coated stems in a weight-bearing goat model.

Christiansen's artificial hip joints--what went wrong?

Modern arthroplasty is undoubtedly the greatest contribution that orthopaedic surgery has ever made to medical science. The honour for the good results achieved with total hip replacement surgery goes chiefly to the Briton John Charnley (1911-1982). However, the Norwegian Tor Aas Christiansen (1917-1981) has also earned a place in this history.

Pelvic joint fusions in patients with chronic pelvic girdle pain: a 23-year follow-up.

Purpose: Fusion of the sacroiliac joints (SIJ) has been a treatment option for patients with severe pelvic girdle pain (PGP). The primary aims were to evaluate the long-term outcomes in patients who underwent SIJ fusion and to compare 1-year outcomes with long-term outcomes. The secondary aim was to compare patients who underwent SIJ fusion with a comparable group who did not.

Development of a femoral stem providing strong anchorage and facilitated removal. An experimental study in goats.

Objective: Prosthetic elements must be securely anchored to bone. Should revision surgery be necessary, preservation of bone stock is crucial. The goal of this study was to develop and assess a femoral stem combining secure anchorage and facilitated removal in a goat model.

Histologically verified bone wax (beeswax) granuloma after median sternotomy in 17 of 18 autopsy cases.

Aim: To evaluate the sternum from ordinary or forensic autopsy cases with a midline sternal cutaneous scar macro- and microscopically and using computed tomography (CT) to detect if the haemostatic bone sealant bone wax (beeswax) had been applied after median sternotomy and if the bone wax had elicited inflammation.

Methods: During a 3-year period, the sterna of 18 consecutive cadavers (15 ordinary autopsies, 3 forensic) who prior to death had undergone surgery with median sternotomy were examined macro- and microscopically and with CT. In addition, one virgin sternum was smeared with bone wax at the upper half after bench sternotomy, sutured and examined with CT.

Piriformis muscle syndrome in 19 patients treated by tenotomy--a 1- to 16-year follow-up study.

We treated 19 patients with piriformis muscle syndrome. All patients complained of pain in the buttocks and the posterior thigh. Clinically the buttock was tender and passive stretching increased the pain.

Biocompatibility and effect on osteogenesis of poly(ortho ester) compared to poly(DL-lactic acid).

Implantation of demineralized bone induces new bone formation by the action of contained growth factors, of which bone morphogenetic proteins are of prime importance. A biodegradable polymer may be used as a carrier for demineralized bone particles or recombinant bone growth factors to prevent displacement of the implant, preserve its volume and shape, and assure sustained release of the incorporated active components. A polymer for this use should be biocompatible and completely absorbed without interfering with the osteogenesis.

[Lumbar intervertebral disk prolapse in adolescents].

We investigated the incidence, history, clinical findings and results of treatment of lumbar intervertebral disc herniation in adolescents. During the period January 1992 to medio March 1995 we operated on 20 adolescents aged 15 to 19 years (3.4% of all cases of lumbar disc herniation).

Cost-effectiveness of ultrasonographic screening for congenital hip dysplasia in new-borns.

Objective: Screening for congenital dysplasia of the hips (CDH) of new-borns, mostly by Ortolani's of Barlow's tests, is widely performed, but nevertheless dysplasias are still discovered late. Ultrasonographic screening has been reported to reduce the number of these cases. The present investigation is intended to evaluate the cost-effectiveness of such as screening programme.

Local delivery of indomethacin by a polyorthoester inhibits reossification of experimental bone defects.

Inhibition of orthotopic reossification after surgical removal of bone is sometimes indicated and may be accomplished by implantation of interpositional materials or by systemic administration of indomethacin. However, implantation of nonresorbable foreign material may induce a chronic inflammation and predispose to infections; and systemic administration of indomethacin may induce systemic adverse effects. We studied the effect of local delivery of indomethacin by a bioerodible polyorthoester on the reossification of segmental defects of the radius in rats.

Cost-effectiveness of alternative screening strategies for developmental dysplasia of the hip.

Objective: To compare the cost-effectiveness of adding either a general or a selective ultrasound screening program to the routine clinical examination for developmental dysplasia of the hip (DDH) with use of the data from a large, randomized study of 11,925 newborns.

Methods: Our previous study comparing the clinical outcomes of three strategies for screening infants for DDH suggested (but results were not statistically significant) that general ultrasound screening resulted in fewer children requiring hospitalization and surgery for DDH than did a strategy based on ultrasound screening of the 11.8% of infants considered to be at increased risk of DDH or one with no ultrasound screening.

Ethylene oxide gas sterilization does not reduce the osteoinductive potential of demineralized bone in rats.

It has been shown that different sterilization procedures of demineralized bone may influence its osteoinductive properties. The aim of this study was to evaluate the effect of ethylene oxide sterilization for 1, 3, and 6 hours on the osteoinductive potential of allogeneic demineralized bone implanted heterotopically in rats. Sixty male Wistar rats were randomly assigned to one of four groups, A through D, and four demineralized bone chips (2.

Systemic and local silver accumulation after total hip replacement using silver-impregnated bone cement.

In a patient, at revisional Christiansen total hip arthroplasty, silver-impregnated bone cement was used as prophylaxis against deep infection. Five years later the patient developed serious neurological deficits, and the prosthesis was loose. The loose Christiansen prosthesis and the silver-impregnated bone cement were removed and a Charnley prosthesis inserted.

Complications secondary to the use of standard bone wax in seven patients.

Ordinary bone wax, manufactured from beeswax, was used to stop bleeding from cancellous bone in elective surgery among seven women. Five of them had a resection of a calcaneal exostosis and bursa at the insertion of the calcaneous tendon, one underwent a resection of a medial exostosis of the first metatarsal head, and one had an acromial resection. Postoperatively, all patients had disabling local pain and tenderness.

Assessment in rats of a new bioerodible bone-wax-like polymer.

Holes drilled in rats' skull, iliac crest, and tibia were filled with beeswax or with a new, wax-like, bioerodible polyorthoester (Alzamer). Empty drill-holes served as controls. In addition, beeswax and polyorthoester were deposited between the left and the right oblique abdominal muscles, respectively.

The effect of a composite of polyorthoester and demineralized bone on the healing of large segmental defects of the radius in rats.

The effect of a composite of demineralized bone mixed with polyorthoester on the healing of large segmental defects in the rat radius was studied. Sixty male Wistar rats were divided into four groups, A through D, and an osteoperiosteal diaphyseal defect of 50 per cent of the length of the bone was made in the right radius of each rat. In Group A, the defect was filled with polyorthoester and demineralized bone; in Group B, demineralized bone; and in Group C, polyorthoester.

Bone induction by composites of bioresorbable carriers and demineralized bone in rats: a comparative study of fibrin-collagen paste, fibrin sealant, and polyorthoester with gentamicin.

Host tissue response and heterotopic osteoinduction by composites of demineralized bone matrix and three different substances used as bioresorbable carriers implanted in the abdominal muscles were evaluated by strontium 85 uptake and histology 4 weeks postoperatively in 60 male Wistar rats. Both fibrin-collagen paste and fibrin sealant inhibited bone induction and produced a chronic inflammation; part of the fibrin-collagen paste was still present at 4 weeks. Polyorthoester with gentamicin was almost completely absorbed, induced minimal tissue reaction, and did not inhibit osteoinduction.

[Congenital short Achilles tendon. A survey of habitual toe-walking in children].

Congenital short tendo calcaneus is seen in children as partial or complete walking on the toes, and may represent a major disturbance for normal motor development and coordination. This clinical finding may indicate a more serious, underlying disease (cerebral paresis, childhood psychosis or a neuromuscular disorder). If the patient, apart from walking on the toes exhibits normal clinical findings, the diagnosis of congenital short tendo calcaneus may be justified.

Comparison of histomorphometry and 85Sr uptake in induced heterotopic bone in rats.

Heterotopic bone formation in the abdominal muscle of 45 male 8-week-old Wistar rats induced by implantation of 5, 10, or 15 mg demineralized bone (DBM) powder was evaluated at 4 weeks by 85Sr uptake of the implants and area histomorphometry of the induced bone. Two indices of 85Sr uptake were calculated: the osteogenic index [(counts/min/mg implant)/(counts/min/mg os ilium)] and an index that we have called the osteoquantum index in which the weight of the implant is disregarded [(counts/min implant)/(counts/min/mg os ilium)]. The osteoquantum index showed a linear relationship to the area of the induced bone with a correlation coefficient (r) of 0.

Fracture healing in rats inhibited by locally administered indomethacin.

We studied the inhibitory effect of indomethacin on fracture healing in 135 young, male rats after oral administration compared with local application into the fracture. A closed mid-diaphyseal fracture of the left femur was performed in all the rats. The fractures were not immobilized.