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. General ultrasound screening led to early splinting of 3.4% of the newborns compared with 2.0% for the selectively screened group and 1.8% for the group not receiving ultrasound screening. Using these data, we decided on sequences and intervals of diagnostic and therapeutic actions considered to be sufficient for each regimen. We applied estimates of the costs of screening, treatment of DDH discovered early and late, and follow-up examinations to arrive at total program costs for each strategy. RESULTS: Total program costs were similar for each of the three screening strategies (costs varied by < 5%). However, treatment of late cases accounted for only 22% of total costs in the group undergoing general screening vs 65% in the two latter groups. The cost estimates were sensitive to several variables. Application of the data to a hypothetical ultrasound program in which all girls and only boys at increased risk for DDH underwent an ultrasound examination showed substantially reduced total program costs. CONCLUSIONS: Application of costs from other centers to our data regarding frequency of clinical outcomes may yield different comparative program costs. If the findings of our clinical study can be generalized to other centers, a strategy of screening all girls and boys with risk factors for DDH may be the most cost-effective approach.

Regeneration of calvarial defects by a composite of bioerodible polyorthoester and demineralized bone in rats.

A study was performed to evaluate regeneration of defects in rat calvaria either unfilled or filled with a bioerodible polyorthoester only, demineralized bone only, or a composite of both. At 4 weeks, histological and radiographic studies showed that defects filled with a composite of bioerodible polyorthoester and demineralized bone or demineralized bone alone were bridged by bone. Unfilled defects or defects filled with polyorthoester only did not heal. The polyorthoester caused slight inflammation that subsided by 3 weeks, and only traces of the filler could be detected at 4 weeks. The polyorthoester provided local hemostasis when used either alone or in composites with demineralized bone. The composite implant was moldable, easily contoured, and technically easier to use than demineralized bone alone.

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. No material was implanted in the defects in the Group-D rats. The rats were killed fifty days postoperatively. The formation of bone in the defects was quantified with computer-assisted measurements of the area on radiographs. The host-tissue response was evaluated with light microscopy. Defects that had been filled with the composite of polyorthoester and demineralized bone or with demineralized bone alone showed regeneration of bone corresponding to 93.6 and 77.6 per cent of the area of the defect, respectively. Defects that had no implant or that had been filled with polyorthoester alone showed significantly less formation of bone. No inflammation was seen with light microscopy, and only traces of the polyorthoester could be detected in the defects that had been filled with the composite or with polyorthoester alone.

Inhibition of heterotopic osteogenesis in rats by a new bioerodible system for local delivery of indomethacin.

A study was done to evaluate the effect of a system for the local delivery of indomethacin on demineralized bone-induced formation of heterotopic bone in the abdominal muscles of rats. Two separate investigations were conducted on a total of forty-eight Wistar rats. In both series, two types of implants were used: polyorthoester and demineralized bone (Group A, the control group) and polyorthoester with 5 per cent indomethacin and demineralized bone (Group B, the experimental group). In the first series, host-tissue responses and osteoinduction were evaluated histologically at two, three, and four weeks after the implantation. In the second series, the formation of bone was quantified on the basis of uptake of 85Sr at four weeks after the implantation. The polyorthoester system for the local delivery of indomethacin significantly inhibited demineralized bone-induced heterotopic formation of bone, as demonstrated by light microscopy and by uptake of 85Sr. The polyorthoester, with or without the drug, caused little tissue reaction and was resorbed almost completely at four weeks.

Mixed-image planimetry. Assessment of a new method for stereometric analysis in microscopy.

A new method for stereometric measurement of surface area in microscopy is described, based on the mixed-image principle. The measurement was accomplished by observing the area on which was superimposed the image of a miniature electric lamp attached to an ordinary planimeter. Mixed-image planimetric measurements were more easily made and required much less time than area calculation by an integrating eyepiece, by weight or by ordinary planimetric measurements of photomicrographs or tracings of the area. Mixed-image planimetric measurements of a finite area varied less than 1 per cent. Such precision was not obtained with the other methods. The new method was devised in vivo stereometric measurements of bone tissue remodelling in rabbit ear chambers, but should find a much wider application in quantitative microscopy of both finite and extensive objects.

A novel titanium rabbit ear chamber for vital microscopy of bone tissue.

Seventy-eight small titanium-glass culture chambers of own design for vital microscopy of bone tissue were inserted in the ears in 41 rabbits. After insertion without removing the cartilage on the inner side of ears not previously operated upon, 44 out of 56 chambers (79 per cent) became vascularized. It proved satisfactory for bright field, fluorescence and polarized light microscopical observations of living bone tissue for half a year or longer.

Osteogenesis in rabbit ear chambers.

Heterotopic osteogenesis was studied in vivo by grafting 246 bone tissue grafts onto 39 cultures chambers inserted in the ears of 27 rabbits. Bone formation was obtained from 23 out of 24 autografts placed inside the optical part (greater than 0.1 mm deep) of 8 ear chambers. No bone tissue formation was observed in the optical part (less than 0.1 mm deep) of 23 chambers in which a total of 129 autografts had been placed in a communicating deeper non-optical part. Bone formation was always obtained after autografting bone tissue to the non-optical part of a titanium-glass ear chamber of own design, and bone tissue entered the optical part of these chambers when this was deeper than 0.1 mm. The possible source of bone formation in rabbit ear chambers is mentioned. Resorption of bone tissue autografts was regularly obtained.

Effect of indomethacin on bone remodelling in rabbit ear chambers.

The effect of indomethacin medication on bone tissue resorption and formation was assessed by qualitative and quantitative microscopy in vivo in 18 rabbit ear chambers in 12 rabbits. Five bone tissue experiments were carried out during half a year using the rabbits as their own controls. One daily oral indomethacin dosage of 10 mg/kg body weight given for 3 weeks inhibited resorption of bone autografts in this type of vital chamber and thus inhibited disordered osteoclastic activity. The effect of indomethacin on ordered osteoclastic activity was not quantitated, nor was its effect on parallel-fibred bone tissue formation assessed. The same dosage of indomethacin clearly retarded woven-fibred bone tissue formation (by 1 week) as compared to control experiments, in which the chambers were used as their own controls. It is concluded that indomethacin treatment of patients liable to develop para-articular ossifications therefore seems rational. Indomethacin and drug-induced arthropathy of the hip-joint is discussed in relation to the presented results. A final appraisal of the role of indomethacin in this complex process must await additional material.

Bone remodelling in rabbit ear chambers. A vital microscopical and histological study.

Heterotopic autologous bone tissue was studied by vital microscopy in rabbit ear chambers and correlated with the findings from histological sections prepared from the same tissue. The in vivo morphology and remodelling of different bone types were thereby characterized. Autografts were resorbed in a disordered fashion by osteoclasts and woven-fibred bone tissue formed on such grafts. Later parallel-fibred bone, bounded by a seam of osteoid tissue, formed on this scaffold. Bone flakes growing underneath the cover glass were remodelled into shallow hemi-ossicles containing fat marrow, which were always oriented towards the cover glass. Following en bloc removal of the central part of the bone culture, woven-fibred bone rapidly formed within the new connective tissue, filling in the empty space. Such bone was remodelled into cancellous bone containing fat marrow. A balance between resorption and formation was regularly established in the chambers. The bone cultures were thus useful for vital microscopical studies for half a year or longer. In the present study bone remodelling in rabbit ear chambers closely resembled that of orthotopics bone. Ear chamber bone cultures are therefore a versatile in vivo biological model for dynamic bone tissue studies at both tissue and cellular levels.

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. METHODS: The development of the uncemented femoral stem was part of an innovation process to fulfill the combined requirements. The stem was designed with two longitudinal semicircular grooves to accommodate a drill bit to unanchor the stem. These grooves were interconnected by canals, each 1 mm in diameter. The surface was partly coated with hydroxyapatite (HA). The stems were inserted in the left hip of 35 goats. Perioperatively, the grooves were filled with autologous bone grafts, and standard cemented canine acetabular component and head were used. The pull-out force was measured six months postoperatively. Following randomization, 11 animals had the grooves of the stem drilled to remove anchoring tissue. Twelve animals were left undrilled (controls). RESULTS: There was a significant difference in mean pull-out force between the group that had been drilled (1526 N) compared with the controls (2033 N, p = 0.028). Most of the HA had been resorbed. CLINICAL SIGNIFICANCE: The stems had a high retention force. The procedure for un-anchoring by drilling significantly reduced the pull-out force.

Treatment of chronic osteomyelitis by free grafts of cancellous autologous bone tissue. A preliminary report.

Chronic osteomyelitis was treated by free grafts of autologous bone tissue in 13 consecutive patients aged 18 to 81 to years. In all patients the osteomyelitis was located in the leg, and Staphylococcus aureus was the causative organism. Seven had an infected non-union. The duration of the osteomyelitis varied from less than 1 year to 75 years. Surgical debridement and grafting of cancellous and cortical cancellous bone were performed at the one operation. The osteomyelitis healed after a single operation in all patients but one, who needed three operations before the infection was eradicated. In one patient a second bone grafting operation was necessary before weight-bearing could be allowed. Although the number of patients is small, the results agree well with larger series published recently. Grafting of autologous bone tissue seems to be a very valuable method of treatment for chronic osteomyelitis.

Mixed-image longitudimetry: a new method of length measurement in microscopy.

A simple and inexpensive instrument called a longitudimeter for measuring distances in microscopy was constructed from a precision map-measuring device and an electric lamp positioned eccentrically on a stand. A precision better than 1% was readily obtained in measurements of the perimeters of trabecular surfaces in cancellous bone. Mixed-image longitudimetry was devised for length measurements in cancellous bone, but the method seems suitable for a wider application in quantitative microscopy.

The painful chronic anterior lower leg syndrome. A prospective clinical and experimental study.

A presumed painful chronic anterior lower leg syndrome was diagnosed in 51 patients (73 legs), 30 women and 21 men, aged 11 to 70 years, over a 2-year period. The duration of the syndrome varied from 1 month to 10 years. The patients' main complaint was pain when walking located in the medial ventral muscle compartment of the lower leg. In addition 10 of the patients (15 legs) had leg pain at rest as well and 12 (15 legs) had paresis of the extensor muscles. Thirty-four paired intracompartmental pressure recordings with the wick technique in 6 patients suggest that the more severe the syndrome the lower the pressure in the tibialis anterior muscle. Blind diathermic fasciotomy in 25 patients (36 legs) with a typical history relieved the pain and paresis completely or partly in 33 (92 per cent) out of 36 legs. No postoperative complications worth mentioning were observed. It is concluded that: 1) a chronic painful anterior lower leg syndrome should be suspected in patients with pain on walking and at rest located in the ventral part of the lower leg; 2) intracompartmental pressure measurements seem to be of little preoperative diagnostic value in non-selected patients; 3) blind diathermic fasciotomy of the anterior, medial compartment of the lower leg, including the extensor retinaculum, gives relief from pain and paresis in most patients with a typical history.

[Congenital short Achilles tendon. A survey of habitual toe-walking in children]. / Medfødt kort akillessene. Utredning av habituell tågang hos barn.

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. The disease may be inherited. The diagnosis should be made by an orthopaedist, and the treatment is either conservative with aggressive physical therapy, or surgery. The prognosis is good after early diagnosis and special treatment. A review of the literature, with emphasis on diagnosis and treatment, is presented, together with a brief review of five patients operated by the authors.

Indomethacin-induced delayed fracture healing.

A patient with an ankle joint fracture-dislocation was preoperatively treated with indomethacin. As in previous animal experiments, indomethacin was found to have an inhibitory effect on bone formation. It is suggested that indomethacin should be used with caution if periosteal fracture healing is anticipated.

Indomethacin-induced inhibition of haversian remodelling in rabbits.

The effect of indomethacin on haversian remodelling in the radius was studied in 16 rabbits. An osteotomy and a saw-cut almost through the bone were made in the middle and distal parts of the right radius, respectively. In order to obtain biological osteosynthesis in the osteotomy and the saw-cut the rabbits were not treated in any way during the following 3 weeks. They were then given either indomethacin or placebo suspensions per os, 10 mg/kg/day for 2 weeks, followed by 5 mg/kg/day for 4 weeks. The extent of haversian remodelling was estimated by calcein and oxytetracycline fluorochrome labels given at the start of the indomethacin treatment and 3 weeks later, respectively. After 2 weeks of indomethacin treatment (10 mg/kg/day) the indomethacin plasma levels were about 0.18 microgram/ml 24 hours after the last dose. Indomethacin treatment significantly (2P less than 0.019) inhibited haversian remodelling as estimated by fluorochrome labelling.

Anterior displacement of the tibial tuberosity in the treatment of chondromalacia patellae.

Anterior displacement of the tibial tuberosity combined with shaving of the diseased cartilage was used as treatment for chondromalacia patellae in 32 knees in 28 consecutive patients and in one patient with chondromalacia femoris. The patients were aged 17 to 57 years. One patient had earlier sustained a serious injury to the ligaments of the knee, resulting in instability. All patients except one were unfit for work before the operation. Postoperative extra-articular wound infection was noted in two knees and venous thrombosis occurred in three legs. The postoperative observation period varied from 8 months to 2 years and 10 months. In one knee the anterior displacement of the tibial tuberosity was not maintained. In lateral radiographs the anterior displacement of the tibial tuberosity in the other knees varied from 10 to 23 mm. The relief from pain obtained by the operative treatment was estimated as good in all knees except three, which were unchanged. All patients became fit for work and/or sport.

[Rationalization of the recording of case histories using a modular system]. / Rasjonalisering av epikriseskriving med moduloppbygde epikriser.

Delay often occurs in preparing the case history and treatment summary for transmission to the general practitioner. At the Hagavik Orthopaedic Hospital this delay is reduced to about five days by preparing the summary on a modular system consisting of four modules; the biographical data of the patient, admission and discharge dates and the treatment classified, an abstract of the patient's hospital record and discharge notes. Since 1986 the two first modules have been prepared by computer, which has reduced secretarial work by about one week per 1,000 summaries.

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. In ten patients skin sensation was reduced and three had a limp. All patients were treated with tenotomy. At follow-up after an average of 8 (1-16) years, eight patients had pain relief. Two-thirds of the patients evaluated their clinical state as being better.