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Biomedical subjects

A Alho

Publications and source records attributed to A Alho.

At least 91 records · Page 5Linked to original sources
PubMed1989

Rotational strength of the femoral neck. Computed tomography in cadavers.

The mean bone density of the femur at different levels was determined by means of quantitative computed tomography (QCT) in 50 pairs of normal cadaveric femora and related to the rotational strength of the femoral neck. All the femora fractured vertically and spirally in the neck. The bone-mass-related measures at different levels were calculated from QCT densities and volumes. Cancellous bone was defined with threshold limits ranging from 50-500 Hounsfield units (HU), and attenuation values exceeding 500 HU were assessed as cortical bone. The recorded QCT mass-related measures of cortical and cancellous bone separately and as total bone masses gave significant right/left correlations. Correlations were found between the ultimate torsional strength of the femoral neck and QCT recordings of bone mass at all the femoral levels. The best correlations were demonstrated between the rotational strength of the femoral neck and the total bone-mass-related measures in the femoral shaft and condylar area. Bone mass of the femur measured by computed tomography may become useful as an index of the mechanical strength of the femoral neck.

Aged↗
PubMed1989

Stability of femoral neck osteosynthesis. Comparison of fixation methods in cadavers.

Fixation of vertical femoral neck osteotomies in 50 cadavers was performed with either von Bahr screws or a sliding hip compression screw. One specimen from each pair of femora was used for the osteotomy, the other serving as an intact control. At 0.05 r of torsion the load-deformation test showed that three von Bahr screws provided the strongest fixation, and this was confirmed by the the ultimate torsional moment test. Regardless of positioning, even two von Bahr screws were stronger than the sliding compression screw with or without an additional lag screw. The results indicate that the best torsional stability in femoral neck fractures can be obtained with three 5.5-mm screws.

Bone Plates↗
PubMed1989

Quantification of bone mineral measured by single-energy computed tomography.

Twenty cadaver femoral condyles were examined with single-energy quantitated computed tomography (QCT), and the composition of the bone scanned was analyzed chemically. The calcium concentration correlated well with the QCT density (r = 0.89, P less than 0.001). The highest correlation was recorded between the total calcium content in the scanned slices and the bone mass-related measures recorded by QCT (r = 0.96, P less than 0.001). Single-energy computed tomography thus provides an accurate measure of total bone mineral content.

Aged↗
PubMed1989

Surgical margin in soft tissue sarcoma. The Scandinavian Sarcoma Group experience.

Two-hundred and forty adult patients with a high-grade soft tissue sarcoma were treated surgically in 18 hospitals participating in the Scandinavian Sarcoma Group Protocol I. The patients were randomized to either postoperative doxorubicin or control; patients whose surgical margin was judged marginal also received radiotherapy. The outcome after different surgical margins was analyzed in 185 tumors of Grades III or IV in the extremities. The total cumulative local tumor control was 91 percent (168 of 185) after a median of 47 months. The cumulative local control rates in the surgical groups were: compartmental or wide amputation--37/37 (100 percent), compartmental local excision--23/24 (96 percent), wide local excision--77/84 (92 percent), marginal excision and radiotherapy--19/21 (90 percent), and marginal excision alone (reevaluated margin)--12/19 (63 percent, significantly lower than others). The risk of local recurrence was 13 times higher after marginal than after compartmental surgery (P = 0.02) and 3 times higher if the tumor was larger than 10 cm (P = 0.05). The treatment with doxorubicin did not influence the risk of local recurrence. The survival rates did not differ significantly in the groups.

Combined Modality Therapy↗
PubMed1989

Early loss of fixation of femoral neck fractures. Comparison of three devices in 244 cases.

In successive series of displaced subcapital femoral neck fractures in the elderly, we operated on 75 cases with three Gouffon screws, 94 with three Mecron screws, and 75 with two von Bahr screws. Redisplacement within 3 months occurred in 20 Gouffon cases, 11 Mecron cases, and 12 von Bahr cases. Poor reduction contributed to the failures in all the groups. Although the reduction results in the three groups were similar, the Mecron group had better fixation and better social recovery than the Gouffon group. We concluded that, in addition to good reduction of the fracture, solid screws also contributed to the stability of the bone-implant construct.

Aged↗
PubMed1989

Bone-mass distribution in the femur. A cadaver study on the relations of structure and strength.

We measured the bone density and volume in the femoral head, cervicotrochanteric, midshaft, and condylar regions by quantitative computed tomography of the femora of 26 elderly cadavers. We also measured the shearing force at fracture of the femora in axial bending; 25 fractures occurred vertically in the neck and only one in the shaft. The bone mass-related measurements, calculated as the product of bone density times volume, increased steadily from the femoral neck down to the condyles. The bone densities of males and females did not differ, whereas the bone volumes were higher in males. Several correlations were found between the ultimate shearing force of the cervical trabecular/cortical bone and cortical and cancellous bone densities in different locations of the femur. The ultimate shearing force was correlated with the bone mass in all the locations.

Absorptiometry, Photon↗
PubMed1988

Open tibial fractures treated with Hoffmann external fixation.

Thirty-two open fractures of the tibial shaft were treated with external fixation between 1973 and 1981. Early amputation was necessary in one patient. In the remainder, including 14 with extensive soft-tissue lesions, wound healing was obtained within 18 weeks, and the median time until full weight bearing without pain was 32 weeks (range 8-60 weeks). Two deep infections healed during the observation period. Among 26 patients examined 1-9 years after the injury, the result was excellent in six, good in 11, fair in four, and poor in five patients (including the amputation). One fracture had not united during the observation period. Four poor results were due to the stiffness of the ankle and foot after compartment syndrome. In conclusion, alertness for early fasciotomy is necessary even in severe open tibial fractures. The external fixation should not be continued longer than the soft tissue and bone reconstruction make it necessary.

Adolescent↗
PubMed1988

Piroxicam and naproxen in patients with osteoarthritis of the hip waiting for total hip replacement.

Two-hundred and fifty-two patients waiting for a total hip replacement for degenerative hip disease were randomized to two groups of nonsteroidal anti-inflammatory medication using piroxicam, 20 mg per day, and naproxen, 750 mg per day, after exclusion for severe dyspepsia or peptic ulcer, asthma, idiosyncracy, dissent, age below 50 years, Harris hip score above 50, or significant contralateral disease. A significant improvement in the pain and daily activity parameters was obtained in both groups. The effect was better in the piroxicam group one month after the commencement of the treatment, and equal in the groups later during the observation period of 2-5 months. We conclude that continuous medication is beneficial in patients with severe osteoarthritis scheduled for operation. However, the side effects of the medication have to be carefully considered and followed up.

Activities of Daily Living↗
PubMed1988

Femoral bone density measurements by single energy computed tomography related to hip fractures.

We measured bone density in various parts of the femur by using single energy quantitative computed tomography. In the cadaver studies we found significant correlations between the trabecular and cortical bone density and the structural strength of the femur in bending and rotational loading. This was observed in parts of the femur distant from the fracture site in the femoral neck. Good reproducibility of the density measurements was obtained at the condylar level, a site easily accessible for clinical measurements. In a clinical study, we could record post-traumatic osteoporotic changes at 5% precision level.

Absorptiometry, Photon↗
PubMed1988

Bone mineral content and mechanical strength. An ex vivo study on human femora at autopsy.

Bone mineral content as determined by computed tomography (CT) and mechanical strength on axial loading were compared in 36 cadaveric femur specimens. In axial loading, 34 femora fractured vertically in the neck, one femur fractured subtrochanterically, and one in the shaft. Based on the CT measurements of density and area, the mass of a transverse slice of the femur was estimated. Highly significant correlations were demonstrated between strength and cancellous bone density. Even higher correlations were revealed when the bone masses of the proximal and distal femoral areas were calculated. Based on these findings, an equal distribution of the effective mass of the femur was postulated.

Adult↗
PubMed1988

Interlocking intramedullary nailing in the treatment of tibial fractures. A report of 45 cases.

Forty-five tibial shaft fractures in 43 patients were treated with the Grosse-Kempf interlocking intramedullary nail. The material was highly selected because 49% of the fractures were due to high-energy trauma and 62% were located at the diaphyseal-metaphyseal junctions. The median time to full weight-bearing was 30 days, and 44 fractures healed by bridging callus in a median of 16 weeks. There was one nonunion, one deep, and one superficial infection. The results of the clinical and radiologic evaluations were excellent in 29 fractures, good in 13, fair in two, and poor in one. Interlocking intramedullary nailing proved to be efficient for comminuted, segmental, and unstable tibial fractures, especially in patients with multiple injuries. Compared with conventional intramedullary nailing, the locking procedure increases the stability at the fracture site and extends the indication for nailing to fractures in the proximal and distal diaphyseal-metaphyseal junctions.

Adolescent↗
PubMed1987

Controlled bending instability in the healing of diaphyseal osteotomies in the rat femur.

Ninety-six rats underwent a midshaft transverse osteotomy followed by osteosynthesis with an intramedullary nail, so that the effect of bending instability on time to union and on the mechanical properties of experimental diaphyseal fracture could be evaluated. Rotation was reduced by cementing both nail ends to the bone. Rigid nails made of stainless steel were used on one group and flexible nails made of polyacetal resin were used on another group. Serial radiographs were evaluated at 4-6-week intervals. Twelve animals with either nail type were killed at 4, 8, 16, and 24 weeks. Both femora were mechanically tested and the callus diameters were measured. There was no significant difference in time to union between the two groups. The cross-sectional area of callus was significantly higher at 8 and 16 weeks in femora with flexible nails. The strength, toughness, and resilience of the bone increased in this group until 24 weeks. Between 16 and 24 weeks, these parameters did not improve in femora with rigid nails. Poorer mechanical properties in femora with steel nails are interpreted as an effect of stress protection of the bone. This study, therefore, indicates that flexible nails prevent stress protection effects without delaying union.

Acetals↗
PubMed1987

Hemijoint allografts in the treatment of low grade malignant and aggressive bone tumours about the knee.

Nine consecutive patients undergoing osteoarticular allogenic transplantation for low grade malignant or aggressively benign tumours have been followed up for between 8 to 15 years. Eight patients had functioning knees whilst 1 ended in arthrodesis. Of the functioning knees all had full extension but only 3 could flex more than 90 degrees. Seven patients had returned to work. Radiologically all the knees showed progressive deterioration. In spite of this only three knees were painful with exercise and none at rest. We conclude that hemijoint allografts represent a useful alternative to make good a bony defect after tumour resection about the knee, but that the ultimate result of such a reconstruction depends on survival of the joint surfaces.

Adolescent↗
PubMed1987

Sliding of the compression hip screw in femoral neck fractures.

Backing out of the compression screw in the sliding screw-plate hip osteosynthesis was analyzed in a series of 71 hips with medial femoral neck fractures during an observation period of 12-42 months, with a median of 26 months. In addition to the compression screw device, a parallel cranial lag screw was used. A postoperative primary diastasis in the fracture space of 1-5 mm in 11 cases did not predispose to major sliding of the screws or to healing problems. Thirteen of 27 fractures with late screw telescoping of 4 mm or more showed healing disturbances, 11 late segmental collapses, and 2 nonunions, compared with 7 disturbances, 6 late segmental collapses, and 1 nonunion among 39 cases with screw gliding of 3 mm or less. The difference was significant (p less than 0.05, Mann-Whitney). Five early mechanical failures were excluded from this analysis.

Adolescent↗
PubMed1987

Strength of femoral neck fracture fixation. Comparison of six techniques in cadavers.

A neck osteotomy parallel to the femoral shaft was made on 36 cadaveric femora using the contralateral intact femur as a control. The osteotomies were fixed using a Thornton nail, two von Bahr screws, three Gouffon screws, three Knowles pins, a Haukebø compression screw, or an AO compression screw. The femora were then tested for bending strength using the load ratio test/control at 2- and 5-mm displacement as an expression of the relative strength of the osteosynthesis. There was no difference between the von Bahr, Haukebø, and the AO screws. These implants gave stronger fixation than the Thornton nail, Gouffon screws, and Knowles pins. The Thornton nail was stronger than three Gouffon screws or Knowles pins. The relatively stronger compression hip screws were thus not superior to two optimally placed 5-mm screws.

Aged↗