Sune Larsson

Use of injectable calcium phosphate cement for fracture fixation: a review.

Injectable osteoconductive calcium phosphate cements have been introduced as an adjunct to internal fixation for treating selected fractures. These cements harden without producing much heat, develop compressive strength, and are remodeled slowly in vivo. The main purpose of the cement is to fill voids in metaphyseal bone, thereby reducing the need for bone graft, but cements also may improve the holding strength around metal devices in osteoporotic bone. Several bioactive cements are being developed. One of these cements, Skeletal Repair System, is available in Europe and has been approved by the United States Food and Drug Administration for use in selected distal radius fractures. Cadaveric studies have shown that using Skeletal Repair System cement with conventional metal fixation in certain fractures of the distal radius, tibial plateau, proximal femur, and calcaneus can produce better stability, stiffness, and strength than metal fixation alone. Early clinical results have shown reduced time to full weightbearing when cement has been used for augmentation of tibial plateau and calcaneal fractures, more rapid gain of strength and range of motion when used in distal radius fractures, and improved stability in certain hip fractures. Bioactive cements in general also may prove useful in vertebroplasty.

Epidemiology of scapular fractures Incidence and classification of 338 fractures

We have studied scapular fractures, with special reference to intraarticular glenoid fractures, during a 10-year period in 2 Swedish counties. There were 338 scapular fractures in 322 patients. The annual incidence was 10/10(5) inhabitants, of which 30 percent affected the glenoid cavity. Out of 100 intraarticular glenoid fractures, 55 occurred in men and 45 in women. The mean age of the women at the time of fracture (64 years) was significantly higher than the mean age of men (49 years). The most common intraarticular glenoid fracture type was the anterior chip fragment fracture which, in about two-thirds of the cases, was associated with shoulder dislocation.

Norian Srs Cement Augmentation in Hip Fracture Treatment: Laboratory and Initial Clinical Results

Bone quality, initial fracture displacement, severity of fracture comminution, accuracy of fracture reduction, and the placement of the internal fixation device are important factors that affect fixation stability. New high strength cements that are susceptible to remodeling and replacement for fracture fixation may lead to improved clinical outcome in the treatment of hip fractures. Norian SRS is an injectable, fast setting cement that cures in vivo to form an osteoconductive carbonated apatite of high compressive strength (55 MPa) with chemical and physical characteristics similar to the mineral phase of bone. It can be used as a space filling internal fixation device to facilitate the geometric reconstruction, load transfer, and healing of bone with defects and/or fractures in regions of cancellous bone. Furthermore, this cement can improve the mechanical holding strength of conventional fixation devices. Use of this material potentially could improve fracture stability, retain anatomy during fracture healing and improve hip function, thus achieving better clinical outcomes. In vivo animal studies have shown the materials biocompatibility, and cadaveric studies have shown the biomechanical advantage of its use in hip fractures. Initial clinical experience (in 52 femoral neck fractures and 39 intertrochanteric fractures) showed the potential clinical use of this innovative cement in the treatment of hip fractures.

Sequelae from clavicular fractures are common: A prospective study of 222 patients

Background Nonoperative treatment is preferred for clavicular fractures irrespective of fracture and patient characteristics. However, recent studies indicate that long term results are not as favourable as previously considered. Methods We have identified predictive risk factors associated with demographic and baseline data on clavicular fractures. In particular, the following symptoms were investigated: pain at rest, pain during activity, cosmetic defects, reduction in strength, paresthesia and nonunion until 6 months after injury. We followed 222 patients with a radiographically verified fracture of the clavicle, and who were at least 15 years of age, for 6 months. Results Nonunion occurred in 15 patients (7%). 93 patients (42%) still had sequelae at 6 months. Displacement of more than one bone width was the strongest radiographic risk factor for symptoms and sequelae. Both radiographic projections used in this study (0° and 45° tilted view) provided important information. A comminute fracture and higher age were associated with an increased risk of symptoms remaining at 6 months. Shortening was not predictive of functional outcome; nor was the site of the fracture in the clavicle. Interpretation The risk for persistent symptoms following nonoperative treatment of clavicular fractures was far higher than expected. Based on these findings it seems reasonable to explore the possibly use of alternative treatment options including surgery for certain clavicular fracture types.

The aetiology and epidemiology of clavicular fractures. a prospective study during a two-year period in Uppsala, Sweden

In a prospective study, the age- and gender-specific incidence and features of clavicular fractures were studied during 1989 and 1990. The population at risk consisted of about 200,000 individuals aged 15 or above in the county of Uppsala, Sweden. There were 187 clavicular fractures in 185 patients corresponding to an annual incidence of 50/100,000 (males 71/100,000, women 30/100,000). Males were significantly younger and sustained comminuted fractures more often than women. The fracture incidence decreased with age in both genders, although the reduction was significant only in men. Bicycle accidents most frequently caused clavicular fractures in both genders, whereas sports activities were significantly more common in men. Right and left clavicles were almost as frequently fractured, and a direct fall on the shoulder was the most frequent mechanism of injury for both genders. There was no difference between genders in the anatomical location with about three of four fractures occurring through the middle part and one of four through the acromial part of the clavicle. Ninety-five percent healed uneventfully, while non-union developed in 5% - evenly distributed between the middle part of the clavicle and the acromial part.

C-reactive protein (CRP) levels after elective orthopedic surgery.

The levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were determined by serial measurements after four types of uncomplicated elective orthopedic surgery. The type of operations chosen for this study were total hip arthroplasty (primary, n = 109; and revisions caused by aseptic loosening, n = 9), unicondylar knee arthroplasty (n = 39), and lumbar microdiskectomy (n = 36). In all patients, CRP levels increased after surgery, reaching peak levels on the third day after hip arthroplasties (primary, 116 +/- 43 mg/l; revisions, 136 +/- 58 mg/l) and on the second day after knee arthroplasties (140 +/- 46 mg/l) and lumbar microdiskectomy (48 +/- 27 mg/l). C-reactive protein levels usually dropped to normal (less than 10 mg/l) within 21 days after surgery. No correlations were found between CRP response and the type of anesthesia, amount of bleeding, transfusion, operation time, administered drugs, age, or gender. Erythrocyte sedimentation rate increased to peak levels about five days after surgery, followed by a slow and irregular decrease. Still, 42 days after uncomplicated operations ESR often remained elevated. In conclusion, the level of CRP must be considered a better diagnostic aid for the early detection of postoperative infections than ESR. It can be assumed that the rapid decline in CRP after uncomplicated orthopedic surgery will be interrupted by a second rise or by a persisting elevated level if infectious complications occur.

Biomechanical comparison of five different atlantoaxial posterior fixation techniques.

Study Design. Five different reconstructions of the atlantoaxial complex were biomechanically compared in vitro in a nondestructive test. Objectives. To determine whether non–bone graft–dependent one-point fixation affords stability levels equivalent to three-point reconstructions. Summary of Background Data. Previous investigations have demonstrated that three-point fixation, using bilateral transarticular screws in combination with posterior wiring, provide the most effective resistance to minimize motion around C1–C2. However, placement of transarticular screws is technically demanding. Posterior wiring techniques affording one-point fixation have failure rates of ∼15%, with failure considered to be secondary to structural bone graft failures. One-point, non–bone graft–dependent fixations have not been tested. Methods. Eight human cervical specimens, C0–C3 were loaded nondestructively. Unconstrained three-dimensional segmental motion was measured. The reconstructions tested were two one-point fixations, one two-point fixation, and two three-point fixations. Results. Under axial rotation two and three-point reconstructions provided better stiffness than the one-point reconstructions (P < 0.05). During flexion–extension, higher stiffness levels were observed in one- and three-point fixations when compared with the intact spine (P < 0.05). In lateral bending no significant differences were observed among the six groups, although the trend was that reconstructions including transarticular screws provided greater stability than one-point fixations. Conclusion. The current findings substantiate the use of three-point fixation as the treatment of choice for C1–C2 instability. [l: atlantoaxial fixation, biomechanics, cervical spine, instability, spinal instrumentation, transarticular screws]

Leisure physical activity and the risk of fracture in men

Background Data from previous studies are inconsistent, and it is therefore uncertain whether, to what extent, and at what level leisure physical activity influences the risk of osteoporotic fractures in men. Methods and Findings A cohort of 2,205 men, 49–51 y of age, was enrolled in a longitudinal, population-based study. Leisure physical activity and other lifestyle habits were established at baseline and at ages 60, 70, 77, and 82 y. During 35 y of follow-up, 482 men had at least one fracture. Coxs proportional hazards regression was used to determine hazard ratios (HRs) of fracture associated with time-dependent physical activity habits and covariates. Men with a sedentary lifestyle (HR 2.56, 95% confidence interval 1.55–4.24) or men who walked or bicycled only for pleasure (HR 1.61, 95% confidence interval 1.10–2.36) had an increased adjusted risk of hip fracture compared with men who participated in regular sports activities for at least 3 h/wk. At the end of follow-up, 8.4% of the men with a high physical activity, 13.3% of the men with a medium physical activity, and 20.5% of the men with a low physical activity had suffered a hip fracture. According to the estimation of population-attributable risk, one third of all hip fractures could be prevented by participation in regular sports activities. High activity also conferred a reduced overall fracture risk. Conclusions Our data indicate that regular sports activities can reduce the risk of fractures in older men.

The use of calcium phosphate bone cement in fracture treatment: a meta-analysis of randomized trials

BACKGROUND Available options to fill fracture voids include autogenous bone, allograft bone, and synthetic bone materials. The objective of this meta-analysis was to determine whether the use of calcium phosphate bone cement improves clinical and radiographic outcomes and reduces fracture complications as compared with conventional treatment (with or without autogenous bone graft) for the treatment of fractures of the appendicular skeleton in adult patients. METHODS Multiple databases, online registers of randomized controlled trials, and the proceedings of the meetings of major national orthopaedic associations were searched. Published and unpublished randomized controlled trials were included, and data on methodological quality, population, intervention, and outcomes were abstracted in duplicate. Data were pooled across studies, and relative risks for categorical outcomes and weighted mean differences for continuous outcomes, weighted according to study sample size, were calculated. Heterogeneity across studies was determined, and sensitivity analyses were conducted. RESULTS We identified eleven published and three unpublished randomized controlled trials. Of the fourteen studies, six involved distal radial fractures, two involved femoral neck fractures, two involved intertrochanteric femoral fractures, two involved tibial plateau fractures, one involved calcaneal fractures, and one involved multiple types of metaphyseal fractures. All of the studies evaluated the use of calcium phosphate cement for the treatment of metaphyseal fractures occurring primarily through trabecular, cancellous bone. Autogenous bone graft was used in the control group in three studies, and no graft material was used in the remaining studies. Patients managed with calcium phosphate had a significantly lower prevalence of loss of fracture reduction in comparison with patients managed with autograft (relative risk reduction, 68%; 95% confidence interval, 29% to 86%) and had less pain at the fracture site in comparison with controls managed with no graft (relative risk reduction, 56%; 95% confidence interval, 14% to 77%). We were unable to compare pain at the bone-graft donor site between the studies because of methodological reasons. Three studies independently demonstrated improved functional outcomes when the use of calcium phosphate was compared with the use of no grafting material. CONCLUSIONS The use of calcium phosphate bone cement for the treatment of fractures in adult patients is associated with a lower prevalence of pain at the fracture site in comparison with the rate in controls (patients managed with no graft material). Loss of fracture reduction is also decreased in comparison with that in patients managed with autogenous bone graft.

Bone reservoir: Injectable hyaluronic acid hydrogel for minimal invasive bone augmentation

A strategy has been designed to develop hyaluronic acid (HA) hydrogel for in vivo bone augmentation using minimal invasive technique. A mild synthetic procedure was developed to prepare aldehyde modified HA by incorporating an amino-glycerol side chain via amidation reaction and selective oxidation of the pendent group. This modification, upon mixing with hydrazide modified HA formed hydrazone-crosslinked hydrogel within 30s that was stable at physiological pH. In vitro experiments showed no cytotoxicity of hydrogel with the controlled release of active bone morphogenic protein-2 (BMP-2). In vivo evaluation of this gel as a BMP-2 carrier was performed by injecting gels over the rat calvarium and showed bone formation in 8 weeks in correlation with the amount of BMP-2 loaded (0, 1 and 30μg) within the gel. Furthermore, hydrogels with 30μg of BMP-2 induced less bone formation upon subcutaneous injection in comparison with subperiosteal implantation. Histological examination showed newly formed bone with a high expression of osteocalcin, osteopontin and with angiogenic bone marrow when higher BMP-2 concentration was employed. Our result suggests that novel HA hydrogels could be used as a BMP-2 carrier and can promote bone augmentation for potential orthopedic applications.