Jan Erik Madsen

Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal femoral fractures: a comparative study with the Gamma nail and compression hip screw.

OBJECTIVE To compare the results after operative treatment of unstable per- and subtrochanteric fractures with the Gamma nail, compression hip screw (CHS), or dynamic hip screw with a laterally mounted trochanteric stabilizing plate (DHS/TSP). DESIGN Prospective. PATIENTS One hundred seventy patients with unstable trochanteric femoral fractures surviving six months after operation. Eighty-five patients were randomized to treatment with the Gamma nail (n = 50, Gamma group) or the compression hip screw (n = 35, CHS group) and compared with a consecutive series of eighty-five patients operated with the dynamic hip screw with a laterally mounted trochanteric stabilizing plate (DHS/TSP group) MAIN OUTCOME MEASUREMENTS Radiographs were analyzed for fracture classification, evaluation of fracture reduction, implant positioning, later fracture dislocation, and other complications. Pre- and postoperative functional status of the patients were recorded, with a minimum of six months follow-up. RESULTS Eighteen percent of the patients in the Gamma group, 34 percent in the CHS group, and 9 percent in the DHS/TSP group suffered significant secondary fracture dislocation during the six months follow-up, leading to a varus malunion, lag screw cutout, or excessive lag screw sliding with medialization of the distal fracture fragment. Two patients (4.0 percent) in the Gamma group suffered an implant-related femoral fracture below the nail, and one had a deep infection. The reoperation rates were 8.0 percent in the Gamma group, 2.9 percent in the CHS group, and 5.9 percent in the DHS/TSP group. All but one fracture in the Gamma and CHS groups and two fractures in the DHS/TSP group healed within six months. Approximately three-fourths of the patients had returned to their preoperative walking ability after six months, with a trend toward better functional outcome in the DHS/TSP group. Use of a TSP reduced the secondary lag screw sliding as compared with the conventional CHS, without affecting fracture healing. CONCLUSION The TSP may be an aid in the treatment of these difficult fractures because the problem with femoral shaft fractures using the Gamma nail is avoided and the medialization of the distal fracture fragment frequently associated with the CHS is prevented.

Hemiarthroplasty or internal fixation for intracapsular displaced femoral neck fractures: randomised controlled trial

Objective To compare the functional results after displaced fractures of the femoral neck treated with internal fixation or hemiarthroplasty. Design Randomised trial with blinding of assessments of functional results. Setting University hospital. Participants 222 patients; 165 (74%) women, mean age 83 years. Inclusion criteria were age above 60, ability to walk before the fracture, and no major hip pathology, regardless of cognitive function. Interventions Closed reduction and two parallel screws (112 patients) and bipolar cemented hemiarthroplasty (110 patients). Follow-up at 4, 12, and 24 months. Main outcome measures Hip function (Harris hip score), health related quality of life (Eq-5d), activities of daily living (Barthel index). In all cases high scores indicate better function. Results Mean Harris hip score in the hemiarthroplasty group was 8.2 points higher (95% confidence interval 2.8 to 13.5 points, P=0.003) at four months and 6.7 points (1.5 to 11.9 points, P=0.01) higher at 12 months. Mean Eq-5d index score at 24 months was 0.13 higher in the hemiarthroplasty group (0.01 to 0.25, P=0.03). The Eq-5d visual analogue scale was 8.7 points higher in the hemiarthroplasty group after 4 months (1.9 to 15.6, P=0.01). After 12 and 24 months the percentage scoring 95 or 100 on the Barthel index was higher in the hemiarthroplasty group (relative risk 0.67, 0.47 to 0.95, P=0.02. and 0.63, 0.42 to 0.94, P=0.02, respectively). Complications occurred in 56 (50%) patients in the internal fixation group and 16 (15%) in the hemiarthroplasty group (3.44, 2.11 to 5.60, P<0.001). In each group 39 patients (35%) died within 24 months (0.98, 0.69 to 1.40, P=0.92) Conclusions Hemiarthroplasty is associated with better functional outcome than internal fixation in treatment of displaced fractures of the femoral neck in elderly patients. Trial registration NCT00464230.

Should insertion of intramedullary nails for tibial fractures be with or without reaming? A prospective, randomized study with 3.8 years' follow-up.

Objective To determine if any differences exist in healing and complications between reamed and unreamed nailing in patients with tibial shaft fractures. Design Prospective, randomized. Setting Level 1 trauma center. Patients Forty-five patients with displaced closed and open Gustilo type I–IIIA fractures of the central two thirds of the tibia. Intervention Stabilization of tibial fractures either with a slotted, stainless steel reamed nail or a solid, titanium unreamed nail. Main Outcome Measurements Nonunions, time to fracture healing, and rate of malunions. Results The average time to fracture healing was 16.7 weeks in the reamed group and 25.7 weeks in the unreamed group. The difference was statistically significant (P = 0.004). There were three nonunions, all in the unreamed nail group. Two of these fractures healed after dynamization by removing static interlocking screws. The third nonunion did not heal despite exchange reamed nailing 2 years after the primary surgery and dynamization with a fibular osteotomy after an additional 1 year. There were two malunions in the reamed group and four malunions in the unreamed group. There were no differences for all other outcome measurements. Conclusion Unreamed nailing in patients with tibial shaft fractures may be associated with higher rates of secondary operations and malunions compared with reamed nailing. The time to fracture healing was significantly longer with unreamed nails.

No difference in functional and radiographic results 8.4 years after quadricortical compared with tricortical syndesmosis fixation in ankle fractures

Objective: To assess long-term functional and radiologic results after two types of syndesmosis fixation, comparing one quadricortical syndesmotic screw fixation with two tricortical screw fixation in ankle fractures. Design: Follow up of a previously conducted prospective, randomized clinical study. Setting: University clinic, Level I trauma center. Patients: Forty-eight patients with closed ankle fractures and concomitant syndesmotic rupture were operated on with quadricortical (n = 23) or tricortical (n = 25) syndesmotic fixation. Results: Follow-up time was 8.4 years (range, 7.7-8.9 years). There were no statistical differences in the two groups regarding Olerud-Molander Ankle score, Orthopaedic Trauma Association score, or degree of osteoarthritis. Patients with a difference in the syndesmotic width between the operated and the nonoperated ankle of 1.5 mm or more showed a tendency toward poorer functional results (P = 0.056). Twenty-one patients showed synostosis on plain radiographs. Of these, only seven patients had synostosis verified on computed tomography, all of whom had significantly worse function. Patients with a posterior fracture fragment at time of operation had poorer Olerud-Molander Ankle score (73.1 versus 85, P = 0.05) and all had osteoarthritis as compared with 55% of those without a posterior fragment. Obese patients (body mass index greater than 30 kg/m2) also had poorer Orthopaedic Trauma Association score, but neither obesity nor being overweight predicted late arthritis. Conclusions: Follow up 8.4 years after surgery of ankle fractures with syndesmotic injury showed satisfactory functional results with only minor differences between the two groups of syndesmotic fixation. Obese patients had significantly poorer functional results. The presence of a posterior fracture fragment was an important negative prognostic factor regarding functional results. Plain radiographs overestimated tibiofibular synostosis. Synostosis on computed tomography, however, predicted impaired ankle function. A difference in syndesmotic width 1.5 mm or greater between the two ankles seemed to be associated with an inferior clinical result.

Bone mineral density and bone structure parameters as predictors of bone strength: an analysis using computerized microtomography and gastrectomy-induced osteopenia in the rat.

In this study the relationships of bone mineral density (BMD) and bone structure parameters calculated from 2D microtomography images to bone strength were investigated. Femurs from 21 male Sprague Dawley rats were subjected to dual-energy X-ray absorptiometry, computerized microtomography (CmicroT) and either three-point cantilever bending (femoral shaft) or two-point bending compression (femoral neck). Gastrectomy was performed on 12 animals and 9 were sham operated. From the tomograms bone structure analysis was performed using a software routine based on grey level run-length method. Correlations of BMD and bone structure parameters to mechanical parameters were investigated as were differences between the gastrectomized and the control samples. The reductions of BMD between the groups were 21 and 27% in the femoral neck and shaft, respectively. For the shaft, the correlations of BMD to all mechanical parameters were significant and BMD was a consistent predictor of bone strength for cortical bone. However, in the femoral neck where cancellous bone predominates, BMD was weakly correlated only to deflection. A significant correlation between trabecular thickness and neck bone strength was found. Hence, compared to trabecular thickness, BMD was of limited value in predicting bone strength in the femoral neck.

Fracture healing and callus innervation after peripheral nerve resection in rats.

The effects of femoral and sciatic nerve resection on fracture healing and innervation of the fracture callus were studied using a stable fracture model. In 34 rats the right tibia was subjected to a standardized closed fracture and stabilized with a modular intramedullary nail. In half of the animals, resection of 1 cm of the femoral and sciatic nerves was performed (nerve resection group), whereas the other animals had sham operations (sham group). To avoid unequal loadbearing between the two groups, all fractured hindlimbs were immobilized in a plaster of Paris cast. The trial was terminated after 5 weeks of fracture healing. Callus size was scored radiographically, and bone mineralization was measured by 85Strontium incorporation. Seven rats from each group had immunohistochemical examination for neural regeneration and ingrowth. Antisera for protein gene product 9.5, necurofilaments, neural growth associated protein 43/B-50, calcitonin gene related peptide, and substance P were used. The mechanical properties of the healing fractures were recorded in a three-point cantilever bending test After 5 weeks, the normally innervated, fractured tibias had regained approximately 50% strength compared with the unfractured side, in comparison with only 20% in the animals that had nerve resection. Although the fracture calluses were mechanically weaker, they were significantly larger in the nerve resection group, indicating defects in tissue composition or organization rendered by the nerve injury. The mineralization rate, as measured by 85Strontium incorporation, was the same in the two groups. However, the nerve resection did not provide complete denervation but changed the innervation pattern of the healing fracture, as the density of sensory nerve fibers immunostainlng for substance P and neu-rofilaments was less in the group with femoral and sciatic nerve resection. The results suggest that intact innervation is essential for normal fracture healing because nerve injury induced a large, but mechanically insufficient, fracture callus.

No adverse effects of clodronate on fracture healing in rats

Clodronate was administered daily 28 days before and after an experimental tibial fracture in 35 male rats, and the effect on fracture healing and posttraumatic bone loss was studied. 5 groups were tested. The clodronate/clodronate group received clodronate in daily doses of 10 mg/kg body weight for 28 days before being subjected to a standardized fracture of the right tibia, and during the fracture healing period of 28 days. The clodronate/saline group received clodronate before fracture and saline during the healing period. The saline/clodronate group received saline before and clodronate after fracture. The saline/saline group received saline only, while the control group served as unfractured, untreated controls. After 28 days of fracture healing, the tibias were evaluated with dual energy x-ray absorptiometry, and tested mechanically in a 3-point ventral bending test. Bone mineral content and bone mineral density were approximately 30% higher in the groups receiving clodronate during the experiment, compared to the untreated groups. The weight and cross-sectional area of the fracture callus were equal in all groups. Whether clodronate was administered before the fracture, after the fracture or both, did not affect the bone mineral. Ultimate bending moment, energy absorption, stiffness and deflection were not significantly different between the groups. Our findings suggest that clodronate increases bone mineral both when given before and after a tibial shaft fracture, without affecting fracture healing at 28 days.

MRI diagnosis of occult hip fractures.

Background Most fractures of the proximal femur are easily diagnosed by conventional radiography. When the images are judged to be negative or equivocal and a clinical suspicion of fracture persists, another approach is to use magnetic resonance imaging (MRI) to help reach a diagnosis. Methods In a prospective study running from November 1998 to December 2001, we registered all patients being examined by MRI who had had a negative or equivocal radiograph and where there was continued clinical suspicion of hip fracture. Results 100 consecutive patients (67 women) were included, with an average age of 80 (37–100) years. The MRI examinations corresponded to 4% of the 2,350 patients admitted with hip trauma during the study period. 46 patients had a femoral neck or intertrochanteric fracture on MRI. 27 patients had other fractures. 18 had other findings on MRI, and 10 were interpreted as being negative, although one of these was a false negative. In a separate interobserver analysis, two experienced radiologists agreed on the diagnoses in 19/23 cases (kappa value 0.78). They agreed with a less experienced radiologist in 17/23 and 19/23 cases, respectively (kappa values 0.66 and 0.76). Interpretation MRI is a useful tool for demonstration of occult hip fractures. In the absence of a hip fracture, another explanation for the patient’s pain and disability will often be given.

The neuronal regulation of fracture healing: Effects of sciatic nerve resection in rat tibia

The effect of sciatic nerve resection on tibial fracture healing was studied in rats 25 days post-trauma. To prevent differences in loading between sham-operated and nerve-resected animals the fractured limbs were cast-immobilized. On radiograms 8 of 11 fractures in the sham-operated animals showed very little callus formation in contrast to only 1 of 8 fractures in the group with nerve resection. Measured by single-photon absorptiometry, animals with sciatic nerve resection had a higher bone mineral content than the sham-operated animals. However, the mechanical strength in three-point cantilever bending was not better in the nerve-resected rats, implying a defective organization of the large callus. These results suggest neural regulation plays a role in the type of fracture healing, primary or secondary, and in the amount and quality of the callus.

EFFECT OF LIFELONG NICOTINE INHALATION ON BONE MASS AND MECHANICAL PROPERTIES IN FEMALE RAT FEMURS

Abstract. As tobacco smoking has been identified as a risk factor in the development of osteoporosis, possible deleterious effects of nicotine inhalation on bone mineral density (BMD) and mechanical properties of the femur in female rats were studied. Female Sprague Dawley rats were exposed to nicotine vapour 20 hours a day 5 days a week for 2 years. The nicotine concentration in the inhaled air was kept at a level, giving a plasma nicotine concentration exceeding that of heavy smokers. Throughout the study, the nicotine-exposed rats weighed approximately 10% less than the control rats. At the end of the study the rats were anesthesized and blood was collected by heart puncture for determination of nicotine in plasma. Both femurs were resected and scanned by dual X-ray absorptiometry (DXA). There was no difference in BMD between control rats (n = 7) and nicotine-exposed rats (n = 23) (mean 0.216 ± 0.021 g/cm2 and 0.210 ± 0.014 g/cm2, respectively (P= 0.19)). The left femur was used for mechanical testing of the shaft and the neck. No significant difference could be demonstrated in ultimate bending moment, ultimate energy absorbtion, stiffness, or deflection between the two groups. In conclusion, no negative effects of nicotine inhalation on the femurs of female rats were found.