Tissue engineering solutions for traumatic bone loss

Tissue engineering strategies for the repair, replacement, or augmentation of bone defects involves the use of cells, matrices, and bioregulatory factors. The source (endogenous, exogenous) and character of these factors, however, may vary greatly among the many approaches taken by current investigators. Although the results of current tissue engineering methods for regenerating bone have shown great promise, the extent of damage to extremities associated with war injuries may require the development of techniques that differ substantially from current practice.

Study of recombinant human osteogenic protein-1 expressed in prokaryocyte on the repair of extracted socket in rabbits

The study investigated the effect of recombinant human osteogenic protein-1 (rhOP-1) expressed in prokaryocyte, to promote the healing of alveolar socket. A model of rabbit extracted socket into which the composites of rhOP-1 and gelatin sponge was immediately implanted was created and the osteoinduction of rhOP-1 was assessed by histological method, quantitative measurement of calcium content and alkaline phosphatase (ALP) activity. The result of histology showed that bone healing in rhOP-1 side is 4-6 weeks earlier than that of the control side. ALP activity and calcium content in rhOP-1 side were significantly high compared with that of the control side. rhOP-1 has a satisfactory osteoinduction ability to promote the healing of extracted socket.

Closed antegrade interlocked nailing of femoral shaft fractures operated up to 2 weeks postinjury in the absence of a fracture table or C-arm

BACKGROUND

We present our technique of closed nailing in diaphyseal femoral fractures treated between 1 to 14 days postinjury. The purpose of the study was to demonstrate the fact that such fractures can be treated closed in the absence of a fracture table or C-arm.

METHODS

In all, 200 consecutive closed femoral fractures were fixed 1 to 14 days postinjury during a period of 2 years. Skeletal traction was applied immediately at admission and sufficient weight was applied to overcome muscle spasm. In most cases, a closed nailing was successfully performed. Distal locking was achieved with either a medinov nail with wings for distal locking, or a standard nail with a jig for the distal lock.

RESULTS

The average age of the patients was 30 years. Follow up ranged from 6 to 12 months. Mean duration of follow up was 10 months. All patients had a functional range of movement at the hip and knee with a normal gait. The average time taken for surgery was 90 minutes with an average blood loss of 50 to 100 mL. Time in hospital after surgery was 2 to 10 days.

CONCLUSIONS

Delayed closed nailing of femoral fractures can be achieved without a C-arm or a fracture table provided adequate skeletal traction is applied preoperatively and proper attention is paid to the surgical steps as described.

[Preparation of gentamicin-impregnated bone allograft and experimental study on treatment of infective bone defect]

OBJECTIVE

To study and prepare a new kind of bone graft, which has osteogenesis, local anti-infective function and low immunogenicity.

METHODS

Gentamicin-impregnated bone was prepared by means of ultrasonic and vacuum, the release of gentamicin in vivo was measured by inhibition bacteria. Ten healthy male adult sheep were made animal infection models of thigh bone or humerus defect of 6 mm x 6 mm x 20 mm at size, and the defect was inoculated into 1 ml 5 x 10(10) CFU/ml Staphylococcus aureus. The animals were randomly divided into the experimental group (n=5, the bone graft with gentamicin was implanted) and the control group (n=5, the bone graft without gentamicin). Macroscopic, WBC count, radiological, and histological investigations were carried out to evaluate the anti-infective and osteosis capability.

RESULTS

The concentrations of gentamicin were 46.1 microg/ml in bone allograft and 17.3 microg/ml in muscles after 1 day. The concentrations of gentamicin exceeding the minimum inhibitory concentration lasted for 14 days in vivo. WBC in the control group was higher than that in the experimental group. In the control group, 1 case died owing to septicemia 3 weeks after operation. The implanted bones were wrapped in pus 4 and 6 weeks, and the defects were filled with fibre tissue 8 and 10 weeks after operation. In the experimental group, 1 case was infected, the others had a good concrescence. The bone allografts began to integrate with adjacent bone after 4-8 weeks and integrate well after 12 weeks. The X-ray and histological observation showed that new bone formed and took the place of bone allograft.

CONCLUSION

The gentamicin-impregnated bone allograft was of a good sustained release feature in vivo, local anti-infection and osteogenesis. It might be an ideal bone grafting material for bone defects with infection.

Case reports: management of large segmental tibial defects using a cylindrical mesh cage

We report a case series of three patients who sustained open Gustilo-Anderson Type IIIB tibia fractures associated with extensive segmental bone and soft tissue loss. The patients initially were treated with serial wound irrigations, débridements, and external fixation. After the soft tissue envelope was reconstructed successfully, each large segmental bone defect was reconstructed with a cylindrical titanium mesh cage packed with a composite of cancellous allograft and demineralized bone matrix putty and stabilized with a statically locked intramedullary nail. The mean segmental bone loss was 12.2 cm, and all patients had a minimum 1-year followup. One year after reconstruction, radiographs showed stable, well-aligned, healed constructs, and computed tomography images verified the presence of bony ingrowth throughout the cages. All patients were able to ambulate with full weightbearing, and had good ipsilateral knee, hip, and ankle range of motion. This technique seems to be a reasonable alternative for treating large segmental tibial bone defects.

Effect of calcium phosphate glass on bone formation in calvarial defects of Sprague-Dawley rats

The purpose of this study was to investigate the bone regenerative effect of calcium phosphate glass in vivo. We prepared two different sizes of calcium phosphate glass powder using the system CaO-CaF2-P2O5-MgO-ZnO; the particle size of the powders were 400 microm and 40 microm. 8 mm calvarial critical-sized defects were created in 60 male Sprague-Dawley rats. The animals were divided into 3 groups of 20 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As controls, the defect was left empty. The rats were sacrificed 2 or 8 weeks after postsurgery, and the results were evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the bigger powders with 400 microm particle were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 week. When smaller powders with 40 microm particle were transplanted, new bone formation was even lower than the control group due to a lot of inflammatory cell infiltration. It was concluded that the prepared calcium phosphate glass enhanced the new bone formation in the calvarial defect of Sprague-Dawley rats and it is expected to be a good potential materials for hard tissue regeneration. The particle size of the calcium phosphate was crucial; 400 microm particles promoted new bone formation, while 40 microm particles inhibited it because of severe inflammation.

[Complications in complex fractures of the tibial plateau and associated factors]

BACKGROUND

We undertook this study to identify factors associated with surgical complications of complex fractures of the tibial plateau.

METHODS

We designed a case-control study with 56 patients with a diagnosis of complex fracture in the tibial plateau (IV-VI Schatzker) and with 12.9 +/- 3.2 (8-18) months of follow-up. Risk factor exposure was defined as having one or more of the following characteristics: age >60 years; co-morbidity (diabetes mellitus, systemic arterial hypertension); time of "Kidde" (>60, >90, >120 min) and fracture type IV, V or VI. A case was considered with one or more complications.

RESULTS

Mean age was 50.1 +/- 15.7 (17-87) years old; 35 patients (62.5%) were males. Homogeneity between groups was shown for age, sex, side effects, type of fracture and time of follow-up; 41.1% of patients had pathological history. All surgeries used pneumatic compression (Kidde) for 91 +/- 27.2 (40-175) min. The implants used were plate plus cancellous screws (53.6%), external fixators plus cancellous screws (35.7%), double plate and intramedullary nail. Complications appeared in 37.5% of all patients. Complications reported were superficial infection (16.1%), residual angular deformities (10.7%, varum [7.1%]), peroneal nerve injury (5.4%), non-union (3.5%) and deep venous thrombosis (1.8%); 22.2% of all patients presented more than one complication.

CONCLUSIONS

Statistically significant risk factors were age >60 years and pneumatic compression >120 min. Patients with one of these characteristics had a three-times risk of complications. No association was demonstrated between type of fracture, surgical treatment, time between injury and the surgery, with development of complications.

A method for vibrational assessment of cortical bone

Large bones from many anatomical locations of the human skeleton consist of an outer shaft (cortex) surrounding a highly porous internal region (trabecular bone) whose structure is reminiscent of a disordered cubic network. Age related degradation of cortical and trabecular bone takes different forms. Trabecular bone weakens primarily by loss of connectivity of the porous network, and recent studies have shown that vibrational response can be used to obtain reliable estimates for loss of its strength. In contrast, cortical bone degrades via the accumulation of long fractures and changes in the level of mineralization of the bone tissue. In this paper, we model cortical bone by an initially solid specimen with uniform density to which long fractures are introduced; we find that, as in the case of trabecular bone, vibrational assessment provides more reliable estimates of residual strength in cortical bone than is possible using measurements of density or porosity.

Non-union of the clavicle and delayed union of the proximal fifth metatarsal treated with low-intensity pulsed ultrasound in two soccer players

Operative treatment has become the treatment of choice in athletes and active patients in non-union of the clavicle and delayed union of the proximal fifth metatarsal. The purpose of this study was to review the short- and long-term clinical results of low-intensity pulsed ultrasound treatment in a non-union of the clavicle and in a delayed union of the proximal fifth metatarsal in 2 elite soccer players. In both patients, the treatment sessions were performed with an ultrasound signal that was composed of a burst width of 200+/-10% mus containing 1.5+/-5% MHz sine waves, with a repeating rate of 1+/-10% kHz and a spatial average temporal intensity of 30+/-30% mW/cm2. The application of the ultrasound was performed by the patients at home for 20 min/day for 3 months. The healing of the non-union of the clavicle was followed by MR imaging and of the delayed union of the proximal fifth metatarsal by radiographs. In both of the cases the end-results were excellent and the players could continue playing at the highest level. The ultrasound method was successful and afforded players a quick return to sport activity.

Tibial plafond fractures treated by articulated external fixation: a randomized trial of postoperative motion versus nonmotion

OBJECTIVES

Assess whether postoperative ankle motion after fixation of a fracture of the tibial plafond, treated with articulated external fixation, leads to a better outcome when compared with similar treatment without postoperative ankle motion.

DESIGN

Multicenter randomized trial.

SETTING

Three Level I trauma centers.

PATIENTS/PARTICIPANTS

Fifty-five patients were enrolled and entered into a Web-based database and randomized into 1 of 2 groups. Forty-one patients were evaluated at a 1-year follow-up visit, and 31 were seen at 2 years or longer after injury.

INTERVENTION

Patients were treated with a hinged external fixator and limited internal fixation of the articular surface. They were divided postoperatively into two groups, 1 of which had a locked hinge and the other had a mobile hinge and a motion protocol.

MAIN OUTCOME MEASUREMENTS

A general health status questionnaire, the SF-36 (short-form 36); a joint-specific ankle questionnaire, the Ankle Osteoarthritis Score (AOS); and range of motion (ROM) of the ankle joint.

RESULTS

There were no significant differences between the two groups at either follow-up interval in the ankle ROM measurement, the AOS pain and disability scale, or the SF-36 physical component summary (PCS) and mental component summary (MCS) scales.

CONCLUSIONS

These results indicate that treatment protocols that use long periods of cross-joint external fixation that immobilizes the ankle as definitive treatment result in similar patient outcomes compared to otherwise identical treatment protocols that incorporate and use an articulated hinge for ankle motion. However, the results should be interpreted with caution because the patient numbers were too small to detect potentially meaningful differences in outcomes and the follow-up was too short to assess for differences in the development of arthrosis.

Displaced femoral neck fatigue fractures in military recruits

BACKGROUND

Displaced fatigue fractures of the femoral neck are uncommon, but they can lead to substantial patient morbidity. This study was performed to examine the incidence, long-term consequences, radiographic findings, risk factors, and complications associated with this fracture.

METHODS

Between 1975 and 1994, twenty-one military recruits sustained a displaced fatigue fracture of the femoral neck. Nineteen patients were followed for an average of eighteen years. Data regarding the population at risk, hospital records, initial and follow-up radiographs, and physical findings were analyzed. The impact of instructions from the Finnish Defense Forces, Department of Medical Services, provided in 1986 for prevention of femoral neck fatigue fractures was assessed.

RESULTS

At our institution, the incidence of displaced fatigue fractures of the femoral neck was 5.3/100,000 service years from 1975 to 1986, prior to the introduction of the prevention regimen in 1986, and it was 2.3/100,000 service years (95% confidence interval, 0.11 to 1.31) from 1987 to 1994. The rate of Garden type-IV fractures decreased from 3.8 to 0/100,000 service years (95% confidence interval, 0 to 0.66) between the first and second time-periods. The detection of nondisplaced symptomatic fatigue fractures of the femoral neck increased from 15.5 to 53.2/100,000 service years (95% confidence interval, 2.27 to 5.21) between the two time-periods. Eighteen of the nineteen patients had had prodromal symptoms prior to the fracture displacement. Following fracture treatment, six patients had delayed union or nonunion of the fracture. Osteonecrosis of the femoral head developed in six patients and was significantly associated (p = 0.001) with shortening of the femoral neck. Severe osteoarthritis developed in eight patients.

CONCLUSIONS

A displaced fatigue fracture of the femoral neck leads to long-term morbidity in a high percentage of patients. Most patients have prodromal symptoms, which provide an opportunity to prevent fracture displacement. Our results indicate that, in a military setting, an educational program can diminish the incidence of fatigue fracture displacement by increasing the awareness of these fractures and their prodromal symptoms and by facilitating diagnosis in the early stages before displacement occurs.

LEVEL OF EVIDENCE

Therapeutic Level III.

Locked intramedullary nailing of metacarpal fractures secondary to gunshot wounds

PURPOSE

To investigate the results of fixation of 10 metacarpal shaft fractures secondary to low-velocity gunshot wounds with locked intramedullary nails.

METHODS

We reviewed the results of 10 patients with locked intramedullary nailing of the metacarpal for low-velocity gunshot wounds. Autogenous bone grafting was used in 9 of the 10 fractures. The follow-up period averaged 26 months. The parameters evaluated included angulation, rotational alignment, shortening of the digit, postoperative metacarpophalangeal (MCP) range of motion, and time to union.

RESULTS

Nine of 10 fractures showed corticocancellous bone autograft incorporation in the midshaft of the metacarpal on radiographs 3 months after surgery; the single fracture without bone grafting did not unite and required an additional procedure with bone grafting to achieve union. The MCP flexion averaged 81 degrees. All MCP joints attained full extension except for 2 that had a 10 degrees extension lag. One metacarpal required an extensor tendon tenolysis and an MCP capsulotomy. No malrotation of the digits was noted and none of the patients developed an infection. The average shortening was 1.2 mm and 1 metacarpal had an angulation of 6 degrees.

CONCLUSIONS

Locked intramedullary nailing of the metacarpal with autogenous iliac crest bone graft is an effective technique for treating low-velocity gunshot metacarpal fractures associated with bone loss and comminution. The locked implant maintains satisfactory alignment, length, and rotation of the metacarpal until graft incorporation and bone healing occurs.

Biomechanical comparison of flexible intramedullary nailing versus crossed Kirschner wire fixation in a canine model of pediatric forearm fractures

This study compares the biomechanical properties of crossed Kirschner wires with those of flexible intramedullary nails in a canine model. The Kirschner wire groups had greater anteroposterior, lateral, and torsional stiffness and force to failure rates in most of the bones tested. Bones fixated with flexible intramedullary nails could bend and recoil during failure testing. The bones fixated with Kirschner wires failed at smaller levels of displacement and frequently had hardware cut-out during failure testing. Flexible intramedullary nails have more recoil and do not induce new fracture lines, which may explain their clinical superiority to Kirschner wires despite providing less rigid fixation.

Abnormal union of mandibular fractures: a review of 84 cases

PURPOSE

The purpose of this study was to investigate the characteristic and contributory factors of mandibular fractures with abnormal union in China, aiming to produce guidelines to facilitate the management of mandibular fractures so that this complication may be avoided.

PATIENTS AND METHODS

In this retrospective review, the records of all patients who were identified as having abnormal union of mandibular fracture in a period of 10 years (October 1994 to October 2004) in our hospital were collected and analyzed for the features of the patients' age, gender, trauma type, fracture site, and type of abnormal union. At the same time, the data about treatment methods, antibiotics use, presence of infection, patients' compliance, patients' systemic disease, and personal habits such as alcohol or drug abuse were explored and analyzed to determine the main cause contributing to the development of abnormal union.

RESULTS

Eighty-four patients met the inclusion criteria and were included in this study, and 31 to 40 years and 21 to 30 years were the common age groups. Traffic accidents were responsible for the majority of abnormal unions. A total of 135 abnormal unions were identified within the 84 patients, and 44 patients suffered more than one abnormal union. Inadequate unions were more frequent than malunions within the 135 abnormal unions, and most of the abnormal unions were in the condyle. The main causes contributing to the development of abnormal union included being untreated (n = 36), inexperience of the surgeon (n = 27) or patient's noncompliance (n = 6) during the process of treatment, and infection (n = 5). In our series, no patient with alcohol or drug abuse was observed.

CONCLUSIONS

The characteristic of abnormal union is associated with patient's age and gender, severity and type of original trauma, and fracture site. In a sense, the development of abnormal unions is related to the social, economic, and cultural factors in China. At present the key problem of decreasing and avoiding mandibular abnormal unions in our country is to perform appropriate treatment methods in time. At the same time, it is important to obtain patients' compliance during the process of treatment and actively prevent infection.

The treatment of unstable metacarpal and phalangeal shaft fractures with flexible nonlocking and locking intramedullary nails

Metacarpal and phalangeal shaft fracture fixation can be achieved by closed IM nailing. This technique provides sufficient stability to commence early unsupported joint motion and minimize soft-tissue irritation and scar formation. Stability is enhanced by proximal nail locking; a measure that extends the indications to spiral and comminuted fractures. The surgical technique is simple but requires attention to detail.

[Treatment of complex acetabular fractures by a modified extended iliofemoral approach]

OBJECTIVE

To evaluate the effect of the modified extended iliofemoral approach on treating complex acetabular fractures.

METHODS

Thirty-six cases of complex acetabular fractures were treated by the open reposition and internal fixation by a modified extended iliofemoral approach.

RESULTS

Thirty-six cases were followed up for 7-46 months, with an average of 23.8 months. According to the Matta standard, anatomical reposition was performed in 24 cases, perfect reposition in 8 cases, and unsatisfactory reposition in 4 cases. By the modified d'Aubigne-postel score, among the 36 cases, 22 had an excellent result, 9 had a good result, and 5 had a poor result.

CONCLUSION

The modified extended iliofemoral approach facilitates the operative exposure of the anterior and posterior walls and both columns of the acetabulum in the surgically-treated acetabular fractures by the open reposition and internal fixation. Because of the reconstruction, the functions of the abductor muscle mass managed by the lag-screw-fixed osteotomies of the iliac crest, and greater trochanter, the patients can achieve a rapid rehabilitation of the joint.

Hook-plate fixation of unstable lateral clavicle fractures: a report on 63 patients

BACKGROUND

Hook-plate fixation of unstable lateral clavicle fractures has given promising results in previous reports, but numbers of patients have been small. We assessed the results of this technique in 63 patients.

PATIENTS AND METHODS

63 patients with unstable lateral clavicle fractures were operated on at Oulu University Hospital during 1997-2004, using a clavicle hook-plate. Fracture union and complications were assessed retrospectively from case records and radiographs. The subjective part of the Constant score, Oxford shoulder questionnaire data and subjective shoulder value (SSV) were assessed after an average of 3.6 years in 58 patients. 31 patients were reviewed at the outpatient clinic, using complete Constant scores and radiographs of both acromioclavicular joints.

RESULTS

59 fractures united uneventfully. There was 1 case of delayed union and 3 nonunions, but only 1 of these required surgery. Additional complications involved 1 case of infection, 1 frozen shoulder and 3 cases of late fracture medial to the plate. The mean Oxford score was 15, the mean for the subjective part of the Constant score was 32, and the SSV was 86%.

INTERPRETATION

Clavicle hook-plate fixation of unstable lateral clavicle fractures results in a good union rate and good shoulder function.

Clinical inquiries. What is the most effective management of acute fractures of the base of the fifth metatarsal?

For acute Jones' fractures in recreationally active patients, early intramedullary screw fixation results in lower failure rates and shorter times to both clinical union and return to sports than non-weightbearing short leg casting (strength of recommendation [SOR]: A, based on 2 randomized controlled trials [RCT]). Non-weightbearing short leg casting achieves union in 56% to 100% of patients but can require prolonged casting (SOR: B, based on 2 prospective cohorts and multiple retrospective, follow-up studies). Stress fractures were not included in this review. For avulsion fractures of the fifth metatarsal tuberosity, a soft Jones' dressing allows earlier return to pre-injury levels of activity than rigid short leg casting (SOR: B, based on a lower-quality RCT).

Syndesmosis fixation: a comparison of three and four cortices of screw fixation without hardware removal

BACKGROUND

Great variability exists in methods of stabilization for syndesmotic disruptions of the ankle. We hypothesized that syndesmotic screw fixation with 3.5-mm fully threaded cortical screws through either three or four cortices would have similar strength and rate of mechanical failure and that retention of screws after fracture healing would not result in adverse clinical symptoms.

METHODS

In a prospective, surgeon-randomized study at a Level-one trauma center, 127 patients with syndesmotic disruptions were treated surgically. Seven patients were lost to followup, leaving 120 for review. Syndesmotic disruptions were stabilized with 3.5-mm fully threaded cortical screws placed through three or four cortices. Screws were removed only if symptomatic. Outcome criteria were screw failure, loss of reduction, and need for hardware removal.

RESULTS

Fifty-nine patients received fixation through three cortices and 61 patients received fixation through four cortices. Mean follow-up was 150 days. In the group with stabilization through three cortices, hardware failure occurred in five patients (8%) and three had a loss of reduction. In the group with stabilization through four cortices, hardware failure occurred in four patients (7%); all were asymptomatic and did not require screw removal. There was no loss of reduction in that group. Comparing the two groups using binary logistic analysis, there was no difference in loss of reduction (p = 0.871), screw breakage (p = 0.689), or need for hardware removal (p = 0.731).

CONCLUSION

The data suggest that either three or four cortices of fixation can be used when stabilizing syndesmotic injuries of the ankle. There was a trend towards higher loss of reduction in the group with tricortical fixation when weightbearing restrictions were not followed. Retention of the syndesmotic screws, even with mechanical failure, does not pose a clinical problem. Weightbearing can be allowed at 6 to 10 weeks without routine removal of screws.

Mini external fixation for hand fractures and dislocations: The current state of the art

External fixation devices for the hand provide a versatile approach to various hand injuries. Some fractures and dislocations urge the use of an external minifixation; in other fractures, external minifixation must be seen as an alternative or companion to other methods of hand stabilization. MiniFix is useful to maintain or restore hand function and hand anatomy.

Low-intensity pulsed ultrasound accelerates bone-tendon junction healing: a partial patellectomy model in rabbits

BACKGROUND

Low-intensity pulsed ultrasound has been demonstrated to be beneficial for accelerating fracture healing, delayed union, nonunion, and soft tissue repair.

HYPOTHESIS

Low-intensity pulsed ultrasound accelerates healing of bone-to-tendon junction repair by promoting osteogenesis and tissue remodeling at the healing junction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Standard partial patellectomy was conducted in forty-eight 18-week-old rabbits divided into an ultrasound treatment and control group. Daily ultrasound was delivered 3 days after surgery onto the patellar tendon-patella healing junction and continuously up to weeks 2, 4, 8, and 16 postoperatively, when the patella-patellar tendon complexes were harvested for radiographic, histologic, and biomechanical evaluations.

RESULTS

Radiographic measurements showed significantly more newly formed bone at the patellar tendon-patella healing junction in the ultrasound group compared with the controls at week 8 (4.91 +/- 2.74 mm(2) vs 2.50 +/- 1.83 mm(2), P < .05) and week 16 (7.22 +/- 2.34 mm(2) vs 4.61 +/- 2.22 mm(2), P < .05) after partial patellectomy. Histologically, the ultrasound group at weeks 8 and 16 showed improved tissue integration, characterized by trabecular bone expansion from the remaining patella and regeneration of fibrocartilage layer at the patellar tendon-patella healing junction. Fluorescence microscopy revealed earlier bone formation in the ultrasound group when compared with the controls at week 8 (1.78 +/- 0.32 vs 1.23 +/- 0.43, P < .01) and week 16 (2.10 +/- 0.67 vs 1.29 +/- 0.35, P < .01). Mechanical testing showed significantly higher failure load and ultimate strength in the ultrasound group (300.2 +/- 61.7 N and 7.10 +/- 1.29 MPa, respectively) as compared with controls (222.3 +/- 65.1 N and 5.26 +/- 1.36 MPa, respectively) at week 16 (P < .05 for both).

CONCLUSION

Low-intensity pulsed ultrasound was able to accelerate bone-to-tendon junction repair.

CLINICAL RELEVANCE

These results may help establish treatment efficacy for accelerating bone-to-tendon junction repair and facilitating earlier rehabilitation.

Stress fractures in adolescent competitive athletes with open physis

There have been no studies devoted exclusively to stress fractures in competitive athletes with immature skeletal systems so far. The object of this case series was to describe special features of stress fractures in athletes with immature skeletal systems, with special reference to sport-specific strain, diagnosis and treatment results. The study population was made up of 19 children and adolescents with a total of 21 stress fractures. The average observation period was 4.83 years [standard deviation (SD) 2.69] and the average age at diagnosis, 14.04 years (SD 4.7). The lower extremity was affected in most of our cases. In adolescent athletes, endurance sports appear to lead preferentially to stress fractures in the region of the metatarsal bones, while sports requiring sudden stops at high speed appear to increase the risk of fractures in the region of the tibial diaphysis (P=0.0322). Most (20 of 21) of the fractures in this study were treated conservatively with refraining from athletic activity and reduction of stress/weight-bearing for an average of 6.73 weeks (SD 2.91). In five cases the extremity was in addition immobilized in a plaster cast for 5.32 weeks (SD 2.21). Complete healing was achieved in 14 cases. In seven cases, however, the treatment did not lead to a satisfactory outcome. Most of the patients whose symptoms persisted over a long period had fractures in the tibia and were engaged in sports requiring frequent sudden stops. Our data suggest that stress fractures in athletes, whose skeletal systems are still immature, lead to a clinical picture that does not always culminate in a good outcome of treatment. We therefore recommend a thorough and early diagnostic investigation (including MRI) and consistent treatment whenever a patient's history and clinical picture give any indication that a stress fracture might be present.

Extracorporeal shock wave treatment for defective nonunion of the radius: a rabbit model

PURPOSE

To investigate the effect of extracorporeal shock wave treatment (ESWT) on bony union using volume analysis of the callus mass by computed tomography and histology.

METHODS

Both radii of 13 rabbits were osteotomised and a defective bony nonunion created by placing a polyethylene pad between the osteotomy site for 40 days. Nonunion was confirmed by radiography using Lane-Sandhu criteria. ESWT (14 kW, 0.46 mJ/mm(2), 1000 shock waves) was applied to the right radius of the rabbits. The left radius served as a control. Five rabbits were killed 4 weeks after ESWT (group 1) and 8 after 6 weeks (group 2). Volume analysis of the callus mass was performed using computed tomography and the bone healing process was assessed by histology.

RESULTS

In group 1, callus volume on the treated side was invariably greater than that on the control side; the difference being statistically significant (p=0.032). In group 2, the callus volume of the treated side was greater than that of the control side, except in rabbits 4 and 9. Only after excluding the findings from the latter did the difference attain statistical significance (p=0.020). Histology confirmed that the bone-healing process was faster in the treated side.

CONCLUSION

ESWT enhanced the bone-healing process by increasing both volume and speed of callus formation.

Primary internal fixation and bone grafting for open fractures of the hand

Primary bone grafting and internal fixation is a reliable option for the treatment of segmental hand defects resulting from high-energy crush or avulsion injuries. Immediate reconstruction can be performed safely if radical debridement and adequate soft tissue coverage of bone can be achieved. When these two criteria cannot be met, staged reconstruction should be performed. The low infection rate (0%), the high union rate (92%), and the return to full, unrestricted, previous employment for all patients in the authors' series supports the use of primary bone grafting in an acute setting. This single-stage approach to fracture management also permits earlier and more aggressive hand therapy that, in turn, can lower the high functional morbidity so often associated with these injuries.