We undertook a prospective study in 51 male patients aged between 17 and 27 years to ascertain whether immobilisation after primary traumatic anterior dislocation of the shoulder in external rotation was more effective than immobilisation in internal rotation in preventing recurrent dislocation in a physically active population.

Of the 51 patients, 24 were randomised to be treated by a traditional brace in internal rotation and 27 were immobilised in external rotation of 15° to 20°. After immobilisation, the patients undertook a standard regime of physiotherapy and were then assessed clinically for evidence of instability. When reviewed at a mean of 33.4 months (24 to 48) ten from the external rotation group (37%) and ten from the internal rotation group (41.7%) had sustained a futher dislocation. There was no statistically significant difference (p = 0.74) between the groups.

Our findings show that external rotation bracing may not be as effective as previously reported in preventing recurrent anterior dislocation of the shoulder.

Purpose: Fracture reduction (FR) during intra-medullary nailing of long bone fractures requires an extensive use of fluoroscopic radiation. Fluoroscopy based navigation system using custom FR software is introduced of which the main advantage is its ability to track simultaneously the two fracture segments during fracture reduction. The aim of this study was to test the feasibility of this system.

Methods: 26 Patients 17 males and 7 females suffering from 10 tibial shaft and 14 femoral shaft fracture were operated using the FR software. Two trackers were attached to each of the main fracture segments. Image registration was done by acquiring fluoroscopic images including the fracture site and the two metaphysial areas of the long bone on both perpendicular planes. The system uses two cylinder models representing the fracture segments, each defined between two points chosen by the surgeon on the acquired images, these are tracked by the system. Fracture reduction was qualitatively evaluated as well as other features of the system. Overall radiation was registered.

Results: A small number (< 10) of flouroscopic images was acquired; this decreased as we gained more experience. FR software was helpful in all the cases and accomplished good and quick reduction; it reduced the need for added radiation to 2–4 verification images.

The system was utilized as well in all cases for choosing the nail point of entry, in 7 (25%) for blocking screws planning and in 4 (16%) for nail locking successfully.

Conclusion: The FR software enabled and improved significantly the performance of this surgical task with a dramatic decrease in radiation and FR time. The software still lacks the fine tuning needed for best performance.

Introduction: Cigarette smoking is associated with musculoskeletal degenerative disorders and increased risk of fracture delayed- and non-union. A lower-than-average concentration of mesenchymal stem cells may be the reason for the reduced regenerative potential. The aim of this study was to compare the concentration of bone marrow MSC of smokers and non-smokers.

Methods: As part of a larger IRB approved clinical trial, 20ml bone marrow samples were processed and MSC were isolated. FACS analysis was used both to assess the purity of the separation process and to evaluate the number of MSC recovered from each sample. Differences in continuous outcomes between smoking and non-smoking groups were assessed by two tailed t test and difference between categorical outcomes was measured by chi square test.

Results: Twenty six subjects participated in the study. Thirteen were smokers and thirteen were non-smokers. Groups were not significantly different with regard to age and gender. The average concentration of MSC was 352.04x10³/ml for non smokers and 131.23x10³/ml for smokers (SD’s were 245.72 x10³/ml and 161.54 x10³/ ml respectively. The difference between the smokers and nonsmokers was significant (t=3.2 p=0.004).

Discussion: The present study indicates that cigarette smokers have lower-than-average concentration of MSC in their bone marrow. Since MSC are a key element in every regenerative process of the musculoskeletal system, our findings may contribute to understanding and prevention of delayed and non-union. Further investigation is undertaken to address the issue of bone marrow recovery after smoking cessation.

Introduction: Preliminary data suggest that immobilization in external rotation may be effective in lowering the incidence of recurrence after first traumatic shoulder dislocation, with a zero reoccurrence rate reported at 15 months follow-up. The purpose of the present study was to ascertain whether this method could lower the incidence of recurrent dislocation in a young, very physically active population.

Methods: In an IRB approved prospective study, young males who sustained first traumatic shoulder dislocation were randomized to be treated for four weeks either using a traditional internal rotation brace or a new device which immobilizes the shoulder at 15 to 20 degrees of external rotation. Subjects were then treated according to a standard physical therapy protocol. Follow-up was done at five time points in the first year post dislocation. Subjects with clinically stable shoulders resumed full activity after three months. Differences in outcome were assessed by the chi square test.

Results: Thirty nine subjects participated in the study. Thirty of them were soldiers. Twenty four subjects were treated with external rotation braces. At follow-up of between 4 to 28 months, a new dislocation was documented in 8 of the 24 subjects immobilized in external rotation (33%) and in 5 of the 15 subjects immobilized in internal rotation (33 %). No statistical difference (p=1.0) was found between the instability rates of the two treatment groups.

Discussion: The present study indicates that even in a short-term follow-up the technique of immobilizing a first dislocation in external rotation was not effective in lowering the incidence of recurrent shoulder dislocations in a young, physically active population.

Bone regeneration is a complicate biological process of the skeletal system leading to restoration of the limb function. This process becomes more challenging in a case of critical size defect (CSD) which defined as the smallest defect caused by infection, tumor or trauma that will not heal spontaneously.

A previous study in our lab tested the usage of encapsulating Ethyl Cellulose (Hercules Inc, Wilmington, Del) membrane in CSD as compared to control (no-membrane). The study demonstrated that bone healing was more sufficient in limbs coated with the membrane than the control limbs. Additional approach to the treatment of bone deficiency is the use of multi-potent mesenchymal stem cells (MSC) that are brought into the bone defect in order to induce bone formation.

The objective of this study was to investigate a new polymer formulation in order to produce the best environmental support for adhesion, proliferation and differentiation of MSC.

In this study we found out that with the usage of Polyvinylacetate, PMMC R and PMMC L in PMMC RL PEG 400 [15%], MSC had similar characters to the polystyrene ( a well known ideal platform for MSC). This positive result permitted apparently thanks to creation abilities of:

Hydrogen-bonds between MSC and the partial negative charge on the carboxyl group as well as on the oxygens of the plasticizer that is intertwined within the membrane monomers.

In summary, we have only started to reveal the remarkable potential of using MSC, and there are still many obstacles to overcome. However, applying the findings from this study, namely inserting a membrane coated with MSC into a CSD may become a true biological treatment option.

Introduction: Cell-based strategies for regeneration and reconstitution of musculoskeletal tissues are gaining interest. The difficulty in obtaining the required amount of mesenchymal stem cells (MSC) stems from their scarcity and the time needed to grow them in culture. We developed a rapid and efficient method to isolate MSC from bone marrow aspirate based on their surface markers, as a platform for future cell based therapy.

Methods: Bone marrow was aspirated from the iliac crest of fifteen adult subjects undergoing surgeries involving this bone. 15 ml samples were obtained, fractionated for mononuclear cells and then subjected to immunomagnetic isolation using microbeads of directly conjugated mouse anti–human CD105 antibodies. Recovered cell fraction was analyzed for phenotype and functional parameters.

Results: The samples yielded an average of 14.6±2.5x10⁶ mononuclear cells per ml. Of these, fraction of CD105 positive cells consisted of 2.3±0.45%, which accounts for 0.25±0.06x10⁶ cells per ml. Post isolation analysis shows that 79±3.2% were positively stained for CD105 and 36±5.8% stained positive for CD45. These cells generated 6.3±1.4 Colony Forming Units (CFU) per 10⁵ cells. MSC concentration is higher in males and lower in smokers. Processing time is approximately 3 hours.

Discussion and Conclusion: Regeneration of mesenchymal tissues using progenitor cells with appropriate matrix and signals was shown feasible, however large numbers of these rare cells are needed. An effective and safe method for purification of autologous MSC enables us to avoid the risks and the time span associated with culture expansion. We conclude that this method is both effective and rapid.

Introduction: Necrotizing Fasciitis (NF) is a potentially lethal deep soft tissue infection. Correlation between prompt diagnosis and adequate surgical treatment and favorable outcome is well documented, however scarcity of specific cutaneous signs and the potential of evolution from otherwise simple infections may contribute to delay in diagnosis and treatment. Few clues may assist the physician to avoid overlooking this surgical emergency.

Patients and Methods: Sixty-eight patients were treated in our hospital for necrotizing fasciitis since 1990. In twenty-five of them the major involvement was peripheral, sparing the head, neck and torso. We reviewed these 25 cases for patterns of presentation and alarming signs for the first encountered physician, as well as for kinetics of treatment and outcome.

Results: Eight female and seventeen male patients aged 1–83 (average 53.6) years were treated. Only eight of them (32%) were free of comorbidities associated with reduced immunity. Majority of patients referred to the emergency department complaining of local pain/tenderness and erythema for few days accompanied by excruciating pain. Vital signs were often within normal limits, although leucocytosis on admission was common and gas was evident in the soft tissue by imaging. Surgical debridement was usually carried out on the day of diagnosis that was established immediately on admission in 10 cases (40%) but was delayed beyond 72 hours in seven patients (28%). CT scans showed severe edema and muscle liquefaction when taken. Thighs and gluteal region was the most common site of infection (56%) and cultures grew gram positive cocci (64%) and enteral flora (68%) in mono- and poly-microbial cultures. Only three cultures grew unaerobes, of which only one was clostridium. Accordingly, imaging studies showing gas in the soft tissue were uncommon. Eight patients (32%) have expired, and the average hospitalization period was over 38 days for the survivors.

Conclusions: NF is one of the surgical emergencies encountered by orthopedic surgeons. It is there, knocking at our door and will not go away… even a minor delay in diagnosis may be catastrophic to the patient, who often present with common signs and symptoms of mild to moderate skin infection. It should therefore be noted that pain inadequate for a minor infection was characteristic to most patients diagnosed with NF, and that CT findings may establish the diagnosis. Although considered pathognomonic, both crepitus and imaging finding of gas in the soft tissue are uncommon. Special attention to patients at risk and careful physical examination may lead to rapid diagnosis and treatment, and eventually lower the significant morbidity and mortality associated with this condition.

Introduction: Fluoroscopy is routinely used for real-time intra-operative localization of patient anatomy and surgical instrument positioning. Using this radiographic information the orthopedic surgeon inserts different implants into bone. Despite its utility, however, fluoroscopy does have disadvantages. The most notable is potential occupational radiation exposure. Conventional fluoroscopy usually provides only one plane at a time, whereas at least two planes are needed for optimal placement of an implant. By combining a standard C-arm fluoroscopy with computer aided surgical technology, radiation exposure can be eliminated and four different planes can be visualized simultaneously. This study presents data of preliminary clinical experience using this new technology.

Material and methods: The Stealth Station Treatment Guidance Platform System by Medtronic was used. The calibration target was attached to a C-arm fluoroscope. The static reference arc which was attached to the patient and various surgical tools. All with affixed light emitting diodes (LEDs) which were seen by the Infra Red camera. After a short registration process in which the relevant anatomy images were acquired, the C-arm was withdrawn and the entry point to the operated anatomy was determined using the navigation capabilities of the system.

During a period of six months, 31 patients underwent different surgical procedures in which a guided wire was used for: percutaneous fixation of unstable pelvis and hip fractures (13 patients), inserting and locking of an intrameduallry nail (12 patients), inserting pedicular screws (2 patients), or removing foreign-bodies or internal fixations (4 patients). In all cases the placement of the hardware was approved by conventional fluoroscopy as well.

Results: Excellent correlation between the virtual fluoroscopic imaging and live fluoroscopy was observed, thus the placement of the wire in all cases was satisfactory and there was no need to change the position of the wire following the live fluoroscopic confirmation. The number of fluoroscopic buttoning was smaller than the average number in similar surgery using conventional fluoroscopy.

Discussion: According to our preliminary clinical experience it seems that virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. Our impression is that its saves fluoroscopic radiation exposure and improves exactness of the procedure. However, since currently only one reference arc can be detected at a time by the guidance system it can be used only in a stable anatomical situations (such as non-displaced fractures or pedicular screw placements). The use of better-oriented surgical instrumentation and more than one reference point detection will significantly improve the clinical potential of this method.

Introduction: Fluoroscopy is routinely used for real-time intra-operative localization of patient anatomy and surgical instrument positioning. Using this radiographic information the orthopedic surgeon inserts different implants into bone. Despite its utility, however, fluoroscopy does have disadvantages. The most notable is potential occupational radiation exposure. Conventional fluoroscopy usually provides only one plane at a time, whereas at least two planes are needed for optimal placement of an implant. By combining a standard C-arm fluoroscopy with computer aided surgical technology, radiation exposure can be eliminated and four different planes can be visualized simultaneously. This study presents data of preliminary clinical experience using this new technology.

Material and methods: The Stealth Station Treatment Guidance Platform System by Medtronic was used. The calibration target was attached to a C-arm fluoroscope. The static reference arc which was attached to the patient and various surgical tools. All with affixed light emitting diodes (LEDs) which were seen by the Infra Red camera. After a short registration process in which the relevant anatomy images were acquired, the C-arm was withdrawn and the entry point to the operated anatomy was determined using the navigation capabilities of the system.

During a period of six months, 31 patients underwent different surgical procedures in which a guided wire was used for: percutaneous fixation of unstable pelvis and hip fractures (13 patients), inserting and locking of an intrameduallry nail (12 patients), inserting pedicular screws (2 patients), or removing foreign-bodies or internal fixations (4 patients). In all cases the placement of the hardware was approved by conventional fluoroscopy as well.

Results: Excellent correlation between the virtual fluoroscopic imaging and live fluoroscopy was observed, thus the placement of the wire in all cases was satisfactory and there was no need to change the position of the wire following the live fluoroscopic confirmation. The number of fluoroscopic buttoning was smaller than the average number in similar surgery using conventional fluoroscopy.

Discussion: According to our preliminary clinical experience it seems that virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. Our impression is that its saves fluoroscopic radiation exposure and improves exactness of the procedure. However, since currently only one reference arc can be detected at a time by the guidance system it can be used only in a stable anatomical situations (such as non-displaced fractures or pedicular screw placements). The use of better-oriented surgical instrumentation and more than one reference point detection will significantly improve the clinical potential of this method.