Langdon A. Hartsock

Precision extruding deposition (PED) fabrication of polycaprolactone (PCL) scaffolds for bone tissue engineering

Bone tissue engineering is an emerging field providing viable substitutes for bone regeneration. Recent advances have allowed scientists and engineers to develop scaffolds for guided bone growth. However, success requires scaffolds to have specific macroscopic geometries and internal architectures conducive to biological and biophysical functions. Freeform fabrication provides an effective process tool to manufacture three-dimensional porous scaffolds with complex shapes and designed properties. A novel precision extruding deposition (PED) technique was developed to fabricate polycaprolactone (PCL) scaffolds. It was possible to manufacture scaffolds with a controlled pore size of 350 microm with designed structural orientations using this method. The scaffold morphology, internal micro-architecture and mechanical properties were evaluated using scanning electron microscopy (SEM), micro-computed tomography (micro-CT) and mechanical testing, respectively. An in vitro cell-scaffold interaction study was carried out using primary fetal bovine osteoblasts. Specifically, the cell proliferation and differentiation was evaluated by Alamar Blue assay for cell metabolic activity, alkaline phosphatase activity and osteoblast production of calcium. An in vivo study was performed on nude mice to determine the capability of osteoblast-seeded PCL to induce osteogenesis. Each scaffold was implanted subcutaneously in nude mice and, following sacrifice, was explanted at one of a series of time intervals. The explants were then evaluated histologically for possible areas of osseointegration. Microscopy and radiological examination showed multiple areas of osseous ingrowth suggesting that the osteoblast-seeded PCL scaffolds evoke osteogenesis in vivo. These studies demonstrated the viability of the PED process to fabricate PCL scaffolds having the necessary mechanical properties, structural integrity, and controlled pore size and interconnectivity desired for bone tissue engineering.

SHOULDER HEMIARTHROPLASTY FOR PROXIMAL HUMERAL FRACTURES

Shoulder hemiarthroplasty is a well-accepted surgical procedure for the treatment of specific subtypes of proximal humeral fractures, including four-part fractures, three-part fractures associated with severe osteopenia, head-splitting and severe articular impression fractures. Careful patient assessment and meticulous surgical technique are essential to prevent complications. The results are satisfactory in approximately 80% of cases. The results are better in younger patients and in acute versus chronic fractures. There are a significant number of complications that are related to technical details of the procedure. Careful placement of the prosthesis and secure reattachment of the tuberosities to the shaft reduce the chance of complication following surgery. Good to excellent results in terms of range of motion and pain relief can be expected in most patients.

Tibiotalocalcaneal Fusion Using the Hindfoot Arthrodesis Nail A Multicenter Study

Background: Tibiotalocalcaneal arthrodesis is a salvage option for severe ankle and hindfoot deformities, arthritis of the ankle and subtalar joints, avascular necrosis of the talus, failed total ankle arthroplasty, and Charcot arthropathy. This multicenter study reports clinical experience with the hindfoot arthrodesis nail (HAN) in the treatment of patients with severe ankle and foot abnormalities. Methods: Seven participating clinics from Europe and North America recruited 38 patients who underwent ankle/subtalar arthrodesis using retrograde nailing with the HAN. Information was collected regarding technical details, complications, and functional and quality of life outcomes (Short Form-36 [SF-36], American Academy of Orthopaedic Surgeons—Foot and Ankle Outcomes [AAOS-FAO], and numeric rating scale [NRS] for pain) after an average of 2 years of follow-up. Results: The rate of superficial wound infection was 2.4%. No deep soft tissue or bone infections were reported. The overall union rate was 84%. At the time of follow-up, low pain levels were reported, with a mean NRS of 2.2; the mean AAOS-FAO score was 38; and the SF-36 mean physical and mental health component scores were 41.2 and 52.5, respectively. All 13 patients who were unable to work prior to surgery were able to fully return to work. Conclusions: The HAN offered a safe and reliable salvage option for tibiotalocalcaneal arthrodesis in patients with severe ankle and hindfoot disease. It achieved acceptable functional outcome and low complication rates despite the challenging patient cohort. A considerable socioeconomic benefit appeared to result based on the high proportion of patients who were able to return to work postoperatively. Level of Evidence: Level IV, retrospective case series.

FRACTURES ABOUT THE SHOULDER: Conservative Management

Fractures about the shoulder are a frequent occurrence. The clavicle and the proximal humerus are fractured much more often than the scapula. Appropriate diagnosis of these injuries and any associated injuries is essential. The vast majority of these fractures may be treated conservatively with good functional results.

Ankle Arthrodesis Using Anatomically Contoured Anterior Plate

Background: More than 40 fusion techniques for the ankle joint have been reported. The purpose of this retrospective study was to review our preliminary clinical and radiographic results using an anatomically contoured anterior plate for ankle arthrodesis. Materials and Methods: Ten ankle arthrodeses with an anatomically contoured anterior plate performed by a single surgeon were reviewed with an average of 14 months followup. One underwent revision surgery due to screw loosening by reapplying the same plate. Plain radiographs were taken to help determine the stability of fixation and time of fusion. The AOFAS clinical rating system was applied to evaluate patients preoperatively and postoperatively. Results: Nine of ten patients achieved solid fusion radiographically and clinically at an average of 15 (range, 12 to 22) weeks. Bony healing was achieved after an additional 12 weeks for the patient who underwent revision fusion. There were no postoperative wound problems or infections. All patients reported an improvement in their pain level following successful fusion. Conclusion: The application of an anatomically contoured plate provides many advantages, including less soft tissue disruption by using a single anterior incision, ease of deformity correction, early rehabilitation, and high rate of union. Level of Evidence: IV, Retrospective Case Series

Randomized prospective clinical trial comparing reamer irrigator aspirator (RIA) to standard reaming (SR) in both minimally injured and multiply injured patients with closed femoral shaft fractures treated with reamed intramedullary nailing (IMN)

PURPOSE To investigate whether inflammatory markers are improved among patients with traumatic femur fractures who undergo RIA reamed intramedullary nailing (IMN) prior to fixation when compared to patients treated with standard reamed (SR) IMN. METHODS A prospective, randomized, single-blind trial was conducted on patients who had a closed femoral shaft fracture amenable to reamed IMN. Patients were randomized to undergo IMN with standard reaming or IMN with the RIA in a 1:1 ratio. Patients were stratified by Injury Severity Score (ISS) and by presence or absence of chest injury with AIS > 3. Patients had blood samples and bronchioalveolar lavage samples taken at specified time points pre- and postoperatively. Specimens from SR and RIA cohorts were compared for the presence of IL-2, IL-6, IL-8, TNF, and IL-10 in plasma and IL-1b and IL-8 in bronchioalveolar lavage (BAL) samples to determine the relationship between inflammatory markers and intramedullary reaming. RESULTS Nineteen consecutive patients participated in the study with 9 assigned in the RIA group and 10 in SR group. Significant differences existed for ISS between SR and RIA groups (p=0.04). Bronchial lavage data showed no statistical significant differences when RIA and standard reamers were compared and when ISS >16 and <16 were compared, however there were differences for the bronchial IL-8 change when those with chest injury were compared to those without chest injury. Plasma samples showed a trend towards increased IL-6 and IL-10 levels after reaming consistent with the second hit impact. A trend towards higher levels for IL-6 in the SR group was noted at 24 hours post-operatively whereas the IL-10 levels at the post-reaming time point were higher in the RIA group. CONCLUSIONS This prospective study of reamer type indicates that RIA may be protective of systemic inflammation. This is supported by data showing decreased levels of IL-8 in the bronchial washings and increased level of IL-10 in the serum. Reaming and intramedullary fixation may cause an increase in IL-6 levels regardless of reamer type. Further investigations with a larger cohort of patients are desirable.

Middle-third clavicle fracture with associated type IV acromioclavicular separation: case report and literature review.

Review of available English literature suggests that combined injuries involving a clavicle shaft fracture and an acromioclavicular (AC) separation are rare. The force dissipation after the occurrence of either a midshaft clavicle fracture or an AC separation typically renders the injuries mutually exclusive. This article presents a review of literature on this combined injury pattern. A variety of treatment approaches have been put forth, including nonoperative, operative, and hybrid management of the two distinct injuries. The most appropriate treatment rendered depends on the degree of AC joint instability. This case report involves a midshaft clavicle fracture associated with a type IV AC separation in a patient ejected during a high-speed motor vehicle collision. Internal fixation of each injury was chosen and the patient had a successful final result. Other reported treatment options and recommendations are reviewed.

Compartment syndrome after low-energy tibia fractures sustained during athletic competition.

Objective: The purpose of this study was to determine whether patients who sustain tibia fractures during athletic competition are at an increased risk of developing acute compartment syndrome (ACS). Design: Retrospective review. Setting: University Level I trauma center. Participants/Patients: Acute tibia fractures in 626 patients between July 2006 and June 2009. Methods: A retrospective review of 626 consecutive tibia fractures treated by our department between July 2006 and June 2009 was performed. We recorded the mechanism and type of fracture as well as whether or not ACS developed. Soccer and football injuries were analyzed as specific groups. Chi square was used to analyze our results. Main Outcome Measurements: The rate of ACS in patients injured during sporting events versus that of all patients with a tibia fracture. Results: Thirty-four patients (5.4%) developed ACS, which is consistent with the published literature. Nine patients sustained the injury while playing soccer (1.4% of patients), whereas 11 patients (1.7%) were injured playing football. Five of the nine soccer players (55%; P < 0.001) and three of the football players (27%; P < 0.001) developed ACS. Collectively, tibia fractures sustained in football and soccer led to 25% of ACS cases despite accounting for only 3.1% of all tibia fractures. Conclusions: Tibia fractures sustained during soccer and football had a statistically significant association with development of ACS in our patient population during this time period. Such patients should be monitored closely and followed with high clinical suspicion for ACS.

The impact of race on the development of severe heterotopic ossification following acetabular fracture surgery

OBJECTIVES To determine the association between race on severe heterotopic ossification (HO) following acetabular fracture surgery. DESIGN Retrospective case control study. SETTING Level I university trauma centre. METHODS Two hundred and fifty-three patients who were surgically treated for acetabular fractures were retrospectively evaluated. Postoperative radiographs were evaluated for HO by a blinded musculoskeletal radiologist, and classified based on a modified Brooker classification. RESULTS Of the 253 patients that met inclusion and exclusion criteria, 175 (69%) were male and 78 (31%) were female. One hundred and fifty-four (61%) patients were Caucasian, and 99 (39%) were African American (AA). Fifty-five (21%) patients developed severe HO. Of those who developed severe HO, 25 were Caucasian (45%), 30 were African American (55%). Forty-one patients (75%) with severe HO were male, and 14 (25%) were female. No statistical differences (p>0.05) were found between groups in terms of age, days to surgery, GCS at presentation, surgical approach, perioperative HO prophylaxis, or AO/OTA fracture classification. The patient population was then stratified by race, gender, and race/gender. AA were more likely than Caucasians to develop severe HO (odds ratio [OR], 2.24; confidence interval [CI], 1.22-4.11). When gender was considered independent of race, no statistical differences (p>0.05) were observed (OR, 1.40; CI, 0.71-2.75). AA males were much more likely to develop severe HO when compared to Caucasian females (OR, 4.4; CI, 1.38-14.06). CONCLUSION Race is associated with different rates of severe HO formation following acetabular fracture surgery. AA patients are significantly more likely to develop severe HO following acetabular fracture surgery when compared to Caucasian patients.

Heterotopic Ossification in Trauma

Better understanding of the biology of heterotopic ossification (HO) formation will lead to treatment and prevention modalities that can be directed specifically at the cellular level. Early identification of HO precursor cells and target genes may provide prognostic value that guides individualized prophylactic treatment. Better understanding of molecular signaling and proteomics variability will allow surgeons to individualize preemptive treatment to suppress inflammation and formation of HO. Careful surgical technique to avoid muscle damage is important. Damaged muscle should be debrided as a prophylactic measure. Hemostasis and avoidance of a postoperative hematoma may decrease the chance of formation of HO.