Induced hypothyroidism alters articular cartilage in skeletally immature miniature swine.

PURPOSE/AIM: Thyroid hormone has been implicated in the normal growth and development of articular cartilage; however, its effect on a disease state, such as hypothyroidism, is unknown. The purpose of this investigation was to compare normal articular cartilage from proximal femurs of immature miniature swine to proximal femurs from hypothyroid-induced immature miniature swine. MATERIALS AND METHODS: Two 11-week-old male Sinclair miniature swine were made hypothyroid by administration of 6-propyl-2-thiouracil (PTU) in their drinking water; two control animals did not receive PTU. At 25 weeks of age, the animals were euthanized and their proximal femurs were fixed and decalcified. Samples were sectioned and analyzed by histology to define extracellular matrix (ECM) structure, immunohistochemistry (IHC) to identify types II and X collagen, and histomorphometry to assess articular cartilage mean total and localized height and cell density. Statistics included nested mixed-effects ANOVA with p ≤ 0.05 considered statistically significant. RESULTS: Compared to controls, hypothyroid articular cartilage demonstrated statistically significant quantitative differences in mean tissue height, mean cell density and type II collagen localized zone height. Qualitative differences in ECM proteoglycans and overall collagen types were also found. Type X collagen was not detected in either hypothyroid or control articular cartilage specimens. CONCLUSIONS: Significant changes in articular cartilage structure in hypothyroid compared to control immature miniature swine suggest that thyroid hormone is critical in the growth and development of articular cartilage. CLINICAL SIGNIFICANCE: Understanding articular cartilage development in immature animal models may provide insight into healing or repair of degenerative human articular cartilage.

A prospective comparison of computer-navigated and fluoroscopic-guided in situ fixation of slipped capital femoral epiphysis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is usually treated with percutaneous in situ screw fixation to prevent further progression of deformity. The purpose of this investigation is to compare computer navigation (CN) techniques with traditional fluoroscopic (fluoro) techniques for in situ fixation of SCFE. METHODS: This study was an IRB-approved prospective study of 39 hip pinnings in 33 children. CN techniques were used in 22 cases and fluoro in 17. The CN and fluoro groups were statistically similar in terms of grade and acuity of the slip. Children were assigned to the groups based on the intraoperative imaging technique used by the attending on call, with 3 surgeons in each group taking equal amounts of call. The "approach-withdraw" technique was used in all cases. Postoperative limited-cut, reduced-dose computed tomography (CT) scans were obtained to evaluate screw placement. This included blinded analysis for screw penetration of the joint, screw tip-to-apex distance, the distance the screw passed to the center of the physis, and attainment of center-center position. The number of pin passes, intraoperative radiation exposure, and operating room (OR) time were also analyzed. Statistics used included ANOVA, the χ and median tests. RESULTS: Compared with the fluoro group, CN resulted in more accurate screw placement. There was 1 case of joint penetration in the fluoro group not appreciated intraoperatively but detected on postoperative CT. CN also resulted in statistically significant (P < 0.05) reduced screw tip-to-apex distance and distance to the center of the physis. There was no statistically significant difference between the 2 groups in attainment of the center-center position, number of pin passes, or intraoperative radiation exposure. OR time averaged 19 minutes longer in the CN group. There was no case of avascular necrosis or chondrolysis in either of the groups. CONCLUSIONS: Compared with traditional fluoro techniques, CN in situ fixation of SCFE results in more accurate screw placement, comparable number of pin passes and intraoperative radiation exposure, and increased OR time. The cost-benefit ratio of this technology requires careful consideration at each individual institution. LEVEL OF EVIDENCE: II.

Clinically suspected scaphoid fractures in children.

PURPOSE: Scaphoid fractures are often missed in children because of their rarity and difficulty with radiographic diagnosis. Children are often treated for clinically suspected scaphoid fractures although there is no radiographic evidence for fracture on initial evaluation. The 2-fold purpose of this study is (1) to determine how many clinically suspected pediatric scaphoid fractures later became radiographically evident fractures and (2) to identify physical examination findings that suggest a scaphoid fracture when present at initial evaluation. METHODS: We performed separate retrospective and longitudinal reviews of children younger than 16 years referred to orthopaedics with traumatic wrist pain from January 1995 to April 2002. A total of 104 cases with high clinical suspicion but no radiographic evidence of scaphoid fracture on initial examination were included. Patients were followed until discharge to determine if they later demonstrated a confirmed fracture. In the longitudinal arm, 7 specific examination findings were recorded. Simple and multiple logistic regressions were used to analyze the data. RESULTS: Thirty-one (30%) of the 104 wrists with no initial radiographic evidence of fracture had a radiographically evident scaphoid fracture at follow-up. In the longitudinal arm (n = 41), the following 3 findings were statistically significant predictors of scaphoid fracture: volar tenderness over the scaphoid (P = 0.010), pain with radial deviation (P = 0.001), and pain with active wrist range of motion (P = 0.015). Presence of any of these findings was associated with a higher likelihood of scaphoid fracture. CONCLUSION: A high percentage (30%) of clinically suspected scaphoid fractures in children became radiographically evident fractures at follow-up. Volar scaphoid tenderness, radial deviation pain, and pain with active wrist range of motion can be used as signs to increase suspicion for eventual fracture. We recommend that all clinically suspected pediatric scaphoid fractures be immobilized with repeat radiographs and a clinical examination at 2 weeks. LEVEL OF EVIDENCE: II.

Orthopaedic Resident Use of an Electronic Medical Record Template Does Not Improve Documentation for Pediatric Supracondylar Humerus Fractures.

INTRODUCTION: Pediatric supracondylar humerus fractures are associated with a high incidence of nerve injury. Therefore, it is imperative that documentation be complete and accurate. This investigation compares orthopaedic resident history and physical (H&P) documentation of pediatric supracondylar fractures for completeness and accuracy with and without the use of an electronic medical record template. METHODS: The electronic medical record H&P documentation of 119 supracondylar humerus fractures surgically treated at a single pediatric institution was retrospectively reviewed. Templated and nontemplated groups were compared for documentation completeness and accuracy. Definitive diagnosis of a nerve palsy was made by a supervising orthopaedic attending surgeon. RESULTS: Forty-two cases had a templated H&P and 77 did not. The H&P documentation in the templated group was markedly more complete than that in the nontemplated group. However, the accuracy of the H&P documentation to identify nerve palsy was not statistically different between the two groups. Overall, the voluntary use of the orthopaedic template declined over time. CONCLUSION: Resident use of an orthopaedic template for documenting the H&P of pediatric supracondylar humerus fractures compared with nontemplated notes resulted in more complete documentation but only comparable accuracy. LEVEL OF EVIDENCE: III.

An investigation to validate the equivalence of physes obtained from different anatomic regions in a single animal species: Implications for choosing experimental controls in clinical studies.

Control tissue in studies of various orthopedic pathologies is difficult to obtain and presumably equivalent biopsies from other anatomic sites have been utilized in its place. However, for growth plates, different anatomic regions are subject to dissimilar mechanical forces and produce disproportionate longitudinal growth. The purpose of this study was to compare gene expression and structure in normal physes from different anatomic regions within a single animal species to determine whether such physes were equivalent. Thirteen female New Zealand white rabbits (five 15-week-old and eight 19-week-old animals) were euthanized and physes harvested from their proximal and distal femurs and proximal tibiae. Harvested physes were divided into groups for histological, immunohistochemical (IHC), and reverse transcription-quantitative polymerase chain reaction analyses. All physes analyzed demonstrated no apparent differences in morphology or proteoglycan staining intensity on histological examination or in type II collagen presence determined by IHC study. Histomorphometric measures of physeal height as well as gene expression of type II collagen and aggrecan were found to be statistically significantly equivalent (p < 0.05) among the three different bones from the total number of rabbits. Summary data suggest that the structural similarities and statistical equivalence determined among the various physes investigated in the rabbit validate these tissues in this species for use as surrogate controls by which physeal abnormalities may be compared and characterized in the absence of otherwise normal control tissues. Other species may exhibit the same similarities and equivalence among different physes so that such tissues may serve in like manner as controls for assessing a variety of orthopedic conditions, including those occurring in humans.

Interprofessional education model for geriatric falls risk assessment and prevention.

BACKGROUND: One in three people over the age of 65 fall every year, with 1/3 sustaining at least moderate injury. Falls risk reduction requires an interprofessional health team approach. The literature is lacking in effective models to teach students how to work collaboratively in interprofessional teams for geriatric falls prevention. The purpose of this paper is to describe the development, administration and outcome measures of an education programme to teach principles of interprofessional care for older adults in the context of falls prevention. METHODS: Students from three academic institutions representing 12 health disciplines took part in the education programme over 18 months (n=237). A mixed method one-group pretest and post-test experimental design was implemented to measure the impact of a multistep education model on progression in interprofessional collaboration competencies and satisfaction. RESULTS: Paired t-tests of pre-education to posteducation measures of Interprofessional Socialization and Valuing Scale scores (n=136) demonstrated statistically significant increase in subscales and total scores (p<0.001). Qualitative satisfaction results were strongly positive. DISCUSSION: Results of this study indicate that active interprofessional education can result in positive student attitude regarding interprofessional team-based care, and satisfaction with learning. Lessons learnt in a rapid cycle plan-do-study-act approach are shared to guide replication efforts for other educators. CONCLUSION: Effective models to teach falls prevention interventions and interprofessional practice are not yet established. This education model is easily replicable and can be used to teach interprofessional teamwork competency skills in falls and other geriatric syndromes.

Partial or non-union after triple arthrodesis in children: does it really matter?

PURPOSE: Triple arthrodesis is a commonly performed salvage procedure to correct hindfoot deformity. Non-union is considered an undesirable radiographic outcome; however, the clinical ramifications of this are not as well defined. The purpose of this study was to determine the incidence of partial or complete radiographic non-union after triple arthrodesis in children and characterize the clinical consequences. METHODS: An IRB-approved retrospective review of triple arthrodesis surgeries in patients less than 16 years of age performed by a single surgeon (DSW) identified 159 cases meeting the inclusion criteria. Plain radiographs were reviewed for bony fusion (defined as over 80 % radiographic bony union of the subtalar, calcaneocuboid, and talonavicular bones) and charts for clinical outcomes (pain, return to activity, and subsequent hindfoot surgeries). Statistics were used to compare the fused and unfused cases, with p < 0.05 considered to be significant. RESULTS: Of the 159 cases included in the study, 9 % did not achieve at least 80 % plain film radiographic union. The fused and unfused groups had similar clinical outcomes. Only one patient required surgery for sequelae of symptoms arising from a pseudoarthrosis related to the triple arthrodesis. The fused and unfused groups were similar in terms of gender and pin removal time, but differed significantly in surgical age and underlying diagnosis. CONCLUSIONS: This is one of the largest case series of pediatric triple arthrodesis surgery presented in the literature. This study demonstrated that good clinical outcomes can be achieved despite the lack of radiographic union after triple arthrodesis surgery in children. LEVEL OF EVIDENCE: IV.

A comparison of gastric and rectal CO2 in cardiac surgery patients.

Critical care nurses assess and treat clinical conditions associated with inadequate oxygenation. Changes in regional organ (gut) blood flow are believed to occur in response to a decrease in oxygenation. Although the stomach is a widely accepted monitoring site, there are multiple methodological and measurement issues associated with the gastric environment that limit the accuracy of P CO2 detection. The rectum may provide nurses with an alternative site for monitoring changes in P CO2 without the limitations associated with gastric monitoring. This pilot study used a repeated measures design to examine changes in gastric and rectal P CO2 during elective coronary artery bypass grafting with cardiopulmonary bypass (CPB) and in the immediate 4-hr postoperative period in 26 subjects. The systemic indicators explained little variation in the regional indicators during protocol. A comparison of rectal and gastric P CO2 revealed no statistically significant differences in the direction or magnitude of change over any phase of cardiac surgery (baseline, CPB, post-CPB). A reduction in both rectal and gastric P CO2 occurred during CPB, and both values trended upward during the post-CPB phase. However, poor correlation and agreement was found between the measures of P CO2 at the two sites. Although clinically important, the cause is unclear. Possible explanations include variation in CO2 production between the gastric and rectal site, differences in sensitivity of the two monitoring instruments, or the absence of hemodynamic complications, which limited the extent of change in P CO2. Further investigation using patients with more profound changes in oxygenation are needed to identify response patterns and possible mechanisms.

A study in vivo of the effects of a static compressive load on the proximal tibial physis in rabbits.

BACKGROUND: The effect of compression on the physis is generally defined by the Hueter-Volkmann principle, in which decreased linear growth of the physis results from increased compression. This investigation examined whether mechanically induced compression of rabbit physes causes changes in gene expression, cells, and extracellular components that promote physeal resilience and strength (type-II collagen and aggrecan) and cartilage hypertrophy (type-X collagen and matrix metalloprotease-13). METHODS: Static compressive loads (10 N or 30 N) were applied for two or six weeks across one hind limb proximal tibial physis of thirteen-week-old female New Zealand White rabbits (n = 18). The contralateral hind limb in all rabbits underwent sham surgery with no load to serve as an internal control. Harvested physes were divided into portions for histological, immunohistochemical, and quantitative reverse transcription-polymerase chain reaction analysis. Gene expression was statistically analyzed by means of comparisons between loaded samples and unloaded shams with use of analysis of variance and a Tukey post hoc test. RESULTS: Compared with unloaded shams, physes loaded at 10 N or 30 N for two weeks and at 10 N for six weeks showed histological changes in cells and matrices. Physes loaded at 30 N for six weeks were decreased in thickness and had structurally disorganized chondrocyte columns, a decreased extracellular matrix, and less intense type-II and X collagen immunohistochemical staining. Quantitative reverse transcription-polymerase chain reaction analysis of loaded samples compared with unloaded shams yielded a significantly (p ≤ 0.05) decreased gene expression of aggrecan and type-II and X collagen and no significant (p > 0.05) changes in the matrix metalloprotease-13 gene expression with increasing load. CONCLUSIONS: Compressed rabbit physes generate biochemical changes in collagens, proteoglycan, and cellular and tissue matrix architecture. Changes potentially weaken overall physeal strength, consistent with the Hueter-Volkmann principle, and lend understanding of the causes of pathological conditions of the physis.

Fracture incidence following plate removal in Legg-Calvé-Perthes disease: a 32-year study.

PURPOSE: The decision of whether or not to remove pediatric metallic implants remains a controversial issue. Many factors have been cited both in favor and against routine removal of metallic implants. The purpose of this study was to determine the fracture rate following the routine removal of hardware from patients with Legg-Calvé-Perthes (LCP) disease treated by proximal femoral varus osteotomy (PFVO) and to determine if there is an optimal time to remove hardware in this population. METHODS: We performed a retrospective chart review of children who had PFVO with subsequent hardware removal from March 1973 to May 2005 performed by a single surgeon. A total of 196 hips in 184 patients were included. Data was analyzed using logistic regression. Inverse prediction was also used to obtain estimates of the time needed to produce probabilities of no fracture. RESULTS: Ten out of the 196 hips included (5.1%) sustained a fracture after plate removal. The time from osteotomy to plate removal averaged 10.4 months in the nonfracture group and 4.8 months in the fracture group. This was statistically significant (P < 0.0001). Using the logistic regression model, the predicted time to plate removal corresponding to a 95% probability of no fracture was between 5.1 and 8.4 months. CONCLUSIONS: Plate removal remains a reasonable choice but questions remain as to the timing of removal. These data suggest that patients may benefit from extending the time to hardware removal beyond radiographic union to at least six months or more after the osteotomy.