Are Generative Pretrained Transformer 4 Responses to Developmental Dysplasia of the Hip Clinical Scenarios Universal? An International Review

OBJECTIVE

There is increasing interest in applying artificial intelligence chatbots like generative pretrained transformer 4 (GPT-4) in the medical field. This study aimed to explore the universality of GPT-4 responses to simulated clinical scenarios of developmental dysplasia of the hip (DDH) across diverse global settings.

METHODS

Seventeen international experts with more than 15 years of experience in pediatric orthopaedics were selected for the evaluation panel. Eight simulated DDH clinical scenarios were created, covering 4 key areas: (1) initial evaluation and diagnosis, (2) initial examination and treatment, (3) nursing care and follow-up, and (4) prognosis and rehabilitation planning. Each scenario was completed independently in a new GPT-4 session. Interrater reliability was assessed using Fleiss kappa, and the quality, relevance, and applicability of GPT-4 responses were analyzed using median scores and interquartile ranges. Following scoring, experts met in ZOOM sessions to generate Regional Consensus Assessment Scores, which were intended to represent a consistent regional assessment of the use of the GPT-4 in pediatric orthopaedic care.

RESULTS

GPT-4's responses to the 8 clinical DDH scenarios received performance scores ranging from 44.3% to 98.9% of the 88-point maximum. The Fleiss kappa statistic of 0.113 (P = 0.001) indicated low agreement among experts in their ratings. When assessing the responses' quality, relevance, and applicability, the median scores were 3, with interquartile ranges of 3 to 4, 3 to 4, and 2 to 3, respectively. Significant differences were noted in the prognosis and rehabilitation domain scores (P < 0.05 for all). Regional consensus scores were 75 for Africa, 74 for Asia, 73 for India, 80 for Europe, and 65 for North America, with the Kruskal-Wallis test highlighting significant disparities between these regions (P = 0.034).

CONCLUSIONS

This study demonstrates the promise of GPT-4 in pediatric orthopaedic care, particularly in supporting preliminary DDH assessments and guiding treatment strategies for specialist care. However, effective integration of GPT-4 into clinical practice will require adaptation to specific regional health care contexts, highlighting the importance of a nuanced approach to health technology adaptation.

LEVEL OF EVIDENCE

Level IV.

AP Radiographic Assessment of the Pediatric Pelvis for Developmental Dysplasia of the Hip

Mastering the art of roentgenographic analysis of the pediatric AP pelvis is paramount in the evaluation of developmental dysplasia of the hip. Understanding the normal radiographic development and the age-dependent changes in normal values allows assessment for pathologic changes. The goal of improving the analysis of the AP pelvis is to increase early detection of disease, assess progress toward normal values, and precisely follow the effects of treatment to improve clinical outcomes.

The Axillary Nerve Danger Zone in Percutaneous Fixation in the Pediatric Shoulder: The "1-Mountain-3-Valleys" Principle

BACKGROUND

Adult literature cites an axillary nerve danger zone of 5 to 7 cm distal to the acromion tip for open or percutaneous shoulder surgery, but that may not be valid for younger patients. This study sought to quantify the course of the axillary nerve in adolescent patients with reference to easily identifiable intraoperative anatomic and radiographic parameters.

METHODS

A single-institution hospital database was reviewed for shoulder magnetic resonance images (MRIs) in patients 10 to 17 years old. One hundred and one MRIs from patients with a mean age of 15.6 ± 1.2 years (range, 10 to 17 years) were included. Axillary nerve branches were identified in the coronal plane as they passed lateral to the proximal humerus and were measured in relation to identifiable intraoperative surface and radiographic landmarks, including the acromion tip, apex of the humeral head, lateral physis, and central apex of the physis. The physeal apex height (i.e., 1 "mountain") was defined as the vertical distance between the most lateral point of the humeral physis (LPHP) and the central intraosseous apex of the physis.

RESULTS

Axillary nerve branches were found in all specimens, adjacent to the lateral cortex of the proximal humerus. A mean of 3.7 branches (range, 2 to 6) were found. The mean distance from the most proximal branch (BR1) to the most distal branch (BR2) was 11.7 mm. The pediatric danger zone for the axillary nerve branches ranged from 6.6 mm proximal to 33.1 mm distal to the LPHP. The danger zone in relation to percent of physeal apex height included from 62% proximal to 242% distal to the LPHP.

CONCLUSIONS

All branches were found distal to the apex of the physis (1 "mountain" height proximal to the LPHP). Distal to the LPHP, no branches were found beyond a distance of 3 times the physeal apex height (3 "valleys"). In children and adolescents, percutaneous fixation of the proximal humerus should be performed with cortical penetration outside of this range. These parameters serve as readily identifiable intraoperative radiographic landmarks to minimize iatrogenic nerve injury.

CLINICAL RELEVANCE

This study provides valuable landmarks for percutaneous approaches to the proximal humerus. The surgical approach for the placement of percutaneous implants should be adjusted accordingly (i.e., performed at least 1 mountain proximal or 3 valleys distal to the LPHP) in order to prevent iatrogenic injury to the axillary nerve.

What is New in Pediatric Orthopaedic Foot and Ankle

BACKGROUND

This paper aims to report on the last 5 years of relevant research on pediatric foot and ankle pathology with specific focus on clubfoot, congenital vertical talus, toe walking, tarsal coalitions, pes planovalgus with or without accessory navicular, foot and ankle trauma, and talar dome osteochondritis dessicans.

METHODS

The Browzine platform was used to review the table of contents for all papers published in the following target journals related to the treatment of pediatric foot and ankle conditions. Search results were further refined to include clinical trials and randomized controlled trials published from March 1, 2015 to November 15, 2021.

RESULTS

A total of 73 papers were selected for review based on new findings and significant contributions in treatment of clubfoot, congenital vertical talus, toe walking, tarsal coalitions, pes planovalgus with or without accessory navicular, foot and ankle trauma, and talar dome osteochondritis dessicans. Also included were several papers that did not fit into any of these categories but provided new insight into specific foot and ankle pathologies.

CONCLUSIONS

Treatment strategies for children with foot and ankle pathology are continually evolving. We review many of the most recent publications with the goal of improving understanding of these pathologies and highlighting current best practices.

LEVEL OF EVIDENCE

Level III.

Idiopathic Toe-Walking in Children and Adolescents: Diagnosis, Natural History, and Treatment Options

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Idiopathic toe-walking is a diagnosis of exclusion.

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The natural history of idiopathic toe-walking has not been studied in many children; we identified only 1 prospective study. Of children without equinus contractures who were toe-walking before the age of 5.5 years, 59% had spontaneous resolution of toe-walking by 5.5 years of age, and 79%, by the age of 10 years.

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Adverse consequences of toe-walking into adulthood have not been reported, but may exist, and further research is needed to define and clarify.

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If parents desire treatment to resolve their child's toe-walking, surgical lengthening of the Achilles tendon is the treatment with the highest chance of success and lowest relapse rate, and thus far, no complications have been reported in any surgical series.

Is Grit Associated with Burnout and Well-being in Orthopaedic Resident and Faculty Physicians? A Multi-institution Longitudinal Study Across Training Levels

BACKGROUND

Grit has been defined as "perseverance and passion for long-term goals" and is characterized by maintaining focus and motivation toward a challenging ambition despite setbacks. There are limited data on the impact of grit on burnout and psychologic well-being in orthopaedic surgery, as well as on which factors may be associated with these variables.

QUESTIONS/PURPOSES

(1) Is grit inversely correlated with burnout in orthopaedic resident and faculty physicians? (2) Is grit positively correlated with psychologic well-being in orthopaedic resident and faculty physicians? (3) Which demographic characteristics are associated with grit in orthopaedic resident and faculty physicians? (4) Which demographic characteristics are associated with burnout and psychologic well-being in orthopaedic resident and faculty physicians?

METHODS

This study was an institutional review board-approved interim analysis from the first year of a 5-year longitudinal study of grit, burnout, and psychologic well-being in order to assess baseline relationships between these variables before analyzing how they may change over time. Orthopaedic residents, fellows, and faculty from 14 academic medical centers were enrolled, and 30% (335 of 1129) responded. We analyzed for the potential of response bias and found no important differences between sites in low versus high response rates, nor between early and late responders. Participants completed an email-based survey consisting of the Duckworth Short Grit Scale, Maslach Burnout Inventory-Human Services (Medical Personnel) Survey, and Dupuy Psychological Well-being Index. The Short Grit Scale has been validated with regard to internal consistency, consensual and predictive validity, and test-retest stability. The Psychological Well-being Index has similarly been validated with regard to reliability, test-retest stability, and internal consistency, and the Maslach Burnout Inventory has been validated with regard to internal consistency, reliability, test-retest stability, and convergent validity. The survey also obtained basic demographic information such as survey participants' age, gender, race, ethnicity, marital status, current year of training or year in practice (as applicable), and region of practice. The studied population consisted of 166 faculty, 150 residents, and 19 fellows. Beyond the expected age differences between sub-populations, the fellow population had a higher proportion of women than the faculty and resident populations did. Pearson correlations and standardized β coefficients were used to assess the relationships of grit, burnout, psychologic well-being, and continuous participant characteristics.

RESULTS

We found moderate, negative relationships between grit and emotional exhaustion (r = -0.30; 95% CI -0.38 to -0.21; p < 0.001), depersonalization (r = -0.34; 95% CI -0.44 to -0.23; p < 0.001), and the overall burnout score (r = -0.39; 95% CI -0.48 to -0.31; p < 0.001). The results also showed a positive correlation between grit and personal accomplishment (r = 0.39; 95% CI 0.29 to 0.48; p < 0.001). We also found a moderate, positive relationship between grit and psychologic well-being (r = 0.39; 95% CI 0.30 to 0.49; p < 0.001). Orthopaedic surgeons with 21 years or more of practice had higher grit scores than physicians with 10 to 20 years of practice. Orthopaedic surgeons in practice for 21 years or more also had lower burnout scores than those in practice for 10 to 20 years. Married physicians had higher psychologic well-being than unmarried physicians did.

CONCLUSION

Among orthopaedic residents, fellows, and faculty, grit is inversely related to burnout, with lower scores for emotional exhaustion and depersonalization and higher scores for personal accomplishment as grit increases.

CLINICAL RELEVANCE

The results suggest that grit could be targeted as an intervention for reducing burnout and promoting psychologic well-being among orthopaedic surgeons. Other research has suggested that grit is influenced by internal characteristics, life experiences, and the external environment, suggesting that there is potential to increase one's grit. Residency programs and faculty development initiatives might consider measuring grit to assess for the risk of burnout, as well as offering curricula or training to promote this psychologic characteristic.

Tendon Turndown to Bridge a Tibialis Anterior Gap and Restore Active Dorsiflexion After Degloving Foot Injury in a Child: A Case Report

CASE

A child with a severe degloving injury to the dorsum of the foot and ankle had segmental loss of the tibialis anterior tendon and toe extensors. A tendon turndown procedure was used, and the repaired tendon was covered with a latissimus muscle free flap to restore active ankle dorsiflexion. Details of the procedure are described, and active dorsiflexion and functional ambulation were restored.

CONCLUSIONS

The tendon turndown method is a simple and effective way to overcome segmental tendon loss of tibialis anterior and allowed restoration of active dorsiflexion in this case without relying on tendon transfers or grafting.

Does the location of short-arm cast univalve effect pressure of the three-point mould?

PURPOSE

Forearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however, the risk for re-displacement is high (7% to 39%). Proper cast application and the three-point moulding technique are modifiable factors that improve the ability of a cast to maintain the fracture reduction. Many providers univalve the cast to accommodate swelling. This study describes how the location of the univalve cut impacts the pressure at three-point mould sites for a typical dorsally displaced distal radius fracture.

METHODS

We placed nine force-sensing resistors on an arm model to collect pressure data at the three-point mould sites. Sensory inputs were sampled at 15 Hz. Cast padding and a three-point moulded short arm fibreglass cast was applied. The cast was then univalved on the dorsal, volar, radial or ulnar aspect. Pressure recordings were obtained throughout the procedure.

RESULTS

A total of 24 casts were analyzed. Casts univalved in the sagittal plane (dorsal or volar surface) retained up to 16% more pressure across the three moulding sites compared with casts univalved in the coronal plane (radial or ulnar border).

CONCLUSION

Maintaining pressure at the three-point mould prevents loss of reduction at the fracture site. This study shows that univalving the cast dorsally or volarly results in less pressure loss at moulding sites. This should improve the chances of maintaining fracture reductions when compared with radial or ulnar cuts in the cast. Sagittal plane univalving of forearm casts is recommended.

Quality Improvement and Patient Safety: How Leadership Can Create a Culture of Safety: AOA Critical Issues Symposium

Orthopaedic leaders need to create a shared vision and must establish trust, open lines of communication, and buy-in from all team members in order to establish a culture that is supportive of quality improvement. Leaders should encourage teams to follow evidence-based guidelines, reduce variation, take an active role in supply chain processes, and develop new ideas to improve quality and safety of care. With rapidly changing medical and surgical advancements, orthopaedic leaders must continually adapt in the face of evolving challenges.

EMTALA (Emergency Medical Treatment and Active Labor Act) Obligations: A Case Report and Review of the Literature

BACKGROUND

The Emergency Medical Treatment and Active Labor Act (EMTALA) was enacted in 1986 in the United States to address "patient dumping," or refusing to provide emergency care to patients and instead transferring them to other hospitals. Under EMTALA, the "reverse-dumping" provision prevents hospitals from refusing patients who require specialized capabilities or facilities if the hospital has the capacity to treat them. Despite this provision, patients continue to be transferred to distant tertiary care centers.

METHODS

We reviewed the literature on EMTALA in the context of a critically ill woman with an infection associated with an orthopaedic implant who was rejected from 2 geographically closer tertiary care centers and was ultimately transferred by helicopter ambulance to an academic teaching hospital that was 169 miles away from her home.

RESULTS

After transfer to our tertiary care, level-I trauma center, the patient spent 61 days in the intensive care unit; she required 9 operative procedures, which totaled 1,520 minutes of operative time. Eighteen medical specialties and 8 ancillary medical consulting teams were involved in her care. She underwent 1,436 laboratory and 83 radiographic studies. The total reimbursement from Medi-Cal (California's Medicaid program) for her care in our tertiary care center was $463,753; the hospital charges were more than tenfold higher.

CONCLUSIONS

Dumping and reverse dumping continue despite compromise of patient care and the high financial burden of the accepting institutions. This may be due to ineffective monitoring and enforcement, lack of uniformity among the courts, and lack of incentive to receive uninsured or poorly funded patients. Under EMTALA, it is difficult for tertiary care centers to argue lack of specialized capabilities or capacity to accept patients, and neither hospitals nor physicians are compensated for the charges of providing care to uninsured or underinsured patients. Moving forward, efforts to better align financial incentives through cost-sharing between community hospitals and tertiary care centers, increased clinician literacy regarding the provisions of EMTALA, and increased transparency with hospital transfers may help improve EMTALA compliance and patient care.

Orthopaedic phenotyping of NGLY1 deficiency using an international, family-led disease registry

BACKGROUND

NGLY1 deficiency is a rare autosomal recessive disorder caused by loss in enzymatic function of NGLY1, a peptide N-glycanase that has been shown to play a role in endoplasmic reticulum associated degradation (ERAD). ERAD dysfunction has been implicated in other well-described proteinopathies, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. The classical clinical tetrad includes developmental delay, hypolacrima, transiently elevated transaminases, and hyperkinetic movement disorders. The musculoskeletal system is also commonly affected, but the orthopaedic phenotype has been incompletely characterized. Best practices for orthopaedic clinical care have not been elucidated and considerable variability has resulted from this lack of evidence base. Our study surveyed patients enrolled in an international registry for NGLY1 deficiency in order to characterize the orthopaedic manifestations, sequelae, and management.

RESULTS

Our findings, encompassing the largest cohort for NGLY1 deficiency to date, detail levels of motor milestone achievement; physical exam findings; fracture rates/distribution; frequency of motor skill regression; non-pharmacologic and non-procedural interventions; pharmacologic therapies; and procedural interventions experienced by 29 participants. Regarding the orthopaedic phenotype, at time of survey response, we found that over 40% of patients experienced motor skill regression from their peak. Over 80% of patients had at least one orthopaedic diagnosis, and nearly two-thirds of the total had two or more. More than half of patients older than 6 years had sustained a fracture. Related to orthopaedic non-medical management, we found that 93 and 79% of patients had utilized physical therapy and non-operative orthoses, respectively. In turn, the vast majority took at least one medication (including for bone health and antispasmodic therapy). Finally, nearly half of patients had undergone an invasive procedure. Of those older than 6 years, two-thirds had one or more procedures. Stratification of these analyses by sex revealed distinctive differences in disease natural history and clinical management course.

CONCLUSIONS

These findings describing the orthopaedic natural history and standard of care in patients with NGLY1 deficiency can facilitate diagnosis, inform prognosis, and guide treatment recommendations in an evidence-based manner. Furthermore, the methodology is notable for its partnership with a disease-specific advocacy organization and may be generalizable to other rare disease populations. This study fills a void in the existing literature for this population and this methodology offers a precedent upon which future studies for rare diseases can build.

The Educational Opportunities Provided by a Pediatric Orthopedic Urgent Case Review Conference: Keep Score to Provide a Better Experience

OBJECTIVE

To evaluate the distribution of conditions presented at a case conference to assess resident educational exposure to acute pediatric orthopedic conditions.

DESIGN

Retrospective review of emergency department and inpatient consultations presented at a daily pediatric orthopedic case conference over a 3-year period. Consultations were divided into 3-month resident rotation blocks for analysis.

SETTING

Tertiary children's hospital in the southern United States which host residents from 2 orthopedic surgery residency programs.

PARTICIPANTS

The case conference is attended by pediatric orthopedic surgeons, 1 pediatric orthopedic fellow, and 4 PGY III/IV residents.

RESULTS

A total of 1762 consultations were presented at the conference. The consultations were obtained for traumatic injuries, 86.5% (1524/1762); infections, 7.7% (136/1762); and congenital/other problems, 5.8% (102/1762). The 3 most common consultations per rotation were fractures: both-bone forearm (mean, 46.1; range: 24-64), supracondylar humerus (mean, 23.8; range: 17-31), and distal radius (mean, 13.8; range: 7-33). Less common consultations per rotation were septic arthritis (mean, 1.6; range: 0-5), child abuse (mean, 1.3; range: 0-5), Monteggia fracture (mean, 0.3; range: 0-1), compartment syndrome (mean, 0.2; range: 0-1) and patella sleeve fracture (mean, 0.1; range: 0-1).

CONCLUSIONS

There was a large disparity between conditions in the number of times presented and reviewed within a 3-month rotation at the daily case conference, with some important conditions not being discussed at all in each rotation. This finding documents a disadvantage of case conferences based on limiting discussion to current patients, and highlights an opportunity for educational improvement.

A survey of resident perspectives on surgical case minimums and the impact on milestones, graduation, credentialing, and preparation for practice: AOA critical issues

Residency education continues to evolve. Several major changes have occurred in the past several years, including emphasis on core competencies, duty-hour restrictions, and call. The Accreditation Council for Graduate Medical Education (ACGME) Next Accreditation System (NAS) implemented educational milestones in orthopaedic surgery in July 2013. Additionally, the Residency Review Committee for orthopaedic surgery published suggested surgical case minimums in 2012, which overlap with several of the milestones.We conducted a survey to assess the opinions of orthopaedic residents regarding the ACGME-suggested surgical case minimums and the effects that these may have on resident education and potential future privileges in hospitals. The survey was sent via e-mail to all of the residents participating in the American Orthopaedic Association (AOA) Resident Leadership Forum for both 2011 and 2012. Participants in the Resident Leadership Forum are in either postgraduate year 4 or postgraduate year 5, are selected by the program directors as resident leaders, and represent 80% of the orthopaedic residency programs in the United States. The survey was completed by 157 of the 314 participants. Sixty-nine percent of the participants believed that case logs with minimum numbers of surgical procedures were an effective way to monitor the work but were not necessarily the only way to monitor the educational progress of the residents. Thirty-two percent believed that the minimums should not be required. Overwhelmingly, there was agreement that important cases were missing from the currently proposed sixteen core surgical minimums. Specifically, the residents believed that a minimum number of cases are necessary for distal radial fracture fixation and proximal humeral fracture fixation and possibly have a milestone to reflect the progress of the residents for each fixation.Most residents thought that surgical case minimums are an effective tool in monitoring the progress of residents and measuring the effectiveness of residency programs. However, the surgical ability of an individual resident should not be evaluated on case minimums alone. The development of the milestones to assess competency should continue, but, as surgical skill is not a specific core competency, perhaps other methods for assessing surgical proficiency need to be developed rather than case minimums. Surgical skills laboratories and proctoring residents independently performing procedures may help to assess surgical proficiency, in addition to traditional faculty and 360° evaluations. Combining these types of assessments with surgical case logs documenting the residents' educational experience seems to be the best path going forward in assessing the development of young surgeons.

Assessing the Value of Work Done by an Orthopedic Resident During Call

BACKGROUND

Medicare funding for graduate medical education may be cut in the next federal budget.

OBJECTIVE

We quantified the value of work that 1 orthopedic surgery resident performs on call and compare it to Medicare educational funding received by the hospital for each resident.

METHODS

A single orthopedic resident's on-call emergency department and inpatient consults were collected during a 2-year call period at a large, tertiary, level-1 trauma center. Patient charts were reviewed; ICD-9 codes, evaluation and management, and procedural treatment were recorded. Codes were converted into work relative value units. The number of work relative value units was multiplied by the 2012 Medicare rate of $34.03 per relative value units to calculate the monetary value of resident work.

RESULTS

Of 120 resident call shifts, 115 call sheets (95.8%) were available for review, and 1160 patients were seen (average  =  10.09 consults/call). A total of 4688 work relative value units were generated (average  =  40.76 per night), and the total dollar value generated was $159,561 ($1,387 per call) during the 2 years of call (average  =  $79,780 annually). Evaluation and management codes generated 2340 work relative value units, with a calculated dollar amount of $79,648, and procedural codes generated 2348 work relative value units, with a calculated dollar amount of $79,913.

CONCLUSIONS

Our institution estimated Medicare direct medical education support per resident at $40,000/y, and total funding was $130,000/resident. At our tertiary care institution, the unbilled work of 1 orthopedic resident on call amounts to more than 60% of Medicare direct medical education and indirect medical education funding annually.

The perfused, pulseless supracondylar humeral fracture: intermediate-term follow-up of vascular status and function

BACKGROUND

This study provides intermediate-term follow-up data on the vascular status of a cohort of children with a perfused, pulseless supracondylar humeral fracture who were managed with closed reduction, percutaneous pinning, and observation.

METHODS

Pediatric patients who sustained a perfused, pulseless supracondylar humeral fracture in the period from 2007 to 2011 and who had at least six months of clinical follow-up were identified and returned for evaluation. The primary outcome was vascular status as indicated by palpation of the radial pulse, the wrist brachial index, and arterial patency on duplex ultrasound. Secondary outcomes included functional parameters assessed with the Pediatric Outcomes Data Collection Instrument (PODCI), arm circumference, arm length, elbow motion, neurologic findings, muscle endurance, grip strength, and intolerance to cold.

RESULTS

Follow-up data were obtained for twenty of thirty-six patients with a Gartland type-III fracture who had been managed with closed reduction and percutaneous pinning. Five patients had a return of a palpable pulse in the operating room after closed reduction and percutaneous pinning. All twenty had a palpable radial pulse at the time of the latest follow-up, and all nerve palsies resolved. Duplex ultrasound performed at the time of follow-up showed that fourteen patients had a patent brachial artery, five had brachial artery occlusion with large collateral vessels, and one had severe arterial stenosis. All fourteen patients with a patent brachial artery, two of the five with an occluded brachial artery, and the patient with a stenotic brachial artery had a normal wrist brachial index. Three patients with an occluded brachial artery had an abnormal wrist brachial index (0.73, 0.71, and 0.80). No differences between the injured and uninjured sides were observed with regard to arm circumference, arm length, elbow motion, muscle endurance, or grip strength. Thirteen of the twenty patients had higher functioning in all domains of the PODCI questionnaire compared with the general population. Two patients (one with an occluded artery and one with a patent artery) had lower values on the global functioning score.

CONCLUSIONS

After an average of twenty months of follow-up, children with a perfused, pulseless supracondylar humeral fracture that had been treated with closed reduction, percutaneous pinning, and observation demonstrated a palpable distal radial pulse, normal growth of the arm, and good/excellent functional outcomes, although five of the twenty patients had an occluded brachial artery.

LEVEL OF EVIDENCE

Therapeutic level IV. See Instructions for Authors for a complete description of levels of evidence.

Obesity in pediatric orthopaedics

Obesity is a rapidly expanding health problem in children and adolescents and is the most prevalent nutritional problem for children in the United States. Some believe that obesity has become a major epidemic in American children, with the prevalence having more than doubled since 1980. This epidemic has led to a near-doubling in hospitalizations with a diagnosis of obesity between 1999 and 2005 and an increase in costs from $125.9 million to $237.6 million between 2001 and 2005. This article describes some of the orthopaedic conditions commonly encountered in overweight/obese children and adolescents, classically infantile and adolescent tibia vara and slipped capital femoral epiphysis. Also discussed are genu valgum, which has been associated with obesity, and other difficulties encountered in providing orthopaedic care to obese children.

Sequelae of pediatric hip disorders: survey responses from experts in adult hip reconstruction

Questions persist concerning the incidence of total hip arthroplasties (THAs) attributable to secondary osteoarthrosis and the impact of corrective pediatric hip surgeries and retained internal fixation on subsequent THAs. Hip reconstruction fellowship directors (N = 72) were mailed a survey of multiple-choice questions about pediatric hip disorders (PHDs) in their THA populations, the influence of hip osteotomies on subsequent THAs, and the recommendation to routinely remove pediatric hip internal fixation. Forty-five surgeons (62.5%) responded. The majority reported that a small proportion of hip arthrosis in their practice was attributable to PHDs (10-30 cases per 100-200 annual cases). Fifty-seven percent indicated that hip surgery performed during skeletal immaturity made THA more difficult. Twenty-eight surgeons (62% of respondents) said that they remove implants from fewer than 10% of cases with previous pediatric surgery. Sixty-eight percent felt that removal of pediatric hip implants, particularly those in the proximal femur (83% of respondents), should be routine. Survey results showed that the majority of experts in adult hip reconstruction (a) do not identify PHDs as a significant factor in most of their patients with end-stage hip arthrosis and (b) believe in routine removal of pediatric hip implants, particularly those in the proximal femur. The impact of performing corrective hip surgery during skeletal immaturity--whether such surgery increases the difficulty of or diminishes the effectiveness of subsequent THA--remains controversial.

Results of the Ponseti method in patients with clubfoot associated with arthrogryposis

Clubfoot associated with arthrogryposis has been traditionally considered very resistant to manipulation and casting, and therefore has required surgical correction. The purpose of this study was to evaluate the results of the Ponseti method of clubfoot casting in this patient population. We reviewed the records of patients with clubfoot associated with arthrogryposis consecutively treated at our respective institutions from January 1992 to December 2004. All patients were treated by serial manipulations and casting following the principles of the Ponseti method. Main outcome measures included initial correction of the deformity, relapses and the need for surgical releases or any other surgeries. Average age at last follow up was 4.6 years. There were 16 patients, all with bilateral deformities (32 clubfeet). there were 11 males and 5 females. Nine patients had both upper and lower extremity involvement. Seven patients had previous treatment elsewhere and one patient had an Achilles tenotomy. Initial correction was obtained in all but 1 patient. Average number of casts required for correction was 7 (range: 5 to 12). Average post-tenotomy dorsiflexion was 5 degrees. One patient required a posterior-medial release (PMR) for insufficient initial correction. Four cases required subsequent surgery for relapses (1 bilateral PMR with a repeat left PMR; 2 posterior releases (PR), 1 PR and anterior tibialis transfer (ATT), and 1 ATT). No talectomies were required. This study demonstrates that the Ponseti method is very effective for the correction of patients with clubfoot associated to arthrogryposis. Although this deformity is more rigid than in idiopathic clubfoot, many cases can be corrected when started in the first few weeks after birth.

Advances in the surgical management of pediatric femoral shaft fractures

PURPOSE OF REVIEW

To provide an update on surgical methods of pediatric femur fracture treatment.

RECENT FINDINGS

Multiple studies describe successful results with elastic nail stabilization of pediatric femur fractures. The indications and risk factors for complications are being more clearly defined. Trochanteric entry-locked intramedullary nailing and submuscular bridge plating have also recently been reported to produce excellent outcomes in a high percentage of patients. Older (>11 years) patients, heavier patients and patients with length-unstable fracture patterns may be best treated with locked nailing or plating.

SUMMARY

Pediatric femur fractures can be successfully treated by a number of methods. This review examines the recent literature to provide some guidelines for choosing amongst the options for surgical stabilization.

Titanium elastic nailing of fractures of the femur in children

Between 1996 and 2003 six institutions in the United States and France contributed a consecutive series of 234 fractures of the femur in 229 children which were treated by titanium elastic nailing. Minor or major complications occurred in 80 fractures. Full information was available concerning 230 fractures, of which the outcome was excellent in 150 (65%), satisfactory in 57 (25%), and poor in 23 (10%). Poor outcomes were due to leg-length discrepancy in five fractures, unacceptable angulation in 17, and failure of fixation in one. There was a statistically significant relationship (p = 0.003) between age and outcome, and the odds ratio for poor outcome was 3.86 for children aged 11 years and older compared with those below this age. The difference between the weight of children with a poor outcome and those with an excellent or satisfactory outcome was statistically significant (54 kg vs 39 kg; p = 0.003). A poor outcome was five times more likely in children who weighed more than 49 kg.

Evaluation of the child who has hip pain

Evaluation of children who have hip pain can be a diagnostic challenge. This article reviews pertinent history taking, physical examination, laboratory testing, and imaging studies that assist in reaching a correct diagnosis. It also reviews the diagnostic categories that are important in formulating a differential diagnosis to frame clinical decision making.

Ponseti management of clubfoot in older infants

Treatment of clubfoot with the Ponseti method is successful when performed immediately after birth. We treated 23 infants (36 feet) who presented to us after casting, applied at other institutions, failed or after 3 months of age. Twenty-two infants had serial casting started during the first 2 months, and one infant who was 6 months old at presentation had not received previous treatment. The original orthopaedists of 18 patients advised posteromedial release. The parameter studied was the need for posteromedial release (ie, failure of Ponseti casting and percutaneous Achilles tenotomy to obtain satisfactory clinical appearance). Only one (2.8%) of 36 feet required open surgical release (posterior only). Thirty-five feet required percutaneous Achilles tenotomy. A mean of six Ponseti casts were applied before tenotomy. Two feet (two infants) required anterior tibialis transfer for mild relapse; three other feet (two infants) required repeat casting for mild relapse. Most pediatric orthopaedists think that successful clubfoot casting depends on treatment started immediately after birth. Our data suggest that older infants with clubfoot can be treated successfully without extensive surgery. Our results in older infants are similar to the results of a previous study we conducted with younger infants. In that study, one (2.9%) of 34 feet required posteromedial release surgery.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (Case series). See the Guidelines for Authors for a complete description of levels of evidence.

Gene expression during fracture healing in rats comparing intramedullary fixation to plate fixation by DNA microarray

OBJECTIVE

This study was designed to compare mRNA gene expression in healing diaphyseal femoral fractures between those injuries treated with intramedullary nails and those treated with internal plate fixation.

DESIGN

RNA gene expression was measured at 1 day, 3 days, and 1, 2, 4, and 6 weeks after surgery in the fracture callus of rats randomized to femoral shaft fracture with intramedullary nail fixation, rigid plate fixation, or sham fracture.

SETTING

AAALAC-accredited vivarium of an independent academic medical center.

ANIMALS

Fifty-seven, adult, female, Sprague-Dawley rats at 16 weeks of age.

INTERVENTION

Femoral fracture with intramedullary nail fixation, femoral fracture with plate and screw fixation, or sham surgery with no fracture.

MAIN OUTCOME MEASUREMENTS

RNA expression for 8700 genes was measured with 19 Affymetrix U34A microarrays. The fracture callus was significantly larger with intramedullary nail fixation than with plate fixation. Most genes responded to fracture with a change in mRNA expression. Most of the responding genes followed the same time course for both fixation methods. This included genes related to growth factors, bone matrix, mast cells, most nerve factors, and hematopoiesis. The intramedullary nail group had significantly greater up-regulation for transcripts related to cartilage, cell division, inflammation, and the acetylcholine receptor. There was significantly greater up-regulation in the plate group for genes related to macrophage activity.

CONCLUSIONS

There were differentially expressed genes present between the 2 surgical groups that may give insight into the control of fracture repair.

The Ponseti method of treatment for congenital clubfoot: importance of maximal forefoot supination in initial casting

The correction of cavus deformity requires further supination of the forefoot. In the Ponseti method, the initial cast is applied with the forefoot supinated such that the plane of the metatarsal heads is parallel to the long axis of the tibia. This study reviewed Pirani scores of 27 patients with 38 clubfeet treated over an 18-month period by the Ponseti method to evaluate changes in midfoot deformity after the initial cast. Initial average scores for severity of the lateral border deformity, medial crease, and talonavicular joint reducibility decreased from 0.92, 0.75, and 0.75, respectively, to 0.73, 0.25, and 0.5, respectively, after the first cast. The improvement in Pirani scores provides support for the efficacy of the initial cast to reduce the cavus and also increase the reducibility of the midfoot. Failure to address the cavus deformity with the initial cast as described by Ponseti may lead to persistent rigidity and incomplete correction.

Informed consent is not routinely documented for procedures using allografts

Patients who receive musculoskeletal allografts may have severe postoperative infections develop. Media reports have heightened public awareness of the risk of allograft use. Explaining these risks to patients preoperatively has become more important as attention to informed consent issues has increased. This study retrospectively investigated the patterns of informed consent for allograft bone used during elective orthopaedic procedures at a major teaching hospital. Forty-seven (32%) of 148 patients had preoperative discussions of allograft risks and benefits documented with a signed preoperative consent. In nearly 70% of the cases in which structural allograft was used, preoperative consent was documented. Only 8% of cases in which nonstructural, highly processed allograft was used had documented preoperative consent. Forty-eight (32%) of 148 patients were treated with allograft and autograft. Consent was obtained for the harvesting and use of autograft from 90% of these patients. In none of these patients was consent obtained for the allograft used. Although risks of disease transmission vary widely with the degree of allograft processing and the source of its procurement, informed consent for any allograft use should be a routine part of preoperative discussions of risks and benefits in elective orthopaedic surgeries.

Spinal osteochondroma presenting as atypical spinal curvature: a case report

STUDY DESIGN

The case of an 8-year-old girl with hereditary multiple exostosis presenting with atypical spinal curvature is reported.

OBJECTIVE

To describe a case of spinal curvature caused by an osteochondroma, illustrating the need for careful evaluation of patients with hereditary multiple exostosis presenting with "scoliosis."

SUMMARY OF BACKGROUND DATA

Osteochondromas have been known to arise in the spinal canal and to present with symptoms of neural compression. Spinal curvature is a rare presenting sign of osteochondromas.

METHODS

The patient's medical and radiographic history is reviewed as well as the medical literature.

RESULTS

An 8-year-old girl with hereditary multiple exostosis was referred for possible thoracotomy and anterior decompression of a T4 osteochondroma thought to be causing an atypical "scoliosis." Further examination, review of the radiographs, and computed tomography scan showed a large L4 osteochondroma encroaching on the neural elements. The patient's neurologic symptoms and spinal curvature resolved in the 2 years after surgical excision of the lumbar osteochondroma.

CONCLUSIONS

Patients with hereditary multiple exostosis and spinal curvature require further diagnostic evaluation to ensure that an osteochondroma in the spinal canal is not the cause of that curvature.

Femoral anteversion in children with cerebral palsy. Assessment with two and three-dimensional computed tomography scans

BACKGROUND

Assessment of femoral anteversion in children with cerebral palsy with two or three-dimensional computed tomography scans may be limited by both positional and anatomic variables. Three-dimensional computed tomography techniques are considered to be more accurate than two-dimensional imaging when the femur is not optimally positioned in the gantry or when the neck-shaft angle is increased.

METHODS

Computed tomography scanning was performed on a series of nine model femora with anteversion ranging from 20 degrees to 60 degrees and neck-shaft angles ranging from 120 degrees to 160 degrees. Each femoral model was scanned in two holding devices, the first of which held the femur in optimal alignment (normal model) and the second of which held the femur in flexion, adduction, and internal rotation (cerebral palsy model) relative to the gantry. Femoral anteversion was calculated for each model from two and three-dimensional computed tomography scans by four examiners on two separate occasions. The intraobserver and interobserver reliability, the accuracy, and the effect of increasing the neck-shaft angle on the accuracy of the measurements made on the two and three-dimensional scans of the normal and cerebral palsy models were then examined.

RESULTS

The mean differences in the measurements of femoral anteversion made by the same examiner (intraobserver reliability) were <2 degrees for the two-dimensional scans of the normal and cerebral palsy models and the three-dimensional scans of the normal models, and the mean difference was <4 degrees for the three-dimensional scans of the cerebral palsy models. The mean differences among examiners (interobserver reliability) were <3 degrees for the two-dimensional scans of the normal and cerebral palsy models and the three-dimensional scans of the normal models, and the mean difference was <6 degrees for the three-dimensional scans of the cerebral palsy models. The accuracy of the assessments of femoral anteversion of the normally aligned models was comparable between the two and three-dimensional scans. However, the three-dimensional assessment was significantly more accurate than the two-dimensional assessment for measurement of anteversion of the cerebral palsy models (p = 0.003). Accuracy within 5 degrees was comparable between the two and three-dimensional scans for measurement of the normally aligned models, with 86% of the two-dimensional measurements and 78% of the three-dimensional measurements falling within 5 degrees of the actual measurements. However, the accuracy within 5 degrees was significantly compromised when the models were placed in cerebral palsy alignment. Only 3% of the two-dimensional measurements and 14% of the three-dimensional measurements fell within 5 degrees of the actual measurements, with three-dimensional assessment being significantly better than two-dimensional assessment (p = 0.006). Increasing the neck-shaft angle did not significantly compromise the accuracy of measurement of femoral anteversion with either the two-dimensional or the three-dimensional technique (p > 0.05 for all comparisons).

CONCLUSIONS

When adequate alignment of the femur in the computed tomography scanner was possible, a simple two-dimensional technique exhibited excellent intraobserver and interobserver reliability and clinically acceptable accuracy within the relevant ranges of anatomic variability tested (neck-shaft angles of 120 degrees to 160 degrees and femoral anteversion of 20 degrees to 60 degrees). When optimal alignment of the femur in the scanner was not possible, neither two-dimensional nor three-dimensional techniques exhibited clinically acceptable accuracy for the measurement of femoral anteversion.

Surgical correction of residual hip dysplasia in two pediatric age-groups

BACKGROUND

The goal of operative treatment of hip dysplasia or subluxation in children is to normalize the hip joint to delay or prevent the premature onset of osteoarthritis. In theory, intervention in early childhood, when the remodeling potential is greater, should provide the best opportunity for the development of a normal joint.

METHODS

To determine the efficacy of early surgical intervention in restoring the normal morphology of the hip, according to radiographic criteria, we reviewed the cases of thirty-six children (fifty hips) with residual dysplasia or subluxation who were managed with either a femoral and/or a pelvic osteotomy when they were between two and eight years old (Group I). The average age at the time of surgery was 3.7 years, and the average duration of follow-up was 4.3 years. We compared these results with those achieved in fourteen patients (eighteen hips) with residual hip dysplasia or subluxation who were treated surgically at an older age, between eight and eighteen years old (Group II). The outcome was assessed with use of clinical as well as multiple radiographic criteria. We believe that a normal relationship between the acetabulum and the femoral head was established when there was an acetabular index of <20 degrees or a Sharp angle of <42 degrees, a center-edge angle of >20 degrees, and an intact Shenton's line.

RESULTS

At the time of the latest follow-up, sixteen of the seventeen hips with residual dysplasia that had been treated with pelvic osteotomy alone in Group I and three of four such hips in Group II had a normal relationship between the acetabulum and the femoral head. Normal radiographic findings were noted in fifteen of the seventeen hips with residual subluxation that had been treated with combined femoral and pelvic osteotomies in Group I compared with four of eight such hips in Group II.

CONCLUSIONS

We found that residual hip dysplasia or subluxation could be more predictably corrected, with normal radiographic results and with less morbidity and fewer complications, in children who were between two and eight years old than in those who were between eight and eighteen years old. Long-term follow-up is required to confirm whether the improved anatomy and function of the hip that resulted from early correction of residual dysplasia or subluxation lasts into adulthood.

Altered fibular growth patterns after tibiofibular synostosis in children

BACKGROUND

Iatrogenic synostosis of the tibia and fibula following an operation on the leg in a child has been reported rarely in the literature, and the effects of this complication on future growth, alignment, and function are not known. This is a retrospective case series, from one institution, of crossunions of the distal parts of the tibia and fibula complicating operations on the leg in children. The purpose is to alert surgeons to this possible complication.

METHODS

The senior author identified eight cases of iatrogenic tibiofibular synostosis seen in children since 1985. The patients had various diagnoses and were from the practices of four pediatric orthopaedic surgeons. Synostosis developed in six patients after osteotomies of the distal parts of the tibia and fibula, in one after internal fixation of distal tibial and fibular metaphyseal fractures through a single incision, and in one after posterior transfer of the anterior tibialis tendon through the interosseous membrane combined with peroneus brevis transfer to the calcaneus. Medical records were reviewed, and preoperative and follow-up radiographs were analyzed for changes in the relative positions of the proximal and distal tibial and fibular physes and in the alignment of the ankle.

RESULTS

Five patients were symptomatic after crossunion; they presented with prominence of the proximal part of the fibula, ankle deformity, or ankle pain. Three patients were asymptomatic, and a synostosis was identified on routine follow-up radiographs. Intraoperative technical errors caused two of the crossunions; the cause of the others was unknown. Following tibiofibular synostosis, growth disturbances were noted radiographically in every patient. The normal growth pattern of distal migration of the fibula relative to the tibia was reversed, resulting in a decreased distance between the proximal physes of the tibia and fibula as well as proximal migration of the distal fibular physis relative to the distal part of the tibia. Shortening of the lateral malleolus led to greater valgus alignment of the ankle.

CONCLUSIONS

Tibiofibular synostosis can complicate an operation on the leg in a child. After crossunion, the normal distal movement of the fibula relative to the tibia is disrupted, resulting in shortening of the lateral malleolus and ankle valgus as well as prominence of the fibular head at the knee. The synostosis also interferes with the normal motion that occurs between the tibia and fibula with weight-bearing, potentially leading to ankle pain.

Scoliosis in children with anterior chest wall deformities

An association between anterior chest wall deformities and scoliosis is described in the literature but is poorly defined. It appears that only approximately 4% to 5% of patients with severe anterior chest wall deformities have scoliosis of sufficient magnitude to warrant evaluation and observation by a spinal deformity physician. The relationship between anterior chest wall deformity and scoliosis is most clear in patients with Marfan syndrome. Marfan patients with scoliosis are at high risk for progression of deformity to unacceptable levels and have historically not responded well to brace therapy. The causes of anterior chest wall deformity and scoliosis remain unclear, although unbalanced cartilage growth has been proposed as a potential cause of both. Some have proposed that chest wall deformity may result in asymmetric spinal forces and subsequent scoliosis secondary to altered spinal growth. Because of the association between pectus deformities and scoliosis, patients with anterior chest wall deformities should be carefully examined for signs of scoliosis and have screening radiographs if indicated. Young patients in particular should be referred to a spinal deformity physician, because it is clear that patients who present with spinal deformity prior to age 5 years are the ones at risk for adverse cardiopulmonary sequelae related to spinal deformity. Most children with scoliosis and anterior chest wall deformities need only observation of the scoliosis. In more severe cases, the management of spinal deformity traditionally involves the use of bracing to attempt to control curves of lesser magnitude and surgical management for unacceptable deformities or curves of magnitudes too great for brace treatment. There are no studies that specifically address the use of these methods in patients with both anterior chest wall deformities and scoliosis. The management of scoliosis in patients with anterior chest wall deformities follows treatment principles outlined for idiopathic scoliosis patients.

Early surgical correction of residual hip dysplasia: the San Diego Children's Hospital approach

Studies of the etiology of premature osteoarthritis of the hip show that the most common cause is residual childhood hip dysplasia. Hip dysplasia is often asymptomatic in childhood, making detection difficult and creating complex treatment decisions (major surgery in the asymptomatic child). Symptoms do not develop typically until the teenage or early adult years, and surgical correction at this age is often incomplete and complicated. In contrast, if the dysplasia is recognized early, surgical correction can be performed using simpler osteotomies with more predictable results. Our experience with children, adolescents and adults with residual hip dysplasia has led us to adopt a philosophy of early surgical correction which seeks to normalize hip joint morphology by age 5 or 6 years. The reasoning, methods and early results of this approach are reviewed in this paper.

Anteversion of the acetabulum in developmental dysplasia of the hip: analysis with computed tomography

Acetabular anteversion was measured by using two-dimensional (2-D) computed tomography (CT) scans in 39 dysplastic and 27 normal hips (patient age range, 3-33 years), and averaged 19.7 degrees in the dysplastic hips and 18.1 degrees in the normal hips. There was no statistically significant difference between the two groups, with a wide range of acetabular anteversion values noted in both groups (8-32 degrees ). Although acetabular anteversion may be increased in some patients with developmental dysplasia of the hip (DDH), it is not a universal finding. We believe that assessment and understanding of acetabular anteversion is needed before performing corrective osteotomies for hip dysplasia to optimize results and avoid the complications of acetabular retroversion.

Comparative biomechanical analysis of supracondylar femur fracture fixation: locked intramedullary nail versus 95-degree angled plate

OBJECTIVES

To compare the initial stability of the genucephalic (GSH) intramedullary nail and the 95-degree condylar compression screw and side plate (DCS) for distal femur fractures.

DESIGN

Human cadaveric biomechanical study.

PARTICIPANTS

Twelve matched pairs of fresh frozen human cadaveric femurs.

INTERVENTION

Genucephalic intramedullary nail device (Smith and Nephew Richards, Memphis, TN, U.S.A.) and the 95-degree DCS device (Synthes USA, Paoli, PA, U.S.A.) were compared. Grouped or dispersed screw constructs were tested for each fracture fixation system with progressively more severe simulated fracture patterns.

MAIN OUTCOME MEASUREMENT

Axial and torsional stiffness values.

RESULTS

The DCS plate with the dispersed screw configuration had the greatest torsional stiffness (p < 0.0011). The GSH nail with the grouped screw configuration absorbed more energy (work) during axial loading compared with the plate constructs (p < 0.0007). There were no significant differences in axial or torsional stiffness within treatment groups for fracture patterns of increasing severity.

CONCLUSIONS

Based on the authors' results, the selection of a GSH nail or a DCS plate should not be determined by the severity of the fracture. If a DCS plate construct is selected, the authors recommend a dispersed screw configuration, including the most proximal hole in the plate, to provide superior stiffness in torsional loading and equal stiffness in axial loading when compared with the GSH nail constructs. If a GSH nail is selected, the authors recommend a grouped screw configuration, which absorbed more energy during axial loading compared with the DCS plate constructs and the nail with the dispersed screw configuration.

Skin surface pressure beneath an above-the-knee cast: plaster casts compared with fiberglass casts

Complications related to immobilization in a cast after an injury or an operation may be related to the materials used for the cast or to the techniques of application, or to both. To evaluate the widely held clinical opinion that the use of a fiberglass cast is dangerous and inappropriate when subsequent swelling of the extremity is anticipated, we studied the skin surface pressures that were generated beneath above-the-knee casts made with different materials and applied with different techniques. A prosthetic model of the lower extremity was designed with an expandable calf compartment to simulate swelling after an injury or an operation. With use of this model, we measured the skin surface pressure beneath a plaster-of-Paris cast, a fiberglass cast that had been applied with a standard technique, and a fiberglass cast that had been applied with a stretch-relax technique. The highest mean skin surface pressure after application of the cast (p < 0.001) and after simulated swelling of the limb (p = 0.04) was generated by the fiberglass cast that had been applied with a standard technique. The lowest mean skin surface pressure after application of the cast (p = 0.006), simulated swelling of the limb (p < 0.001), and all subsequent steps of the experimental protocol (p < 0.001) was generated by the fiberglass cast that had been applied with the stretch-relax technique. The mean skin surface pressure generated by the plaster cast and by the fiberglass cast applied with the standard technique did not return to the value before application of the cast until anterior and posterior longitudinal cuts had been made in the cast and the cast had been spread at those cuts. When the fiber-glass cast had been applied with the stretch-relax technique, the mean pressure returned to the baseline value after only an anterior longitudinal cut and spreading at that cut. The principal pitfall of the use of a fiberglass cast is related to the technique of application. When the fiberglass cast had been applied with the standard technique, it generated a mean skin surface pressure that was higher than that associated with the plaster cast and it accommodated simulated swelling poorly. When the fiberglass cast had been properly applied, with the stretch-relax technique, it generated a mean skin surface pressure that was significantly lower (p = 0.006) than that associated with the plaster cast and it better accommodated simulated swelling without the need to sacrifice the structural integrity of the cast.

Modular tibial augmentations in total knee arthroplasty

Proximal tibial bony deficiencies are not uncommon in primary and revision total knee arthroplasty. Modular tibial augmentations were introduced to address these deficiencies. Alterations in strain distribution as a result of medial wedge and block augmentations were evaluated for a modular total knee arthroplasty system in 6 fresh frozen anatomic specimen tibias. Full-field strain patterns were examined using photoelastic coating methods, and high strain regions were evaluated using strain gage rosette techniques. The total knee arthroplasty installations were tested in static physiologic axial and torsional load configurations. The relative effects of sequential wedge and block augmentations compared with the nonaugmented case were statistically analyzed. There were no overall statistical differences in the 3 treatments in terms of maximal (principal) strains. A secondary analysis that evaluated specific location and load pattern combinations established several minor statistical differences along with insights into the manner in which each construct loads the proximal tibia. Although metal wedge augmentation commonly is used, block augmentation seems to be an appropriate alternative from a strain distribution standpoint in cases in which the block geometry better approximates the bony defect.

Is computed tomography useful after simple posterior hip dislocation?

Recent articles and textbooks of orthopaedic traumatology recommend routine computed tomography (CT) scans after successful reduction of simple posterior hip dislocations. This is based on the belief that CT, even in cases with concentric reductions, may identify fractures or intraarticular loose bodies not apparent on standard radiographs. This study was conducted to assess the usefulness of CT after concentric reduction of simple posterior hip dislocations. The hospital database was searched for all traumatic hip dislocations in the past 4 years. Charts and radiographs were reviewed, and only patients with simple posterior hip dislocations (no acetabular or femoral head fractures) and a concentric reduction identified on plain radiographs were included. Twenty-three patients who met these criteria and had subsequent CT scans to evaluate the hip joint were identified. CT scans confirmed the concentric reduction in all patients. Three small occult fractures were identified, and no occult intraarticular loose bodies were found. CT findings did not alter the treatment plan for any of the patients studied. In this small group of patients, CT scanning was not useful after concentric reduction by plain radiography of simple posterior hip dislocations.

Lumbar intervertebral disc transfer. A canine study

STUDY DESIGN

Degenerative lumbar disc disease has been implicated as a cause of low back pain. Current treatment options for low back pain involve nonphysiologic fusion of the involved segments and have variable success rates. This is an experimental study of lumbar intervertebral disc transplantation using a canine surgical model.

OBJECTIVES

This study evaluated the feasibility of lumbar disc transplantation and its effects on disc metabolism and morphology.

METHOD

Eight mature mongrel dogs underwent disc transfer surgeries, in which the L2-L3 and L4-L5 intervertebral discs, with a small segment of adjacent superior and inferior vertebral body, were removed and transposed. The transplanted disc were stabilized by plates or by a flexible cable wire construct using Songer cables (DANEK, Inc., Memphis, TN). Unrestricted activity was allowed postoperatively. At 4 months, the spines were harvested, and the transplanted discs were evaluated biochemically and histologically. Intervening nontransplanted discs served as viable controls and thrice-frozen discs served as nonviable controls. Cell viability was assessed by measuring proteoglycan synthesis and DNA content.

RESULTS

Proteoglycan synthesis (35S uptake normalized to DNA content) was maintained in transplanted anulus fibrosus tissue, but was decreased in nucleus pulposus samples (P < 0.05). DNA content was not altered significantly in the transplanted discs. Histologic analysis of the transplanted discs showed revascularization and remodeling of the bone adjacent to the disc and preservation of the lamellar architecture of the anulus fibrosus. The transplanted nucleus pulposus samples had chondrocyte-like cells present, but the staining characteristics of the nucleus material was variable. The contour of the transplanted disc endplates was irregular in all specimens.

CONCLUSIONS

The structure and function of autograft intervertebral discs were maintained after disc transfer surgery; the transplant discs, however, were not completely normal in either their morphology or their metabolic functioning.