Patricia A. Kramer

Wound Healing Complications in Closed and Open Calcaneal Fractures

Objectives To determine the rate of serious infection in closed and open calcaneal fractures that were treated with open reduction and internal fixation (ORIF) via an extensile lateral approach. Design Retrospective review. Setting Level 1 trauma center. Patients Two groups of patients with calcaneal fractures treated with ORIF via an extensile lateral approach by the senior author are included. The first group contained 341 closed fractures in patients injured during the period 1994–2000. The second group included 39 open calcaneal fractures in patients injured during the period 1989–2000. Main Outcome Measurements The age, sex, pre-existing medical conditions, compliance history, mechanism of injury, soft tissue status, presence of serious infection, and treatment of the infection were recorded for each patient. Data were gathered by review of patient records and by telephone interview when medical records were incomplete. The rate of serious infection in the closed and open samples was determined. A literature review yielded 15 reports that contained sufficient detail to calculate the rate of serious infection. Results Of patients, 1.8% with closed fractures and 7.7% with open fractures experienced serious infections that required intervention beyond oral antibiotics. All of these feet eventually healed their incisions and fractures. The calculations from data obtained from the literature review indicate rates of serious infection of 0–20% for closed and 19–31% for open calcaneal fractures. Conclusions When done correctly in compliant patients, ORIF for calcaneal fractures via the extensile lateral approach (which allows for restoration of calcaneal anatomy after substantial disruption) does not expose the patient to undue risk of serious infection.

Lumbar lordosis of extinct hominins

The lordotic curvature of the lumbar spine (lumbar lordosis) in humans is a critical component in the ability to achieve upright posture and bipedal gait. Only general estimates of the lordotic angle (LA) of extinct hominins are currently available, most of which are based on the wedging of the vertebral bodies. Recently, a new method for calculating the LA in skeletal material has become available. This method is based on the relationship between the lordotic curvature and the orientation of the inferior articular processes relative to vertebral bodies in the lumbar spines of living primates. Using this relationship, we developed new regression models in order to calculate the LAs in hominins. The new models are based on primate group-means and were used to calculate the LAs in the spines of eight extinct hominins. The results were also compared with the LAs of modern humans and modern nonhuman apes. The lordotic angles of australopithecines (41° ± 4), H. erectus (45°) and fossil H. sapiens (54° ± 14) are similar to those of modern humans (51° ± 11). This analysis confirms the assumption that human-like lordotic curvature was a morphological change that took place during the acquisition of erect posture and bipedalism as the habitual form of locomotion. Neandertals have smaller lordotic angles (LA = 29° ± 4) than modern humans, but higher angles than nonhuman apes (22° ± 3). This suggests possible subtle differences in Neandertal posture and locomotion from that of modern humans.

Secondary Soft Tissue Compromise in Tongue-type Calcaneus Fractures

Objectives: Open wounds occur with calcaneus fracture from direct application of force and from tearing along the medial side of the fracture as the tuberosity displaces laterally. Secondary soft tissue injury can also occur from pressure of the displaced fracture fragments. Tongue-type fractures of the calcaneus lead to variable amounts of displacement of the posterior tuberosity. This displacement may threaten the posterior soft tissue envelope. Because many calcaneus fractures are splinted initially and immobilized for several weeks until swelling resolves, failure to acutely recognize the potential for posterior skin breakdown may lead to severe soft tissue morbidity. The purpose of this study was to determine the incidence of posterior skin involvement in tongue-type calcaneus fractures and to determine the patient and fracture characteristics that lead to high-risk situations. Setting: University level I trauma center. Patients/Participants: All tongue-type calcaneus fractures treated at 1 institution between 2002 and 2007 were identified from a trauma registry. Of 954 patients with calcaneal fractures, 139 tongue-type calcaneus fractures in 127 patients formed the study group. Intervention: Patient demographics, comorbidities, injury mechanism, fracture displacement, and time to presentation were evaluated. Those injuries that were associated with posterior, secondary soft tissue breakdown were identified and compared to those without breakdown. Main Outcome Measurements: Univariate analysis and stepwise multinomial logistic regressions were used to identify significant predictors of posterior soft tissue compromise. Results: Twenty-nine fractures (21%) had some degree of posterior skin compromise at presentation, including 12 with threatened skin, 10 with partial thickness breakdown, and 7 with full thickness breakdown. Six soft tissue coverage procedures and one amputation resulted. Patients with posterior skin compromise were less likely to have a fall mechanism (P = 0.001), had significantly greater fracture displacement (P = 0.007), were more likely to smoke (P = 0.039), and were more frequently referred on a delayed basis (P = 0.007). Those with threatened posterior skin who were treated emergently with percutaneous reduction did not progress to soft tissue compromise. Conclusion: A high incidence (21%) of posterior skin compromise occurs in tongue-type calcaneus fractures. These should be treated with immediate reduction, plantarflexion splinting, and close monitoring. Although mechanism, displacement, and time to presentation were significantly correlated with posterior skin involvement, the surgeon should be aware of this potential complicating factor in all tongue-type fractures.

Modern humans are not (quite) isometric

Allometric relationships are important sources of information for many types of anthropological and biological research. The baseline for all allometric relationships is isometry (or geometric similarity), the principal that shape is invariant of size. Here, we formally test for geometric similarity in modern humans, looking at the maximum lengths of four long bones (humerus, radius, femur, and tibia). We use Jolicoeurs multivariate allometry method to examine globally distributed samples of human populations, both collectively and individually. Results indicate that humans are not geometrically similar, although morphological deviations from isometry are small.

Prevalence and distribution of spinal osteoarthritis in women.

Study Design. Retrospective review of lateral spinal thoracolumbar radiographs, obtained to rule out spinal injury after trauma, were scored for osteoarthritis. Objectives. The extent, prevalence, and distribution of spinal osteoarthritis in women aged 20–80 years was determined. Summary of Background Data. Radiographic evidence of disc space narrowing and osteophytosis is one method of assessing osteoarthritis, but population-based surveys of osteoarthritis have been limited due the dangers of exposing human subjects to radiographs. Consequently, the prevalence and the distribution of osteoarthritis in women have not been established. Methods. Average individual disc space narrowing and osteophytosis scores were assessed using an atlas method. Prevalence was determined for decadal age groups and spinal level (T4–L7). Results. The extent of osteoarthritis is weakly associated with age, while the prevalence of osteoarthritis increases with age. Two peaks in osteoarthritis prevalence are apparent: in the mid thoracic and lower lumbar spines. Conclusions. Although few younger women have high average scores, some older women have no radiographic sign of osteoarthritis, while others are severely affected. While the peak in osteoarthritis in the lumbar spine parallels the clinical symptom of low back pain, the more pronounced peak in the mid thoracic does not have a reported corresponding clinical symptom.

Spinal degenerative disk disease (DDD) in female macaque monkeys: epidemiology and comparison with women

Spinal degenerative disk disease (DDD) in a radiographic, cross‐sectional sample of 192 female macaque monkeys, approximately 5–30 years old, is described. The presence and extent of disk space narrowing (DSN) and anterior osteophytosis were assessed with reference to age, average lifetime body mass, and distribution within the thoracolumbar spine. Age was a strong correlate of disk narrowing and osteophytosis, with early signs appearing at equivalent ages in both species and increasing in prevalence thereafter. Macaques showed a far greater prevalence of DDD, especially in the oldest age group, than has been reported in the human data. Body mass was associated with disk narrowing in the macaque, but not with osteophytosis. The two species differed little in the pattern of distribution of DDD along the spine. Our results suggest that bipedality is not the singular, or even the most important, biomechanical factor in the development of human DDD. Rather, others shared postural regimes, e.g., sitting, may be responsible for the onset and progression of DDD in both species. The macaque model could substantially add to the under‐standing and, potentially, treatment of this oftentimes debilitating condition.

Factors influencing osteological changes in the hands and fingers of rock climbers

This study examines the osteological changes in the hands and fingers of rock climbers that result from intense, long‐term mechanical stress placed on these bones. Specifically, it examines whether rock climbing leads to metacarpal and phalange modelling in the form of increased cortical thickness as well as joint changes associated with osteoarthritis. This study also attempts to identify specific climbing‐related factors that may influence these changes, including climbing intensity and frequency of different styles of climbing. Radiographs of both hands were taken for each participant and were scored for radiographic signs of osteoarthritis using an atlas method. Total width and medullary width were measured directly on radiographs using digital calipers and used to calculate cross‐sectional area and second moment of area based on a ring model. We compared 27 recreational rock climbers and 35 non‐climbers for four measures of bone strength and dimensions (cross‐sectional area, second moment of area, total width and medullary width) and osteoarthritis. A chi‐squared test for independence was used to compare climber and non‐climber osteoarthritis scores. For each measure of bone strength climbers and non‐climbers were compared using a manova test. Significant manova tests were followed by principal components analysis (PCA) and individual anova tests performed on principal components with eigenvalues greater than one. A second PCA was performed on the climber subsample and the first principal component was then used as the dependent variable in linear regression variable selection procedures to determine which climbing‐related variables affect bone thickness. The results suggest that climbers are not at an increased risk of developing osteoarthritis compared with non‐climbers. Climbers, however, do have greater cross‐sectional area as well as second moment of area. Greater total width, but not meduallary width, indicates that additional bone is deposited subperiosteally. The strength of the finger and hand bones are correlated with styles of climbing that emphasize athletic difficulty. Significant predictors include the highest levels achieved in bouldering and sport climbing.

Intervertebral disc degeneration in a naturally occurring primate model: radiographic and biomechanical evidence.

Classic degenerative disc disease is a serious health problem worldwide, whose etiological basis—mechanical stimulus, biochemical changes, or natural aging—is poorly understood. Animal models are critical to the study of degenerative disc disease initiation and progression and for attempts to regulate, ameliorate, or eliminate it. The macaque represents a primate model with natural disc degeneration that might serve to advance the field; we aimed to provide radiographic (morphologic) and biomechanical evidence of natural disc degeneration in this model. A factorial study design was used to examine the relationship between the radiographic appearance of disc degeneration and its biomechanical consequences. Eighteen macaques of advanced age (22.3 ± 0.9 years) had radiographs taken to assess the degree of thoracolumbar intervertebral disc degeneration using a standard atlas method. Each spine was harvested and dynamic biomechanical tests were performed. Advancing disc degeneration (degree of disc space narrowing and osteophytosis) was associated with increased stiffness, decreased energy absorption, and increased natural frequency of the intervertebral disc. These associations linking the dynamics of the intervertebral disc and its degree of degeneration are similar to those found in humans. Our results indicate the macaque model with morphologic and biomechanical efficacy could aid in understanding the progression of disc degeneration and in developing therapeutic strategies to prevent or inhibit its course.

Vertebral Bodies or Discs: Which Contributes More to Human-like Lumbar Lordosis?

BackgroundThe attainment of upright posture, with its requisite lumbar lordosis, was a major turning point in human evolution. Nonhuman primates have small lordosis angles, whereas the human spine exhibits distinct lumbar lordosis (30°–80°). We assume the lumbar spine of the pronograde ancestors of modern humans was like those of extant nonhuman primates, but which spinal components changed in the transition from small lordosis angles to large ones is not fully understood.Questions/PurposesWe wished to determine the relative contribution of vertebral bodies and intervertebral discs to lordosis angles in extant primates and humans.MethodsWe measured the lordosis, intervertebral disc, and vertebral body angles of 100 modern humans (orthograde primates) and 56 macaques (pronograde primates) on lateral radiographs of the lumbar spine (humans–standing, macaques–side-lying).ResultsThe humans exhibited larger lordosis angles (51°) and vertebral body wedging (5°) than did the macaques (15° and −25°, respectively). The differences in wedging of the intervertebral discs, however, were much less pronounced (46° versus 40°).ConclusionsThese observations suggest the transition from pronograde to orthograde posture (ie, the lordosis angle) resulted mainly from an increase in vertebral body wedging and only in small part from the increase in wedging of the intervertebral discs.

The effect on energy expenditure of walking on gradients or carrying burdens.

The effectiveness of people walking while carrying burdens and/or on gradients has been of interest to anthropologists for some time. No empirical equation exists, however, to assess the energetic expenditure of individuals traveling downhill with burdens and whether or not all people increase their energetic expenditure over unburdened level travel when carrying relatively light burdens (<20% of body mass) remains unclear. To begin to rectify this lacunae, gait parameters, physiological variables, and the energetic expenditure of 11 adults were assessed as they walked with burdens of 5 and 10 kg on a level treadmill and while they walked unburdened on gradients ±8 and ±16%. These data were then compared to predictive equations and data available from the literature. Velocity and body mass were combined with gradient and burden mass, where appropriate, as independent covariates to create predictive equations, which explained >80% of the variation in energetic expenditure. These new equations are appropriate for predicting energetic expenditure in people carrying burdens of <20% of total body mass or walking up and downhill at gradients of <20%. Am. J. Hum. Biol. 2010.