Paul Toogood

Evaluation of proximal femoral geometry using digital photographs

The morphologic features of the proximal femur are used in preoperative planning prior to total hip arthroplasty. Recent literature evaluating the anatomy of the proximal femur, as it relates to total hip arthroplasty, has relied heavily on radiographs or computed tomography. We used digital photographs to compare 200 cadaveric femora in individuals who died prior to 40 years of age: 25 African‐American males, 25 African‐American females, 25 Caucasian males, 25 Caucasian females. With our technique and definition, the actual angles and dimensions of the proximal femur that we normally rely on during total hip arthroplasty were measured. There were small, but statistically significant differences, between males and females in neck‐shaft angle, neck inclination, and absolute horizontal and vertical offset. Females tended to have a lower neck‐shaft angle and more neck inclination. When standardizing the offset distances with femoral head diameter, the horizontal offset ratio was higher in female specimens. There was no correlation between horizontal and vertical offset. Improved knowledge of the morphology of the proximal femora will assist the surgeon in restoring the geometry of the proximal femur during total hip arthroplasty. This information also supports the concept of modularity of the femoral neck in order to independently adjust neck‐shaft angle, neck inclination, and horizontal offset.

The effect of varus and valgus osteotomies on femoral version.

Background Although seldom described, varus and valgus osteotomies of the proximal femur can affect femoral version. The magnitude of the effect can be predicted with an understanding of the distinction between femoral version and femoral neck inclination. The purpose of this study was to elucidate this relationship. Methods Version, inclination, apparent neck-shaft angle, and true neck-shaft angle were defined and measured in 72 preserved femora. Results Average values were 19.8±11.8 degrees for version versus 14.5±10.1 degrees for inclination (P=0.004), giving a mean difference of 27% between version and inclination, with greater discrepancy with increasing neck-shaft angle. There were high correlations between measured inclination and inclination calculated using version and apparent neck-shaft angle (r=0.96) and true neck-shaft angle (r=0.97), validating our formulaic relationship between these variables. Conclusions We present and validate the concept of inclination, and its relationship with version and neck-shaft angle. This explains the mechanism for a varus osteotomy decreasing anteversion, and a valgus osteotomy increasing anteversion. Clinical Relevance With an understanding of these concepts, a surgeon can incline the femoral neck axis to achieve a desired amount of version, for any given neck-shaft angle. Without this understanding, precise control of the version and neck-shaft angle is difficult.

Periprosthetic Fractures: A Common Problem with a Disproportionately High Impact on Healthcare Resources

The present study evaluated the frequency of periprosthetic fractures and tested the hypothesis that this populations demographics and outcomes are unique as compared with other arthroplasty patients. The National Hospital Discharge Survey provided the raw data. Individuals admitted with a primary TKA, primary THA, or revision TJA were selected. Annual rates were then calculated and demographics and outcomes compared. 30,624 patients were reviewed. The proportion of admissions for periprosthetic fractures ranged from 4.2% to 7.4% annually. As compared to patients admitted for other TJA diagnoses, individuals admitted with periprosthetic fracture were older, were more often female, were more often admitted emergently/urgently, had longer lengths of stay, had higher rates of discharge to places other than home, and had a significantly elevated mortality.

The evaluation of two references for restoring proximal femoral anatomy during total hip arthroplasty

The morphologic features of the proximal femur are used in preoperative planning prior to total hip arthroplasty (THA). In this study we evaluated two references that have been widely used during THA to restore the normal anatomy of the proximal femur: (1) the distance from the lesser trochanter to the center of femoral head and (2) the anatomic relationship between the greater trochanter and the center of femoral head. We used digital photographs to compare 200 cadaveric femora in individuals who died prior to 40 years of age. Preoperative measurement of the distance from lesser trochanter to the center of femoral head from the contralateral hip is accurate to predict the measurement on the operated hip with correlation coefficients (r2) of 0.87. The ratio between femoral head diameter and distance from the lesser trochanter to the center of femoral head was consistent and reliable between genders and sides with an average value of 1.01 ± 0.12. Thus, when the distance from the lesser trochanter to the center of femoral head is not discernible, this ratio can be used as a guide to determine proximal femoral geometry. Conversely, only 59% of the specimens had femoral head centers within 5 mm of the tip of greater trochanter. The correlation between sides of the relationship between the greater trochanter and the center of femoral head was moderate (r2 = 0.46). Therefore, this relationship should not be used as the sole method to determine the normal anatomy of proximal femur. Clin. Anat. 23:312–318, 2010.

Anterior corpectomy via the mini-open, extreme lateral, transpsoas approach combined with short-segment posterior fixation for single-level traumatic lumbar burst fractures: analysis of health-related quality of life outcomes and patient satisfaction

OBJECTIVE The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures. METHODS Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up. RESULTS Twelve patients (7 men, 5 women, average age 42 years, range 22-68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5-8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16-68 months), and average radiographic follow-up was 37 months (range 6-68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0-52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery. CONCLUSIONS Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Are conventional inlet and outlet radiographs obsolete in the evaluation of pelvis fractures

INTRODUCTION The new-generation multidetector computed tomographic (CT) scanners allow for the generation of virtual x-rays from the data acquired during the evaluation of pelvic fractures. Special software allows technicians to obtain the appropriate orientation required for adequate inlet and outlet views, which would eliminate repeat trips to the radiography suite to acquire adequate x-rays. The purpose of this study is to compare the quality virtual x-rays and conventional x-rays that are used in evaluating pelvis fractures. METHODS A retrospective database review was performed to identify patients who were operated on with a diagnosis of pelvis fracture. The inclusion criteria were AO/OTA type B or C pelvic fractures, age older than 18 years, complete set of anteroposterior (AP) pelvis, inlet, and outlet x-rays and a multidetector pelvis CT scan. Virtual AP pelvis, inlet, and outlet views were generated from the CT scan data. Two fellowship-trained orthopedic trauma surgeons reviewed the virtual and conventional studies separately in association with CT scans and graded the quality of the studies on a custom developed questionnaire. RESULTS Twenty patients were eligible for the study. The AP pelvis image quality was similar for both conventional and virtual images except for the rotation of the pelvis, which was improved in the virtual images. The inlet and outlet image quality was better in all domains in the virtual x-ray group when compared with the conventional x-rays. The percentage of adequate inlet and outlet images was higher in the virtual x-ray group when compared with the conventional x-ray group. DISCUSSION The results show that the virtual inlet and outlet images consistently provided higher rates of adequate x-rays when compared with the conventional x-rays. In the evaluation of patients with pelvis fractures, the use of the virtual inlet and outlet views instead of the conventional x-rays may provide some advantages, such as decreased radiation exposure to the patient, reduced overall cost, and reduced repeat x-rays to achieve adequate views. LEVEL OF EVIDENCE Diagnostic study, level V.

Where is the neck?: Alpha angle measurement revisited

Background and purpose — The alpha angle is the most used measurement to classify concavity of the femoral head-neck junction. It is not only used for treatment decisions for hip impingement, but also in cohort studies relating hip morphology and osteoarthritis. Alpha angle measurement requires identification of the femoral neck axis, the definition of which may vary between studies. The original “3-point method” uses 1 single point to construct the femoral neck axis, whereas the “anatomic method” uses multiple points and attempts to define the true anatomic neck axis. Depending on the method used, the alpha angle may or may not account for other morphological characteristics such as head-neck offset. Methods — We compared 2 methods of alpha angle measurement (termed “anatomic” and “3-point”) in 59 cadaver femora and 83 cross-table lateral radiographs of asymptomatic subjects. Results were compared using Bland-Altman plots. Results — Discrepancies of up to 13 degrees were seen between the methods. The 3-point method had an “equalizing effect” by disregarding femoral head position relative to the neck: in femora with high alpha angle, it resulted in lower values than anatomic measurement, and vice versa in femora with low alpha angles. Using the anatomic method, we derived a reference interval for the alpha angle in normal hips in the general population of 30–66 degrees. Interpretation — We recommend the anatomic method because it also reflects the position of the femoral head on the neck. Consensus and standardization of technique of alpha angle measurement is warranted, not only for planar measurements but also for CT or MRI-based measurements.

What ape proximal femora tell us about femoroacetabular impingement: a comparison.

BackgroundHuman hip morphology is variable, and some variations (or hip morphotypes) such as coxa profunda and coxa recta (cam-type hip) are associated with femoroacetabular impingement and the development of osteoarthrosis. Currently, however, this variability is unexplained. A broader perspective with background information on the morphology of the proximal femur of nonhuman apes is lacking. Specifically, no studies exist of nonhuman ape femora that quantify concavity and its variability.Questions/purposesWe hypothesized that, when compared with modern humans, the nonhuman apes would show (1) greater proximal femoral concavity; (2) less variability in concavity; and (3) less sexual dimorphism in proximal femoral morphology.MethodsUsing identical methods, we compared 10 morphological parameters in 375 human femora that are part of the Hamann-Todd collection at the Cleveland Museum of Natural History with 210 nonhuman ape femora that are part of the collection of the Royal Museum for Central Africa, Tervuren, Belgium, and the Muséum National d’Histoire Naturelle, Paris, France.ResultsThe nonhuman apes have larger proximal femoral concavity than modern humans. This morphology is almost uniform without large variability or large differences neither between species nor between sexes.ConclusionsVariability is seen in human but not in nonhuman ape proximal femoral morphology. An evolutionary explanation can be that proximal femoral concavity is more important for the nonhuman apes, for example for climbing, than for modern humans, where a lack of concavity may be related to high loading of the hip, for example in running.

A biomechanical comparison of ipsilateral and contralateral pedicle screw placement for modified triangular osteosynthesis in unstable pelvic fractures.

Objectives: Iliosacral fixation of unstable pelvic fractures does not produce enough stability to allow for immediate postoperative weight bearing. Triangular osteosynthesis creates additional resistance to vertical displacement and rotation. A disadvantage is the loss of the L5/S1 motion segment. We propose a modification of the standard triangular osteosynthesis construct in which the contralateral S1 pedicle is used. As the ipsilateral L5 pedicle is unavailable for fixation in a saw-bones composite pelvic model, we compared ipsilateral and contralateral S1 pedicle screw constructs. We hypothesized that ipsilateral and contralateral S1 pedicle screw constructs would demonstrate no difference in displacement or rotation. Methods: Seven saw bones pelvic models were tested. A 5-mm vertical fracture gap was created through the left sacrum while the pubic symphysis was completely dissociated. Each pelvis was tested sequentially in 4 triangular osteosynthesis configurations: ipsilateral S1 screw with anterior plate, contralateral S1 screw with anterior plate, contralateral S1 screw without anterior plate, and ipsilateral S1 screw without anterior plate. Specimens were cyclically loaded from 100–200 N at 0.25 Hz for 25 cycles and then loaded up to 300 N at 10 mm/min while displacement and rotation at the sacral and pubic fracture sites were measured. Results: There was no difference in any of the displacement measures between ipsilateral and contralateral constructs. When comparing rotation, the contralateral configuration experienced significantly less rotation than the ipsilateral configuration with and without the anterior plate applied. Conclusions: Within the limitations of the current model, contralateral S1 constructs for modified triangular osteosynthesis were biomechanically equal to ipsilateral constructs in preventing displacement and superior in preventing rotation.

Clavicle Fractures: A Review of the Literature and Update on Treatment

Abstract Clavicle fractures are common, and it is important for primary care physicians to be familiar with basic principles of evaluation and management in order to initiate treatment as well as discuss these injuries with patients and consulting orthopedic surgeons. These injuries are almost always the result of trauma (often a direct blow to the shoulder) and occur most often in the young male population. Evaluation begins with a thorough history and physical examination and typically progresses to plain radiographs identifying the fracture site and pattern. These fractures have been classified by Allman into groups I (mid-shaft), II (lateral), and III (medial); this classification, along with fracture characteristics (eg, displacement and comminution) is used to assist with determining the strategy for management. Although nondisplaced fractures continue to be treated conservatively with a simple sling until the fracture is healed according to radiographs and clinical assessment, various forms of open reduction and internal fixation are now commonly used to treat fractures with little or no cortical contact between fragments. Open reduction and internal fixation has shown superior results compared with conservative management in recent trials of management of displaced fractures. Nonunion and malunion are rare, but may be symptomatic in a subset of patients. These complications may be addressed with open reduction and internal fixation, bone grafting, and osteotomy as needed.