Soft-tissue principles for orthopaedic surgeons

Meticulous handling of the tissues, reversal of known patient risk factors, and attention to detail can avoid many soft-tissue complications. Prompt management or consultation of a soft-tissue expert may reduce the morbidity and need for extensive reconstructive procedures.     

What's new in hip fractures? Current concepts

Hip fractures have been among the most studied injury patterns in adults. The number of hip fractures is increasing exponentially, and their treatment costs place great economic strain on society. Recently developed hip fracture treatments, emphasizing cost containment, deformity prevention, and evidence-based medicine, are attempts to optimize patient outcomes. In this article, we outline some of these developments with respect to femoral neck and intertrochanteric fractures.     

Accuracy of the axillary projection to determine fracture angulation of the proximal humerus

The accuracy of measuring angulation of stable proximal humerus fractures using the axillary lateral projection was investigated. A closing wedge osteotomy with apex anterior angulation was performed on two cadaveric humeri to simulate a stable surgical neck fracture. One specimen was fixed at 30 degrees angulation and the other at 55 degrees. Axillary radiographs were taken with each specimen articulating with the glenoid of a cadaveric scapula. The humerus was held in neutral rotation. Abduction was set at 30 degrees, 60 degrees, and 90 degrees. In each position of abduction, an axillary lateral radiograph was taken in 30 degrees forward flexion, neutral, and 30 degrees extension to simulate various arm positions. A total of nine radiographs were taken for each specimen. The axillary view is not accurate for measurement of proximal humerus angulation at the arm positions commonly encountered in the trauma setting.     

Clinical pathway for hip fractures in the elderly: the Hospital for Joint Diseases experience

Hip fractures are common injuries in the elderly and are associated with considerable morbidity and mortality. Although technical advances in the treatment of the elderly have resulted in improved fracture fixation and surgical outcomes, clinical pathways have been developed to further improve patient outcome while shortening hospital length of stay after hip fracture. We describe the clinical pathway used since 1990 at the Hospital for Joint Diseases. The outcomes of 747 patients treated before 1990 were compared with outcomes of 318 patients treated at our hospital after initiation of the clinical pathway. Use of the clinical pathway was associated with significant decreases in the acute care hospital length of stay, in-hospital mortality, and 1-year mortality.     

Mismatch of current intramedullary nails with the anterior bow of the femur

OBJECTIVES: The anterior curvature of the femur affects intramedullary nail insertion, revision prosthesis design, and the biomechanics of the proximal femur. Two previous studies, using small numbers of femurs, determined femoral curvature and showed that it was significantly greater than that of the several intramedullary nails they evaluated. In this study, the curvature of 948 femurs (474 matched pairs) was determined and compared with current intramedullary nails. The correlation of femoral curvature to age, gender, femoral size, and race was also evaluated. SETTING: Museum skeletal collections and a hospital biomechanics laboratory. METHODS: The curvature of 892 femurs (446) from the skeletal collections of 2 museums was measured by processing the digital images of the femurs with a computer curve-fitting program. Fifty-six additional, embalmed femurs (28 pairs) from our collection were also digitally imaged and then radiographed and their medullary curvatures similarly determined for comparison. Curvatures of 8 current antegrade intramedullary nails and 3 long-stemmed femoral hip prostheses were obtained from manufacturers and confirmed by measurements from their templates after digitization. RESULTS: We found the average femoral anterior radius of curvature was 120 cm (+/- 36 cm). There was no effect of age on femoral curvature nor was there a correlation between femoral width or femoral length to curvature. Black donor femurs had less curvature than white donor femurs (P < 0.001). There was close correlation (r = 0.967) between the femoral curvatures determined from the digital images and the radiographs. Radii of curvature of the intramedullary nails ranged from 186 to 300 cm (eg, straighter than the femurs). CONCLUSIONS: There was a large mismatch between the curvature of some current antegrade intramedullary nails and the average femur. Although this is only 1 factor affecting nail insertion, the mismatch warrants a reappraisal of these intramedullary nail designs. CLINICAL RELEVANCE: Because ease of intramedullary nail insertion and possibility of cortical comminution are determined by a number of factors including insertion point and fracture location, it appears that a decrease in radii of curvature (less straight) of current nail designs is warranted, particularly for those larger diameter nails designed for hip fracture stabilization that have greater rigidity due to design or material.     

Scaling Marker Position Determines the Accuracy of Digital Templating for Total Hip Arthroplasty

Background

Digital templating systems foster patient-specific measurements for preoperative planning.

Questions/Purposes

We aim (1) to verify the accuracy of a templating system, (2) to describe the effects of scaling marker position on the accuracy of digital templating of the hip, and (3) to provide a practical guide for scaling marker position using patient body mass index (BMI).

Methods

A scaling sphere was placed in five positions along the anterior-posterior axis of an acetabular implant and pelvis phantom, and x-rays were obtained. Each radiograph was templated for the acetabular component and recorded. A retrospective review identified CT scans of preoperative hip arthroplasty cases. The center of the greater trochanter was calculated from these CT scans as the percent distance from the anterior thigh and recorded with the patient’s BMI.

Results

By centering the scaling sphere on the acetabular component, an accurate cup size was achieved. A difference of 3.5 cm in sphere placement resulted in a full cup size magnification error. Positioning the scaling sphere at the level of the pubic symphysis resulted in a difference of four cup sizes. This patient population had an average BMI of 28.72 kg/m² (standard deviation 6.26 kg/m²) and an average position of the center of the greater trochanter of 51% (standard deviation of 6%) from the anterior surface of thigh.

Conclusions

Digital templating relies on scaling marker position to accurately estimate implant size. Based on the findings in this study, scaling markers for hip imaging should be placed laterally, mid-thigh in the anterior-posterior direction for patients with a BMI between 25 and 40 kg/m². If abnormal hip anatomy or extremes of BMI are discovered, then scaling sphere positioning should be optimized on a case-by-case basis. Digital templating systems for total hip arthroplasty must use precisely placed scaling markers at the level of the hip joint to allow for accurate implant size estimation.

     

Calculation of rotational deformity in pediatric supracondylar humerus fractures

Objective Supracondylar humerus fractures (SCHF) are common in the pediatric population. Cubitus varus deformity (CVD) is the most common long-term complication of SCHFs and may lead to elbow instability and deficits in throwing or extension. Distal fragment malrotation in the axial plane disposes to fragment tilt and CVD; however, no simple method of assessing fracture malrotation exists. This study tested a mathematical method of measuring axial plane malrotation in SCHFs based on plain radiographs. Design A pediatric SCHF model was made, and x-rays were taken at known intervals of rotation. Five independent, blinded observers measured these films. Calculated rotation for each data set was compared to the known rotation. The identical protocol was performed for an aluminum phantom. Results The reliability and agreement of the rotation values were good for both models. Conclusions This method is a reliable, accurate, and cost-effective means of calculating SCHF distal fragment malrotation and warrants clinical application. This study was conducted at the NYU Hospital for Joint Diseases. None of the authors received financial support for this study.     

Removal of painful orthopaedic implants after fracture union

BACKGROUND: Persistent pain in the region of implanted hardware following fracture fixation commonly leads to implant removal. This prospective study evaluated patient outcomes and pain reduction following removal of orthopaedic hardware implanted for fracture fixation. METHODS: Sixty patients who had been treated previously for a fracture and complained of pain in the region of the fracture fixation hardware constituted the study cohort. Patients were carefully examined by the treating physician to rule out other causes of pain such as infection and nonunion. Baseline data were recorded preoperatively. Data obtained postoperatively at three, six, and twelve months included a visual analog pain scale score and results on the Short Musculoskeletal Function Assessment Questionnaire and the Medical Outcomes Study Short Form-36. At the one-year interval, a patient satisfaction questionnaire was completed and outcomes were analyzed. RESULTS: There were no complications associated with implant removal surgery. Three patients did not have complete follow-up, leaving a total of fifty-seven patients with complete follow-up. At one year, all patients indicated that they were satisfied, that they would have the procedure done again, and that their overall function had improved. The scores for pain on the visual analog scale decreased from a mean (and standard deviation) of 5.5 +/- 2.5 before hardware removal to 1.3 +/- 1.8 after hardware removal, with an overall improvement at one year of 76% (p = 0.00001). At one year, thirty (53%) of the fifty-seven patients had complete resolution of pain. In addition, the results on the Short Musculoskeletal Function Assessment Questionnaire showed a 43% improvement from baseline (p = 0.0001), and the results on the physical component of the Short Form-36 showed a similar improvement of 40% (p = 0.0001). CONCLUSIONS: Following fracture-healing, removal of hardware is safe with minimal risk. Improvement in pain relief and function can be expected.