Dieter M. Lindskog

The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip.

Failure of fixation of peritrochanteric fractures that have been treated with a fixed-angle sliding hip-screw device is frequently related to the position of the lag screw in the femoral head. A simple measurement has been developed to describe the position of the screw. This measurement, the tip-apex distance, is the sum of the distance from the tip of the lag screw to the apex of the femoral head on an anteroposterior radiograph and this distance on a lateral radiograph, after controlling for magnification. To determine the value of this measurement in the prediction of so-called cutout of the lag screw, 198 peritrochanteric fractures (193 patients) were studied. The minimum duration of follow-up was three months (average, thirteen months), during which period all of the fractures either healed or had failure of the fixation. Of the nineteen failures that were identified, sixteen were due to the device cutting out of the femoral head. The average tip-apex distance was twenty-four millimeters (range, nine to sixty-three millimeters) for the successfully treated fractures compared with thirty-eight millimeters (range, twenty-eight to forty-eight millimeters) for those in which the screw cut out (p = 0.0001). None of the 120 screws with a tip-apex distance of twenty-five millimeters or less cut out, but there was a very strong statistical relationship between an increasing tip-apex distance and the rate of cutout, regardless of all other variables related to the fracture.(ABSTRACT TRUNCATED AT 250 WORDS)

Intramedullary versus extramedullary fixation for the treatment of intertrochanteric hip fractures.

One hundred thirty-one patients (135 fractures) who sustained an intertrochanteric fracture were assigned randomly to treatment with either a sliding hip screw or an intramedullary hip screw and followed up prospectively. In patients with unstable intertrochanteric fractures, the intramedullary device was associated with 23% less surgical time and 44% less blood loss; however, use of the intramedullary hip screw in patients who had a stable fracture pattern required 70% greater fluoroscopic time. Intraoperative complications occurred exclusively in patients in the intramedullary hip screw group. There were no differences in the rates of functional recovery between the two fixation groups.

Unstable Intertrochanteric Hip Fractures in the Elderly

Abstract Unstable intertrochanteric hip fractures account for approximately one quarter of all hip fractures in the elderly and are increasing in frequency. Treatment goals include immediate mobilization while limiting complications. Preoperatively, medical comorbidities should be identified and managed. For stable intertrochanteric hip fractures, consistently good results have been achieved with compression hip screw fixation. However, with more unstable fracture patterns, problems with compression hip screw fixation, such as excessive fracture collapse and implant cutout, increase. For these fractures, adding a trochanteric stabilizing plate or using an axial compression hip screw or intramedullary hip screw is warranted. Surgical care should maximize the patients chance of a successful outcome by realigning the fracture with minimal additional surgical insult, selecting the appropriate implant, and positioning it properly.

Metastatic Disease of the Spine

&NA; Metastatic spine disease accounts for 10% to 30% of new cancer diagnoses annually. The most frequent presentation is axial pain. A thorough spinal examination includes assessment of local tenderness, deformity, limitation of motion, and signs of nerve root or cord compression. Plain radiographs are obtained routinely; for a suspected or known malignancy, radionuclide studies are essential. Magnetic resonance imaging is more specific than bone scans. Computed tomography‐guided biopsy is considered to be safe and accurate for evaluating spinal lesions. Treatment is multidisciplinary, and virtually all treatment is palliative. Management is guided by three key issues: neurologic compromise, spinal instability, and individual patient factors. Site‐directed radiation, with or without chemotherapy, is the mainstay of treating painful lesions that are not impinging on neural elements. New data documenting the benefit of surgical decompression using improved techniques such as anterior approaches have amplified the role of the spine surgeon in the care of these patients.

Bone marrow adipocytes.

ABSTRACT Adipocytes were identified in human bone marrow more than a century ago, yet until recently little has been known about their origin, development, function or interactions with other cells in the bone marrow. Little functional significance has been attributed to these cells, a paradigm that still persists today. However, we now know that marrow adipose tissue increases with age and in response to a variety of physiologic induction signals. Bone marrow adipocytes have recently been shown to influence other cell populations within the marrow and can affect whole body metabolism by the secretion of a defined set of adipokines. Recent research shows that marrow adipocytes are distinct from white, brown and beige adipocytes, indicating that the bone marrow is a distinct adipose depot. This review will highlight recent data regarding these areas and the interactions of marrow adipose tissue (MAT) with cells within and outside of the bone marrow.

Core Needle Biopsies of Musculoskeletal Tumors: Potential Pitfalls

Core needle biopsy is a powerful tool used to diagnose and develop a treatment strategy for musculoskeletal tumors. With accuracy rates reported between 69% and 99%, it is evident that errors in diagnosis occur, and they can lead to devastating consequences. We reviewed pathology reports of preoperative core needle biopsies in an attempt to determine factors associated with false negative diagnoses for the purpose of improving surgical planning. We retrospectively reviewed all office-based core needle biopsies accomplished in our practice over a 6-year period. One hundred nineteen biopsies were identified, of which 82 fulfilled criteria to be included in the study population. The pathologists report of each biopsy was reviewed and categorized based on the findings into 1 of 2 diagnostic groups: neoplastic or nonneoplastic. The results of the biopsies were then compared to the pathology results of the final surgical resection, and the rates and nature of false negative biopsy results (unrecognized malignant pathology) were compared for each group. Seventy-one biopsies were categorized as neoplastic based on the pathology report. No false negative results were found in this group when compared to the final surgical resection pathology. Eleven biopsies were categorized as nonneoplastic, of which 6 were found to be false negatives when compared to the final surgical pathologic diagnosis. The rate of false negative results significantly increased in biopsies whose reports were categorized as nonneoplastic compared to biopsies categorized as neoplastic (P<.0001). We found core needle biopsies of musculoskeletal lesions to be safe and effective in diagnosing pathologic processes. In cases in which analysis of the biopsy specimen did not identify a specific neoplastic process, we found a high incidence of undiagnosed malignancy upon definitive surgical resection. Pathology reports of core needle biopsies that specify only normal, inflammatory, or other nonspecific tissue descriptions should alert the clinician to the increased possibility of a false negative result, and require further tissue analysis.

Genetic alterations in chondrosarcomas – keys to targeted therapies?

BackgroundChondrosarcomas are malignant tumors of chondrocytes and represent the second most common type of primary bone tumors. Within the context of normal chondrogenesis, this review summarizes results from recent research outlining the key molecular changes that occur during the development of this sarcoma type.ResultsCurrent data support the notion that a two-hit scenario, common to many tumors, also underlies chondrosarcoma formation. First, early-stage mutations alter the normal proliferation and differentiation of chondrocytes, thereby predisposing them to malignant transformation. These early-stage mutations, found in both benign cartilaginous lesions and chondrosarcomas, include alterations affecting the IHH/PTHrP and IDH1/IDH2 pathways. As they are not observed in malignant cells, mutations in the EXT1 and EXT2 genes are considered early-stage events providing an environment that alters IHH/PTHrP signaling, thereby inducing mutations in adjacent cells. Due to normal cell cycle control that remains active, a low rate of malignant transformation is seen in benign cartilaginous lesions with early-stage mutations. In contrast, late-stage mutations, seen in most malignant chondrosarcomas, appear to induce malignant transformation as they are not found in benign cartilaginous lesions. These late-stage mutations primarily involve cell cycle pathway regulators including p53 and pRB, two genes that are also known to be implicated in numerous other human tumor types.ConclusionsNow the key genetic alterations involved in both early and late stages of chondrosarcoma development have been identified, focus should be shifted to the identification of druggable molecular targets for the design of novel chondrosarcoma-specific therapies.

Pathologic fractures through benign bone lesions in children and adolescents

Pathologic fractures through benign bone lesions in children and adolescents should be approached in a systematic fashion in order to ensure appropriate management. The etiology, natural history, and treatment of the underlying abnormality must be taken into account when treating these fractures because the treatment of the fracture will often be altered by the presence of the lesion and vice versa. Most pathologic fractures through benign lesions can be treated closed; however, there are certain circumstances in which open treatment is advisable. A thorough and thoughtful evaluation of the patient who presents with a pathologic fracture through a benign lesion will help lead to an optimal outcome.

Evaluation of bone mineral density and metabolic abnormalities associated with low-energy hip fractures

Background Low-energy hip fractures are markers for osteoporosis. Despite a recent call for better evaluation of this issue, there is a lack of data regarding the metabolic abnormalities found in these patients and how it relates to their bone density. Additionally, no clear guidelines have been published for the evaluation of osteoporosis in these patients. We characterize the metabolic abnormalities seen in this patient population and suggest an effective screening protocol. Methods Thirty-one patients with low-energy hip fractures not receiving osteoporosis treatment were evaluated with bone density scans and a serum metabolic evaluation consisting of a 25-hydroxyvitamin D level, parathyroid hormone level, and calcium level. The relationship of metabolic abnormalities to bone density values was evaluated. Results Most of the patients presenting with low-energy hip fractures had metabolic abnormalities associated with low bone density. The femoral neck T-scores averaged −2.3. Fifty-three percent (16/30) of patients had low levels of vitamin D and 83% (25/30) of patients had evidence of secondary hyperparathyroidism (PTH >25 nleq/ml). We also found relatively poor correlations of bone density T-scores to parathyroid hormone and vitamin D levels (r=−0.38 and −0.05). Conclusion Most patients presenting with low energy hip fractures have severe metabolic abnormalities associated with low bone density. Due to the poor correlation between bone density T-scores and the serum levels of parathyroid hormone and vitamin D, appropriate osteoporosis evaluation of this patient population requires both bone density evaluation and serum metabolic evaluation of 25-hydroxyvitamin D, PTH, and calcium levels.

Bilateral atypical femur fractures without bisphosphonate exposure

Atypical femur fractures have common radiographic features that set them apart from more typical higher-energy subtrochanteric femur fractures. They are noncomminuted, transverse fractures with medial spiking of the femoral cortex and increased lateral cortical thickness. These fractures have been associated in the literature with the use of bisphosphonate medications. This case describes bilateral atypical femur fractures in a patient with a medical history devoid of bisphosphonate use. We present his history, co-morbidities, and subsequent treatment. From this case, we call attention to bisphosphonate use as not the only cause of subtrochanteric femur fractures with atypical features and highlight that some patients may sustain these injuries even bilaterally without use of the medications. In addition, it is important to identify this fracture type and obtain imaging of the contralateral femur to facilitate prophylactic treatment if needed.