Amy Hoang-Kim

Dynamic hip screw compared with external fixation for treatment of osteoporotic pertrochanteric fractures. A prospective, randomized study.

BACKGROUND Although the use of a sliding hip screw is considered to be the preferred treatment for pertrochanteric femoral fractures, we theorized that external fixation could produce clinical outcomes equal to, if not better than, the outcomes obtained with conventional treatment. Furthermore, because external fixation is minimally invasive, we expected a lower rate of morbidity and a reduced need for blood transfusions. Therefore, we compared the two treatments in a clinical trial of elderly patients with pertrochanteric fracture. METHODS Forty consecutive elderly female patients who had a pertrochanteric fracture were randomized to be treated with either fixation with a 135 degrees four-hole sliding hip screw (Group A) or an external fixation device with hydroxyapatite-coated pins (Group B). The inclusion criteria were female gender, an age of at least sixty-five years, an AO/OTA type-A1 or A2 fracture, and a bone mineral density T-score of less than -2.5. There were no differences in patient age, fracture type, bone mineral density, comorbidities, length of hospital stay, or quality of reduction between the two groups. RESULTS The average intraoperative time (and standard deviation) was 64 +/- 6 minutes in Group A and 34 +/- 5 minutes in Group B (p < 0.005). The average number of units of blood transfused postoperatively was 2.0 +/- 0.1 in Group A and none in Group B (p < 0.0001). Group B had less pain five days postoperatively (p < 0.05). Varus collapse of the fracture at six months averaged 6 degrees +/- 8 degrees in Group A and 2 degrees 1 degrees in Group B (p < 0.002). No pin-track infections occurred in Group B. The average Harris hip score at six months was 62 +/- 19 points in Group A and 63 +/- 17 points in Group B. CONCLUSIONS This study showed that external fixation with hydroxyapatite-coated pins is an effective treatment for this fracture in this patient population. The operative time is brief, the blood loss is minimal, the fixation is adequate, and the reduction is maintained over time.

Alendronate improves screw fixation in osteoporotic bone

BACKGROUND Animal studies have demonstrated the efficacy of the use of bisphosphonates to enhance screw fixation in bone. In this prospective, randomized study of pertrochanteric fractures treated with external fixation, we tested whether systemic administration of bisphosphonates would improve the fixation of hydroxyapatite-coated screws implanted in osteoporotic bone. METHODS Sixteen consecutive patients with a pertrochanteric fracture were selected. Inclusion criteria were female gender, an age of at least sixty-five years, and a bone mineral density T-score of less than -2.5 standard deviations. Exclusion criteria included bisphosphonate treatment during the two-year period prior to the fracture. Fractures were fixed with a pertrochanteric fixator and four hydroxyapatite-coated pins. Two pins were implanted in the femoral head (pin positions 1 and 2), and two were placed in the femoral diaphysis (pin positions 3 and 4). The patients were randomized either to therapy with alendronate for a three-month postoperative period (Group A) or to no therapy (Group B). The Group-A patients received an oral dose of 70 mg of alendronate per week. The fixators were removed after three months. RESULTS All of the fractures healed, and no loss of reduction, nonunion, or delayed union was observed. The combined mean extraction torque (and standard deviation) of the pins implanted at positions 1 and 2 (cancellous bone) was 2558 +/- 1103 N/mm in Group A and 1171 +/- 480 N/mm in Group B (p < 0.0005). The combined mean extraction torque of the pins implanted at positions 3 and 4 (cortical bone) was 4327 +/- 1720 N/mm in Group A and 4075 +/- 1022 N/mm in Group B. CONCLUSIONS These data show that weekly systemic administration of alendronate improves pin fixation in cancellous bone in elderly female patients with osteoporosis. We observed a twofold increase in extraction torque with the pins implanted in cancellous bone. These results support the use of alendronate in the treatment of osteoporotic pertrochanteric fractures to improve screw fixation in the femoral head.

CURRENT AUGMENTATION FIXATION TECHNIQUES FOR THE OSTEOPOROTIC PATIENT

Osteoporosis is defined as the deterioration of microarchitecture and overall poor bone quality, which represents a risk of implant fixation failure when patients with osteoporosis are surgically treated. Fragility fractures in elderly patients, typically at the hip, spine and wrist, should be assessed by the orthopaedic surgeon prior to surgery in order to select the most appropriate technique necessary to overcome failures and other complications associated with reduced osteofixation. In this review, advanced methods of augmenting implant fixation in osteoporotic bone are described including polymethylmethacrylate (PMMA), bone grafts, calcium phosphate implants, calcium phosphate cements, calcium phosphate coatings, modified implants and pharmaceutical augmentation concepts. The indication for these techniques should be based on the quantitative assessment of the osteoporotic quality of bone evaluated by dual energy X-ray absorptiometry (DXA).

Hydroxyapatite-coated external fixation pins

A sheep model was developed for the implantation of 84 bicylindrical stainless steel external fixation pins. One-half of the pins were coated with hydroxyapatite, and the rest remained uncoated. A set of 6 pins with the same coating was implanted in the lateral side of the left tibias of 14 sheep, the final insertion torque was measured, and a monolateral external fixator was assembled on the pins. The medial tibial middiaphysis then was exposed and a 5-mm resection osteotomy was done. Sheep were euthanized 6 weeks after surgery, radiographs were taken, and the initial extraction torque was measured on 4 pins from each sheep. Undecalcified sectioning and histologic and histomorphometric analyses were done on the remaining 2 pins. Radiographic pin tract rarefaction was significantly lower in the hydroxyapatite coated pins compared with the uncoated pins. Group average insertion torque was 960 ± 959 Nmm in the hydroxyapatite coated pins and 709 ± 585 Nmm in the uncoated pins. Group average initial extraction torque was 1485 ± 1308 Nmm and 298 ± 373 Nmm, respectively. Bone pin contact was 85.7% ± 8.9% and 50.3% ± 20.4%, respectively, in hydroxyapatite coated and uncoated pins. Bone between the threads was 95.6% ± 5.7% and 80% ± 8.7%, respectively, in hydroxyapatite coated and uncoated pins. Hydroxyapatite coating was effective for improving the bone-to-pin interface.

Osteoporotic pertrochanteric fractures can be successfully treated with external fixation

H ip fractures are the most severe of all fragility fractures. It has been calculated that more deaths are caused by hip fractures than by other common severe diseases such as cancer of the stomach or the pancreas1. Furthermore, regardless of the quality of surgical treatment, hip fractures remain a major cause of disability. The economic implications are clear. In the United States, hip fracture management already costs approximately

The need to standardize functional outcome in randomized trials of hip fracture: a review using the ICF framework.

13.8 billion per year2. In Europe, the average acute hospital cost is approximately €25,000 per fracture and the total care cost is as much as 2.5 times higher3. Approximately 200,000 pertrochanteric fractures (AO/OTA fracture type A1 and A2) per annum occur in the United States alone4. It has been calculated by the United States Census Bureau that, by the year 2020, the average life expectancy will be eighty-two years for women and seventy-four years for men5. This longer life expectancy will be associated with a dramatic increase in the number of pertrochanteric fractures. The functional results of treatment of pertrochanteric fractures are often unsatisfactory. The mortality rate has been reported to be 18% in the first year following operative treatment6. The results are influenced by the inability of the implant to remain well fixed in osteoporotic bone during the time required for fracture-healing. Implant failure and loss of reduction, which often lead to fracture malunion, are frequent complications of osteoporotic pertrochanteric fractures. Because fracture stability is crucial for bone repair, poor bone quality remains a concern that must be given priority when the type of implant is being chosen7. The primary aim of surgical treatment is to obtain good fracture reduction and to maintain this reduction until sufficient stability is provided by the fracture callus. If stable …

Wrist fractures in osteoporotic patients.

Objectives: The choice of ideal outcome assessment is complex with the ever-growing number of possible instruments found in the orthopaedic literature. It is critical to reach a worldwide consensus approach in identifying the specific measures to be used in study designs for evaluating treatment of patients with hip fracture. In this article, we present results from a systematic review of the measures being used currently to assess functional outcome in randomized trials. We used the International Classification of Functioning Disability and Health (ICF) framework for conceptualizing outcome after hip fracture trauma from a body, individual, and societal perspective. Data Sources: Relevant articles from 1980 to 2008 (week 52) were found using PubMed, Ovid MEDLINE, Cochrane, Ovid Healthstar, EMBASE, and CINAHL. Study Selection: Studies were included if (1) patients were older than 65 years and managed postoperatively after a hip fracture and (2) the studies were randomized and in the English language. Data Extraction: The intervention, sample size, follow-up, intention-to-treat analysis, mode of administration, and functional outcome domains and concepts using the ICF were recorded for each study. Data Synthesis: Ninety-seven studies containing 82 different instruments for assessing functional outcome were included. Those trials with a low risk of bias relied upon standardized patient-reported outcomes when compared with those trials with a high risk of bias that adopted more investigator-developed instruments. Nineteen percent of the trials used the Harris hip score, 14% used the Katz activities of daily living index, and 10% used the new mobility score. Conclusions: We believe that standardized patient-reported outcomes should be used to assess functional outcome after hip fracture and more rigor is needed when conducting surgical trials in this area. Variation in outcome measures across trials leads to several problems. Clinicians may not be able to interpret their findings when different measures are used. Researchers will not be able to calculate summary treatment effects. Our findings are based on a process for delineating the categories from within the ICF framework that may serve, in the future, as a comprehensive foundation of content for outcomes in the area of hip fractures.

Fixation of HA-coated unicortical locking screws in a sheep gap model: a comparative biomechanical study.

This issue of the Journal of Orthopaedic Trauma gives an overview of 2 comprehensive workshops held in Bologna, Italy, and Rome, Italy, organized by the Osteoporotic Fracture Campaign*, an initiative of the International Society for Fracture Repair, endorsed by the International Osteoporosis Foundation. The workshops investigated the challenges faced not only by orthopaedic surgeons but also by engineers, radiologists, scientists, and rheumatologists in attempting to find the optimal treatment solution for elderly osteoporotic patients with distal radial fractures. These fractures pose a tremendous challenge to the orthopaedic community as osteoporotic patients have a high rate of unsatisfactory results due to the frequent inability of both conservative and surgical treatment to maintain fracture reduction for the time required for complete bone callus formation. As a consequence, fracture malunion and inadequate functional results are common. Given that the level of activity in the elderly is much higher in 2008 than in the past, it is necessary to assist them in retaining their quality of life. Indeed, action must be taken to improve the current results. These fractures also offer a tremendous opportunity to diagnose the osteoporotic disease. This can be effectively treated with a variety of pharmaceuticals thus reducing the risk of secondary fractures. In a panel discussion, topics ranged from accurate assessment of bone mineral density and issues concerning conservative fracture treatment, the use of fixation augmentation techniques such as hydroxyapatite-coated implants and calcium phosphate cements, and the types of fixation methods which yield the best results. Another issue of great importance is the preoperative use of dual energy x-ray absorptiometry as a tool not only to diagnose the osteoporotic disease but also to help in the selection of the most appropriate surgical treatment. Fracture signs that help to determine whether conservative or surgical treatment is appropriate were also addressed. If a fracture needing reduction is stable after the volar cortices are engaged, it will remain stable. In this case, conservative treatment can be considered. However, when there is comminution and significant displacement, surgical treatment is recommended. This should also be implemented in all patients who had received conservative treatment and in whom fractures redisplaced. Although less invasive fixation methods are still the most commonly used (workshop audience poll 75%), it was suggested that fixed-angle plate fixation implanted through the volar approach will become more popular than the traditional fixation methods, such as percutaneous pinning, external fixation, and plate fixation implanted through the dorsal approach. Advantages of fixed-angle plate fixation include the possibility to adequately expose the fracture site thus obtaining a better reduction. Another important advantage is faster rehabilitation. External fixation also plays a great role in this patient population. Such fixation can be augmented by using screws coated with hydroxyapatite, Kirshner wires, and calcium phosphate cements. It has been reported that although the popularity of fixed-angle plates is dramatically increasing, there is no evidence that it is superior to external fixation. Regardless of the chosen fixation method, the interface between the implant and the bone is of great importance. Implant stability can be improved by using screws coated

Comparing Dynamic Hip Screw to External Fixation for Treatment of Osteoporotic Pertrochanteric Fractures: A Prospective Randomized Study

Objectives: To evaluate whether fixing a locking compression plate (LCP) with hydroxyapatite (HA)-coated screws provides improved biomechanical fixation and healing compared with standard screws under loaded conditions. Methods: Ten sheep were randomly divided into 2 groups. A resection osteotomy of 8 mm was performed in the sheeps right tibiae. Five tibiae were fixed with a 9-hole LCP and 8 standard unicortical locking screws (Group Non-HA), and 5 tibiae were fixed with a 9-hole LCP and 8 HA-coated unicortical locking screws (Group HA). All screws were implanted at the same insertion torque of 4000 Nmm. Three months after surgery, all the sheep were euthanized. Bone segments after screw removal were randomly chosen from each group for histologic analysis (Group Non-HA = 5, Group HA = 5). Results: Mean screw extraction torque was 438 ± 288 Nmm in Group Non-HA (n = 40) and 2317 ± 657 Nmm in Group HA (n = 40) (P < 0.0005). The tibial torque resistance of the resected tibiae was 24 ± 8 Nm in Group Non-HA (n = 5) and 31 ± 3 in Group HA (n = 5) (P = 0.045). In Group Non-HA, histology showed bone resorption and fibrous tissue encapsulation in all the samples, but this was not found in any of the Group HA samples. Conclusions: This study shows that an LCP with HA-coated screws provides improved biomechanical fixation than an LCP with similar standard screws as shown by a 5-fold greater screw extraction torque (P < 0.0005). Furthermore, the higher tibial torque resistance is potentially beneficial for improved gap healing, as shown by higher tibial torque resistance.

Fracture healing and drug therapies in osteoporosis

External fixation has proven to be a viable minimally invasive treatment option for elderly patients with trochanteric fractures. Postoperative complications has limited external fixation in relation to inadequate pin fixation. We compared Orthofix pertrochanteric fixator (OPF) with hydroxyapatite-coated pins to dynamic hip screw (DHS) with AO/ASIF stainless-steel screws in osteoporotic trochanteric fractures. Methods: Forty patients were divided into two groups and randomized for treatment with 135° 4-hole DHS (Group A) or OPF with four hydroxyapatite-coated pins (Group B). Inclusion criteria was: female, age ≥ 65 years, AO fracture type A1 or A2 and BMD lower than -2.5 T-score. All fixators were removed at 3 months. Results: There were no differences in patient age, fracture type, BMD, ASA, hospital stay and reduction quality. Average number of blood transfusions was 2.0 ± 0.1 in Group A, whereas there were none in Group B (p < 0.0001). Operative time was 64 ± 6 minutes in Group A and 34 ± 5 in Group B (p < 0.005). Post-operative femoral neck shaft angle was 134 ± 6° in Group A, and 132 ± 4° in Group B (ns). In Group A, fracture varization at 6 months was 6 ± 8°, in Group B 2 ± 1° (p = 0.002). Harris hip score was 62 ± 20 in Group A and 63 ± 17 in Group B. (n.s.) In Group B, no pin infection occurred. Pin fixation was maintained over time, as shown by no significant difference between pin extraction and corresponding insertion torque. Discussion and Conclusion: In external fixation with hydroxyapatite-coated pins there was no need for blood transfusions and fixation was superior, as confirmed by less varization at long-term.