Temperature rise during reamed tibial nailing

An in vivo study to investigate an original intramedullary bone graft harvesting technology

BACKGROUND

Harvesting bone graft (BG) from the intramedullary canal to treat bone defects is largely conducted using the Reamer-Irrigator-Aspirator (RIA) system. The RIA system uses irrigation fluid during harvesting, which may result in washout of osteoinductive factors. Here, we propose a new harvesting technology dedicated to improving BG collection without the potential washout effect of osteoinductive factors associated with irrigation fluid. This novel technology involves the conceptual approach of first aspirating the bone marrow (BM) with a novel aspirator prototype, followed by reaming with standard reamers and collecting the bone chips with the aspirator (reaming-aspiration method, R-A method). The aim of this study was to assess the harvesting efficacy and osteoinductive profile of the BG harvested with RIA 2 system (RIA 2 group) compared to the novel harvesting concept (aspirator + R-A method, ARA group).

METHODS

Pre-planning computed tomography (CT) imaging was conducted on 16 sheep to determine the femoral isthmus canal diameter. In this non-recovery study, sheep were divided into two groups: RIA 2 group (n = 8) and ARA group (n = 8). We measured BG weight collected from left femur and determined femoral cortical bone volume reduction in postoperative CT imaging. Growth factor and inflammatory cytokine amounts of the BGs were quantified using enzyme-linked immunosorbent assay (ELISA) methods.

RESULTS

The use of the stand-alone novel aspirator in BM collection, and in harvesting BG when the aspirator is used in conjunction with sequential reaming (R-A method) was proven feasible. ELISA results showed that the collected BG contained relevant amounts of growth factors and inflammatory cytokines in both the RIA 2 and the ARA group.

CONCLUSIONS

Here, we present the first results of an innovative concept for harvesting intramedullary BG. It is a prototype of a novel aspirator technology that enables the stepwise harvesting of first BM and subsequent bone chips from the intramedullary canal of long bones. Both the BG collected with the RIA 2 system and the aspirator prototype had the capacity to preserve the BG's osteoinductive microenvironment. Future in vivo studies are required to confirm the bone regenerative capacity of BG harvested with the innovative harvesting technology.

Reaming the intramedullary canal during tibial nailing does not affect in vivo intramuscular pH of the anterior tibialis

Many investigations have evaluated local and systemic consequences of intramedullary (IM) reaming and suggest that reaming may cause, or exacerbate, injury to the soft tissues adjacent to fractures. To date, no study has examined the effect on local muscular physiology as measured by intramuscular pH (IpH). Here, we observe in vivo IpH during IM reaming for tibia fractures.

Methods

Adults with acute tibia shaft fractures (level 1, academic, 2019-2021) were offered enrollment in an observational cohort. During IM nailing, a sterile, validated IpH probe was placed into the anterior tibialis (<5 cm from fracture, continuous sampling, independent research team). IpH before, during, and after reaming was averaged and compared through repeated measures ANOVA. As the appropriate period to analyze IpH during reaming is unknown, the analysis was repeated over periods of 0.5, 1, 2, 5, 10, and 15 minutes prereaming and postreaming time intervals.

Results

Sixteen subjects with tibia shaft fractures were observed during nailing. Average time from injury to surgery was 35.0 hours (SD, 31.8). Starting and ending perioperative IpH was acidic, averaging 6.64 (SD, 0.21) and 6.74 (SD, 0.17), respectively. Average reaming time lasted 15 minutes. Average IpH during reaming was 6.73 (SD, 0.15). There was no difference in IpH between prereaming, intrareaming, and postreaming periods. IpH did not differ regardless of analysis over short or long time domains compared with the duration of reaming.

Conclusions

Reaming does not affect IpH. Both granular and broad time domains were tested, revealing no observable local impact.

Cellular activation status in femoral shaft fracture hematoma following different reaming techniques - A large animal model

The local inflammatory impact of different reaming protocols in intramedullary nailing has been sparsely investigated. We examined the effect of different reaming protocols on fracture hematoma (FH) immunological characteristics in pigs. To do so, a standardized midshaft femur fracture was induced in adult male pigs. Fractures were treated with conventional reamed femoral nailing (group RFN, n = 6); unreamed femoral nailing (group UFN, n = 6); reaming with a Reamer Irrigator Aspirator device (group RIA, n = 12). Animals were observed for 6 h and FH was collected. FH-cell apoptosis and neutrophil receptor expression (Mac-1/CD11b and FcγRIII/CD16) were studied by flow cytometry and local temperature changes were analyzed. The study demonstrates that apoptosis-rates of FH-immune cells were significantly lower in group RIA (3.50 ± 0.53%) when compared with non-RIA groups: (group UFN 12.50 ± 5.22%, p = 0.028 UFN vs. RIA), (group RFN 13.30 ± 3.18%, p < 0.001, RFN vs. RIA). Further, RIA-FH showed lower neutrophil CD11b/CD16 expression when compared with RFN (mean difference of 43.0% median fluorescence intensity (MFI), p = 0.02; and mean difference of 35.3% MFI, p = 0.04, respectively). Finally, RIA induced a transient local hypothermia and hypothermia negatively correlated with both FH-immune cell apoptosis and neutrophil activation. In conclusion, immunologic changes observed in FH appear to be modified by certain reaming techniques. Irrigation during reaming was associated with transient local hypothermia, decreased apoptosis, and reduced neutrophil activation. Further study is warranted to examine whether the rinsing effect of RIA, specific tissue removal by reaming, or thermal effects predominantly determine local inflammatory changes during reaming.

An old unicondylar tibial plateau fracture (Schatzker type III) with tibial shaft fracture: A case report

Introduction

Case presentation

Clinical discussion

Conclusion

•

Unicondylar tibial plateau fractures with tibial shaft fractures are extremely rare in the elderly.

•

Traditional double plate internal fixation seriously affected soft tissue and bone healing.

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The use of plates in combination with intramedullary nails can reduce the destruction of soft tissue and fix both the tibial plateau and the tibial shaft.

'Extended tibia osteotomy': a technical tip for removal of incarcerated reamer with broken guide wire bead during tibia nailing and literature review

Intramedullary nailing has become a standard of care for tibia fractures. Reaming is an essential part of this technique due to its multiple advantages like a better fit and earlier union. In young bone, with a narrow cortical canal, incarceration and breakage of reamer is a possibility. This can be removed with a ball-tip guidewire. In our case, the broken incarcerated reamer was complicated by a broken ball-tip of the guidewire, leading us to invent a novel medial tibial osteotomy window for the reamer removal. This can be a handy tool for a stuck surgeon intraoperatively.

Intramedullary tissue cultures from the Reamer-Irrigator-Aspirator system for diagnosing fracture-related infection

Fracture-related infection (FRI) is a serious complication following musculoskeletal trauma. Accurate diagnosis and appropriate treatment depend on retrieving adequate deep tissue biopsies for bacterial culture. The aim of this cohort study was to compare intraoperative tissue cultures obtained by the Reamer-Irrigator-Aspirator system (RIA)-system against standard tissue cultures obtained during the same surgical procedure. All patients had long bone fractures of the lower limbs and were assigned to the FRI or Control group based on the FRI consensus definition. The FRI group consisted of 24 patients with confirmed FRI and the Control group consisted of 21 patients with aseptic nonunion or chronic pain (in the absence of other suggestive/confirmatory criteria). Standard tissue cultures and cultures harvested by the RIA-system showed similar results. In the FRI group, standard tissue cultures and RIA cultures revealed relevant pathogens in 67% and 71% of patients, respectively. Furthermore, in four FRI patients, cultures obtained by the RIA-system revealed additional relevant pathogens that were not found by standard tissue culturing, which contributed to the optimization of the treatment plan. In the Control group, there were no false-positive RIA culture results. As a proof-of-concept, this cohort study showed that the RIA-system could have a role in the diagnosis of FRI as an adjunct to standard tissue cultures. Since scientific evidence on the added value of the RIA-system in the management of FRI is currently limited, further research on this topic is required before its routine application in clinical practice.

Successful fifth metatarsal bulk autograft reconstruction of thermal necrosis post intramedullary fixation

Reamed intramedullary (IM) screw fixation for proximal fifth metatarsal fractures is technically challenging with potentially devastating complications if basic principles are not followed. A case of an iatrogenic fourth-degree burn after elective reamed IM screw fixation of a proximal fifth metatarsal fracture in a high-level athlete is reported. The case was complicated by postoperative osteomyelitis with third-degree soft-tissue defect. This was successfully treated with staged autologous bone graft reconstruction, tendon reconstruction, and local bi-pedicle flap coverage. The patient returned to competitive-level sports, avoiding the need for fifth ray amputation. Critical points of the IM screw technique and definitive reconstruction are discussed. Bulk autograft reconstruction is a safe and effective alternative to ray amputation in segmental defects of the fifth metatarsal.Level of evidence V.

Effect of Nail Size, Insertion, and Δ Canal-Nail on the Development of a Nonunion After Intramedullary Nailing of Femoral Shaft Fractures

OBJECTIVE

To determine whether intramedullary nail (IMN) diameter, antegrade versus retrograde insertion, or the difference between the canal and IMN diameter affect femoral shaft fracture healing.

DESIGN

Retrospective analysis of a prospective database.

SETTING

Level One Regional Trauma Center.

PATIENTS/PARTICIPANTS

Seven hundred thirty-three femoral shaft fractures (OTA/AO 32) treated with an IMN between 1999 and 2017. After exclusion criteria, 484 fractures remained in the final analysis.

INTERVENTION

Closed section, cannulated, interlocked, titanium alloy IMN using a reamed insertion technique.

MAIN OUTCOME MEASUREMENTS

Nonunion, IMN size (10, 11.5, and 13 mm), antegrade versus retrograde insertion, Δ canal-nail diameter (ΔD) after reaming (<1, 1-2, or >2 mm).

RESULTS

IMN diameters used were as follows: 314/10 mm (64%), 137/11.5 mm (28%), and 33/13 mm (8%). Forty-five percent were placed in antegrade versus 55% retrograde. Four hundred fifty-six fractures (94.2%) healed uneventfully. There were no IMN failures. 10/484 IMNs (2%) had broken interlocking screws; only 4 were associated with a NU. Average time to union was 23 weeks (12-119). Twenty-eight (5.8%) developed NU. There was no statistical correlation between (1) the NU rate and IMN diameter: 10 mm, 6.3%; 11.5 mm, 5.1%; 13 mm, 3% (P = 0.8, power = 0.85), (2) the NU rate and ΔD: 7.1% <1 mm, 5.6% 1-2 mm, 20% >2 mm (P = 0.36), (3) the NU rate and fracture location: Prox = 11%, Mid = 5%, Dist = 3% (P = 0.13), or (4) the NU rate and antegrade (7.2%) versus retrograde (4.2%) insertion (P = 0.24).

CONCLUSION

Similar healing rates occurred regardless of IMN diameter, Δ canal-nail diameter after reaming, or insertion site. This indicates that a closed section, cannulated, interlocked, titanium alloy IMN with a diameter of 10 mm can be considered the standard diameter for the treatment of acute femoral shaft fractures, regardless of entry point. This should be associated with less reaming and therefore shorter operative times, and possibly less hospital implant inventories as well. Larger diameter IMN should be reserved for revision surgery.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Thermal Osteonecrosis Caused by Bone Drilling in Orthopedic Surgery: A Literature Review

Thermal osteonecrosis is the in situ death of bone tissue as a result of excessively high temperatures. While the exact temperature at which thermal osteonecrosis occurs has not yet been determined, 50°C is the accepted critical value, as bone regeneration is almost completely impaired from this point on. Thermal osteonecrosis is a significant concern in orthopedic surgery, as it can compromise the bone-implant interface in fracture fixation, which, by definition, is a complication.

A literature review was undertaken of the pertinent literature concerning heat generation from bone drilling and how this heat affects bone tissue. The Pubmed, ScienceDirect, and secondary (Cochrane Library) databases were searched up to December 2017 using keywords with the appropriate use of Boolean operators. Both simple text word searching and thesaurus searching were used to maximize the number of relevant articles retrieved. Reference tracking was performed via the retrieved articles to further extend the boundaries of the search. The level of evidence was Level V.

It was identified that factors affecting heat generation during bone drilling were multifactorial and did not act independently of each other. Good quality evidence exists that both bone drilling parameters and the drill itself affect heat generation in bone during bone drilling. However, external irrigation is the most important variable and should always be used to keep the bone temperature below the critical value of 50°C.

Future studies should focus on how the parameters of bone drilling interact with each other and how this influences heat generation in bone drilling. There is also a lack of in vivo studies on the human bone; this too should be further investigated.

Salvage of an osteocutaneous thermonecrosis secondary to tibial reaming by the induced membrane procedure

Osteocutaneous thermonecrosis is a rare but devastating complication of tibial reaming, which can cause large and infected bone and cutaneous defects. The case presented here illustrates that the induced membrane technique described by Masquelet is a valuable option in treating this complication.

Diagnostic use of intramedullary reaming biopsy in metastatic long bone disease

INTRODUCTION Bone is the third most common site of metastasis. A histological diagnosis is important in guiding therapy and prognosis. In up to 15% of cases of metastatic disease, the primary tumour remains unknown. This emphasises the importance of adequate, reliable and accurate sampling when performing any type of biopsy. Reaming biopsy is commonly performed during intramedullary nailing of metastatic long-bone disease but there is little published evidence on the diagnostic use and reliability of this technique. AIMS AND METHODS We reviewed 49 cases of confirmed metastatic bone disease to determine adequacy for analysis, diagnostic accuracy and factors affecting reliability. RESULTS Adequate tissue for histopathological analysis was obtained in 96% of cases but metastasis was confirmed in only 51% of cases. The presence of a pathological fracture had no effect on accuracy of the results but metastasis was more likely to be missed in the presence of tissue crushing and or necrosis (P = 0.015). DISCUSSION This study determines the use and accuracy of bone reaming biopsy in metastatic disease and, to the best of our knowledge, is the only study determining the effect of additional factors such as the presence of a pathological fracture and tissue necrosis or crushing on the diagnostic accuracy of this technique. CONCLUSIONS In spite of adequate tissue sampling, the diagnostic accuracy and, hence, reliability of intramedullary reaming biopsy in metastatic bone disease is less than optimal. A reaming histopathology report suggesting no evident metastasis should always be taken in clinical context.

Intramedullary Nailing of Tibial Shaft Fractures: Size Matters

OBJECTIVES

To determine optimal ratio of intramedullary nail diameter to tibial canal diameter that leads to reliable and timely healing in tibial shaft fractures.

DESIGN

Retrospective case series.

SETTING

Level I trauma center.

PATIENTS

One hundred thirty-three fractures in 132 patients with tibial shaft fractures that underwent intramedullary nailing as definitive fixation were identified between June 2004 and July 2012 at our level I trauma center. Of these, 78 had serial radiographs out to 12 months that could be analyzed for radiographic healing with an average age of 37 years old (range 16-86 years). There were 52 males and 26 females.

INTERVENTION

All patients underwent intramedullary nailing of the tibia with documentation of both the diameter of the nail and radiographic canal width at the isthmus to determine the nail to canal ratio.

MAIN OUTCOME MEASURES

Patients were followed with serial radiographs for at least 12 months to determine time to healing as a function of nail to canal ratio. The senior author assessed healing at 3, 6, 9, and 12 months using RUST criteria.

RESULTS

Patients with an intramedullary nail to canal diameter ratio of less than 0.8 or greater than 0.99 were 4.4 times more likely not to heal than patients with a ratio of between 0.8 and 0.99.

CONCLUSION

The ideal intramedullary nail to tibial canal diameter ratio to optimize tibial shaft fracture healing is between 0.8 and 0.99.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Expert tibia nail for subtrochanteric femoral fracture to prevent thermal injury

INTRODUCTION

Subtrochanteric femoral fractures are relatively uncommon, accounting for 7-15% of all hip fractures and treatment of these fractures are considered challenge for orthopaedic surgeons. Although several treatment options are reported with up to 90% of satisfactory results, the choice of the appropriate implant is still a matter of debate. Some authors reported thermal injury after reaming for intramedullary nail fixation in patients with narrow medullary canal.

PRESENTATION OF CASE

A 21-year-old female patient was admitted to our hospital because of right subtrochanteric femoral fracture. The narrowest diameter of medullary canal of her femur was about 7mm but she refused open reduction and internal fixation with plate due to large scar formation. We used expert tibia nail instead of femoral intramedullary nail to prevent thermal injury.

DISCUSSION

Subtrochanteric femoral fractures are difficult to treat because of their biomechanical and anatomical characteristics. Although several implants are reported for the surgical treatment of these fractures, intramedullary nails have been advocated due to their biological and biomechanical advantages. However, under certain circumstances with associated injury or anatomic difference we might consider another treatment options.

CONCLUSION

Expert tibia nail may be considered one of the treatment options for subtrochanteric femoral fracture with narrow medullary canal. We also emphasize the importance of preoperative evaluation of the medullary canal size for these risky fractures.

Comparison of our self-designed rotary self-locking intramedullary nail and interlocking intramedullary nail in the treatment of long bone fractures

Objective

The purpose of this study is to compare the clinical effects of our self-designed rotary self-locking intramedullary nail (RSIN) and interlocking intramedullary nail (IIN) for long bone fractures.

Methods

A retrospective study was performed in 1,704 patients who suffered bone fractures and underwent RSIN or IIN operation in our hospital between March 1999 and March 2013, including 494 with femoral fractures, 572 with humeral fractures, and 638 with tibial fractures. Among them, 634 patients were followed up for more than 1 year. The operative time, intraoperative blood loss, postoperative complications, healing rate, and the excellent and good rate of functional recovery were compared between two groups.

Results

Compared with IIN group, RSIN group exhibited significantly shorter operative time and less intraoperative blood loss no matter for humeral, femoral, or tibial fractures (all p < 0.001). The healing rate in patients with more than 1 year follow-up was significantly higher in RSIN group for femoral and tibial fractures (both p < 0.05). In RSIN group, no nail breakage or loosening occurred, but radial nerve injury and incision infection were respectively observed in one patient with humeral fracture. In IIN group, nail breakage or loosening occurred in 7 patients with femoral fractures and 16 patients with tibial fractures, radial nerve injury was observed in 8 patients with humeral fractures, and incision infection was present in 2 patients with humeral fractures and 1 patient with femoral fracture. The complication rate of IIN group was significantly higher than that of RSIN group (p < 0.05). However, there were no significant differences in the excellent and good rate of shoulder, elbow, knee, and ankle joint functional recovery between RSIN group and IIN group.

Conclusion

RSIN may be a reliable and practical alternative method for the treatment of long bone fractures.

Subaquatic reaming during arthrodesis of the first metatarsophalangeal joint to prevent thermal necrosis of bone

When performing fusions of the first metatarsophalangeal joint, it has been hypothesized that the use of a cup and cone reamer may cause thermal necrosis, leading to potential nonunion. The friction created by the reamer spinning against the bone has been shown to cause elevations of temperatures capable of causing thermal necrosis. Failing to cool the bony-reamer interface, or doing so inadequately with a bulb syringe, increases the patient's odds of experiencing a nonunion. The authors describe a simple technique that prevents significant temperature elevations at the reamer-bony interface, decreasing the potential for thermal necrosis and increasing the likelihood of successful fusion. The authors have performed this procedure for several patients without complications.

Cortical bone drilling and thermal osteonecrosis

BACKGROUND

Bone drilling is a common step in operative fracture treatment and reconstructive surgery. During drilling elevated bone temperature is generated. Temperatures above 47°C cause thermal osteonecrosis which contributes to screw loosening and subsequently implant failures and refractures.

METHODS

The current literature on bone drilling and thermal osteonecrosis is reviewed. The methodologies involved in the experimental and clinical studies are described and compared.

FINDINGS

Areas which require further investigation are highlighted and the potential use of more precise experimental setup and future technologies are addressed.

INTERPRETATION

Important drill and drilling parameters that could cause increase in bone temperature and hence thermal osteonecrosis are reviewed and discussed: drilling speed, drill feed rate, cooling, drill diameter, drill point angle, drill material and wearing, drilling depth, pre-drilling, drill geometry and bone cortical thickness. Experimental methods of temperature measurement during bone drilling are defined and thermal osteonecrosis is discussed with its pathophysiology, significance in bone surgery and methods for its minimization.

Reamer-irrigator-aspirator indications and clinical results: a systematic review

BACKGROUND

The 'reamer-irrigator-aspirator' (RIA) is an innovation developed to reduce fat embolism (FE) and thermal necrosis (TN) that can occur during reaming/nailing of long-bone fractures. Since its inception its indications have expanded to include the treatment of long-bone osteomyelitis and as a harvester of bone graft/mesenchymal stem cells (MSCs).

METHODS

This study involved a systematic review, via Pubmed® and Google Scholar®, of English language sources (nine non-clinical studies, seven clinical studies and seven case reports) using the keywords: 'reamer', 'irrigator', 'aspirator' (1st May 2010). Sources were reviewed with reference to the RIAs efficacy in (1) preventing FE/TN, (2) treating long-bone osteomyelitis, (3) harvesting bone graft/MSCs, and (4) operating safely. Experimental data supports the use of the RIA in preventing FE and TN, however, there is a paucity of clinical data.

CONCLUSIONS

The RIA is a reliable method in achieving high volumes of bone graft/MSCs, and high union rates are reported when using RIA bone-fragments to treat non-unions. Evidence suggests possible effectiveness in treating long-bone osteomyelitis. The RIA appears relatively safe, with a low rate of morbidity provided a meticulous technique is used. When complications occur they respond well to conventional techniques. The RIA demands further investigation especially with respect to the optimal application of MSCs for bone repair strategies.

The biology of intramedullary reaming

In this review we focus on the local biologic and physiologic effects of intramedullary reaming of long bones. Among the topics discussed are the consequences for vascularity, as well as the pathophysiology of intramedullary pressure generation and temperature increase. Reaming techniques and their suggested effects on bone formation are outlined. Moreover, techniques for avoiding local and systemic complications are summarized.

Treatment of long bone intramedullary infection using the RIA for removal of infected tissue: indications, method and clinical results

Treatment of intramedullary infections of long bones is based upon the principles of surgical debridement, irrigation, fracture site stabilization, soft tissue coverage, and antibiotic administration. Reaming of the medullary canal is an essential component of surgical debridement because it removes intramedullary debris and infected bone surrounding the removed intramedullary device and within the intramedullary canal. The Reamer-Irrigator-Aspirator (RIA) has distinct features that appear to be beneficial for management of intramedullary infections. It allows reaming under simultaneous irrigation and aspiration, which minimizes the residual amount of infected fluid and tissue in the medullary canal and the propagation of infected material. The disposable reamer head is sharp, which combined with the continuous irrigation may attenuate the increased temperature associated with reaming and its potential adverse effects on adjacent endosteal bone. The disadvantage of the RIA is increased cost because of use of disposable parts. Potential complications can be avoided by detailed preoperative planning and careful surgical technique. The RIA should be used with caution in patients with narrow medullary canals and in infections involving the metaphysis or a limited part of the medullary canal. Reaming of the canal is performed with one pass of the RIA under careful fluoroscopic control. Limited information is available in the literature on the results of the RIA for management of intramedullary infections of long bones; however preliminary results are promising. The RIA device appears to be an effective and safe tool for debridement of the medullary canal and management of intramedullary infections of the long bones. Further research is needed to clarify the exact contribution of the RIA in the management of these infections.

Establishment of a preclinical ovine model for tibial segmental bone defect repair by applying bone tissue engineering strategies

Currently, well-established clinical therapeutic approaches for bone reconstruction are restricted to the transplantation of autografts and allografts, and the implantation of metal devices or ceramic-based implants to assist bone regeneration. Bone grafts possess osteoconductive and osteoinductive properties; however, they are limited in access and availability and associated with donor-site morbidity, hemorrhage, risk of infection, insufficient transplant integration, graft devitalization, and subsequent resorption resulting in decreased mechanical stability. As a result, recent research focuses on the development of alternative therapeutic concepts. The field of tissue engineering has emerged as an important approach to bone regeneration. However, bench-to-bedside translations are still infrequent as the process toward approval by regulatory bodies is protracted and costly, requiring both comprehensive in vitro and in vivo studies. The subsequent gap between research and clinical translation, hence, commercialization, is referred to as the "Valley of Death" and describes a large number of projects and/or ventures that are ceased due to a lack of funding during the transition from product/technology development to regulatory approval and subsequently commercialization. One of the greatest difficulties in bridging the Valley of Death is to develop good manufacturing processes and scalable designs and to apply these in preclinical studies. In this article, we describe part of the rationale and road map of how our multidisciplinary research team has approached the first steps to translate orthopedic bone engineering from bench to bedside by establishing a preclinical ovine critical-sized tibial segmental bone defect model, and we discuss our preliminary data relating to this decisive step.

Osteocutaneous thermal necrosis of the leg salvaged by TSF/Ilizarov reconstruction. Report of 7 patients

Injudicious reaming of the tibial shaft can lead to extreme local hyperthermia, which in turn can result in the rare but catastrophic complication of segmental bone and soft tissue necrosis (osteocutaneous thermal necrosis). This is a retrospective study showing osteocutaneous thermal necrosis occurring after tibial intramedullary reaming salvaged by Ilizarov reconstruction in seven patients from the collective experience of four limb reconstruction centres. All patients were males, with an average age of 51.8 years (range, 30-70 years), who had undergone intramedullary reaming during the treatment of closed tibial fractures. In all patients, circumferential bone and variable contiguous soft tissue necrosis developed a few days after reaming. Bone and soft tissue reconstruction was subsequently performed using a circular external fixator (Ilizarov apparatus or Taylor spatial frame) a mean of four months after injury in six patients; in one case, reconstruction was undertaken four years after the original injury. Two complications (secondary tissue breakdown at a bone transport site; premature consolidation) necessitated cessation of bone transport at one of two bone transport levels in two patients. All patients eventually healed with a good functional result after an average of 11.5 months in the fixator (range, 10-13 months).

Biological rationale for the intramedullary canal as a source of autograft material

Bone harvested by intramedullary reaming offers a minimally invasive alternative to harvesting bone from the iliac crest, which has long been considered the gold standard for autogenous bone grafting. The biologic potential of intramedullary reaming material has been studied both in vitro and in vivo. The material provides osteogenic, osteoinductive, and osteoconductive properties that are comparable to the material harvested from the iliac crest. In addition to the ability to obtain a large volume of bone, the graft harvested by the Reamer-Irrigator-Aspirator has been shown to be rich in growth factors, including BMP-2, TGF-beta1, IGF-I, FGFa, and PDGFbb.

Intramedullary nailing of the femur: current concepts concerning reaming

Intramedullary fixation has advanced to the standard of care for fractures of the femoral shaft. Current controversies center on whether to prepare the intramedullary canal by reaming, particularly in certain subsets of patients. As understanding of the local and systemic effects of reaming deepens, there is a role for maximizing the benefits of intramedullary preparation before nail fixation, while attempting to minimize the major disadvantages of this technique. Several treatment strategies have emerged to address the downsides of intramedullary reaming. The purpose of this review is to discuss the history and current knowledge of intramedullary reaming with respect to problems associated with its use and the evolution of treatment modalities and their clinical applicability for orthopaedic trauma care.

Thermal necrosis complicating reamed intramedullary nailing of a closed tibial diaphysis fracture: a case report

A case report of thermal necrosis of the tibia after reamed intramedullary nailing is presented. Given the consequences of this complication, the proper use of reaming technique and equipment is emphasized.

The biological and physiological effects of intramedullary reaming

This paper summarises the current knowledge on the effects of medullary reaming of long-bone fractures. Following a review of intramedullary vascular physiology, the consequences for vascularity, the autograft effects, the generation of heat, and fat embolism are outlined. Also, alternative reaming techniques are described.

Perioperative creatine phosphokinase (CPK) and troponin I trends after elective hip surgery

BACKGROUND

Perioperative myocardial infarction (MI) is an important risk factor for cardiac morbidity and mortality after hip surgery. On the basis of the limitations of creatine kinase cardiac muscle isoenzyme (CK-MB) in the perioperative setting, and the high specificity of troponin I, we hypothesized that troponin I would be effective at detecting perioperative MI more frequently than CK-MB would be, after hip surgery.

METHODS

A prospective study of the serum levels of creatine phosphokinase (CPK), its isoenzyme CK-MB, and troponin I, in 90 patients with risk factors for coronary artery disease, undergoing hip surgery is reported. We measured these cardiac markers in the postoperative period for 5 days, after hemiarthroplasty, total hip arthroplasty, and hip intramedullary nailing.

RESULTS

We found increased levels of creatine phosphokinase and CK-MB, after all the types of operation, with maximum levels reached on the first postoperative day and the levels were more pronounced after total hip arthroplasty. False-elevated CK-MB index >6% without MI was evidenced in 43.3% of patients. Troponin I levels were elevated >3.1 ng/mL only in the patients who suffered MI postoperatively. All the patients who suffered MI had both CK-MB index and troponin I levels elevated. Also, we found high correlation between maximum CK-MB levels and size of implants, which means that reaming and its heating effect may be responsible for false-elevated CK-MB levels, except direct muscle damage caused by surgical incision.

CONCLUSION

CK-MB index and troponin I have the same sensitivity, but troponin I is more specific than CK-MB index in detecting MI after hip surgery.

Novel technique for medullary canal débridement in tibia and femur osteomyelitis

Intramedullary infection is a challenging problem and treatment usually includes removal of infected hardware and reaming of the medullary canal. We describe a new technique for canal débridement and evaluate its infection control rate in treating osteomyelitis of the tibia and femur. We retrospectively reviewed 11 patients with posttraumatic osteomyelitis of the tibia (n = 8) or femur (n = 3). Surgery included débridement, implant removal, and reaming of the medullary canal with a new device that allows reaming under simultaneous irrigation and aspiration. At a minimum followup time of 6 months (mean, 13 months; range, 6-23 months), we observed no recurrence of infection. Complications included one partial loss of a flap, one refracture of a tibia after an automobile versus pedestrian accident, and external fixator pin tract infections in one patient. These preliminary data suggest the new reaming device may be a useful adjunct for débriding intramedullary infections of the tibia and femur.

Safety evaluation of large external fixation clamps and frames in a magnetic resonance environment

Large orthopedic external fixation clamps and related components were evaluated for force, torque, and heating response when subjected to the strong electromagnetic fields of magnetic-resonance (MR) imaging devices. Forces induced by a 3-Tesla (T) MR scanner were compiled for newly designed nonmagnetic clamps and older clamps that contained ferromagnetic components. Heating trials were performed in a 1.5 and in a 3 T MR scanner with two assembled external fixation frames. Forces of the newly designed clamps were more than a factor 2 lower as the gravitational force on the device whereas, magnetic forces on the older devices showed over 10 times the force induced by earth acceleration of gravity. No torque effects could be found for the newly designed clamps. Temperature measurements at the tips of Schanz screws in the 1.5 T MR scanner showed a rise of 0.7 degrees C for a pelvic frame and of 2.1 degrees C for a diamond knee bridge frame when normalized to a specific absorption rate (SAR) of 2 W/kg. The normalized temperature increases in the 3 T MR scanner were 0.9 degrees C for the pelvic frame and 1.1 degrees C for the knee bridge frame. Large external fixation frames assembled with the newly designed clamps (390 Series Clamps), carbon fiber reinforced rods, and implant quality 316L stainless steel Schanz screws met prevailing force and torque limits when tested in a 3-T field, and demonstrated temperature increase that met IEC-60601 guidelines for extremities. The influence of frame-induced eddy currents on the risk of peripheral nerve stimulation was not investigated.

Quantitative assessment of growth factors in reaming aspirate, iliac crest, and platelet preparation

Large bony defects and non-unions are still a complication in trauma and orthopedic surgery. Treatment strategies include the use of autogenous materials (iliac crest), allogenic bone, bone substitutes, and currently stimulation with growth factors such as BMP-2, BMP-7 or the growth factors containing platelet-rich plasma (PRP). Another source of bone graft material might be the cuttings produced during intramedullary reaming. The aim of this study was to compare the quantity of various growth factors found within iliac crest, bony reaming debris, reaming irrigation fluid, and platelet-rich plasma. Iliac crest and reaming debris and irrigation samples were harvested during surgery. PRP was prepared from blood. The growth factors in the bony materials (iliac crest or reaming debris) and of the liquid materials (platelet-poor plasma (PPP), platelet-rich plasma (PRP) or reaming irrigation) were compared. Elevated levels of FGFa, PDGF, IGF-I, TGF-beta1 and BMP-2 were measured in the reaming debris as compared to iliac crest curettings. However, VEGF and FGFb were significantly lower in the reaming debris than from iliac crest samples. In comparing PRP and PPP all detectable growth factors, except IGF-I, were enhanced in the platelet-rich plasma. In the reaming irrigation FGFa (no measurable value in the PRP) and FGFb were higher, but VEGF, PDGF, IGF-I, TGF-beta1 and BMP-2 were lower compared to PRP. BMP-4 was not measurable in any sample. The bony reaming debris is a rich source of growth factors with a content comparable to that from iliac crest. The irrigation fluid from the reaming also contains growth factors.

Effects of repeated drill use on temperature of bone during preparation for osteosynthesis self-tapping screws

Drills used during preparation for osteosynthesis with self-tapping screws are often used repeatedly until they become blunt and ineffective. Because the sharpness of the drill is one of the most important factors in its cutting efficiency, blunt drills may require the application of extra force, which in turn may contribute to excessive frictional heat produced during preparation of screw holes. Large rises in temperature can impair bony regeneration around screws and contribute to failure of internal fixation. In an attempt to quantify the potential increase in temperature produced by blunt drills, we devised an in vitro experiment to simulate preparation for osteosynthesis by using drills with different degrees of wear. Three drills were used: one was new, one had drilled 600 holes, and the third drill had been in use in theatre for several months. The mean (range) rise in temperature for the three drills were: new drill 7.5 degrees C (0.6-20.5 degrees C); drill after 600 holes 13.4 degrees C (5.7-28.3 degrees C); and drill from theatre 25.4 degrees C (12.4-41.3 degrees C). There was a highly significant difference in the temperatures generated by the three drills, and the changes in temperature were related to the amount of wear. The cost of drills is low, and as their repeated use can compromise the results of the operation they must be discarded after single use.

The thermal effects of intramedullary reaming

OBJECTIVE

To study the effect of tourniquet control on intramedullary reaming.

DESIGN

An experimental prospective nonsurvival animal study was performed using 5 mongrel dogs. A pneumatic tourniquet was randomized to either the right or left hind limb. Tibial intramedullary reaming was performed with progressively larger reamers. Cortical temperatures were measured using thermocouples inserted into the tibial diaphyseal cortex. Thermocouples were connected to an analog to digital converter that output continuous data that was collected on a computer. Upon completion of the procedure, the animals were killed.

RESULTS

The peak and low temperatures for each thermocouple with each reamer passage were recorded. Reamer sizes larger than the internal diameter of the intramedullary canal produced higher peak temperatures. The mean delta t (peak temperature minus low temperature) was calculated for each reamer passage. This measurement represents the overall amount of heat generated during each reamer passage. There were no significant differences between the 2 conditions (P = 0.8, paired t test). Temperatures decreased in between reamer exchange but did not return to baseline levels.

CONCLUSIONS

Because similar temperatures were measured both with and without a tourniquet, the risk of thermal necrosis appears to be related more to the process of intramedullary reaming than to the tourniquet. Higher temperatures were measured with reamer sizes larger than the internal diameter of the intramedullary canal. Increasing the time interval between the passage of successive reamers may allow heat to dissipate and decrease the risk of thermal necrosis. The clinical practice of limited reaming ("ream-to-fit") should minimize the occurrence of this complication.

The influence of the size and condition of the reamers on bone temperature during intramedullary reaming

BACKGROUND

The objectives of this study were to determine whether intramedullary reaming increases bone temperature in vivo to a level that is high enough to produce bone necrosis and to determine the influence of the size and the condition of the reamers on the temperature increase.

METHODS

Bone temperature variations were recorded in vivo during intramedullary tibial reaming in fourteen minipigs. The left tibiae were progressively reamed from 6 to 9 mm. The right tibiae were reamed with only 8 and 9-mm reamers. The variables studied were the initial and final temperature and the increase in the temperature. Two weeks after reaming, the tibiae were removed and studied histologically.

RESULTS

Intramedullary reaming produced an average increase (and standard deviation) in bone temperature of 6.9 degrees C +/- 4.1 degrees C. The peak temperatures ranged from 34.9 degrees C to 49.4 degrees C. The average maximum bone temperature was 38.1 degrees C +/- 2.8 degrees C when the reaming was done progressively from 6 to 9 mm and 41.1 degrees C +/- 4.4 degrees C when the reaming was done only with the 8 and 9-mm reamers. The mean increase in the temperature in the second group of animals (8.2 degrees C +/- 4.3 degrees C) was greater than that in the first group (5.4 degrees C +/- 3.5 degrees C). Reaming with sharper reamers in the first seven animals resulted in a smaller mean increase in temperature than did reaming with less sharp reamers in the last seven animals (4.6 degrees C compared with 9.2 degrees C; p = 0.001). Histological examination of the tibiae showed periosteal proliferation and an altered disposition of the osteons at the inner cortex with occasional necrotic bone fragments in the medullary canal.

CONCLUSIONS

Intramedullary reaming in the minipig increased bone temperature. When the reamer initially used was larger than the diameter of the medullary canal and when the reamers were blunted by repeated use, the maximum temperature reached by the bone was higher. This increase in temperature with use of typical medullary reaming techniques did not exceed the limits that would produce bone necrosis.