Elution Profiles of Two Methods of Antibiotic Tibial Nail Preparations

Antibiotic cement nails manufactured with threaded rods or cannulated intramedullary nails are better than those made with guidewires and do not debond

Purpose

The purpose of this study was to comparatively evaluate cement debonding at the time of removal of antibiotic cemented coated nails (ABNs) with cores made with a guidewire ($120), a regular intramedullary nail ($1100) or a threaded rod from a circular frame external fixator set ($60).

Methods

A retrospective study was performed on 32 ABNs that had been implanted for long bone infections after intramedullary nailing. All ABNs were manufactured intraoperatively by the treating surgeon using 2 grams of vancomycin and single package of Tobramycin Simplex Cement (Stryker, Kalamazoo, MI). The powder, antibiotics, and polymer were mixed and then injected into an ABN cement mold (Bonesetter Holdings USA). Debonding was assessed at time of removal by the operating surgeon. Rates of cement debonding between the 3 groups were statistically compared.

Results

Debonding occurred in 0/12 of the cement nails manufactured with an intramedullary nail, 0/7 threaded rod ABNs, and 6/13 guidewire ABNs. There was a significant difference in the rate of debonding between the 3 groups (P < 0.01). Removal of the remnant cement was accomplished with thin osteotomes, long pituitary rongeurs, or reamers. The canal was visualized using an arthroscope to ensure complete removal of the cement.

Conclusion

ABNs fabricated with standard intramedullary nails or threaded rods did not lead to any debonding. Debonding of the cement from the inner core of an antibiotic nail often requires significant effort to remove the remnant cement. Given that threaded rods are often cheaper than guidewires, we recommend that ABNs be fabricated with either threaded rods or interlocking nails, but not guidewires, depending on the level of stability required.

Antibiotic cement-coated rigid locked nails in infected femoral and tibial nonunion. Reoperation rates of commercial versus custom-made nails

INTRODUCTION

The objective of this study is to assess bone union, infection control, and reoperation rates in a series of patients with infected femoral or tibial nonunion treated with antibiotic-cement-coated rigid nails and to compare the results obtained with custom-made nails versus commercial nails.

METHODS

We retrospectively analyzed a series of consecutive patients with infected nonunion of the femur or the tibia treated with antibiotic-cement-coated rigid nails between January 2010 and 2020. We assessed patients' distinctive characteristics, initial injury, type of nail used (custom-made nail with vancomycin or commercial nail with gentamicin), success rate (bone union + infection control), reoperation rate, and failure rate. Comparative analyses were conducted between reoperated and non-reoperated patients regarding the type of nail used. A multivariate regression analysis was performed to assess the risk variables that impacted reoperation rates.

RESULTS

We included 54 patients with 22 (40.74%) infected femoral nonunions and 32 (59.25%) tibial nonunions, who were treated with 38 (70.37%) custom-made antibiotic-cement coated nails and 16 (29.62%) commercial nails. Bone union and infection control were achieved in 51 (94.44%) cases. The reoperation rate was 40.74% (n = 22), and the failure rate was 5.55% (n = 3). The use of custom-made nails was associated with a higher risk of reoperation (Odds Ratio 4.71; 95% Confidence Interval 1.10 - 20.17; p = 0.036).

CONCLUSION

Antibiotic-cement-coated nails reached a 94.44% success rate. Nails manufactured in the OR coated with vancomycin cement were associated with a higher risk of reoperation than commercial nails loaded with gentamicin cement.

LEVEL OF EVIDENCE

III comparative, observational, non-randomized.

Antibiotic Cement-Coated Interlocked Intramedullary Nails for the Treatment of Infected Nonunion After Intramedullary Nailing

OBJECTIVE

To evaluate outcomes using an interlocking antibiotic cement-coated nail and culture-specific systematic antibiotics in the treatment of infected nonunion after intramedullary nailing.

DESIGN

Retrospective observational cohort study.

SETTING

Urban level I trauma center.

PATIENTS/PARTICIPANTS

Forty-one nonconsecutive patients who presented to a level I trauma center who underwent interlocked antibiotic nailing for treatment of infected nonunion status after primary intramedullary nailing.

OUTCOMES

Eradication of infection, radiographic union by 2-year follow-up.

RESULTS

Antibiotic nailing successfully eradicated infection and led to fracture healing in 35 patients (85.4%), while 6 patients (14.6%) had persistent infection and required further surgical treatment. Of the 6 patients who required further treatment, 5 eventually went on to heal with fracture union and eradication of their infection, while 1 required a salvage procedure. Of the 5 patients who eventually went on to heal, 4 of them healed with repeat antibiotic or intramedullary nails, while 1 required segmental resection and bone grafting before healing.

CONCLUSIONS

This study suggests that the proposed interlocked antibiotic nailing technique is a viable therapeutic option to eradicate infected nonunion and support fracture healing.

LEVEL OF EVIDENCE

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

Efficacy of Infection Eradication in Antibiotic Cement-Coated Intramedullary Nails for Fracture-Related Infections, Nonunions, and Fusions

Antibiotic cement-coated intramedullary nails (ACCINs) are increasing in popularity as a viable solution for the treatment of fracture-related infections (FRIs), infected long bone nonunions, and arthrodeses without an external fixator. ACCINs effectively manage to fulfill three of the basic principles for eradicating osteomyelitis: dead space management, antibiotic delivery, and bone stability. We performed a retrospective review of 111 patients who were treated with ACCINs between January 2014 and December 2020. In our series, 87.4% (n = 97) of patients achieved healed and uninfected bone or stable arthrodesis at a mean follow-up of 29.2 months (range, 6–93 months). Additionally, 69.1% (n = 67) of healed patients were resolved after only one procedure, and the remainder (30.9%, n = 30) healed after one or more additional procedures. The mean number of additional procedures was 2.1 (range, 1–6 additional procedures). The overall limb salvage rate was 93.7% (n = 104). The majority of the total cohort were successfully treated in only one surgery. This study suggests that ACCINs are effective in the treatment of FRIs, infected long bone nonunions, and infected ankle and knee arthrodeses.

Tobramycin Blood Levels after Local Antibiotic Treatment of Bone and Soft Tissue Infection

Local antibiotic delivery using different carriers plays an important role in both infection prophylaxis and treatment. Besides dead space management, these carriers have the advantage of providing a high concentration of local antibiotics with a lower risk of systemic toxicity. Few studies have reported on systemic toxicity associated with antibiotic-impregnated carriers. The present study investigates the systemic tobramycin concentration at 24, 48 and 72 h postoperatively after using tobramycin-loaded polymethyl methacrylate (PMMA) and calcium sulfate (CS) as local antibiotic carriers. Additionally, this work assesses the renal function postoperatively for indications of acute kidney injury (AKI). Fifty-two patients were treated in 58 procedures with tobramycin and vancomycin-loaded PMMA, CS, or both. All systemic tobramycin levels were <2 mcg/mL at 72 h, and the resulting rate of AKI was 12% (7/58). In conclusion, local tobramycin antibiotic delivery using PMMA, CS, or both remains a safe and effective modality in the treatment of osteomyelitis as long as the surgeon is aware of its possible nephrotoxic effect.

Outcomes of Various Antibiotic Cement-Coated Intramedullary Implants on the Treatment of Long Bone Septic Nonunion

OBJECTIVE

To determine the effectiveness of various types of antibiotic-coated intramedullary implants in the treatment of septic long bone nonunion.

DESIGN

Retrospective chart review.

SETTING

Level 1 trauma center.

PARTICIPANTS

Forty-one patients with septic long bone nonunion treated with an antibiotic cement-coated intramedullary implant.

INTERVENTION

Surgical debridement and placement of a type of antibiotic-coated intramedullary implant.

MAIN OUTCOME MEASUREMENTS

Union and need for reoperation.

RESULTS

At an average 27-month follow-up (6-104), 27 patients (66%) had a modified radiographic union score of the tibia of 11.5 or greater, 12 patients (29%) a score lower than 11.5, and 2 patients (5%) underwent subsequent amputation. Six patients underwent no further surgical procedures after the index operation. Patients treated with a rigid, locked antibiotic nail achieved earlier weight-bearing (P = 0.001), less frequently required autograft (P = 0.005), and underwent fewer subsequent procedures (average 0.38 vs. 3.60, P = 0.004) than those treated with flexible core antibiotic rods.

CONCLUSIONS

Antibiotic-coated intramedullary implants are successful in the treatment of septic nonunions in long bones. In our cohort, rigid, statically locked nails allowed faster rehabilitation, decreased the need for autograft, and decreased the number of additional surgical procedures. Further study is needed to confirm these findings.

LEVEL OF EVIDENCE

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

Antibiotic cement coating in orthopedic surgery: a systematic review of reported clinical techniques

Background

Antibiotic-containing cement and bone graft substitute-coated orthopedic implants provide the advantages of simultaneous local antibiotic delivery and internal stable fixation, aiding in both infection eradication and osseous healing. Standardized protocols pertaining to implant coating techniques in various clinical and particularly intraoperative settings are scarce, and available literature is limited. This systematic review aims to provide a summary of the available current literature reporting on custom-made coating techniques of orthopedic implants, indications, outcomes, and associated complications in clinical use.

Methods

A systematic search of the literature in PubMed, Medline, Embase, and Cochrane Library databases was performed in accordance with PRISMA guidelines. Articles reporting specifically on custom-made coating techniques of orthopedic implants in a clinical setting were eligible.

Results

A total of 41 articles with a cumulative total number of 607 cases were included. Indications for treatment mostly involved intramedullary infections after previous plate osteosynthesis or nailing. A variety of implants ranging from intramedullary nails, plates, wires, and rods served as metal cores for coating. Polymethylmethacrylate (PMMA) bone cement was most commonly used, with vancomycin as the most frequently added antibiotic additive. Chest tubes and silicone tubes were most often used to mold. Common complications are cement debonding and breakage of the metallic implant.

Conclusion

Adequate coating techniques can reduce the burden of treatment and be associated with favorable outcomes. Lack of general consensus and heterogeneity in the reported literature indicate that the perfect all-in-one implant coating method is yet to be found. Further efforts to improve implant coating techniques are warranted.

Level of evidence

III.

Single-Stage Treatment of Fracture-related Infections

Fracture-related infections (FRIs) remain a significant problem. Many approach FRI cases in a staged fashion, focusing on infection eradication initially and fracture union during subsequent procedures. The literature quotes high success rates with this strategy. However, associated patient morbidity and economic impact are noteworthy. A single-stage FRI treatment, using an antibiotic-coated locked intramedullary nail, also exists. This video details low-cost, antibiotic-coated locked intramedullary nail fabrication in the operating room alongside preliminary results using this technique for acute FRI and septic nonunion treatment.

Coated nails: is their use supported by the literature?

Antibiotic-coated intramedullary nails have been popularized in recent decades for treating long-bone infections. They are especially useful in treating diaphyseal infections requiring stability, such as those involving fractures and nonunions. The nails are made by injecting antibiotic-impregnated polymethylmethacrylate or "cement" around a metal core using a silicone tube as a mold. There are a variety of techniques that can be used to customize the nail to the affected site. Antibiotic cement has long been demonstrated as an effective local antibiotic delivery system. It is able to elute high concentrations of antibiotics while having little systemic toxicity. Several case series have reported good outcomes using this technique, defined by bone union and infection control. Further research is needed to determine the amount of weight that can safely be transferred through the nail and to optimize antibiotic elution.

Does coating an intramedullary nail with polymethylmethacrylate improve mechanical stability at the fracture site?

BACKGROUND

Treatment of tibia diaphyseal fractures with intramedullary nail fixation has proven to be effective. An increasingly popular practice is to coat the nail with bone cement incorporating antibiotics for the purpose of treating and/or preventing infection. To date, the effect of coating on the mechanical performance of the intramedullary nail once implanted is unknown. We hypothesize that cement coating does not change the cross-sectional stiffness of the nail, so that, when fixing tibia diaphyseal fracture with gapping, cement coated intramedullary nail provide stiffness comparable to that of standard conventional uncoated ones.

METHODS

Tests of 4-point bending were conducted to compare the cross-sectional stiffness of uncoated to coated nails. In addition, mechanical tests of compression and torsion on tibia bone phantoms instrumented with coated and uncoated nails were performed, and the proximal-to-distal bone fragment rotations were compared.

FINDINGS

The 4-point bending tests indicated that the cross-sectional stiffness of coated nails was not significantly different from that of the uncoated ones (p-value >0.05). Mechanical tests of compression and torsion corroborated these results by showing no statistical difference in the proximal-to-distal bone rotations attained with uncoated nails when compared to those measured for the coated ones (p-value >0.05).

INTERPRETATION

Cement coating on the nail cannot be relied upon for increased mechanical stiffness of the implant, and should be solely considered as a vehicle for topic delivery of antibiotics.

A distinctive release profile of vancomycin and tobramycin from a new and injectable polymeric dicalcium phosphate dehydrate cement (P-DCPD)

A novel injectable polymeric dicalcium phosphate dehydrate (P-DCPD) cement was developed with superior mechanical strength and excellent cohesion. The purpose of this study was to assess the in vitro performance of P-DCPD loaded with vancomycin (VAN-P), tobramycin (TOB-P) and combination of both (VAN/TOB-P) (10%, w/w). There is a distinctive release profile between VAN and TOB. VAN-P showed decreased initial burst (<30% within 3 d) and sustained VAN release (76% in 28 d). In the presence of TOB (VAN/TOB-P), >90% of VAN was released within 3 d (p < 0.05). Slow and limited TOB release was observed both in TOB-P (<5%) and in TOB/VAN-P (<1%) over 28 d. Zone of inhibition (ZOI) of Staphylococcus aureus growth showed that eluents collected from VAN-P had stronger and longer ZOI (28 d) than that from TOB-P (14 d, p < 0.05). Direct contact of VAN-P, TOB-P and VAN/TOB-P cements displayed persistent and strong ZOI for >3 weeks. Interestingly, the cement residues (28 d after drug release) still maintained strong ZOI ability. P-DCPD with or without antibiotics loading were nontoxic and had no inferior impacts on the growth of osteoblastic MC3T3 cells. VAN-P and TOB-P were injectable. No significant influence on setting time was observed in both VAN-P (11.7 ± 1.9 min) and VAN/TOB-P (10.8 ± 1.5 min) as compared to control (12.2 ± 2.6 min). We propose that a distinctive release profile of VAN and TOB observed is mainly due to different distribution pattern of VAN and TOB within P-DCPD matrix. A limited release of TOB might be due to the incorporation of TOB inside the crystalline lattice of P-DCPD crystals. Our data supported that the bactericidal efficacy of antibiotics-loaded P-DCPD is not only depend on the amount and velocity of antibiotics released, but also probably more on the direct contact of attached bacteria on the degrading cement surface.

Release characteristics of enoxaparin sodium-loaded polymethylmethacrylate bone cement

BACKGROUND

This study aimed to prepare the polymethylmethacrylate (PMMA) bone cement release system with different concentrations of enoxaparin sodium (ES) and to investigate the release characteristics of ES after loading into the PMMA bone cement.

METHODS

In the experimental group, 40 g Palacos®R PMMA bone cement was loaded with various amount of ES 4000, 8000, 12,000, 16,000, 20,000, and 24,000 AXaIU, respectively. The control group was not loaded with ES. Scanning electron microscopy (SEM) was used to observe the surface microstructure of the bone cement in the two groups. In the experiment group, the mold was extracted continuously with pH7.4 Tris-HCL buffer for 10 days. The extract solution was collected every day and the anti-FXa potency was measured. The experiment design and statistical analysis were conducted using a quantitative response parallel line method.

RESULTS

Under the SEM, it was observed that ES was filled in the pores of PMMA bone cement polymer structure and released from the pores after extraction. There was a burst effect of the release. The release amount of ES on the first day was 0.415, 0.858, 1.110, 1.564, 1.952, and 2.513, respectively, from the six groups with various ES loading amount of 4000, 8000, 12,000, 16,000, 20,000, and 24,000 AXaIU, all reaching the peak of release on the first day. The release decreased rapidly on the next day and entered the plateau phase on the fourth day.

CONCLUSION

The prepared ES-PMMA bone cement has high application potential in orthopedic surgery. ES-PMMA bone cement shows good drug release characteristics. The released enoxaparin sodium has a local anti-coagulant effect within 24 h after application, but it will not be released for a long time, which is complementary to postoperative anti-coagulation therapy.

Musculoskeletal Infection in Orthopaedic Trauma: Assessment of the 2018 International Consensus Meeting on Musculoskeletal Infection

Fracture-related infections (FRIs) are among the most common complications following fracture fixation, and they have a huge economic and functional impact on patients. Because consensus guidelines with respect to prevention, diagnosis, and treatment of this major complication are scarce, delegates from different countries gathered in Philadelphia in July 2018 as part of the Second International Consensus Meeting (ICM) on Musculoskeletal Infection. This paper summarizes the discussion and recommendations from that consensus meeting, using the Delphi technique, with a focus on FRIs. A standardized definition that was based on diagnostic criteria was endorsed, which will hopefully improve reporting and research on FRIs in the future. Furthermore, this paper provides a grade of evidence (strong, moderate, limited, or consensus) for strategies and practices that prevent and treat infection. The grade of evidence is based on the quality of evidence as utilized by the American Academy of Orthopaedic Surgeons. The guidelines presented herein focus not only on the appropriate use of antibiotics, but also on practices for the timing of fracture fixation, soft-tissue coverage, and bone defect and hardware management. We hope that this summary as well as the full document by the International Consensus Group are utilized by those who are charged with musculoskeletal care internationally to optimize their management strategies for the prevention and treatment of FRIs.

Commercially available antibiotic-laden PMMA-covered locking nails for the treatment of fracture-related infections - A retrospective case analysis of 10 cases

Introduction: Fracture-related infections (FRIs) are a devastating complication. FRIs are challenging and should be addressed with a multidisciplinary approach. An FRI should be addressed surgically by non-viable bone debridement, local antibiotic deposition, minimization of dead space and fracture stabilization. Antibiotic-laden PMMA-covered nails are a viable option to face these complications. To demonstrate the safety and utility of commercially available antibiotic-laden PMMA-covered nails, we performed a review of the cases operated in our institution and a cost analysis to compare the cost of a commercial nail to other available alternatives.

Material and methods: We designed a retrospective study of consecutive cases to demonstrate the safety and efficacy of antibiotic-laden PMMA-covered commercial nails and designed a cost analysis of commercial coated nails compared to other custom-made alternatives.

Results: We treated seven tibias and three femurs. Nine patients fully fit the criteria for FRI. There was one case of reintervention because of persistent drainage. All fractures healed, and in the first year post-intervention, there were no signs or symptoms of infection. There were no complications related to the commercially available nail that was used. There is a small increase in the direct quantifiable cost in commercially available nails, but non-quantifiable cost should be assessed individually.

Conclusions: Commercially available antibiotic-laden PMMA-covered nails are a safe and useful treatment option for complicated cases of lower limb long bone reconstruction. The low complication rate and the straightforward technique compensate for the direct cost increase in most situations.