Septic arthritis in ACL reconstruction surgery with hamstring autografts. Eleven years of experience

Incidence, Common Pathogens, and Risk Factors for Infection after Primary Anterior Cruciate Ligament Reconstruction: A Systematic Review

We sought to assess the current literature to present a comprehensive summary of the incidence, common pathogens, and risk factors for infection after anterior cruciate ligament (ACL) reconstruction. PubMed, CINAHL, EMBASE, and Scopus databases were searched for relevant studies reporting on infection after ACL reconstruction. Two reviewers independently screened the extracted studies for adherence to inclusion and exclusion criteria. Studies were selected if they reported on the incidence of infection, pathogens cultured from infected knees, or risk factors for infection after primary ACL reconstruction. Exclusion criteria consisted of studies with fewer than 100 patients or studies that included revision ACL reconstruction. Fifty studies met the inclusion and exclusion criteria, reporting on a total of 316,214 ACL reconstructions. Included studies evaluated between 123 and 104,255 patients. The overall incidence of infection was 0.60% (0.15-2.44%). The most common pathogens were Staphylococcus aureus, S. epidermidis, and coagulase-negative Staphylococci. Five studies reported that the use of hamstring autograft was a statistically significant risk factor for infection after ACL reconstruction, thus making hamstring autograft the most commonly reported risk factor. Other reported risk factors included male sex, use of immuno-suppressive medications or intraarticular steroid injections, prior knee surgery, and diabetes. Systematic review of the literature revealed that infection after ACL reconstruction remains an infrequent event with an incidence of 0.60% (0.15-2.44%). Furthermore, the most common pathogens are from the Staphylococcus genus of bacteria, comprising 84% of all culture-positive infections. Multiple risk factors have been reported for ACL reconstruction; however, statistical significance varied across studies. Together, these findings may help guide physicians in the prevention and treatment of infection after ACL reconstruction.

Optimising the Early-Stage Rehabilitation Process Post-ACL Reconstruction

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and a high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high-quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction, which limits knee function and the ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming, and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g. mid-stage rehabilitation entry criteria).

ESSKA and EBJIS recommendations for the management of infections after anterior cruciate ligament reconstruction (ACL-R): prevention, surgical treatment and rehabilitation

PURPOSE

Infection after anterior cruciate ligament reconstruction (ACL-R) is a rare but severe complication. Despite an increase in articles published on this topic over the last decade, solid data to optimized diagnostic and therapeutic measures are scarce. For this reason, the European Bone and Joint Infection Society (EBJIS) and the European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) collaborated in order to develop recommendations for the diagnosis and management of infections after ACL-R. The aim of the workgroup was to perform a review of the literature and provide practical guidance to healthcare professionals involved in the management of infections after ACL-R.

METHODS

An international workgroup was recruited to provide recommendations for predefined clinical dilemmas regarding the management of infections after ACL-R. MEDLINE, EMBASE, Cochrane Library and Scopus databases were searched for evidence to support the recommended answers to each dilemma.

RESULTS

The recommendations were divided into two articles. The first covers etiology, prevention, diagnosis and antimicrobial treatment of septic arthritis following ACL-R and is primarily aimed at infectious disease specialists. This article includes the second part of the recommendations and covers prevention of infections after ACL-R, surgical treatment of septic arthritis following ACL-R and subsequent postoperative rehabilitation. It is aimed not only at orthopedic surgeons, but at all healthcare professionals dealing with patients suffering from infections after ACL-R.

CONCLUSION

These recommendations guide clinicians in achieving timely and accurate diagnosis as well as providing optimal management, both of which are paramount to prevent loss of function and other devastating sequelae of infection in the knee joint.

LEVEL OF EVIDENCE

V.

The early infection characterization of septic arthritis by Staphylococcus aureus after anterior cruciate ligament reconstruction in a novel rat model

BACKGROUND

The present study aimed to explore the time of maximum bacterial load and main colonization knee site in bacterial infection process based on a novel rat model of septic arthritis (SA) after anterior cruciate ligament reconstruction (ACLR).

METHODS

Ninety-five Wistar rats with unilateral ACLR, random enrolled into control surgery (CS) group; joint inject (JI) group; presoaking (PS) group, were injected with 30 μl sterile saline or 30 μl × 10⁷ colony forming units/ml Staphylococcus aureus via the knee joint or graft with presoaked Staphylococcus aureus during ACLR, respectively. At 1, 4, 7, 11, and 14 days postoperatively, samples were harvested to evaluate progress of knee joint infection by postoperative body weight, body temperature, knee temperature, knee width, scales of tissue damage, serum inflammatory markers, microbiological counting, microcomputed tomography (Micro-CT), digital radiography, magnetic resonance imaging (MRI) examination, and scanning electron microscopy (SEM).

RESULTS

No systemic infection was observed in all rats. Comparing with serum inflammatory markers, tissue scores of inflammatory reactions, bacterial counts in the CS group, these data were significantly elevated in the JI group and PS group. The bone mass around the bone tunnel was lower and the soft tissue of knee showed more obvious swelling on MRI in the infection groups than that in the CS group at 7 and 14 days postoperatively. Staphylococcus aureus clusters on the surface of screw and graft were observed in the infection group. The whole colony forming units of Staphylococcus aureus maintained a continuous upward trend peaking 7 and 11 days followed by a balanced curve in the infection groups. Bone and soft tissue were found to have more bacterial counts than graft and screws.

CONCLUSION

This animal model effectively mimics the acute knee infection after ACLR. We found that the bacterial colonization exhibited the peak of acute infection between 7 and 11 days postoperatively, with the major bacteria loads found in the bone, soft tissue.

Wrap It! Preventive Antimicrobial Treatment Shows No Negative Effects on Tenocytes and Tendons-A Comprehensive Approach

Although the rate of infection after the reconstruction of a ruptured anterior cruciate ligament (ACL) is low, prophylactic incubation of the graft with vancomycin (Vanco-wrap or vancomycin soaking) is routinely performed. A cytotoxic effect of vancomycin is reported for several cell types, and the prophylactic treatment might prevent infection but harm the tissue and cells.

AIM

A comprehensive study was performed to investigate the effect of vancomycin on tendon tissue and isolated tenocytes using cell viability, molecular and mechanical analysis.

MATERIAL AND METHODS

Rat tendons or isolated tenocytes were incubated in increasing concentrations of vancomycin (0-10 mg/mL) for different times, and cell viability, gene expression, histology and Young's modulus were analyzed.

RESULTS

The clinically used concentration of vancomycin (5 mg/mL for 20 min) had no negative effect on cell viability in the tendons or the isolated tenocytes, while incubation with the toxic control significantly reduced cell viability. Increasing the concentration and prolonging the incubation time had no negative effect on the cells. The expression of Col1a1, Col3a1 and the tenocyte markers mohawk, scleraxis and tenomodulin was not affected by the various vancomycin concentrations. The structural integrity as measured through histological and mechanical testing was not compromised.

CONCLUSION

The results proved the safe application of the Vanco-wrap on tendon tissue.

LEVEL OF EVIDENCE

IV.

Postoperative Infection after Anterior Cruciate Ligament Reconstruction: Prevention and Management

Infection following anterior cruciate ligament (ACL) reconstruction can be one of the most debilitating complications following ACL reconstruction. Its reported incidence is around 1%. Utilization of vancomycin for presoaking the graft is considered an established method for infection prevention. The role of other agents, such as gentamycin needs further investigation. Staphylococci are the predominant causative pathogens, while particular attention should be paid to fungal infections due to their long-standing, occult process. Recent data demonstrate that hamstrings autograft may be at an elevated risk of being contaminated leading to subsequent septic arthritis. Diagnosis is set by clinical and laboratory findings and is usually confirmed by intraoperative cultures. Treatment varies, mainly depending on the intraoperative assessment. Satisfactory outcomes have been reported with both graft retaining and removal, and the decision is made upon the arthroscopic appearance of the graft and the characteristics of the infection. Of note, early management seems to lead to superior results, while persistent infection should be managed with graft removal in an attempt to protect the articular cartilage and the knee function.

Postoperative Infection: Prevention, Diagnosis, and Treatment Guidelines for the Sports Surgeon

Postoperative infection remains a potentially devastating complication facing the sports medicine surgeon. Infection prevention begins with a thorough history and physical examination to identify patient specific risk factors and aid in risk stratification. Perioperative steroid injections should be used cautiously, with increased time prior to or following surgery being associated with lower infection risk. Sterile preparation with an alcohol containing solution is typically preferred, though there is limited evidence to identify which product is superior. Diagnosis can be challenging with a high index of suspicion needed to identify and appropriately manage patients. Treatment involves prompt irrigation and debridement with deep cultures. Antibiotic coverage should begin with empiric broad treatment and be tailored based on culture results. Early consultation with an infectious disease specialist is recommended to ensure appropriate antibiotic coverage and duration of treatment.

Patients return to sports and to work after successful treatment of septic arthritis following anterior cruciate ligament reconstruction

PURPOSE

To determine specific return to sports (RTS) and return to work (RTW) rates of patients with septic arthritis following anterior cruciate ligament reconstruction (ACLR), and to assess for factors associated with a diminished postoperative return to physical activity after successful eradication of the infection.

METHODS

In this study, patients who were treated for postoperative septic arthritis of the knee following anterior cruciate ligament reconstruction between 2006 and 2018 were evaluated at a minimum follow-up (FU) of 2 years. Patients' outcomes were retrospectively analyzed using standardized patient-reported outcome scores including the Lysholm score and the subjective IKDC score, as well as return to sports and return to work questionnaires to assess for the types, number, and frequency of sports performed pre- and postoperatively and to evaluate for potential occupational changes due to septic arthritis following ACLR. To assess for the signifiance of the graft at follow-up, outcomes were compared between patients with a functioning graft at FU and those without, as well as between patients with initial graft retention and those with graft removal and consecutive revision ACLR.

RESULTS

Out of 44 patients eligible for inclusion, 38 (86%) patients at a mean age of 36.2 ± 10.3 years were enrolled in this study. At a mean follow-up of 60.3 ± 39.9 months, the Lysholm score and the subjective IKDC score reached 80.0 ± 15.1 and 78.2 ± 16.6 points, respectively. The presence of a graft at FU yielded statistically superior results only on the IKDC score (p = 0.014). There were no statistically significant differences on the Lysholm score (n.s.) or on the IKDC score (n.s.) between patients with initial graft retention and those with initial removal who had undergone revision ACLR. All of the included 38 patients were able to return to sports at a median time of 8 (6-16) months after their last surgical intervention. Among patients who performed pivoting sports prior to their injury, 23 (62.2%) returned to at least one pivoting sport postoperatively. Overall, ten patients (26.3%) returned to all their previous sports at their previous frequency. The presence of a graft at FU resulted in a significantly higher RTS rate (p = 0.010). Comparing patients with initial graft retention and those with graft removal and consecutive revision ACLR, there was no statistically significant difference concerning the RTS rate (n.s.). Thirty-one patients (83.8%) were able to return to their previous work.

CONCLUSION

Successful eradication of septic arthritis following anterior cruciate ligament reconstruction allows for a postoperative return to sports and a return to work particularly among patients with ACL-sufficient knees. However, the patients' expectations should be managed carefully, as overall return rates at the pre-injury frequency are relatively low.

LEVEL OF EVIDENCE

IV.

[Management algorithm for septic arthritis after anterior cruciate ligament reconstruction]

OBJECTIVE

To summarize the experience in the diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction.

METHODS

A retrospective review was conducted of all the arthroscopic anterior cruciate ligament reconstructions performed at Department of Sports Medicine, Peking University Third Hospital between January 2001 and December 2020. In the study, 65 of 27 867 patients experienced postoperative septic arthritis. The incidence, presentation, laboratory results, treatment, and outcome of all the infected patients were analyzed. The experiences of diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction were summarized.

RESULTS

A total of 27 867 anterior cruciate ligament reconstructions were performed at our department between January 2001 and December 2020. In the study, 65 (0.23%) patients were identified with postoperative septic arthritis. The most common symptoms of the infected patients were fever (38.7±0.5) ℃, knee swelling, pain, and restricted motion. The mean peripheral white blood cell count (WBC) was (9.2±2.6)×10⁹/L (range 4.2×10⁹/L-19.4×10⁹/L), with (72.5±6.3) % (range 54.9%-85.1%) polymorphonuclear neutrophils (N). The mean erythrocyte sedimentation rate (ESR) was (59.9±24.1) mm/h (range 9-108 mm/h), C-reactive protein (CRP) was (10.9±5.7) mg/dL (range 1.2-30.8 mg/dL), and fibrinogen (FIB) level was (7.0±1.6) g/L (range 3.7-10.8 g/L). All of the laboratory results were statistically higher in the infection group compared with the normal postoperative group (P＜0.001). The synovial white blood cell count (SWBC) of aspirated knee joint fluid was (45.0±29.8)×10⁹/L (range 7.1×10⁹-76.5×10⁹/L). Polymorphonuclear cell percentage (PMNC) was (90.27±7.86) % (range 60%-97%). In the study, 45 patients (69.2%) had positive aspirate cultures. Microbiology showed coagulase-negative Staphylococcus (CNS) and Staphylococcus aureus (SA) were the most common bacterium (34 cases and 7 cases, individually). There were 26 methicillin-resistant Staphylococcus. Both conservative (16 patients) and operative (49 patients) treatments were effective, but conservative group had a longer recovery time (5.6 d vs. 1.6 d, P=0.042).

CONCLUSION

Septic arthritis after arthroscopic anterior cruciate ligament reconstruction is a rare but potentially devastating complication. The correct diagnosis relies on synovial fluid analysis and bacterial culture. Our proposed treatment protocol is arthroscopic debridement and antibiotic therapy as quickly as possible.

Does Vancomycin Wrapping in Anterior Cruciate Ligament Reconstruction Affect Tenocyte Activity In Vitro?

Knee septic arthritis is a devastating complication following anterior cruciate ligament (ACL) reconstruction. To prevent this issue, intraoperative soaking of ACL grafts with vancomycin is often performed before implantation. Although vancomycin cytotoxicity has been reported several times, little is known about its biological effect on tenocytes. The aim of this study was to evaluate the in vitro effects of vancomycin on human primary tenocytes (hTCs). hTCs were isolated from hamstring grafts of four patients undergoing ACL reconstruction. After expansion, hTCs were treated with different concentrations of vancomycin (0, 2.5, 5, 10, 25, 50 and 100 mg/mL) for 10, 15, 30 and 60 min. In vitro cytotoxicity was evaluated measuring metabolic activity, cell toxicity, and apoptosis. hTC metabolic activity was affected starting from 10 mg/mL vancomycin and decreased markedly at 100 mg/mL. Cell viability remained unaffected only at a concentration of 2.5 mg/mL vancomycin. Vancomycin cytotoxicity was detected from 10 mg/mL after 15 min and at all higher concentrations. Cells died when treated with concentrations higher than 5 mg/mL. The use of this antibiotic on tendons to prevent infections could be useful and safe for resident cells if used at a concentration of 2.5 mg/mL for up to 1 h of treatment.

Editorial Commentary: Vancomycin Soaking of the Graft in Anterior Cruciate Ligament Reconstruction: A Concept on the Way to Becoming the New Gold Standard

An increasing number of surgeons adopt the concept of vancomycin soaking of the graft in anterior cruciate ligament reconstruction and report drastically reduced numbers of postoperative septic knee arthritis. This reduction of incidence is supported by in vitro data, showing no influence of vancomycin on tendon material properties. Although the applied antibiotic concentration has reported to be potent in eradicating graft contamination, no evidence of chondrotoxicity has been shown. Based on the increasing evidence, the call for randomized controlled trials stands in ethical contrast with the medical responsibility not to withhold patients an infection prophylaxis that has already been proven to be safe and effective.

Vancomycin-soaking of the graft reduces the incidence of septic arthritis following ACL reconstruction: results of a systematic review and meta-analysis

PURPOSE

(1) To compare the incidence of post-operative septic arthritis following anterior cruciate ligament reconstruction (ACLR) between patients receiving routine pre-operative intravenous (IV) prophylaxis only intravenous (IV) infection prophylaxis and patients receiving additional graft-soaking in a vancomycin solution (5 mg/ml) perioperatively. (2) To review the literature regarding effects of graft-soaking in vancomycin solutions on outcomes, complication rates and tendon properties in ACLR.

METHODS

To identify studies pertaining to routine pre-operative IV prophylaxis and additional usage of intra-operative vancomycin-soaked grafts in primary ACLR, the Cochrane Library, SCOPUS and MEDLINE were searched till June 2018 for English and German language studies of all levels of evidence following the PRISMA guidelines. Additionally, all accepted abstracts at the ESSKA 2018, ISAKOS 2017, AGA 2017 and AOSSM 2017 meetings were screened. Data regarding the incidence of septic arthritis were abstracted and combined in a meta-analysis. Data including outcome scores, complication rates and in vitro analyses of tendon properties were collected and summarized descriptively.

RESULTS

Upon screening 785 titles, 8 studies were included. These studies examined 5,075 patients following ACLR and followed from 6 to 52 weeks post-operatively. Of those 2099 patients in the routine pre-operative IV prophylaxis group, 44 (2.1%) cases of early septic arthritis were reported. In contrast, there were no reports of septic arthritis following ACLR in 2976 cases of vancomycin-soaked grafts. The meta-analysis yielded an odds ratio of 0.04 (0.01-0.16) favouring the addition of intra-operative vancomycin-soaking of grafts. Across all available studies, no differences in clinical outcome (i.e. incidence of ACL revision, IKDC score, Tegner score), biomechanical tendon properties, or cartilage integrity between patients with and without vancomycin-soaked grafts were identified.

CONCLUSION

The incidence of septic arthritis following ACLR can be reduced dramatically by vancomycin-soaking the grafts intra-operatively prior to graft passage and fixation. Within the limitation confines of this study, intra-operative graft-soaking in vancomycin appears to be a safe and effective method to reduce the incidence of septic arthritis following ACLR. Still, it remains debatable if the available data facilitate the recommendation for a universal application of vancomycin-soaking for all ACLR patients or if it should be reserved for patients at risk, including the use hamstring tendons, revision cases and in the presence of medical preconditions.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and Level IV studies.

Screw and Sheath Tibial Fixation Associated With a Higher Likelihood of Deep Infection After Hamstring Graft Anterior Cruciate Ligament Reconstruction

BACKGROUND

Hamstring autograft anterior cruciate ligament reconstructions (ACLRs) have exhibited higher infection rates compared with bone-patellar tendon-bone (BPTB) autograft. The reason for this observed difference is unclear, warranting investigation.

PURPOSE

To evaluate the association between tibial fixation, either with or without a sheath and screw construct, and the risk of deep infection after hamstring autograft ACLR, using BPTB autograft as a reference group for comparison.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Using the Kaiser Permanente ACLR Registry, we identified all primary isolated, unilateral, single-bundle ACLRs with a BPTB or hamstring autograft (January 1, 2008, to September 30, 2016). The exposure groups included the following: (1) BPTB ACLR, (2) hamstring ACLR using a screw and sheath construct for tibial fixation (HS with screw and sheath), and (3) hamstring ACLR using a method other than a screw and sheath construct for tibial fixation (HS without screw and sheath). We used logistic regression to evaluate the likelihood of 90-day postoperative deep infection using BPTB autograft as the reference group and adjusting for age, sex, and body mass index. The number needed to be exposed (NNE) was calculated.

RESULTS

Of 15,671 ACLRs, 6745 (43.0%) used a BPTB graft, 2852 (18.2%) used HS with screw and sheath tibial fixation, and 6074 (38.8%) used HS without screw and sheath tibial fixation. There were 38 (0.2%) 90-day deep infections: 11 (0.2%) for BPTB, 14 (0.5%) for HS with screw and sheath, and 13 (0.2%) for HS without screw and sheath. Staphylococcus aureus for the BPTB group and Staphylococcus epidermidis in both hamstring groups were the most common infecting organisms. HS with screw and sheath had a higher likelihood of 90-day deep infection compared with BPTB ACLR (odds ratio [OR], 2.87; 95% CI, 1.29-6.38). We failed to observe a difference for HS without screw and sheath compared with BPTB ACLR (OR, 1.23; 95% CI, 0.54-2.77). The NNE was 330 and 2701 for HS with and HS without screw and sheath, respectively.

CONCLUSION

Although the overall infection rate after ACLR is low, the higher likelihood of infections when sheath and screw combined are used for tibial fixation of a hamstring autograft ACLR should be a consideration when this procedure is performed.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of anterior cruciate ligament injury - Secondary publication

BACKGROUND

This clinical guideline presents recommendations for the management of patients with anterior cruciate ligament (ACL) injury, endorsed by the Japanese Orthopaedic Association (JOA) and Japanese Orthopaedic Society of Knee, Arthroscopy and Sports Medicine (JOSKAS).

METHODS

The JOA ACL guideline committee revised the previous guideline based on "Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014", which proposed a desirable method for preparing clinical guidelines in Japan. Furthermore, the importance of "the balance of benefit and harm" was also emphasized. This guideline consists of 21 clinical questions (CQ) and 23 background questions (BQ). For each CQ, outcomes from the literature were collected and evaluated systematically according to the adopted study design.

RESULTS

We evaluated the objectives and results of each study in order to make a decision on the level of evidence so as to integrate the results with our recommendations for each CQ. For BQ, the guideline committee proposed recommendations based on the literature.

CONCLUSIONS

This guideline is intended to be used by physicians, orthopedic surgeons, physical therapists, and athletic trainers managing ACL injuries. We hope that this guideline is useful for appropriate decision-making and improved management of ACL injuries.

Presoaking of Hamstring Autografts in Vancomycin Decreases the Occurrence of Infection Following Primary Anterior Cruciate Ligament Reconstruction

Background:

Postoperative septic arthritis is an uncommon but potentially devastating complication after anterior cruciate ligament (ACL) reconstruction. Our group started presoaking grafts with vancomycin to decrease this risk.

Purpose:

To compare the rate of septic arthritis in primary hamstring autograft ACL reconstruction with and without vancomycin-presoaked grafts.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Consecutive periods were studied, inclusive of April 2013 through October 2015 (pre-vancomycin protocol) and November 2015 through May 2018 (vancomycin protocol). A total of 490 patients were included in the study: 230 in the pre-vancomycin protocol and 260 in the vancomycin protocol. All patients who underwent a primary hamstring autograft ACL reconstruction by 2 senior surgeons during the periods studied were included. The final outcome studied was occurrence of highly probable postoperative septic arthritis in both groups. Diagnosis of probable septic arthritis was made by clinical diagnosis as well as cytological analysis of joint aspiration (cell count >50,000/μL and >90% neutrophils). Statistical analysis was performed with the Fisher exact test. Significance was set at P < .05.

Results:

Four cases of probable postoperative septic arthritis were noted in the pre-vancomycin protocol (1.7%; 2 cases per surgeon), while no cases of septic arthritis were noted in the vancomycin protocol during the study period (P < .05). Diagnosis was made at a mean 21.7 days (range, 16-25 days). Staphylococcus epidermidis was isolated in 2 cases, and in the other 2 cases, no organism was isolated.

Conclusion:

Presoaking of hamstring autografts in vancomycin for primary ACL reconstruction prevented the occurrence of postoperative septic arthritis during the study period as compared with no soaking of the grafts.

Biomechanical and microbiological effects of local vancomycin in anterior cruciate ligament (ACL) reconstruction: a porcine tendon model

INTRODUCTION

Although there is increasing evidence for the successful use of local vancomycin applied by soaked compresses during ACL reconstruction, there are still little data on its microbiological and biomechanical effects. Furthermore, exact dosage of vancomycin with respect to tendon stability and microbiological effectivity is still unknown.

MATERIALS AND METHODS

63 porcine flexor digitorum profundus tendons were harvested under sterile conditions from fresh cadaver legs. After contamination with Staphylococcus epidermidis (S. epidermidis), tendons were wrapped into sterile compresses moistened with different concentrations of vancomycin for 10 or 20 min. Sterile sodium chloride was used for control. After treatment, tendons were rolled onto blood-agar plates to test for residual bacterial contamination and tested for maximum load and stiffness using a uniaxial testing device with cryo-clamps for tendon fixation. Agar plates were checked after 1 week of culture at 36 °C for signs of bacterial growth.

RESULTS

When applying vancomycin for only 10 min, bacterial contamination was found in all dosage groups ranging from 28.6% contamination (n = 2 of 7 tendons) when using 10 mg/ml up to 85.7% (n = 6 of 7 tendons) when using 1 mg/ml. Applying vancomycin-soaked compresses for 20 min, bacterial contamination was still found in the groups using 1 mg/ml and 2.5 mg/ml (contamination rate 85.7 and 42.9% respectively). When using 5 mg/ml and 10 mg/ml, no bacterial contamination could be perceived after 7 days of culture. With regard to biomechanical properties, no differences were found regarding maximum load or Young's modulus between groups.

CONCLUSIONS

This study showed no signs of biomechanical impairment of porcine flexor tendons after the use of vancomycin wraps with concentration ranging from 1 to 10 mg/ml for 10 or 20 min at a time zero testing. Contamination with S. epidermidis was cleansed in 100% of tendons when using at least 5 mg/ml of vancomycin for 20 min.

Anterior cruciate ligament reconstruction complicated by Propionibacterium acnes infection: case series

Anterior cruciate ligament (ACL) reconstruction is one of the most commonly performed orthopaedic procedures. While generally successful, failure resulting in revision surgery is reported to be between 1.9 - 4.9%. However, when not related to traumatic re-injury, failure mechanism is poorly understood. One potential but understudied mechanism of ACL reconstruction failure is infection. We describe three patients with previous ACL reconstructions who later developed infection with Propionibacterium acnes. Two cases presented with knee pain and swelling, and one presented with instability. While only two of the three cases received antibiotic treatment, all three cases were free of knee and infectious symptomatology at most recent follow-up. P. acnes infection may represent one potential mechanism for biologic failure of ACL reconstruction and anaerobic operative cultures may be used to identify its presence.

Septic Arthritis After Anterior Cruciate Ligament Reconstruction: How Important Is Graft Salvage?

BACKGROUND

Septic arthritis (SA) of the knee after anterior cruciate ligament reconstruction (ACLR) is a rare but potentially devastating condition. In certain cases, graft removal becomes necessary.

PURPOSE

To evaluate clinical, subjective, and radiologic outcomes of patients with SA after ACLR and assess whether graft retention has superior clinical results as compared with graft removal.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All patients who were at least 12 months out from arthroscopic treatment of SA after isolated ACLR at our institution were eligible for inclusion. Patients were categorized into 2 groups: group 1, patients with initial graft retention; group 2, patients with initial graft removal. Group 2 was subdivided into 2 groups: group 2a, patients with graft reimplantation; group 2b, patients without graft reimplantation. Objective and subjective assessments were obtained at follow-up, including the International Knee Documentation Committee (IKDC) knee examination form, KT-1000 arthrometer measurements, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score, Lysholm score, and IKDC subjective evaluation. Radiologic assessment was performed with pre- and postoperative magnetic resonance imaging.

RESULTS

Of the 41 patients included, 33 (81%) were available for follow-up at a mean ± SD 54.7 ± 24.4 months at an age of 28.4 ± 9.3 years. When compared with patients from group 2 (n = 12), patients from group 1 (n = 21) obtained significantly better results on the objective IKDC score (normal or nearly normal: group 1, 66.6%; group 2, 36.4%; P = .047) and KT-1000 measurements (group 1, 1.3 ± 1.0 mm; group 2, 2.9 ± 1.5 mm; P = .005). Group 1 also scored better than group 2 on the Lysholm ( P = .007), IKDC subjective ( P = .011), and WOMAC ( P = .069) measures. Between groups 2a (n = 4) and 2b (n = 8), no significant differences in outcomes could be detected ( P values, .307-.705), although patients with anterior cruciate ligament graft reimplantation showed a clear tendency toward better results in objective and not subjective parameters. Magnetic resonance imaging evaluation showed higher rates of cartilage damage and meniscal tears among patients with graft resection versus graft retention.

CONCLUSION

Patients with graft retention showed superior postoperative results when compared with patients who underwent initial graft resection, although subanalysis showed comparable outcomes between graft retention and reimplantation. Thus, while graft-retaining protocols should have the highest priority in the treatment of SA after ACLR, graft reimplantation should be performed in cases where graft resection becomes necessary, to avoid future cartilage and meniscal lesions. Finally, further studies with larger numbers of patients are needed to gain a better understanding of the outcomes of patients with SA after ACLR.

Anterior Cruciate Ligament Graft Removal Versus Retention in the Setting of Septic Arthritis After Reconstruction: A Systematic Review and Expected Value Decision Analysis

PURPOSE

To provide further guidance on the optimal decision between anterior cruciate ligament (ACL) graft removal versus retention in the setting of septic arthritis following reconstruction using an expected value decision analysis.

METHODS

A systematic review and expected value decision analysis and sensitivity analyses were performed to quantify the clinical decision. A decision tree was created with 5 outcomes of interest: nonoperative complications, revision surgery, early reoperation, late reoperation, and "well." Pooled probabilities of each outcome were generated through a systematic literature review. We included only peer-reviewed studies, published in English, with at least 6 months of follow-up. One hundred randomly selected volunteers were given descriptions of the clinical scenario, the 2 treatment options, and outcomes of interest. Patients younger than 18 and older than 50 years and those previously treated for either ACL injury or septic arthritis, or both, were excluded from the analysis to minimize bias. These hypothetical patients indicated preferences for each outcome on a visual analog scale and responses were averaged to generate overall "utility values." Fold-back analysis summed products of pooled outcomes probabilities with respective averaged utility values. The resulting overall expected values for graft removal and debridement were compared, with the highest expected value considered to be superior. We then performed 1-way sensitivity analyses to mitigate sample bias.

RESULTS

Fold-back analysis revealed graft removal to be strongly favored over retention, with overall expected values of 17.2 and 8.64, respectively. The most important contributor to the difference in overall expected values was late reoperation (8.59 vs 2.50 for removal and retention, respectively). Despite adjustments made to the rates of revision and early reoperation during the 1-way sensitivity analyses, graft removal remained the optimal strategy.

CONCLUSIONS

This expected value decision analysis revealed that ACL graft removal was strongly favored by patients over graft retention in the setting of postoperative septic arthritis when consideration was given to the probabilities of wellness, nonoperative complications, revision surgery, early reoperation, and late reoperation. Sensitivity analysis revealed that although variation in rates of other outcomes did not impact this preference, the rate of late reoperation had a substantial impact. Only a sizable increase in the probability of late reoperation (from 0% to 60%) after graft removal would cause potential patients to favor graft retention.

LEVEL OF EVIDENCE

Level IV, systematic review and decision analysis.

Septic Arthritis After Anterior Cruciate Ligament Reconstruction: Clinical and Functional Outcomes Based on Graft Retention or Removal

Background:

There remains a debate over whether to retain the index anterior cruciate ligament (ACL) graft in the setting of septic arthritis.

Purpose:

To evaluate and compare clinical outcomes for the treatment of septic arthritis after ACL reconstruction (ACLR) in those with and without early graft retention.

Study Design:

Case series; Level of evidence, 4.

Methods:

The Military Health System was queried for all ACLR procedures performed between 2007 and 2013. Inclusion criteria required active military status, primary ACLR with secondary septic arthritis, and minimum 24-month surveillance. Demographic, clinical, and surgical variables were evaluated using descriptive statistics and regression analysis for factors influencing selected outcomes.

Results:

Of 9511 ACLR procedures, 31 (0.32%) were identified as having secondary septic arthritis requiring urgent arthroscopic irrigation and debridement and intravenous antibiotics (mean, 6.3 weeks). The majority (62%) were treated in the subacute (2 weeks to 2 months) setting. Index ACLR was performed with a hamstring autograft (n = 17, 55%), soft tissue allograft (n = 11, 35%), and patellar tendon autograft (n = 3, 10%). The graft was retained in 71% (n = 22) of patients, while 29% (n = 9) underwent early graft debridement. At a mean 26.9-month follow-up, 48% of patients (n = 15) had returned to the military. Graft removal was not predictive of return to active duty (P = .29). The presence of postoperative complications, including symptomatic postinfection arthritis (22.6%) and arthrofibrosis (9.7%), was the only variable predictive of inability to return to duty (odds ratio, 27.5 [95% CI, 3.24-233.47]; P = .002). Seven of 9 patients who underwent graft debridement underwent revision ACLR, and all 7 had stable knees at final follow-up compared with 68% (15/22) in the graft retention group.

Conclusion:

Arthroscopic debridement with early graft removal and staged revision ACLR remains a viable option for restoring knee stability (100%), although the rate of return to active duty was low in the graft resection group (33%). The risk of knee laxity did not differ based on early graft retention. Time to presentation with graft retention was not associated with a decreased rate of graft laxity.

Allograft Augmentation of Hamstring Autograft for Younger Patients Undergoing Anterior Cruciate Ligament Reconstruction

BACKGROUND

Younger patients and those with smaller hamstring autograft diameters have been shown to be at significantly greater risk of graft failure after anterior cruciate ligament (ACL) reconstruction. To date, there is no information in the literature about the clinical success and/or cost-effectiveness of increasing graft diameter by augmenting with semitendinosus allograft tissue for younger patients.

HYPOTHESIS

Hybrid hamstring grafts are a cost-effective treatment option because of a reduced rate of graft failure.

STUDY DESIGN

Cohort study (economic and decision analysis); Level of evidence, 3.

METHODS

We retrospectively identified patients younger than 18 years who had undergone ACL reconstruction by a single surgeon between 2010 and 2015. During this period, the operating surgeon's graft selection algorithm included the use of bone-patellar tendon-bone (BTB) autografts for the majority of patients younger than 18 years. However, hamstring autografts (hamstring) or hybrid hamstring autografts with allograft augment (hybrid) were used in skeletally immature patients and in those whom the surgeon felt might have greater difficulty with postoperative rehabilitation after BTB graft harvest. Patient demographics, graft type, graft diameter, the time the patient was cleared to return to activity, and the need for secondary surgical procedures were compared between the hamstring and hybrid groups. The clinical results were then used to assess the potential cost-effectiveness of hybrid grafts in this select group of young patients with an ACL injury or reconstruction.

RESULTS

This study comprised 88 patients (hamstring group, n = 46; hybrid group, n = 42). The 2 groups did not differ in terms of age, sex, timing of return to activity, or prevalence of skeletally immature patients. Graft diameters were significantly smaller in the hamstring group (7.8 vs 9.9 mm; P < .001), which corresponded with a significantly greater rate of graft failure (13 of 46 [28.3%] vs 5 of 42 [11.9%]; P = .049). As a result of the reduced revision rate, the hybrid graft demonstrated incremental cost savings of US$2765 compared with the hamstring graft, and the hybrid graft was the preferred strategy in 89% of cases.

CONCLUSION

Driven by increased graft diameters and the reduced risk of revision, hybrid grafts appear to be a more cost-effective treatment option in a subset of younger patients with an ACL injury.

Clinical and arthrometric outcomes of an anatomic outside-in single-bundle anterior cruciate ligament reconstruction using a retrodrill

BACKGROUND

The main option to perform an anatomic anterior cruciate ligament (ACL) reconstruction is the anteromedial portal (AMP) technique. It has several reported complications (iatrogenic chondral injury, posterior-wall blowout, short sockets, increased risk of injury to common peroneal nerve). In an attempt to avoid these complications the outside-in (OI) technique was revived with the addition of a retrodrill. The aim of this study is to evaluate the clinical and arthrometric outcomes of a series of anatomical OI single bundle ACL reconstruction using a retrodrill.

METHODS

Prospective case series. KT-1000 and Pivot Shift Test were done at 24 months follow-up. International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores preoperatively and at final follow-up. Complications were reported. Statistical analysis was done with t-test.

RESULTS

275 knees of 200 (73%) males and 75 (27%) females were enrolled in the study. Mean age 29.1 years (15-54). Mean follow-up 34.5 months (24-49). Mean preoperatively Lysholm Score 62 (25-95) versus 95 (76-100) at final follow-up (p<0.001) Mean preoperatively IKDC score 60 (26.4-90.8) versus 92 (59.8-100) at final follow-up (p<0.001) Mean Tegner activity Score pre injury 5 versus 5 at final follow-up. (p=0.59) Mean KT-1000 side-to-side difference 2mm (1-6). Pivot Shift test negative in 243 patients (90%); positive in 32 (10%) patients. 13 (5%) ACL re-ruptures. 2 (0.7%) infections. No other complications were reported.

CONCLUSION

OI single bundle anatomic ACL reconstruction using a retrodrill is a valid and safe option that avoids the complications reported with the AMP technique.

Graft salvage following infected anterior cruciate ligament reconstruction

Aims

To examine the rates of hamstring graft salvage with arthroscopic debridement of infected anterior cruciate ligament (ACL) reconstruction as reported in the literature and discuss functional outcomes.

Materials and Methods

A search was performed without language restriction on PubMed, EMBASE, Ovid, CINAHL and Cochrane Register of Controlled Trials (CENTRAL) databases from their inception to April 2015. We identified 147 infected hamstring grafts across 16 included studies. Meta-analysis was performed using a random-effects model to estimate the overall graft salvage rate, incorporating two different definitions of graft salvage.

Results

The graft salvage rate was 86% (95% confidence intervals (CI) 73% to 93%; heterogeneity: tau2 = 1.047, I2 = 40.51%, Q = 25.2, df = 15, p < 0.001), excluding ACL re-ruptures. Including re-ruptures as failures, the graft salvage rate was 85% (95% CI 76% to 91%; heterogeneity: tau2 = 0.099, I2 = 8.15%, Q = 14.15, df = 13, p = 0.36).

Conclusions

Arthroscopic debridement combined with antibiotic treatment can lead to successful eradication of infection and graft salvage, with satisfactory functional outcomes in many cases of septic arthritis following ACL reconstruction. Persistent infection despite repeat arthroscopic debridements requires graft removal with the intention of revision ACL surgery at a later stage. Take home message: Arthroscopic debridement combined with antibiotic therapy is an appropriate initial approach in most cases of septic arthritis following ACL reconstruction, achieving graft salvage rates of about 85%. Cite this article: Bone Joint J 2016;98-B:608–15.

Post-arthroscopy septic arthritis: Current data and practical recommendations

Septic arthritis develops after less than 1% of all arthroscopy procedures. The clinical symptoms may resemble those seen after uncomplicated arthroscopy, raising diagnostic challenges. The diagnosis rests on emergent joint aspiration with microscopic smear examination and prolonged culturing on specific media. Urgent therapeutic measures must be taken, including abundant arthroscopic lavage, synovectomy, and the concomitant administration of two effective antibiotics for at least 6 weeks. Preservation of implants or transplants is increasingly accepted, and repeated joint lavage is a component of the treatment strategy. After knee arthroscopy, infection is the most common complication; most cases occur after cruciate ligament reconstruction, and staphylococci are the predominant causative organisms. Emergent synovectomy with transplant preservation and appropriate antibiotic therapy ensures eradication of the infection in 85% of cases, with no adverse effect on final functional outcomes. After shoulder arthroscopy, infection is 10 times less common than neurological complications and occurs mainly after rotator cuff repair procedures; the diagnosis may be difficult and delayed if Propionibacterium acnes is the causative organism. The update presented here is based on both a literature review and a practice survey. The findings have been used to develop practical recommendations aimed at improving the management of post-arthroscopy infections, which are exceedingly rare but can induce devastating functional impairments.

Managing septic arthritis after knee ligament reconstruction

PURPOSE

Joint infection after anterior cruciate ligament (ACL) reconstruction is uncommon but has potentially serious consequences for the graft and articular cartilage. Most recently published series are in agreement that an urgent arthroscopic washout and antibiotic treatment are mandatory to preserve both graft and cartilage. However, several questions have not as yet been touched upon.

METHODS

We performed a literature review to assess the most interesting series published about this issue.

RESULTS

In this review, a management protocol is first presented that discusses the different diagnostic parameters to consider and surgical and antibiotic treatment suggested according to the literature. Outcomes published in different series are also discussed.

Functional Outcome and Graft Retention in Patients With Septic Arthritis After Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To provide a comprehensive review of clinical and functional outcomes after treatment for septic arthritis after anterior cruciate ligament reconstruction.

METHODS

A systematic review of the literature was performed. Two reviewers assessed and confirmed the methodologic quality of each study. Studies that met the inclusion criteria were assessed for pertinent data, and when available, similar outcomes were combined to generate frequency-weighted means.

RESULTS

Nineteen studies met the inclusion and exclusion criteria for this review, reporting on a total of 203 infected knees. The mean age was 27.5 years and the mean length of follow-up was 44.2 months, with male patients comprising 88% of the population. Hamstring and bone-patellar tendon-bone autografts were used in 63% and 33% of patients, respectively, with 78% of patients retaining their grafts. The studies reported mean flexion and extension deficits of 5.8° and 1.0°, respectively, and laxity testing showed a mean difference of 1.9 mm. The studies reported mean Lysholm, International Knee Documentation Committee, and Tegner scores of 82.1, 68.2, and 5.6, respectively. Of the patients, 83% reported an ability to return to activities of daily living whereas 67% reported a return to their preinjury level of athletics. Evidence of new degenerative changes was seen in 22% of patients.

CONCLUSIONS

Septic arthritis after anterior cruciate ligament reconstruction remains a very infrequent event, affecting 0.5% of patients. On average, outcomes in these patients are comparable with those in patients in whom infection does not develop, including postoperative range of motion, residual instability, Lysholm scores, and return to preinjury level of activity. These patients do exhibit decreased International Knee Documentation Committee scores compared with patients without septic arthritis, however. The impact of this differential is not clear, but this scoring difference suggests that septic arthritis may be associated with more severe symptoms and reduced functional outcomes. In addition, there is limited evidence suggesting that septic arthritis leads to early degenerative changes found on imaging.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.