Management of septic arthritis after arthroscopic anterior cruciate ligament reconstruction using a standard surgical protocol

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.

Extraarticular infection 9 years after anterior cruciate ligament reconstruction. Case report

Extraarticular infection after anterior cruciate ligament reconstruction (ACLr) is a rare condition with challenging diagnosis because the symptoms are milder and more insidious when compared to septic arthritis. When late (>2 months after surgery), it tends to be associated with osteomyelitis, requiring more extensive surgical debridement and hardware removal. We report a case of extraarticular infection after ACLr, in the acute phase affecting the tibial site and 9 years after index surgery affecting around the femur site. There was no progression to osteomyelitis at any of the sites. The infection developed a large posterolateral encapsulated abscess, with the endobutton plate loose inside it with its loop intact. In addition to the absence of osteomyelitis progression, there was no sinus tract formation, graft or joint involvement. With open debridement and antibiotic therapy, the patient returned to his activities without limitations. The reported case highlights that extraarticular infection after ACLr, while rare, can be challenging to diagnose and treat. However, with appropriate treatment, it can lead to good results with no functional limitations.

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.

Influence of Staphylococcus epidermidis biofilm on the mechanical strength of soft tissue allograft

We sought to determine the impact of bacterial inoculation and length of exposure on the mechanical integrity of soft tissue tendon grafts. Cultures of Staphylococcus epidermidis were inoculated on human tibialis posterior cadaveric tendon to grow biofilms. A low inoculum in 10% growth medium was incubated for 30 min to replicate conditions of clinical infection. Growth conditions assessed included inoculum concentrations of 100, 1000, 10,000 colony-forming units (CFUs). Tests using the MTS Bionix system were performed to assess the influence of bacterial biofilms on tendon strength. Load-to-failure testing was performed on the tendons, and the ultimate tensile strength was obtained from the maximal force and the cross-sectional area. Displacements of tendon origin to maximal displacement were normalized to tendon length to obtain strain values. Tendon force-displacement and stress-strain relationships were calculated, and Young's modulus was determined. Elastic modulus and ultimate tensile strength decreased with increasing bioburden. Young's modulus was greater in uninoculated controls compared to tendons inoculated at 10,000 CFU (p = 0.0011) but unaffected by bacterial concentrations of 100 and 1000 CFU (p = 0.054, p = 0.078). Increasing bioburden was associated with decreased peak load to failure (p = 0.043) but was most significant compared to the control under the 10,000 and 1000 CFU growth conditions (p = 0.0005, p = 0.049). The presence of S. epidermidis increased elasticity and decreased ultimate tensile stress of human cadaveric tendons, with increasing effect noted with increasing bioburden.

Risk factors for postoperative surgical site infections after anterior cruciate ligament reconstruction: a systematic review and meta-analysis

OBJECTIVES

The primary aim was to evaluate risk factors for surgical site infections after anterior cruciate ligament reconstruction (ACLR). The secondary aim was to investigate the surgical site infection incidence rate and the mean time to postoperative surgical site infection symptoms.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase and Web of Science were searched from database inception to September 2021 and updated in April 2022.

ELIGIBILITY CRITERIA

Quantitative, original studies reporting potential risk factors for surgical site infections after ACLR were included.

RESULTS

Twenty-three studies with 3871 infection events from 469 441 ACLRs met the inclusion criteria. Male sex (OR 1.78, p< 0.00001), obesity (OR 1.82, p=0.0005), tobacco use (OR 1.37, p=0.01), diabetes mellitus (OR 3.40, p=0.002), steroid use history (OR 4.80, p<0.00001), previous knee surgery history (OR 3.63, p=0.02), professional athlete (OR 4.56, p=0.02), revision surgery (OR 2.05, p=0.04), hamstring autografts (OR 2.83, p<0.00001), concomitant lateral extra-articular tenodesis (OR 3.92, p=0.0001) and a long operating time (weighted mean difference 8.12, p=0.005) were identified as factors that increased the risk of surgical site infections (superficial and deep) after ACLR. Age, outpatient or inpatient surgery, bone-patellar tendon-bone autografts or allografts and a concomitant meniscus suture did not increase the risk of surgical site infections. The incidence of surgical site infections after ACLR was approximately 1% (95% CI 0.7% to 1.2%). The mean time from surgery to the onset of surgical site infection symptoms was approximately 17.1 days (95% CI 13.2 to 21.0 days).

CONCLUSION

Male sex, obesity, tobacco use, diabetes mellitus, steroid use history, previous knee surgery history, professional athletes, revision surgery, hamstring autografts, concomitant lateral extra-articular tenodesis and a long operation time may increase the risk of surgical site infections after ACLR. Although the risk of surgical site infections after ACLR is low, raising awareness and implementing effective preventions for risk factors are priorities for clinicians to reduce the incidence of surgical site infections due to its seriousness.

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.

Effect of Joint Infection After Arthroscopic Single-Bundle ACL Reconstruction With Autologous Hamstring Tendon: A Retrospective Matched MRI Study

Background:

Joint infection after anterior cruciate ligament (ACL) reconstruction is a rare but serious complication.

Purpose:

To assess the effect of joint infection on the graft, cartilage, and bone tunnel using magnetic resonance imaging (MRI) after arthroscopic single-bundle ACL reconstruction with autologous hamstring tendons.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This retrospective matched cohort study included 26 patients who underwent arthroscopic single-bundle ACL reconstruction with hamstring tendon graft at the authors’ institute between January 2002 and December 2017 and developed postoperative joint infection. These patients were matched 1:3 to patients who did not sustain joint infection after ACL reconstruction (control group). MRI scans were collected at the time of follow-up. The following parameters were evaluated: graft signal-to-noise quotient (SNQ); graft signal intensity at the bone-graft interface and within the knee joint; bone tunnel enlargement at the tunnel aperture, midsection, and exit of the tibial and femoral tunnels; and cartilage integrity.

Results:

The average follow-up time was 47.8 months in the infection group and 48.5 months in the control group. Compared with the control group, the infection group had a significantly higher SNQ (20.01 ± 12.08 vs 7.61 ± 6.70; P = .014) as well as a higher signal intensity at the bone-graft interface (P = .037) and higher Howell grade (P = .031). The mean enlargement at the femoral tunnel aperture was 31.20% ± 26.76% in the infection group and 19.22% ± 20.10% in the control group (P = .037). The articular cartilage of the patellofemoral and lateral femorotibial joints showed more degenerative change in the infection group.

Conclusion:

Study findings indicated that graft ligamentization and incorporation graft maturity were inferior in patients who experienced a joint infection after ACL reconstruction compared with patients who did not.

[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.

Effects of Temperature and Volume of Intraoperative Normal Saline Irrigation on Postoperative Pain, Swelling, and Serum Markers of Inflammation in Patients After Elective, Arthroscopic, Single-Bundle Surgical Reconstruction of the Anterior Cruciate Ligament: A Retrospective, Single-Center Study

BACKGROUND Arthroscopic single-bundle surgical reconstruction of the anterior cruciate ligament (ACL) is often performed electively after 3 weeks of mobilization therapy. The present single-center retrospective study aimed to investigate the effects of temperature and volume of intraoperative normal saline irrigation on postoperative pain and swelling and on serum markers of inflammation following elective, arthroscopic, single-bundle surgical reconstruction of the ACL. MATERIAL AND METHODS Clinical data from 716 patients with non-acute ACL injuries who met the criteria between March 2015 and May 2020 were retrospectively analyzed. The patients were broken into 5 groups, depending on the volume or temperature of intraoperative irrigation with normal saline. At specific times after surgery, pain, knee swelling, and skin temperature were assessed. Postoperative levels of serum C-reactive protein (CRP), interleukin (IL)-1, IL-6, and IL-10 also were measured. RESULTS Visual analog scale (VAS) scores for pain, rates of swelling, and skin temperature differed significantly among the 5 groups at all postoperative time points (P<0.001). The VAS scores(P=0.322) and ratings for swelling (P=0.245), and skin temperature (P=0.093) were not significantly different among the volume groups. There were no significant differences in the VAS scores (P=0.055), swelling ratings (P=0.570), or skin temperatures (P=0.321) among the groups that received irrigation with normal saline at different temperatures. There were no significant differences in postoperative serum levels of CRP, IL-1, IL-6, or IL-10 among the groups (P>0.05). CONCLUSIONS Irrigation with different volumes and temperatures of normal saline did not have a significant effect on postoperative pain, swelling, or serum markers of inflammation.

Inadvertent Debridement of the Medial Patellofemoral Ligament Following Arthroscopic Knee Surgery for Infection: A Case Report

Introduction

Arthroscopic debridement of the knee is usually considered a safe procedure. There are no case reports of medial patellofemoral ligament (MPFL) injury leading to habitual dislocation of the patella following this procedure in the literature.

Case Presentation

A 35-year-old male presented with complaints of habitual dislocation of the left patella, which he noticed after multiple arthroscopic surgeries of the left knee performed elsewhere. He had a history of septic arthritis of the knee following anterior cruciate ligament reconstruction, for which he underwent arthroscopic debridement of the knee twice. After a detailed evaluation, we noticed MPFL medial patellofemoral ligament injury.

Conclusion

The MPFL medial patellofemoral ligament injury occurred as a result of extensive resection of the medial joint capsule while operating for septic arthritis. This rare grave surgical complication emphasizes the care one should take during arthroscopic debridement of the knee.

Soaking of autografts with vancomycin is highly effective on preventing postoperative septic arthritis in patients undergoing ACL reconstruction with hamstrings autografts

PURPOSE

To evaluate the impact of local soaking of the autografts with vancomycin during anterior cruciate ligament (ACL) reconstruction on postoperative infection rates.

METHODS

Between 2003 and 2014 (first study period), 1,242 patients underwent ACL reconstruction using autografts, without soaking them in vancomycin solution, while between 2014 and 2019 (second study period) all ACL autografts in 593 patients were soaked in a 5-mg/ml vancomycin solution, in a territory University Hospital. The same standard treatment of perioperative IV antibiotics was applied in both groups.

RESULTS

Postoperative septic arthritis occurred in seven out of 1,242 patients (0.56%) during the first study period. Bone patellar tendon bone autograft was used in 311 (25%) patients, and hamstring tendon autograft was used in the rest 931 (75%) of the study population during this period. All infected cases were male and had a hamstrings graft implanted. There were no postoperative infections (0%) in 593 ACL reconstructions during the second study period. Bone patellar tendon bone autograft was used in 178 (30%) patients while hamstring tendon autograft was used in the rest 415 (70%) of the study population, during this period. Statistical analysis revealed a significantly reduced postoperative infection rate (p = 0.018) between the two reported periods, with the main impact referring to the use of hamstrings autograft (p = 0.031) for the first study period.

CONCLUSIONS

Septic arthritis following ACL reconstruction can be significantly reduced (or even eliminated) by soaking ACL autografts in a 5 mg/ml vancomycin solution. Of note, this strategy seems to be more effective in the setting of hamstring tendon autograft use, since the risk of postoperative knee infection is significantly higher when this type of graft is used.

Recurrent surgical site infection after anterior cruciate ligament reconstruction: A case report

BACKGROUND

Surgical site infections following anterior cruciate ligament (ACL) reconstruction are an uncommon but potentially devastating complication. In this study, we present an unusual case of recurrent infection of the knee after an ACL reconstruction, and discuss the importance of accurate diagnosis and appropriate management, including the issue of graft preservation versus removal.

CASE SUMMARY

A 33-year-old gentleman underwent ACL reconstruction using a hamstring tendon autograft with suspensory Endobutton fixation to the distal femur and an interference screw fixation to the proximal tibia. Four years after ACL reconstruction, he developed an abscess over the proximal tibia and underwent incision and drainage. Remnant suture material was found at the base of the abscess and was removed. Five years later, he re-presented with a lateral distal thigh abscess that encroached the femoral tunnel. He underwent incision and drainage of the abscess which was later complicated by a chronic discharging sinus. Repeated magnetic resonance imaging revealed a fistulous communication between the lateral thigh wound extending toward the femoral tunnel with suggestion of osteomyelitis. Decision was made for a second surgery and the patient was counselled about the need for graft removal should there be intra-articular involvement. Knee arthroscopy revealed the graft to be intact with no evidence of intra-articular involvement. As such, the decision was made to retain the ACL graft. Re-debridement, excision of the sinus tract and removal of Endobutton was also performed in the same setting. Joint fluid cultures did not grow bacteria. However, tissue cultures from the femoral tunnel abscess grew Enterobacter cloacae complex, similar to what grew in tissue cultures from the tibial abscess five years earlier. In view of the recurrent and indolent nature of the infection, antibiotic therapy was escalated from Clindamycin to Ertapenem. He completed a six-week course of intravenous antibiotics and has been well for six months since surgery, with excellent knee function and no evidence of any further infection.

CONCLUSION

Prompt and accurate diagnosis of surgical site infection following ACL reconstruction, including the exclusion of intra-articular involvement, is important for timely and appropriate treatment. Arthroscopic debridement and removal of implant with graft preservation, together with a course of antibiotics, is a suitable treatment option for extra-articular knee infections following ACL reconstruction.

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.

Development of Multilayered Chlorogenate-Peptide Based Biocomposite Scaffolds for Potential Applications in Ligament Tissue Engineering - An <i>In Vitro</i> Study

In this work, for the first time, chlorogenic acid, a natural phytochemical, was conjugated to a lactoferrin derived antimicrobial peptide sequence RRWQWRMKKLG to develop a self-assembled template. To mimic the components of extracellular matrix, we then incorporated Type I Collagen, followed by a sequence of aggrecan peptide (ATEGQVRVNSIYQDKVSL) onto the self-assembled templates for potential applications in ligament tissue regeneration. Mechanical properties and surface roughness were studied and the scaffolds displayed a Young’s Modulus of 169 MP and an average roughness of 72 nm respectively. Thermal phase changes were studied by DSC analysis. Results showed short endothermic peaks due to water loss and an exothermic peak due to crystallization of the scaffold caused by rearrangement of the components. Biodegradability studies indicated a percent weight loss of 27.5 % over a period of 37 days. Furthermore, the scaffolds were found to adhere to fibroblasts, the main cellular component of ligament tissue. The scaffolds promoted cell proliferation and displayed actin stress fibers indicative of cell motility and attachment. Collagen and proteoglycan synthesis were also promoted, demonstrating increased expression and deposition of collagen and proteoglycans. Additionally, the scaffolds exhibited antimicrobial activity against Staphylococcus epidermis bacteria, which is beneficial for minimizing biofilm formation if potentially used as implants. Thus, we have developed a novel biocomposite that may open new avenues to enhance ligament tissue regeneration.