Hamstring autografts are associated with a high rate of contamination in anterior cruciate ligament reconstruction

Semitendinosus tendons are commonly contaminated with skin flora during graft harvest for anterior cruciate ligament reconstruction

PURPOSE

To investigate the rate of bacterial contamination of semitendinosus (ST) tendons during graft harvest in anterior cruciate ligament reconstruction (ACLR), in order to precisely specify the underlying pathogens and obtain data on their susceptibility to potential antibiotics.

METHODS

In a prospective study, a total of 59 consecutive patients undergoing primary ACLR were recruited from one centre. No patient had history of previous surgery to the knee or showed clinical signs of infection. Four tissue samples of harvested ST tendons for anterior cruciate ligament (ACL) autografts (case group; ST) were examined for evidence of bacterial colonisation and compared to four tissue samples of the native ACL as negative controls (control group; ACL). Three of the respective samples were subjected to cultural microbiological examination and one to 16S rRNA-PCR. Antibiotic susceptibility testing was performed for each pathogen that was identified.

RESULTS

A total of 342 samples were analysed by culture. Significantly more patients showed a positive culture of the ST (33.9%; n = 20/59) compared to 3.4% of patients (n = 2/59) with positive culturing of the ACL (p < 0.0001). Including 16S rRNA-PCR, in a total of 42.4% (25/59) of patients, bacteria were detected in at least one ST sample either by PCR and/or culture. All species found (n = 33) belong to the typical skin flora with Staphylococcus epidermidis (39.4%; n = 13/33) being the most common species, followed by Staphylococcus capitis (24.2%; n = 8/33). All tested isolates (n = 29) were susceptible to vancomycin (29/29, 100%), 69% (n = 20/29) to oxacillin and 65.5% (n = 19/29) to clindamycin.

CONCLUSION

ST autografts for ACLR were commonly contaminated with skin commensal bacteria during harvest. One-third of the isolates showed resistance to typical perioperative intravenous antibiotics, whereas all isolates were sensitive to vancomycin. Therefore, routine prophylactic decontamination of all hamstring autografts before implantation should be recommended, preferably with topical vancomycin.

LEVEL OF EVIDENCE

Level III.

A Systematic Review and Meta-analysis of Risk Factors for an Infection After Anterior Cruciate Ligament Reconstruction

Background

Identifying risk factors for an infection after anterior cruciate ligament reconstruction (ACLR) and following targeted preventive strategies can effectively reduce this potentially serious complication.

Purpose

To perform a systematic review and meta-analysis to identify the risk factors for an infection after ACLR.

Study Design

Systematic review; Level of evidence, 4.

Methods

The PubMed, Embase, and Web of Science databases were searched from inception to September 1, 2022, for prospective and retrospective studies investigating risk factors for any type of infection after ACLR. Odds ratios (ORs) or mean differences were calculated for potential risk factors if ≥2 studies assessed the same risk factor. A qualitative analysis of variables was performed if a meta-analysis could not be conducted.

Results

A total of 17 studies with 141,991 patients were included in this review. The overall pooled infection rate was 0.86% (range, 0.24%-5.50%). There were 20 risk factors identified for analysis. Of these, 7 variables independently increased the odds of an infection after ACLR: (1) male sex (OR, 1.90 [95% CI, 1.33-2.73]), (2) diabetes (OR, 2.69 [95% CI, 1.66-4.35]), (3) hamstring tendon autograft (OR, 2.51 [95% CI, 2.03-3.10]), (4) revision ACLR (OR, 2.31 [95% CI, 1.22-4.37]), (5) professional athlete status (OR, 6.21 [95% CI, 1.03-37.38]), (6) lateral tenodesis (OR, 3.45 [95% CI, 1.63-7.28]), and (7) corticosteroid use (OR, 7.83 [95% CI, 3.68-16.63]). No significant associations were found between postoperative infections and age, body mass index, smoking, meniscal repair, or outpatient surgery.

Conclusion

This review revealed that an increased risk of infections after ACLR was associated with male sex, diabetes, hamstring tendon autograft, revision surgery, professional athlete status, lateral tenodesis, and steroid use. Knowledge of the risk factors associated with an infection after ACLR may facilitate the identification of high-risk cases and the implementation of preventive measures to mitigate the serious consequences of this complication.

Incidence of Surgical Site Infection Despite Preoperative Cefazolin Administration in Total Knee Arthroplasty Patients: A Tertiary Hospital Experience

INTRODUCTION

Surgical site infection (SSI) is an infection that occurs after surgery on the incision site. Cefazolin is an old-generation antibiotic that decreases the risk of SSI. This study aimed to determine the relationship between the incidence of SSI, cefazolin administration, and the factors contributing to the relationship between them.

METHODS

This is a retrospective study that used a data collection sheet to collect variables from the medical records of patients who underwent total knee arthroplasty (TKA) between 2016 and 2020. We looked mainly for the type of antibiotics given preoperatively, the number of doses given, discontinuation of antibiotics postoperatively, length of hospital stay, intensive care unit (ICU) admission, and SSI occurrence.  Results: A total of 195 patients were included. The majority (87.8%) were given two grams of cefazolin. Patients who have taken one gram of cefazolin had a slightly higher hospital stay than those who took two grams. However, all the patients did not develop an SSI.

CONCLUSION

There was no incidence of SSI despite preoperative cefazolin administration in TKA patients. Patients who received higher doses of cefazolin had a shorter length of hospital stay.

Recommendations on diagnosis and antimicrobial treatment of infections after anterior cruciate ligament reconstruction (ACL-R) endorsed by ESSKA and EBJIS

Infection after anterior-cruciate ligament reconstruction (ACL-R) is a rare but devastating complication affecting predominantly young and sportive individuals. A timely and correct diagnosis as well as an optimized management are paramount to circumvent serious sequelae and compromise in life quality. These recommendations are primarily intended for use by infectious disease specialists and microbiologists, but also orthopedic surgeons and other healthcare professionals who care for patients with infections after ACL-R. They are based on evidence mainly originating from observational studies and opinions of experts in the field and cover the management of infections after ACL-R with a special focus on etiology, diagnosis, antimicrobial treatment and prevention. Comprehensive recommendations on prevention, surgical treatment and rehabilitation are presented separately in a document primarily addressing orthopedics professionals.

Allograft contamination during suture preparation for anterior cruciate ligament reconstruction: an ex vivo study

PURPOSE

Effects of suture preparation on graft contamination remain unknown in anterior cruciate ligament reconstruction (ACLR). This study aimed to evaluate the incidence of allograft contamination at different time points of graft preparation and investigate differences in contamination between different sites of the allografts.

METHODS

Fourteen hamstring tendon (HT), 9 quadriceps tendon (QT), and 9 bone-patellar tendon-bone (BTB) allografts were harvested, sterilised, and stored following routine procedures. Graft suture preparation was performed with baseball stitching for soft tissue and bone drilling for bone plug. The time was recorded simultaneously. The graft was kept moist in a standard operating room environment for 30 min after the initiation of preparation. The specimens were obtained from the middle and both ends of each graft for culture at three different time points: pre-suturing, post-suturing, and 30 min after the initiation of preparation. A total of 192 specimens were transferred to the microbiology laboratory for culture, identification, and semi-quantitative assessment. Culture results were classified as negative, poor, and abundant based on the extent of growth. Contamination level was recorded as low or high corresponding to culture results of poor or abundant.

RESULTS

The duration of suture preparation was 348, 301, and 246 s for HT, QT, and BTB (P = 0.090). The specimens had a positive culture rate of 41/192 (21.4%), of which 21 were from the ends and 20 from the middle. More positive samples with abundant bacterial growth were detected from the ends than from the middles post-suturing (7/8 vs. 1/7, P = 0.010) and at 30 min (6/11 vs. 0/11, P = 0.012). The total graft contamination rate was significantly higher at 30 min (19/32, 59.4%) than pre-suturing (4/32, 15.6%) and post-suturing (9/32, 28.1%) (P < 0.001). The contamination rate with abundant bacterial growth was higher post-suturing (7/32, 21.9%) than pre-suturing (0%). No statistically significant differences were found among the three types of allografts.

CONCLUSION

The contamination rate increases significantly at 30 min compared with pre-suturing and post-suturing. Suture preparation may have introduced the high-level contamination, to which the ends of the graft were more prone than the middle. Therefore, routine prophylactic decontamination after suture preparation should be considered, especially for the ends of the grafts.

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.

Contamination and Decontamination of Autologous Bone in the Operating Room: A Systematic Review

OBJECTIVE

To perform a systematic review of the literature to determine the rate of contamination of autologous bone fragments inadvertently dropped on the operating room floor, the microbial profile (contaminating organism), and the outcome of intraoperative decontamination techniques in terms of effectiveness and cellular toxicity.

DATA SOURCES

PubMed, Medline, and Embase were searched for English literature published from 1990 through 2020 using terms such as "bone graft contamination," "dropped osteoarticular fragments," "autogenous bone decontamination," and similar interchangeable words.

STUDY SELECTION

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Inclusion criteria consisted of all studies on contamination of host bone fragments, means and/or rate of autologous bone contamination in operating rooms, microbial analysis of contaminated bone autograft, outcome of decontamination, and cellular viability after decontamination.

DATA EXTRACTION

All potentially eligible studies underwent a full-text review and cross-referencing after title and abstract screening. Data on authors, publication year, study type, means and rate of contamination, microbial profile, decontamination technique, and effectiveness and cellular toxicity outcomes were extracted.

DATA SYNTHESIS

Analysis and synthesis of data were performed on Microsoft Excel 2016.

CONCLUSION

The rate of contamination for dropped osteoarticular or osteochondral host fragment approached 40%. Staphylococcus epidermidis was the most common organism contaminating the bone graft when dropped on the operating room floor. A 5-minute bath in 10% povidone-iodine solution followed by 1-minute bulb syringe lavage with normal saline has proved successful in decontamination and maintenance of cellular viability.

LEVEL OF EVIDENCE

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

Lower incidence of post-operative septic arthritis following revision anterior cruciate ligament reconstruction with quadriceps tendon compared to hamstring tendons

PURPOSE

To determine and compare the incidence of post-operative septic arthritis following revision anterior cruciate ligament reconstruction (R-ACLR) with autologous quadriceps tendon (with patellar bone block) compared to autologous hamstring tendons (semitendinosus and gracilis).

METHODS

A total of 1638 isolated R-ACLR with either autologous hamstring tendons (n = 1004, 61.3%) or quadriceps tendon (n = 634; 38.7%) were performed between 2004 and 2017 and were retrospectively analysed with regard to the occurrence of post-operative septic arthritis. The technique of R-ACLR did not significantly change during the years of the study. All patients received pre-op i.v.antibiotics, but no presoaking of the grafts in vancomycin was performed in the years of the study. The individual decision of graft choice was based on graft availability, tunnel position and the presence of tunnel widening. Generally, hamstring tendons were preferred. There were no clinically relevant differences between the groups regarding gender or age. Routine follow-up examination was performed 6 weeks after the index operation (follow-up rate 96.5%), and patients unsuspicious for septic arthritis at that time were classified as non-infected.

RESULTS

Fourteen patients with septic arthritis were identified, resulting in an overall incidence of 0.85%. There was one patient with septic arthritis in the quadriceps tendon group (incidence: 0.16%) and 13 patients in the hamstring tendons group (incidence: 1.29%), respectively. The difference was significant (p = 0.013).

CONCLUSION

In this series, the incidence of post-operative septic arthritis after R-ACLR was lower when quadriceps tendon graft was used compared to hamstring tendon grafts.

LEVEL OF EVIDENCE

III.

Soaking of autografts in vancomycin is highly effective in preventing postoperative septic arthritis after revision anterior cruciate ligament reconstruction

PURPOSE

To determine and compare the incidence of postoperative septic arthritis following revision anterior cruciate ligament reconstruction (R-ACLR) with and without soaking of the graft in vancomycin solution prior to implantation in a large single-centre series.

METHODS

A total of 2155 isolated R-ACLR with autologous tendons were performed from 2004 to 2019 and were reviewed with regard to the occurrence of postoperative septic arthritis. From February 2017 onwards, all grafts were wrapped in a vancomycin-soaked (5 mg/ml) gauze swab between harvest and implantation (517 patients, treatment group (2), prospectively followed). These were compared to 1638 patients before that date (control group (1), retrospectively evaluated). The technique of R-ACLR did not significantly change during the years of the study. Hamstring tendons were used in 1310 patients (60.8%) and quadriceps tendons with patellar bone block were used in 845 patients (39.2%), respectively, with no difference between the groups (n.s.). Routine follow-up examination was performed 6 weeks postoperatively (follow-up rate 96.5%), and patients with no treatment for septic arthritis until that time were classified as non-infected.

RESULTS

There were 14 cases of postoperative septic arthritis in group 1 (incidence 0.9%), and none in group 2 (incidence 0.0%), respectively. The difference was significant (p = 0.029).

CONCLUSION

Soaking of the graft in vancomycin solution prior to implantation dramatically reduces the incidence of postoperative septic arthritis in R-ACLR.

LEVEL OF EVIDENCE

III.

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.