European Journal of Orthopaedic Surgery & Traumatology https://doi.org/10.1007/s00590-023-03548-4 ORIGINAL ARTICLE Sequential repeated tibial tubercle osteotomy in a two‑stage exchange strategy: a superior approach to treating a chronically infected knee arthroplasty? Pablo S. Corona1,2,3 · Marta Pérez1,4 · Matías Vicente1,2,3 · Oriol Pujol1 · Carles Amat1,2,3 · Lluís Carrera1,2,3,4 Received: 4 January 2023 / Accepted: 10 April 2023 © The Author(s) 2023 Abstract Purpose Surgical approach can impact the reliability of the debridement after a chronic total knee periprosthetic joint infec- tion (PJI), a factor of utmost importance to eradicate the infection. The most adequate knee surgical approach in cases of PJI is a matter of debate. The purpose of this study was to determine the influence of performing a tibial tubercle osteotomy (TTO) in a two-stage exchange protocol for knee PJI treatment. Methods Retrospective cohort study examining patients managed with two-stage arthroplasty due to chronic knee PJI (2010–2019). Performance and timing of the TTO were collected. Primary end-point was infection control with a minimum FU of 12 months and according to internationally accepted criteria. Correlation between TTO timing and reinfection rate was reviewed. Results Fifty-two cases were finally included. Overall success (average follow-up: 46.2 months) was 90.4%. Treatment suc- cess was significantly higher among cases addressed using TTO during the second stage (97.1% vs. 76.5%, p value 0.03). Only 4.8% of the patients relapsed after performing a sequential repeated TTO, that is, during both first and second stages, compared to 23.1% cases in which TTO was not done (p value 0.28). No complications were observed among patients in the TTO group with a significant decrease in soft tissue necrosis (p: 0.052). Conclusion Sequential repeated tibial tubercle osteotomy during a two-stage strategy is a reasonable option and offers high rates of infection control in complex cases of knee PJI with a low rate of complications. Keywords Tibial tubercle osteotomy · Periprosthetic joint infection · Two-stage revision arthroplasty · Infection control Introduction Periprosthetic joint infection (PJI) is one of the most dev- Pablo S. Corona and Marta Pérez have contributed equally in astating complications following total knee arthroplasty producing this paper. (TKA) and one of the most challenging problems an ortho- pedic surgeon faces [1]. * Marta Pérez mpg1403@gmail.com Although direct exchange arthroplasty has been proven a reliable strategy in certain scenarios [2], two-stage recon- 1 Universitat Autònoma de Barcelona (UAB), Orthopaedic struction has been the widely accepted model of care [3]. Surgery Department, Vall d’Hebron University Hospital, However, a superior two-stage treatment algorithm is still Barcelona, Spain lacking, and management of chronic knee PJI remains con- 2 Septic and Reconstructive Surgery Unit (UCSO), troversial [4, 5]. Orthopaedic Surgery Department, Vall d’Hebron University Hospital, Universitat Autònoma de Barcelona (UAB), Surgical debridement quality is of utmost importance Barcelona, Spain in all surgical protocols to eradicate infection [6]. Surgical 3 Musculoskeletal Tissue Engineering Group, Vall d’Hebron approach can impact the reliability of the surgical debride- Research Institute, Barcelona, Spain ment. Several approaches have been proposed, including 4 Surgery Department, Universitat Autònoma de Barcelona an extensile medial parapatellar (EMP) approach and tibial (UAB), Barcelona, Spain tubercle osteotomy (TTO) [7, 8]. The latter approach likely 13 Vol.:(0123456789) European Journal of Orthopaedic Surgery & Traumatology allows better access, especially to the knee’s difficult-to- (ASA) Scale, Charlson’s Comorbidity Index (CCI) [16] reach lateral aspect, thus facilitating more complete debride- and McPherson’s host classification [17] were collected, as ment [9–11]. However, the influence of this approach on were the type of infected prosthesis and number of previous infection control rates after a two-stage strategy has been surgeries. poorly studied, as has the rate of TTO complications in the First-stage and second-stage-related variables; date of infected scenario [9, 12, 13]. surgical procedure, TTO performance, type of spacer (static/ Considering all factors discussed above, we sought to dynamic), final modular reconstruction, microorganisms analyse the influence of the surgical approach in a consecu- and soft tissue reconstructive procedures were reviewed. tive series of chronic knee PJI managed with a two-stage Spacer-stage variables: spacer-related complications, reop- exchange strategy and to study any association between erations and TTO-related complications. Post-operative data performance of a tibial tubercle osteotomy and: (1) risk of included TTO-related complications, need for unexpected overall infection treatment failure; (2) incidence of TTO- reinterventions, infection relapse. related complications; and (3) association of TTO-timing The patients were divided into three groups according with final outcomes. to whether tibial tubercle osteotomy had been performed, Our primary hypothesis is that the use of a sequential and the timing of TTO; Group A: repeated sequential TTO repeated TTO in a two-stage strategy after chronic PJI (during both first and second stages); Group B: single TTO achieves better infection control rate than in cases where an (in either first or second stage) and Group C: no TTO. osteotomy is not performed, without increasing complica- Osteotomy was considered healed when radiographic evi- tion rate. dence of bridging callus formation was observed on lateral radiography. Materials and methods Two‑stage operative technique Study design Members of our centre’s Septic Unit (three surgeons) per- After Institutional Review Board (IRB) approval (date: formed all operations. In the first stage, the earlier prosthesis 13/11/2020, reference number: PR(ATR)283/2020), we and cement were removed. An EMP approach (including conducted a retrospective review to identify all consecutive neither quadriceps snip nor quadriceps turndown) or TTO chronic knee PJIs managed with two-stage revision from was performed; the latter being chosen when a safe mobili- January 2010 through December 2019. In order to homog- zation of the extensor mechanism could not be achieved by enize the sample only cases with a single manufacturer's an EMP approach or when correct visualization of the knee implant system used during the second stage were accepted. was compromised due to stiffness and rigidity. Thorough In this series, a cemented modular rotational hinge revision debridement and irrigation were performed. At least six arthroplasty (CMRH) was used in all cases during the sec- solid samples were obtained for microbiological culture, as ond stage. well as tissue samples for histological examination. The TTO technique (Fig. 1a) is based on the technique Inclusion–exclusion criteria described by Whiteside in 1995 [11] and which can be found elsewhere; osteotomy is normally secured with three wires Two-stage strategy to manage chronic knee PJI. Use of the cerclages, passed behind the tibial stem. same CMRH implant during the second stage. Minimum In the first stage, our technique of choice includes use of follow-up of 12 months after the second stage. All included a mobile prefabricated knee spacer. In such cases, a van- patients had an established diagnosis of chronic PJI accord- comycin-gentamicin prefabricated antibiotic-cement spacer ing to an internationally accepted definition [14]. Chronic (Vancogenx®, Tecres SpA, Sommacampagna, Verona, PJI was defined as any PJI present more than four weeks Italy) is used, fixed with a vancomycin-gentamicin-loaded from the index procedure [15]. Patients who did not fit acrylic bone cement (Vancogenx® bone cement, Tecres all inclusion criteria and those treated with a distal femur SpA, Sommacampagna, Verona, Italy) with an extra dose megaprosthesis during reimplantation were excluded from of powder antibiotic [4]. Usually, a hand-made antibiotic- the study. loaded cement stem (reinforced with a Steinmann pin) is connected to the spacers to increase stability and fill the Outcome variables intramedullary dead space (Fig. 1b, c). In cases of TTO, the stem is mandatory and must bypass the osteotomy by a Primary end-point was infection control rate. Patient demo- minimum of 5 cm to avoid fracture of the tibia [18, 19]. In graphic variables, American Society of Anesthesiologists cases of knee infection with massive bone defects, extensor 13 European Journal of Orthopaedic Surgery & Traumatology antibiotics for 8–10 days, in which we usually used a beta- lactam, or a carbapenem if involvement of multi-resistant microorganism was suspected, associated or not with a gly- copeptide or a lipopeptide. When final microbiological data and proper wound healing was confirmed, antibiotics were switched to oral and maintained for at least 6 weeks. When- ever possible, a combination of rifampicin with a second antibiotic was used for gram-positive infection. If suscepti- ble, the preferred combination was rifampicin plus levoflox- acin in the case of staphylococcal infection. If the selected antibiotic was linezolid, rifampicin was not added, due to the increased metabolism of linezolid which can result in decreased serum levels. In gram-negative infections, when- ever susceptible, oral ciprofloxacin was administered. After cessation of antibiotic treatment, a minimum two-week anti- biotic vacation period was begun. Timing of reimplantation was based on clinical improvements and laboratory values. In the second stage, the spacer was removed, a second Fig. 1  a First stage tibial tubercle osteotomy (TTO) approach. The aggressive debridement was performed, and samples were cerclages pass behind the spacer stem; b anteroposterior and c lateral collected. Either an EMP approach or a TTO was performed. radiography of a prefabricated mobile spacer Joint reconstruction was performed by implantation of a sin- gle design of CMRH prosthesis (Endo-Model®-M, Walde- mechanism disruption, or soft tissue deficiencies, we prefer mar Link GmbH&Co.®; Hamburg; Germany), fixed with to use a static spacer [20] (Fig. 2a, b). Vancogenx® bone cement (Fig. 3a, b). After both first and All patients followed similar post-operative antibiotic second stages, the patient is at rest without flexing the knee protocols, as recommended by an infectious-diseases expert until correct evolution of the surgical incision is verified [21], member of our specialty-dedicated unit. In general, the (this is usually not earlier than 10–14 days). antibiotic treatment was selected according to the suscepti- Following operation, systemic antibiotics against the bility profile of the bacteria present, and following the clini- first-stage-isolated microorganism were administered until cal practice guidelines of the Spanish Society of Infectious availability of microbiological results. If, after seven to ten Diseases and Clinical Microbiology (SEIMC). Regarding days, cultures were deemed negative, antibiotic treatment systemic antibiotics, treatment was initiated with intravenous was withdrawn [4]. Fig. 2  a First stage tibial tubercle osteotomy (TTO) approach with a Fig. 3  a Anteroposterior and b lateral post-operative radiography static spacer; b anteroposterior radiography of the static spacer showing an Endo-Model®-M knee revision prosthesis 13 European Journal of Orthopaedic Surgery & Traumatology Success of the two-stage exchange protocol was defined as infection control according to an internationally accepted definition [22]: (a) healed wound without fistula or drainage Assessed for eligibility (n=69) and no infection recurrence caused by the same organism strain; (b) no subsequent surgical intervention for infection after reimplantation surgery; and (c) no PJI-related mortal- ity. In addition, need for suppressive antibiotic treatment or the onset of another PJI caused by a different microorganism Excluded (n=17) were also considered failure criteria. If one or more of the -Nave joint sepc arthris (n=3) stated criteria was fulfilled, treatment failure was considered -No MSIS' criteria fulfilling (n=2) - Non-cemented component on final implant as established [4]. (n=5) - Distal femur megaprosthesis (n=1) - Lack of minimum follow-up (n=4) - Lack of relevant data (n=2) Statistical analysis Demographic-clinical characteristics were summarized as counts and percentages for categorical variables. Means and confidence intervals were calculated for continuous varia- bles. Normality was tested using the Kolmogorov–Smirnov Included (n=52) test. Groups were compared using the Chi-square or Fisher exact test (analysis of small samples) for categorical vari- ables. Continuous variables were evaluated with the Stu- dent t test and ANOVA test (normal-distribution data), Fig. 4  Flowchart of study cases. MSIS, Musculoskeletal Infection Society and the Wilcoxon–Mann–Whitney test and Kruskal–Wal- lis test (non-normal data). All p values were two-tailed; p values < 0.05 were considered statistically significant. cases (3.8%); there were no spacer breakages. We found no A Kaplan–Meier estimate was conducted for any variable dislocation or fracture among static spacers. identified as a factor for better outcomes. Differences in Regarding microbiological results, coagulase-negative the curves were evaluated with the Tarone–Ware test. R Staphylococcus strains were the most frequent pathogens software was used to perform the aforementioned tests (R in our series, with isolates in 34.6% of cases, followed by Core Team, 2020. R Foundation for Statistical Computing, Propionibacterium Acnes (17,3%) and S. Aureus (9,6%). Vienna, Austria). Further information on PJI-causing microorganisms can be found in Table 2. In 21 cases (40.4%), a repeated sequential TTO was Results performed in the first and second stage (Group A), making it the most frequently selected option in this series. In 18 In our database review, we detected sixty-nine cases of patients (34.6%) a single osteotomy was performed (Group two-stage revision knee arthroplasty. After exclusion of B), predominantly during the second stage (14 cases). In the patients who did not meet selection criteria (Fig. 4), fifty- remaining 13 patients (25%), the selected approach was an two cases of chronic knee PJI who had undergone a two- EMP approach, without TTO (Group C) (Table 3). Differ- stage exchange arthroplasty protocol were finally included. ences between surgeons with respect to the approach chosen Of these, 53.8% were females; average patient age was were analysed, with a p value of 0.114 (no statistically sig- 71.5 ± 8.2 years. Comorbidities were common among the nificant differences). Regarding TTO-related complications, study population: 61.5% (32/52) were classified ASA III, we found no cases of non-union, tibial fracture, TTO frac- 50% (26/52) were McPherson Type B, and 25% (13/52) had ture or TTO displacement. In cases with repeated sequential 3 to 5 points on CCI. In addition, 19.2% (10/52) had a PJI TTO, osteotomy healing was uneventful in both stages of on a revision prosthesis, and 11.5% (6/52) were relapsed treatment. Interestingly, all patients with skin necrosis after cases following previous unsuccessful two-stage replace- the first stage (9.6%; 5/52) had been treated with an EMP ment attempts. Patient characteristics are detailed in Table 1. approach (p value 0.052). In this series, 88.5% (46/52) of the spacers implanted As principal end-point of our study, after a mean follow- were dynamic; 11.5% (6/52) were static. In 56.5% (26/46) of up of 46.2 months (range, 13.0–113.5 months), the over- the dynamic spacers, a hand-made stem was added (Table 2). all infection control rate was 90.4% (47/52), following our Spacer dislocations were detected in two dynamic-spacer stringent infection control criteria. On univariate analysis, a 13 European Journal of Orthopaedic Surgery & Traumatology Table 1  Demographics, comorbidities and infection characteristics of the 52 patients Variables All patients N = 52 (100%) Success N = 47 (90.4%) Failure N = 5 (9.6%) p Age, years; mean (IQR range) 71.5 (69.2–73.7) 71.7 (69.2–74.2) 69.2 (66.5–71.9) 0.121 Sex, male/female 24 (46.2)/28(53.8) 21 (44.7)/26(55.3) 3 (60)/2 (40) 0.352 Diabetes mellitus 17 (32.6) 15 (31.9) 2 (40) 1 Smoking 1 (1.9) 1 (2.1) 0 1 Obesity 10 (19.2) 8 (17) 2 (40) 0.242 Alcoholism 1 (1.9) 1 (2.1) 0 1 Malignant neoplasm 8 (15.4) 7 (14.9) 1 (20) 1 Arthritis 4 (7.7) 4 (8.5) 0 1 Cirrhosis 1 (1.9) 1 (2.1) 0 1 Coagulation problems 7 (13.5) 6 (12.8) 1 (20) 0.53 Charlson comorbidity index ≤2 33 (63.5) 30 (63.8) 3 (60) 0.795 3–5 13 (25) 11 (23.4) 2 (40) 6–8 5 (9.6) 5 (10.6) 0 ≥9 1 (1.9) 1 (2.1) 0 ASA scale II 19 (36.5) 16 (34) 3 (60) 0.411 III 32 (61.5) 30 (63.8) 2 (40) IV 1 (1.9) 1 (2.1) 0 McPherson Type A 22 (42.3) 20 (42.6) 2 (40) 1 Type B 26 (50) 23 (48.9) 3 (60) Type C 4 (7.7) 4 (8.5) 0 Infection scenario type Revision prosthetic infection 10 (19.2) 9 (19.1) 1 (20) 0.879 Primary prosthetic infection 31 (59.6) 28 (59.6) 3 (60) Primary prosthesis with previous failed DAIR 5 (9.6) 5 (10.6) 0 Relapse of previous replacement due to infection 6 (11.5) 5 (10.6) 1 (20) Number of previous replacement due to infection failed attempts No previous failed attempts 46 (88.5) 42 (89.4) 4 (80) 0.473 One previous failed attempt 6 (11.5) 5 (10.6) 1 (20) N surgeries previous to first time; mean (IQR range) 1.9 (1.6–2.3) 1.9 (1.5–2.3) 1.8 (0.8–2.8) 0.975 TTO performed during the second stage was associated with higher than group C (76.9%), but the difference was not sta- decreased risk of treatment failure (97.1% vs. 76.5% success tistically significant (p value 0.28) (Table 3). rate; p value 0.034) (Table 2). A Kaplan–Meier curve com- paring the two types of approaches during the second stage was conducted, in order to estimate the outcome of cases Discussion with short follow-up. As showed in Fig. 5, 90% of cases approached by a TTO during the second stage are likely to In this series of chronic knee PJIs managed with a two-stage remain without recurrence of infection at 10 years’ time, strategy employing a single CMRH prosthesis during the versus 66.9% of cases approached by EMP (p value 0.04). second stage, we found an overall infection control rate Overall, 95.2% of the patients who received repeated of 90.4% (47/52) after a mean follow-up of 46.2 months. sequential TTO (Group A) were free of infection at the end Sequential repeated TTO has been proven superior in this of follow-up, compared to 76.9% success when a TTO was scenario, showing a tendency toward better infection control not performed (Group C) (p value 0.28). We observed that (95.2% vs 76.9% success rate; p value 0.28). We identified groups A and B had a similar infection control rate (95.2% a TTO approach in the second stage as a factor for better and 94.4%, respectively). In both cases, the rate was clearly outcomes (97.1% vs 76.5%; p value: 0.034). 13 European Journal of Orthopaedic Surgery & Traumatology Table 2  Univariate analysis Variables All patients Success Failure p of all variables investigated as N = 52 (100%) N = 47 N=5 predictors of failure in two- (90.4%) (9.6%) stage reimplantation Spacer type Premade Vancomycin-Gentamicin with stem 26 (50) 24 (51.1) 2 (40) 0.829 Premade Vancomycin-Gentamicin without stem 19 (36.5) 16 (34) 3 (60) Premade Gentamicin 1 (1.9) 1 (2.1) 0 Self-made static spacer 6 (11.5) 6 (12.8) 0 PJI-causing microorganisms Gram positive 27 (51.9) 24 (51.1) 3 (60) 0.402 Gram negative 11 (21.2) 11 (23.4) 0 Anaerobe 10 (19.2) 10 (21.3) 0 Fungus 0 0 0 Polymicrobial 8 (15.4) 8 (17) 0 1 First stage approach EMP 27 (51.9) 24 (51.1) 3 (60) 1 TTO 25 (48.1) 23 (48.9) 2 (40) Second stage approach EMP 17 (32.7) 13 (27.7) 4 (80) 0.034 TTO 35 (67.3) 34 (72.3) 1 (20) Type of failure Infection relapse (same bacteria) 1 (1.9) – 1 (20) – Superinfection (different bacteria) 4 (7.7) – 4 (80) – Kept the prosthesis at the end of the follow up 48 (92.3) 47 (100) 1 (20) < 0.001 EMP extensile medial parapatellar, TTO tibial tubercle osteotomy Bold value indicates statistically significant p-values < 0.05 There is paucity of data regarding the results of TTO in Table 3  Infection eradication results based on TTO timing the setting of infected TKA [13, 23–25]. A classical criti- Groups All patients Success Failure N = 5 p cism of the technique in a septic scenario is the concern that N = 52 N = 47 (9.6%) (100%) (90.4%) it may lead to higher rates of complications including bony non-union, TTO-fragment fracture or proximal migration A–2 osteoto- 21 (40.4) 20 (95.2) 1 (4.8) 0.28 than are reported in a non-infected scenario. According to mies our data, TTO in a septic TKA is safe and reproducible. It B–1 osteotomy 18 (34.6) 17 (94.4) 1 (5.6) is noteworthy that in our series no TTO-related complica- C–0 osteotomies 13 (25) 10 (76.9) 3 (23.1) tions were found, and the union rate at final follow-up was 100%—regardless of the number of TTOs performed dur- ing the process. The risk of complications associated with TTO is a well-established technique for optimizing joint sequential repeated TTO during two-stage revision due to visualization and protecting the extensor mechanism. It infection has been poorly studied [9, 12, 24]. To the best of has yielded favourable clinical results in most published our knowledge, the only investigation specifically addressing series [9, 23, 24]. In a septic scenario, TTO allows a better the performance of sequential repeated osteotomy in the sep- approach to the lateral and posterior areas of the knee, which tic arena is the series of 13 patients reported by Choi et al. are otherwise difficult to access. In addition, a properly per- [26]. In that series the authors found radiographically con- formed TTO allows maintenance of lateral soft tissues and firmed bony union in all cases. Proximal migration occurred vascular supply to the osteotomized fragment, and is less in three of their cases; a partial proximal avulsion fracture traumatic to the surrounding soft tissues [12]. The result of the osteotomy segment occurred in one case, following of such a tissue-friendly approach is demonstrated by our the second stage. data, in which the skin necrosis rate is significantly higher As primary end point in our series of chronic knee PJIs (9.6% vs 0%; p value 0.052) among cases approached with managed with a two-stage strategy using a CMRH pros- a standard EMP as compared to TTO. thesis, we found an overall infection control rate of 90.4% 13 European Journal of Orthopaedic Surgery & Traumatology Fig. 5  Kaplan–Meier curve. Probability of infection control depending on approach during second stage (47/52 patients) after a mean follow-up of 46.2 months. This our mean follow-up was significantly shorter than that of is especially significant when one considers the average Bruni D et al. [27]; 46.2 months versus 144 months, respec- complexity of our cases (61.5% ASA III, 50% McPherson tively. To amend that to some extent, we analysed the prob- Type B). The influence of TTO on infection control rates has ability of remaining without recurrence of infection with a been but rarely reported in the literature [27]. Kaplan–Meier estimate (Fig. 5), finding that the infection The rationale for this approach is based on the belief that control rate at 10 years’ time would likely be 90% for cases TTO allows superior access to the infected knee, permit- approached by a TTO in the second stage, versus 66.9% in ting much more adequate debridement. This is especially patients approached by EMP (p value 0.04). important in complex cases with multiple previous failed The current study did not find a statistically significant interventions, where stiffness and scar tissue make proper difference in relapse rates between the group using sequen- access to the joint arduous. One of the few investigations tial repeated TTO (Group A) and the non-osteotomy group on the subject is a prospective study by Bruni D et al.[27], (Group C). The incidence of infection control (76.9% for the in which they investigated the reinfection rate in knee PJI non-osteotomy group and 95.2% for the sequential repeated patients treated with two-stage exchange arthroplasty using TTO group), limits powering such a study. However, the either a TTO or a quadriceps snip (QS) for exposure at the 18.3% improvement in infection control suggests that use of time of reimplantation. In their series, they found no dif- sequential repeated TTO merits further study. ference in reinfection rates between groups. As a criticism, We recognize the limitations of our study. Designed as it should be noted that they mentioned no use of validated a retrospective non-randomized analysis, all data was gath- criteria for success. Conversely, our results support this idea: ered from medical records; being the inability to obtain all performing a TTO in the second stage (sequential or iso- relevant information one of the drawbacks of our study. It is lated) was identified as a factor for superior infection con- a single-institution study, hence limiting the generalization trol outcomes (97.1% vs. 76.5%; p value 0.034). However, of our results. Three different surgeons operated and treated 13 European Journal of Orthopaedic Surgery & Traumatology the study’s patients, which increases variability; however, all Data availability The data that support the findings of this study are of them followed the same pre-established protocol, assisted available from the corresponding author (Marta Pérez), upon reason- able request. each other in performing the procedures, and are specialised in treating musculoskeletal infections. In addition, differ- Code availability Not applicable. ences between surgeons in terms of approach chosen were assessed without finding statistically significant differences. Declarations Nevertheless, the selected approach in each specific case Conflict of interest All Authors: None of the authors received pay- could establish a bias. It would be logical to think that oste- ments or services, either directly or indirectly (i.e., via his or her insti- otomy has been chosen in the most complex cases (selection tution), from a third party in support of any aspect of this work. One of bias), but the fact of obtaining better results in TTO cases the authors (Pablo S. Corona) has done paid speaking engagements at validates the usefulness of this approach in complex cases scientific conferences during the thirty-six months prior to submission of this work, to an entity in the biomedical arena (Tecres SpA, Som- of infection. Other limitations that should be considered are macampagna–VR, Italy and Waldemar Link GmbH & Co.; Germany) the sample size and follow-up period. However, both these whose products have been mentioned in the article. The author does parameters were comparable or superior to previously pub- not have any other conflict of interest with said companies. No author lished studies. Although the limited sample size impeded has had any other relationships, or has engaged in any other activities that could be perceived to influence or have the potential to influence a solid multivariable regression analysis, in the best of our what is written in this work. knowledge this is the largest series addressing the perfor- mance of sequential repeated osteotomy in the septic arena. Ethical approval The Drug and Clinical Research Ethics Commit- Because of these limitations, our results should be inter- tee of Vall d’Hebron University Hospital approved this study (date: 13/11/2020, reference number: PR(ATR)283/2020). preted with caution; studies with a longer follow-up period and larger patient bases are needed. Consent to participate Informed consent was obtained from all indi- vidual participants included in the study. Consent to publish Consent to publish was received from all individual participants included in the study. Conclusions Open Access This article is licensed under a Creative Commons Attri- The results of the current study suggest that a TTO (repeated bution 4.0 International License, which permits use, sharing, adapta- or isolated) in a two-stage exchange strategy is a reasonable tion, distribution and reproduction in any medium or format, as long option and offers a high rate of infection control and low as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes complication rate in complex cases of knee PJI. were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated Acknowledgements We wish to thank Russell Williams of Roundly- otherwise in a credit line to the material. If material is not included in Worded.com for his editorial recommendations. We further wish to the article's Creative Commons licence and your intended use is not thank our entire multidisciplinary team, including Dr. Lluís Carrera, permitted by statutory regulation or exceeds the permitted use, you will member of the Septic and Reconstructive Surgery Unit; Dr. Carles need to obtain permission directly from the copyright holder. To view a Pigrau and Dr. Dolors Rodríguez-Pardo, members of the Infectious copy of this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. Diseases Department; Dr. Mayli Lung, member of the Microbiology Department; Dr. Jordi Serracanta and Dr. Jordi Aguilera, members of the Plastic Surgery Department, and Dr. Juan Carlos Juarez, a member of our centre’s Pharmacy Department. I would also like to acknowledge the inestimable help of Rosa Fraile Soriano, operating room nurse spe- References cialized in septic pathology. Without her help, it would be far more dif- ficult to operate on patients of this type. We want to acknowledge that this study has been carried out as part of the Department of Surgery and 1. Bozic KJ, Kurtz SM, Lau E, Ong K, Chiu V, Vail TP et al (2010) Morphological Sciences thesis program of the Universitat Autònoma The epidemiology of revision total knee arthroplasty in the de Barcelona (UAB). Finally, we want to express our gratitude to the United States. Clin Orthop 468(1):45–51. https://d​ oi.o​ rg/1​ 0.1​ 007/​ MBA Institute for their help and methodological support in the realiza- s11999-​009-​0945-0 tion of this study. 2. Lichstein P, Gehrke T, Lombardi A, Romano C, Stockley I, Babis G et al (2014) One-stage versus two-stage exchange. J Orthop Res Author contributions All authors contributed to the study conception 32(Suppl 1):S141-146. https://​doi.​org/​10.​1002/​jor.​22558 and design. Material preparation and data collection were performed 3. Insall JN (1982) Infection in total knee arthroplasty. Instr Course by PSC, MP and OP. The first draft of the manuscript was written by Lect 31:42–48 PSC and MP and all authors commented on previous versions of the 4. Corró S, Vicente M, Rodríguez-Pardo D, Pigrau C, Lung M, manuscript. All authors read and approved the final manuscript. 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