Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 https://doi.org/10.1007/s00167-023-07547-0 KNEE Good long‑term patients reported outcomes, return‑to‑work and return‑to‑sport rate and survivorship after posterior cruciate ligament (PCL)‑based multiligament knee injuries (MLKI) with posteromedial corner tears as significant risk factor for failure Nicola Pizza1,2 · Stefano Di Paolo2 · Alberto Grassi3 · Anna Pagano2 · Marianna Viotto2 · Giacomo Dal Fabbro2 · Piero Agostinone2 · Gian Andrea Lucidi2 · Juan Carlos Monllau1 · Stefano Zaffagnini2,3 Received: 7 May 2023 / Accepted: 9 August 2023 / Published online: 5 September 2023 © The Author(s) 2023 Abstract Purpose To assess the survival rate and associated risk factors of a wide cohort of patient’s underwent surgical treatment for posterior cruciate ligament (PCL)-based multiligament knee injury (MLKI) at long-term follow-up and to investigate the long-term patient’s reported outcomes (PROMS) and functional activity. Methods All cases of PCL-based MLKI performed at one single sport-medicine institution were extracted and patient’s with a minimum 2 years of follow-up included. VAS, Lysholm, KOOS, Tegner Activity level scores, the incidence and time of return to sport (RTS) and return to work (RTW) were collected before, after surgery and at final follow-up. A multivariate logistic regression was performed to investigate the outcomes associated with the patient’s acceptable symptoms state (PASS) for each sub-score of the KOOS. The Kaplan–Meier method with surgical failure (re-operation to one of the reconstructed ligaments) as endpoint was used to perform the survivorship analysis for the entire cohort. Results Forty-two patients were included and evaluated at an average of 10 years. All PROMS significantly improved from pre- to post-surgery (range ηp2 0.21–0.43, p < 0.05) except for the Tegner score which significantly improved from pre-surgery and to final follow-up (ηp2 = 0.67, p < 0.001). RTW was achieved in the 95.2% after 2.4 ± 1.9 months. RTS was achieved in 78.6% after 6.7 ± 5.0 months. The higher number of surgeries were the significant negative predictors of PASS for the KOOS sub-scales Sport (p = 0.040) and Quality of Life (p = 0.046), while the presence of meniscal lesions was a significant nega- tive predictor of PASS only for the KOOS sub-scale of Sport (p = 0.003). Six patients (14.3%) underwent reoperation and were considered as surgical failures. The global survivorship was 95.2%, 92.6%, 87.1%, and 74.7% at 2, 5, 12, and 15 years, respectively. The survivorship in patient undergoing PMC reconstruction surgery was significantly lower (p = 0.004; HR 7.1) compared to patients without a PMC lesion. Conclusion Good-to-excellent PROMS could be obtained and maintained at long-term follow-up after surgery, with the higher number of surgeries and meniscal lesions as significant negative predictors of the PASS. Moreover, the presence of a PMC lesion significantly increases the risk of the PCL reconstruction failure. Level of evidence III. Keywords PCL-based MLKI · PMC · PROMS · Failure · Survivorship Introduction of autonomously reduced knee dislocation [17, 22]. MLKI are defined as the lesion of at least two of the four main liga- Multiple ligament knee injuries (MLKI) are as rare as pos- mentous structures of the knee, and its classification follows sibly devastating condition. Even though account for only the one proposed by Schenk et al. [24] According to Fanelli, 0.02–0.2% of all orthopedic injuries the real incidence could the isolated lesions of the posterior cruciate ligament (PCL) be overlooked due to the subtle diagnosis and the occurrence are rare respect to its association with other knee ligaments injuries defining the so-called PCL-based multiligament knee injuries which account for the 96% of cases [5]. The Extended author information available on the last page of the article 13 Vol:.(1234567890) Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 5019 association of structures involved is extremely variable due Statistical analysis to injury mechanism, patient’s characteristics, and knee anatomy itself [2, 6, 10] and this account for many different The sample size was determined according to an a-priori scenarios to be managed by the surgeon. Of these, bi-cruci- power analysis in G*Power (v3.1, Brunsbüttel, Germany). ate (Anterior Cruciate Ligament—ACL; Posterior Cruciate The calculation was based on a repeated measure ANOVA Ligament—PCL) injuries are often associated with medial considering the three time frames (pre-surgery, post-surgery, and/or lateral structures involvement representing one of the final follow-up) for PROMS. A within group variance of 20 most severe conditions. So far, the best solution to improve points in PROMS (Lysholm score) emerged from literature clinical outcomes is represented by the surgical intervention [12, 14]. Hypothesizing a conservative variance explained of the torn ligaments. However, several issues are still pre- by the time effect of 1 point, an effect size of 0.22 emerged. sent regarding different topics such as the timing of surgery, Considering an alfa = 0.05 and a power of 0.8, the minimum the use of allograft or autograft, the number of procedures sample size required was identified in 34 patients. needed, if repair or reconstruct and which ligament recon- Descriptive statistics (mean, standard deviation, confi- struct first. Another crucial topic to be investigated is the dence intervals) were collected for each score at each time likelihood for patients to undergo further surgical procedures frame. The ANOVA was used to investigate the improve- and which are the correlated risk factors. Moreover, if good ment in PROMS after surgery. A multivariate logistic regres- outcomes have been reported in the short-term there is a lack sion was performed to investigate the outcomes associated of studies investigating the outcomes of such procedures in with the patient’s acceptable symptoms state (PASS) for the long-term. each sub-score of the KOOS. Hence, the purpose of the present study was to assess the Survival analysis was performed via the Kaplan–Meier survival rate and associated risk factors of a wide cohort method with surgical failure (re-operation to one of the of patient’s underwent surgical treatment for PCL-based reconstructed ligaments) as endpoint. The mean estimated MLKI at long-term follow-up and to investigate the long- survival time was calculated for the entire cohort, further- term patient’s reported outcomes (PROMS) and functional more, the survivorship of ACL-PCL-PMC, ACL-PCL-PLC, activity. and if a PMC lesion was present, were compared. The log- The clinical relevance of this study derives from the rank test with hazard ratio was calculated, with p < 0.05 set deepening of the knowledge into the MLKI which can help as level of statistical significance. A logistic regression was the surgeon to set patient’s expectations in these complex also performed by using sex, BMI (≤ 25 vs > 25), age at sur- scenarios. gery, limb, presence of cartilage lesions, diabetes, smoke, meniscal lesion as independent variables. Material and methods Results All procedures described in this study were performed in A total of 42 consecutive patients (39 males and 3 accordance with the ethical standards of the 1964 Helsinki females) were included and evaluated at an average of declaration and its later amendments and Rizzoli Orthopedic 10 years with minimum 2 years follow-up (Table 1). Institute Ethic Committee approval was obtained (Internal Protocol CE AVEC: 147/2021/Oss/IOR). All patients signed an informed consent form before recruitment. No external funding was received for the initiation or completion of this Table 1  Demographic data of patient’s included study. Demographic data The institutional database was retrospectively searched Follow-up time, years 9.6 ± 5.6 [2–28] for patients who underwent isolated and/or combined PCL Age at surgery, years 31.4 ± 12.2 [13–59] reconstruction between January 2000 and December 2019. From trauma to surgery, years 3.3 ± 7.3 [0.1–35] Medical charts were reviewed to collect patients’ infor- Sex, M/F 39/3 mation, anamnesis, and surgical data. All the patients Limb, R/S 23/19 were contacted to assess the occurrence of further surgical BMI, ≤ 25 / > 25 28/14 procedures. Diabetes, Y/N 4/38 The VAS, Lysholm, KOOS, and Tegner Activity level Smoke, Y/N 14/28 scores were collected for each patient before, after surgery Meniscal lesion, Y/N 10/32 and at final follow-up. The incidence and time of return to Cartilage lesion, Y/N 7/35 sport (RTS) and return to work (RTW) were collected. 13 5020 Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 Table 2  Clinical outcomes pre- Clinical outcomes injury, pre-surgery, post-surgery Score Pre-injury Pre-surgery Post-surgery Final follow-up ηp2 p value a a VAS 43.5 ± 26.3 28.1 ± 23.3 20.9 ± 21.5 0.43 < 0.001 Lysholm 73.0 ± 18.9 76.8 ± 14.3 82.3 ± 8.7 0.20 n.s KOOS–ADL 57.7 ± 12.8 62.9 ± 11.9a 64.9 ± 11.7a 0.30 0.002 KOOS–Pain 72.5 ± 24.3 79.6 ± 18.0 83.5 ± 16.9a 0.21 0.019 KOOS–Function 78.0 ± 26.0 85.3 ± 18.8 89.5 ± 16.5a 0.21 0.017 KOOS–Sport 54.0 ± 32.6 61.8 ± 29.2 69.0 ± 27.0 0.22 0.015 KOOS–QoL 47.7 ± 31.3 57.8 ± 26.7 63.4 ± 26.2 0.28 0.004 Tegner 8 [0–10] 2.5 [0–10] 5 [0–10] 5 [0–10]a,b 0.67 < 0.001 a Difference from pre-surgery b Difference from post-surgery 11 patients underwent isolated PCL-reconstruction Table 3  Surgical failure according to the surgical intervention (26%), 2 ACL + PCL (4.7%), 9 PCL + PMC (21%), 6 Surgical failure according to the surgical intervention PCL + PLC (14.2%), 7 PCL + ACL + PLC (16.7%) and 7 PCL + ACL + PMC (16.7%). Surgery Surgical failure Total % of number of surgical No Yes patients failure Clinical outcomes PCL 11 0 11 0.0 ACL + PCL 1 1 (PCL) 2 50.0 A significant improvement in all PROMS was noted from PCL + PMC 8 1 (PCL) 9 11.1 pre- to post-surgery (range ηp2 0.21–0.43, p < 0.05) except PCL + PLC 5 1 (PCL) 6 16.7 for the Tegner score. No differences were noted between PCL + ACL + PLC 7 0 7 0.0 the post-op and the final follow-up (n.s.) (Table 2). The PCL + ACL + PMC 4 3 (PCL/PMC/ 7 42.9 PCL + PMC) pre-injury Tegner score was never reached after surgery, Total 36 6 42 14.3 but a significant improvement was noted between the pre- surgery and the final follow-up (η p2 = 0.67, p < 0.001) (Table 2). The RTW was achieved in the 95.2% (40/42) after 2.4 ± 1.9 months and RTS was achieved in 78.6% (33/42) after 6.7 ± 5.0 months. The higher number of sur- geries were the significant negative predictors of PASS for the KOOS sub-scales Sport (p = 0.040) and Quality of Life (p = 0.046), while the presence of meniscal lesions was a significant negative predictor of PASS only for the KOOS sub-scale of Sport (p = 0.003). Survivorship analysis Six patients (14.3%) underwent reoperation and were con- sidered as surgical failures (Table 3). The global survivor- ship was 95.2%, 92.6%, 87.1%, and 74.7% at 2, 5, 12, and 15 years, respectively (Fig. 1). The survivorship in patient undergoing PMC reconstruction surgery was significantly lower (p = 0.004; HR 7.1) compared to patients without a PMC lesion (Fig. 2). No survival differences were found Fig. 1  Global survivorship of PCL-based multiligaments between the ACL-PCL-PMC and the ACL-PCL-PLC 13 Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 5021 Fig. 2  Surgical failure of PCL- based multiligaments (n.s.). No significant outcome interaction emerged from at the time of surgery and the higher number of surgeries. In the multiple regression analysis (n.s.). authors opinion these two factors are extremely correlated. It is well established that objective instability not only influ- ence patient’s perception of the knee, but more importantly Discussion affects the meniscal and cartilage condition with a gener- ally reported higher incidence of meniscal lesion in chronic The most important finding of the present study was that ligaments deficiency scenarios [16]. Also, Moathse et al. in good-to-excellent PROMS could be obtained and maintained a prospective review of 303 patients reported about 40% of at long-term follow-up after PCL-MLKI, with the higher meniscal tears and a higher incidence of cartilage injury number of surgeries and meniscal lesions as significant in chronic scenarios [13, 17]. Hence, this finding seems to negative predictors of the PASS. Moreover, the presence suggest that an early and not staged surgical management of a PMC lesion significantly increases the risk of the PCL of such injuries could be a better solution, even though this reconstruction failure. topic is still controversial [7, 15, 19–21]. Focusing on the Clinical outcomes after multiligament knee injury are dif- return to previous activity we found different scenarios. ficult to be compared, due to the low incidence of the pathol- The possibility to RTW was well achieved by the whole ogy, the heterogeneity of the lesions and the different possi- population with a rate of 95% after almost 2 months, as also ble treatments. What is somehow commonly accepted is that found by Worley et al.[26] Regarding the RTS there was a the surgical treatment of these conditions is the best solution. significant improvement from the pre-operative to the post- Ritcher et al., in fact, compared a group of patients which operative Tegner level which remained stable till the last underwent surgical treatment of MLKI with patients which follow-up, even though none reached the pre-injury level. were treated only with rehabilitation. The last reported lower In authors opinion, these findings could be explained by the clinical outcomes in terms of knee function and return sport age of the population analyzed (30 years old average). This and to work [23]. Also, Wong et al. reported better outcomes age range, in fact, usually need to rapidly return to work, but in terms of IKDC and subjective instability for patients regarding the RTS, on the other hand, the low rate of return underwent operative treatment [25]. In the present series to the pre-injury level highlights the complexity and possibly we noted that patients could be able to reach significantly life-changing burden of these injuries, since sport participa- better outcomes post-operatively and this result remained tion is perceived as an important aspect of the life, as dem- stable throughout the years. Interestingly the outcomes onstrated by a rate of RTS of almost 80%, even at a lower were significantly influenced by the meniscal status found level. These findings are in line with other researchers [1, 4, 13 5022 Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 7, 17]. Moathse et al. [17] reported in the same age group insertion of the superficial MCL, the deep MCL blended similar rates of RTW and RTS as also Godin et al. which with the capsule and thin width and different orientation of analyzed older adolescent population (17 years old average) the POL makes its repair and reconstruction difficult to be reporting an improvement of the Tegner from pre- to post- performed with a usually not avoidable grade of residual operation, but also concluding that such injuries could lead laxity which could overload the PCL reconstructed and so to impaired function [7]. Also, in a recent systematic review leading to its failure [3, 18]. Everhart et al. highlighted a high RTW rate (88.4%) but a The present study has some limitations. First the rela- low RTS at any level (53.6%) and even lower if considering tively low number of patients included, in fact, some data high level of sports (22–33%) [4]. Another crucial aspect could have reached the statistical significance if analyzed that influenced the RTS findings were the number of surger- in a wider cohort. Second, the difficult generalizability of ies and meniscal lesions which negatively affected the Sport these findings is difficult. Third the retrospective nature of KOOS sub-scale. Meniscal tears are highly represented in the study. However, the present case-series presented the MLKI [11], reported in almost the 30% of patients in the results of number of subjects in line with the wideness present series (Table 1), and their detrimental role is in line of other cohort studies on the same topic. In addition, to with King et al. findings, which reported significant lower authors knowledge, this is the first study that indented to clinical outcomes at 6 years follow-up in 121 patients with evaluate the possible factors influencing the PASS in such cartilage and combined meniscal tears [12]. injuries, performed a survival analysis with the risk fac- These two aspects could have influenced the PASS tors associated and presented results at such long follow-up from different sides. One is the need of a long rehabilita- (average 11.9 years). Moreover, given the variety and rar- tion process after every surgical intervention, usually from ity of presentation of these injuries, designing high level 6 to 12 months for a safe return to impact activities. From of evidence trials is difficult, and the contribution of not- the other side the presence of meniscal lesions could have high-level-evidence data is important. Undoubtedly, the need driven the patients to a more conservative behavior in terms of multicentric study of dramatic usefulness as suggested of sport participations. Interestingly the sub-scale of sports by Hankins et al. [8]. Despite these limitations the authors and quality of life were influenced by the same factors, fur- believes that the clinical relevance of this study derives from therly supporting the idea that the quality of life is somehow the deepening of the knowledge into the MLKI; in particu- influenced by sport activity. To authors knowledge this is the lar, regarding the need of further surgical major procedures first study which investigated the possible factors influencing which can help the surgeon to set patient’s expectations in the PASS in MLKI patients. these complex scenarios. Focusing on the survivorship analysis, another notable The clinical relevance of this study derives from the finding of the present study is that patients who presented a deepening of the knowledge into the MLKI; from one side, PMC lesion were burdened by a sevenfold increased risk of regarding the risk of further ligament revision surgery in failure of the PCL reconstruction. Overall, more than 92% of case of medial-sided injuries and from the other side, to reconstructed knees still were revision-free at 5 years follow- set patient’s expectations regarding long-term outcomes and up, and only after the first decades these patients underwent return-to-sport rate which even if high was never at pre- a revision of at least one ligament previously reconstructed, injury level. with a relevant drop at 15 years. Different authors have highlighted a higher failure rate when repair of the cruciate and collateral ligaments is performed, thus suggesting for Conclusions anatomic reconstruction of the torn ligaments [7, 12, 14]. In the present study it is not possible to drive such conclu- Good-to-excellent PROMS could be obtained and main- sion since the cohort is variegated and not always so-called tained at long-term follow-up after surgery, with the higher anatomic reconstructions have been performed. However, its number of surgeries and meniscal lesions as significant authors opinion, and these findings seems support this, that negative predictors of the PASS. Moreover, the presence in MLKI surgeries scenarios also repairs and non-anatomic of a PMC lesion significantly increases the risk of the PCL reconstruction could drive to excellent outcomes as also sug- reconstruction failure. gested by Hanley et al. [9]. Interestingly in the present series there was a significantly lower survivorship for medial-sided injuries. Also, King et al. [12] in a cohort of 56 patients Funding Open Access Funding provided by Universitat Autonoma de at 6-year follow-up reported poorer outcomes in patients Barcelona. underwent medial sided injuries. This could be explained by Data availability The authors declare that the data supporting the find- the higher incidence of such injuries in MLKI scenarios [7] ings of this study are available within the article, additional data are and by the anatomy of the PMC itself. In fact the wide tibial available from the corresponding author upon request. 13 Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 5023 Declarations 8. Hankins DA, Fletcher IE, Prieto F, Ockuly AC, Myers OB, Treme GP, Veitch AJ, Wascher DC, Schenck RC, Richter DL (2019) Conflict of interest Each author certifies that he or she has no com- Critical evaluation of the methodologic quality of the top 50 cited mercial associations that might pose a conflict of interest in connection articles relating to knee dislocation and multiligamentous knee with the submitted article. injury. Orthop J Sports Med 7(11):2325967119880505 9. Hanley JM, Anthony CA, DeMik D, Glass N, Amendola A, Wolf Ethical approval All procedures described in this study were per- BR, Bollier M (2017) Patient-reported outcomes after multiliga- formed in accordance with the ethical standards of the 1964 Helsinki ment knee injury: MCL repair versus reconstruction. Orthop J declaration and its later amendments and Rizzoli Orthopedic Institute Sports Med 5(3):2325967117694818 Ethic Committee approval was obtained (Internal Protocol CE AVEC: 10. Hua X, Tao H, Fang W, Tang J (2016) Single-stage in situ suture 147/2021/Oss/IOR). repair of multiple-ligament knee injury: a retrospective study of 17 patients (18 knees). BMC Musculoskelet Disord 17:41 Consent to participate All patients signed an informed consent form 11. Kim SH, Park Y-B, Kim B-S, Lee D-H, Pujol N (2021) Inci- approved by the Ethic Committee before recruitment. dence of associated lesions of multiligament knee injuries: a systematic review and meta-analysis. Orthop J Sports Med Open Access This article is licensed under a Creative Commons Attri- 9(6):23259671211010410 bution 4.0 International License, which permits use, sharing, adapta- 12. King AH, Krych AJ, Prince MR, Pareek A, Stuart MJ, Levy BA tion, distribution and reproduction in any medium or format, as long (2016) Surgical outcomes of medial versus lateral multiligament- as you give appropriate credit to the original author(s) and the source, injured. Dislocated Knees Arthrosc 32(9):1814–1819 provide a link to the Creative Commons licence, and indicate if changes 13. Krych AJ, Sousa PL, King AH, Engasser WM, Stuart MJ, were made. The images or other third party material in this article are Levy BA (2015) Meniscal tears and articular cartilage damage included in the article's Creative Commons licence, unless indicated in the dislocated knee. Knee Surg Sports Traumatol Arthrosc otherwise in a credit line to the material. If material is not included in 23(10):3019–3025 the article's Creative Commons licence and your intended use is not 14. Levy BA, Dajani KA, Morgan JA, Shah JP, Dahm DL, Stuart MJ permitted by statutory regulation or exceeds the permitted use, you will (2010) Repair versus reconstruction of the fibular collateral liga- need to obtain permission directly from the copyright holder. To view a ment and posterolateral corner in the multiligament-injured knee. copy of this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. Am J Sports Med 38(4):804–809 15. Levy BA, Dajani KA, Whelan DB, Stannard JP, Fanelli GC, Stuart MJ, Boyd JL, MacDonald PA, Marx RG (2009) Decision making in the multiligament-injured knee: an evidence-based systematic References review. Arthroscopy 25(4):430–438 16. Mehl J, Otto A, Baldino JB, Achtnich A, Akoto R, Imhoff AB, Scheffler S, Petersen W (2019) The ACL-deficient knee and the 1. Blokland D, van Ooij B, Reilingh ML, Wolterbeek N, Zijl JAC prevalence of meniscus and cartilage lesions: a systematic review (2021) Low rate of return to pre-injury level of sports after multi- and meta-analysis (CRD42017076897). Arch Orthop Trauma ligament knee injury—functional outcomes after MLKI. Knee Surg 139(6):819–841 33:65–72 17. Moatshe G, Dornan GJ, Løken S, Ludvigsen TC, LaPrade RF, 2. Bonanzinga T, Zaffagnini S, Grassi A, Marcheggiani Muccioli Engebretsen L (2017) Demographics and injuries associated with GM, Neri MP, Marcacci M (2014) Management of combined knee dislocation: a prospective review of 303 patients. Orthop J anterior cruciate ligament-posterolateral corner tears: a systematic Sports Med 5(5):2325967117706521 review. Am J Sports Med 42(6):1496–1503 18. Moatshe G, Vap AR, Getgood A, LaPrade RF, Engebretsen L 3. Chahla J, Kunze KN, LaPrade RF, Getgood A, Cohen M, Gelber (2020) Medial-sided injuries in the multiple ligament knee injury. P, Barenius B, Pujol N, Leyes M, Akoto R, Fritsch B, Margheri- J Knee Surg 33(5):431–439 tini F, Rips L, Kautzner J, Duthon V, Togninalli D, Giacamo Z, 19. Mojica ES, Bi AS, Vasavada K, Moran J, Buzin S, Kahan J, Alaia Graveleau N, Zaffagnini S, Engbretsen L, Lind M, Maestu R, Von EF, Jazrawi LM, Medvecky MJ, Alaia MJ (2023) Poorer func- Bormann R, Brown C, Villascusa S, Monllau JC, Ferrer G, Men- tional outcomes in patients with multi-ligamentous knee injury etrey J, Hantes M, Parker D, Lording T, Samuelsson K, Weiler with concomitant patellar tendon ruptures at 5 years follow-up. A, Uchida S, Frosch KH, Robinson J (2021) The posteromedial Knee Surg Sports Traumatol Arthrosc 31(1):325–331 corner of the knee: an international expert consensus statement on 20. Mook WR, Miller MD, Diduch DR, Hertel J, Boachie-Adjei Y, diagnosis, classification, treatment, and rehabilitation. Knee Surg Hart JM (2009) Multiple-ligament knee injuries: a systematic Sports Traumatol Arthrosc 29(9):2976–2986 review of the timing of operative intervention and postoperative 4. Everhart JS, Du A, Chalasani R, Kirven JC, Magnussen RA, rehabilitation. J Bone Joint Surg Am 91(12):2946–2957 Flanigan DC (2018) Return to work or sport after multiligament 21. Mortazavi SMJ, Kaseb MH, Maleki RG, Razzaghof M, Noori knee injury: a systematic review of 21 studies and 524 patients. A, Rezaee R (2022) The functional outcomes of delayed surgical Arthroscopy 34(5):1708–1716 reconstruction in nonsport-induced multiligament knee injuries: 5. Fanelli GC (2019) PCL based multiple ligament knee injuries: a retrospective cohort study. J Knee Surg 35(10):1097–1105 what I have learned in 28 years. In: Fanelli GC (ed) The multiple 22. Mosquera MF, Jaramillo A, Gil R, Gonzalez Y (2020) Contro- ligament injured knee: a practical guide to management. Springer versies in acute multiligamentary knee injuries (MLKI). J Exp International Publishing, Cham, pp 3–21 Orthop 7(1):56 6. Fanelli GC, Edson CJ (2020) Combined ACL-PCL-medial and 23. Richter M, Bosch U, Wippermann B, Hofmann A, Krettek C lateral side injuries (Global Laxity). Sports Med Arthrosc Rev (2002) Comparison of surgical repair or reconstruction of the 28(3):100–109 cruciate ligaments versus nonsurgical treatment in patients with 7. Godin JA, Cinque ME, Pogorzelski J, Moatshe G, Chahla J, traumatic knee dislocations. Am J Sports Med 30(5):718–727 LaPrade RF (2017) Multiligament knee injuries in older adoles- cents: a 2-year minimum follow-up study. Orthop J Sports Med 5(9):2325967117727717 13 5024 Knee Surgery, Sports Traumatology, Arthroscopy (2023) 31:5018–5024 24. Schenck RC, Richter DL, Wascher DC (2014) Knee Dislocations. reconstruction after surgical management of multiligament knee Orthop. J Sports Med 2(5):2325967114534387 injury. J Knee Surg 35(1):72–77 25. Wong C-H, Tan J-L, Chang H-C, Khin L-W, Low C-O (2004) Knee dislocations-a retrospective study comparing operative ver- Publisher's Note Springer Nature remains neutral with regard to sus closed immobilization treatment outcomes. Knee Surg Sports jurisdictional claims in published maps and institutional affiliations. Traumatol Arthrosc 12(6):540–544 26. Worley JR, Brimmo O, Nuelle CW, Zitsch BP, Leary EV, Cook JL, Stannard JP (2022) Revision anterior cruciate ligament Authors and Affiliations Nicola Pizza1,2 · Stefano Di Paolo2 · Alberto Grassi3 · Anna Pagano2 · Marianna Viotto2 · Giacomo Dal Fabbro2 · Piero Agostinone2 · Gian Andrea Lucidi2 · Juan Carlos Monllau1 · Stefano Zaffagnini2,3 * Nicola Pizza Gian Andrea Lucidi nicola.pizza@ior.it gianandrea.lucidi@studio.unibo.it Stefano Di Paolo Juan Carlos Monllau stefano.dipaolo@ior.it jmonllau@psmar.cat Alberto Grassi Stefano Zaffagnini alberto.grassi@ior.it stefano.zaffagnini@unibo.it Anna Pagano 1 Knee and Arthroscopy Unit, ICATME, Hospital Universitari anna.pagano94@gmail.com Dexeus, Universitat Autònoma de Barcelona, Barcelona, Marianna Viotto Spain marianna.viotto@ior.it 2 Clinica Ortopedica e Traumatologica II, IRCCS Istituto Giacomo Dal Fabbro Ortopedico Rizzoli, Bologna, Italy giacomo.dalfabbro@studio.unibo.it 3 Dipartimento di Scienze Biomediche e Neuromotorie, Piero Agostinone DIBINEM, Università di Bologna, Bologna, Italy piero.agostinone@studio.unibo.it 13