International Orthopaedics (2023) 47:1213–1219 https://doi.org/10.1007/s00264-023-05712-1 ORIGINAL PAPER Three‑dimensional‑printed patient‑specific instrumentation is an accurate tool to reproduce femoral bone tunnels in multiple‑ligament knee injuries Núria Fernández‑Poch1 · Ferran Fillat‑Gomà1,2 · Laia Martínez‑Carreres1,2 · Sergi Coderch‑Navarro2 · Christian Yela‑Verdú1 · Sonia Carbó‑Cedán3 · Xavier Pelfort1 Received: 21 November 2022 / Accepted: 26 January 2023 / Published online: 17 February 2023 © The Author(s) 2023 Abstract Purpose Multiple-ligament knee reconstruction techniques often involve the creation of several bone tunnels for various reconstruction grafts. A critical step in this procedure is to avoid short tunnels or convergences among them. Currently, no specific template guide to reproduce these angulations has been reported in the literature, and the success of the technique still depends on the experience of the surgeon. The aim of this study is to analyze the accuracy and reliability of 3D-printed patient-specific instrumentation (PSI) for lateral and medial anatomical knee reconstructions. Methods Ten cadaveric knees were scanned by computed tomography (CT). Using specific computer software, anatomical femoral attachments were identified: (1) on the lateral side the lateral collateral ligament (LCL) and the popliteal tendon (PT) and (2) on the medial side the medial collateral ligament (MCL) and the posterior oblique ligament (POL). Four bone tunnels were planned for each knee, and PSI with different directions were designed as templates to reproduce the planned tunnels during surgery. Twenty 3D-printed PSI were used: ten were tailored to the medial side for reconstructing MCL and POL tunnels, and the other ten were tailored to the lateral side for reconstructing LCL and PT tunnels. Postoperative CT scans were made for each cadaveric knee. The accuracy of the use of 3D-printed PSI was assessed by superimposing post- operative CT images onto pre-operative images and analyzing the deviation of tunnels performed based on the planning, specifically the entry point and the angular deviations. Results The median entry point deviations for the tunnels were as follows: LCL tunnel, 1.88 mm (interquartile range (IQR) 2.2 mm); PT tunnel, 2.93 mm (IQR 1.17 mm); MCL tunnel, 1.93 mm (IQR 4.26 mm); and POL tunnel, 2.16 mm (IQR 2.39). The median angular deviations for the tunnels were as follows: LCL tunnel, 2.42° (IQR 6.49°); PT tunnel, 4.15° (IQR 6.68); MCL tunnel, 4.50° (IQR 6.34°); and POL tunnel, 4.69° (IQR 3.1°). No statistically significant differences were found in either the entry point or the angular deviation among the different bone tunnels. Conclusion The use of 3D-printed PSI for lateral and medial anatomical knee reconstructions provides accurate and repro- ducible results and may be a promising tool for use in clinical practice. Keywords Multiple-ligament reconstruction · Knee · Tunnels · 3D printing · Patient-specific instrumentation * Ferran Fillat‑Gomà Introduction ferran@doctorfillat.com Knee dislocation is a rare injury but has potentially devas- 1 Orthopaedics Department, Parc Taulí Hospital Universitari, tating consequences for the injured patients [1, 2]. There Institut d’Investigació I Innovació Parc Taulí I3PT, is consensus in the literature that the surgical treatment of Universitat Autònoma de Barcelona, Sabadell, Spain 2 these lesions improves clinical outcomes compared to non- 3D Surgical Planning Lab., Parc Taulí Hospital Universitari, surgical management [3–5]. In recent years, there has been Institut d’Investigació I Innovació Parc Taulí I3PT, Universitat Autònoma de Barcelona, 08208 Sabadell, Spain a progressive evolution in surgical techniques toward a more 3 anatomical reconstruction of the injured ligaments [6–9]. Radiology Department, Parc Taulí Hospital Universitari, Institut d’Investigació I Innovació Parc Taulí I3PT, Most of these studies have reported better clinical and func- Universitat Autònoma de Barcelona, Sabadell, Spain tional results if all ligament reconstructions were performed 13 Vol.:(0123456789) 1214 International Orthopaedics (2023) 47:1213–1219 in a one-step surgery [10–12]. The reconstruction of these side [25] were first identified. Then, four bone tunnels were ligaments often involves the creation of several tunnels in a planned for each knee starting from the anatomical attach- small area of the distal femur. Due to the limited bone mass, ments of the LCL, PT, MCL, and POL applying different a critical step in these procedures is to avoid short tunnels directions. Two personalized surgical guides were designed or convergences among them because this can compromise each knee to reproduce the planned tunnels during surgery: the integrity of the graft [13, 14] and may result in damage the first one for the LCL and PT and the second one for to fixation devices, poor graft fixation, or intra-operative and the MCL and POL. The direction of the tunnels was vari- post-operative femoral fractures [15–18]. Some authors have able. The design criteria to be followed in all cases were as proposed performing these anatomical reconstructions fol- follows: (1) no coalescence of the planned tunnels, (2) no lowing a specific recommendation on the direction of the intra-articular invasion at the femorotibial level, and (3) no bone tunnels to avoid all of these potential complications invasion of the femoral trochlea. This allowed us to analyze [19–21]. However, in clinical practice, it is difficult to per- the degree of precision of the technique in different surgical form them in an accurate and replicable manner because a scenarios. specific template guide does not exist to reproduce these angulations. Then, the success of the surgery still depends 3D printing of surgical guides on the experience of the surgeon. In recent years, indications for the use of 3D-printed patient-specific instrumentation Initially, the first cadaveric knee was used as a model to (PSI) technology in orthopaedic surgery procedures have create different PSI guides until the optimal design was significantly increased, and high degrees of precision, accu- obtained for the correct application in the bone. Subse- racy, and reproducibility have been achieved [22, 23]. The quently, eighteen 3D-printed PSI (9 for the medial side and purpose of the study was to analyze whether PSI technology 9 for the lateral side) specifically designed for each cadaveric may be an accurate tool to reproduce the entry point and knee (Fig. 1A–D) were printed internally in our center using direction of femoral bone tunnels for medial and lateral ana- polylactic acid (PLA) and polyvinyl alcohol (PVA) support tomical knee reconstructions based on pre-operative plan- with an Ultimaker 3/S5 printer (Ultimaker, Netherlands) by ning using a knee CT scan. fused deposition modeling (FDM) technology and Ultimaker Cura 4.0 printing software (Ultimaker, Netherlands). During the design and creation of the guide, emphasis was placed on Methods creating small-sized PSI that would fit well to avoid being too aggressive with soft tissue during the surgery. In the This experimental surgery study, based on a human cadav- design process, a tolerance of 0.4 mm was applied. In this eric model, received institutional review board approval way, the guide fits perfectly into the bone edges, considering registered CEIC number 2021/5027. any remaining soft tissue. Surgical planning and guide design Pre-operative computed tomography (CT) scan of each cadaveric knee was performed using a Discovery PET/CT 690 system (GE Healthcare, USA) with the following char- acteristics: a minimum slice thickness of 0.625 mm (1 mm max.), contiguous or overlapping slices (no gaps allowed), a matrix size of 512 × 512, a voxel size of 0.6, and an ana- tomical region default kernel (standard or high resolution) of 90–120 kVp. The images were post-processed to a mesh- volume file, and specific segmentation of the region of inter- est was performed with Materialise Mimics 21.0 (Mimics Innovation Suite, Materialise MV, Belgium). Mesh-volume files were transferred to the design software 3-matic 13.0 (Mimics Innovation Suite, Materialise MV, Belgium) to conduct surgical planning and surgical guide design. For this purpose, the anatomical femoral attachments of the lateral collateral ligament (LCL) and popliteal tendon (PT) on the lateral side [24] and the medial collateral ligament Fig. 1  A Coronal, B lateral, C axial, and D medial view of surgical (MCL) and posterior oblique ligament (POL) on the medial planning including PSI 13 International Orthopaedics (2023) 47:1213–1219 1215 Surgical management Lateral approach A 5-cm lateral incision was performed. Then, the iliotib- ial band (ITB) was opened, and the approach was distally extended between the Gerdy tubercle and the fibular head. Dissection was performed in this location in the proximal and distal directions, exposing the lateral epicondyle until the FCL and PT femoral attachments were visualized. Then, minimal subperiosteal proximal dissection was performed to allow a correct adaptation of PSI to the femoral bone sur- face. To achieve this without damaging the remains of the ligament and capsule attachments, the guides were designed and printed allowing 0.4 mm of tolerance. Then, Kirsch- ner wires were introduced across the whole guide. Finally, Fig. 3  Size of lateral and medial PSI templates both tunnels were drilled with lengths of 25 mm and 8 mm in diameter after removing the PSI following the technique described by Laprade et al. [26]. The PSI design had a low mesh-volume files similar to the pre-operative procedure. profile, so if the position of Kirschner wires was too diver- The accuracy of the use of 3D-printed PSI was assessed by gent, it was possible to break the guide in order to keep the superimposing post-operative CT mesh-volume files onto Kirschner wires in place. pre-operative ones. The entry point deviations of the per- formed tunnels were analyzed from the planned tunnels, Medial approach measured in millimeters (mm). Then, the angular deviation was analyzed and measured in degrees. Angular deviation A longitudinal anteromedial incision of approximately 5 cm is defined as the angle between the vectors crossing from was made over the medial epicondyle. The crural fascia was the centres of the planned and performed tunnels in the x, exposed, and a longitudinal incision was made down the y, and z planes, as shown in Figs. 4A–B and 5A–D. fascia. Once the medial femoral epicondyle was exposed, the attachments of the adductor magnus tendon, MCL, and POL were identified. Subperiosteal dissection was performed. Statistical analysis Once the PSI was adapted to the bone surface, Kirschner wires were inserted. After removing the guide, bone tunnels For all continuous data, the median was used as the cen- were made by a 7-mm drill at a 25 mm in depth, as recom- tral tendency measure, and interquartile ranges (Q1-Q3) mended by some authors [27] (Figs. 2 and 3). were used as the measure of variance. For comparing vari- ables among groups, we used the Kruskal–Wallis test, with Accuracy analysis p-values < 0.05 counting as significant. Post-operative CT scans were performed of each cadav- eric knee, followed by segmentation and the creation of Fig. 2  Medial (A) and lateral (B) approach. Correct PSI tem- plate positioning with Kirschner wires 13 1216 International Orthopaedics (2023) 47:1213–1219 Fig. 4  A–B Superimposition of 3D reconstruction of pre- and post-operative CT scans. Measurements of A entry point deviation and B angular devia- tion between planned (blue) and actual (orange) tunnels Table 1  Cortical entry point deviation between planned and post- surgical tunnels Tunnels Entry point deviation in (mm)a p-Valueb Median Q1-Q3 LCL 1.88 0.91–3.11 0.407 PT 2.93 2.33–3.50 MCL 1.93 1.42–5.68 POL 2.16 1.21–3.60 a Continuous variables are reported as median values and their corre- sponding interquartile range (Q1-Q3). bKruskal-Wallis test. *Differ- ences with a p-value of less than 0.05 were considered statistically significant Table 2  Cortical entry point and angular deviation between planned and postsurgical tunnels Tunnels Angular deviation in (°)a p-Valueb Fig. 5  Superimposition of 3D reconstruction of pre- and post-oper- Median Q1-Q3 ative CT scans. A Coronal, B lateral, C axial, and D medial view. Angular deviation between planned (blue) and actual (orange) tunnels LCL 2.42 1.18–7.67 0.479 PT 4.15 1.79–8.47 MCL 4.50 2.75–9.09 POL 4.69 3.81–6.91 a Continuous variables are reported as median values and their corre- sponding interquartile range (Q1-Q3) Results b Kruskal-Wallis test * Differences with a p-value of less than 0.05 were considered statisti- All surgical guides were properly fitted to the corresponding cally significant anatomical area. Tables 1 and 2 shows the results of cortical entry point deviation and angular deviation between planned and post-surgical tunnels. Notably, all tunnels were located Discussion inside the bone, with no intra-articular invasion. In addition, no tunnel convergences were found. When comparing the vari- The most important finding of this study was the accu- ables among the bone tunnels, no statistically significant differ- racy observed in the direction of the bone tunnels between ences were found, meaning that accuracy levels were similar those planned with the computer software and the ones in all groups analyzed. 13 International Orthopaedics (2023) 47:1213–1219 1217 that were performed in the cadaveric knees using the cus- when performing bone tunnels. Therefore, this technology tom designed 3D-printed PSI. To avoid intra-operative and can be useful in managing these complex injuries. post-operative complications, some authors have studied The second important finding of this study was the the most suitable angulations required for femoral tunnels degree of accuracy found for all bone tunnel entry points, in these complex surgeries, but currently, there is no clear which after surgery was deviated approximately 2 mm as consensus on this topic. To perform lateral reconstruction, compared to 3D surgical planning. This small deviation Moatsche et al. recommended in a descriptive laboratory would have no clinical repercussions. In this sense, when study an anterior angulation of 35° and 0° in the sagittal a conventional technique is used, the surgeon usually has and axial planes, respectively, in the LCL and PT [21]. to intra-operatively decide on the entry points based on However, Gelber et al. described the safest angulations the anatomical attachments of the ligaments, and many applying an anterior angulation of 30° on the axial plane times, this manoeuvre may be difficult due to the absence and 0° on the coronal plane for the LCL and 30° in the or sometimes malposition of the injured ligaments [26, axial and coronal planes for the PT tunnel [19]. When 27]. This technique allows us to devise a pre-operative the injury involves the medial corner, Moatsche et al. plan so that we can be more accurate during the surgical recommended an anterior angulation of 20–40° and 40° procedure. proximally for the MCL in the sagittal and axial planes, Some limitations have been recognized in this study. respectively, and an anterior angulation of 20° and 20° In spite of using a minimally invasive approach, avoid- proximally for the POL in the sagittal and axial planes ing an excessive detachment of soft tissues and using a [21]. Nevertheless, Gelber et al. found that an anterior low profile of PSI, repercussions on soft tissue morbidity and proximal angulation of 30° for the MCL and for the were not evaluated when the surgical approach to adapt POL was the safest direction [20]. Furthermore, all these the designed guide to the femoral bone surface was used. recommendations may be valid only in patients without However, this was not the main purpose of the study, and previous surgery or in the absence of hardware devices in this point may be interesting to evaluate in a clinical trial. the distal femur. Second, no researchers have evaluated the precision of an Regarding the reconstruction of other knee ligaments, expert surgeon making all these bone tunnels at a proper similar studies have determined the optimal angulation for entry point and in the proper direction during these surgi- anterior cruciate ligament (ACL) and anterolateral ligament cal procedures. Then, regarding our study design, further (ALL) tunnel reconstructions in order to avoid coalescence studies are needed to conclude that 3D printing technology between them in inside-out reconstruction techniques [28, is more accurate than conventional surgery performed by 29]. For extra-articular reconstruction of the ALL in con- an expert surgeon. Third, intra-articular bone tunnels were junction with ACL reconstruction, two different tunnels not associated to simulate an anterior or posterior cruciate must be performed, which have similar risk of coalescence ligament reconstruction in our study. This may still be a than the bone tunnels in multiligamentary reconstructions. limitation to strongly recommend using this technology For this purpose, Stodeur et al. recommended an angulation to treat multiligamentary injuries in real patients. Last, of 40° anterior in the axial plane and 10° proximal in the the sample size, which was based on those of other stud- coronal plane for the anterolateral tunnel [28]. ies using the same number of cadaveric pieces [19, 20], Since no specific tool currently exists to drill bone tun- may have been limited, but it was large enough to analyze nels with precision, in this scenario, both the entry point and accuracy. the bone tunnel direction are usually performed freehanded Overall, evaluating these results, one of the potential without any previous planning. Then, the success of this tech- advantages of the use of a specific 3D-printed PSI in the nique still depends on the surgeon’s experience. In addition, treatment of these lesions is that it may be a good tech- the aforementioned studies often make angular recommenda- nique to avoid intra-operative and post-operative com- tions taking into account two planes of space, which is more plications and for managing complex revision cases that feasible in clinical practice but probably less accurate than include previous hardware or bone tunnels. a 3D assessment. No studies have been published using this technology to perform complex knee ligament reconstruc- tions. In recent years, PSI has been successfully applied to different areas in orthopaedics and trauma to improve the Conclusions accuracy of different procedures, such as total knee replace- ment (TKR) [30, 31], upper extremity fractures [32, 33], or The use of 3D-printed PSI for femoral bone tunnel drilling some other procedures showing similar results [34–36]. Dif- in multiple-ligament knee injuries provides accurate and ferences of approximately 5° in the tunnel angle deviation reproducible results and may be a promising tool for use from planning do not have a relevant surgical repercussion in clinical practice. 13 1218 International Orthopaedics (2023) 47:1213–1219 Acknowledgements The authors acknowledge radiology technicians References from Hospital Parc Taulí for the acquisition of CT scans. The authors also acknowledge Joan Carles Oliva for the statistical analysis. 1. Alentron-Geli E, Lazarides AL, Utturkar GM et al (2019) Fac- tors predictive of poorer outcomes in the surgical repair of mul- Author contribution Núria Fernàndez-Poch contributed to the concep- tiligament knee injuries. Knee Surg Sports Traumatol Arthrosc tion and design of the study, experimental surgery, and interpretation 27:445–459. https://​doi.​org/​10.​1007/​s00167-​018-​5053-9 of data and drafted the manuscript. Ferran Fillat-Gomà contributed to 2. Wui J, Ng G, Ali FM (2020) Management of multiligament knee the conception and design of the study, virtual surgical planning and injuries. Efort Open Reviews 5:145–155. https://​doi.​org/​10.​1302/​ surgical guides creation, experimental surgery, and interpretation of 2058-​5241.5.​190012 data. Laia Martinez-Carreres contributed to the conception, design 3. Vicenti G, Solarino G, Carrozzo M et al (2019) Major concern in and coordination of the study, data analysis, and interpretation of data. the multiligament-injured knee treatment : a systematic review. Sergi Coderch-Navarro performed virtual surgical planning and surgi- Injury 50:S89–S94. https://​doi.​org/​10.​1016/j.​injury.​2019.​01.​052 cal guides creation. Christian Yela-Verdú contributed to the conception 4. Peskun CJ, Whelan DB (2011) Outcomes of Operative and non- and design of the study and the experimental surgeries. Sonia Carbó- operative treatment of multiligament knee injuries. Sports Med Cedán contributed to the conception and design of the study. Xavier Arthrosc Rev 19:167–173 Pelfort contributed to the conception and design of the study, virtual 5. Levy BA, Dajani KA, Whelan DB et al (2009) Decision making surgical planning, experimental surgery, and interpretation of data and in the multiligament-injured knee: an evidence-based systematic helped to draft the manuscript. The authors read and approved the final review. J Arthrosc Relat Surg 25:430–438. https://​doi.​org/​10.​ manuscript. 1016/j.​arthro.​2009.​01.​008 6. Arciero RA (2005) Anatomic posterolateral corner knee recon- Funding Open Access Funding provided by Universitat Autonoma de struction. J Arthrosc Relat Surg 21:1–5. https://​doi.​org/​10.​1016/j.​ Barcelona. This work was funded exclusively with funds from Ortho- arthro.​2005.​06.​008 paedics Department of Parc Taulí. 7. Geeslin AG, LaPrade RF (2011) Outcomes of treatment of acute grade-III isolated and combined posterolateral knee injuries. J Data availability Raw data were generated at 3D Surgical Planning Bone Joint Surg 93:1672–1683 Lab at Hospital Parc Taulí. Derived data supporting the findings of 8. Chahla J, Murray IR, Robinson J et al (2019) Posterolateral cor- this study are available from the corresponding author FFG on request. ner of the knee : an expert consensus statement on diagnosis, classification, treatment, and rehabilitation. Knee Surg Sports Code availability Not applicable Traumatol Arthrosc 27:2520–2529. https://​doi.​org/​10.​1007/​ s00167-​018-​5260-4 Declarations 9. Lee DW, Kim JG (2020) Anatomic medial complex reconstruction in serious medial knee instability results in excellent mid-term Ethics approval Approval from Parc Taulí’s Clinical Research and outcomes. Knee Surg Sports Traumatol Arthrosc 28:725–732. Ethics Committee was obtained, with reference number 2021/3019. https://​doi.​org/​10.​1007/​s00167-​019-​05367-9 10. Sanders TL, Johnson NR, Pareek A et al (2018) Satisfactory knee Consent to participate Not applicable. This work is an experimental function after single - stage posterolateral corner reconstruction in study using purchased cadaveric knees. Thus, no informed consent the multi - ligament injured / dislocated knee using the anatomic specific for the study was obtained. single - graft technique. Knee Surg Sports Traumatol Arthrosc 26:1258–1265. https://​doi.​org/​10.​1007/​s00167-​017-​4631-6 Consent for publication Not applicable 11. Bagherifard A, Jabalameli M, Ghaffari S et al (2019) Short to mid-term outcomes of single-stage reconstruction of multiliga- Conflict of interest Fillat-Gomà F. holds stocks of Tailor Surgery SL. ment knee injury. Arch Bone Joint Surg 7:346–353 Fillat-Gomà F. has another affiliation organization not related to this 12. Laprade RF, Chahla J, Dephillipo NN et al (2019) Single-stage particular study but related to orthopedic surgery, Department of Or- multiple-ligament knee reconstructions for sports-related inju- thopedic and Trauma Surgery, Hospital Clinic Barcelona, University ries outcomes in 194 patients. Am J Sports Med 47:2563–2571. of Barcelona. The other authors declare no competing interests. https://​doi.​org/​10.​1177/​03635​46519​864539 13. Camarda L, Arienzo MD, Palermo G et al (2011) Avoiding tunnel Open Access This article is licensed under a Creative Commons Attribu- collisions between fibular collateral ligament and ACL posterolat- tion 4.0 International License, which permits use, sharing, adaptation, dis- eral bundle reconstruction. Knee Surg Sports Traumatol Arthrosc tribution and reproduction in any medium or format, as long as you give 19:598–603. https://​doi.​org/​10.​1007/​s00167-​010-​1299-6 appropriate credit to the original author(s) and the source, provide a link 14. Camarda L, Grassedonio E, Lauria M et al (2016) How to avoid to the Creative Commons licence, and indicate if changes were made. The collision between PCL and MCL femoral tunnels during a simul- images or other third party material in this article are included in the article's taneous reconstruction. Knee Surg Sports Traumatol Arthrosc Creative Commons licence, unless indicated otherwise in a credit line to 24:2767–2772. https://​doi.​org/​10.​1007/​s00167-​014-​3446-y the material. If material is not included in the article's Creative Commons 15. Konan S, Sami F (2010) Femoral fracture following knee liga- licence and your intended use is not permitted by statutory regulation or ment reconstruction surgery due to an unpredictable complica- exceeds the permitted use, you will need to obtain permission directly from tion of bioabsorbable screw fixation : a case report and review of the copyright holder. To view a copy of this licence, visit http://​creat​iveco​ literature. J Orthop Traumatol 11:51–55. https://​doi.​org/​10.​1007/​ mmons.​org/​licen​ses/​by/4.​0/. s10195-​009-​0079-x 16. Axibal DP, Yeatts NC, Hysong AA et al (2021) Intraoperative and early (90-day) postoperative complications and associated vari- ables with multiligamentous knee reconstruction: 15-year Experi- ence from a single academic institution. Arthroscopy: J Arthrosc Relat Surg 1–12. https://​doi.​org/​10.​1016/j.​arthro.​2021.​05.​027 13 International Orthopaedics (2023) 47:1213–1219 1219 17. Hantes ME, Liantsis AK, Basdekis GK et al (2010) Evaluation of reconstruction using an inside-out femoral technique combined the bone bridge between the bone tunnels after anatomic double- with an anterolateral extra-articular reconstruction. Am J Sports bundle anterior cruciate ligament reconstruction: a multidetector Med 50:1205–1214. https://d​ oi.o​ rg/1​ 0.1​ 177/0​ 36354​ 65221​ 07832​ 6 computed tomography study. Am J Sports Med 38:1618–1625. 29. Perelli S, Erquicia JI, Ibañez M et al (2019) Reconstruction with https://​doi.​org/​10.​1177/​03635​46510​363466 modified Lemaire tenodesis: what is the best tunnel angle to 18. Maheshwer B, Drager J, John NS et al (2021) Incidence of intra- decrease risk? Arthroscopy: J Arthrosc Relat Surg 36:1–9. https://​ operative and postoperative complications after posterolateral doi.​org/​10.​1016/j.​arthro.​2019.​08.​042 corner reconstruction or repair: a systematic review of the cur- 30. Tandogan RN, Kort NP, Ercin E et al (2021) Computer-assisted rent literature. Am J Sports Med 49:3443–3452. https://​doi.​org/​ surgery and patient-specific instrumentation improve the accuracy 10.​1177/​03635​46520​981697 of tibial baseplate rotation in total knee arthroplasty compared 19. Gelber PE, Erquicia JI, Sosa G et al (2013) Femoral tunnel drill- to conventional instrumentation: a systematic review and meta- ing angles for the posterolateral corner in multiligamentary knee analysis. Knee Surg Sports Traumatol Arthrosc. https://​doi.​org/​ reconstructions : computed tomography evaluation in a cadaveric 10.​1007/​s00167-​021-​06495-x model. Arthroscopy: J Arthrosc Relat Surg 29:257–265. https://​ 31. Schotanus MGM, Schoenmakers DAL, Sollie R, Kort NP (2017) doi.​org/​10.​1016/j.​arthro.​2012.​08.​015 Patient-specific instruments for total knee arthroplasty can accu- 20. Gelber PE, Masferrer-pino À, Erquicia JI et al (2015) Femoral rately predict the component size as used peroperative. Knee tunnel drilling angles for posteromedial corner reconstructions Surg Sports Traumatol Arthrosc 25:3844–3848. https://​doi.​org/​ of the knee. Arthroscopy: J Arthrosc Relat Surg 31:1764–1771. 10.​1007/​s00167-​016-​4345-1 https://​doi.​org/​10.​1016/j.​arthro.​2015.​03.​007 32. Marcano-Fernández FA, Berenguer A, Fillat-Gomà F et al (2021) 21. Moatshe G, Brady AW, Slette EL et al (2017) Multiple ligament A customized percutaneous three-dimensional-printed guide for reconstruction femoral tunnels: intertunnel relationships and scaphoid fixation versus a freehand technique: a comparative guidelines to avoid convergence. Am J Sports Med 45:563–569. study. J Hand Surg: Eur 46:1081–1087. https://​doi.​org/​10.​1177/​ https://​doi.​org/​10.​1177/​03635​46516​673616 17531​93421​10491​32 22. Wong KC (2016) 3D-printed patient-specific applications in 33. Fillat-Gomà F, Marcano-Fernández FA, Coderch-Navarro S et al orthopedics. Orthop Res Rev 8:57–66 (2021) 3D printing innovation: new insights into upper extremity 23. Jacquet C, Chan-yu-kin J, Sharma A et al (2019) More accu- surgery planning. Injury 52:S117–S124. https://d​ oi.o​ rg/1​ 0.1​ 016/j.​ rate correction using “patient-specific” cutting guides in open- injury.​2021.​01.​048 ing wedge distal femur varization osteotomies. Int Orthop 34. Jones GG, Clarke KLS, Jaere RCM, Cobb SHJP (2018) Do 43:2285–2291 patient-specific instruments ( PSI ) for UKA allow non-expert 24. Chahla J, Moatshe G, Dean CS, Laprade RF (2016) Posterolat- surgeons to achieve the same saw cut accuracy as expert surgeons? eral corner of the knee: current concepts. Arch Bone Joint Surg Arch Orthop Trauma Surg 138:1601–1608. https://​doi.​org/​10.​ 4:97–103 1007/​s00402-​018-​3031-9 25. Laprade RF, Engebretsen AH, Ly TV et al (2007) The anatomy 35. Jud L, Vlachopoulos L, Beeler S et al (2020) Accuracy of three of the medial part of the knee. J Bone Joint Surg 89:2000–2010. dimensional-planned patient-specific instrumentation in femoral https://​doi.​org/​10.​2106/​JBJS.F.​01176 and tibial rotational osteotomy for patellofemoral instability. Int 26. LaPrade RF, Johansen S, Wentorf FA et al (2004) An analysis Orthop 44:1711–1717 of an anatomical posterolateral knee reconstruction: an in vitro, 36. Levy JC, Everding NG, Frankle MA, Keppler LJ (2021) Accuracy biomechanical study and development of a surgical technique. Am of patient-specific guided glenoid baseplate positioning for reverse J Sports Med 32:1405–1414. https://d​ oi.o​ rg/1​ 0.1​ 177/0​ 36354​ 6503​ shoulder arthroplasty. J Shoulder Elbow Surg 23:1563–1567. 262687 https://​doi.​org/​10.​1016/j.​jse.​2014.​01.​051 27. Laprade RF, Wijdicks CA (2012) Surgical technique. development of an anatomic medial knee reconstruction. Clin Orthop Relat Res Publisher's note Springer Nature remains neutral with regard to 470:806–814. https://​doi.​org/​10.​1007/​s11999-​011-​2061-1 jurisdictional claims in published maps and institutional affiliations. 28. Stordeur A, Grange S, Servien E, Blache Y (2022) Optimal com- bination of femoral tunnel orientation in anterior cruciate ligament 13