Tunnel Malposition Research Articles

Use of Fast-Setting Bone Graft Substitute to Allow Single-Stage Revision Anterior Cruciate Ligament Reconstruction

Background: The overall revision rate for primary anterior cruciate ligament reconstruction (ACLR) has increased over the past decade, with the commonest mode of failure being a combination of traumatic, technical, and biological factors. The challenge in revision ACLR is the need to address malpositioned or widened tunnels with the ideal scenario being single-stage revision, with widened and type 2 tunnels being the most difficult scenarios to deal with. Tunnels can be filled using autograft, allograft, and more recently described bone graft substitute (BGS). In this video, we describe a technique using fast-setting BGS to fill the problem of malpositioned tunnel or tunnels to allow single-stage revision ACLR. Indications: This technique is indicated in patients undergoing revision ACLR where tunnels are nearly right (type 2) with no widening at the joint surface aperture. Technique Description: Following preparation of the notch, the femoral tunnels are prepared in the normal fashion to remove all the previous graft and to create fresh bleeding surfaces. The fluid in the knee is completely drained, and the femoral tunnel is repeatedly dried with ribbon gauze that is left in place until ready to inject. The BGS, genex (Biocomposites Ltd), is mixed and loaded into the delivery syringe before injecting arthroscopically. After 15 minutes, the new anatomic femoral tunnel is then prepared in routine fashion. The same steps are repeated for the tibial tunnel. Results: Twenty patients underwent single-stage revision ACLR using this technique. There have been no reruptures in this series. All eligible patients at the 12-month follow-up had grade 0 or 1 laxity on clinical examination and full incorporation of the BGS on radiographs. There were no complications related to the BGS during the intra- or postoperative period. Discussion/Conclusion: We describe a technique that allows revision ACLR to be performed as single stage in a subset of patients with type 2 tunnels with successful short- to mid-term results. We have found this to be a safe and effective way to avoid 2-stage surgery in a subgroup of cases who have a challenging problem for surgeons to manage. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Fascia Lata Allograft Medial Patellofemoral Ligament Reconstruction—Restore the Nature as Close as Possible

Various surgical techniques for medial patellofemoral ligament (MPFL) reconstruction have been described, commonly using hamstring auto- or allografts. Despite their widespread use, these techniques have limitations due to the tubular structure of the hamstring tendons, which does not match the flat, sail-like anatomy of the MPFL. Furthermore, over- or undertensioning of the graft due to tunnel misplacement remains a significant risk, even if anatomic and radiologic landmarks are used. To address these issues, a fascia lata allograft MPFL reconstruction with assessment of angular anisometry is presented. This technique allows for reconstruction of the MPFL as close as possible to its nature with a flat and wide patellar attachment and a gradual transition of maximal tension across the graft fibers, depending on the knee flexion angle. Precise intraoperative control of predefined graft angular anisometry allows for achievement of the desired amount of tension at specific flexion angles. This mitigates the risk of under- or overtensioning and subsequently ensures proper medial-lateral mobility of the patella.

A tight anterosuperior intercondylar notch may increase the risk of cyclops syndrome after anterior cruciate ligament reconstruction using a quadruple semi-tendinosus short autograft

BackgroundCyclops syndrome is loss of terminal knee extension caused by a fibrous nodule developed in the anterior intercondylar notch. The many known risk factors include preoperative motion-range limitation, tibial tunnel malposition, and tight hamstrings. The primary objective of this study was to assess whether intercondylar notch size was associated with the risk of cyclops syndrome or graft tear after anterior cruciate ligament (ACL) reconstruction using a quadruple semi-tendinosis autograft. The secondary objective was to determine whether intercondylar notch size was associated with functional outcomes. HypothesisA narrow intercondylar notch is associated with higher risks of cyclops syndrome and poor functional outcomes. MethodsConsecutive patients who underwent ACL reconstruction by quadruple semi-tendinosus autograft were included retrospectively. Preoperative magnetic resonance imaging scans were assessed by a single senior surgeon, who determined the conventional notch width index (NWI) and the anterior NWI (aNWI) for each patient. ResultsThe 120 included patients had a mean follow-up of 2.4±0.8 years. Among them, 20 (16.7%) experienced cyclops syndrome and 7 (5.8%) graft rupture. At last follow-up, 26 (21.7%) had not returned to sports and only 47 (39.2%) had returned to sports at the pre-injury level. The mean Lysholm score was 87.9±13.5 and the main subjective IKDC score was 84±13. A narrow notch was significantly associated with lower likelihoods of returning to sports (p=0.001), returning to the same sport (p<0.0001), and returning to the pre-injury sport level (p=0.004). By multivariate analysis, only the aNWI index was significantly associated with the risk of cyclops syndrome (p<0.0001). An aNWI index lower than 0.18 had 85% sensitivity and 78% specificity for predicting cyclops syndrome. ConclusionA narrow anterosuperior intercondylar notch may increase the risk of cyclops syndrome after ACL reconstruction using a quadruple semi-tendinosus graft but is not associated with the risk of graft rupture. Level of evidenceIV, retrospective observational cohort study.

Patient specific instrumentation in ACL reconstruction: a proof-of-concept cadaver experiment assessing drilling accuracy when using 3D printed guides

IntroductionAccurate positioning of the femoral tunnel in ACL reconstruction is of the utmost importance to reduce the risk of graft failure. Limited visibility during arthroscopy and a wide anatomical variance attribute to femoral tunnel malposition using conventional surgical techniques. The purpose of this study was to determine whether a patient specific 3D printed surgical guide allows for in vitro femoral tunnel positioning within 2 mm of the planned tunnel position.Materials and MethodsA patient specific guide for femoral tunnel positioning in ACL reconstruction was created for four human cadaveric knee specimens based on routine clinical MRI data. Fitting properties were judged by two orthopedic surgeons. MRI scanning was performed both pre- and post-procedure. The planned tunnel endpoint was compared to the actual drilled femoral tunnel.ResultsThis patient specific 3D printed guide showed a mean deviation of 5.0 mm from the center of the planned femoral ACL origin.ConclusionIn search to improve accuracy and consistency of femoral tunnel positioning in ACL reconstruction, the use of a patient specific 3D printed surgical guide is a viable option to explore further. The results are comparable to those of conventional techniques; however, further design improvements are necessary to improve accuracy and enhance reproducibility.

Reimagined MPFL Reconstruction: Retinacular Fixation of the Doubled Hamstring Graft at the Patella and Suture Anchor-Based Femoral Fixation.

Lateral patellar dislocation is frequently observed among teenagers and young adults. There is no consensus on the best type of graft or fixation strategy for the femur and patella, and complications such as iatrogenic patella fracture, tunnel malposition, and grafting failure are common. The objective of our research is to find out the functional outcome of a new method of medial patellofemoral ligament (MPFL) reconstruction, which involves two key components: (1) patellar fixation is accomplished by suturing the two limbs of the looped doubled hamstring graft in a divergent fashion to the retinaculum at the medial border of the upper half of patella and (2) the placement of a suture anchor tied to the graft at the isometric point on the medial femur condyle. This study is a retrospective assessment of patients who underwent MPFL reconstruction at our hospital between September 2018 and August 2020. Patients were monitored for at least 2 years after the initial procedure until August 2022. A total of 29 patients were recruited for the study, with 22 being females and the average age being 30.38 years. During the postoperative period, none of the participants experienced instability, redislocation, patellar/femoral fractures, or abnormal distal femur growth. The Tegner-Lysholm knee score was good to excellent for 17 (58.6%) participants, fair for 10 (34.5%) participants, and poor for 2 (6.9%) participants. The Kujala anterior knee pain score was more than 80 for 19 (65.5%) participants. This research presents a significant achievement rate of the surgical procedure, accompanied by the mean Tegner-Lysholm knee score of 82.68 and the mean Kujala anterior knee pain score of 82.71. Notably, there were no complications observed in the postoperative period.

Two-Stage Revision ACL Reconstruction with Arthroscopic Tunnel Bone Grafting

Background: Anterior cruciate ligament (ACL) reconstruction is a common orthopedic surgery, and due to the increased number of primary reconstructions being performed, the number of revision ACL reconstructions is also increasing. Indications: Two-stage revision ACL reconstruction has lower failure rates compared to 1-stage and is indicated when significant tunnel expansion has occurred or malpositioned tunnels prohibit an adequate reconstruction. In this presentation, 2-stage revision ACL reconstruction was performed with an arthroscopic bone grafting technique of both the femoral and tibial tunnels secondary to tunnel osteolysis. Technique Description: Standard diagnostic arthroscopy is performed, and any chondral or meniscal pathology is addressed. The remnant ACL graft and all hardware are removed. The tunnels are debrided thoroughly. Using a modified syringe, the tunnels are packed with a mixture of cancellous bone chips and cortical fibers that have been hydrated with whole blood and platelet-rich plasma (PRP). The patient is placed into a brace postoperatively, and a computed tomography (CT) is obtained approximately 4 to 6 months postoperatively to assess for bone healing. Revision ACL reconstruction is performed once indicated with standard rehabilitation and return to play protocol. Results: Both 1-stage and 2-stage revision ACL reconstructions have been demonstrated to have significant improvement in outcomes scores preoperatively to postoperatively. However, 2-stage has lower failure rates compared to single-stage and has a high return to level of play. Discussion/Conclusion: Revision ACL reconstruction is becoming more commonly performed, and 2-stage revision is frequently required due to multiple factors. In this video, we demonstrate bone grafting for revision ACL reconstruction for tunnel osteolysis. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

The importance of a structured failure analysis in revision acromioclavicular joint surgery: A multi-rater agreement on the causes of stabilization failure from the ISAKOS shoulder committee

BackgroundAcromioclavicular joint (ACJ) stabilizations are associated with a high overall failure rate with 9.5% of these patients requiring subsequent revision surgery. Consequently, understanding the specific cause of primary ACJ stabilization failure is paramount to improving surgical decision-making in this challenging patient cohort. PurposeTo (1) identify risk factors and mechanisms for failure following primary arthroscopically-assisted ACJ stabilization to highlight the importance of conducting a detailed failure analysis and to (2) establish revision strategies based on real-life cases of primary failed ACJ stabilization. Study designLevel of evidence IV. MethodsA survey was shared internationally among members of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) shoulder committee. The survey contained failure analysis of 11 real-life cases of failed primary arthroscopically-assisted ACJ stabilization. For each case, a thorough patient history, standardized radiographs, and CT scans were provided. Participants were asked to give their opinion on bone tunnel placement, cause of failure (biological, technical, traumatic, or combined), the stabilization technique used, as well as give a recommendation for revision. ResultsSeventeen members of the ISAKOS shoulder committee completed the survey. Biological failure was considered the most common cause of failure (47.1%), followed by technical (35.3%) and traumatic (17.6%) failure. The majority deemed two modifiable factors (i.e., patient's profession and sport) as well as non-modifiable factors (i.e., patient's age and time from trauma to initial surgery) to be risk factors for failure. In 10 of 11 cases, the correct fixation device was used in the primary setting (90.9%; 52.8–82.4% agreement); however, in eight of those cases, the technique was not performed correctly (80.0%; 58.8–100% agreement). In 8 of all 11 cases, the majority recommended an arthroscopically assisted technique with graft augmentation for revision (52.9–58.8% agreement). ConclusionBiological failure and technical failure are the most common reason for failure in primary ACJ stabilization followed by traumatic failure. Besides, biological failure can be triggered by technical errors such as clavicular or coracoidal tunnel misplacement. Consequently, a detailed failure analysis including preoperative CT should be conducted on the causes of primary ACJ failure, and, if possible, an arthroscopically-assisted technique with graft augmentation should be prioritized in revision ACJ surgery. Clinical relevanceACJ stabilizations are associated with a high overall failure rate - potentially due to biological and technical properties. When encountering failed arthroscopically-assisted ACJ stabilization, a detailed failure analysis should be conducted on the causes of primary ACJ failure. Furthermore, an arthroscopically-assisted revision stabilization is feasible in most cases.

Femoral Tunnel Malposition, Increased Lateral Tibial Slope, and Decreased Notch Width Index Are Risk Factors for Non-Traumatic Anterior Cruciate Ligament Reconstruction Failure

To identify risk factors for patients who sustain nontraumatic anterior cruciate ligament reconstruction (ACLR) failure. A retrospective analysis was performed on patients undergoing primary or revision ACLR in our institution between 2010 and 2018. Patients sustaining insidious-onset knee instability without history of trauma were identified as nontraumatic ACLR failure and assigned to the study group. The control group of subjects who showed no evidence of ACLR failure with minimum 48-month follow-up were matched in a 1:1 ratio based on age, sex, and body mass index. Anatomic parameters including tibial slope (lateral [LTS], medial [MTS]); tibial plateau subluxation (lateral [LTPsublx], medial [MTPsublx]); notch width index (NWI); and lateral femoral condyle ratio were measured with magnetic resonance imaging or radiography. Graft tunnel position was assessed using 3-dimensional computed tomography and reported in 4 dimensions: deep-shallow ratio (DS ratio) and high-low ratio for femoral tunnel, anterior-posterior ratio and medial-lateral ratio for tibial tunnel. Interobserver and intraobserver reliability were evaluated by the intraclass correlation coefficient (ICC). Patients' demographic data, surgical factors, anatomic parameters, and tunnel placements were compared between the groups. Multivariate logistic regression and receiver operating characteristic curve analysis was used to discriminate and assess the identified risk factors. A total of 52 patients who sustained nontraumatic ACLR failure were included and matched with 52 control subjects. Compared to patients with intact ACLR, those who sustained nontraumatic ACLR failure showed significantly increased LTS, LTPsublx, MTS, and deceased NWI (all P < .001). Moreover, the average tunnel position in the study group was significantly more anterior (P < .001) and superior (P= .014) at the femoral side and more lateral (P= .002) at the tibial side. Multivariate regression analysis identified LTS (odds ratio [OR]= 1.313; P= .028), DS ratio (OR= 1.091; P= .002), and NWI (OR= 0.813; P= .040) as independent predictors of nontraumatic ACLR failure. LTS appeared to be the best independent predictive factor (area under the curve [AUC]= 0.804; 95% confidence interval [CI], 0.721-0.887), followed by DS ratio (AUC= 0.803; 95% CI, 0.717-0.890), and NWI (AUC= 0.756; 95% CI, 0.664-0.847). The optimal cutoff values were 6.7° for increased LTS (sensitivity= 0.615, specificity= 0.923); 37.4% for increased DS ratio (sensitivity= 0.673, specificity= 0.885); and 26.4% for decreased NWI (sensitivity= 0.827, specificity= 0.596). Intraobserver and interobserver reliability was good to excellent, with ICCs ranging from 0.754 to 0.938 for all radiographical measurements. Increased LTS, decreased NWI, and femoral tunnel malposition are predictive risk factors for nontraumatic ACLR failure. Level III, retrospective comparative study.

Poster 129: Biomechanical Evaluation of the Isometry of Medial Patellofemoral Ligament Reconstruction Grafts Fixed at Non-Anatomic Femoral Insertion Points

Objectives: In MPFL reconstruction surgery, achieving perfect placement of the femoral tunnel intraoperatively is difficult. An understanding of the effects femoral tunnel malpositioning has on graft isometry is crucial to minimizing instability or overconstraint which leads to anterior knee pain, increased patellofemoral contact pressures, or graft failure. The purpose of this study was to identify differences in MPFL reconstruction graft isometry with femoral tunnel malpositioning, specifically evaluating isometry differences as the femoral position is moved anterior, posterior, proximal, and distal relative to the femoral radiographic landmark of the MPFL, Schottle’s point. Methods: A biomechanical study evaluating 11 fresh frozen cadaveric knees was conducted. Non-elastic suture, used as an MPFL graft analogue, was anchored at Schottle’s point with the knee at 30° of flexion, and at 5 mm and 10 mm anterior, posterior, superior, and distal to Schottle’s point. A draw wire displacement sensor was used to evaluate length changes of the MPFL graft analogue through 0-120° of knee flexion. Knee flexion position was continuously measured using a motion tracking system. Pairwise t-tests with Bonferroni corrections were used to compare isometry between Schottle’s point and non- anatomic femoral insertion points. Results: Grafts placed at Schottle’s point demonstrated mild anisometry with tightening in extension and loosening in flexion. Similarly, grafts placed distally and posteriorly also demonstrated tightening in extension and loosening in flexion. Grafts placed anteriorly and proximally demonstrated tightening in flexion. Mean and range of total draw wire excursion over full ROM across specimens is shown in Figure 1. The mean draw wire length was found to be greater with further displacement from Schottle’s point in all directions but posterior. Pairwise comparisons relative to Schottle’s point found grafts placed in the proximal or distal direction demonstrated significant differences in MPFL excursion, while grafts placed in the anterior or posterior direction did not (10 mm proximal: 0.36 (p=0.028), 5 mm distal: 0.14 (p=0.012), 10 mm distal: 0.22 (p&lt;0.001)) (Table 1). Conclusions: In order to minimize the risk of graft tightening during knee flexion, if deviating from Schottle’s point, it is safest to err posterior or distal in femoral tunnel position. Travel away from Schottle’s point in the proximal or distal direction has the greatest effects on graft isometry. The greatest risk of overconstraint and graft tightening in flexion is seen with proximal placement of the femoral insertion point.

#4047 ULTRASOUND-GUIDED RIGHT INTERNAL JUGULAR TUNNELED CATHETER INSERTION FOR HAEMODIALYSIS: PRACTICES AND OUTCOMES FROM A SINGLE CENTRE

Abstract Background and Aims Internal jugular vein tunneled catheters are important vascular access for haemodialysis (HD). In our practice, Left-sided internal jugular (LIJ) catheter insertion is performed in radiology under direct X-ray screening. Most right-side internal jugular (RIJ) catheters are inserted under ultrasound guidance in dedicated renal procedure rooms. Vascular access can become challenging with the potential for venous stenosis and thrombosis with catheter use. The aims of this study are to evaluate our practices and outcomes of non-radiologically inserted RIJ tunneled HD catheters and to investigate the predictors of procedure failure. Method 200 successive RIJ tunnel HD catheters inserted from June 2016 under ultrasound guidance at our centre were included in this analysis. Data including demographics, co-morbidities, first or higher order insertion, outcome (success or failed attempt), and immediate complications were collated from electronic patient records. Binary logistic regression analysis was conducted to investigate the predictor for failure in catheter insertion. Results Of the 200 patients, 152 (76%) were first-time insertions and 48 (24%) were second or higher-order insertions. The median age of our cohort was 58 years, with a predominance of males (68%) and white ethnicity (82%). 36.5% were diabetic, with 37.5% having a history of cardiovascular disease. Nearly 30% of patients were on an antiplatelet agent, and 8% were on anticoagulants, which were appropriately managed before line insertion. Pre-operative median haemoglobin was 93 g/dl, with clotting screen and platelet counts in the target range. There was a statistically significant difference in the success of insertion, depending on the insertion being first or subsequent (96.1% vs 81.2%; p = 0.001). The reason for failure in insertion included on-table observation of a small calibre vein on ultrasound or failure to thread wire/dilator due to possible stenosis or thromboses. All line rewire (12/48) procedures were performed successfully. Immediate complication (&amp;lt;1 week) was recorded in 9% of patients, predominantly tunnel bleeding (n = 7) and malposition (deep or high; n = 7) (Table 1). Second or higher-order RIJ catheter insertion showed a higher risk for failure in a multivariable binary logistic regression analysis. (OR: 6.4; CI: 2.1-20.5; P = 0.002) (Figure 1). Of the higher-order insertions, the longer duration between the first and subsequent catheters showed a higher risk for failure (OR:1.19; CI-1.04-1.4; p = 0.010). Conclusion Second or higher-order catheter insertions with a longer duration between the first and the subsequent insertion carry a significant risk of failure due to vein stenosis and thrombosis. Therefore, a careful case-to-case triaging of patients based on previous access history is warranted before listing patients for routine ultrasound-guided insertion.

3D assessment of graft malposition after ACL reconstruction: Comparison of native and 11o'clock ligament orientations

BackgroundFemoral tunnel malposition makes up the majority of technical failures for ACL reconstructive surgery. The goal of this study was to develop adolescent knee models that accurately predict anterior tibial translation when undergoing a Lachman and pivot shift test with the ACL in the 11o’clock femoral malposition (Level of Evidence: IV). MethodsFEBio was used to build 22 subject-specific tibiofemoral joint finite element representations. To simulate the two clinical tests, the models were subject to loading and boundary conditions established in the literature. Clinical, historical control data were used to validate the predicted anterior tibial translations. ResultsA 95% confidence interval showed that with the ACL in the 11o’clock malposition, the simulated Lachman and pivot shift tests produced anterior tibial translations that were not statistically different from the in vivo data. The 11o’clock finite element knee models resulted in greater anterior displacement than those with the native (approximately 10o’clock) ACL position. The difference in anterior tibial translation between the native and 11o’clock ACL orientations was statistically significant. ConclusionClinically, by understanding the impact that ACL orientation has in anterior tibial displacement biomechanics, surgical interventions can be improved to prevent technical errors from occurring. The integration of this methodology into surgical practice not only allows for anatomical visualization prior to surgery, but also creates the opportunity to optimize graft placement, thus improving post-surgical outcomes.

Association of Tibial Tubercle–Trochlear Groove Distance With Risk of ACL Graft Failure

Background: Limited evidence suggests a positive correlation between tibial tubercle–trochlear groove (TT-TG) distance and the risk of native anterior cruciate ligament (ACL) tear. The relationship between TT-TG distance and the risk of ACL graft failure is unknown. Hypothesis: TT-TG distance is independently associated with risk of ACL graft failure. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent ACL revision surgery between 2010 and 2018 at a single institution were identified. A control cohort underwent primary ACL reconstruction (ACLR) between 2006 and 2015, with no evidence of graft failure at 8.1 ± 2.5 years postoperatively. Record review included anthropometrics, graft type, and estimated Tegner activity score at ≥6 months after primary ACLR. Magnetic resonance imaging (MRI) scans after native ACL tear (controls) or graft failure (revision cohort) were assessed for (1) TT-TG distance, (2) proximal tibial slopes, (3) depth of tibial plateau concavity, and (4) tunnel position (revision cohort). Associations between ACL graft failure and MRI measurements, surgical variables, and patient characteristics were evaluated with logistic regression analyses. Sensitivity analyses, excluding patients with tunnel malposition, were performed to confirm multivariable results in patients with “ideal” tunnel placement. Results: Participants included 153 patients who underwent revisions and 144 controls. Controls were older than the patients who underwent revision (26.6 ± 8.8 vs 20.6 ± 7.3 years; P &lt; .001). The mean TT-TG distance and lateral posterior tibial slope (PTS) were smaller for the control group than for the revision group (TT-TG: 9.3 ± 3.9 vs 11.2 ± 4.2 mm; P &lt; .001; lateral PTS: 6.2° ± 3.3° vs 7.2° ± 3.6°; P = .01). TT-TG distance, lateral PTS, and age were associated with risk of ACL graft failure by multivariable analysis (OR, 1.15; 95% CI, 1.07-1.23; P &lt; .001; OR, 1.13; 95% CI, 1.04-1.22; P = .004; and OR, 0.90; 95% CI, 0.87-0.94; P &lt; .001, respectively). With sensitivity analyses, TT-TG distance, lateral PTS, and age at index surgery remained significantly and independently associated with ACL graft failure. Conclusion: Increased TT-TG distance, increased lateral PTS, and younger age are independently associated with increased odds of ACL graft failure. Patients with these characteristics may require a more comprehensive strategy to reduce the risk of ACL reinjury.

Failure modes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

The reason for graft failure after anterior cruciate ligament reconstruction (ACLR) is multifactorial. Controversies remain regarding the predominant factor and incidence of failure aetiology in the literature. This review aimed to provide a meta-analysis of the literature to evaluate the relative proportion of various failure modes among patients with ACLR failure. The PubMed, Embase, Cochrane Library, Web of Science, and EBSCO databases were searched for literature on ACLR failure or revision from 1975 to 2021. Data related to causes for ACLR surgical failure were extracted, and a random effects model was used to pool the results, which incorporates potential heterogeneity. Failure modes were compared between different populations, research methods, graft types, femoral portal techniques, and fixation methods by subgroup analysis or linear regression. Funnel plots were used to identify publication bias and small-study effects. A total of 39 studies were analyzed, including 33 cohort studies and six registry-based studies reporting 6578 failures. The results showed that among patients with ACLR failure or revision, traumatic reinjury was the most common failure mode with a rate of 40% (95% CI: 35-44%), followed by technical error (34%, 95% CI: 28-42%) and biological failure (11%, 95% CI: 7-15%). Femoral tunnel malposition was the most common cause of the technical error (29%, 95% CI: 18-41%), with more than two times higher occurrence than tibial tunnel malposition (11%, 95% CI: 6-16%). Traumatic reinjury was the most common factor for ACLR failure in European populations and in recent studies, while technical errors were more common in Asian populations, earlier studies, and surgery performed using the transtibial (TT) portal technique. Biological factors were more likely to result in ACLR failure in hamstring (HT) autografts compared to bone-patellar tendon-bone (BPTB) autografts. Trauma is the most important factor leading to surgical failure or revision following ACLR. Technical error is also an important contributing factor, with femoral tunnel malposition being the leading cause of error resulting in failure.

Patient-Individualized Identification of Medial Patellofemoral Ligament Attachment Site to Femur Using "CLASS" MRI Sequences.

Malposition of the femoral tunnel during medial patellofemoral ligament (MPFL) reconstruction may increase the risk of recurrence of patellar dislocation due to isometric changes during flexion and extension. Different methods have been described to identify the MPFL isometric point using fluoroscopy. However, femoral tunnel malposition was found to be the cause of 38.1% of revisions due to patellar redislocation. This high rate of malposition has raised the question of individual anatomical variability. Magnetic resonance imaging (MRI) was performed on 80 native knees using the CLASS (MRI-generated Compressed Lateral and anteroposterior Anatomical Systematic Sequence) algorithm to identify the femoral MPFL insertion. The insertions were identified on the MRI views by 2 senior orthopaedic surgeons in order to assess the reliability and reproducibility of the method. The distribution of the MPFL insertion locations was then described in a 2-plane coordinate system and compared with MPFL insertion locations identified with other methods in previously published studies. The CLASS MPFL footprint was located 0.83 mm anterior to the posterior cortex (line 1) and 3.66 mm proximal to the Blumensaat line (line 2). Analysis demonstrated 0.90 and 0.89 reproducibility and 0.89 and 0.80 reliability of the CLASS method to identify the anatomical femoral MPFL insertion point. The distribution did not correlate with previously published data obtained with other methods. The definitions of the MPFL insertion point in the studies by Schöttle et al. and Fujino et al. most closely approximated the CLASS location in relation to the posterior femoral cortex, but there were significant differences between the CLASS method and all 4 previously published methods in relation to the proximal-distal location. When we averaged the distances from line 1 and line 2, the method that came closest to the CLASS method was that of Stephen et al., followed by the method of Schöttle et al. The CLASS algorithm is a reliable and reproducible method to identify the MPFL femoral insertion from MRI views. Measurement using the CLASS algorithm shows substantial individual anatomical variation that may not be adequately captured with existing measurement methods. While further research must target translation of this method to clinical use, we believe that this method has the potential to create a safe template for sagittal fluoroscopic identification of the femoral tunnel during MPFL surgical reconstruction. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

After MPFL reconstruction, femoral tunnel widening and migration increase with poor tunnel positioning and are related to poor clinical outcomes.

Isolated MPFL reconstruction (iMPFLR) is increasingly used for the surgical treatment of treatment for recurrent patella dislocation. The purpose of this study was to evaluate the influence of tunnel widening and migration on clinical outcomes after iMPFL using a CT-scannographic analysis at 6months postoperatively. One hundred and sixty patients (91 females for 69 males) with an average age of 23years [14-54] who underwent iMPFLR and had an evaluation scan at 6months postoperatively were evaluated with a mean follow-up of 97 ± 89months [12 to 166]. Functional International Knee Documentation Committee (IKDC) Score, Kujala score, and joint mobility were assessed preoperatively, at 6months and at the latest follow-up. The IKDC and Kujala scores were expressed as the difference between pre- and postoperative scores (dIKDC and dKujala). The position of the femoral tunnel was assessed according to the Schöttle criteria on post-operative radiographic profiles. Tunnel widening (at three levels of measurement) and the migration of the center of the tunnel were studied on a CT-scan analysis at 6months. Any correlation and regression between the evolution of the clinical scores and the measured scannographic parameters were investigated. The relationships between tunnel position and tunnel changes were also studied. Between pre- and post-op, the IKDC (45 ± 13 to 80 ± 15, p < 0.001) and Kujala (55 ± 11 to 87 ± 12, p < 0.001) scores were significantly improved. Patients with tunnel changes had decreased clinical and functional results at 6months post-op of an iMPFLR (p < 0.001). These changes in the femoral tunnel, evidenced by a tunnel entrance widening and migration of the tunnel center, were related to an initial malposition of the tunnel (p < 0.001). In iMPFLR, changes in the femoral tunnel, corresponding to dilatation and migration of the tunnel center, may occur. These changes are increased by the initial malpositioning of the femoral tunnel and are correlated with less good clinical and functional outcomes. Level IV.

Predictors of Graft Failure After Primary Medial Patellofemoral Ligament Reconstruction.

The tibiofemoral rotation angle has been found to be higher in patients with recurrent patellar dislocations (RPDs) than in healthy people; however, little is known about the clinical significance of this finding. To determine whether an increased tibiofemoral rotation angle is associated with graft failure after primary medial patellofemoral ligament reconstruction (MPFL-R) and to investigate the role of the tibiofemoral rotation angle in predicting MPFL-R failure in patients with RPDs. Case-control study; Level of evidence, 3. We retrospectively analyzed the records of 632 consecutive patients with clinically diagnosed RPDs from 2011 to 2018. Postoperative stress radiography of the patellofemoral joint was performed to identify whether the graft failed. After a review, 33 patients who showed MPFL-R failure were allocated to the failure group. They were matched 1:2 to 66 participants who underwent successful MPFL-R (control group). The cutoff value and area under the curve (AUC) of the tibiofemoral rotation angle for predicting graft failure after primary MPFL-R were determined, and the risk factors for MPFL-R failure were assessed by multivariate logistic regression analysis. The tibiofemoral rotation angle was significantly higher in the failure group than in the control group (16.4° ± 5.6° vs 6.4° ± 4.5°, respectively; P < .001). The cutoff value of the tibiofemoral rotation angle for predicting graft failure was 12.3° (sensitivity, 81.8%; specificity, 89.4%; AUC, 0.920). Overall, 3 risk factors for MPFL-R failure were determined: excessive tibiofemoral rotation (≥12.3°) (odds ratio [OR], 13.159 [95% CI, 2.469-70.139]; P = .003), a preoperative high-grade J-sign (OR, 7.674 [95% CI, 1.232-47.809]; P = .029), and a femoral tunnel malposition (OR, 6.976 [95% CI, 1.077-45.187]; P = .042). In this study, excessive tibiofemoral rotation, a preoperative high-grade J-sign, and a femoral tunnel malposition were identified as risk factors for graft failure after primary MPFL-R in patients with RPDs. More importantly, excessive tibiofemoral rotation ( ≥ 12.3°) may predict the failure of primary MPFL-R, which can help surgeons easily identify high-risk patients of MPFL-R failure before surgery.

Arthroscopic Bone Graft Technique for Two-Stage Revision Anterior Cruciate Ligament Reconstruction

Revision anterior cruciate ligament reconstruction is an increasingly common procedure, with 2-stage surgery often required to address large bone defects and malpositioned tunnels. The arthroscopic bone grafting technique described herein uses morselized allograft bone to provide reproducible fill of asymmetrical bone defects without autograft harvest or additional loss of native bone. The second stage of the anterior cruciate ligament reconstruction can typically proceed 6 months following bone grafting.

Over-The-Top Technique for Revision ACL Reconstruction with Achilles Allograft and Associated Lateral Extra-articular Tenodesis

Revision anterior cruciate ligament reconstruction (ACL-R) is made challenging by the frequent presence of rotatory instability, tunnel malpositioning and widening, and limited autograft options. Lateral extra-articular tenodesis (LET), alternative tunnel routing, and the use of allograft tissue can be used to manage these challenges. This Technical Note describes revision ACL-R using the over-the-top (OTT) technique with Achilles tendon allograft with concomitant LET. The surgical approach involves routing the graft around the posterior aspect of the lateral femoral condyle, and then deep to the iliotibial band to a site just medial to Gerdy’s tubercle, with staple fixation on the lateral femur for the ACL-R and anterolateral tibia for the LET. The OTT technique with LET provides a versatile approach for the management of failed ACL-R by circumventing challenges in revision ACL-R and addressing rotatory instability, a contributing factor to prior graft failure.

Revision Anterior Cruciate Ligament Reconstruction Using Bone Dowels

Background: Revision anterior cruciate ligament (ACL) reconstruction is technically challenging and may require the use of bone dowels in either 1 or 2 stages. Indications: The indications for bone dowels include tibial or femoral tunnel malposition or widening of the tunnels. In the patient case, the tibial tunnel aperture was positioned far medial to the native ACL insertion with a horizontal tunnel trajectory and the femoral tunnel was vertical. In addition, there was tunnel widening to 12 mm of both tibial and femoral tunnels. Technique Description: A bone-patellar tendon-bone autograft was harvested and diagnostic arthroscopy was performed. The previous tibial tunnel was sequentially reamed from 8 to 12 mm to adequately overdrill the previous widened tunnel. Next, the femoral tunnel was reamed to 12 mm in similar fashion. Using a tamp and guide pin, a 12 × 30-mm allograft bone dowel was then malleted into the femoral tunnel until it was flush with the medial aspect of the lateral femoral condyle. Another 12 × 30-mm bone dowel was then advanced into the tibial tunnel until it was just below the native articular margin. With the bone dowels securely in place, the ACL reconstruction using the harvested bone-patellar tendon-bone autograft was performed. Results: Werner et al reported a study of 12 patients who had excellent incorporation of femoral tunnel allograft bone dowels and comparable objective and subjective scoring to 2-stage techniques. Dragoo et al reported a study of 18 patients with tibial tunnel allograft bone dowels that demonstrated significant increases in patient-reported outcome measures and a significant decrease in tunnel widening. Discussion/Conclusion: Revision ACL reconstruction may require bone dowels if there are malpositioned tunnels or if there is tunnel widening. Overall, the literature demonstrates that 1-stage revision outcomes have been comparable to reported 2-stage revision outcomes, both of which are satisfactory.

Comparison of Arthroscopic versus Open Placement of the Fibular Tunnel in Posterolateral Corner Reconstruction.

Precise fibular tunnel placement in posterolateral corner (PLC) reconstruction is crucial in restoring rotational and lateral stability. Despite the recent progress of arthroscopic PLC reconstruction techniques, landmarks for arthroscopic fibular tunnel placement and a comparison to open tunnel placement have not yet been described. This study aimed to (1) identify reasonable soft-tissue and bony landmarks, which can be identified by either arthroscopy, fluoroscopy, or open surgery in anatomic fibular tunnel placement and (2) to compare accuracy and reliability of arthroscopic fibular tunnel placement with open surgery. In a retrospective study, 41 magnetic resonance images (MRIs) of the knee were analyzed with emphasis on distances of an ideal anatomic fibular tunnel to 11 soft-tissue and bony landmarks. Subsequently, in eight cadaver knees, the ideal fibular tunnel was created arthroscopically and with a standard open technique from antero-latero-inferior to postero-medio-superior with a 2-mm K-wire. Positions of both tunnels were compared on postinterventional computed tomography scans. Based on MRI measurements, the anatomic tunnel entry should be 14.50 (±2.18) mm distal to the tip of the fibular styloid and 10.76 (±1.37) mm posterior to the anterior edge of the fibula. The anatomic fibular tunnel exit was located 12.89 (±2.35) mm below the tip of the fibular head. Arthroscopic fibular tunnel placement was reliable in all cases. Instead, in five out of the eight cases with open surgery, the fibular tunnel crossed the defined safety distance to the closest cortical edge/tibiofibular joint (distance < 8 mm). Reliable soft-tissue and bony landmarks of the fibular head allow arthroscopic anatomic fibular tunnel placement in PLC surgery, which shows a lower risk of tunnel malposition compared with open surgical techniques. Future studies will have to show whether clinical results of arthroscopic PLC reconstruction are in line with this study's technical results. Level III.