Anatomic Tunnel Research Articles

Height and Depth Guidelines for Anatomic Femoral Tunnels in Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

To develop guidelines for femoral tunnel placement based on height and depth on the lateral wall of the notch and to apply these guidelines arthroscopically to show tunnel placements within the anterior cruciate ligament (ACL) femoral insertion site. Twelve cadaveric knees were dissected to define the centers of the femoral ACL attachment and its anteromedial (AM) and posterolateral (PL) bundles. In 90° of flexion, the height and depth of each center were determined relative to the low point on the lateral intercondylar notch. Radiographic grid measurements were made to validate these measurements. Subsequently, the measurement guidelines were applied arthroscopically in 10 new cadaveric knees to evaluate their accuracy for an anatomic single-bundle femoral tunnel. Interobserver reliability analysis was evaluated with the intraclass correlation coefficient. In 90° of flexion, the height of the ACL center was 8.7 ± 0.6mm from the low point of the lateral notch; PL center, 7.2 ± 1.2mm; and AM center, 9.6 ± 1.1mm. Relative to the low point, the ACL center was 1.7 ± 1.7mm posterior, the PL center was 3.4 ± 1.5mm anterior, and the AM center was 4.9 ± 1.7mm posterior (intraclass correlation coefficient, 0.859). Radiographic grid measurements were consistent with the direct measurements. Application of the guidelines arthroscopically with or without the assistance of a 7-mm offset aimer placed all guide pins for tunnels within the femoral ACL footprint, with 90% within 4mm of the ACL center. This study showed in cadaveric knees in 90° of flexion that the center of the ACL can be located on the lateral notch at a height of 8.7 ± 0.6mm from the lowest point and anterior 11.5 ± 1.3mm from the deepest point. How anatomic tunnels can be placed using these measurements was also shown in cadaveric knees. An anatomic femoral tunnel for ACL reconstruction can be placed using height and depth guidelines.

The Lateral Meniscus as a Guide to Anatomical Tibial Tunnel Placement During Anterior Cruciate Ligament Reconstruction.

Purpose: The aim of the study is to show, on an MRI scan, that the posterior border of the anterior horn of the lateral meniscus (AHLM) could guide tibial tunnel position in the sagittal plane and provide anatomical graft position.Method:One hundred MRI scans were analysed with normal cruciate ligaments and no evidence of meniscal injury. We measured the distance between the posterior border of the AHLM and the midpoint of the ACL by superimposing sagittal images.Results:The mean distance between the posterior border of the AHLM and the ACL midpoint was -0.1mm (i.e. 0.1mm posterior to the ACL midpoint). The range was 5mm to -4.6mm. The median value was 0.0mm. 95% confidence interval was from -0.5 to 0.3mm. A normal, parametric distribution was observed and Intra- and inter-observer variability showed significant correlation (p<0.05) using Pearsons Correlation test (intra-observer) and Interclass correlation (inter-observer).Conclusion:Using the posterior border of the AHLM is a reproducible and anatomical marker for the midpoint of the ACL footprint in the majority of cases. It can be used intra-operatively as a guide for tibial tunnel insertion and graft placement allowing anatomical reconstruction. There will inevitably be some anatomical variation. Pre-operative MRI assessment of the relationship between AHLM and ACL footprint is advised to improve surgical planning.Level of Evidence:Level 4.

A radiological comparative study between transtibial & anteromedial portal drilling of femoral tunnel in single bundle anterior cruciate ligament reconstruction: A comparison of four angles

Femoral tunnel drilling for graft insertion is performed by transtibial or transportal technique. AimMain objective of this study was to compare the postoperative anteroposterior and lateral radiographs after arthroscopic ACL reconstruction by transtibial and transportal techniques by measuring four angles. Materials and methodsA retrospective study of 60 patients was conducted, who were further subdivided into two groups containing 30 each. The first group had patients who had undergone arthroscopic ACL reconstruction by transtibial technique and the second group had patients who had undergone ACL reconstruction by transportal technique. Post-operative anteroposterior radiographs (AP) and lateral radiographs of the operated knees were compared. Condylar tunnel (CT) and tunnel screw (TS) angles were measured in AP radiographs and compared. In lateral radiographs, shaft tunnel (ST) and TS angles were measured and compared. ‘Student t-test’ was used in calculating the results. ResultsMean of the angles measured were tabulated and compared. CT angle was noted to be more acute in transportal group (38.4±8.756°) as compared to transtibial group (46.97±12.754°) with a significant ‘p-value’ (0.004). ST angle was noted to be more obtuse in the transportal group (119.57±11.212°) as compared to transtibial group (113.17±12.793°) with a significant ‘p-value’ (0.044).This infers that transportal technique oriented the graft more horizontal as compared to transtibial technique.Tunnel screw angles when compared in AP radiographs showed that transportal technique (5.5±4.644°) had more acute angulation as compared to transtibial group (12.57±8.287°) with a significant ‘p-value’ (<0.001). Same results were obtained when the lateral views were compared between transportal (9.27±8.25°) and transtibial technique (23.73±12.174°) with a significant ‘p-value’ (<0.001). This indicated reduced screw tunnel divergence in transportal technique as compared to transtibial technique. ConclusionTransportal technique results in a more anatomical femoral tunnel placement as compared to transtibial technique.

Comparison of Tibial Tunnel Techniques in Posterior Cruciate Ligament Reconstruction: C-Arm Versus Anatomic Fovea Landmark

To evaluate the accuracy of the posterior cruciate ligament (PCL) fovea landmark against conventional fluoroscopic pin placement retrospectively using 3-dimensional computed tomography (3D CT). This retrospective comparison focused on the tibial tunnel locations determined in consecutive 26 patients using the fluoroscopic imaging technique (group I) and in consecutive 23 patients using the PCL fovea landmark technique without the help of thefluoroscopy (group II) for tibial tunnel formation. The 3D surface-modeled CT images that appropriately located the position of the PCL fovea on the tibial plateau were used. Ratios between total length of the fovea and length of the tunnelcenter from the medial border (coronal) and posterior edge (sagittal) were evaluated. The ratios between sagittal tunnel length and total sagittal length for groups I and II were 35.4% ± 12.2% and 44.1% ± 23.1%, respectively (P= .07). The ratios between the coronal tunnel lengths and total coronal lengths for groups I and II were 47.3% ± 9.2% and 57.3% ± 18.1%, respectively: group II showed a more laterally positioned tibial tunnel than did group I (P= .03). A more laterally located tibial tunnel was produced using the PCL fovea landmark technique. However, the differences in centers were small and probably not clinically relevant. Therefore, the PCL fovea landmark technique might be an alternative method to the fluoroscopic imaging technique for locating the anatomic tibial tunnel during transtibial PCL reconstruction. Level III, retrospective comparative study.

Comparison of Knee Kinematics After Single-Bundle Anterior Cruciate Ligament Reconstruction via the Medial Portal Technique With a Central Femoral Tunnel and an Eccentric Femoral Tunnel and After Anatomic Double-Bundle Reconstruction

Background: Anatomic femoral tunnel placement in anterior cruciate ligament (ACL) reconstruction is considered to be a key to good primary stability of the knee. There is still no consensus on whether a centrally placed single bundle in the anatomical femoral footprint can compare with anatomic double-bundle (DB) reconstruction. Purpose/Hypothesis: The purpose of this study was to determine knee kinematics after single-bundle ACL reconstruction via the medial portal technique using 2 different femoral tunnel positions and to compare results with those of the anatomic DB technique. The hypotheses were that (1) single-bundle reconstruction using the medial portal technique with a centrally placed femoral tunnel relative to the native footprint (SB-central technique) would more closely restore intact knee kinematics compared with the same reconstruction technique with an eccentric femoral tunnel drilled in the anteromedial bundle footprint (SB-AM technique) and (2) DB reconstruction would result in superior kinematics compared with the SB-central technique. Study Design: Controlled laboratory study. Methods: Knee kinematics was examined in 10 fresh-frozen human cadaveric knees using a robotic/universal force-moment sensor system. Kinematics in simulated pivot-shift and 134-N anterior tibial loading tests were determined in different conditions within the same specimen: (1) intact ACL, (2) deficient ACL, (3) SB-AM, (4) SB-central, and (5) DB. Results: All reconstruction techniques significantly reduced anterior tibial translation (ATT) compared with a deficient ACL at 0°, 15°, 30°, 60°, and 90° in the anterior tibial loading test (P < .01, repeated-measures analysis of variance) and at 0°, 15°, and 30° in the simulated pivot-shift test (P < .001). There were no significant differences in the SB-central group and the DB group compared with the intact ACL. Reconstruction in the SB-AM group resulted in significantly increased ATT compared with the intact ACL in near-to-extension angles in both tests (0°, 15°, and 30°; P < .01). SB-central and DB reconstructions both resulted in significantly reduced ATT, in some tests at ≤30°, compared with SB-AM reconstruction (P < .05). No significant differences between the SB-central and DB groups were found (P > .05). Conclusion: The SB-central technique restored intact knee kinematics more closely than did SB-AM reconstruction at time zero. There were no differences in knee kinematics between the DB and SB-central techniques. Clinical Relevance: Anatomic single-bundle ACL reconstruction provides similar knee kinematics as anatomic double-bundle reconstruction.

Inside-Out Antegrade Tibial Tunnel Drilling Through the Posterolateral Portal Using a Flexible Reamer in Posterior Cruciate Ligament Reconstruction

Posterior cruciate ligament (PCL) reconstruction using the transtibial drilling or arthroscopic tibial-inlay technique has a risk of injury to the popliteal neurovascular bundle because a pin is drilled anterior to posterior. Intraoperative fluoroscopy is used to decrease the risk of neurovascular injury. In addition, graft passage in the transtibial technique may be problematic because of a sharp turn when placing the graft into the tibial tunnel, which may damage graft fibers. In the surgical technique described in this report, the posteromedial portal is used for visualization and the posterolateral portal is used for debridement of the PCL tibial footprint and the synovial fold closest to the PCL. A curved guide is placed from the posterolateral portal to the tibial footprint, and a flexible pin is drilled across the tibia. The tibial tunnel is then created using a flexible reamer under direct visualization up to the desired length, and a graft can be positioned in the tibial tunnel through the posterolateral portal. This technique has the potential advantages of decreasing the risk of injury to the popliteal neurovascular bundle (use of anteriorly directed, inside-out drilling), avoiding a sharp turn during graft passage, and allowing accurate and anatomic tibial tunnel placement without intraoperative fluoroscopy.

Radiographic positions of femoral ACL, AM and PL centres: accuracy of guidelines based on the lateral quadrant method.

Femoral tunnel positioning is an important factor in anatomical ACL reconstructions. To improve accuracy, lateral radiographic support can be used to determine the correct tunnel location, applying the quadrant method. Piefer et al. (Arthroscopy 28:872-881, 2012) combined various outcomes of eight studies applying this method to one guideline. The studies included in that guideline used various insertion margins, imaging techniques and measurement methods to determine the position of the ACL centres. The question we addressed is whether condensing data from various methods into one guideline, results in a more accurate guideline than the results of one study. The accuracy of the Piefer's guideline was determined and compared to a guideline developed by Luites et al. (2000). For both guidelines, we quantified the mean absolute differences in positions of the actual anatomical centres of the ACL, AM and PL measured on the lateral radiographs of twelve femora with the quadrant method and the positions according to the guidelines. The accuracy of Piefer's guidelines was 2.4mm (ACL), 2.7mm (AM) and 4.6mm (PL), resulting in positions significantly different from the actual anatomical centres. Applying Luites' guidelines for ACL and PL resulted in positions not significantly different from the actual centres. The accuracies were 1.6mm (ACL) and 2.2mm (PL and AM), which were significantly different from Piefer for the PL centres, and therefore more accurate. Condensing the outcomes of multiple studies using various insertion margins, imaging techniques and measurement methods, results in inaccurate guidelines for femoral ACL tunnel positioning at the lateral view. An accurate femoral tunnel positioning for anatomical ACL reconstruction is a key issue. The results of this study demonstrate that averaging of various radiographic guidelines for anatomical femoral ACL tunnel placement in daily practice, can result in inaccurate tunnel positions. Diagnostic study, Level 1.

Femoral and Tibial Graft Tunnel Parameters After Transtibial, Anteromedial Portal, and Outside-In Single-Bundle Anterior Cruciate Ligament Reconstruction

Background: Anatomic graft tunnel placement is recommended in anterior cruciate ligament (ACL) reconstruction to restore knee joint stability and function. Transtibial (TT), anteromedial portal (AMP), and outside-in (OI) retrograde drilling surgical techniques have been described for tibial and femoral bone tunnel preparation. Purpose/Hypothesis: The purpose of this study was to evaluate the bone tunnel parameters and compare the ability of 3 different surgical techniques to achieve placement of the ACL femoral and tibial bone tunnels at the center of the native ACL femoral and tibial attachment sites. The hypothesis was that tunnel placement using an AMP or OI technique would result in optimized tunnel parameters and more closely reconstruct the center of the native ACL femoral attachment site. Study Design: Cohort study; Level of evidence, 3. Methods: The study population consisted of 100 patients undergoing anatomic single-bundle ACL reconstruction using multiple-stranded hamstring tendon grafts. In group 1 (n = 36), the femoral tunnel was drilled using a TT surgical technique; in group 2 (n = 32), the femoral tunnel was drilled through an AMP; and in group 3 (n = 32), the femoral tunnel was created by use of an OI technique with retrograde drilling. Computed tomography (CT) scans were obtained postoperatively, and characteristics of femoral and tibial tunnel apertures were correlated to femoral and tibial measurement grid systems. The position of the resulting tibial and femoral bone tunnels for each group was compared with the center of the native ACL attachment sites. Results: There were statistically significant differences (P < .05) for the ACL femoral tunnel between the 3 groups with respect to intercondylar height, total tunnel length, graft fixation length, tunnel axis, and tunnel entry angle. Statistically significant differences (P < .05) were found for the ACL tibial tunnel with respect to anteroposterior tunnel position and sagittal tunnel axis between the TT and both the OI and AMP techniques. The OI surgical technique produced more oblique and anatomically correct femoral tunnel apertures and longer femoral tunnel lengths compared with the AMP technique. Both AMP and OI techniques resulted in a more precise replication of intercondylar tunnel depth and height. There was no statistically significant difference for graft fixation length between the AMP and OI techniques. Conclusion: The AMP and OI surgical techniques were superior in positioning the ACL femoral tunnel at the center of the native ACL attachment site compared with the TT technique. An acceptable graft fixation length was obtained for all 3 surgical techniques.

ACL Roof Impingement Revisited

Objectives:Anatomic femoral tunnel placement for single-bundle ACL reconstruction is now well accepted. The ideal location for the tibial tunnel, however, has not been studied extensively. A wide range of anterior to posterior (A-P) tibial tunnel locations are considered acceptable. Biomechanical data suggests that the anterior fibers of the native ACL are more functional. Similarly, ACL grafts placed more anteriorly in the footprint have resulted in improved clinical results in at least one study. However, the concern for intercondylar roof impingement has tempered enthusiasm for a more anterior tibial tunnel placement. Investigations by Howell and others on roof impingement have focused only on the transtibial technique. Our study seeks to characterize intercondylar roof impingement in a 3-D cadaveric model with both transtibial and independent femoral tunnel drilling techniques in the setting of an anteriorly positioned tibial tunnel.Methods:Twelve fresh frozen cadaver knees (six matched pairs) were randomized to either a transtibial or an independent femoral (IF) drilling technique. Tibial guide pins were placed in the anterior half of the ACL tibial footprint following arthroscopic debridement of the native ACL. A fluoroscopic calculation of the tibial guide pin location using the technique described by Staubli was used to ensure a relatively anterior position of the tibial tunnel (Staubli < 35). All efforts were made to place the femoral tunnel anatomically in the center of the footprint. An 8 mm Gore-Tex smoother was passed into the knee to function as a radiopaque surrogate graft, and the knees then underwent computed tomography in maximal extension. Graft-visualized 3D-CT reformatting was used to evaluate for roof impingement by analyzing the Impingement Review Index (IRI) as described by Iriuchishima. Tunnel morphology, knee flexion, and intra-articular graft angles were also recorded.Results:Two grafts (2/6, 33.3 %) in the TT group impinged upon the intercondylar roof and sustained an angular deformity (IRI Type 1) Figure 1. No grafts in the IF group impinged; 4/6 (66.7%) grafts in the IF group touched the roof but did not deflect (IRI Type 2). The average tibial tunnel fluoroscopic Staubli ratio was 31.9 (range 22 - 39). The impinging TT grafts had an average Staubli ratio of 29.4 while the non-impinging TT grafts had more posterior tibial tunnels (Staubli 38). This did not reach statistical significance. All other grafts avoided contact with the roof (IRI Type 3). Two tibial tunnels in the TT group migrated posteriorly more than 6 mm after femoral tunnel drilling, and this may have prevented graft impingement. No significant differences were found between the tibial tunnel locations in the IF group.Conclusion:The independent femoral drilling technique appears to have a low risk for roof impingement in the setting of anterior tibial tunnel positioning, likely because of more favorable graft trajectory afforded by an anatomic femoral tunnel that lies below Blumensaat's line. Roof impingement remains a concern after transtibial ACL reconstruction with a more anterior tibial tunnel. An unintended protective effect may occur during transtibial drilling that expands the tibial tunnel posteriorly. Future clinical studies are planned to develop better recommendations for ACL tibial tunnel placement.

Secure fixation of femoral bone plug with a suspensory button in anatomical anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft

the efficacy and safety of using a suspensory button for femoral fixation in anatomical anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) graft have not been established. The purpose of the current study was to evaluate bone plug integration onto the femoral socket and migration of the bone plug and the EndoButton (EB) (Smith & Nephew, Andover, MA, USA) after rectangular tunnel ACL reconstruction with BPTB autograft. thirty-four patients who underwent anatomical rectangular ACL reconstruction with BPTB graft using EB for femoral fixation and in whom three-dimensional (3D) computed tomography (CT) was performed one week and one year after surgery were included in this study. Bone plug integration onto the femoral socket, bone plug migration, soft tissue interposition, EB migration and EB rotation were evaluated on 3D CT. The clinical outcome was also assessed and correlated with the imaging outcomes. the bone plug was integrated onto the femoral socket in all cases. The incidence of bone plug migration, soft tissue interposition, EB migration and EB rotation was 15, 15, 9 and 56%, respectively. No significant association was observed between the imaging outcomes. The postoperative mean Lysholm score was 97.1 ± 5.0 points. The postoperative side-to-side difference, evaluated using a KT-2000 arthrometer, averaged 0.5 ± 1.3 mm. There were no complications associated with EB use. Imaging outcomes did not affect the postoperative KT side-to-side difference. the EB is considered a reliable device for femoral fixation in anatomical rectangular tunnel ACL reconstruction with BPTB autograft. Level IV, therapeutic case series.

Ultrasound-guided Percutaneous Medial Pinning of Pediatric Supracondylar Humeral Fractures to avoid Ulnar Nerve Injury.

Medial pinning is one of the most controversial aspects of the surgical treatment of supracondylar fractures (SHF) owing to the risk of ulnar nerve injury. To evaluate the safety and usefulness of medial pinning for SHF using ultrasound imaging for ulnar nerve visualization. Fifteen children, with a mean age of 60 months, with displaced SHF were treated with a crossed-pinning configuration after fracture reduction. Intraoperative ultrasound was used to guide medial pin insertion to avoid ulnar nerve injury. Cubital tunnel anatomy was easily identified in all children. All children showed a subluxating ulnar nerve that required elbow extension to about 90º before medial pin insertion. None suffered ulnar nerve dysfunction after using the referred technique. Although technically demanding, ultrasound may be a valuable adjuvant to avoid ulnar nerve injury while performing a medial pinning in pediatric SHF.

Anatomic Placement of the Femoral Tunnels in Double-Bundle Anterior Cruciate Ligament Reconstruction Correlates With Improved Graft Maturation and Clinical Outcomes

To compare maturation of reconstructed graft on second-look arthroscopy and clinical outcomes between 2 groups: the provisional anatomic (PA) group, with both the anteromedial (AM) and posterolateral (PL) femoral tunnels in their anatomic location, and the nonanatomic (NA) group, with either 1 of the 2femoral tunnels beyond its anatomic location after double-bundle anterior cruciate ligament reconstruction. We enrolled 154 patients who underwent 3-dimensional computed tomography scanning and second-look arthroscopy after double-bundle anterior cruciate ligament reconstruction. All of the patients were divided into the PA and NA groups according to the femoral tunnel position determined by the quadrant method. Graft maturation was evaluated with 3 subsections, including integrity, tension, and synovial coverage with revascularization, on second-look arthroscopy. We also compared Lachman test, pivot-shift test, KT-2000 (MEDmetric, San Diego, CA), and International Knee Documentation Committee grades at the last follow-up. Of the 154 patients, 88 were classified as the PA group and 66 as the NA group by the quadrant method. A difference existed between groups for the AM tunnel position but not for the PL tunnel position. The PA group showed a higher graft maturation score (P < .001 for all comparisons) and better results according to the International Knee Documentation Committee knee rating, Lachman test, pivot-shift test, and KT-2000 assessment (P < .001 for all comparisons). The PA group with anatomic femoral tunnel placement showed a higher graft maturation score on second-look arthroscopy, along with better clinical outcomes, than the NA group. There was a significant difference in the AM femoral tunnel position but not in the PL tunnel position between the 2 groups. Level III, retrospective comparative study.

Are Standard Post-Operative Anteroposterior and Lateral Knee Radiographs Predictive of Anatomic Femoral Tunnel Placement in ACL Reconstruction?

Are Standard Post-Operative Anteroposterior and Lateral Knee Radiographs Predictive of Anatomic Femoral Tunnel Placement in ACL Reconstruction?

Evaluating the distance between the femoral tunnel centers in anatomic double-bundle anterior cruciate ligament reconstruction using a computer simulation.

PurposeWe aimed to clarify the distance between the anteromedial (AM) bundle and posterolateral (PL) bundle tunnel-aperture centers by simulating the anatomical femoral tunnel placement during double-bundle anterior cruciate ligament reconstruction using 3-D computer-aided design models of the knee, in order to discuss the risk of tunnel overlap. Relationships between the AM to PL center distance, body height, and sex difference were also analyzed.Patients and methodsThe positions of the AM and PL tunnel centers were defined based on previous studies using the quadrant method, and were superimposed anatomically onto the 3-D computer-aided design knee models from 68 intact femurs. The distance between the tunnel centers was measured using the 3-D DICOM software package. The correlation between the AM–PL distance and the subject’s body height was assessed, and a cutoff height value for a higher risk of overlap of the AM and PL tunnel apertures was identified.ResultsThe distance between the AM and PL centers was 10.2±0.6 mm in males and 9.4±0.5 mm in females (P<0.01). The AM–PL center distance demonstrated good correlation with body height in both males (r=0.66, P<0.01) and females (r=0.63, P<0.01). When 9 mm was defined as the critical distance between the tunnel centers to preserve a 2 mm bony bridge between the two tunnels, the cutoff value was calculated to be a height of 160 cm in males and 155 cm in females.ConclusionWhen AM and PL tunnels were placed anatomically in simulated double-bundle anterior cruciate ligament reconstruction, the distance between the two tunnel centers showed a strong positive correlation with body height. In cases with relatively short stature, the AM and PL tunnel apertures are considered to be at a higher risk of overlap when surgeons choose the double-bundle technique.

Combined Intra- and Extra-articular Reconstruction of the Anterior Cruciate Ligament: The Reconstruction of the Knee Anterolateral Ligament

We present a new technique for the combined intra- and extra-articular reconstruction of the anterior cruciate ligament. Intra-articular reconstruction is performed in an outside-in manner according to the precepts of the anatomic femoral tunnel technique. Extra-articular reconstruction is performed with the gracilis tendon while respecting the anatomic parameters of the origin and insertion points and the path described for the knee anterolateral ligament.

Trans-tibial guide wire placement for femoral tunnel in single bundle anterior cruciate ligament reconstruction.

Background:Femoral tunnel location is of critical importance for successful outcome of ACL reconstruction. The aim was to study the femoral tunnel created by placing free hand guide wire through tibial tunnel, using the toggle of the guide wire in the tibial tunnel to improve femoral tunnel location.Materials and Methods:30 cases of a single bundle quadrupled hamstring graft anterior cruciate ligament reconstruction by trans-tibial free hand femoral tunnel creation is studied in this prospective study. The side to side play of the guide wire in the tibial tunnel was used to improve the tunnel location on femoral wall. The coronal angle of the femoral tunnel was measured on the anteroposterior radiograph. The femoral tunnel location on the lateral radiograph of the knee was recorded according to Amis method. Lysholm scoring was done preoperative and at each follow up. Assessment of laxity was done by Rolimeter (Aircast™) and pivot shift test.Results:The mean coronal angle of the femoral tunnel in postoperative radiograph was 47°. In lateral radiograph, the femoral tunnel was found to be >60% posterior on Blumensaat line in 67% cases (n = 20) and in the 33% cases (n = 10) it was anterior. The mean Lysholm score improved from 74.6 preoperative to 93.17 postoperative with no objective evidence of laxity.Conclusion:The free hand trans-tibial creation of the femoral tunnel leads to satisfactory coronal obliquity, but it is difficult to recreate anatomic femoral tunnel by this method as the tunnel is consistently anterior in the sagittal plane.

Fluoroscopic control allows for precise tunnel positioning in MPFL reconstruction.

In MPFL reconstruction, anatomical graft positioning is required to restore physiological joint biomechanics and patellofemoral stability. Considerable rates of non-anatomical femoral tunnel placement exist. The purpose of this study was to analyse whether intraoperative fluoroscopic control is applicable to reduce variability of femoral tunnel positioning. Femoral tunnel positions of 116 consecutive MPFL reconstructions applying intraoperative fluoroscopic images were analysed. Tunnel positions were determined by two independent observers according to Schöttle's radiographic measurement method. Mean positions, standard deviations and ranges were calculated to determine the variability of the tunnel positions. Interclass correlation coefficient (ICC) was calculated. The mean anterior/posterior distances from the anatomical insertion of the MPFL to the centre of the femoral tunnel were 2.34mm (range 0.0-5.9mm) and 1.7mm (range 0.1-7.3mm, SD 1.3) for proximal/distal deviations; 95.7% (111/116) of femoral tunnel positions were found to be within the anatomical insertion area defined by Schöttle. Interobserver tunnel position measurements were highly reliable (ICC: depth 0.979; height 0.979). The study demonstrates that intraoperative fluoroscopic control is a feasible and effective method that enables to create reproducible and precise anatomical femoral tunnel positions in MPFL reconstruction. Accordingly, the routine use of intraoperative fluoroscopy can be recommended. Furthermore, the results indicate Schöttle's method as a reliable method for intraoperative control and postoperative analysis of femoral tunnel positioning. IV.

Excursion of bone-patella tendon-bone grafts during the flexion–extension movement in anterior cruciate ligament reconstruction: Comparison between isometric and anatomic reconstruction techniques

Background/objectiveThe purpose of this study was to elucidate the biomechanical differences between anterior cruciate ligament (ACL) grafts reconstructed by isometric and anatomic reconstruction techniques, based on their length changes. MethodsOne hundred and thirty-three knees with primary ACL reconstruction using the bone-patellar tendon-bone (BTB) graft were retrospectively identified. Twenty-two knees and 111 knees underwent isometric round tunnel (IRT) ACL reconstruction and anatomic rectangular tunnel (ART) ACL reconstruction, respectively. ResultsAfter femoral-side fixation of the graft in the surgery, the length change of the graft from 120° flexion to full extension was measured by using an isometric positioner at the tibial side. Both reconstructive techniques showed little length change from 120° to ∼20° of flexion, followed by elongation of the graft, until full extension. The amount of length change of the grafts was 1.0 ± 0.7 mm with the IRT technique, and 3.4 ± 0.9 mm with the ART technique. These findings were significantly different, based on the Mann–Whitney U test (p < 0.001). ConclusionThe native ACL has an intrinsic length change of 3–6 mm, and therefore the ART technique may more closely replicate the biomechanical function of the native ACL.

Radiographic study on the tibial insertion of the posterior cruciate ligament

ObjectiveTo establish the radiographic distances from posterior cruciate ligament (PCL) tibial insertions centers to the lateral and medial tibial cortex in the anteroposterior view, and from these centers to the PCL facet most proximal point on the lateral view, in order to guide anatomical tunnels drilling in PCL reconstruction and for tunnel positioning postoperative analysis. Study designControlled laboratory study. MethodsTwenty cadaver knees were evaluated. The PCL's bundles tibial insertions were identified and marked out using metal tags, and the knees were radiographed. On these radiographs, the bundles insertion sites center location relative to the tibial mediolateral measure, and the distances from the most proximal PCL facet point to the bundle's insertion were determined. All measures were calculated using the ImageJ software. ResultsOn the anteroposterior radiographs, the mean distance from the anterolateral (AL) bundle insertion center to the medial tibial edge was 40.68±4.10mm; the mean distance from the posteromedial (PM) bundle insertion center to the medial tibial edge was 38.74±4.40mm. On the lateral radiographs, the mean distances from the PCL facet most proximal point to AL and PM bundles insertion centers were 5.49±1.29mm and 10.53±2.17mm respectively. ConclusionsIt was possible to establish a radiographic pattern for PCL tibial bundles insertions, which may be useful for intraoperative tunnels locations control and for postoperative tunnels positions analysis.

Peripheral neuropathy: surgical approaches simplified for the imagers.

Peripheral nerves traverse through different soft tissue compartments in the upper and lower extremities via specific anatomical tunnels, where they are susceptible to entrapment. Common sites in the upper extremity include carpal tunnel, cubital tunnel and radial tunnel. Common sites in the lower extremity include piriformis, fibular neck, and tarsal tunnel. Compressive peripheral neuropathy can develop in these sites, and are amenable for surgical decompression.