Arthroscopic image distortion-part I: the effect of lens and viewing angles in a 2-dimensional in vitro model

The relevance of knee arthroscopy photographs in medicolegal proceedings

PURPOSE

Whether photographs included in the operative report of knee arthroscopies can make the surgeon liable in the event of a legal investigation remains unknown. The main objective of this study was to establish inter-observer reliability in determining the presence or absence of lesions of the cartilage, meniscus and anterior cruciate ligament (ACL). Secondary objective was to assess the inter-observer reliability in classifying lesions.

METHOD

A retrospective observational study was conducted in a continuous serie of 60 patients who underwent knee arthroscopy from the same operator. The photographs of each patient's operative report were presented separately to three experts, blinded to each other. Each expert had to decide on the presence or absence of injuries to the following structures: meniscal, cartilage and ACL and then, classify it. Primary and secondary endpoints were evaluated using the Fleiss' kappa index.

RESULTS

Inter-observer reliability for lesion detection was between 0.4 and 0.61 for all structures with three exceptions: for cartilage, it was low (0.15) at the lateral tibial plateau and poor (-0.01) at the external condyle. On the contrary, the concordance was almost perfect (0.8) for the ACL. For classifying cartilaginous and meniscal lesions, inter-observer reliability was poor (from 0.03 to 0.14), except for at the lateral meniscus (0.65).

CONCLUSION

Inter-observer reliability of arthroscopic knee diagnoses is poor when photographs alone are used. In the event of a legal investigation following knee arthroscopy, the photographs included in the operative report should not be used alone to hold the surgeon liable.

The morphology of the tibial footprint of the anterior cruciate ligament changes with ageing from oval/elliptical to C-shaped

PURPOSE

To further the current understanding of the modifications of the morphology of the ACL tibial footprint in healthy knees during the ageing process. The hypothesis is that there are differences in the morphology of the ACL tibial footprint between the cadavers of the young and elderly due to a degenerative physiological process that occurs over time.

METHODS

The tibial footprint of the ACL was dissected in 64 knee specimens of known gender and age. They were divided into four groups by age and gender, setting 50 years of age as the cut-off point. Three observers analyzed the tibial footprint dissections and the shape was described and classified.

RESULTS

The knees from the cadavers of males older than 50 years of age presented a "C" morphology in 85% of the cases. In the group of males aged less than 50 years, an oval/elliptical morphology was found in 85.7% of the cases. In the group of women over 50 years-old, the "C" morphology was observed in 82.3% of the cases. In women under the age of 50, the oval/elliptical morphology was found in 84.6% of the cases. A significant difference was observed between the prevalence rates of the morphologies of the younger and older groups (p < 0.001 for both genders). However, no differences were observed between males and females of the same age group (n.s.).

CONCLUSIONS

The morphology of the tibial footprint of the ACL presents significant variations with ageing. It can go from an oval/elliptical shape to a "C" shaped morphology. The results of this work make for an advance in the individualization of ACL reconstruction based on the age and the specific morphology of the tibial footprint.

Comparison of needle arthroscopy, traditional arthroscopy, and computed tomography for the evaluation of medial coronoid disease in the canine elbow

OBJECTIVE

To evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology.

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Dogs (n = 17) presented for evaluation of elbow dysplasia.

METHODS

For each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated.

RESULTS

Images of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P < .001). Still images of TAR and SNAR had comparable concordance for cartilage score (0.80 and 0.77, respectively) and medial compartment pathology (0.80 and 0.73, respectively).

CONCLUSION

Still images of NAR, STAR, and CT had similar diagnostic value to identify MCP fissures. Still images of TAR was superior to SNAR and CT to identify MCP fragments.

CLINICAL SIGNIFICANCE

The diagnostic accuracy of SNAR varied on the basis of the coronoid lesion being evaluated.

The novel arthroscopic subscapular quadriceps tendon-bone sling procedure provides increased stability in shoulder cadavers with severe glenoid bone loss

PURPOSE

Treatment of anterior glenoid bone loss in patients with recurrent anterior shoulder instability is a challenge. The subscapular sling method with quadriceps tendon bone (QTB) graft is a modification of the subscapular sling with a semitendinosus (ST) graft. The aim of the study was to test the biomechanical stability of the QTB sling procedure in human shoulder cadavers with severe anterior glenoid bone loss.

METHODS

Fourteen cadaveric shoulders were tested with a force-moment-guided robot in three conditions: physiologically intact, anterior glenoid bone resection, and the subscapular sling procedure with a QTB graft. Joint stability was measured in anterior, anterior inferior and inferior directions in four glenohumeral joint positions: 0° and 60° of glenohumeral abduction, with each at 0° and 60° of external rotation. Maximum external rotation was measured at 0° and 60° glenohumeral abduction. Computer tomography scans were obtained preoperatively to plan the glenoid bone resection, as well as postoperatively to calculate the proportion of the glenoid bone actually resected.

RESULTS

Significantly decreased translations were observed in the shoulders with the QTB sling compared to the intact joint and the glenoid bone loss model. No significant differences in maximum external rotation were observed between the three different conditions.

CONCLUSION

This biomechanical study revealed a significant stabilizing effect of the arthroscopic subscapular QTB graft sling procedure in human shoulder cadavers without compromising external rotation. Clinical trials may reveal the usefulness of this experimental method.

How to Achieve an Accurate Anatomical Femoral Tunnel Technique in ACL Reconstruction in the Early Years of Your Consultancy? Femoral Offset Aimer Technique: Consistent and Reproducible Technique

Femoral tunnel malposition is the most common reason for failure of primary anterior cruciate ligament reconstruction. There are several methods to identify the anatomical location of femoral footprint. Femoral offset aimer technique is one such technique which is easy to use and reliable. It is an ideal technique for junior and inexperienced surgeons to recreate the femoral tunnel in its anatomical footprint. The senior author (P.E.) has been using this technique for 30 consecutive cases in his first year of independent practice during his consultancy without any major intraoperative complications. The author describes this technique in this article with tips and tricks which will especially guide the junior and inexperienced surgeons to avoid running into intraoperative problems while drilling the femoral tunnel.

The 45 degrees arthroscope: A forgotten scope in knee surgery

The majority of knee arthroscopic procedures are performed with 30° scope while the 70° arthroscope is mainly used for surgery of posterior compartments. In the arthroscopic armamentarium, another scope, unknown to many surgeons, is also available: the 45° arthroscope. His field of view provides a wider intraoperative view than that of a 30° scope without the characteristic blind spot of a 70° scope. Therefore, the surgeon's orientation is not compromised. because the optic has always an element of forward vision. With these advantages, the 45° scope can be used in all knee surgical procedures without the need for having two scopes sterilized on the surgical table with less risk of contamination and less surgical time. The 45° scope may also be valuable for the arthroscopic surgery of other joints with the same advantages.

Accuracy of radiographic determination of the posterior femoral wall integrity in anterior cruciate ligament reconstruction

Objective

To evaluate the accuracy of radiographs in determining integrity of the posterior femoral cortex following ACL reconstruction.

Methods

Fifty adult volunteers undergoing primary arthroscopic transtibial ACL reconstructions were prospectively enrolled into this study. Plain radiographs and fine-cut CT of the operative knee were obtained post-operatively. Three blinded orthopaedic surgeons were asked to measure the distance from the femoral tunnel to the posterior cortex on lateral radiographs. Inter/intra-observer reliabilities were assessed with the interclass correlation coefficient. The true measurement of the posterior wall was determined on CT. For each, a measurement was made at the aperture, 5 mm, and 10 mm along the tunnel. Plain radiographic measurements were compared to the CT measurement of back wall using a paired t-test.

Results

All measurements made on the lateral radiograph were significantly different from those from the respective CT scans for each surgeon (p < 0.0001) at all points. When radiographic measurements were compared to CT at the level of the intra-articular aperture, 29 subjects showed violation of the posterior cortex, with only one being identified on plain films. At 5 mm, 7 subjects demonstrated posterior cortical violation, and none were identified on lateral radiographs. The posterior cortex remained intact in all cases at 10 mm.

Conclusion

Lateral radiographs of the knee are insufficient for evaluation of the posterior cortical integrity following primary ACL reconstruction. Direct visualization of the femoral tunnel remains the gold standard for evaluation of the posterior wall and may be supplemented by CT scan if there remains concern over graft fixation.

Variation in the shape of the tibial insertion site of the anterior cruciate ligament: classification is required

PURPOSE

To propose a classification system for the shape of the tibial insertion site (TIS) of the anterior cruciate ligament (ACL) and to demonstrate the intra- and inter-rater agreement of this system. Due to variation in shape and size, different surgical approaches may be feasible to improve reconstruction of the TIS.

METHODS

One hundred patients with a mean age of 26 ± 11 years were included. The ACL was cut arthroscopically at the base of the tibial insertion site. Arthroscopic images were taken from the lateral and medial portal. Images were de-identified and duplicated. Two blinded observers classified the tibial insertion site according to a classification system.

RESULTS

The tibial insertion site was classified as type I (elliptical) in 51 knees (51 %), type II (triangular) in 33 knees (33 %) and type III (C-shaped) in 16 knees (16 %). There was good agreement between raters when viewing the insertion site from the lateral portal (κ = 0.65) as well as from the medial portal (κ = 0.66). Intra-rater reliability was good to excellent. Agreement in the description of the insertion site between the medial and lateral portals was good for rater 1 and good for rater 2 (κ = 0.74 and 0.77, respectively).

CONCLUSION

There is variation in the shape of the ACL TIS. The classification system is a repeatable and reliable tool to summarize the shape of the TIS using three common patterns. For clinical relevance, different shapes may require different types of reconstruction to ensure proper footprint restoration. Consideration of the individual TIS shape is required to prevent iatrogenic damage of adjacent structures like the menisci.

LEVEL OF EVIDENCE

III.

Posterior Wall Blowout in Anterior Cruciate Ligament Reconstruction: A Review of Anatomic and Surgical Considerations

Violation of the posterior femoral cortex, commonly referred to as posterior wall blowout, can be a devastating intraoperative complication in anterior cruciate ligament (ACL) reconstruction and lead to loss of graft fixation or early graft failure. If cortical blowout occurs despite careful planning and adherence to proper surgical technique, a thorough knowledge of the anatomy and alternative fixation techniques is imperative to ensure optimal patient outcomes. This article highlights anatomic considerations for femoral tunnel placement in ACL reconstruction and techniques for avoidance and salvage of a posterior wall blowout.

Arthroscopic image distortion-part II: the effect of lens angle and portal location in a 3D knee model

PURPOSE

Distortion in arthroscopic views can interfere with accurate graft placement in ACL reconstruction, yet the effect of arthroscopic lens angle and portal location on image distortion is unknown. The purpose of this study was to quantify the image distortion resulting from the use of angulated arthroscope lenses through multiple portals, thereby identifying the optimal parameters to minimize distortion.

METHODS

A uniform grid of dots was attached to the lateral wall of the intercondylar notch of a Sawbones(®) knee model. The inferior half of the lateral wall was divided equally along the distoproximal axis into three regions-shallow, central, and deep. Each region was imaged using five different arthroscopic configurations [0° arthroscope through anteromedial (AM) portal, 30° arthroscope through AM and anterolateral (AL) portals, 70° arthroscope through AM and AL portals]. For each configuration, the differences in magnification and deformity ratios between the three regions were calculated.

RESULTS

Less than 100 % of central region magnification was observed in the deep region, while more than 100 % was found in the shallow region. The AL approach produced larger magnification errors in the shallow region, as compared to the AM approach. Deformity ratios less than 100 % were found with both 0° and 30° arthroscopes, whereas deformity ratios exceeding 100 % were found with 70° arthroscopes.

CONCLUSIONS

The least distorted and the most consistent image of the femoral ACL insertion is provided through the AM portal using either a 30° or 70° arthroscope lens. Surgeons should carefully select the arthroscope and portal to minimize image distortion and ensure accurate surgical procedure.