Cree M. Gaskin

Anatomic Femoral Tunnel Drilling in Anterior Cruciate Ligament Reconstruction Use of an Accessory Medial Portal Versus Traditional Transtibial Drilling

Background: During anatomic anterior cruciate ligament (ACL) reconstruction, we have found that the femoral footprint can best be visualized from the anteromedial portal. Independent femoral tunnel drilling can then be performed through an accessory medial portal, medial and inferior to the standard anteromedial portal. Purpose: To compare the accuracy of independent femoral tunnel placement relative to the ACL footprint using an accessory medial portal versus tunnel placement with a traditional transtibial technique. Study Design: Controlled laboratory study. Methods: Ten matched pairs of cadaveric knees were randomized such that within each pair, one knee underwent arthroscopic transtibial (TT) drilling, and the other underwent drilling through an accessory medial portal (AM). All knees underwent computed tomography (CT) both preoperatively and postoperatively with a technique optimized for ligament evaluation (80 keV with maximum mAs). Computed tomography was performed with a dual-energy scanner. Commercially available third-party software was used to fuse the preoperative and postoperative CT scans, allowing anatomic comparison of the ACL footprint to the drilled tunnel. The ACL footprint was marked in consensus by an orthopaedic surgeon and a musculoskeletal radiologist and then compared with the tunnel aperture after drilling. The percentage of tunnel aperture contained within the native footprint as well as the distance from the center of the tunnel aperture to the center of the footprint was measured. Results: The AM technique placed 97.7% ± 5% of the tunnel within the native femoral footprint, significantly more than 61.2% ± 24% for the TT technique (P = .001). The AM technique placed the center of the femoral tunnel 3.6 ± 1.2 mm from the center of the native footprint, significantly closer than 6.0 ± 1.9 mm for the TT technique (P = .003). Conclusion: This study demonstrates that use of an accessory medial portal will facilitate more accurate placement of the femoral tunnel in the native ACL femoral footprint. Clinical Relevance: More accurate placement of the femoral tunnel in the native ACL femoral footprint should improve the ability to achieve more anatomic positioning of the ACL graft.

Preliminary results of a novel single-stage cartilage restoration technique: Particulated juvenile articular cartilage allograft for chondral defects of the patella

PURPOSE To evaluate outcomes and magnetic resonance imaging (MRI) findings after use of particulated juvenile cartilage for the treatment of focal Outerbridge grade 4 articular cartilage defects of the patella. METHODS From 2007 to 2011, 16 patients (2 bilateral) underwent a novel single-stage articular cartilage restoration procedure using particulated juvenile articular cartilage allograft. We enrolled 15 knees (13 patients) in this study. The mean age at surgery was 26.4 ± 9.1 years, and the mean postoperative follow-up was 28.8 ± 10.2 months. A musculoskeletal radiologist evaluated each knee with postoperative MRI for the International Cartilage Repair Society cartilage repair assessment score, graft hypertrophy, bony changes around the graft, and percent fill of the defect. All patients also completed the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation, and Kujala clinical outcome survey (scale, 0 to 100), as well as the Tegner activity scale and visual analog pain scale (scale, 0 to 10). RESULTS The mean International Cartilage Repair Society cartilage repair assessment score on MRI was 8.0 ± 2.8, a nearly normal assessment. Of 15 knees, 11 (73%) were found to have normal or nearly normal cartilage repair. Three patients had mild graft hypertrophy whereas 2 had gross graft hypertrophy, 2 of whom required arthroscopic debridement because of symptoms. The mean fill of the defect at follow-up was 89% ± 19.6%, with 12 of 15 knees (80%) showing at least 90% defect coverage. The mean clinical outcome score at follow-up was 73.3 ± 17.6 for the International Knee Documentation Committee evaluation, and the mean scores for each subdomain of the Knee Injury and Osteoarthritis Outcome Score were as follows: 84.2 ± 14.2 for pain, 85.0 ± 12.3 for symptoms and stiffness, 88.9 ± 12.9 for activities of daily living, 62.0 ± 25.1 for sports and recreation, and 60.8 ± 28.6 for quality of life. The median score for the Kujala survey was 79 (range, 55 to 99). The median score on the Tegner activity scale was 5 (range, 3 to 9), and the mean score on the visual analog scale was 1.9 ± 1.4, indicating minimal pain. CONCLUSIONS Preliminary results suggest that cartilage restoration using particulated juvenile articular cartilage allograft offers a viable option for patients with focal grade 4 articular cartilage defects of the patella.

The Effects of Extra-articular Starting Point and Transtibial Femoral Drilling on the Intra-articular Aperture of the Tibial Tunnel in ACL Reconstruction

Background The recent emphasis on more horizontal femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstructions requires placing a femoral tunnel lower on the lateral wall of the notch. Some surgeons have advocated moving the starting point of the tibial tunnel farther medial to achieve this more horizontal tunnel. Purpose To compare tibial tunnel aperture changes with transtibial femoral tunnel drilling. Study Design Controlled laboratory study. Methods Twenty match-paired cadaveric knees (10 specimens) were randomized into 2 groups with equal right and left knee distribution. Ten of the knees underwent tibial tunnel drilling from a medial starting point (group 1), and the corresponding opposite knee of each cadaveric specimen had the tibial tunnel drilled from a central starting point (group 2). Computerized tomography (CT) with thin slices and 3-dimensional reconstruction was used to obtain the dimensions of the apertures, area of the apertures, angles of the tunnels, and location of the starting point and ending point of the tunnels. We also determined the location of the femoral tunnels in the notch for each of the groups. The 10 knees with medial starting points underwent transtibial femoral tunnel drilling and were restudied with CT to evaluate changes in tibial tunnel characteristics. The 10 knees with central starting points underwent femoral drilling from an anteromedial arthroscopic portal. Results Central tibial tunnels were slightly larger than medial tibial tunnels before femoral drilling (106.3 mm3 vs 92.4 mm3). After femoral drilling through the medial tunnels, the apertures were larger than the central tibial apertures (118.6 mm3 vs 106.3 mm3). Medial tibial tunnels resulted in an intra-articular aperture that was farther from the tibial tubercle (43.1 mm vs 16.3 mm), farther from the medial tibial plateau (38.3 mm vs 32.2 mm), and more acute in the coronal plane (50.4° vs 79.3°). Medial tibial tunnels resulted in an intra-articular aperture that was closer to the anterior edge of the tibia (22.6 mm vs 29.6 mm) but with a less acute sagittal plane angle (82.5° vs 54.5°). The average clock-face measurement on the femur was 10:40 (±14 minutes) for the medial starting point and 10:14 (±14 minutes) for the central starting point (drilled from an anteromedial arthroscopic portal) (P = .0016). Conclusion We observed significantly increased tibial aperture size and shape after transtibial femoral drilling with a medial tibial starting point. Medial tibial tunnels, compared with more central tunnels, resulted in a more acute tibial tunnel in the coronal plane and less acute tibial tunnels relative to the sagittal plane. Medial tibial tunnels started farther from the tibial tubercle but ended farther from the medial joint line and closer to the anterior edge of the tibia in comparison to central tunnels Clinical Relevance Femoral tunnel placements may be best accomplished using a technique other than transtibial drilling through a medial tibial tunnel. Tibial tunnel angle, intra-articular position, and femoral tunnel placement are affected by the choice of extra-articular starting position.

Anomalies of the long head of the biceps brachii tendon: clinical significance, MR arthrographic findings, and arthroscopic correlation in two patients

Two patients with clinically relevant anomalies of the long head of the biceps brachii tendon (LHBT) are presented with MR arthrography and surgical correlation. Such variations in the LHBT can mimic tears of the tendon itself or the adjacent superior labrum both on MR arthrography and at surgery. MR arthrographic features are recognizable and allow for correct prospective diagnosis, possibly averting unnecessary surgery. Although further study is needed, patients with these anomalies may be at increased risk for developing shoulder instability.

Anatomic Femoral Tunnels in Posterior Cruciate Ligament Reconstruction Inside-Out Versus Outside-In Drilling

Background: During posterior cruciate ligament (PCL) reconstruction, the placement and orientation of the femoral tunnel is critical to postoperative PCL function. Purpose: To compare the ability of outside-in (OI) versus inside-out (IO) femoral tunnel drilling in placing the femoral tunnel aperture within the anatomic femoral footprint of the PCL, and to evaluate the orientation of the tunnels within the medial femoral condyle. Study Design: Controlled laboratory study. Methods: Ten matched pairs of cadaver knees were randomized such that within each pair, 1 knee underwent arthroscopic OI drilling and the other underwent IO drilling. All knees underwent computed tomography (CT) both pre- and postoperatively with a technique optimized for ligament evaluation (80 keV with maximum mAs). Commercially available third-party software was used to fuse the pre- and postoperative CT scans, allowing comparison of the PCL footprint to the drilled tunnel. The percentage of tunnel aperture contained within the native footprint, as well as the distance from the center of the tunnel aperture to the center of the footprint, were measured. In addition, the orientation of the tunnels in the coronal and axial planes was evaluated. Results: The OI technique placed 70.4% ± 23.7% of the tunnel within the native femoral footprint compared with 79.8% ± 16.7% for the IO technique (P = .32). The OI technique placed the center of the femoral tunnel 4.9 ± 2.2 mm from the center of the native footprint compared to 5.3 ± 2.0 mm for the IO technique (P = .65). The femoral tunnel angle in the coronal plane was 21.0° ± 9.9° for the OI technique and 37.0° ± 10.3° for the IO technique (P = .002). The tunnel angle in the axial plane was 27.3° ± 4.8° for the OI technique and 39.1° ± 11.5° for the IO technique (P = .01). Conclusion: This study demonstrates no difference in the ability of the OI and IO techniques to place the femoral tunnel within the PCL femoral footprint during PCL reconstruction. With the technique parameters used in this study, the IO technique created femoral tunnels with a more vertical and anterior orientation than the OI technique. Clinical Relevance: Either technique can be used to place the femoral tunnel within the anatomic footprint. Consideration should be given to tunnel orientation following each technique, and what effect it has on graft bending angles, as these characteristics may affect graft strain and, ultimately, graft failure. In this regard, the IO technique likely produces gentler graft bending angles.

Assessment of scaphoid viability with MRI: a reassessment of findings on unenhanced MR images.

OBJECTIVE The purpose of this article is to evaluate the accuracy of unenhanced T1-weighted MR images in predicting the vascular status of the proximal pole of the scaphoid in patients with chronic scaphoid fracture nonunions. MATERIALS AND METHODS A database search identified 29 patients with chronic scaphoid nonunions who underwent a preoperative MRI examination and intraoperative assessment of scaphoid viability from 2004 to 2009. T1-weighted MR images were evaluated by two musculoskeletal radiologists. If the proximal pole demonstrated diffusely decreased T1-weighted signal (less than or equal to that of skeletal muscle), the patient was placed in a moderate-to-high risk for avascular necrosis (AVN) category. Otherwise, the patient was placed in a viable-to-low risk for AVN category. Scaphoid viability or necrosis was diagnosed intraoperatively depending on whether punctate bleeding was present. After the patients were classified according to the T1-weighted appearance, the appearance on STIR images was recorded. RESULTS There were 29 patients (25 male) with a mean age of 21 years. When we compared the MRI results, using only the T1-weighted images, with the surgical findings, unenhanced MRI had a sensitivity, specificity, and accuracy of 55%, 94%, and 79%, respectively, for diagnosing AVN. Increased proximal pole STIR signal was noted with similar frequencies in patients with and without AVN. CONCLUSION T1-weighted unenhanced MRI is an acceptable alternative to delayed contrast-enhanced MRI in the preoperative assessment of the vascular status of the proximal pole of the scaphoid in patients with chronic fracture nonunions. STIR images were not beneficial in determining proximal pole viability.

Tibial tunnel placement accuracy during anterior cruciate ligament reconstruction: independent femoral versus transtibial femoral tunnel drilling techniques

PURPOSE This study aimed to compare the accuracy of tibial tunnel placement using independent femoral (IF) versus transtibial (TT) techniques. METHODS Ten matched pairs of cadaveric knees were randomized so that one knee in the pair underwent arthroscopic TT drilling of the femoral tunnel and the other underwent IF drilling through an accessory medial portal. For both techniques, an attempt was made to place the femoral and tibial tunnels as close to the center of the respective anterior cruciate ligament (ACL) footprints as possible. Preoperative and postoperative computed tomography using a technique optimized for ligament evaluation allowed comparison of the anatomic ACL tibial footprint to the tibial tunnel aperture. The percentage of tunnel aperture contained within the native footprint, as well as the distance from the center of the tunnel aperture to the center of the footprint, was measured. Additionally, graft obliquity relative to the tibial plateau was evaluated in the sagittal plane. RESULTS The percentage of tibial tunnel aperture contained within the native footprint averaged 71.6% ± 17.2% versus 52.1% ± 23.4% (P = .04) in the IF and TT groups, respectively. The distance from the center of the footprint to the center of the tibial tunnel aperture was 3.50 ± 1.6 mm and 4.40 ± 1.7 mm (P = .27) in the IF and TT groups, respectively. TT drilling placed 6 of 10 tunnels posterior to the center of the footprint versus 3 of 10 tunnels in IF drilling. The graft obliquity angles were 54.8° in TT specimens and 47.5° in IF specimens (P = .09). CONCLUSIONS This study adds to the literature suggesting that TT drilling with an 8-mm reamer has deleterious effects on tibial tunnel aperture and position. IF drilling, which does not involve repeated reaming of the tibial tunnel, is associated with the placement of a higher percentage of the tunnel aperture within the native tibial footprint. There was not a significant difference between the IF and TT techniques in their ability to place the center of the tibial aperture near the center of the footprint or in graft obliquity. CLINICAL RELEVANCE ACL reconstruction has continued to evolve in an attempt to restore the functional anatomy and biomechanical behavior of the knee. Tibial tunnel characteristics-such as location, aperture topography, and tunnel obliquity-are important factors to consider in ACL reconstruction. This study compares tibial tunnels after IF and TT techniques.

Imaging characteristics of angiomatoid fibrous histiocytoma of bone

We present the first report of a patient with angiomatoid fibrous histiocytoma of bone in the radiology literature. This tumor initially eluded diagnosis due to its similarities with chronic hematoma and aneurysmal bone cyst. Only two cases of angiomatoid fibrous histiocytoma have been reported in the radiology literature and both of these lesions were in the soft tissues. The fairly distinctive findings in our patient of multiple large cystic chambers with fluid-fluid levels are similar to the findings in the two soft tissue case reports, suggesting that imaging may be used to suggest this specific diagnosis regardless of location, especially in the clinical setting of unexplained hematoma or anemia. Mention of this diagnosis in the radiology report may aid in the final diagnosis at pathology, because special techniques, including fluorescent in situ hybridization, must be applied in order to fully evaluate for the diagnosis.

MR Arthrography: Impact of Steroids, Local Anesthetics, and Iodinated Contrast Material on Gadolinium Signal Intensity in Phantoms at 1.5 and 3.0 T

PURPOSE To determine if gadolinium signal intensity at direct magnetic resonance (MR) arthrography is affected by the addition of steroids, anesthetics, or iodinated contrast material. MATERIALS AND METHODS This study did not require approval by the institutional review board because no patients or patient data were involved. An in vitro study was performed to evaluate various concentrations of three gadolinium contrast agents (gadopentetate dimeglumine, gadobenate dimeglumine, and gadofosveset trisodium) diluted in either saline or iodinated contrast material (50% and full-strength iohexol 300). Three steroids (betamethasone, triamcinolone, and methylprednisolone) and three local anesthetics (lidocaine, ropivacaine, and bupivacaine) were added to solutions in clinical doses. T1-weighted fat-suppressed MR imaging sequences were performed in phantoms at 1.5 and 3.0 T. Signal intensities were measured. All experiments were repeated in full for a total of three replications each. The data were analyzed by using two-way factorial analysis of variance. RESULTS Dilution of gadolinium into iohexol reduced the signal intensity in all samples compared with dilution in saline alone. Peak signal intensities were at 0.625 and 1.25 mmol/L of gadolinium in iohexol at both magnet strengths. At 1.5 T, the addition of steroids and anesthetics to the saline solutions had no impact on the signal intensity curves, with the peak signal intensity at gadolinium concentrations of 2.5 and 1.25 mmol/L. At 3.0 T, the addition of steroids and anesthetics had minimal effect on signal intensity curves, with the peak signal intensity at 1.25 mmol/L of gadolinium. CONCLUSION The addition of steroids and/or anesthetics to gadolinium solutions for MR arthrography does not substantially impact signal intensity. When gadolinium is diluted into a 50% or greater strength of iohexol, the signal intensity curve shifts so that the maximum signal intensity is obtained with lower gadolinium concentrations (0.625-1.25 mmol/L).

Magnetic resonance imaging appearance of scurvy with gelatinous bone marrow transformation

Scurvy is a lethal but treatable disease that is rare in industrialized countries. Caused by vitamin C deficiency, it is most prevalent in persons of low socioeconomic status and smokers. Low levels of circulating vitamin C result in poor collagen fiber formation that, in turn, leads to demineralized bones, microfractures, and poor healing. Here we report a case of scurvy in a 5-year-old boy with normal radiographs in whom initial concern for leukemia based upon magnetic resonance imaging and clinical presentation led to a bone marrow biopsy revealing gelatinous transformation.