Chhabra, Anikar

Abstract Isolated patellofemoral arthritis is a common debilitating condition in adults older than 40 years of age. Surgical options such as patellofemoral arthroplasty exist for those who failed to respond to nonoperative treatment. However, early patellofemoral arthroplasty techniques often resulted in poor outcomes due to mal‐tracking and malalignment of components. Robotic‐assisted surgery recently has been introduced as an alternative to classic patellofemoral arthroplasty, with the potential to improve the anatomical fit and reproducibility of implant positioning. We present the technique for minimally invasive robotic‐assisted patellofemoral arthroplasty system. Technique Video video See video under supplementary data.

Purpose The purpose of this investigation is to assess the incidence of rotator cuff tears in cases of calcific tendonitis and evaluate for differences in the incidences of rotator cuff tears by magnetic resonance imaging (MRI) between calcific lesions of different morphology, size, or location. Methods This single‐center study involved a retrospective chart review searching for patients from January 2010 to April 2017 with a diagnosis of calcific tendonitis of the shoulder based on review of all MRI reads done on patients with shoulder pain. Anteroposterior radiographic and MRI studies were reviewed by a musculoskeletal radiologist to assess calcific tendonitis morphology, size, distance from cuff insertion, and any rotator cuff tear. An additional radiologist evaluated calcific tendonitis size, morphology, and location to evaluate the reliability of these variables. Results In the final cohort of 318 shoulders with calcific tendonitis, the incidence of concomitant rotator cuff tears was 56%. Of all 177 tears, 164 (93%) were partial‐thickness and 13 (7%) were complete. Type III calcification morphology (cloudy with soft contour) was most frequently associated with rotator cuff tears and demonstrated an increased odds of tear by a factor of 1.8 (CI 95% 1.1‐2.9).There was no statistical difference regarding calcification size or location prognosticating rotator cuff tears or tear thickness. Intraclass correlation coefficients for calcification size, morphology, and location were 0.78, 0.30, and 0.50, respectively. Conclusions The incidence of rotator cuff tears in cases of calcific tendonitis in this cohort of patients who underwent MRI is higher than previously reported. Cloudy‐appearing calcified lesions showed a significant association with rotator cuff tears with an odds ratio of 1.8. Specific locations or sizes of calcified lesions do not appear to be reliable factors to predict concomitant rotator cuff tears. Interobserver agreement for these radiographic variables ranged from fair to substantial and prompt a cautious interpretation of these results. Level of Evidence IV Retrospective Case Series.

Purpose To define a distraction distance (pull length) cut‐off that would differentiate those patients with hip microinstability and those without the disorder, called the Pull‐Out Test. Methods In total, 100 consecutive patients undergoing hip arthroscopy were included in the study. Patients were separated into a hip microinstability group (HMI) and non‐hip microinstability group (NHI) based on the results of Beighton's score, the abduction–extension–external rotation test, hip extension–external rotation examination, and the prone instability test. Inclusion criteria were patients with an magnetic resonance imaging‐proven labral tear who did not respond to conservative treatment and underwent hip arthroscopy. Exclusion criteria included those patients undergoing revision hip arthroscopy, had a previous surgery on the ipsilateral hip, or had severe arthritis in the hip. The Pull‐Out Test was performed before surgery with the hip in 30° of abduction and the foot in 30° of external rotation. A blinded examiner places gross axial traction on the leg until a firm end point is reached. The distraction distance between the femoral head and acetabulum is the pull length. Results In total, 32 patients made up the HMI group whereas 68 patients were in the NHI group. The average pull length for the NHI group was 0.9 ± 0.1 cm and 1.7 ± 0.4 cm for the HMI group ( P < .001). Subtracting the standard deviation from the HMI group average, when defined a cut off for hip microinstability as 1.3 cm. Using this value, we found the Pull‐Out Test to have a sensitivity of 0.91 and specificity of 0.96. The positive predictive value for the Pull Test was 0.91 and the negative predictive value 0.97. Conclusions The Pull‐Out Test is a useful test in identifying and confirming the presence of hip microinstability in patients undergoing hip arthroscopy. A pull‐length of 1.3 cm or greater is consistent with the presence of microinstability with a specificity of 94% and a sensitivity of 96%. Level of Evidence Level IV, diagnostic, case‐control study.

Abstract Arthroscopy is currently the gold standard for diagnosing intra‐articular knee pathology. Magnetic resonance imaging (MRI) can be a clinical adjunct for diagnosis; however, it is not without its shortcomings. Although highly accurate, even advanced imaging misdiagnoses the condition in 1 in 14 patients with regard to anterior cruciate ligament pathology. Previous studies have indicated that MRI fails to identify meniscal pathology when one exists in 1 of every 10 cases, and diagnoses pathology when pathology truly does not exist in 1 of every 5 patients. In‐office arthroscopy offers an alternative to formal diagnostic arthroscopy, with reduced cost and risk of complications. This is a technique article that discusses the use of small‐bore needle arthroscopy in the office setting. Technique Video video See video under supplementary data.

Abstract Studies continue to demonstrate the importance of the anterolateral ligament (ALL) as a secondary restraint in rotational stability of the knee. No clinical exam exists to reliably test the ALL. Advanced imaging allows the surgeon to reliably identify the ALL as an independent structure of the lateral knee. This technique paper provides a reproducible method for identification of the ALL on 3T magnetic resonance imaging based on previously conducted cadaveric dissections of the ligament. Technique Video video See video under supplementary data.