Citations

AbstractControl of knee motion in small animal models is necessary to study the effect of mechanical load on the healing process. This can be especially challenging in mice, which are being increasingly used for various orthopedic reconstruction models. We explored the feasibility of botulinum toxin (Botox; Allergan, Dublin, Ireland) paralysis and a newly designed external fixator to restrict motion of the knee in mice undergoing anterior cruciate ligament (ACL) reconstruction. Nineteen C57BL/6 mice were allocated to two groups: (1) Botox group (n = 9) and (2) external fixator group (n = 10). Mice in Botox group received two different doses of Botox: 0.25 unit (n = 3) and 0.5 unit (n = 6). Injection was performed 72 hours prior to ACL reconstruction into the quadriceps, hamstring, and calf muscles of the right hind leg. Mice in external fixator group received an external fixator following ACL reconstruction. Mice were monitored for survival, tolerance, and achievement of complete knee immobilization. All mice were meant for sacrifice on day 14 postoperatively. No perceptible change in gait was observed with 0.25 unit of Botox. All mice that received 0.5 unit of Botox had complete hind limb paralysis documented by footprint analysis 2 days after injection but failed to tolerate anesthesia and were euthanized 24 hours after operation due to their critical condition. In contrast, the external fixator was well tolerated and effectively immobilized the limb. There was a single occurrence of intraoperative technical error in the external fixator group that led to euthanasia. No mechanical failure or complication was observed. Botox paralysis was not a viable option for postoperative restriction of motion and joint loading in mice. However, external fixation was an effective method for complete knee immobilization and can be used in murine models requiring postoperative control of knee loading. This study introduces a robust research tool to allow control of postoperative joint loading in animal models such as ACL reconstruction, permitting study of the effects of mechanical load on the biologic aspects of tendon-to-bone healing.

Abstract As our knowledge and technology advance, the indications for elbow arthroscopy continue to grow rapidly. During this expansion, a number of new portals have been described and reported using variable nomenclature and location descriptions. Accordingly, a comprehensive review of these portals is warranted. Given the concern for potential iatrogenic injury to surrounding neurovascular structures, a discussion of these critical nerves and vessels is also timely. In this work, we review pertinent surface anatomy; portal nomenclature, locations, and utility; and review distances to the nearest structures at risk. Technique Video video See video under supplementary data.

Abstract The field of elbow arthroscopy has evolved significantly since the procedure was first introduced more than 30 years ago. As our knowledge and understanding grows, numerous technical modifications have been made to improve the safety and efficacy of elbow arthroscopy. One of the most significant modifications is the change from the supine hanging position to the supine‐suspended position with the use of a mechanical arm holder. Currently, the supine‐suspended and lateral decubitus positions are the 2 most commonly used techniques. In this work, we discuss the history of the supine position, provide key points for proper patient positioning, and detail the steps of diagnostic elbow arthroscopy. It is our hope that this work will serve as an up‐to‐date review and summary of the most critical components of this procedure for emerging elbow arthroscopists. Technique Video video See video under supplementary data.

Abstract In recent years, arthroscopy has gained popularity as a preferred treatment of a multitude of pathologies affecting the elbow. Since its initial description in 1985, many modifications have been made as our knowledge and technology have advanced. Currently, the majority of arthroscopic procedures are performed in either the lateral decubitus or supine suspended position. In this work, we discuss the history, patient positioning, and key steps for performing elbow arthroscopy in the lateral decubitus position. In addition to key steps, a number of strengths and limitations of this set up are discussed in detail. When properly executed, elbow arthroscopy can be performed in a safe and efficient manner with minimal risk to patients. Technique Video video See video under supplementary data.

Abstract Treatment of femoroacetabular impingement through an arthroscopic approach has gained widespread popularity in recent years. Although outcomes are generally favorable, one of the most common reasons for failure is incomplete resection of cam lesions of the femoral neck. As a result, the T‐capsulotomy has been introduced as a method for improving access to the femoral head‐neck junction, which is not always visible through a standard interportal capsulotomy. The T‐capsulotomy has the benefits of improving arthroscopic visualization of the femoral neck, reducing overall fluoroscopy exposure for the patient and surgeon, and facilitating capsular plication. We present a reliable and efficient method for creating and repairing the T‐capsulotomy. We routinely perform this technique in patients with cam lesions that are too large or too distal to safely visualize and decompress through an interportal capsulotomy. Technique Video video See video under supplementary data.

Abstract Capsulotomy is typically performed during arthroscopic treatment for femoroacetabular impingement. As the frequency of hip arthroscopy continues to expand rapidly, increased attention is being paid to the implications of interportal capsulotomy and the need for repair. To minimize the risk of postoperative instability, capsular closure has been recommended to restore the anatomy and biomechanical function of the capsule. We present a reliable, efficient, and effective method for arthroscopic closure of the interportal capsulotomy after hip arthroscopy. Technique Video video See video under supplementary data.

Abstract Anterior shoulder instability is often accompanied by a Hill‐Sachs defect on the humeral head that can contribute to recurrent instability if not addressed at the time of surgery. We describe a method of performing arthroscopic remplissage to treat engaging Hill‐Sachs lesions in patients with glenohumeral instability. It has the benefits of being an efficient procedure that can be performed with minimal technical difficulty and can be used to augment other stabilization procedures such as labral repair. The indications for this technique include the presence of an engaging Hill‐Sachs defect in patients will little or no glenoid bone loss. In appropriately selected patients, arthroscopic remplissage has shown reduced rates of recurrent instability. Technique Video video See video under supplementary data.

Background: Patients with patellar instability and a tibial tubercle–trochlear groove (TT-TG) distance ≥20 mm may be candidates for distal tubercle realignment surgery. Although this variable has proven valuable in predicting recurrent dislocations, it is not individualized to patient size, bony structure, or patellofemoral mechanics. Purpose: To develop a patellar instability ratio (PIR) that predicts the risk of recurrent instability based on the TT-TG distance to patient-specific anatomy. Study Design: Cohort study; Level of evidence, 3. Methods: On magnetic resonance imaging scans of 59 knees with patellar instability, the TT-TG distance, tibial tubercle–posterior cruciate ligament (TT-PCL) distance, sagittal patellar length (PL), sagittal trochlear length (TL), axial patellar width (PW), and axial trochlear width (TW) were calculated by 2 observers in a blinded and randomized fashion. Patients were divided into 2 groups: those with a single dislocation and those with multiple (≥2) dislocations. The ability of the TT-TG and TT-PCL distances as well as the 8 different ratios to predict recurrent instability was assessed by calculating odds ratios (ORs), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each measure. Results: Twelve knees (20%) experienced a single dislocation, while 47 (80%) sustained multiple dislocations. A TT-TG distance ≥20 mm was predictive of recurrent instability, with a sensitivity, specificity, and PPV of 21%, 100%, and 100%, respectively. The OR for TT-TG ≥20 mm was 5.38 ( P = .29), while the highest ORs for recurrent instability were noted for a TT-TG/PW ≥0.4 (OR, 7.37; P = .02) and a TT-TG/TW ≥0.5 (OR, 8.88; P = .04). The sensitivity, specificity, and PPV of a TT-TG/PW ≥0.4 were 62%, 83%, and 94%, respectively, while those of a TT-TG/TW ≥0.5 were 45%, 92%, and 95%, respectively. Conclusion: Two novel PIRs (TT-TG/TW and TT-TG/PW) were identified and found to more effectively predict recurrent instability than the TT-TG distance alone. Each ratio takes into account patient-specific anatomy and can be measured in an accurate and reliable fashion by clinicians. These PIRs are a step toward overcoming some of the limitations of using the TT-TG distance in isolation. Further investigation into the clinical applications and utility of the TT-TG/TW is warranted.

Objectives: Patients with patellar instability and tibial tubercle to trochlear groove (TT-TG) distances ≥ 20 mm are often considered to have pathologic lateralization of the tibial tubercle (TT) relative to the femoral trochlea and may be candidates for TT realignment surgery. Although this variable has proven valuable in predicting risk of recurrent dislocations, the measure is limited in that it is not individualized to the patient and does not consider patient size, bony morphology, or patellofemoral mechanics. The purpose of this study was to develop a Patellar Instability Ratio (PIR) that predicts the risk of recurrent instability based on the TT-TG distance relative to patient specific anatomy. Methods: Fifty-nine patients with a clinical diagnosis of patellar instability were included in the study. A number of measures were calculated on MRI by two observers (one staff orthopedic surgeon and one senior resident) in a blinded and randomized fashion. Variables analyzed included: TT-TG, tibial tubercle to posterior cruciate ligament distance (TT-PCL), sagittal patellar length (PL), sagittal trochlear length (TL), axial patellar width (PW), axial trochlear width (TW), sagittal patellofemoral engagement (SPE; SPE=TL/PL) and axial patellofemoral engagement (APE; APE=PW/TW). Patients were divided into two groups: those with ≤ 1 dislocation and those with ≥ 2 dislocations. Using these groups, the ability of TT-TG, TT-PCL, and 12 different ratios with cut-off values to predict recurrent instability was assessed by calculating odds ratios (OR), C-statistics, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each of the ratios. P values < 0.05 were considered significant. Results: Mean follow up was 6.6 years. Twelve patients (20%) did not experience recurrent instability while 47 (80%) sustained two or more dislocations during the study period. Pathologic TT-TG (≥ 20 mm) was predictive of recurrent instability with an OR of 5.38 (p=0.29). The highest OR's for recurrent instability were noted for TT-TG/PW ≥ 0.40 (OR > 7.37, p=0.02) and TT-TG/TW ≥ 0.5 (OR 8.88, p=0.04)(Table 1). PW was defined as the largest medial to lateral width of the articular surface of the patella. TW is defined as the largest articular width of the trochlea that is articulating with the patella and can be conceptualized as the “jump distance” that must be overcome for the patella to dislocate. The sensitivity and specificity of TT-TG/PW ratio ≥ 0.40 was 61% and 83% and that of TT-TG/TW ≥ 0.50 was 59% and 92%, respectively. PPV for TT-TG/PW ≥ 0.40 was 94% while that of TT-TG/TW ≥ 0.49 was 97%. Conclusion: Two distinct PIR (TT-TG/PW and TT-TG/TW) have been identified that predict recurrent patellar instability more accurately than TT-TG ≥ 20 mm with PPV's ≥ 94% and OR's > 7 for both measures. These ratios take into consideration the TT-TG relative to patient specific size and anatomy. Further research is needed to determine if patients with increased PIR benefit from TT osteotomy.

Purpose The purpose of this study was to determine failure rates, functional outcomes, and risk factors for failure after revision anterior shoulder stabilization surgery in high‐risk adolescent athletes. Methods Adolescent athletes who underwent primary anterior shoulder stabilization were reviewed. Patients undergoing subsequent revision stabilization surgery were identified and analyzed. Failure rates after revision surgery were assessed by Kaplan‐Meier analysis. Failure was defined as recurrent instability requiring reoperation. Functional outcomes included the Marx activity score; American Shoulder and Elbow Surgeons score; and University of California, Los Angeles score. The characteristics of patients who required reoperation for recurrent instability after revision surgery were compared with those of patients who required only a single revision to identify potential risk factors for failure. Results Of 90 patients who underwent primary anterior stabilization surgery, 15 (17%) had failure and underwent revision surgery (mean age, 16.6 years; age range, 14 to 18 years). The mean follow‐up period was 5.5 years (range, 2 to 12 years). Of the 15 revision patients, 5 (33%) had recurrent dislocations and required repeat revision stabilization surgery at a mean of 50 months (range, 22 to 102 months) after initial revision. No risk factors for failure were identified. The Kaplan‐Meier reoperation‐free estimates were 86% (95% confidence interval, 67% to 100%) at 24 months and 78% (95% confidence interval, 56% to 100%) at 48 months after revision surgery. The mean final Marx activity score was 14.8 (range, 5 to 20); American Shoulder and Elbow Surgeons score, 82.1 (range, 33 to 100); and University of California, Los Angeles score, 30.8 (range, 16 to 35). Conclusions At 5.5 years' follow‐up, adolescent athletes had a high failure rate of revision stabilization surgery and modest functional outcomes. We were unable to convincingly identify specific risk factors for failure of revision surgery. Level of Evidence Level IV, retrospective therapeutic case series.