Anatomic Acromioclavicular Joint Reconstruction with and without Acromioclavicular Ligament Reconstruction: A Comparative Biomechanical Study.

Background: The purpose of this study was to determine if adding a reconstructed superior acromioclavicular (AC) joint ligament adds significant biomechanical stability to the AC joint over anatomic coracoclavicular (CC) ligament reconstruction alone. Methods: Fourteen cadaver shoulders were used for the comparison of biomechanical stability among the anatomic CC ligament reconstruction alone, CC and AC ligament reconstruction, and the intact groups by measuring the displacement under cyclic loads. A load to failure test was then performed in the vertical direction at a loading rate of 2 mm /sec to determine surgical-repair joints' tolerance to the maximum failure load. Results: The average peak-to-peak displacement induced by cyclic load in the sagittal axis and vertical axis direction was not significantly different between CC ligament reconstruction, CC and AC ligament reconstruction, and intact groups. The maximum failure load for the CC reconstruction (224.9 ± 91.8 N (Mean ± SEM)) was lower than CC/AC reconstruction groups (326.2 ± 123.3 N). The CC/AC reconstruction group failed at a significantly higher load (t test, p = 0.016) than the CC reconstruction group. Conclusion: CC/AC reconstruction surgical technique yielded a better shoulder stability than CC ligament alone reconstruction that may better maintain reduction of the AC joint.Level of Evidence: Level II.

Quadriceps tendon autograft is becoming increasingly popular in revision ACL reconstruction.

PURPOSE: To evaluate trends in revision anterior cruciate ligament reconstruction (ACL-R), with emphasis on intra-articular findings, grafts, and concurrent procedures. It was hypothesized that revision ACL-Rs over time show a trend toward increased complexity with increased use of autografts over allografts. METHODS: This was a two-center retrospective study including patients undergoing revision ACL-R between 2010 and 2020. Demographic and surgical data including intra-articular findings and concurrent procedures were collected and compared for the time periods 2010-2014 and 2015-2020. All collected variables were compared between three pre-defined age groups (< 20 years, 20-30 years, > 30 years), right and left knees, and males and females. A time series analysis was performed to assess trends in revision ACL-R. RESULTS: This study included 260 patients with a mean age of 26.2 ± 9.4 years at the time of the most recent revision ACL-R, representing the first, second, third, and fourth revision ACL-R for 214 (82%), 35 (14%), 10 (4%), and 1 (< 1%) patients, respectively. Patients age > 30 years showed a significantly longer mean time from primary ACL-R to most recent revision ACL-R (11.1 years), compared to patients age < 20 years (2.2 years, p < 0.001) and age 20-30 years (5.5 years, p < 0.05). Quadriceps tendon autograft was used significantly more often in 2015-2020 compared to 2010-2014 (49% vs. 18%, p < 0.001). A high rate of concurrently performed procedures including meniscal repairs (45%), lateral extra-articular tenodesis (LET; 31%), osteotomies (13%), and meniscal allograft transplantations (11%) was shown. Concurrent LET was associated with intact cartilage and severely abnormal preoperative knee laxity and showed a statistically significant and linear increase over time (p < 0.05). Intact cartilage (41%, p < 0.05), concurrent medial meniscal repairs (39%, p < 0.05), and LET (35%, non-significant) were most frequently observed in patients aged < 20 years. CONCLUSION: Quadriceps tendon autograft and concurrent LET are becoming increasingly popular in revision ACL-R. Intact cartilage and severely abnormal preoperative knee laxity represent indications for LET in revision ACL-R. The high rate of concurrent procedures observed demonstrates the high surgical demands of revision ACL-R. LEVEL OF EVIDENCE: Level III.

Pediatric Acetabular Osteomyelitis Treated With Hip Arthroscopy.

Osteomyelitis of the acetabulum is a rare condition accounting for only 12% of pelvic osteomyelitis cases. This report describes a previously healthy 10-year-old girl with subacute acetabular osteomyelitis and subsequent development of secondary septic arthritis of the hip. The patient presented with 3 weeks of groin pain, elevated erythrocyte sedimentation rate and C-reactive protein, synovial thickening of the hip on ultrasonography and diffuse signal uptake in the acetabulum on magnetic resonance imaging. Despite antibiotic therapy, her symptoms worsened clinically, and repeat Magnetic resonance imaging images showed worsening of the osteomyelitis with likely extension through the acetabulum and into the joint. A hip aspirate was positive for Fusobacterium, an atypical anaerobe. Hip arthroscopy, with identification of the site of extrusion and then extensive débridement and irrigation, was successful in helping to control and ultimately eradicate the infection. The patient regained normal hip function and returned to full activities. This case demonstrates how hip arthroscopy can serve as an important surgical treatment modality for acetabular osteomyelitis with intraarticular extension in addition to septic arthritis of the hip.

Glenoid exposure in shoulder arthroplasty: the role of soft tissue releases.

BACKGROUND: The deltopectoral approach is commonly used in shoulder arthroplasty. Various soft tissue releases can be performed to obtain adequate glenoid exposure, but their effectiveness is not known. The purpose of this study was to (1) quantify the effects of various releases on the amount of glenoid surface area exposure and (2) determine if common soft tissue releases performed about the shoulder significantly improve exposure of the glenoid. METHODS: A standard deltopectoral approach was used on cadaveric shoulders (n=8) in the beach chair position. The releases performed were as follows: long head of biceps, pectoralis major tendon, inferior capsule, and posterior capsule. Following each release, a custom-designed jig was used to mark the exposed glenoid surface. The glenoid was then digitized using a 3D surface scanner to quantify the exposed surface area with each release. RESULTS: The mean glenoid surface area exposure prior to any releases was 57% (SD 8%). Following release of the long head of biceps, exposure increased to 69% (SD 10%). The exposed area was increased to 83% (SD 6%) with release of the pectoralis major, and 93% (SD 2%) with inferior capsule. The entire glenoid was exposed following posterior capsule release. CONCLUSIONS: Release of the long head of biceps, pectoralis major, and inferior and posterior capsule all independently led to significant increases in glenoid surface exposure in the deltopectoral approach. Mean surface area exposed with all 3 releases was 93%. Although posterior capsular release improved exposure, the results of this study suggest that this is rarely necessary.

The all-inside all-suture technique demonstrated better biomechanical behaviors in meniscus radial tear repair.

PURPOSE: The purpose of this study was to evaluate the effectiveness of three constructs and techniques for repair of radial tears of the meniscus. METHODS: Thirty fresh frozen porcine menisci were divided equally into three groups consisting of (1) inside-out repair group, (2) a commonly used all-inside suture with anchor hybrid repair construct (AISAH) (Meniscal Cinch™), and (3) an all-inside all-suture repair construct (AIAS) (Knee Scorpion™). Radial tears were created and repaired and then the menisci were secured to the materials testing machine. Both cyclic loading and load-to-failure testing were performed. The displacement, stiffness, response to cyclic loading, and mode of failure were recorded and analyzed statistically. RESULTS: The displacement after cyclic loading (DACL) of the Cinch repair construct group was significantly higher than that of the inside-out repair construct group (p = 0.000) and AIAS repair construct (p = 0.000). There was not a statistical difference of DACL between inside-out and AIAS groups (n.s.). The inside-out construct failed at a significantly higher load than the AISAH repair construct (p = 0.000) and AIAS construct (p = 0.006). The AIAS construct failed at a significantly higher load than the AISAH repair construct (p = 0.009). The AIAS had a higher stiffness than AISAH (p = 0.047). The AIAS had a higher load at 3 mm protrusion than AISAH (p = 0.034). CONCLUSION: The AIAS repair construct had better biomechanical behaviors than AISAH construct and inside-out repair technique. Inside-out sutures and AIAS repair construct had similar biomechanical responses to cyclic loading. The AIAS can be used for meniscus tear surgical repair with less damage to peri-meniscus tissues.

Should the Pareto Principle Be Applied as a Cost Savings Method in Hip and Knee Arthroplasty?

BACKGROUND: Understanding the most significant contributions to the cost of completing total hip arthroplasty (THA) and total knee arthroplasty (TKA) is essential to optimize costs and meet funding standards. The objectives of this study are to determine whether cost distribution of THA and TKA follows the Pareto Principle (80/20 rule) and factors predictive of costs that could be modified. METHODS: All inpatient, primary, elective, and unilateral THA and TKA patients from April 2008 to September 2017 were retrospectively reviewed. The Pareto Principle was tested by dividing patients into top 5% cost increments and calculating patient cost category ratio. Relationship between patient-related factors and acute care costs and relationship between cost categories and length of stay (LOS) were examined using multiple regression. RESULTS: The Pareto Principle does not apply for THA or TKA patients, with the top 20% of costly patients accounting for approximately 30% of total costs. LOS is the strongest independent driver of costs. Operating room services and supplies accounted for over 50% of total costs but with low variability (coefficient of variation < 0.25). Laboratory and allied health costs had high variability (coefficient of variation > 1.5), but their contribution to total costs was low (from 0.76% to 5.68%). CONCLUSION: THA and TKA costs do not follow Pareto Principle, concluding that targeting top costly patients is not as effective as focusing on overall patient population. Efforts to decrease overall costs should focus on decreasing the LOS and improving operating room process efficiencies including human resources for supplies and instruments.

External sensors for detecting the activation and deactivation times of the major muscles used in walking.

Functional electrical stimulation (FES) can improve walking in individuals with mobility impairments. We evaluated accelerometers, force sensitive resistors, segment angles, and segment angular velocities to identify which sensor best determines the activation and deactivation times of the main muscles used during walking. This sensor(s) can be used in the future in conjunction with FES systems to improve walking. Able-bodied subjects walked at various speeds. Threshold levels were set for each sensor that minimized the difference between the times of activating and deactivating the electromyogram (EMG) of six muscles and the times of sensor threshold crossings as a percent of the step cycle. Mobility-impaired subjects walked at their preferred speed with and without FES to correct foot drop. Thresholds were set for these subjects so that sensor signals would cross at times that matched those of able-bodied subjects. Segment angles were generally the most effective sensor signals. Using segment angles of the thigh, shank, and foot, activation and deactivation times of the six muscles could be determined to within 6% of the step cycle. The shank segment angle produced the lowest overall error and was among the top three sensors for 10 of the 12 events (activation and deactivation of six muscle groups). A segment angle sensor was implemented using a complementary filter (accelerometer/gyroscope combination). Using this sensor improved rule-based timing of FES in subjects with foot drop as compared to accelerometers alone.