Superior Capsule Reconstruction Using Acellular Dermal Allograft Secured at 45° of Glenohumeral Abduction Improves the Superior Stability of the Glenohumeral Joint in Irreparable Massive Posterosuperior Rotator Cuff Tears.

PURPOSE: The purpose of the current study was to create a dynamic cadaveric shoulder model to determine the effect of graft fixation angle on shoulder biomechanics following SCR and to assess which commonly used fixation angle (30° vs 45° of abduction) results in superior glenohumeral biomechanics. METHODS: Twelve fresh-frozen cadaveric shoulders were evaluated using a dynamic shoulder testing system. Humeral head translation, subacromial and glenohumeral contact pressures were compared among 4 conditions: 1) Intact, 2) Irreparable supra- and infraspinatus tendon tear, 3) SCR using acellular dermal allograft (ADA) fixation at 30° of abduction, and 4) SCR with ADA fixation at 45° of abduction. RESULTS: SCR at both 30° (0.287 mm, CI: -0.480 - 1.05 mm; P < .0001) and 45° (0.528 mm, CI: -0.239-1.305 mm; P = .0006) significantly decreased superior translation compared to the irreparably torn state. No significant changes in subacromial peak contact pressure were observed between any states. The average glenohumeral contact pressure increased significantly following creation of an irreparable RCT (373 kPa, CI: 304-443 vs 283 kPa, CI 214-352; P = .0147). The SCR performed at 45° (295 kPa, CI: 226-365, P = .0394) of abduction significantly decreased the average glenohumeral contact pressure compared to the RCT state. There was no statistically significant difference between the average glenohumeral contact pressure of the intact state and SCR at 30° and 45°. CONCLUSION: SCR improved the superior stability of the glenohumeral joint when the graft was secured at 30° or 45° of glenohumeral abduction. Fixation at 45° of glenohumeral abduction provided more stability than did fixation at 30°. CLINICAL RELEVANCE: Grafts attached at 45° of glenohumeral abduction biomechanically restore the glenohumeral stability after SCR using ADA better than fixation at 30° of glenohumeral abduction.

Biomechanical Evaluation of Knotless and Knotted All-Suture Anchor Repair Constructs in 4 Bankart Repair Configurations.

PURPOSE: To evaluate the biomechanical performance of Bankart repair using 1.8-mm knotless all-suture anchors in comparison to 1.8-mm knotted all-suture anchors with both simple and horizontal mattress stitch configurations. METHODS: Thirty fresh-frozen human cadaveric shoulders were dissected to the capsule, leaving the glenoid and humeral capsular insertions intact. A standardized anteroinferior labral tear was created and repaired using 3 anchors. A 2 × 2 factorial design was implemented, with 6 matched pairs randomized between knotless and knotted anchor repairs and 6 matched pairs randomized into simple and horizontal mattress stitch configurations. In addition, 6 unpaired shoulders were used to evaluate the native capsulolabral state. First failure load, ultimate load, and stiffness were assessed. Linear mixed-effects modeling was used to compare endpoints. Digital image correlation was used to evaluate capsular strain throughout testing. Failure modes were reported qualitatively. RESULTS: The knotless all-suture anchor repair showed similar biomechanical strength to the knotted all-suture anchors for first failure load (coefficient, 142 N; 95% confidence interval [CI], -30 to 314 N; P = .12), ultimate load (coefficient, 11.1 N; 95% CI, -104.9 to 127.2 N; P = .847), and stiffness (coefficient, 3.4 N/mm2; 95% CI, -14.1 to 20.9 N/mm2; P = .697) when stitch configuration was held constant. No statistically significant differences were found on comparison of simple and mattress stitch configurations for first failure load (coefficient, -31 N; 95% CI, -205 to 143 N; P = .720), ultimate load (coefficient, 112 N; 95% CI, -321 to 97 N; P = .291), and stiffness (coefficient, -9.6 N/mm2; 95% CI, -27.3 to 8.1 N/mm2; P = .284) when anchor type was held constant. Specimens with knotless anchors and simple stitch techniques resulted in lower stiffness compared with the native state (P = .030). The knotless-mattress configuration resulted in significantly lower strain than the knotted-mattress (P = .037) and knotless-simple (P = .019) configurations and was the only configuration that did not result in a significant increase in strain compared with the intact specimens (P = .216). Fewer instances of suture slippage (loss of loop security) were observed with knotless anchors versus knotted anchors (11% vs 30%), and less soft-tissue failure was observed with the mattress stitch configuration versus the simple stitch configuration (36% vs 47%). CONCLUSIONS: Knotless and knotted all-suture anchor repairs with simple and mattress stitch configurations showed similar values of ultimate load, first failure load, and stiffness. However, the horizontal mattress stitch configuration proved to decrease capsular strain more similarly to the native state compared with the simple stitch configuration. Ultimate load and first failure load for all repairs were similar to those of the native state. CLINICAL RELEVANCE: Knotless all-suture anchors have a smaller diameter than solid anchors, can be inserted through curved guides, and preserve glenoid bone stock. This study presents knotless, tensionable all-suture anchor repair for labral tears that displays high biomechanical fixation strength, similar to the native capsulolabral state.

Pediatric Anterior Cruciate Ligament Reruptures Are Related to Lower Functional Scores at the Time of Return to Activity: A Prospective, Midterm Follow-up Study.

BACKGROUND: Skeletally immature patients show a higher rate of anterior cruciate ligament (ACL) reruptures. A better understanding of the risk factors for an ACL rerupture in this population is critical. PURPOSE/HYPOTHESIS: The objective of this study was to analyze preoperative, intraoperative, and postoperative characteristics of pediatric patients undergoing ACL reconstruction and determine the relationship of these factors with an ACL rerupture. It was hypothesized that patients with worse activity scores and knee function at the time of return to activity would have a higher rate of ACL reruptures at midterm follow-up. Additionally, it was hypothesized that most ACL reruptures would occur before age 20 years in the study population. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 65 skeletally immature patients (age <16 years) with ACL ruptures underwent reconstruction with a quadruple hamstring tendon graft between 2002 and 2016. Of these patients, 52 were available for the study. Patient characteristics, surgical details, Tegner and Lysholm scores, and ACL reconstruction outcomes were recorded. Patients were analyzed and compared according to ACL rerupture occurrence. RESULTS: Of the 52 patients, 18 (34.6%) experienced an ACL rerupture after reconstruction. The majority of reruptures (77.8%) occurred before age 20 years. There were 2 patients who sustained ACL reruptures during the rehabilitation period before they returned to activity. The majority of reruptures occurred after 12 months (83.2%), with 66.6% occurring after 24 months. Upon returning to activity between 6 and 9 months postoperatively, patients who ended up with intact ACL grafts reported 69% higher mean Tegner scores (P = .006) and 64% higher mean Lysholm scores than patients who sustained ACL reruptures (P < .001). Within the limits of this study, we could identify no statistical relationship between the rate of ACL reruptures and different sport types, surgical techniques, or associated injuries (P > .05). CONCLUSION: Skeletally immature patients who underwent ACL reconstruction and sustained ACL reruptures had lower Tegner and Lysholm scores upon returning to activity than patients without ACL reruptures. In addition, most ACL reruptures occurred in patients younger than 20 years (77.8%) and after 24 months postoperatively (66.6%).

Treatment and outcomes of lateral collateral ligament injury associated with anterior and posterior cruciate ligament injury at 2-year follow-up.

BACKGROUND: Injuries to the lateral collateral ligament (LCL) are most commonly associated with anterior cruciate ligament (ACL) injury than with posterior cruciate ligament (PCL) injury. There is currently a paucity in the literature in regards to treatment and outcomes of such lesions. METHODS: 30 patients underwent surgical treatment of concomitant LCL and ACL injury or concomitant LCL and PCL injury with follow-up postoperative period of two years. The Lysholm score and varus stress radiographs was calculated and analysed before and at 6, 12, and 24 months postoperatively. RESULTS: There was a significant increase in scores between two timepoints over the follow-up period for both groups: before surgery and after 6 months, and between 6 and 12 months (p < 0.05). The lateral joint opening measured on the varus stress radiographs was greater in group 2 than in group 1 before surgery (p = 0.04). When assessing each group separately, the lateral joint opening decreased at each timepoint in the first year for both groups (p < 0.05). CONCLUSION: Patients diagnosed with combined LCL and PCL injuries were shown to have a higher degree of lateral opening at the time of injury when compared to patients with combined LCL and ACL injuries. However, there was no difference in lateral joint opening on stress radiography after 12 months postoperatively in either group. Finally Lysholm scores for both groups significantly increased between the preoperative period and 6 months postoperatively, as well as between 6 months and 12 months postoperatively. LEVEL OF EVIDENCE: III.

Different Suture Materials for Arthroscopic Transtibial Pull-out Repair of Medial Meniscal Posterior Root Tears: A Human Biomechanical Study.

BACKGROUND: Transtibial pull-out repair of the medial meniscal posterior root (MMPR) has been largely assessed through biomechanical studies. Biomechanically comparing different suture types would further optimize MMPR fixation and affect clinical care. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the optimal suture material for MMPR fixation. It was hypothesized that ultra high-molecular weight polyethylene (UHMWPE) suture tape would be biomechanically superior to UHMWPE suture and standard suture. STUDY DESIGN: Controlled laboratory study. METHODS: The MMPR attachment was divided in 24 human cadaveric knees and randomly assigned to 3 repair groups: UHMWPE suture tape, UHMWPE suture, and standard suture. Specimens were dissected down to the medial meniscus, and the posterior root attachments were sectioned off the tibia. Two-tunnel transtibial pull-out repair with 2 sutures, as determined by the testing group, was performed. The repair constructs were cyclically loaded between 10 and 30 N at 0.5 Hz for 1000 cycles to mimic the forces experienced on the medial meniscus during postoperative rehabilitation. Displacement was recorded at 1, 50, 100, 500, and 1000 cycles. Ultimate failure load, displacement at failure, and load at 3 mm of displacement (clinical failure) were also recorded. RESULTS: UHMWPE suture tape had significantly less displacement of the medial meniscus when compared with standard suture at 1 (-0.22 mm [95% CI, -0.41 to -0.02]; P = .025) and 50 (-0.35 mm [95% CI, -0.67 to -0.03]; P = .029) cycles. There were no other significant differences observed in displacement between groups at any number of cycles. UHMWPE suture tape had significantly less displacement at the time of failure than standard suture (-3.71 mm [95% CI, -7.17 to -0.24]; P = .034). UHMWPE suture tape had a significantly higher load to reach the clinical failure displacement of 3 mm than UHMWPE suture (15.64 N [95% CI, 0.02 to 31.26]; P = .05). There were no significant differences in ultimate failure load between groups. CONCLUSION: The meniscal root repair construct with UHMWPE suture tape may be stronger and less prone to displacement than that with standard suture or UHMWPE suture. CLINICAL RELEVANCE: UHMWPE suture tape may provide better clinical results compared with UHMWPE suture and standard suture.

Utilization of Transtibial Centralization Suture Best Minimizes Extrusion and Restores Tibiofemoral Contact Mechanics for Anatomic Medial Meniscal Root Repairs in a Cadaveric Model.

BACKGROUND: Although posterior medial meniscal root (PMMR) repairs are often successful, postoperative meniscal extrusion after a root repair has been identified as a potential clinical problem. PURPOSE/HYPOTHESIS: The purpose was to quantitatively evaluate the tibiofemoral contact mechanics and extent of meniscal extrusion after a PMMR repair. It was hypothesized that the addition of a centralization suture (into the posterior medial tibial plateau) would help restore normal joint load-bearing characteristics and restore the native amount of meniscal extrusion after a root tear. Furthermore, we hypothesized that the amount of meniscal extrusion would be greatest in loaded and flexed knees when measured at the posterior border of the medial collateral ligament (MCL). STUDY DESIGN: Controlled laboratory study. METHODS: Meniscal extrusion and tibiofemoral contact mechanics were measured using 3-dimensional digitization and pressure sensors in 10 nonpaired, human cadaveric knees. The PMMR of each knee was tested under 6 states: (1) intact; (2) type 2A PMMR tear; (3) anatomic transtibial pull-out root repair; (4) anatomic transtibial pull-out repair with centralization; (5) nonanatomic transtibial pull-out repair; and (6) nonanatomic transtibial pull-out repair with centralization, with randomization of the order of conditions 3 and 4, and 5 and 6. The testing protocol loaded knees with a 1000-N axial compressive force at 4 flexion angles (0°, 30°, 60°, 90°) in each state. Meniscal extrusion was measured with a 3-dimensional coordinate digitizer at 0° and 90° in both the loaded and unloaded states and calculated from the difference from the articular margin of the tibia to the periphery of the meniscus. Peak contact pressure, contact area, and total contact pressure were also recorded for all states at all flexion angles. Statistical analysis investigated the independent effects of flexion, state, and loading using 3 distinct 2-factor models. RESULTS: Differences in the contact mechanics between repair techniques were most notable at higher flexion angles, demonstrating significantly higher average and peak contact pressures for nonanatomic repair states when compared with anatomic repairs with and without centralization (all P < .05). In unloaded knees at full extension, the magnitude of medial meniscal extrusion was significantly higher at the posterior border of the MCL compared with the posterior medial tibia ( P < .001) and adjacent to the root attachment on the tibia locations ( P < .001). Both anatomic repair states had no significant difference in the degree of extrusion when compared with the intact state. CONCLUSION: The anatomic transtibial pull-out root repair and the anatomic transtibial pull-out root repair with centralization techniques best restored contact mechanics of the knee and meniscal extrusion when compared with root tear and nonanatomic repair states at time zero. There were no significant differences in contact pressure or magnitude of extrusion between the anatomic repair state and the anatomic repair with centralization state. We found that extrusion is best measured in the coronal plane at the posterior border of the MCL for unloaded knees. However, the degree of extrusion increased as the knee was loaded and flexed to 90°. CLINICAL RELEVANCE: When there are concerns about meniscal extrusion with a medial meniscal root repair, the addition of a centralization suture may be beneficial for patients in reducing pathologic meniscal extrusion and restoring joint contact mechanics.

Defining the three most responsive and specific CT measurements of ankle syndesmotic malreduction.

PURPOSE: The purpose of this study was to compare the reliability and accuracy of existing computed tomography (CT) methods for measuring the distal tibiofibular syndesmosis in uninjured, paired cadaveric specimens and in simulated malreduction models. It was hypothesized that a repeatable set of measurements exists to accurately and quantitatively describe the typical forms of syndesmotic malreduction using contralateral ankle comparison. METHODS: Twelve cadaveric lower-leg specimen pairs were imaged with CT to generate models for this study. Thirty-five measurements were performed on each native model. Next, four distinct fibular malreductions were produced via digital simulation and all measurements were repeated for each state: (1) 2-mm lateral translation; (2) 2-mm posterior translation; (3) 7-degree external rotation; (4) the previous three states combined. The modified standardized response mean (mSRM) was calculated for each measurement. To assess rater reliability and side-to-side agreements of the native state measurements, intraclass correlation coefficients (ICC) and Pearson correlation coefficients (PCC) were calculated, respectively. RESULTS: The most responsive measurements for detecting isolated malreduction were the Leporjärvi clear space for lateral translation, the Nault anterior tibiofibular distance for posterior translation, and the Nault talar dome angle for external rotation of the fibula. These measurements demonstrated fair to excellent inter-rater ICCs (0.64-0.76) and variable side-to-side PCCs (0.14-0.47). CONCLUSIONS: The most reliable method to assess the syndesmosis on CT was to compare side-to-side differences using three distinct measurements, one for each type of fibular malreduction, allowing assessment of the magnitude and directionality of syndesmosis malreduction. Reliable evaluation is essential for assessing subtle syndesmosis injuries, malreduction and surgical planning.

Biomechanical Comparison of Vertical Mattress and Cross-stitch Suture Techniques and Single- and Double-Row Configurations for the Treatment of Bucket-Handle Medial Meniscal Tears.

BACKGROUND: Given the variety of suturing techniques for bucket-handle meniscal repair, it is important to assess which suturing technique best restores native biomechanics. PURPOSE/HYPOTHESIS: To biomechanically compare vertical mattress and cross-stitch suture techniques, in single- and double-row configurations, in their ability to restore native knee kinematics in a bucket-handle medial meniscal tear model. The hypothesis was that there would be no difference between the vertical mattress and cross-stitch double-row suture techniques but that the double-row technique would provide significantly improved biomechanical parameters versus the single-row technique. STUDY DESIGN: Controlled laboratory study. METHODS: Ten matched pairs of human cadaver knees were randomly assigned to the vertical mattress (n = 10) or cross-stitch (n = 10) repair group. Each knee underwent 4 consecutive testing conditions: (1) intact, (2) displaced bucket-handle tear, (3) single-row suture configuration on the femoral meniscus surface, and (4) double-row suture configuration (repair of femoral and tibial meniscus surfaces). Knees were loaded with a 1000-N axial compressive force at 0°, 30°, 60°, 90°, and 120° of flexion for each condition. Resultant medial compartment contact area, average contact pressure, and peak contact pressure data were recorded. RESULTS: Intact state contact area was not restored at 0° ( P = .027) for the vertical double-row configuration and at 0° ( P = .032), 60° ( P < .001), and 90° ( P = .007) of flexion for the cross-stitch double-row configuration. No significant differences were found in the average contact pressure and peak contact pressure between the intact state and the vertical mattress and cross-stitch repairs with single- and double-row configurations at any flexion angles. When the vertical and cross-stich repairs were compared across all flexion angles, no significant differences were observed in single-row configurations, but in double-row configurations, cross-stitch repair resulted in a significantly decreased contact area, average contact pressure, and peak contact pressure (all P < .001). CONCLUSION: Single- and double-row configurations of the vertical mattress and cross-stitch inside-out meniscal repair techniques restored native tibiofemoral pressure after a medial meniscal bucket-handle tear at all assessed knee flexion angles. Despite decreased contact area with a double-row configuration, mainly related to the cross-stitch repair, in comparison with the intact state, the cross-stitch double-row repair led to decreased pressure as compared with the vertical double-row repair. These findings are applicable only at the time of the surgery, as the biological effects of healing were not considered. CLINICAL RELEVANCE: Medial meniscal bucket-handle tears may be repaired with the single- or double-row configuration of vertical mattress or cross-stitch sutures.

Mini-open Repair of the Floating Anterior Inferior Glenohumeral Ligament: Combined Treatment of Bankart and Humeral Avulsion of the Glenohumeral Ligament Lesions.

Anterior shoulder instability often results from avulsion of the anterior inferior glenohumeral ligament (aIGHL) off its insertion on the glenoid, yielding a Bankart lesion. Although less common, avulsion of the ligament attachment to the humerus results in a humeral avulsion of the glenohumeral ligament (HAGL) lesion. Combined Bankart and HAGL lesions, also termed the "floating aIGHL," create a complex pathology that is not detailed significantly in the literature. We believe a mini-open approach is a viable and reproducible procedure for treatment because it allows for protection of the axillary nerve and other neurovascular structures while providing optimal exposure to both the humeral insertion site of the distal aIGHL and the Bankart lesion, ensuring anatomic restoration. The purpose of this Technical Note is to describe our preferred technique to surgically treat the floating aIGHL, consisting of an anterior HAGL and concomitant Bankart lesion repair through a mini-open approach.

Effects of Capsular Reconstruction With an Iliotibial Band Allograft on Distractive Stability of the Hip Joint: A Biomechanical Study.

BACKGROUND: The capsular ligaments and the labral suction seal cooperatively manage distractive stability of the hip. Capsular reconstruction using an iliotibial band (ITB) allograft aims to address capsular insufficiency and iatrogenic instability. However, the extent to which this procedure may restore hip distractive stability after a capsular defect is unknown. PURPOSE: To evaluate the biomechanical effects of capsular reconstruction on distractive stability of the hip joint. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric hip specimens were dissected to the level of the capsule and axially distracted in 3 testing states: intact capsule, partial capsular defect, and capsular reconstruction with an ITB allograft. Each femur was compressed with 500 N of force and then distracted 6 mm relative to the neutral position at 0.5 mm/s. Distractive force was continuously recorded, and the first peak delineating 2 phases of hip distractive stability in the force-displacement curve was analyzed. RESULTS: The median force at maximum distraction in the capsular reconstruction state (156 N) was significantly greater than that in the capsular defect state (89 N; P = .036) but not significantly different from that in the intact state (218 N; P = .054). Median values for distractive force at first peak (60 N, 72 N, and 61 N, respectively; P = .607), distraction at first peak (2.3 mm, 2.3 mm, and 2.5 mm, respectively; P = .846), and percentage decrease in distractive force (35%, 78%, and 63%, respectively; P = .072) after the first peak were not significantly different between the intact, defect, and reconstruction states. CONCLUSION: Capsular reconstruction with an ITB allograft significantly increased the force required to distract the hip compared with a capsular defect in a cadaveric model. To our knowledge, this is the first study to report an initial peak distractive force and to propose 2 distinct phases of hip distractive stability. CLINICAL RELEVANCE: The consequences of a capsular defect on distractive stability of the hip may be underappreciated among the orthopaedic community; with that said, capsular reconstruction using an ITB allograft provided significantly increased distractive stability and should be considered an effective treatment option for patients with symptomatic capsular deficiency.