Abbreviated quantitative UTE imaging in anterior cruciate ligament reconstruction.

BACKGROUND: Existing ultrashort echo time magnetic resonance imaging (UTE MRI) methods require prohibitively long acquisition times (~ 20-40 min) to quantitatively assess the clinically relevant fast decay T2* component in ligaments and tendons. The purpose of this study was to evaluate the feasibility and clinical translatability of a novel abbreviated quantitative UTE MRI paradigm for monitoring graft remodeling after anterior cruciate ligament (ACL) reconstruction. METHODS: Eight patients who had Graftlink™ hamstring autograft reconstruction were recruited for this prospective study. A 3D double-echo UTE sequence at 3.0 Tesla was performed at 3- and 6-months post-surgery. An abbreviated UTE MRI paradigm was established based on numerical simulations and in vivo validation from healthy knees. This proposed approach was used to assess the T2* for fast decay component ([Formula: see text]) and bound water signal fraction (fbw) of ACL graft in regions of interest drawn by a radiologist. RESULTS: Compared to the conventional bi-exponential model, the abbreviated UTE MRI paradigm achieved low relative estimation bias for [Formula: see text] and fbw over a range of clinically relevant values for ACL grafts. A decrease in [Formula: see text] of the intra-articular graft was observed in 7 of the 8 ACL reconstruction patients from 3- to 6-months (- 0.11 ± 0.16 ms, P = 0.10). Increases in [Formula: see text] and fbw from 3- to 6-months were observed in the tibial intra-bone graft ([Formula: see text]: 0.19 ± 0.18 ms, P < 0.05; Δfbw: 4% ± 4%, P < 0.05). Lower [Formula: see text] (- 0.09 ± 0.11 ms, P < 0.05) was observed at 3-months when comparing the intra-bone graft to the graft/bone interface in the femoral tunnel. The same comparisons at the 6-months also yielded relatively lower [Formula: see text] (- 0.09 ± 0.12 ms, P < 0.05). CONCLUSION: The proposed abbreviated 3D UTE MRI paradigm is capable of assessing the ACL graft remodeling process in a clinically translatable acquisition time. Longitudinal changes in [Formula: see text] and fbw of the ACL graft were observed.

A Biomechanical Comparison of Alternative Graft Preparations for All-Inside Anterior Cruciate Ligament Reconstruction.

PURPOSE: To biomechanically compare alternative graft constructs for all-inside anterior cruciate ligament (ACL) reconstruction in the event that the semitendinosus harvested is too narrow or too short to make a graft larger than 8 mm. METHODS: Bovine extensor tendons were used to make 6 different 9-mm-diameter grafts: traditional 4-strand, anastomosis 4-strand, 6-strand, 3-strand, button-fixation 4-strand, and loop-and-tack 4-strand grafts. The grafts were then subjected to cyclic biomechanical testing followed by failure loading. Force at 3 and 5 mm of displacement and ultimate force were recorded for all grafts. RESULTS: Compared with the traditional 4-strand graft, the only graft that showed significant biomechanical differences during the cyclic phase of testing was the button-fixation 4-strand graft, which was characterized by lower force at 3 mm of displacement (74 ± 34 N vs 122 ± 13 N, P = .004) and 5 mm of displacement (122 ± 35 N vs 172 ± 3 N, P = .006). During failure loading, ultimate force was significantly lower for both the 6-strand graft (491 ± 186 N, P = .041) and button-fixation 4-strand graft (326 ± 27 N, P < .001) than for the traditional 4-strand graft (778 ± 176 N). All other grafts were equivalent for the parameters tested. CONCLUSIONS: The anastomosis 4-strand, 3-strand, and loop-and-tack 4-strand grafts do not biomechanically differ in cyclic loading and ultimate force from traditional 4-strand grafts. This study supports the use of anastomosis 4-strand, 3-strand, or loop-and-tack 4-strand grafts in the event that a traditional all-inside 4-strand graft cannot be prepared from a harvested semitendinosus tendon in ACL reconstruction. CLINICAL RELEVANCE: This study tests and describes alternatives to the traditional 4-strand semitendinosus autograft for all-inside ACL reconstruction in the event that the harvested tendon is not adequate.

Clinical Evaluation of an Arthroscopic Knotless Suprapectoral Biceps Tenodesis Technique: Loop 'n' Tack Tenodesis.

BACKGROUND: Pathology of the long head of the biceps tendon is a well-known cause of shoulder pain that is commonly managed with arthroscopic suprapectoral biceps tenodesis when conservative treatment fails. PURPOSE: To present an arthroscopic knotless suprapectoral biceps tenodesis technique known as "Loop 'n' Tack" tenodesis and to report the clinical outcomes of patients with a minimum 2 years of follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review of all patients who had undergone Loop 'n' Tack tenodesis between January 2009 and May 2014 was completed. Charts were reviewed, and patients were contacted for demographic data, time from surgery, concomitant procedures, and workers' compensation status, as well as visual analog scale for pain, American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation, and University of California, Los Angeles (UCLA) scores. RESULTS: Complete follow-up evaluations were performed for 59 of 68 patients (87%). Mean follow-up was 43 months. A majority (88%) of patients had at least 1 additional procedure performed at the time of biceps tenodesis. The mean ASES shoulder score improved from 42.6 preoperatively to 91.0 postoperatively (P < .001), and 54 of 59 patients (91.5%) had a good/excellent outcome, with a UCLA shoulder score >27 and ASES shoulder score >70. Three patients (5%) reported biceps cramping pain with overuse, and 2 (3.3%) reported intermittent anterior shoulder pain. No patients had developed a "Popeye" deformity at final clinical examination, and 97% reported that they were overall satisfied with the procedure. CONCLUSION: The Loop 'n' Tack tenodesis technique results in a high rate of patient satisfaction, significant improvement in shoulder outcome scores, and a low incidence of postoperative pain, with no reoperations for biceps-related pathology.

Knotless Tape Suture Fixation of Quadriceps Tendon Rupture: A Novel Technique.

Quadriceps tendon ruptures disrupt the extensor mechanism of the knee and require urgent surgical management. Traditional repair techniques have had mixed biomechanical and clinical results risking weakness and extensor lag. We describe a novel technique using tape suture and knotless anchors, which has performed superiorly during biomechanical testing and yielded terrific early clinical results.

Patellar Tendon Repair Augmentation With a Knotless Suture Anchor Internal Brace: A Biomechanical Cadaveric Study.

BACKGROUND: Patellar tendon repair with braided polyethylene suture alone is subject to knot slippage and failure. Several techniques to augment the primary repair have been described. Purpose/Hypothesis: The purpose was to evaluate a novel patellar tendon repair technique augmented with a knotless suture anchor internal brace with suture tape (SAIB). The hypothesis was that this technique would be biomechanically superior to a nonaugmented repair and equivalent to a standard augmentation with an 18-gauge steel wire. STUDY DESIGN: Controlled laboratory study. METHODS: Midsubstance patellar tendon tears were created in 32 human cadaveric knees. Two comparison groups were created. Group 1 compared #2 supersuture repair without augmentation to #2 supersuture repair with SAIB augmentation. Group 2 compared #2 supersuture repair with an 18-gauge stainless steel cerclage wire augmentation to #2 supersuture repair with SAIB augmentation. The specimens were potted and biomechanically loaded on a materials testing machine. Yield load, maximum load, mode of failure, plastic displacement, elastic displacement, and total displacement were calculated for each sample. Standard statistical analysis was performed. RESULTS: There was a statistically significant increase in the mean ± SD yield load and maximum load in the SAIB augmentation group compared with supersuture alone (mean yield load: 646 ± 202 N vs 229 ± 60 N; mean maximum load: 868 ± 162 N vs 365 ± 54 N; P < .001). Group 2 showed no statistically significant differences between the augmented repairs (mean yield load: 495 ± 213 N vs 566 ± 172 N; P = .476; mean maximum load: 737 ± 210 N vs 697 ± 130 N; P = .721). CONCLUSION: Patellar tendon repair augmented with SAIB is biomechanically superior to repair without augmentation and is equivalent to repair with augmentation with an 18-gauge stainless steel cerclage wire. CLINICAL RELEVANCE: This novel patellar tendon repair augmentation is equivalent to standard 18-gauge wire augmentation at time zero. It does not require a second surgery for removal, and it is biomechanically superior to primary repair alone.

Knotless Suture Anchor With Suture Tape Quadriceps Tendon Repair Is Biomechanically Superior to Transosseous and Traditional Suture Anchor-Based Repairs in a Cadaveric Model.

PURPOSE: To compare the biomechanical properties of a knotless suture anchor with suture tape quadriceps tendon repair technique with transosseous and suture anchor repair techniques. METHODS: Twenty matched pairs of cadaveric knees underwent a quadriceps tendon avulsion followed by repair via the use of transosseous tunnels with #2 high-strength sutures, 5.5-mm biocomposite fully threaded suture anchors with #2 high-strength sutures, or 4.75-mm biocomposite knotless suture anchors with suture tape. Ten knees were repaired via transosseous repair and 10 via fully threaded suture anchor repair, and their matched specimens were repaired with suture tape and knotless anchors. Biomechanical analysis included displacement during cyclic loading over 250 cycles, construct stiffness, ultimate load to failure, and failure mode analysis. RESULTS: Compared with transosseous repairs, quadriceps tendons repaired with knotless suture tape demonstrated significantly less displacement during cyclic loading (cycles 1-20 3.6 ± 1.3 vs 6.3 ± 1.9 mm, P = .003; cycles 20-250 2.0 ± 0.4 vs 3.1 ± 0.9 mm, P = .011), improved construct stiffness (67 ± 25 vs 26 ± 12 N/mm, P = .001), and greater ultimate load to failure (616 ± 149 vs 413 ± 107 N, P = .004). Our repair technique also demonstrated improved biomechanical parameters compared with fully threaded suture anchor repair in initial displacement during cyclic loading (cycles 1-20 3.0 ± 0.8 vs 5.1 ± 0.9 mm, P < .001), construct stiffness (62 ± 20 vs 28 ± 10 N/mm, P = .001) and ultimate load to failure (579 ± 129 vs 399 ± 87 N, P = .006). CONCLUSIONS: Repair of quadriceps tendon ruptures with this knotless suture anchor with suture tape repair technique is biomechanically superior in cyclic displacement, construct stiffness, and ultimate load to failure compared with transosseous and fully threaded suture anchor techniques in cadaveric specimens. CLINICAL RELEVANCE: The demonstration that our repair technique is biomechanically superior to previously described techniques in a cadaveric setting suggests that consideration should be given to this technique.

Distal triceps knotless anatomic footprint repair is superior to transosseous cruciate repair: a biomechanical comparison.

PURPOSE: The purpose of this study was to evaluate the biomechanical properties of a method of repair using bone tunnels with multiple high-strength nonabsorbable sutures and one knotless suture anchor compared with the standard transosseous technique for repair of the distal triceps. METHODS: The triceps tendon footprint was measured in 18 cadaveric elbows (9 matched pairs), and a distal tendon rupture was created. Eighteen elbows (9 matched pairs) were randomly assigned to one of 2 repair groups: transosseous cruciate repair group or knotless anatomic footprint repair group. Cyclic loading was performed for a total of 1,500 cycles and displacement was measured. Data for load at yield and peak load were obtained. RESULTS: The average bony footprint of the triceps tendon was 466 mm(2). Cyclic loading of tendons from the 2 repair types showed that the knotless anatomic footprint repair produced less displacement when compared with the transosseous cruciate repair (P < .05). Load at yield and peak load were also greater in the knotless anatomic footprint repair group (P < .05). CONCLUSIONS: Distal triceps knotless anatomic footprint repair in a cadaveric model had a significantly higher load and cycle to failure when compared with the traditional transosseous cruciate repair and produced less repair site motion. CLINICAL RELEVANCE: The increased biomechanical strength and resistance to displacement at the tendon-bone interface may lead to improved clinical outcomes with the knotless anatomic footprint repair technique and warrants further clinical study.

Cannulated screw fixation of refractory olecranon stress fractures with and without associated injuries allows a return to baseball.

BACKGROUND: An olecranon stress fracture is a rare injury associated with valgus extension overload in baseball players. No long-term outcomes studies have been published documenting the results of surgical fixation of olecranon stress fractures with or without concomitant injuries in baseball players. HYPOTHESIS: Open reduction and internal fixation (ORIF) of an olecranon stress fracture will reliably produce bony union and allow a successful return to the previous level of activity in competitive baseball players. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-five patients treated with ORIF for an olecranon stress fracture at least 2 years earlier (range, 2-10.14 years) were retrospectively contacted to complete a telephone survey; 18 of 25 (72%) patients responded. Data were collected to determine the return to play rate, level of arm pain, and overall arm function. RESULTS: All 18 stress fractures went on to successful union; 17 of 18 (94%) athletes returned to baseball at or above their previous level. Average return to play time was 29 weeks. The numeric analog pain score was 0.2 at rest and 0.3 when throwing at the time of follow-up, at an average 6.2 years (range, 2.0-10.14 years) after surgery. The average score at follow-up on the disabilities of the arm, shoulder and hand outcome measure-shortened version (QuickDASH) was 4.1 (range, 0-27.3). Ten (56%) patients required 13 additional future surgeries on their throwing arm; 7 surgeries in 6 (33%) patients were not related to the index surgery. Six of 18 (33%) patients underwent hardware removal, with 2 (11%) for infection. CONCLUSION: Open reduction and internal fixation of olecranon stress fractures in competitive baseball players has a high rate of success in returning players to or above their former level of play and allows for good elbow function at an average of 6.2 years postoperatively. However, these patients are at high risk for additional future surgeries on their throwing arm.

Results of laboratory evaluation of acute knee effusion after anterior cruciate ligament reconstruction: what is found in patients with a noninfected, painful postoperative knee?

BACKGROUND: Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating complication. No normative data have been reported for knee aspiration after anterior cruciate ligament reconstruction in the early postoperative period. HYPOTHESIS: Determining normative laboratory data from a retrospective review of noninfected early postoperative anterior cruciate ligament reconstruction knee effusions will allow for the calculation of an aspirate white blood cell (WBC) threshold value indicative of infection. STUDY DESIGN: Case series (diagnosis); Level of evidence, 4. METHODS: A 2-year retrospective chart review of 151 anterior cruciate ligament reconstruction patients was performed. Thirty-one noninfected patients meeting the inclusion and exclusion criteria and 1 infected patient had laboratory data collected, including peripheral blood and knee effusion aspirate analyses. Laboratory data from pertinent published studies of infected knees after anterior cruciate ligament reconstruction were combined with the data of our 1 infected patient, establishing a historical control group. Data were analyzed and results were then compared. Infected aspirate WBC threshold value statistics were then calculated. RESULTS: Analysis of noninfected knee effusion aspirates revealed a mean WBC count of 9600/uL (standard deviation [SD], 15 200), and a mean of 66% polymorphonuclear (PMN) cells (SD, 34). Aspirate WBC 98% confidence interval (CI) was 2800/uL to 16 200/uL, and the 98% CI for PMN cells was 58% to 84%. Aspirate WBC count >16 200/uL is 86% sensitive, 92% specific, and has a positive likelihood ratio of 10.4 as an indicator of infection. CONCLUSION: Benign effusion after anterior cruciate ligament reconstruction is common and is associated with elevated inflammatory markers. When concerned, knee aspiration after anterior cruciate ligament surgery gives the highest yield to differentiate between a painful effusion and a septic knee in the early postoperative period while awaiting definitive culture results. The authors report confidence intervals defining the range of cell count variables for noninfected patients requiring aspiration, specifically WBC and PMN, and suggest a WBC threshold value of >16 200/uL be used as an indicator of infection. On the basis of comparison with historical control data, the authors believe these data are significant and will be reliable for clinical use.

Knee medial compartment contact pressure increases with release of the type I anterior intermeniscal ligament.

BACKGROUND: The anterior intermeniscal ligament of the knee is at risk during knee arthroscopy, anterior cruciate ligament reconstruction, and tibial nail insertion. HYPOTHESIS: Release of the anterior intermeniscal ligament, in knees with type I ligaments, will result in altered contact pressures in the medial compartment. STUDY DESIGN: Controlled laboratory study. METHODS: Five fresh-frozen human cadaveric knees with intact type I anterior intermeniscal ligaments were chosen for testing in a modified MTS machine from 0 degrees to 60 degrees of flexion under 2 conditions: (1) intact and (2) after sharp sectioning of the anterior intermeniscal ligament. Measurements were made using inframeniscal contact pressure sensors covering the medial compartment. Poststudy analysis was done in 10 degrees increments between 0 degrees and 60 degrees of flexion, looking at peak contact pressure and the amount of contact area seeing pressure. RESULTS: Sectioning of the anterior intermeniscal ligament caused a statistically significant increase in the peak pressure at 20 degrees , 30 degrees , 40 degrees , and 50 degrees of knee flexion. The largest change occurred at 40 degrees of knee flexion, when the peak pressure increased by 27.5% (3.68 MPa to 4.69 MPa). Contact area decreased, although this difference was not statistically significant. CONCLUSION: Release of the anterior intermeniscal ligament results in increased peak contact pressures in the medial compartment of the knee. CLINICAL RELEVANCE: Care should be taken to avoid sacrifice of this ligament during surgery.