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.

Diffusion tensor imaging of human Achilles tendon by stimulated echo readout-segmented EPI (ste-RS-EPI).

PURPOSE: Healing, regeneration, and remodeling of the injured Achilles tendon are associated with notable changes in tendon architecture. However, assessing Achilles microstructural properties with conventional diffusion tension imaging (DTI) remains a challenge because of very short T2 / T 2 * values of the tendon. Hence, the objective of this study was to develop a novel Achilles tendon DTI protocol for a non-invasive investigation of the changes of microstructural integrity in tendinopathy. METHODS: A novel stimulated echo readout-segmented EPI (ste-RS-EPI) DTI sequence was proposed to achieve a TE of ∼14-20 ms for typical b-values of 400-800 s/mm2 on clinical 3T MRI scanners. To further boost tendon MR signal, the Achilles was positioned at the magic angle (∼55 °) with respect to the scanner B0 field. The sensitivity of the developed protocol was evaluated in 19 healthy participants and 6 patients with clinically confirmed tendinopathy. RESULTS: Compared to spin echo RS-EPI DTI protocol, ste-RS-EPI provided an ∼100-200% increase in Achilles MR signal. Tendinopathic Achilles demonstrated a high degree of microstructural disruption based on DTI tractography analysis, with significantly lower (P < 0.05) axial diffusivity (1.20 ± 0.19 vs. 1.39 ± 0.10 × 10-3 mm2 /s), radial diffusivity (0.72 ± 0.11 vs. 0.81 ± 0.08 × 10-3 mm2 /s), and mean diffusivity (0.87 ± 0.14 vs. 1.00 ± 0.07 × 10-3 mm2 /s), but no significant difference in fractional anisotropy (0.38 ± 0.04 vs. 0.38 ± 0.05; P = 0.86). CONCLUSION: Achilles tendon ste-RS-EPI DTI can non-invasively detect the tendinopathy-induced changes to microstructural integrity, consistent with the disruption of collagen arrangement and increased cellularity. This study demonstrated the robustness and sensitivity of the proposed protocol in Achilles tendinopathy.

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.

Combined, Single-Anchor Subscapularis Tendon Repair and Proximal Biceps Tenodesis Leads to Improved Function and Decreased Pain at 1 Year.

Purpose: To evaluate the 1-year clinical outcomes of patients treated with combined proximal biceps tenodesis and repair of type II to III subscapularis tendon (SST) injuries according to Lafosse et al., using the Loop 'N' Tack (LNT) technique. Methods: All patients undergoing proximal biceps tenodesis and rotator cuff repair between March 1, 2020, and January 30, 2022, were retrospectively identified. Only patients undergoing combined proximal biceps tenodesis and repair of grade II or III SST injuries with a minimum follow-up of 1 year were included. All patients underwent combined single-anchor proximal biceps tenodesis and SST repair using the LNT technique. The following outcome scores were recorded at a final follow-up of 1 year postoperatively and compared with baseline, preoperative values: American Shoulder and Elbow Score (ASES), Single Assessment Numerical Evaluation (SANE), Veterans Rand 12 Item Health Survey (VR-12), and visual analog scale (VAS). The minimal clinically important difference (MCID) for all outcome indices was determined with a distribution-based method. Results: A total of 41 consecutive patients were included. The MCID values for VAS pain, ASES, SANE, and VR-12 mental scores were 0.97, 8.5, 10.9, and 6.0 respectively. At 1-year final follow-up, approximately 95% (39/41) of patients exceeded the MCID for VAS pain scores, 90% (37/41) of patients for ASES scores, 85.4% (34/41) of patients for SANE scores, and 75.6% (31/41) of patients for VR-12 mental health scores. On average, ASES and SANE scores improved by 37 (preoperatively: 45.2, 1 year: 82.4, P < .001) and 38 points (preoperatively: 38.0, 1 year: 75.7, P < .001), respectively, while VAS scores decreased by 4 points (preoperatively: 5.49, 1 year: 1.48, P < .001). Approximately 88% (36/41) of patients were satisfied at 1 year postoperatively. Treatment failure was observed in 1 patient (2.4%). Conclusions: Patients treated with combined, single-anchor SST repair and LNT proximal biceps tenodesis achieved significant improvements in function, high satisfaction, and low rates of reoperation at 1 year postoperatively. Additionally, 76% to 95% of patients met the MCID for VAS pain, ASES, SANE, and VR-12 mental health scores. Level of Evidence: Level IV, retrospective case series.

PET/MRI reveals ongoing metabolic activity in ACL grafts one year post-ACL reconstruction.

PURPOSE: To use serial PET/MRI imaging to radiographically evaluate the metabolic activity of the ACL graft over the first post-operative year. METHODS: Six patients undergoing primary ACL reconstruction were recruited in this prospective study in an inpatient university hospital. All patients underwent femoral and tibial suspensory cortical fixation with quadrupled semitendinosus autograft hamstring ACL reconstruction by an orthopaedic surgeon. Simultaneous 18F-FDG PET and MRI of both the operative and non-operative knee was performed at three, six, and 12 months post-operatively. Quantification of the mean standardized uptake value (SUV) within the whole-knee, as well as tibial tunnel, femoral tunnel, and intra-articular graft regions of interest (ROIs). RESULTS: PET whole-knee activity was increased at all time-points post-operatively compared to the control, non-operative knee. Activity decreased over time, yet considerable generalized activity remained 1 year post-operatively, with relative intensity 34% percent higher than control. When the operative knee was divided into three whole-regions, there was greater activity in the tibia at three than 12 months, the femur at six than 12 months, and in the tibia compared to the intra-articular region at 3 months. When they were separated into sub-regions, results demonstrated greater activity closer to the joint surface. CONCLUSIONS: PET/MRI evaluation of ACL graft reconstructions demonstrates evolving biologic activity within the graft and both tunnels. Focal areas of increased activity within the tunnels may indicate of ligamento-osseous morphologic changes. These data suggest that graft incorporation continues well beyond 1 year post-operatively. LEVEL OF EVIDENCE: Level IV.

An Arthroscopic Modification of Coracoclavicular Ligament Reconstruction and Distal Clavicle Fracture Fixation in the Lateral Position.

Distal clavicle fractures and acromioclavicular injuries are common shoulder injuries. Despite the frequency of these injuries, there is no gold standard for treatment. Recent suspensory fixation techniques have minimized the amount of hardware required for surgical treatment of both acromioclavicular separations and distal clavicle fractures. Advantages include reconstruction of ligamentous anatomy, minimal hardware irritation, earlier return to activity, and decreased need for hardware removal. These reconstructions are classically done in the beach chair position in an open fashion. Our preferred technique for treatment of unstable distal clavicle fractures and acromioclavicular injuries is arthroscopy-assisted coracoclavicular ligament reconstruction with or without distal clavicle fixation in the lateral decubitus position.

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.

Weightbearing ankle dorsiflexion range of motion and sagittal plane kinematics during single leg drop jump landing in healthy male athletes.

BACKGROUND: Passive ankle dorsiflexion range of motion (DROM) measures have been identified as a risk factor for injury during landings. However, passive measurements might not be indicative of dynamic ankle movement, whereas a weightbearing ROM might be a better tool when evaluating movement. The purpose of this study was to investigate the relationship between weightbearing DROM and sagittal plane landing mechanics in a single leg drop jump task. METHODS: Seventy-three male athletes (22.1±3.9 years old, height 186.2±11 cm, and weight 100.2±21.8 kg) performed bilateral modified-lunge tasks and bilateral single leg drop jump landings while 3D kinematic data were collected. Hip, knee, and ankle joint angles were calculated at initial contact (IC) maximum knee flexion (MKF), and total excursion (TE) during a single leg drop jump landing. RESULTS: No bilateral differences in DROM and single leg landing mechanics existed. Decreased ankle DROM was correlated to decreased ankle dorsiflexion at MKF (P=0.00) and TE (P=0.00) for both dominant and non-dominant limbs. Decreased ankle DROM was also correlated to decreased knee flexion at IC (P=0.00), MKF (P=0.00), and TE (P=0.1), for both dominant and non-dominant limbs. Ankle DROM correlated to hip flexion at MKF (r=0.25) and TE (r=0.30) in the dominant limb. CONCLUSIONS: Restrictions in DROM may contribute to a stiff landing with less flexion at the ankle and knee. These findings may be useful in designing training programs aimed at increasing DROM in order to improve an athlete's landing mechanics and decrease risk of injury.

The In Vivo Impact of Leukocyte Injections on Normal Rat Achilles Tendons: Potential Detriment to Tendon Morphology, Cellularity, and Vascularity.

In this study, we determine the in vivo effects of injecting sub-populations of leukocytes into normal rat Achilles tendons via a controlled laboratory study. Allogenic monocytes, granulocytes, or plasma were injected into 24 healthy rat Achilles tendons. Treated and contralateral un-treated control tendons then assessed for cellularity, histologic morphology, and vascularity after 7 and 14 days. Significant increases of 221% and 249% in cellularity (P = 0.014) were seen on day 14 within Achilles tendons injected with granulocytes as compared to plasma and monocytes, respectively. Also, significant improvement in morphology (P = 0.029) between days 7 and 14 was seen for the granulocyte injected Achilles tendons. Significant increases in cellularity after an injection of granulocytes, compared to monocytes and plasma, corresponds to a significant increase in inflammation within the tissue, suggesting that leukocyte-rich platelet-rich plasma (PRP) preparations are proinflammatory and potentially catabolic when injected into tendon tissue. The concentration and composition of white blood cells within PRP preparations is variable and needs to be better understood in order to optimize clinical utility of PRP injections.

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.

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.

Sagittal plane kinematic differences between dominant and non-dominant legs in unilateral and bilateral jump landings.

CONTEXT: In both research and clinical settings there is an assumption of symmetry between limbs in landing. However, development of a preferred limb side is a natural occurrence. It is not well established how limb dominance affects landing mechanics in a unilateral or bilateral landing. OBJECTIVE: To investigate sagittal plane mechanics between dominant and non-dominant legs in both unilateral and a bilateral landing tasks. DESIGN: Cross-sectional study. SETTING: Laboratory environment. PARTICIPANTS: 148 male athletes. MAIN OUTCOME MEASURES: Sagittal plane kinematics (hip, knee, and ankle flexion) at initial contact and maximum knee flexion, and total excursion of the movement. RESULTS: No significant differences were found between limbs in the unilateral landing. Knee flexion (p = 0.02) and hip flexion (p = 0.00) were significantly different between dominant and non-dominant limbs at initial contact in the bilateral landing. Knee flexion total excursion (p = 0.04) and hip flexion total excursion (p = 0.03) in the bilateral landing were also significantly different between limbs. CONCLUSIONS: Lower limb symmetry was observed for the unilateral landing. Minimal, yet significant, asymmetries (less than 2°) were present during the bilateral landing. This finding justifies the continued use of the dominant limb in research and clinical settings.

Distal triceps knotless anatomic footprint repair: a new technique.

Distal triceps rupture is a rare injury causing significant disability. Several techniques for treating distal triceps ruptures have been described using bone tunnels or suture anchors. More recent techniques have focused on re-creating the anatomic footprint of the distal triceps tendon. However, the increasing numbers of anchors used increase the risk to the articular surface, and all earlier techniques require knot tying and bulky knots beneath the thin posterior elbow soft-tissue envelope. We describe a technique combining the use of bone tunnels and a single suture anchor to create a knotless anatomic footprint repair of the distal triceps. By using this technique, we are able to create a tension-band construct that self-reinforces the anatomic repair and is very low profile while significantly decreasing risk to the articular surface.

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.