Suture Tape Augmentation Improves the Biomechanical Performance of Bone-Patellar Tendon-Bone Grafts Used for Anterior Cruciate Ligament Reconstruction.

PURPOSE: The purpose of this study was to investigate the time-zero biomechanical properties (stiffness, displacement, and load at failure) of bone-patellar tendon-bone (BTB) grafts used for anterior cruciate ligament (ACL) reconstruction with and without suture tape augmentation as a means to determine the potential clinical benefit of this technique. METHODS: Eight juvenile porcine knees underwent ACL reconstruction with a human cadaveric BTB graft (control). These were compared to 8 juvenile porcine knees that underwent ACL reconstruction with a BTB graft augmented with suture tape. All knees underwent biomechanical testing utilizing a dynamic tensile testing machine. Cyclic loading between 50-250N was performed for 500 cycles at 1 Hz to simulate in vivo ACL loads during the early rehabilitation phase. The grafts were displaced during load-at-failure tensile testing at 20 mm/min. Differences in graft displacement, stiffness, and load at failure for the control and suture tape augmented groups were compared with the Student t-test with a significance level of P < .05. RESULTS: There was no difference in graft displacement between the 2 groups. A 104% higher postcyclic stiffness was noted in the augmented group compared to the controls (augmentation: 261 ± 76 N/mm versus control 128 ± 28 N/mm, P = .002). The mean ultimate load at failure was 57% higher in the augmented group compared to controls (744 ± 219 N vs postcyclic 473 ± 169 N, respectively [P = .015]). There was no difference in mode of failure between the control knees and those augmented with suture tape, with approximately half failing from pull off of the tendon from the bone plug and half with pull out of the bone plug from the tunnel. CONCLUSION: Independent suture tape augmentation of a BTB ACL reconstruction grafts was associated with a 104% increase in graft stiffness and a 57% increase in load at failure compared to nonaugmented BTB grafts. CLINICAL RELEVANCE: In vivo suture tape augmentation of a BTB ACL reconstruction increases graft construct strength and stiffness, which may reduce graft failure in the clinical setting.

Sentinel lymph node biopsy is indicated for patients with thick clinically lymph node-negative melanoma.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is indicated for the staging of clinically lymph node-negative melanoma of intermediate thickness, but its use is controversial in patients with thick melanoma. METHODS: From 2002 to 2012, patients with melanoma measuring ≥4 mm in thickness were evaluated at a single institution. Associations between survival and clinicopathologic characteristics were explored. RESULTS: Of 571 patients with melanomas measuring ≥4 mm in thickness and no distant metastases, the median age was 66 years and 401 patients (70.2%) were male. The median Breslow thickness was 6.2 mm; the predominant subtype was nodular (45.4%). SLNB was performed in 412 patients (72%) whereas 46 patients (8.1%) presented with clinically lymph node-positive disease and 113 patients (20%) did not undergo SLNB. A positive SLN was found in 161 of 412 patients (39.1%). For SLNB performed at the study institution, 14 patients with a negative SLNB developed disease recurrence in the mapped lymph node basin (false-negative rate, 12.3%). The median disease-specific survival (DSS), overall survival (OS), and recurrence-free survival (RFS) for the entire cohort were 62.1 months, 42.5 months, and 21.2 months, respectively. The DSS and OS for patients with a negative SLNB were 82.4 months and 53.4 months, respectively; 41.2 months and 34.7 months, respectively, for patients with positive SLNB; and 26.8 months and 22 months, respectively, for patients with clinically lymph node-positive disease (P<.0001). The median RFS was 32.4 months for patients who were SLNB negative, 14.3 months for patients who were SLNB positive, and 6.8 months for patients with clinically lymph node-positive disease (P<.0001). CONCLUSIONS: With an acceptably low false-negative rate, patients with thick melanoma and a negative SLNB appear to have significantly prolonged RFS, DSS, and OS compared with those with a positive SLNB. Therefore, SLNB should be considered as indicated for patients with thick, clinically lymph node-negative melanoma.

Biomechanical Effect of Differential Tensioning on Suture-Augmented Ulnar Collateral Ligament Reconstruction of the Elbow.

BACKGROUND: Medial ulnar collateral ligament (mUCL) reconstructions are becoming increasingly prevalent among the overhand throwing population. Suture tape augmentation has the potential to provide biomechanical advantages over standard docking reconstruction. However, the optimal tensioning of the suture augmentation technique has not yet been evaluated. PURPOSE: To compare the subfailure biomechanical performance and graft strain of a standard docking mUCL reconstruction to an mUCL reconstruction using suture tape augmentation tensioned with 1 mm or 3 mm of laxity. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 18 cadaveric elbows were dissected to the mUCL anterior band and biomechanically assessed via a valgus torque protocol to failure. Elbows were randomly assigned to be reconstructed via (1) a standard docking technique, (2) a suture-augmented reconstruction with 1-mm laxity, or (3) a suture-augmented reconstruction with 3-mm laxity. Reconstructed elbows were then subjected to the same loading protocol. Subfailure mechanical properties, failure mode, and mUCL/palmaris strain were assessed. RESULTS: All reconstruction groups had decreased rotational stiffness, torque at 5° of angular rotation, and resilience compared with matched native controls. There were no differences in transition torque between groups. The failure mode of suture-augmented specimens was most often due to bone tunnel failure or reaching the maximum allowable angular displacement. In native controls or docking reconstructions, the primary failure mechanism was in the ligament or graft midsubstance. There were no significant differences in strain on the reconstructed or suture-augmented groups at any laxity compared with native controls. CONCLUSION: Suture augmentation results in similar subfailure joint biomechanical properties as the standard docking reconstruction procedure at both laxity levels in a cadaveric model. There are improvements in the failure mode of suture-augmented specimens compared with standard docking. Graft strain may be modestly reduced in the 1-mm laxity group compared with other reconstruction groups. CLINICAL RELEVANCE: Suture augmentation at both 1-mm and 3-mm laxity appears to offer similar advantages in subfailure biomechanics to standard docking reconstruction of the mUCL, with some improvements associated with failure mode. Strain data suggest a potential avoidance of graft stress shielding when tensioning the suture augmentation to 3-mm laxity, which is not as apparent with 1-mm laxity.

Lower Extremity Muscle Injuries in the Overhead Athlete.

PURPOSE OF REVIEW: Lower extremity (LE) injuries are a common source of disability and time-loss for overhead athletes, and muscles have been found to be the predominant soft tissue structure affected. The current review highlights the orthopaedic literature examining lower extremity muscle injuries in overhead athletes in regard to epidemiology, diagnosis, and conventional and emerging treatment measures. RECENT FINDINGS: The hamstring muscles have been found to be the most commonly injured lower extremity muscle group in professional baseball, followed by the adductors, quadriceps, iliopsoas, and gastrocnemius-soleus complex. Strains and contusions comprise over 90% of these muscle injuries. Various advanced imaging grading systems have been developed to help characterize the nature of a muscle injury, although a clear and consistent prognostic utility of these systems is still unclear. The vast majority of lower extremity muscle injuries in overhead athletes are managed nonoperatively, and there is promising data on the use of emerging treatments such as platelet-rich plasma and blood flow restriction therapy. Lower extremity muscle injuries-often referred to as strains-are a relatively common issue in high-demand overhead athletes and can be a significant source of time-loss. Within baseball, position players are affected far more often than pitchers, and sprinting and fielding are the most common activities leading to strains. Magnetic resonance imaging (MRI) is considered the gold standard imaging modality to evaluate these muscle injuries and will allow for a detailed assessment of tissue damage. Nonetheless, return-to-play is often dictated by a given athlete's progression through a nonoperative rehabilitation protocol, with surgical intervention reserved for less common, select injury patterns.

Rod fractures and nonunions after long fusion to the sacrum for primary presentation adult spinal deformity: a comparison with and without interbody fusion in the distal lumbar spine.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To investigate the prevalence and incidence rate of rod fractures (RF) in patients undergoing surgery for correction of adult spinal deformity (ASD) with or without the use of interbody fusions in the caudal levels of the fusion construct. BACKGROUND: Data: Pseudarthrosis and rod fracture after long spinal fusion to the sacrum for correction of ASD remain a concern. METHODS: We reviewed clinical records of patients who underwent surgery for correction of ASD between 2004 and 2014. All cases were primary (no prior spine fusion) surgeries with long fusion to the sacrum and bilateral spinopelvic fixation. Patients were dichotomized into one of two groups based on whether an interbody fusion was performed at the caudal levels of the fusion construct. The primary outcome of interest was the prevalence and incidence rate of RFs. RESULTS: A total of 230 patients underwent a long segment fusion for correction of ASD with mean follow-up of 55 months. 117 patients had an interbody fusion (IF) while 113 patients did not (NIF). At last follow-up, there was no significant difference in the prevalence of RFs between the cohort of patients IF vs NIF (IF cohort: n = 20, 17.9% vs NIF cohort: n = 15, 14.2%, p = 0.49). However, the incidence rate for bilateral rod fractures was 1.6%/year for IF group vs 1.0%/year for NIF group (p = 0.02). Location of RF was different between the two groups; RF (unilateral and bilateral) above L4 was the most common location in the IF group (n = 17/20; 85%) compared to L4-S1 in the NIF group (n = 11/15; 73%) (p = 0.02). CONCLUSION: Interbody fusion does not fully protect against rod failure in the lumbar spine in ASD patients with long posterior spinal fusion and may encourage failure at L2-L4, the levels above the interbody fusion. LEVEL OF EVIDENCE: III.

Comparison of rod fracture rates in long spinal deformity constructs after transforaminal versus anterior lumbar interbody fusions: a single-institution analysis.

OBJECTIVE: Pseudarthrosis is a common complication of long-segment fusions after surgery for correction of adult spinal deformity (ASD). Interbody fusions are frequently used at the caudal levels of long-segment spinal deformity constructs as adjuncts for anterior column support. There is a paucity of literature comparing rod fracture rates (proxy for pseudarthrosis) in patients undergoing transforaminal lumbar interbody fusion (TLIF) versus anterior lumbar interbody fusion (ALIF) at the caudal levels of the long spinal deformity construct. In this study the authors sought to compare rod fracture rates in patients undergoing surgery for correction of ASD with TLIF versus ALIF at the caudal levels of long spinal deformity constructs. METHODS: We reviewed clinical records of patients who underwent surgery for correction of ASD between 2008 and 2014 at a single institution. Data including demographics, comorbidities, and indications for surgery, as well as postoperative variables, were collected for each patient. All patients had a minimum 2-year follow-up. Patients were dichotomized into two groups for comparison on the basis of undergoing a TLIF versus an ALIF procedure at the caudal levels of long spinal deformity constructs. The primary outcome of interest was the rate of rod fractures. RESULTS: A total of 198 patients (TLIF 133 patients; ALIF 65 patients) underwent a long-segment fusion to the sacrum with iliac fixation. The mean ± standard deviation follow-up period was 62.23 ± 29.26 months. Baseline demographic variables were similar in both patient groups. There were no significant differences between groups in the severity of the baseline sagittal plane deformity (i.e., baseline lumbar-pelvic parameters) or the final deformity correction achieved. Mean total recombinant human bone morphogenetic protein 2 (rhBMP-2) dose for L1-sacrum fusion was significantly higher in the ALIF (100 mg) than in the TLIF (62 mg) group. The overall rod failure rate (cases with rod fracture/total cases) within this case series was 19.19% (38/198); 10.60% (21/198) were unilateral rod fractures and 8.58% (17/198) were bilateral rod fractures. At last clinical follow-up, there were no statistically significant differences in bilateral rod fracture rates between the group of patients who had a TLIF procedure and the group who had an ALIF procedure at the caudal levels of the long spinal deformity constructs (TLIF 10.52% vs ALIF 4.61%, p = 0.11). However, the incidence rate (cases per patient follow-up years) for bilateral rod fractures was significantly higher in the TLIF than in the ALIF cohort (TLIF 2.20% vs ALIF 0.70%, p < 0.0001). The reoperation rate for rod fractures was similar between the patient groups (p = 0.40). CONCLUSIONS: Although both ALIF and TLIF procedures at the caudal levels of long spinal deformity constructs achieved similar and satisfactory deformity correction, ALIFs were associated with a lower rod fracture incidence rate. There were no differences between groups in the prevalence of rod fracture or revision surgery, however, and both groups had low bilateral rod fracture prevalence and incidence rates. One technique is not clearly superior to the other.