Editorial Commentary: Tranexamic Acid Shown to Not Inhibit Healing Following Rotator Cuff Repair in Rats.

As use of tranexamic acid (TXA) to decrease operative bleeding has increased during various orthopaedic surgical procedures, there has been corresponding increased interest regarding additional potential benefits-and also potential risks-of its use. By lessening bleeding during and shortly after arthroscopic surgery, some potential benefits include less postoperative pain, less hemarthrosis, and subsequent decreased formation of scar adhesions, resulting in less permanent stiffness. However, use of this pharmacologic agent also raises the possibility of negative effects upon tissue healing. In a rat rotator cuff repair model, no lasting significant benefit was associated with TXA administration, including no long-term decreased adhesions or stiffness. On the other hand, no adverse effects regarding healing were noted with TXA.

International Knee Documentation Committee Radiographic Knee Joint Grading More Reliable Than Kellgren-Lawrence Grading and Other Grading Systems.

Kellgren-Lawrence grading appears to have become the de facto standard for reporting radiographic degeneration of knees, yet the much later-introduced and knee-specific International Knee Documentation Committee system has repeatedly been shown to have higher reliability. Although International Knee Documentation Committee radiographic grading does have limitations-especially in cases of severe gonarthrosis-it appears to be the most reliable current system suitable for the purposes of arthroscopic knee surgeons, and it was designed to encompass all 3 knee compartments. Posterior-anterior weight-bearing radiographs taken at approximately 45° of knee flexion have repeatedly been shown to be more sensitive for revealing tibiofemoral degeneration than standard anterior-posterior weight-bearing views at or near full extension.

Editorial Commentary: Subacromial Bursa May Possess Mesenchymal Progenitor Cells.

Subacromial bursal tissue biopsied during arthroscopic surgery for full-thickness rotator cuff tears appears to possess mesenchymal progenitor cells. Although attempting to harvest mesenchymal progenitor cells from the subacromial bursa for therapeutic purposes may currently be premature, the presence of these cells in bursal tissue does call into question the routine practice of subacromial bursectomy. To maximize the chances of healing after rotator cuff repair, perhaps it would be best to avoid excising non-diseased-appearing bursal tissue any more than what is absolutely necessary to facilitate visualization.

Editorial Commentary: Treatment Efficacy Found in Animal Studies May Not Translate to Humans.

Efficacy of low-intensity pulsed ultrasonography (LIPUS) has been demonstrated in several mammalian models of injury/repair of tendons, ligaments, and soft tissue-bone junctions. But human studies have not demonstrated benefit from such intervention. In addition to innate healing differences between humans and research animals, another reason for this outcome variance may be that animal investigations of LIPUS have so far focused on healing after acute intervention, whereas randomized clinical trials have only looked at treating chronic tendinopathy in symptomatic patients. On the basis of current animal data, potential clinical benefit of LIPUS is most likely to be demonstrated for addressing acute injuries or postoperative scenarios. Yet, a particularly important anatomic difference between humans and experimental land animals regarding ultrasonography is the presence of subcutaneous adipose in the former versus the lack thereof in the latter, especially in the extremities, because overlying adipose attenuates ultrasound waves directed at underlying injured, repaired, or reconstructed tissues.

Estimating Lengths of Semitendinosus and Gracilis Tendons by Magnetic Resonance Imaging.

PURPOSE: To determine whether preoperative magnetic resonance imaging (MRI) can help predict the tendon-only length of the semitendinosus (ST) and the gracilis (G). METHODS: The distance from the tibial insertion to the distal-most aspect of the musculotendinous junction (MTJ) of the ST and G was estimated on preoperative MRI scans of patients undergoing primary anterior cruciate ligament (ACL) reconstruction with single-bundle, quadruple-stranded hamstring autograft. This MRI tendon-only length, measured by a musculoskeletal radiologist blinded to surgical findings, was compared to the actual tendon-only length measured upon harvesting each tendon. RESULTS: Among the 42 patients comprising the study population, there was very strong correlation between the estimates of tendon-only length made by MRI and surgical measurements for both the ST (Spearman coefficient = 0.83; P < .0001) and the G (Spearman coefficient = 0.82; P < .0001). The difference between MRI and surgical measurements did not exceed 3 cm for any of the 84 harvested hamstring tendons. Bland-Altman plots confirmed agreement between the 2 measurement methods. There was also strong correlation between the surgically measured tendon-only length of the ST and its G counterpart (Spearman coefficient = 0.68; P < .0001). CONCLUSIONS: MRI estimates of tendon-only length for both the ST and G very strongly correlate with operative measurements of these lengths; the discrepancy between these 2 measurement methods was found to not exceed 3 cm when the MTJ of these tendons is visible on MRI scans. LEVEL OF EVIDENCE: Level III, comparative study.

Stability of two versus three peripheral pegs of the glenoid component in modern total shoulder arthroplasty.

PURPOSE: In total shoulder arthroplasty (TSA), the optimum number of peripheral pegs required for stability in the glenoid component is unknown. This study compared the stability of two versus three peripheral pegs in cemented glenoid components possessing a central press-fit peg. METHODS: Six unmodified glenoid components with three peripheral pegs, a large, central press-fit peg and six modified glenoid components with one inferior peripheral peg sharply removed were cemented into bone substitute polyurethane blocks. A modified rocking-horse test was completed by comparing superior- and inferior-edge displacement before and after 100,000 vertical motion cycles. Then, a torsional failure test applied 2 N axial load, followed by a rotational force to the glenoid component at 0.5 °/s until failure. RESULTS: Modified rocking-horse testing showed no statistically significant edge displacement at the superior or inferior aspect of the glenoid component before or after testing. During torsional testing, peak torque and degrees of rotation at failure also showed no significant difference. CONCLUSION: Two peripheral pegs offer equivalent stability as three peripheral pegs, as assessed by cyclic rocking and rotational failure testing. Fewer peripheral pegs during glenoid component implantation may lead to less dissection, less strain on soft tissues and decreased operative time.

Reliability and reproducibility of several methods of arthroscopic assessment of femoral tunnel position during anterior cruciate ligament reconstruction.

PURPOSE: To assess interobserver and intraobserver agreement of estimating anterior cruciate ligament (ACL) femoral tunnel positioning arthroscopically using circular and linear (noncircular) estimation methods and to determine whether overlay template visual aids improve agreement. METHODS: Standardized intraoperative pictures of femoral tunnel pilot holes (taken with a 30° arthroscope through an anterolateral portal at 90° of knee flexion with horizontal being parallel to the tibial surface) in 27 patients undergoing single-bundle ACL reconstruction were presented to 3 fellowship-trained arthroscopists on 2 separate occasions. On both viewings, each surgeon estimated the femoral tunnel pilot hole location to the nearest half-hour mark using a whole clock face and half clock face, to the nearest 15° using a whole compass and half compass, in the top or bottom half of a linear quadrant, and in the top or bottom half of a linear trisector. Evaluations were performed first without and then with an overlay template of each estimation method. RESULTS: The average difference among reviewers was quite similar for all 4 circular methods with the use of visual aids. Without overlay template visual aids, pair-wise κ statistic values for interobserver agreement ranged from -0.14 to 0.56 for the whole clock face and from 0.16 to 0.42 for the half clock face. With overlay visual guides, interobserver agreement ranged from 0.29 to 0.63 for the whole clock face and from 0.17 to 0.66 for the half clock face. The quadrant method's interobserver agreement ranged from 0.22 to 0.60, and that of the trisection method ranged from 0.17 to 0.57. Neither linear estimation method's reliability uniformly improved with the use of overlay templates. Intraobserver agreement without overlay templates ranged from 0.17 to 0.49 for the whole clock face, 0.11 to 0.47 for the half clock face, 0.01 to 0.66 for the quadrant method, and 0.20 to 0.57 for the trisection method. Use of overlay templates did not uniformly improve intraobserver agreement for any estimation method. CONCLUSIONS: There does not appear to be any advantage of using a half clock face or compass for estimating femoral tunnel position compared with a whole clock-face analogy. Visual reference aids appear to improve interobserver agreement (reliability) of circular analogies. The linear quadrant appears to be the most reliable method (fair to moderate agreement) for estimating femoral tunnel position without a visual aid for reference, but even better reliability, ranging from fair to good agreement, may be obtained by using the whole clock-face analogy with a visual aid. CLINICAL RELEVANCE: Increasing femoral tunnel position reliability may improve outcomes of ACL reconstruction surgery.

Femoral tunnel length: accessory anteromedial portal drilling versus transtibial drilling.

PURPOSE: To determine whether drilling using an anteromedial portal technique during single-bundle anterior cruciate ligament (ACL) reconstruction risks creating femoral tunnels less than 25 mm long in the clinical setting. METHODS: Intraoperative measurements of femoral tunnel length in a group of 35 consecutive patients undergoing single-bundle primary ACL reconstruction with transtibial (TT) femoral drilling were compared with a subsequent group of 80 consecutive patients undergoing the same procedure with accessory anteromedial portal (AAMP) femoral drilling. The length of femoral tunnels created through the AAMP in male patients was compared with that in female patients, and the expected likelihood of obtaining tunnels shorter than 25 mm was determined for either gender. RESULTS: The mean femoral tunnel length in the AAMP group was significantly shorter than that in the TT group (35.6 mm and 40.7 mm, respectively; P < .0001). In male patients in the AAMP group, the femoral tunnel length was significantly greater on average than that in female patients in the same group (36.8 mm and 33.5 mm, respectively; P = .0001). The shortest measured femoral tunnel was 28 mm long. The statistical likelihood of femoral tunnels created by AAMP drilling being less than 25 mm in length was 0.47% for female patients and 0.1% for male patients. CONCLUSIONS: Although femoral tunnel length with AAMP drilling is, on average, approximately 5 mm (12.5%) shorter than with TT drilling, the likelihood of the tunnel being too short to allow for suspensory fixation with adequate graft placed within the femoral tunnel is very low. Female patients undergoing single-bundle ACL reconstruction with AAMP drilling have a femoral tunnel length that is approximately 3 mm (9%) shorter than that in male patients on average, but the expected likelihood of obtaining a tunnel shorter than 25 mm in female patients is still less than 1:200, compared with 1:1,000 for male patients. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Intra-tunnel fixation versus extra-tunnel fixation of hamstring anterior cruciate ligament reconstruction: a meta-analysis.

Hamstring anterior cruciate ligament (ACL) reconstructions fixed inside both bone tunnels have a shorter initial working length, and thus should be stiffer than those fixed outside both bone tunnels. We used meta-analysis to compare 4-stranded hamstring ACL reconstructions using the 2 fixation methods with reconstructions using patellar tendon autografts. A Medline database search of English-language articles published through June 2004 yielded 36 studies that met the inclusion criteria: 5 intratunnel fixation studies (569 patients), 10 extra-tunnel fixation studies (604 patients), and 24 patellar tendon studies (1592 patients). Three studies included both patellar tendon and hamstring reconstructions. Demographically, all 3 groups were similar. There was no significant difference in the percentage of knees restored to normal instrumented laxity measurements between the 3 groups, nor was there a difference in graft failure rate. Patient satisfaction and return to preinjury activity rates were similar between the intratunnel fixation and patellar tendon groups and were significantly lower for the extra-tunnel fixation group. Good International Knee Documentation Committee scores did not correlate with good patient satisfaction or return to preinjury activity.

Arthroscopic findings in knees undergoing proximal tibial osteotomy.

This study determines the occurrence of significant, arthroscopically correctable intraarticular pathology at the time of valgus-producing high tibial osteotomy for symptomatic medial compartment arthrosis with varus malalignment. Thirty consecutive patients (32 knees) scheduled for the procedure underwent concomitant knee arthroscopy. In the lateral compartment, meniscal tears occurred in 16 knees (50%), unstable chondral flaps in 4 knees (13%), and loose bodies in 3 knees (9%). In the anterior compartment, unstable chondral flaps occurred in 10 knees (31%). In the medial compartment, meniscal tears occurred in 29 knees (91%). The 5 knees with mechanical symptoms did not demonstrate a higher occurrence of loose bodies, chondral flaps, or meniscal tears compared with knees without mechanical symptoms. There was a significant occurrence of correctable pathology in all three compartments in knees undergoing valgus-producing high tibial osteotomy for the treatment of symptomatic medial osteoarthritis with varus malalignment. Prior studies have not systematically documented these findings.

Classification of anterosuperior glenoid labrum variants and their association with shoulder pathology.

UNLABELLED: This prospective study of 367 consecutive shoulder arthroscopies assessed variants of the anterosuperior glenoid labrum and associated shoulder pathology. Thirty-three shoulders were excluded because of prior surgery, septic arthritis, or adhesive capsulitis. Anterosuperior glenoid variants were classified as: type I, cordlike middle glenohumeral ligament without sublabral foramen; type II, sublabral foramen without a cordlike middle glenohumeral ligament; type III, sublabral foramen with a cordlike middle glenohumeral ligament; and type IV, absent anterosuperior labrum with the anterior aspect of the superior labrum continuous with a cordlike middle glenohumeral ligament. The presence of these variants was correlated with the incidence of shoulder pathology found on arthroscopic inspection. Of 334 shoulders, 118 (35.3%) had variants of the anterosuperior glenoid labrum. Of these, 32 (27.1%) were type I, 27 (22.9%) were type II, 34 (28.8%) were type III, and 25 (21.2%) were type IV. The incidence of advanced superior labrum anterior-posterior lesions in the 86 shoulders displaying a type II, III, or IV variant was significantly higher than in shoulders with no anterosuperior variant (48.8% versus 23.6%, P<.001). Other pathologic findings were not significantly increased in shoulders with variants compared to those without. LEVEL OF EVIDENCE: Level 1.

Intraosseous innervation of the human patella: a histologic study.

BACKGROUND: The soft tissue structures surrounding the human knee joint have been the subject of extensive anatomic study. The detailed histologic findings within the bone of the human patella, however, have not been systematically studied. While the nerves supplied to the periarticular soft tissues have been very well documented, the nerves supplied to the interior of the bony patella have never been described. HYPOTHESIS: This study tests the hypothesis that the patella contains an intraosseous nerve network. Further, the authors investigate the anatomic location of these intraosseous nerves to better understand their possible clinical relevance. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten matched pairs of cadaveric patellae (left and right patellae from the same individual; 20 total) were prepared for evaluation by hematoxylin and eosin staining using a technique that allows the creation of complete, large histologic sections of individual patellae. The matched specimens were dissected free of soft tissue and then sectioned using a diamond-wafering saw into 3-mm sagittal (left patella) and transverse (right patella) sections. Sections were then decalcified and whole-mounted into paraffin blocks for further sectioning using a large-format microtome. All 20 specimens were prepared for evaluation. Age at death averaged 80 years (range, 64-91). All specimens demonstrated at least grade II chondromalacia. RESULTS: Nineteen of 20 (95%) specimens demonstrated intraosseous nerves. Of 248 sections studied, 116 (47%) demonstrated intraosseous nerves, with 227 individual nerves identified. The density of intraosseous nerves was greatest in the medial and central portions of the patella, with a significant paucity identified laterally. CONCLUSION: The primary intraosseous innervation of the patella derives from a medially based neurovascular bundle. CLINICAL RELEVANCE: A better understanding of the nerves within the human bony patella may improve understanding the patho-physiology of anterior knee pain syndromes.

Relationship of Musculotendinous Junction Location to Harvested Semitendinosus and Gracilis Tendon Length.

BACKGROUND: Harvested hamstring tendon length has received scant attention in published anterior cruciate ligament (ACL) reconstruction literature, yet length can limit the ability to increase graft diameter by folding the tendon over more than once. Indeed, some ultrashort tendons may be too short to yield a clinically useful graft after being folded over just once. Ultimately, the total length of a harvested hamstring tendon may depend on the length of the tendon distal to its musculotendinous (MT) junction. PURPOSE: To compare the lengths of harvested hamstring tendons to the location of the MT junction to help predict abnormally short tendon harvest. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Eighty-four consecutive patients undergoing primary ACL reconstruction using hamstring tendon autografts underwent intraoperative measurement of the total length of each harvested semitendinosus (ST) and gracilis (G) tendon, as well as the distance from the MT junction to that tendon's distal end (ie, the "tendon-only" length). RESULTS: The ratio of the tendon-only portion to total harvested tendon length averaged 0.52 (range, 0.39-0.71) for the ST and 0.52 (range, 0.43-0.71) for the G, suggesting a 95% chance of harvesting a tendon <15 cm in length for the tendon-only portion is <6.45 cm for ST or <6.75 cm for G tendons. There was moderate correlation between the lengths of harvested ST and G tendons with patient height as well as with the diameter of the combined, quadruple-stranded graft. CONCLUSION: The ratio of the tendon-only length to total harvested length for both the ST and G appear to range from approximately 0.4 to 0.7. Patients with abnormally distal MT junctions of either their ST or G are likely to have an abnormally short harvest of that tendon, even in the absence of technical harvesting error.

Deep venous thrombosis after knee arthroscopy: a meta-analysis.

PURPOSE: To better establish the incidence of deep venous thrombosis (DVT) after knee arthroscopy without prophylaxis. TYPE OF STUDY: Meta-analysis. METHODS: A MEDLINE search was performed to find published English-language studies of DVT following knee arthroscopy. Strict inclusion criteria required any investigation included for analysis to (1) be prospective, (2) include a population not given any antithrombotic prophylaxis, (3) perform universal screening of the lower extremity venous system using either ultrasound or venography, and (4) include a discrete population limited to unilateral arthroscopic knee surgery, exclusive of ligament surgery or open procedures. The results of the venographic studies were given additional weight mathematically to account for the increased sensitivity of this imaging modality compared with ultrasound in detecting DVT in asymptomatic lower extremities. RESULTS: The unprophylaxed patient populations in the 6 studies that met inclusion criteria ranged from 64 to 184 patients, and totaled 684. The total incidence rate of DVT in each study ranged from 3.1% to 17.9%, whereas the incidence rate of proximal DVT ranged from none detected to 4.9%. The total DVT rate was not related to the method of DVT detection, whereas proximal DVT was only noted in the 2 studies using contrast venography. Combining the 6 studies yields a total DVT incidence of 9.9% (95% confidence interval, 8.1%-11.7%), and a proximal DVT incidence of 2.1% (95% confidence interval, 1.2%-3.0%). CONCLUSIONS: DVT following knee arthroscopy is a consistent finding in studies of unprophylaxed patients when routine screening using ultrasound or contrast venography is used. Current data suggest an overall DVT rate of 9.9% and a proximal DVT rate of 2.1% after knee arthroscopy without antithrombosis prophylaxis. LEVEL OF EVIDENCE: Level II, Systematic Review of Levels I and II Diagnostic Studies.

Arthroscopic debridement of acute periprosthetic septic arthritis of the knee.

PURPOSE: To evaluate the efficacy of a treatment protocol including arthroscopic irrigation and debridement in resolving acute periprosthetic septic arthritis of the knee. TYPE OF STUDY: Retrospective review. METHODS: During a 1-year period, patients presenting with acute septic arthritis of the knee after total knee arthroplasty were screened for suitability for treatment with an arthroscopic debridement protocol consisting of (1) arthroscopic debridement and synovectomy with at least 12 L of antibiotic irrigant, (2) suction drainage until minimum output, (3) repeat arthroscopy for fever persisting beyond 48 hours, and (4) intravenous antibiotics for 6 weeks. Only previously well-functioning arthroplasties presenting within 7 days of symptom onset in patients without immunocompromising factors and with radiographically stable prosthetic components were selected for this treatment protocol. Five knees in 4 patients met the inclusion criteria and were examined clinically and radiographically at minimum 36-month follow-up. RESULTS: The mean follow-up interval was 41 months (range, 36 to 43 months). No knee had been revised or had revision planned for infection, although 1 had undergone tibial insert exchange for polyethylene wear. Follow-up radiographs showed no prosthetic loosening, and Knee Society scores averaged 88 (range, 75-95) in the 4 retained knees, 3 of which were subjectively thought to have returned to their preinfection level of functioning. All knees were infected with a single organism not considered highly virulent. No patients required oral suppressive antibiotics for their knees. CONCLUSIONS: Early aggressive arthroscopic debridement as part of a treatment protocol of acute periprosthetic knee septic arthritis with well-fixed and functioning implants can be an effective treatment option in selected cases. LEVEL OF EVIDENCE: Level IV study (no, or historical control group).

Quadriceps tendon impingement from a femoral interference screw.

Interference screws are a popular method of securing tendon grafts during anterior cruciate ligament reconstruction. This report describes the case of a patient with anterior knee pain, limited flexion, and partial-thickness tear of the quadriceps tendon caused by a protruding femoral interference screw following hamstring tendon anterior cruciate ligament reconstruction. The interference screw was radiolucent, requiring magnetic resonance imaging to visualize its location. Removal of the protruding portion of the interference screw and debridement of the partial-thickness tear of the quadriceps tendon led to rapid restoration of knee flexion and alleviation of the anterior knee pain.

Variants of the anterosuperior glenoid labrum and associated pathology.

PURPOSE: The study goal was to determine the incidence of the sublabral foramen and the Buford complex and to assess their association with superior labral pathology. TYPE OF STUDY: Prospective case series. METHODS: The surgical findings of 108 consecutive shoulder arthroscopies performed by the same surgeon were collected, along with patient demographics. During surgery, special attention was directed towards the anterosuperior labrum. The presence of a sublabral foramen or Buford complex was correlated with the morphology of the superior, middle, and inferior glenohumeral ligaments and the presence of superior labral pathology. RESULTS: A total of 20 shoulders (18.5%) were found to have a sublabral foramen, and 7 (6.5%) had the Buford complex. The incidence of significant SLAP lesions was significantly higher in these 27 shoulders than in the rest of the study population (56% v 12%, P <.005). A thick, cord-like middle glenohumeral ligament was significantly associated with the presence of a sublabral foramen (P <.005). CONCLUSIONS: The sublabral foramen and the Buford complex may be more common than previously thought. Furthermore, these variants of anterosuperior glenoid labrum anatomy appear to be associated with superior labral pathology. The presence of a cord-like middle glenohumeral ligament is associated with a sublabral foramen variant as well as the Buford complex.

Cyclic testing of arthroscopic knot security.

PURPOSE: Arthroscopic soft tissue repairs undergo many cycles of tensioning and relaxation before significant tissue healing occurs, and knot security under cyclic loads is essential for good results after these repairs. The current study was designed to assess the security of arthroscopic knots under stepwise cyclic loading. TYPE OF STUDY: In vitro materials testing. METHODS: Three types of arthroscopic knots--sliding knots with loop reversal but without post switching (S=SxSxSxS), modified Revo knots with loop reversal and post switching twice (S=S//xSxS//xS), and the SMC knot backed by 2 throws with loop reversal and post switching (S//xS//xS)--were compared with five-throw square knots tied with an open technique. All knots were tied with No. 2 braided nonabsorbable suture around 2 aluminum rods. They were pretensioned to 10 N, and initial displacement was recorded. The knots were then cycled at 1 Hz for 9 different load levels, with 250 cycles at each level, followed by a 30-second rest period to allow recording of permanent laxity of the suture loop. The first step of cyclic loading was from 10 to 40 N, and the upper limit was increased by 10 N for each successive load level. Any knot surviving cyclical loading was pulled to failure. RESULTS: Ten knots of each configuration were tested. All 3 arthroscopic slip knots showed significantly less initial displacement compared with the square knots (0.26 mm compared with 0.45 mm, respectively, P <.005). All square and modified Revo knots reached the ninth (120 N) loading level, whereas only 6 of the SMC knots and 3 of the arthroscopic knots without post switching reached the ninth loading level. Furthermore, all square and modified Revo knots failed by suture breakage at the knot, whereas 8 arthroscopic knots without post switching and 5 SMC knots failed by slipping. In fact, 3 of the arthroscopic knots without post switching and 1 of the SMC knots failed during the initial cyclic loading from 10 to 40 N. The modified Revo knots reached 3 mm of permanent laxity at significantly higher load levels than the square knots tied with an open technique (96 N v 78 N, P <.005). The SMC knots reached 3 mm of permanent laxity at statistically similar load levels compared with the square knots, but showed considerably more variability. None of the arthroscopic knots without post switching survived the entire cyclic-loading protocol. Four square, 5 modified Revo, and 5 SMC knots that survived cyclic loading reached ultimate failure at statistically similar load levels (157, 156, and 152 N, respectively). CONCLUSIONS: Post switching and loop reversal are key to arthroscopic knot security. Arthroscopic slip knots may be tighter at the time of knot construction than openly hand-tied square knots. The modified Revo knots appear to be as durable as openly hand-tied square knots regarding resistance to loosening under cyclic loading conditions. Security of arthroscopic knots without post switching is quite variable, making these knots less reliable. The SMC knot also proved not to be as reliable as the square and modified Revo knots when cyclically tested.