Interference Screw Fixation Research Articles

Clinical Results of Hamstring Autografts in Anterior Cruciate Ligament Reconstruction: A Comparison of Femoral Knot/Press-Fit Fixation and Interference Screw Fixation

To compare the clinical outcomes of femoral knot/press-fit anterior cruciate ligament (ACL) reconstruction with conventional techniques using femoral interference screws. Among patients who underwent arthroscopic ACL reconstruction with hamstring autografts, 73 were treated with either a femoral knot/press-fit technique (40 patients, group A) or femoral interference screw fixation (33 patients, group B). The clinical results of the 2 groups were retrospectively compared. The inclusion criteria were primary ACL reconstruction in active patients. The exclusion criteria were fractures, multiligamentous injuries, patients undergoing revision, or patients with contralateral ACL-deficient knees. In the femoral knot/press-fit technique, semitendinosus and gracilis tendons were prepared as 2 loops with knots. After passage through a bottleneck femoral tunnel, the grafts were fixed with a press-fit method (grafts' knots were stuck in the bottleneck of the femoral tunnel). A tie with Mersilene tape (Ethicon, Somerville, NJ) over a bone bridge for each tendon loop and an additional bioabsorbable interference screw were used for tibial fixation. The mean follow-up period was 38 months (range, 24 to 61 months). A significant improvement in knee function and symptoms was reported in most patients, as shown by improved Tegner scores, Lysholm knee scores, and International Knee Documentation Committee assessments (P < .01). The results of instrumented laxity testing, thigh muscle assessment, and radiologic assessment were clearly improved when compared with the preoperative status (P < .01). No statistically significant difference in outcomes could be observed between group A and group B (P= not significant). In this nonrandomized study, femoral knot/press-fit ACL reconstruction did not appear to provide increased anterior instability compared with that of conventional femoral interference screw ACL reconstruction. Favorable outcomes with regard to knee stability and patient satisfaction were achieved in most of our ACL-reconstructed patients using femoral knot/press-fit fixation with hamstring tendon autograft. Level IV, therapeutic case series.

Management of intraoperative complications in arthroscopic primary anterior cruciate ligament reconstruction.

Arthroscopic anterior cruciate ligament reconstruction is a commonly performed procedure which is technically demanding and involves multiple surgical steps with the potential for a wide range of intraoperative complications. In this article, we review these potential complications and give algorithms for dealing with them based on our experience and published evidence. We discuss the use of both bone-patellar tendon-bone and hamstring grafts and examine complications associated with suspensory button and interference screw fixation.

Interference screw versus Endoscrew fixation for anterior cruciate ligament reconstruction: A biomechanical comparative study in sawbones and porcine knees

Interference screw fixation is one of the most common methods for ligament reconstruction. Although the advantages and clinical outcomes of this procedure have been widely reported, post-surgical complications often arise. The purpose of this study was to evaluate a new femoral fixation device, the Endoscrew, for anterior cruciate ligament (ACL) reconstruction. We performed a mechanical test in accordance with American Society for Testing and Materials (ASTM) standards and an in vitro biomechanical study. An axial pullout test was conducted to evaluate the mechanical properties of the new device and the interference screw when implanted in solid rigid polyurethane foam test blocks. The biomechanical test used porcine femora to evaluate the initial fixation strength between these two implants. The maximum pullout force of the interference screw group [722.05 ± 130.49 N (N)] was significantly greater ( p < 0.01) than the Endoscrew group (440.79 ± 26.54 N) when implanted in polyurethane foam 320 kg/m 3 density. With polyurethane foam 160 kg/m 3 density, the maximum pullout forces were (242.61 ± 37.36 N) ( p < 0.001) and (99.33 ± 30.01 N) for the interference screw group and Endoscrew group, respectively. In the in vitro mechanical study, the Endoscrew (646.39 ± 72.38 N) required a significantly greater ultimate load prior to failure ( p < 0.05) when compared with the interference screw (489.72 ± 138.64 N). With regard to pullout stiffness, there was no statistically significant difference ( p < 0.13) between the Endoscrew group (99.15 ± 12.16 N/mm) and the interference screw group (87.96 ± 11.12 N/mm). The cyclic stiffness was also not significantly different ( p < 0.44) between the Endoscrew group (93.09 ± 16.07 N/mm) and the interference screw group (85.78 ± 14.76 N/mm). The axial pullout test showed that the strength of the Endoscrew was close to the fixation strength required for daily activities, but it is inappropriate for use in osteoporotic patients. The in vitro study showed that the Endoscrew has a superior initial mechanical fixation over the biodegradable interference screw.

Proximal Biceps Tenodesis: An Anatomic Study and Comparison of the Accuracy of Arthroscopic and Open Techniques Using Interference Screws.

Purpose:To (1) better define the anatomy of the proximal shoulder in relation to the long head of the biceps tendon, (2) compare the length-tension relationship of the biceps tendon in the native shoulder with that after arthroscopic and open tenodesis techniques using interference screws, and (3) provide surgical recommendations for both procedures based on study findings.Study Design:Descriptive laboratory study.Methods:Twenty fresh-frozen cadaveric shoulders were dissected for analysis. Initial anatomic measurements involving the proximal long head of the biceps tendon (BT) were made, which included: the labral origin to the superior bicipital groove (LO-SBG), the total tendon length (TTL), the musculotendinous junction (MTJ) to the inferior pectoralis major tendon border, the MTJ to the superior pectoralis major tendon border, and the biceps tendon diameter (BTD) at 2 different tenodesis locations. These same measurements were made again after completing a simulated suprapectoral arthroscopic and open subpectoral tenodesis, both with interference screw fixation. Statistical comparisons were then made between the native anatomy and that after tenodesis, with the goal of assessing the accuracy of re-establishing the normal length-tension relationship of the long head of the BT after simulated arthroscopic suprapectoral and open subpectoral tenodesis with tenodesis screws.Results:For all cadavers, the mean TTL was 104.1 mm. For the arthroscopic suprapectoral technique, the mean LO-SBG was 33.6 mm, and the mean tendon resection length was 12.8 mm in males and 5.0 mm in females. The mean BTD was 6.35 mm at the arthroscopic suprapectoral tenodesis site and 5.75 mm at the open subpectoral tenodesis site. Males were found to have statistically longer TTL and LO-SBG measurements (111.6 vs 96.5 mm [P = .027] and 37.2 vs 30.0 mm [P = .009], respectively). In the native shoulder, the mean distances from the MTJ to the superior and inferior borders of the pectoralis major tendon were 23.8 and 31.7 mm, respectively. No statistically significant differences were found in the location of the MTJ after simulated arthroscopic or open tenodesis with tenodesis screws as compared with the native shoulder. Mean hole depth in the open subpectoralis tenodesis was 22.4 mm (males) and 18.6 mm (females), with a mean of 20.5 mm for both sexes.Conclusion:This study better defines the anatomy of the proximal shoulder in relationship to the long head of the BT. Using our surgical techniques and recommendations, both arthroscopic and open tenodesis procedures adequately restored the native length-tension relationship of the long head of the biceps. Surgical recommendations are as follows: For arthroscopic suprapectoral tenodesis with tenodesis screws, the anatomic landmark of the SBG should be used. The tendon resection length should be approximately 1 cm in males and 5 mm in females when using a 25-mm tunnel. For subpectoral tenodesis, the site of tenodesis should be placed approximately 3 cm above the inferior border of the pectoralis major tendon in the bicipital groove; whipstitching and preserving approximately 2 cm of the biceps tendon above the MTJ is also recommended. The diameter of the screws in either location should be based on patient anatomy. However, this study shows the need for slightly longer screws for the subpectoral tenodesis, as the average hole depth was 20.5 mm. The system used in this study has 7 × 10–mm and 8 × 12–mm screws available. Based on study findings, a screw length of 15 to 18 mm may be needed.

Complications after subpectoral biceps tenodesis using a dual suture anchor technique.

Purpose:A variety of fixation techniques for subpectoral biceps tenodeses have been described including interference screw and suture anchor fixation. Biomechanical data suggests that dual suture anchor fixation has equivalent strength compared to interference screw fixation. The purpose of the study is to determine the early complication rate after subpectoral biceps tenodesis utilizing a dual suture anchor technique.Materials and Methods:A total of 103 open subpectoral biceps tenodeses were performed over a 3-year period using a dual suture anchor technique. There were 72 male and 31 female shoulders. The average age at the time of tenodesis was 45.5 years. 41 patients had a minimum of 6 months clinical follow-up (range, 6 to 45 months). The tenodesis was performed for biceps tendonitis, superior labral tears, biceps tendon subluxation, biceps tendon partial tears, and revisions of prior tenodeses.Results:There were a total of 7 complications (7%) in the entire group. There were 4 superficial wound infections (4%). There were 2 temporary nerve palsies (2%) resulting from the interscalene block. One patient had persistent numbness of the ear and a second patient had a temporary phrenic nerve palsy resulting in respiratory dysfunction and hospital admission. One patient developed a pulmonary embolism requiring hospital admission and anticoagulation. There were no hematomas, wound dehiscences, peripheral nerve injuries, or ruptures. In the sub-group of patients with a minimum of 6 months clinical follow-up, the only complication was a single wound infection treated with oral antibiotics.Conclusions:Subpectoral biceps tenodesis utilizing a dual suture anchor technique has a low early complication rate with no ruptures or deep infections. The complication rate is comparable to those previously reported for interference screw subpectoral tenodesis and should be considered as a reasonable alternative to interference screw fixation.Level of Evidence:Level IV-Retrospective Case Series

A Comparison of Functional Outcomes After Metallic and Bioabsorbable Interference Screw Fixations in Arthroscopic ACL Reconstructions.

Anterior Cruciate Ligament (ACL) is as one of the most frequently injured ligaments in the modern contact sports scenario. Graft fixations can be achieved during anterior cruciate ligament (ACL) reconstructions by using either bioabsorbable screws or metal screws. The objective of this study was to compare the functional outcomes after bioabsorbable and metallic interference screw fixations in arthroscopic anterior cruciate ligament reconstructions done by using hamstring grafts. This was a prospective, randomized study. Patients in Group 1 received bioabsorbable interference screws and patients in Group 2 received metallic interference screws. Arthroscopic assisted, anterior cruciate ligament reconstructions with the use of hamstring grafts which were fixed proximally with endobuttons and distally with bioabsorbable or metallic interference screws, were undertaken. Progress in functional outcomes was assessed by using Mann Whitney U- test. Functional outcomes in the two groups were compared by using independent t-test. In each group, there were statistically significant improvements in functional outcomes over successive follow-ups, which were seen on basis on Mann-Whitney U-test. The comparison of functional outcomes between the two groups, done by using independent t-test, showed no statistically significant differences between the two groups at 3 months, 6 months and 1 year of follow-up. p-value <0.05 was considered to be significant in our study. In our prospective study of comparison of functional outcomes between bioabsorbable and metallic interference screws in arthroscopic anterior cruciate ligament reconstuctions, which were evaluated by using Tegner activity scale and Lysholm knee scoring scale for a period of 1 year, no statistically significant difference was found. However, further authentication is required by doing long term studies.

Metallic or bioabsorbable interference screw for graft fixation in anterior cruciate ligament (ACL) reconstruction?

Approximately 100,000 anterior cruciate ligament (ACL) reconstructions are performed in the USA each year. Interference screw fixation is considered the standard for rigid fixation of the graft and provides higher fixation strength compared with other devices such as staples or buttons. The present study summarizes the latest evidence comparing the effectiveness of the available classes of interference screws for fixation of ACL grafts. A comprehensive search of the CINAHL, PubMed, Google Scholar, Embase Biomedical databases and the Cochrane Central Registry of Controlled Trials was performed in March 2013. Twelve studies met our inclusion criteria. Most studies showed no intergroup difference in terms of outcomes measured with validated clinical scores such as IKDC (International Knee Documentation Committee), Lysholm score and Tegner activity level. There was no significant difference regarding range of motion. Knee stability as evaluated with pivot shift and KT arthrometer showed a significant difference only in one study, favouring metallic interference screws. Tunnel widening is much more evident and marked patients who underwent ACL reconstruction with bioabsorbable screws, with no influence on the final clinical results achieved. Complication rates between the two screw classes were similar. The average modified Coleman methodology score was 74.67. AREAS OF UNCERTAINTY/RESEARCH NEED: The data comparing the outcomes achieved by two different materials for fixation, bioabsorbable and metallic, to be used during single-bundle ACL reconstruction, showed no significant difference in the final patient outcomes, in terms of clinical scores, clinical evaluation and imaging.

Tibial inlay press-fit fixation versus interference screw in posterior cruciate ligament reconstruction

Reconstruction of the posterior cruciate ligament (PCL) by a tibial press-fit fixation of the patellar tendon with an accessory bone plug is a promising approach because no foreign materials are required. Until today, there is no data about the biomechanical properties of such press-fit fixations. The aim of this study was to compare the biomechanical qualities of a bone plug tibial inlay technique with the commonly applied interference screw of patellar tendon PCL grafts. Twenty patellar tendons including a bone block were harvested from ten human cadavers. The grafts were implanted into twenty legs of adult German country pigs. In group P, the grafts were attached in a press-fit technique with accessory bone plug. In group S, the grafts were fixed with an interference screw. Each group consisted of 10 specimens. The constructs were biomechanically analyzed in cyclic loading between 60 and 250 N for 500 cycles recording elongation. Finally, ultimate failure load and failure mode were analyzed. Ultimate failure load was 598.6±36.3 N in group P and 653.7±39.8 N in group S (not significant, P>0.05). Elongation during cyclic loading between the 1st and the 20th cycle was 3.4±0.9 mm for group P and 3.1±1 mm for group S. Between the 20th and the 500th cycle, elongation was 4.2±2.3 mm in group P and 2.5±0.9 mm in group S (not significant, P>0.05). This is the first study investigating the biomechanical properties of tibial press-fit fixation of the patellar tendon with accessory bone plug in posterior cruciate ligament reconstruction. The implant-free tibial inlay technique shows equal biomechanical characteristics compared to an interference screw fixation. Further in vivo studies are desirable to compare the biological behavior and clinical relevance of this fixation device.

Anterior Cruciate Ligament Femoral Socket Drilling With a Retrograde Reamer: Lessons From the Learning Curve

Whereas “anatomic” anterior cruciate ligament reconstruction may improve clinical results, the technique has introduced new technical challenges. The purpose of this technical note and video is to explore tips and tricks that improve femoral socket drilling with a retrograde reamer, bone–patellar tendon–bone graft passage, and interference screw fixation. The techniques for retrograde femoral socket drilling in an inside-out direction, bone–patellar tendon–bone graft passage, and interference screw fixation are described and demonstrated. Pitfalls, troubleshooting tips, and possible solutions are discussed. With the retrograde reamer, the femoral socket can be placed in the footprint of the anterior cruciate ligament with a longer and more vertical tunnel. By modifying the size of the patellar bone plug, graft passage is improved. With care and technique, interference screw fixation in the femoral socket over a guidewire is possible.

Complications Following Subpectoral Biceps Tenodesis with Interference Screw Fixation

Subpectoral biceps tenodesis is considered an effective and increasingly popular method to manage long head of the biceps tendon pathology and combined lesions of the biceps-labral complex. The purpose of this study is to report the complications following this procedure in a large prospective group of patients using a consistent technique.

Effects of Tunnel Dilation and Interference Screw Position on the Biomechanical Properties of Tendon Graft Fixation for Anterior Cruciate Ligament Reconstruction

The purpose of this study was to evaluate the effects of screw position and compaction of the bone tunnel on the strength of the flexor tendon graft after fixation using interference screws. Forty fresh-frozen porcine tibias were used for this study. The digital flexor tendons were folded into a quadrupled graft measuring 9 mm in diameter. In the extraction-drilling group, tibial bone tunnels were drilled with a conventional cannulated 9-mm drill bit in a single step. In the compaction-drilling group, bone tunnels were drilled using a cannulated 7-mm drill bit and were expanded to a final diameter of 9 mm in 0.5-mm increments by placement of dilators with increasing diameter. The grafts were fixed using 9× 30-mm titanium screws in central and eccentric positions. Specimens underwent a cyclic-loading test, and the surviving specimens were then loaded until failure. Graft displacement after 1,500 loading cycles occurred significantly more often in the extraction-drilling group with eccentric screw placement than in the groups of extraction-drilling (P < .05) and compaction-drilling (P < .01) with central screw placement. There were no statistically significant differences for the maximum screw insertion torque, maximum load at failure, or stiffness among the 4 groups. Onestrand of the quadrupled tendon grafts showed partial injury during screw insertion in 3 (30%) and 4 (40%) of 10specimens of the extraction-drilling and compaction-drilling groups with central screw placement, respectively. Central screw placement significantly decreased the displacement of the tendon graft in comparison with eccentric screw placement in the extraction-drilling condition. Compaction of the bone tunnel walls by serial dilation inacentral screw position did not increase the strength of interference screw fixation of a soft tissue graft. When using the extraction method and fixing the graft in an eccentric position, it is advisable to provide additional fixation outside the tunnel to prevent slippage of the graft.

Biomechanical Study Comparing Biceps Wedge Tenodesis With Other Proximal Long Head of the Biceps Tenodesis Techniques

The purpose of this biomechanical study was to compare the ultimate failure strength, stiffness, cyclic displacement, and failure displacement of 5 different proximal biceps tenodesis fixation techniques, specifically comparing wedge tenodesis with the other 4 techniques. Forty cadaveric shoulders underwent 1 of 5 long head of the biceps tenodesis techniques and were cyclically tested to failure by use of tensile forces applied parallel to the longitudinal axis of the humerus. A preload at 5 N was applied for 2 minutes, followed by cyclical loading for 500 cycles from 5 to 70 N at 1 Hz and a pull-to-failure test at 1 mm/s. The techniques studied were wedge tenodesis, suture anchor fixation, suprapectoral interference screw fixation, T-wedge tenodesis, and the percutaneous intra-articular transtendon (PITT) technique. Cyclic displacement, failure displacement, and stiffness were calculated. The wedge tenodesis technique had an ultimate failure load similar to interference screw fixation and a greater ultimate failure load and stiffness than the suture anchor, PITT, and T-wedge techniques (P < .05). In this biomechanical study, wedge tenodesis was found to have an ultimate failure load similar to interference screw fixation and a greater ultimate failure load and stiffness than the suture anchor, PITT, and T-wedge techniques. On biomechanical testing, wedge tenodesis compares favorably with other techniques and may be a useful clinical option for proximal biceps tenodesis.

Tunnel Widening After Anatomic Double-Bundle and Mid-Position Single-Bundle Anterior Cruciate Ligament Reconstruction

The purpose of this study was to compare the amount of postoperative bone tunnel enlargement after anatomic double-bundle (DB) and single-bundle (SB) anterior cruciate ligament (ACL) reconstruction 6 to 8 months after surgery. Twenty-one consecutive patients undergoing anatomic 4-tunnel DB ACL reconstruction and 24 patients undergoing anatomic 2-tunnel SB ACL reconstruction were included in this study. In both groups a hybrid fixation technique with interference screw and extracortical fixation at the tibia and an extracortical fixation technique at the femur were used. Magnetic resonance imaging was performed on the second postoperative day and at a mean of 8 months' follow-up (range, 6.8 to 8.3 months) to assess intraoperative and postoperative bone tunnel enlargement. Tunnel widening was determined in different planes by digitally measuring the diameters of the bone tunnels. Tunnel position was measured and classified according to Harner etal. (femoral) and Stäubli etal. and Petersen etal. (tibial). Magnetic resonance imaging showed that all bone tunnels were anatomically placed within the area of the original ACL insertion zone. Compared with the intraoperative drill diameter, we observed only a slight increase in tunnel diameter in both groups on the second postoperative day. At 8 months postoperatively, significant bone tunnel widening occurred in all bone tunnels (P < .001). However, no significant differences were found between tunnel enlargement in the DB group and tunnel enlargement in the SB group (P > .05), either on the tibial side or on the femoral side. In 2 cases tibial tunnel communication was noted at follow-up. With the use of anatomic SB and DB ACL reconstruction techniques, the results of bone tunnel enlargement were comparable; no significant difference was observed between the tibial and femoral tunnels. Level III, prospective comparative study.

A Prospective Randomized Study Comparing Double- and Single-Bundle Techniques for Anterior Cruciate Ligament Reconstruction

Background: The aim of the study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using either the double-bundle or single-bundle technique with hamstring tendon autografts in an unselected group of patients. Hypothesis: Double-bundle ACL reconstruction will render a better outcome on the pivot-shift test. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A randomized series of 103 patients (33 women, 70 men; median age, 27 years; range, 18-52 years) with a unilateral ACL rupture underwent anatomic ACL reconstruction. The double-bundle technique was used in 53 patients, and the single-bundle technique was used in 50 patients. The ACL footprint was visualized, and the femoral tunnel was drilled through the anteromedial portal; interference screw fixation was used at both ends. The patients were examined preoperatively and at a median of 26 months (range, 22-42 months) after the reconstruction by a blinded observer. The primary variable was the pivot-shift test. Results: At 2-year follow-up, 98 patients (93%) were examined. Clinical assessments at follow-up revealed no significant differences between the double-bundle and single-bundle groups in terms of the pivot-shift test, KT-1000 arthrometer laxity measurements, manual Lachman test, range of motion, Lysholm knee scoring scale, Tegner activity scale, Knee Injury and Osteoarthritis and Outcome Score (KOOS), 1-legged hop test, and square hop test. A significant improvement was seen in both groups compared with the preoperative values in terms of most clinical assessments. Conclusion: In this prospective randomized study, the primary variable, the pivot-shift test, and other subjective and objective outcome variables revealed no significant differences between the double-bundle and single-bundle techniques at 2 years after ACL reconstruction in an unselected group of patients.

Pre-tibial reaction to biointerference screw in anterior cruciate ligament reconstruction

BackgroundWe aim to report a series of cases that presented as pre-tibial swelling and pain following anterior cruciate ligament (ACL) reconstruction using bioabsorbable fixation devices. MethodsAll ACL reconstructions done between 2007 and 2010 were reviewed retrospectively to identify complications related to bioabsorbable fixation devices. We performed 273 ACL reconstructions over a period of three years from 2007 to 2010 using a bioabsorbable screw for tibial fixation of the quadrupled hamstring autograft. ResultsFourteen patients (5%) at mean age of 30 (range 16–47) years, presented to us at a mean post-operative period of 26months (range 12–39) with pre-tibial pain and swelling over the tibial screw site. All of them had normal inflammatory markers. All of these patients underwent surgical debridement, which revealed remnants of screw and reactive material. There was no evidence of infection in the intra-operative specimen cultures. Histopathology revealed a reactive appearance and surrounding myxoid changes. Removal of screw debris and curettage of the tunnel resulted in complete recovery of all patients at a mean follow up of 12 (range 8–16) months. ConclusionsPre-tibial cyst along with other adverse biological response should be considered as a possible complication in ACL reconstruction. We report an incidence of 5% of pre-tibial reaction in patients undergoing ACL reconstruction with bio-absorbable interference screw fixation for the proximal tibia.

Impact of tendon suturing on the interference fixation strength of quadrupled hamstring tendon grafts

Interference screw fixation of soft tissue grafts has been a widely used fixation technique for cruciate ligament reconstruction. Suturing of the graft construct prior to graft fixation has been proposed to increase fixation strength; however, the effect on mechanical properties has not been well characterized. The goal of this study was to determine whether uniform suturing of the tendon graft affects (1) ultimate fixation strength of the hamstring tendon graft and (2) motion of the tendon in the bone tunnel during cyclic loading when comparing sutured grafts vs. unsutured grafts. Eight pairs of matched mature porcine tibias (age <2years) and eight paired fresh-frozen human quadrupled hamstring tendon grafts were used. One quadrupled graft from each pair was placed into one of two groups. In the group A a single cerclage suture 3cm from the doubled end of the graft was placed to join the four tendon strands. In group B a heavy suture was used to tightly unite the four strands of tendon graft to provide a better grip for the interference screw during fixation. The grafts were placed in tibial bone tunnels that matched the graft's diameter and fixed with an interference screw. The looped end of the graft and the attached tibia were rigidly fixed in a material testing machine. The graft constructs were subjected to 100 cycles of 20-250N load, followed by a load-to-failure test. In addition, a motion analysis system was used during cyclic testing to better determine the amount of elongation at the graft-tunnel interface. Statistical analysis of the failure load and stiffness and the overall elongation following cyclical loading was performed using the Wilcoxon rank sum test. Level of significance was set at p<0.05. Elongation at the tendon-bone interface during sub-maximal cyclic loading was 2.4±1.4mm (unsutured) vs. 2.0±0.7mm (sutured) (p>0.05). Failure load of the grafts without sutures (634±86N) was significantly lower than with the sutures (837±183N). Ultimate stiffness of group A (283±34N/mm) was lower than that of group B (331±51N/mm); however, this was not statistically significant (p=0.051). This study confirms that suturing of the graft construct before interference screw fixation may increase ultimate failure load. However, an improvement of structural properties in response to cyclic loading with sub-maximal loads could not be confirmed. Clinicians using interference screw fixation may suture the graft to improve fixation strength; however, suturing does not appear to allow a more aggressive rehabilitation after surgery.

Biomechanical properties of femoral posterior cruciate ligament fixations

The success of reconstructions of the posterior cruciate ligament (PCL) mainly depends on the fixation strength of the tendon-bone interface. Reliable data about the mechanical characteristics of PCL fixation techniques are sparse. The aim of this study was to investigate the biomechanical properties of different femoral PCL fixation techniques. Fresh human cadaver quadriceps (Q) and hamstring (H) tendons were harvested and fixed into porcine femora with a press-fit fixation suturing the tendon over a bone bridge (group A), a novel implant post-fixation (group B) or an interference screw fixation (group C). Each group consisted of 10 specimens. The constructs were cyclically stretched and eventually loaded until failure. Elongation during cyclic loading, stiffness, failure mode and maximum failure load was evaluated. Elongation during cyclical loading was significantly larger between the 1st and the 20th cycle than between the 20th and the 500th cycle in all groups (p<0.05). Maximum failure load was 409±71 (336-517) N in group QA, 456±58 (347-510) N in group QB, 548±116 (400-798) N in group QC, 472±114N (316-676N) in group HA, 494±98N(371-668N) in group HB and 498±87N (391-687N) in group HC (significantly higher for QB compared to QA, p<0.05). This is the first study investigating the biomechanical properties of femoral PCL fixations. Implant-free fixation techniques like press-fit or post-fixations are able to withstand equal biomechanical forces compared to interference screw fixation. The novel fixations described in this study can be considered as a reliable alternative for the reconstruction of PCL using either hamstring or quadriceps tendons.

Graft failure versus graft fixation in ACL reconstruction: histological and immunohistochemical studies in rabbits

The causes of graft failure after anterior cruciate ligament (ACL) reconstruction are multifactorial including the methods of graft fixation. The purpose of this study was to examine the ACL graft failure in three different methods of graft fixations including interference screw fixation, suture-post fixation and combined interference screw and suture-post fixation. We hypothesized that the fixation method after ACL reconstruction can affect the graft healing in tibial tunnel. Eighteen New Zealand white rabbits were categorized into three groups according to the method of fixation in unilateral ACL reconstruction with long digital extensor autograft. Histological examination demonstrated that the combined fixation and suture-post fixation groups showed significantly better integration between tendon and bone (P=0.04). In immunohistochemical analysis, the combined fixation and suture-post fixation groups showed significantly higher BMP-2 and VEGF expressions than interference screw (P<0.01). The tendon-bone healing after ACL reconstruction was affected by the method of graft fixation. Combined fixation with interference screw and suture-post reduced graft-tunnel micromotion and improved the graft healing in tibial tunnel.

Scapholunate Ligament Reconstruction

Background Scapholunate reconstruction poses a challenge to orthopedic surgeons. Materials and Methods Prospective cohort. Description of Technique Our technique for scapholunate (SL) reconstruction involves ligament reconstruction utilizing a portion of the flexor carpi radialis tendon rerouted via transosseous tunnels across the scaphoid, lunate, and triquetrum (scapholunotriquetral tenodesis). The tendon graft is secured with interference screw fixation into the triquetrum. The philosophy of this new technique is to reduce subluxation and maintain the relationship between scaphoid and lunate by placing a graft through the center of the SL articulation. This graft is then tensioned by passing it centrally through the lunate and triquetrum and secured using an interference screw in the triquetrum. Secondary stabilizers, including the dorsal intercarpal ligament, are then augmented by passing the graft back to the scaphoid, crossing from the triquetrum over the proximal capitate. This further reinforces the translational relationship between the scaphoid and the triquetrum and, therefore, augments stability of the SL articulation. Results We have utilized this technique successfully in over 40 patients since 2009. We report on a prospective consecutive series of 11 patients with over 12 months follow-up (range 12 to 24 months) demonstrating good early radiological and clinical outcomes. Conclusions In developing this technique, we aimed to take the best features of previously described techniques and address the perceived shortcomings of each. We believe there are several benefits of our technique. Moreover, few other techniques address as many of the aspects of chronic SL instability as our technique does.

A review of anterior cruciate ligament injuries and reconstructive techniques. Part 2: Treatment

The aims of treatment of anterior cruciate ligament rupture are to eliminate pain, restore stability and allow early return to activity while preventing early degeneration. Ruptures can be treated conservatively, which requires careful patient selection and avoidance of high-risk activity. Each patient must be treated on an individual basis with consideration given to the level of activity, desire to return to sport, donor site morbidity and compliance with post-operative regimes. Through the evolution of single incision, arthroscopic anatomic reconstruction, our knowledge of the native anterior cruciate ligament anatomy and knee kinematics has progressed. The current gold standard uses four-stranded hamstring autograft with endobutton and interference screw fixation. Double-bundle reconstruction is technically challenging with greater risk and best reserved for larger knees with larger native ligaments. Although treatment has advanced considerably over the years, there are still a number of contentious issues which are considered in this review. Part two of this review discusses the short- and long-term objectives of surgery, the indications and timing of surgery, different graft materials, tunnel positions and rehabilitation programmes. We also evaluate the role of anatomical reconstruction and single- versus double-bundle anterior cruciate ligament reconstructions.