Screw fixation is an established method for anterior cruciate ligament (ACL) reconstruction, although with a high rate of implant-related complications. An allograft system for implant fixation in ACL reconstruction, the Shark Screw ACL (surgebright GmbH) could overcome some of the shortcomings of bioabsorbable screws, such as foreign body reaction, need for implant removal and imaging artefacts. However, it needs to provide sufficient mechanical stability. Therefore, the aim of this study was to investigate the biomechanical stability, especially graft slippage, of the novel allograft system versus a conventional bioabsorbable interference screw (BioComposite Interference Screw; Arthrex Inc.) for tibial implant fixation in ACL reconstruction. Twenty-four paired human proximal tibiae (3 female, 9 male, 72.7 ± 5.6 years) underwent ACL reconstruction. The quadrupled semitendinosus and gracilis tendon graft were fixed in one specimen of each pair using the allograft fixation system Shak Screw ACL and the contralateral one using an interference screw. All specimens were cyclically loaded at 1 Hz with peak load levels monotonically increased from 50 N at a rate of 0.1 N/cycle until catastrophic failure. Relative movements of the graft versus the tibia were captured with a stereographic optical motion tracking system (Aramis SRX; GOM GmbH). The two fixation methods did not demonstrate any statistical difference in ultimate load at graft slippage (p = 0.24) or estimated survival at slippage (p = 0.06). Both, the ultimate load and estimated survival until failure were higher in the interference screw (p = 0.04, and p = 0.018, respectively). Graft displacement at ultimate load reached values of up to 7.2 mm (interference screw) and 11.3 mm (Shark Screw ACL). The allograft screw for implant fixation in ACL reconstruction showed similar behavior in terms of graft slippage compared to the conventional metal interference screw but underperformed in terms of ultimate load. However, the ultimate load may not be considered a direct indicator of clinical failure

Meniscal root tears can result from traumatic injury to the knee or gradual degeneration. When the root is injured, the meniscus becomes de-functioned, resulting in abnormal distribution of hoop stresses, extrusion of the meniscus, and altered knee kinematics. If left untreated, this can cause articular cartilage damage and rapid progression of osteoarthritis. Multiple repair strategies have been described; however, no best fixation practice has been established. To our knowledge, no study has compared suture button, interference screw, and HEALICOIL KNOTLESS fixation techniques for meniscal root repairs. The goal of this study is to understand the biomechanical properties of these fixation techniques and distinguish any advantages of certain techniques over others. Knowledge of fixation robustness will aid in surgical decision making, potentially reducing failure rates, and improving clinical outcomes. 19 fresh porcine tibias with intact medial menisci were randomly assigned to four groups: 1) native posterior medial meniscus root (PMMR) (n = 7), 2) suture button (n = 4), 3) interference screw (n = 4), or 4) HEALICOIL KNOTLESS (n = 4). In 12 specimens, the PMMR was severed and then refixed by the specified group technique. The remaining seven specimens were left intact. All specimens underwent cyclic loading followed by load-to-failure testing. Elongation rate; displacement after 100, 500, and 1000 cycles; stiffness; and maximum load were recorded. Repaired specimens had greater elongation rates and displacements after 100, 500, and 1000 cycles than native PMMR specimens (p 0.05). The native PMMR showed greater maximum load than all repair techniques (p 0.05). In interference screw and HEALICOIL KNOTLESS specimens, failure occurred as the suture was displaced from the fixation and tension was gradually lost. In suture button specimens, the suture was either displaced or completely separated from the button. In some cases, tear formation and partial failure also occurred at the meniscus luggage tag knot. Native PMMR specimens failed through meniscus or meniscus root tearing. All fixation techniques showed similar biomechanical properties and performed inferiorly to the native PMMR. Evidence against significant differences between fixation techniques suggests that the HEALICOIL KNOTLESS technique may present an additional option for fixation in meniscal root repairs. While preliminary in vitro evidence suggests similarities between fixation techniques, further research is required to determine if clinical outcomes differ

The purpose of this study was to quantify tibial tunnel enlargement at 3-, 6- and 12-months post-anterior cruciate ligament reconstruction (ACLR), and evaluate the magnitude of tunnel widening with use of a Poly (L-lactic Acid) interference screw (PLLA (Bioscrew XtraLok, Conmed, New York)) compared to a Poly (L-lactic Acid) + tricalcium phosphate interference screw (PLLA+TCP (GENESYS Matryx screw comprised of microTCP and 96L/4D PLA, Conmed, New York)). This was a prospective randomized controlled trial with two parallel groups. Eighty unilateral ACL-deficient participants awaiting ACLR surgery were recruited between 2013 and 2017 from the clinic of a sole fellowship trained orthopaedic surgeon. Patients had to be skeletally mature and less than 45 years old, with no concomitant knee ligament injuries requiring surgery, chondromalacia, or previous history of ipsilateral knee joint pathology, surgery or trauma to the knee. Participants were randomized intra-operatively into either the PLLA or PLLA+TCP tibial interference screw fixation group. Study time points were pre-, 3-, 6-, and 12-months post ACLR. Participants underwent x-rays with a 25 mm calibration ball, IKDC knee assessment, and completed the ACL-Quality of Life score (ACL-QOL) at each visit. Measurement (mm) of the most proximal and distal extents as well as the widest point of the tibial tunnel were taken using efilm (IBM Watson Health) and were standardized relative to the calibration ball. A contrast inverter was used to determine clear borders based on contrast between normal and drilled bone. In addition, a subjective evaluation of the tunnel was conducted looking for bowing of the borders of the tunnel or change in tunnel shape, categorizing the tunnel as widened or not widened. Differences between groups at each time point were evaluated using independent t-tests corrected for multiple comparisons. Tunnel width was also compared as a percentage of actual screw size at 12-months post-operative. Categorical data were compared using Fisher's Exact Test. Forty participants were randomized to each group with mean age (SD) of 29.7 (7.6) and 29.8 (9.1), for PLLA and PLLA+TCP, respectively. There were no differences between groups in age, gender or ACL-QOL. There were no differences found between groups at any time point in either tunnel width measurements or tunnel width as a percentage of actual screw size. The greatest difference between groups was noted in the measurement of the widest point on lateral x-ray view with a mean difference of 11%. Based on subjective evaluation of tunnel shape, three participants had visible widening in the PLLA group, and two in the PLLA+TCP group (p=NS). No differences in tunnel widening were identified between ACL reconstruction patients using a PLLA interference screw compared to a PLLA+TCP screw for tibial fixation up to 12-months post-operative

The purpose of this study is to identify the optimal amount of knee flexion required to drill the femoral tunnel in ACL reconstruction using the transtibial technique in order to ensure the correct alignment between the femoral tunnel and the interference screw. Methods: Twenty (10 × 2) fresh-frozen cadaveric knees were used. The native ACL was resected and its tibial attachment was identified. The angle of the tibial tunnel was set at 55° using an Arthrex tibial guide. The extra-articular tibial tunnel entry point was located at the anterior border of the superficial MCL. The intra-articular exit point of the guide wire was digitized with a digital camera and referenced to anatomical landmarks (the anterior border of the PCL, the lateral aspect of the medial spine and the anterior horn of the lateral meniscus). The femoral tunnels were made using the transtibial technique and a 5mm femoral guide to insert guidewires at 70, 80, and 90 degrees of knee flexion (groups a, b, c respectively). The angles of divergence between the longitudinal axis of the femoral tunnel and the interference screw (placed through an anteromedial portal at 120° of knee flexion) were then measured. Results: The degrees of divergence were: 5° ± 2° for group a, 12° ± 4 for group b, and 15° ± 3° for group c. Conclusions: Optimal femoral tunnel and interference screw alignment is achieved using the transtibial technique when the femoral tunnel is drilled with the knee in 70 degrees of flexion and the screw is inserted at 120 degrees of knee flexion. This study identifies a mathematical formula for the optimal amount of knee flexion required to drill the femoral tunnel in ACL reconstruction using the transtibial technique in order to ensure the correct alignement between the femoral tunnel and the interference screw

Introduction Concentric interference screw placement has been proposed as having potentially better biological graft integration than eccentric interference screw placement during soft tissue ACL reconstruction. The purpose of this study was to determine whether a wedge shaped concentric screw was at least equivalent to an eccentric screw in stiffness, yield load, ultimate load and mode of failure. Methods Seven matched pairs of human cadaveric tendon in porcine tibia with titanium wedge shaped screws were randomly allocated to either the eccentric or concentric groups. Bone tunnels were drilled 45° to the long axis of the tibia, akin to standard ACL reconstruction. Tendon diameter was matched to tunnel diameter and a screw one millimetre larger than tunnel diameter was inserted. An Instrom machine was used to pull in the line of the tendon. Tendons were inspected after construct disassembly. Results The concentric screw configuration showed significantly higher stiffness (p< 0.0085), yield load (p< 0.0135) and ultimate load (p< 0.0075). The mode of failure in the eccentric screw position was slippage at the screw tendon interface in all cases. In the concentric group 88% of cases had a breakage in the tendon and 13% of cases had slippage at the tendon bone interface. However, it was observed during construct disassembly that there was more macroscopic damage to the tendon substance in the concentric group. Failure was mostly by tendon breakage, which reflects the strongest fixation possible with the tendon being the weakest link in the system. Conclusions Concentric interference screw fixation of soft tissue graft offers superior fixation in single pullout mode when compared to eccentric interference screw fixation

This study aims to compare the biomechanical properties of the “Double Lasso-Loop” suture anchor (DLSA) technique with the commonly performed interference screw (IS) technique in an ex vivo ovine model. Fourteen fresh sheep shoulder specimens were used in this study. Dissection was performed leaving only the biceps muscle attached to the humerus and proximal radius before sharply incised to simulate long head of biceps tendon (LHBT) tear. Repair of the LHBT tear was performed on all specimens using either DSLA or IS technique. Cyclical loading of 500 cycles followed by load to failure was performed on all specimens. Tendon displacement due to the cyclical loading at every 100 cycles as well as the maximum load at failure were recorded and analysed. Stiffness was also calculated from the load displacement graph during load to failure testing. No statistically significant difference in tendon displacement was observed from 200 to 500 cycles. Statistically significant higher stiffness was observed in IS when compared with DSLA (P = .005). Similarly, IS demonstrated significantly higher ultimate failure load as compared with DSLA (P = .001). Modes of failure observed for DSLA was mostly due to suture failure (7/8) and anchor pull-out (1/8) while IS resulted in mostly LHBT (4/6) or biceps (2/6) tears. DSLA failure load were compared with previous studies and similar results were noted. After cyclical loading, tendon displacement in DLSA technique was not significantly different from IS technique. Despite the higher failure loads associated with IS techniques in the present study, absolute peak load characteristics of DLSA were similar to previous studies. Hence, DLSA technique can be considered as a suitable alternative to IS fixation for biceps tenodesis

Purpose. To evaluate the results of quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with four fold Hamstring Tendon Graft using Transfix and Bioabsorbable Interference Screw Fixation. Study Design. Retrospective review. Methods. Sixty-five patients (66 knees) were retrospectively identified by chart review as having undergone quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction, with four fold Hamstring Tendon Graft, using Transfix and Bioabsorbable Interference Screw Fixation. All patients underwent a minimum two-year follow-up. Results. Data were collected on 48 knees in 47 patients (73%) at an average 30.2 months (range 24 to 43) after surgery. Thirty-six patients (37 knees) returned for clinical evaluation (56% return) and subjective follow-up only was obtained in 11 patients (17%). The mean Lysolm knee score was 91 (range, 45 to 98), with a mean of 97 for the uninvolved knee. The mean Tegner activity score was 5.7 (range 3 to 7). The KT-1000 arthrometer mean side-to-side difference for manual maximum displacement was 2.03 mm (range -1 to 8). The mean International Knee Documentation Committee knee score was 83 (range 47 to 100). Patients who underwent associated partial meniscectomy or meniscal repair had significantly lower International Knee Documentation Committee scores than patients without associated procedures (P < 0.01). Conclusions. Quadrupled hamstring tendon autograft anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation is comparable with other methods of anterior cruciate ligament reconstruction in terms of patient satisfaction, knee stability, and function

Aim: To determine if a side-to-side difference in laxity occurs with anterior cruciate ligament (ACL) reconstruction utilizing a hamstring tendon and standard RCI (Smith and Nephew) interference screw fixation, and if this can be affected by the use of a reverse thread RCI screw in right-sided knees. Methods: This was a prospective study of 80 patients undergoing right-sided ACL reconstruction with hamstring tendon autograft. Females were excluded in case of there being a sex difference in postoperative laxity with HT graft. The study group comprised of 36 males utilising standard RCI screws (STD) and 44 males utilising reverse-thread RCI screws (REV). The same technique was used on all patients and all procedures were carried out by the same surgeon. The patients were evaluated at six and 12 months following the surgery with KT1000, IKDC assessment, and Lysholm Knee Score. Results: At the follow-up after 12 months, the average side-to-side differences using KT1000 testing were 2.0 mm (STD) and 1.0 mm (REV) using manual maximum, and 1.7 (STD) and 1.0 (REV) using KT20. Both results were statistically significant. In addition, 33% of the STD group had a manual maximum of ≥3mm compared with 11% of the REV group (p< 0.01). Accordingly, there was a higher incidence of grade I instability (Lachman) in the STD group (23% of STD group; 8% of REV group, p=0.04). Conclusion: The use of a reverse-thread interference (RCI) screw for femoral fixation in right-sided hamstring tendon ACL reconstructions in males significantly decreased side-to-side laxity at the 12 month review when compared with standard RCI fixation

A new technique of trapeziometacarpal suspension arthroplasty is described. Suspension arthroplasty as a treatment for trape-ziometacarpal arthritis has been studied extensively in the literature, but only using relatively weak forms of tendon-bone fixation. Interference screw fixation for tendon grafts has been proven in other areas of the body such as the knee and shoulder. Our technique involves trapeziectomy and suspension arthroplasty using one half of the flexor carpi radialis tendon, left attached distally. A short segment (approximately 2 cm) is harvested and passed through a 4 mm drill hole in the proximal thumb metacarpal. This is accurately positioned using an initial K-wire and then a cannulated drill. Fixation is achieved with a 4 mm Bio-tenodesis screw (Arthrex) and enhanced using a 4/0 Fibrewire (Arthrex) Krackow suture weave. Due to the strength of fixation, no supplemental fixation is required and immobilisation is only used in the initial postoperative period. There is no need for additional support in the form of tendon interposition. Although these are preliminary results, this technique shows promise for an improvement in outcome for the surgical treatment of thumb carpometacarpal arthritis, compared to current methods

Our study aims to demonstrate the efficacy of using endobutton and interference screw technique in the repair of acute distal biceps ruptures. From April 2009 to May 2013, 25 consecutive patients had acute distal biceps tendon repairs using an endobutton and interference screw technique. 3 patients were lost to follow up leaving 22 patients available for review. Mean follow up was 24 months(1–51). All were evaluated using a questionnaire, examination, radiographs, power measurements, and Oxford Elbow and MAYO scores. Overall 95% patients (21/22) felt that their surgery was successful and rated their overall experience as excellent or good. Mean return to work was at 100 days(0–280) and mean postoperative pain relief was 23 days(1–56). 55% returned to sport at their pre-injury level. There was one case (4.5%) of heterotopic calcification with 3 superficial infections(14%). There were no intra or postoperative radial fractures, metalwork failures or metalwork soft tissue irritations. Mean pre-operative Oxford Elbow Scores were 18(6–37) and post operative 43(24–48) (p<0.00001). Mean pre-operative Mayo scores were 48(5–95) and post-operative were 95(80–100)(p<0.00001). Our study supports that distal biceps repairs using the endobutton and interference screw technique appears to lead to high patient satisfaction rates with a relatively early return to function

Our study aims to demonstrate the efficacy of using endobutton and interference screw technique in the repair of acute distal biceps ruptures. From April 2009 to May 2013, 25 consecutive patients had acute distal biceps tendon repairs using an endobutton and interference screw technique. 3 patients were lost to follow up leaving 22 patients for review. Mean follow up was 24 months (1–51). All were evaluated using a questionnaire, examination, radiographs, power measurements, and Oxford Elbow (OES) and MAYO scores. Overall 95% patients (21/22) felt that their surgery was successful and rated their experience as excellent or good. Mean return to work was 100 days (0–280) and mean postoperative pain relief was 23 days (1–56). 55% returned to sport at their pre-injury level. There was one case (4.5%) of heterotopic calcification with 3 superficial infections (14%). There were no intra or postoperative radial fractures, metalwork failures or metalwork soft tissue irritations. Mean pre-operative OES were 18 (6–37) and post operative 43 (24–48) (p < 0.01). Mean pre-operative Mayo scores were 48 (5–95) and post-operative 95 (80–100) (p < 0.01). Our study supports that distal biceps repairs' with endobutton and interference screw technique appears to lead to high patient satisfaction rates with a relatively early return to function

Single-strand medial collateral elbow ligament (MCL) reconstruction strength was evaluated using double docking (DD) and interference screw (IS) methods with either palmaris longus (PL) or Graft Jacket_ (GJ) as the reconstruction material. Thirteen upper-extremities were mounted in 90° valgus orientations, and subjected to increasing cyclic valgus loading until failure. DD reconstructions outperformed IS reconstructions (P< 0.05), while PL and GJ performed comparably (P> 0.05). The initial Graft Jacket strength makes it a potential alternative to palmaris longus tendons; Laboratory evaluation of graft strength during healing is required. For its simplicity and strength, the DD technique should be considered, clinically. Single-strand medial collateral elbow ligament (MCL) reconstruction strength was evaluated using double docking (DD) and interference screw (IS) methods with either palmaris longus (PL) or Graft Jacket_ (GJ) as the reconstruction material. Thirteen, fresh-frozen upper-extremities (66 ±5 years) were cleaned of all soft tissues except the medial and lateral collateral ligaments, flexed to 90° and mounted in a rigid, valgus testing system. DD or IS reconstructions were performed using either PL or GJ. A cyclic (0.5Hz) load was applied 12cm distal to the medial epicondyle. After 500 cycles, the load was increased by 10N until catastrophic failure or a length increase of 10mm. The mean maximum load for the DD with GJ was 65 ±12N; for the IS with GJ: 45 ±5N; for the DD with PL: 59 ±11N; and for the IS with PL: 56 ±14N. The mean maximum number of cycles endured by the DD with GJ was 1292 ±562; for the IS with GJ: 356 ±292; for the DD with PL: 1104 ±479; and for the IS with PL: 924 ±690. For both the maximum load and number of cycles, the DD outperformed the IS (P< 0.05) and the GJ and PL performed comparably (P> 0.05). Single-strand reconstructions using the double dock method outperform the interference screw technique. For its simplicity and strength, the DD technique should be considered, clinically. The initial Graft Jacket strength makes it a potential alternative to palmaris longus tendons; laboratory evaluation of graft strength during healing is required. Funding: This study was partially funded by Wright Medical Technology (Arlington, TN) and the Canadian Institute for Health Research. Please contact author for graphs and/or diagrams

The purpose of this study was to describe our experience of the Calaxo Osteoconductive interference screw (Smith & Nephew) when used for both femoral and tibial graft fixation in Double Bundle ACL reconstruction. Since May 2006, all patients with an ACL deficient knee were reconstructed using the Double Bundle technique. All were followed prospectively and outcome data collected. Evidence of fixation failure was established subjectively by clinical examination (Lachman, Anterior Draw, Pivot Shift) and objectively via KT-1000 arthrometer. Following ethical approval, post-operative CT scans (immediate and 1 year) were performed on our first 10 patients allowing assessment of tunnel dimensions/fill. Thirty two patients (29 male, 3 female) with a mean age of 30 (range 18-46) were included. At last follow-up, no evidence of graft/fixation failure was found; KT-1000 mean side-side difference 1.4mm (range −3 to +6). All patients had a positive pivot shift preoperatively which was abolished postoperatively. One patient had a postoperative infection with no other complications reported. Radiologically the screws did not show complete resorption but areas of new bone were identified. We have shown satisfactory results with use of the Calaxo screw when used in Double Bundle Reconstruction. We have not had any cases of the adverse local soft tissue reaction, which has led to this screw being withdrawn from clinical use. Even when using a total of four screws in each knee. A previous study published by Seibold (2007) has shown tunnel widening and communication when suspensory fixation is used in Double Bundle reconstruction. This has the potential risk of leading to fracture between the tunnels. This has not been seen with the Calaxo screw which may be a result of the biological action of the screw which should ultimately lead to a reduction in these risks

A paper was presented two years ago reviewing evidence of absorption of the Bio Interference screw and tunnel widening at three, six and 12 months following anterior cruciate ligament reconstruction using double-stranded hamstrings. The femoral fixation was with an Endobutton with a double loop of Mercylene tape with a Bio Interference screw and an extra small staple for the distal fixation. This paper presents further magnet resonance imaging (MRI) studies at least two years after surgery on 10 of those patients to assess if there was any MRI evidence of absorption of the Bio Interference screw or tunnel widening (in particular ganglion formation) in the femoral or tibial tunnels. The results showed that at least two years after surgery there was little evidence of Bio Interference screw absorption. There was no evidence of tunnel widening

Introduction: The purpose of this study was to describe our experience of the Calaxo Osteoconductive interference screw (Smith & Nephew) when used for both femoral and tibial graft fixation in Double Bundle ACL reconstruction. Methods: Since May 2006, all patients with an ACL deficient knee were reconstructed using the Double Bundle technique. All were followed prospectively and outcome data collected. Evidence of fixation failure was established subjectively by clinical examination (Lachman, Anterior Draw, Pivot Shift) and objectively via KT-1000 arthrometer. Following ethical approval, post-operative CT scans (immediate and 1 year) were performed on our first 10 patients allowing assessment of tunnel dimensions/fill. Results: Thirty two patients (29 male, 3 female) with a mean age of 30 (range 18–46) were included. At last follow-up, no evidence of graft/fixation failure was found; KT-1000 mean side-side difference 1.4mm (range −3 to +6). All patients had a positive pivot shift preoperatively which was abolished postoperatively. One patient had a postoperative infection with no other complications reported. Radiologically the screws did not show complete resorption but areas of new bone were identified. Discussion: We have shown satisfactory results with use of the Calaxo screw when used in Double Bundle Reconstruction. We have not had any cases of the adverse local soft tissue reaction, which has led to this screw being withdrawn from clinical use. Even when using a total of four screws in each knee. A previous study published by Seibold (2007) has shown tunnel widening and communication when suspensory fixation is used in Double Bundle reconstruction. This has the potential risk of leading to fracture between the tunnels. This has not been seen with the Calaxo screw which may be a result of the biological action of the screw which should ultimately lead to a reduction in these risks

Introduction: The use of bioabsorbable devices in sports medicine surgery in the shoulder and knee continues to evolve as new designs, devices and materials become available. Concerns over potential problems associated with metal artifacts and permanent metal devices continue to motivate the development and use of polymeric based devices. Calaxo interference screws (Smith & Nephew Endoscopy, Andover, MA) are composed of a novel bioabsorbable material blend of poly DL- lactide – co – glycolide 85:15 (65%) and calcium carbonate (35%). These screws have been shown to be osteoconductive when placed in the centre of a 4 stranded tendon graft in an ovine ACL reconstruction [1]. The screws are fully resorbed at 26 weeks with new bone formation in the tunnel. In general, osteoconductive materials are often more effective when placed adjacent to a bony bed. This study investigated whether positioning the Calaxo screw adjacent to the bone tunnel was superior to screw placement within the tendon as in our previous study [1]. Materials and Methods: An intra-articular anterior cruciate ligament (ACL) reconstruction model using 2 doubled over tendon autografts whip stitched and inserted into the right hind limb of 8 sheep were used. Animals were culled at 26 or 52 weeks following surgery (n=4 per time point) and data was compared using the same surgical model but with screws placed in the center of the 4 stranded graft (Walsh et al., 2006). The tibias were CT scanned and processed for paraffin histology along the axis of the bone tunnel. Three dimensional models using the DICOM data obtained from the CT where made using MIMICS (Materialise, Belgium). Result & Discussion: Results showed excellent biocompatibility of the screws with no adverse reactions at 26 and 52 weeks as in our previous study [1]. The screws were fully resorbed by 26 weeks with new bone replacing the PLC material. Similarly, the screws were not detectable at 52 weeks with new bone formation where the screw had previously resided. The intra-articular portion of the graft, articular cartilage and synovium was normal at 26 and 52 weeks as previously reported [1]. Tendon – bone healing proximal to the screw progressed in a normal fashion. No calcification of the intraarticular portion of the graft was noted. Computed tomography, 3D models and histology revealed an osteoconductive response to the PLC material with new bone formation as the material degraded in vivo. Placement of the screw adjacent to the tendon graft and thus against the bone tunnel appears to provide superior results compared to screw placement in the middle of the graft sleeve device. This effect may be due to direct contact of the osteoconductive material to the adjacent bone bed. [1] Walsh et al., Arthroscopy 2006, in press

The results of PLLA screws for ACL reconstruction have demonstrated no significant clinical differences when compared to metallic screws up to two years. However, studies examining PLLA-HA screws are lacking, as are medium term outcomes of bioresorbable screws. This study aims to compare the clinical outcome of ACL reconstruction with a PLLA-HA to a titanium screw, and to assess the extent of resorption of the PLLA-HA screw at two and five years after ACL reconstruction. Forty patients were randomised to receive either a PLLA-HA or titanium RCI interference screw for ACL reconstruction. Both examiners and patients were blinded to screw type. Patients were prospectively reviewed at 24 and 60 months after surgery with full IKDC assessment, Instrumented Ligament Testing, Lysholm knee score. MRI scans were performed at two and five years following surgery. Five years after surgery, one patient with a titanium screw had an ACL graft rupture and had undergone revision surgery. Of the remaining 39 patients, 38 (97%) were reviewed at five years. There was no significant difference between the two groups in the volume of the tibial (p=0.89) or femoral (p=0.22) tunnels at five years. Significant screw resorbtion at five years was seen in 77% on the tibial side and 88% on the femoral side in the PLLA group. Good ossification was evident on five year MRI in 94% of the tibial screws and 56% of the femoral screws. In the PLLA-HA group peri tunnel bone marrow oedema was present in 35% of patients on the tibial side and 53% of patients on the femoral side at five years. There was no peri-tunnel bone marrow oedema evident in the titanium group. Peri-graft ganglion cyst was evident on MRI scan on the tibial side in 24% of patients from the PLLA-HA group and 18% of the titanium group (p=0.67). There was no significant difference between the PLLA-HA group and the titanium group on any of the other clinical parameters including IKDC subjective knee score (mean 93), symptoms, range of motion, instrumented ligament laxity (mean 1.8 mm) or overall IKDC grade (90% normal or nearly normal). ACL reconstruction with PLLA-HA bioabsorbable screws affords comparable clinical and subjective results to titanium screws at five years after surgery. Significant progression of PLLA HA screw resorption occurs between two and five years, with over 75% of screws demonstrating some resorption by five years. However, complete resorption was only evident in a small number of patients. ACL reconstruction with a PLLA HA screw has excellent clinical outcomes and progressive screw resorption and ossification is evident at five years

The purpose of this paper is to investigate the relative contribution of each component in the ultimate strength and stiffness of the Evolgate (Citieffe), which is presently a widely used fixation device in DGST ACL reconstruction. The three components of the Evolgate were tested using fresh frozen animal tissue stored at −20° Celsius. Common extensor tendons were harvested from 20-month-old bovine forelimbs. Twenty-four tests were performed for each of the following configurations: six tests using Evolgate complete, six tests using screw alone, six tests using screw and washer and six tests using screw and coil. A randomised t-test was used; differences were considered significant when p< 0.05. The mean strength was: Evolgate complete 1314±194N; coil and screw 700±152N; screw alone 408±86N; and screw and washer 333±93N. There was a significant difference between fixation strength of Evolgate and the other devices, none between screw alone and screw and washer. The mean slippage of the Evolgate was significantly lower than the other devices. The mean stiffness of the Evolgate (269±14 N/mm) was significantly greater than the other devices. On the basis of the results of the present study, the coil appears to be the most important component of the Evolgate, resulting in a significant increase of the fixation strength of the screw. However, it is important to note that, as the washer alone does not improve the strength of the screw, if a washer is associated with a coil a further significant increase in strength and stiffness of the device is observed.

The optimal method of tibial fixation when using a hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction is unclear. This study aimed to compare the risk of revision ACL reconstruction between suspensory and interference devices on the tibial side. Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. Only patients with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. The rate of revision ACL reconstruction was compared between suspensory and interference devices on the tibial side. Univariate Chi-Square test and multivariate Cox regression was performed to compute hazard ratios (HR) and 95% confidence intervals (CI) with adjustment for age, gender, time-to-surgery, activity at the time of injury, number of graft strands and graft diameter. 6145 cases were analyzed, of which 59.6% were fixed with a suspensory device on the tibial side (n = 3662), 17.6% fixed with an interference screw with a sheath (n = 1079) and 22.8% fixed with an interference screw without a sheath (n = 1404). When compared to suspensory devices (revision rate = 3.4%), a higher risk of revision was observed when using an interference screw with a sheath (revision rate = 6.2%, adjusted HR = 2.05, 95% CI 1.20 – 3.52, p = 0.009) and without a sheath (revision rate = 4.6%, adjusted HR = 1.81, 95% CI 1.02 – 3.23, p = 0.044). The number of graft strands and a graft diameter of ≥8 mm did not influence the risk of revision. When reconstructing the ACL with a hamstring tendon autograft, the use of an interference screw, with or without a sheath, on the tibial side has a higher risk of revision when compared to a suspensory device

Bone-patellar tendon-bone autografts, hamstring autografts or allografts are widely used grafts for ACL revision surgeries. Also use of quadriceps autograft for both primary and revision ACL surgeries is in an increasing popularity due to its biomechanical superior properties and less donor site morbidity. However, although several fixation techniques and devices for quadriceps tendon graft fixation on femoral side have been reported, literature lacks about biomechanical studies comparing properties of these different fixation techniques and devices. We aimed to investigate whether there is a difference between the fixation techniques of quadriceps tendon graft by using different fixation techniques and devices on the femoral side in terms of stiffness and amount of slippage in the tunnel. Full-thickness central parts of quadriceps tendons from paired knees of twenty five calf knees were fixed through a 10mm x 25mm tunnel in twenty five paired sheep femurs. Quadriceps tendon patellar side with soft tissue ending fixed with four different fixation devices (adjustable suspensory system (group 1), absorbable interference screw (group 2), titanium interference screw (group 3) and adjustable suspensory system + absorbable interference screw (group 4)) and quadriceps tendon with a patellar bone plug fixed with a titanium interference screw (group 5) were tested in a servohydraulic materials testing machine. 10 samples were included in each group. After applying a preload of 10 N, a cyclic force was applied for 20 cycles from 10N to 110N at a 1 hertz frequency. Amount of slippage in the tunnel was calculated as the difference measured in millimeters between length at 10 N after 20 cycles and starting length at 10 N (Graph 1). To determine the stiffness, a single load-to-failure cycle was performed at a strain rate of 20 mm/min as the last step (Figure 1). Rupture of the graft was not seen in any of the samples. Median values of amount of slippage in the tunnel were 6,41mm, 5,99mm, 3,01mm, 4,83mm, and 3,94mm respectively. Median values of maximum load at failure were 464N, 160N, 350N, 350N and 389N respectively. Amount of slippage in the tunnel was highest in the group 1 and was lowest in the group 3 (p<0.001). Group 1 was found to be most resistant group against load-to-failure test and group 2 was the weakest (p<0.001). However inter-group analyses between group 3 and 5 revealed that, although group 3 had the least slippage in the tunnel, group 5 was better in terms of stiffness, but there was no statistically significant difference (p=0,124 and 0,119 respectively). There was a significant difference between group 2 and 3 in both amount of slippage in the tunnel and stiffness (p=0,001 and 0.028 respectively)(Table 1). Our study revealed that, although quadriceps graft with a bone plug fixed with metal interference screws is widely presumed to be a stable fixation technique, there was no significant difference in terms of stiffness when compared with quadriceps graft with soft tissue ending fixed with a metal interference screw. Although adjustable suspensory device group was the best in the terms of resistance against load-to-failure, it was the worst in terms of amount of slippage from the tunnel. Thus, if a suspensory device is to be used, it must be kept in mind that a strong 20 cycles of intra-operative tension force must be applied to prevent further slippage of the graft in the tunnel which can result in failure of reconstruction. For any figures or tables, please contact the authors directly