Bioabsorbable Screw Fixation Research Articles

Femoral Tunnel Widening after Quadrupled Hamstring Anterior Cruciate Ligament Reconstruction

To evaluate the extent of femoral tunnel widening after quadrupled hamstring anterior cruciate ligament reconstruction using femoral cross pin fixation in contrast to bioabsorbable screw fixation augmented with Endopearl. 16 patients underwent cross pin femoral fixation and the next 15 underwent bioabsorbable screw fixation augmented with Endopearl. The patients were evaluated radiographically for femoral tunnel widening. Standard posteroanterior radiographs of the knee in full extension were taken at postoperative year 2 and 5. The tunnel width was measured at the opening, the widest and the most proximal parts of the femoral tunnel. In the femoral cross pin and bioabsorbable screw fixations, the mean femoral tunnel sizes were 7.6 and 8.0 mm, respectively. The overall mean tunnel widening at all measured sites were 2.7 and 1.8 mm at the 2-year follow-up and were 2.5 and 1.8 mm at the 5-year follow-up, respectively. The femoral tunnel widening was greater in the cross pin than the bioabsorbable screw group, but only the difference in the most proximal part was significant (p=0.01 at year 2 and p<0.001 at year 5). Femoral tunnel widening was greater in femoral cross pin fixation, probably related to the windshield-wiper and bungee-cord effects. It usually occurred in the first 2 years after the operation and remained static thereafter.

Bioabsorbable Versus Metallic Interference Screw Fixation in Anterior Cruciate Ligament Reconstruction: A Meta-Analysis of Randomized Controlled Trials

The aim of the study was to investigate the outcomes between bioabsorbable and metallic screw fixation in anterior cruciate ligament (ACL) reconstruction. Randomized controlled trials (RCTs) comparing bioabsorbable versus metallic screw fixation in single-bundle ACL reconstruction were identified systematically, and the outcomes were analyzed in terms of infection rate, knee joint effusion, Lysholm score, International Knee Documentation Committee final score, pivot-shift test, and KT-1000/-2000 arthrometer (MEDmetric, San Diego, CA) measurements. The type of grafts was ignored in the meta-analysis. Standard mean difference (SMD) or risk ratio (RR) with 95% confidence interval (CI) was calculated by a fixed-effects or random-effects model. Heterogeneity across the studies was also assessed. We included 10 studies comprising 790 patients who were treated by bioabsorbable versus metallic screw fixation for single-bundle ACL reconstruction. The meta-analyzed results of these studies showed that there was no statistically significant difference between bioabsorbable and metallic screw fixation in infection rate (RR, 0.91; P = .87; 320 patients in 5 studies), KT-1000/2000 arthrometer testing (SMD, -0.01; P = .95; 438 patients in 7 studies), pivot-shift testing (RR, 1.06; P = .82; 260 patients in 4 studies), International Knee Documentation Committee final score (RR, 0.87; P = .63; 300 patients in 5 studies), and Lysholm score (SMD, 0.03; P = .89; 204 patients in 4 studies). The incidence of knee effusion was higher in the bioabsorbable screw group (RR, 2.57; P = .04; 421 patients in 4 studies). There was no significant difference in measurement results of knee joint stability or knee joint function outcome between bioabsorbable and metallic interference screws. Knee joint effusion is more common after ACL reconstruction with bioabsorbable interference screw fixation than with metallic interference screw fixation. More high-methodologic quality randomized controlled trials would be helpful in further meta-analysis. Level I, meta-analysis.

Bioabsorbable Screw Fixation of the Syndesmosis in Unstable Ankle Injuries

Bioabsorbable Screw Fixation of the Syndesmosis in Unstable Ankle Injuries

Femoral fracture following knee ligament reconstruction surgery due to an unpredictable complication of bioabsorbable screw fixation: a case report and review of literature

We report an unusual case of femoral fracture from minimal trauma, due to the rapid disappearance of a bioabsorbable interference screw used for reconstruction of the posterolateral corner of the knee. The literature on bone tunnel fractures following knee ligament reconstruction surgery is also reviewed.

Mycobacterium fortuitum infection after anterior cruciate ligament reconstruction using a polylactic acid bioabsorbable screw: Case report

We report a case of pretibial sinus and abscess after anterior cruciate ligament reconstruction using a polylactic acid tricalcium phosphate bioabsorbable screw for tibial fixation. Mycobacterium fortuitum was identified as the pathogen after specific mycobacterial cultures were obtained from operative specimens. M. fortuitum is a known but rare cause of periprosthetic infection. Diagnosis is often delayed as routine microbiological cultures do not utilise specific culture requirements for mycobacterial growth. There have been several reports in the literature of sterile abscesses associated with bioabsorbable screws. To our knowledge, this is the first case report of a non-tuberculous mycobacterial infection associated with a bioabsorbable implant. This case illustrates that post-operative Mycobacterium infection can occur as a complication of ACL reconstruction with bioabsorbable screw fixation and should be considered in the differential diagnosis of post-operative periprosthetic infection.

Tunnel Enlargement after Double-Bundle Anterior Cruciate Ligament Reconstruction (SS-43)

Sixty patients were randomized with closed envelopes into either double-bundle or single-bundle anterior cruciate ligament reconstruction with hamstring tendons and bioabsorbable screw fixation. After 2-year follow-up, tunnel enlargement was determined by MRI measuring the widths perpendicular to the long axis of the tunnels on an oblique coronal and sagittal plane. Double-bundle ACL reconstruction technique results in less tunnel enlargement in each tunnel on tibial side than the single-bundle technique with similar fixation methods, graft material, and rehabilitation.

Bioabsorbable Screw Fixation of the Syndesmosis in Unstable Ankle Injuries

Bioabsorbable Screw Fixation of the Syndesmosis in Unstable Ankle Injuries

Bioabsorbable Screw Fixation of the Syndesmosis in Unstable Ankle Injuries

The purpose of this study was to retrospectively evaluate the clinical and radiographic outcomes of the medium and long-term results of Bionx bioabsorbable screw fixation of the ankle syndesmosis in unstable ankle injuries. Between May 2001 and July 2006, 75 patients underwent syndesmotic fixation with a bioabsorbable screw. All patients had closed primary ankle fractures or dislocations with syndesmotic instability. Open reduction and internal fixation of the ankle fracture was performed using current standard orthopaedic technique. Patients were followed clinically and radiographically from 12 to 74 months with the mean being 32.5 months. Seventy of 75 patients (93%) returned for the final evaluation. Mean AOFAS Ankle-Hindfoot score was 90 of 100 and mean VAS for pain was 1.8 out of 10 at the time of final followup. No patients in this population showed radiographic syndesmotic instability, loss of mortise congruency, or post-traumatic arthritis in the sigmoid notch area at final followup. No patients required revision surgical fixation of the syndesmosis. This study demonstrates that the use of bioabsorbable screw for syndesmotic fixation is associated with satisfactory restoration of ankle function and syndesmotic stability.

Biomechanical Evaluation of Bioabsorbable versus Metallic Screws for Posterior Cruciate Ligament Inlay Graft Fixation

Background Although a tibial inlay technique for posterior cruciate ligament reconstruction is advantageous, metallic screw fixation of the bone block is required. This may pose problems for future surgery (eg, osteotomies, total knee replacement). Hypothesis There is no significant difference in the biomechanical integrity of bone block fixation using stainless steel versus bioabsorbable screw fixation of the tibial inlay graft in posterior cruciate ligament reconstruction. Study Design Controlled laboratory study. Methods Fourteen human cadaveric knees were randomized to receive either stainless steel or bioabsorbable screw fixation of a bone—patellar tendon—bone graft. Cyclic tensile testing of each construct was performed, followed by a load-to-failure test. Digital video digitization was used to optically determine tendon graft deformation. Results Cyclic creep deformation showed no significant difference between the 2 groups (P = .8). The failure load (stainless steel, 461 ± 231 N; bioabsorbable, 638 ± 492 N; P = .7) and linear stiffness (stainless steel, 116 ± 22 N/mm, bioabsorbable, 106 ± 44 N/mm; P = .6) also showed no significant difference between the 2 groups. Optically measured graft deformation was not significant for distal (P = .7) and midsubstance (P = .8) regions, while proximal deformation was significantly higher for bioabsorbable fixation (P = .02). All samples failed at the tibial insertion site with the tibial bone block fracturing at the screws. Conclusion Bioabsorbable screw fixation using a tibial inlay technique does not compromise the strength and stiffness characteristics afforded by metallic fixation. From a biomechanical perspective, bioabsorbable screws are a viable alternative to metal in the context of tibial inlay reconstruction. Clinical Relevance Use of bioabsorbable fixation can potentially eliminate future hardware problems after posterior cruciate ligament reconstruction using a tibial inlay technique.

Comparison of Bioabsorbable Versus Metallic Implant Fixation for Physeal and Epiphyseal Fractures of the Distal Tibia

Transepiphyseal screw fixation of displaced distal tibial epiphyseal fractures is the most common method of treatment for these intraarticular injuries. Recent literature indicates that retained transepiphyseal metallic screws cause an increase in ankle joint contact pressure, thus favoring screw removal. Our hypothesis is that bioabsorbable screw fixation is an alternative to metallic fixation, which offers similar results without the need for screw removal. This is a retrospective review of distal tibial epiphyseal ankle fractures treated with screw fixation. Two groups, those treated with bioabsorbable screw fixation (group B, n = 24) and those with metallic screw fixation (group M, n = 26), were compared (t test) for differences in clinical and radiographic outcomes. Analysis of demographic data revealed no significant differences between groups for sex, ethnicity, age, and height. Group B was significantly heavier than group M (67.4 vs 55.6 kg; P = 0.0496). Each group had a similar number of Salter-Harris types III and IV medial malleolus fractures and transitional fracture types. There was no significant difference between groups in the time from injury to fixation or in operative time. Radiographically, there were no nonunions in either group, and at final follow-up, 1 patient in group B had distal tibial joint line irregularity versus 3 in group M. Clinically, there were no significant differences between groups in time to full weight bearing or time to full activities.There were fewer complications in group B. A single case of loss of reduction requiring revision fixation occurred in each group. There was one documented growth arrest in group M and 2 suspected growth arrests in each group. Two patients in group M were successfully treated for a superficial wound infection with oral antibiotics. Fourteen patients in group M underwent planned screw removal. Bioabsorbable screw fixation can be used for distal tibial epiphyseal fractures with no increase in operative time, nonunion rate, number of unplanned secondary surgeries, or other complications. The use of bioabsorbable screws eliminates the need for epiphyseal screw removal. A prospective randomized study is planned to eliminate the potential selection bias and to standardize clinical and radiographic follow-up. Level III, case-control study.

Tunnel Enlargement After Double-Bundle Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Study

The aim of this study was to compare tunnel enlargement in patients with double-bundle and single-bundle anterior cruciate ligament (ACL) reconstruction. Sixty patients were randomized by closed envelopes into 2 different groups of ACL reconstruction with hamstring tendons: double-bundle technique with bioabsorbable screw fixation (n = 35) and single-bundle technique with bioabsorbable screw fixation (n = 25). Magnetic resonance imaging evaluation was performed in 53 patients (88%) (32 in double-bundle group and 21 in single-bundle group) for a mean of 27 months' follow-up (range, 24 to 36 months). Tunnel enlargement was determined by digital measurement of the widths perpendicular to the long axis of the tunnels on an oblique coronal and sagittal plane. The magnetic resonance imaging measurements were compared with the intraoperative drill diameter. No significant differences were found between the double-bundle group and the single-bundle group in tunnel enlargement on the femoral side. However, on the tibial side, tunnel enlargement was greater in the single-bundle group than in the double-bundle group in each tunnel (P = .051). In all knees, tunnel enlargement both on the tibial side and on the femoral side correlated significantly with the anterior and rotational laxity of the operated knee. In the double-bundle group, no tunnel communication between the anteromedial and posterolateral tunnels was seen in any of the patients on either the tibial side or femoral side. This prospective, randomized study showed that our double-bundle ACL reconstruction technique results in less tunnel enlargement in each tunnel on the tibial side than the single-bundle technique with similar fixation methods, graft material, and rehabilitation. In addition, no tunnel communication was observed in the patients undergoing double-bundle ACL reconstruction. The clinical results were good in both groups. However, the patients who had more tunnel enlargement had significantly more anterior and rotational laxity of the operated knee as well. Level I, therapeutic randomized controlled trial.

A Comparison between a Retrograde Interference Screw, Suture Button, and Combined Fixation on the Tibial Side in an All-Inside Anterior Cruciate Ligament Reconstruction

Background Effective soft tissue graft fixation to the tibial tunnel in all-inside anterior cruciate ligament reconstructions has been reported to be a problem and may lead to retrograde pullout at ultimate load testing. Hypothesis A combined retrograde bioabsorbable screw and cortical-cancellous suture button suspension apparatus would gain stiffness from the button and strength from the screw, thus providing for a larger pullout ultimate load, yield load, and stiffness when compared with either fixation alone in an all-inside anterior cruciate ligament reconstruction. Study Design Controlled laboratory study. Methods Eighteen porcine tibias (average bone mineral density of 1.46, measured by dual-energy x-ray absorptiometry scan) and 18 bovine extensor tendon allografts were divided into 3 groups retrograde bioabsorbable screw fixation, cortical-cancellous suture button suspension apparatus fixation, and combined fixation in the tibia, with 6 specimens per group. They were biomechanically tested with cyclic (500 cycles, 50-250 N, 1 Hz) and load-to-failure (20 mm/min) parameters. Results During cyclic testing, the retrograde screw—only group had a larger cyclic displacement (2.98 ± 2.28 mm) than the suture button with retrograde screw combination group (1.40 ± 0.34 mm). The combination fixation group also produced a higher cyclic stiffness (161.93 ± 61.81 N/mm) than the retrograde screw—only group (91.59 ± 43.26 N/mm). In load-to-failure testing, the retrograde screw with suture button combination group withstood significantly higher initial failure forces (873.87 ± 148.74 N) than the retrograde screw—only (558.44 ± 126.33 N) and suture button—only (121.76 ± 40.57 N) groups. Additionally, ultimate loads were also significantly higher for the combination group (1027 ± 157.11 N) than either the retrograde screw group (679.00 ± 109.44 N) or the suture button group (161.00 ± 29.27 N). The retrograde screw with suture button combination group showed significantly higher pullout stiffness (152.50 ± 46.37 N/mm) than either the retrograde screw—only group (78.31 ± 12.85 N/mm) or the suture button—only group (25.79 ± 9.30 N/mm). Conclusion Soft tissue grafts fixed with a combination of a retrograde screw and a suture button were able to withstand higher initial failure and ultimate failure loads and were also stiffer than grafts fixed with either a retrograde screw or a suture button alone. Clinical Relevance These findings may prove useful in providing additional stability when using an all-inside technique in a difficult case, or in a patient with poor bone stock, and may also be useful as an alternative to more commonly used tibial tunnel soft tissue fixation techniques.

Comparison of the bioabsorbable and metal screw fixation after ACL reconstruction with a hamstring autograft in MRI and clinical outcome: a prospective randomized study

There has never been an MRI study of tunnel widening comparing bioabsorbable to metal screw fixation in autologous hamstring anterior cruciate ligament (ACL) reconstruction. We randomized 62 patients to hamstring ACL reconstruction with either a bioabsorbable (n=31) or metal screw (n=31) fixation. The evaluation methods were clinical examination, KT-1000 arthrometric measurement, the International Knee Documentation Committee and Lysholm scores, and MRI. There were no differences between the groups preoperatively. Fifty-five patients (89%) were available at a minimum of 2-year follow-up (range 24-36 months). There was tunnel widening in both groups, but the increase was significantly greater in the AP dimension of the femoral tunnel in the bioabsorbable screw group compared to metal group (P=0.01). The tibial tunnels showed no intergroup difference. Ninety-four percent of the knees were normal or nearly normal according to the IKDC scores and the average Lysholm score was 91 with no intergroup difference. The follow-up AP tibial tunnel diameter was smaller with normal knee laxity compared to abnormal knee laxity. The graft failure rate in the bioabsorbable screw group was 23% (7/31 patients) and 6% (2/31 patients) in the metal screw group. The use of bioabsorbable screws resulted in more femoral tunnel widening, and more graft failures compared to metal screws. The tunnel widening in the tibia was associated with the knee laxity (P=0.02).

Double-Bundle Anterior Cruciate Ligament Reconstruction Using Hamstring Autografts and Bioabsorbable Interference Screw Fixation

Background Conventional anterior cruciate ligament reconstruction techniques have focused on restoration of the anterome-dial bundle only, which, however, may be insufficient in restoring the rotational stability of the knee. Hypothesis Rotational stability of the knee is better when using a double-bundle technique instead of a single-bundle technique for anterior cruciate ligament reconstruction. Study Design Randomized controlled clinical trial; Level of evidence, 1. Methods Seventy-seven patients were randomized into 3 different groups for anterior cruciate ligament reconstruction with hamstring tendons: double-bundle with bioabsorbable screw fixation (n = 25), single-bundle with bioabsorbable screw fixation (n = 27), and single-bundle with metallic screw fixation (n = 25). The evaluation methods were clinical examination, KT-1000 arthrometric measurement, and the International Knee Documentation Committee and Lysholm knee scores. Results There were no differences between the study groups preoperatively. Seventy-three patients (95%) were available at a minimum 2-year follow-up (range, 24–35 mo). The rotational stability of the knee, as evaluated by the pivot-shift test, was the best in the patients in the double-bundle group. In addition, the patients in the single-bundle groups had more graft failures than those in the double-bundle group. Concerning the anterior stability of the knee as measured with the KT-1000 arthrometer, the group differences were not statistically significant. No significant differences were found between the groups in knee scores. Conclusion Rotational stability of the knee is better when using the double-bundle technique instead of the single-bundle technique in anterior cruciate ligament reconstruction.

Double-Bundle vs. Single-Bundle Anterior Cruciate Ligament Reconstruction: Prospective, Randomize Clinical Study (SS-08)

Sixty-five patients were randomized into either double-bundle (n = 35) or single-bundle (n = 30) ACL reconstruction with hamstring tendons and bioabsorbable screw (Hexalon, Inion Company, Finland) fixation in both group. At the 1-year follow-up, the rotational stability and the early anterior stability were significantly better in the double-bundle group than in the single-bundle group. In addition, none of the patients in double-bundle group had graft failure, while four patients in the single-bundle group had. However, knee scores were equal at the follow-up, and all the results were significantly better at the follow-up than preoperatively, in both groups. The purpose of this prospective, randomize clinical study is to compare the outcomes of anterior cruciate ligament reconstruction when using either double-bundle or single-bundle technique and bioabsorbable interference screw fixation with both techniques. Sixty-five patients were randomized into either double-bundle (n = 35) or single-bundle (n = 30) ACL reconstruction with hamstring tendons and bioabsorbable screw (Hexalon, Inion Company, Finland) fixation in both group. The evaluation methods were clinical examination, KT-1000 arthrometer measurements, radiographic evaluation, as well as International Knee Documentation Committee (IKDC), and Lysholm knee scores. There were no differences between the study groups preoperatively. For the minimum of 1-year follow-up (range, 12 to 19 months), 31 patients of the double-bundle group and 27 patients of the single-bundle group were available (89%). At the follow-up, the rotational stability, as evaluated by pivot shift test, was significantly better in the double-bundle group than in the single-bundle group. Also, the early anterior stability was significantly better with double-bundle technique, although at 1-year follow-up, no significant difference between the groups was found anymore. In addition, none of the patients in double-bundle group had graft failure, while four patients in the single-bundle group had. However, knee scores were equal at the follow-up, and all the results were significantly better at the follow-up than preoperatively, in both groups. Rotational stability and early anterior stability were significantly better with double-bundle technique than with single-bundle technique in ACL reconstruction with hamstring autografts and bioabsorbable screw fixation. However, both fixation techniques improved patients’ performance.

Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective, randomize clinical study

Anatomical observation and biomechanical studies have shown that the anterior cruciate ligament (ACL) mainly consists of two distinct bundles, the anteromedial (AM) bundle and posterolateral (PL) bundle. Conventional single-bundle ACL reconstruction techniques have focused on the restoration of the AM bundle while giving limited attention to the PL bundle. The purpose of this prospective, randomized clinical study is to compare the outcomes of ACL reconstruction when using either double-bundle or single-bundle technique and bioabsorbable interference screw fixation, and similar rehabilitation with both techniques. Sixty-five patients were randomized into either double-bundle (n = 35) or single-bundle (n = 30) ACL reconstruction with hamstring tendons and bioabsorbable screw (Hexalon, Inion Company, Tampere, Finland) fixation in both groups. The evaluation methods were clinical examination, KT-1000 arthrometer measurements, radiographic evaluation, as well as International Knee Documentation Committee and Lysholm knee scores. There were no differences between the study groups preoperatively. For an average of 14 months of follow-up (range 12-20 months), 30 patients of the double-bundle group and 29 patients of the single-bundle group were available (91%). At the follow-up, the rotational stability, as evaluated by pivot shift test, was significantly better in the double-bundle group than in the single-bundle group. However, in anterior stability of the knee, there was no significant difference between the groups. None of the patients in the double-bundle group had graft failure, while four patients in the single-bundle group had. In addition, knee scores were equal at the follow-up, and all the results were significantly better at the follow-up than preoperatively, in both groups.

Bioabsorbable screw fixation for the treatment of ankle fractures

BackgroundSelf-reinforced poly(L/DL)lactide 70:30 (SR-PLA70) retains its strength in bone for 24 weeks, whereas self-reinforced poly-L-lactide (SR-PLLA) retains its strength for over 36 weeks. In this prospective randomized study, bioabsorbable 4.5-mm SR-PLA70 screws were compared with SR-PLLA screws in the treatment of displaced ankle fractures in adults. MethodsSixty-two patients with ankle fractures needing operative treatment were randomized into two groups. Comminuted fractures needing plating were excluded. In total 54 of 62 patients were followed up for 1 year by clinical evaluation, radiographs, and Olerud-Molander score. ResultsThe study groups differed significantly only in the mean duration of sick leave (SR-PLA70, 60 days; SR-PLLA, 65 days; P = 0.02). At the 1-year follow-up, syndesmotic ossification was more common in the SR-PLA70 group (5 versus 1 patient, not significant). Radiologically, the screw channel had not disappeared in any of the patients by the 1-year follow-up. ConclusionsBoth implant types proved to have good biocompatibility. SR-PLA70 and SR-PLLA screws are suitable in selected cases for the fixation of ankle fractures, but the mechanical stability of the fixation has to be carefully monitored perioperatively.

Biomechanical Study of Anterior Cervical Corpectomy and Step-Cut Grafting With Bioabsorbable Screws Fixation in Cadaveric Cervical Spine Model

An in vitro biomechanical study. To determine the initial stability of a novel construct in a 1-level cadaveric cervical spine model by comparing it with a conventional method. Lots of endeavors have been made to enhance fusion rates and reduce complications in the anterior cervical spine procedure. There were 12 fresh human cadaveric cervical spines (C3-C7) randomly divided into 2 groups: group 1, 1-level corpectomy of C5 and step-cut grafting with bioabsorbable screw fixation (SCAS); and group 2, 1-level corpectomy of C5 and strut grafting with anterior plate fixation (SP). For each specimen, the intact underwent a flexibility test first, followed by the instrumented construct. Rotational angles of the C4-C6 segment were measured to study the immediate stability of anterior cervical corpectomy and SCAS, compared with the intact and anterior cervical corpectomy and SP. Both anterior cervical corpectomy with SCAS and with SP significantly (P < 0.01) decreased the motions of C4-C6 in all 6 degrees of freedom after instrumentation. Compared with anterior cervical corpectomy and SP, anterior cervical corpectomy and SCAS had higher stability (P < 0.05) in extension, and comparable stability (P > 0.05) in flexion and axial rotation, but lower stability (P <or= 0.05) in lateral bending. Anterior cervical corpectomy and SCAS, a novel method of anterior cervical spine decompression and reconstruction, was introduced. The in vitro biomechanical study showed that anterior cervical corpectomy and SCAS had sufficient immediate stability except for the lateral bending, compared with anterior cervical corpectomy and SP, in a 1-level cadaveric cervical spine model. However, an animal experimental in vivo evaluation of anterior cervical corpectomy and SCAS still has to be performed.

A Biomechanical Comparison of Bosworth and Poly-L Lactic Acid Bioabsorbable Screws for Treatment of Acromioclavicular Separations

The purpose of this study was to determine the failure load of intact coracoclavicular ligaments and the pullout strength of a poly-L lactic acid screw (PLLA, Linvatec, Largo, FL) compared with a titanium screw (Bosworth, Stryker Howmedica Osteonics, Allendale, NJ) in the repair of fifth-degree acromioclavicular separations. Biomechanical cadaveric study. The ultimate tensile strength of coracoclavicular ligaments was determined using a servohydraulic testing machine (MTS, Eden Prairie, MN) by creating grade V acromioclavicular separations. Titanium Bosworth screws and Linvatec PLLA screws were placed across the reduced coracoclavicular joint and through the base of the coracoid process of right and left matched cadaveric shoulder specimens, respectively. The axial pullout strength was determined by MTS uniaxial tensile testing along the screw axis to determine the ultimate fixation failure load at a rate of 1 mm/second. Intact coracoclavicular ligaments required an axial load of 340.15 +/- 100.77 N to fail. The bioabsorbable PLLA screw provided fixation strength that was significantly less than the Bosworth screw fixation strength: 272.01 +/- 63.26 and 367.01 +/- 111.54 N, respectively (P < .05, paired t test). The titanium Bosworth screw restored strength to the acromioclavicular joint equivalent to the intact coracoclavicular ligament; however, the bioabsorbable PLLA screw fixation was significantly weaker than the intact ligaments and the Bosworth repair. Titanium Bosworth screws supply more strength of fixation in grade V acromioclavicular separations than the PLLA screw tested in this study.

Syndesmotic disruptions of the ankle

Studies suggest that for treatment of syndesmotic disruptions of the ankle, bioabsorbable screw fixation and conventional stainless steel screw fixation lead to similar ranges of dorsal motion, medial clear space, duration of sick leave, and complications. Further randomized studies with a large sample size and long period of follow-up are needed to verify that clinical outcomes and quality of life are similar between treatment groups.