Introduction: Conventional metal ankle plates often require secondary removal due to problems such as discomfort or pain. Biodegradable ankle plates and screws have been developed to avoid the need for hardware removal. However, only limited clinical data exists with these new devices. The aim of this study was to retrospectively followup ankle fracture patients treated with biodegradable ankle plates and screws at the Seinäjoki Central Hospital (Finland), and to evaluate clinical outcome and occurrence of postoperative complications in these patients.

Materials and Methods: After ethical committee approval, 57 ankle fracture patients treated with the biodegradable ankle plates and screws (Inion OTPS™, Inion Oy, Tampere, Finland) at the Seinäjoki Central Hospital between March 2004 and September 2006 were invited for a follow-up visit at a private outpatient clinic. Totally 50 patients participated (21 female, 29 male) in the study. There were 36 lateral malleolar fractures (2 with syndesmosis rupture) and 14 bimalleolar fractures (3 with syndesmosis rupture). The average age of the patients was 45 years (SD ± 14, range 18–65) and average weight was 80 kg (SD ± 18, range 45–150). Postoperatively, a cast was applied for 6 weeks. The patients were instructed as follows: First no weight bearing for 2 weeks, then half body weight bearing for 2 weeks, and thereafter gradually towards full weight bearing (with pain restriction). The follow-up included review of each patient’s medical records, evaluation of radiographs (preoperative, postoperative, and the ones taken at the follow-up visit) and fracture reduction classification according to Cedell (anatomic, good, poor), and functional scoring according to Olerud and Molander (0–100). All complications were recorded. In addition, duration of return to work and normal daily activities were asked from each patient.

Results: Average follow-up time was 17 months (SD ± 6.2, range 7–36). No perioperative complications occurred. All fractures healed. Fracture alignment was classified as anatomic in 49 patients and good in 1 case. Average Olerud and Molander ankle score was 86 (SD ± 20, range 15–100). Average duration of return to work was 2.8 months (SD ± 1.3, range 1.5–6), and average duration of return to normal daily activities 3.1 months (SD ± 1.3, range 1.5–6). Postoperative complications: 1 delayed wound healing, 3 cases of deep venous thrombosis, and 4 soft tissue reactions.

Discussion and Conclusions: According to the results of this retrospective study, biodegradable ankle plates and screws provide comparable fracture healing and functional results as those previously reported after use of conventional metal fixation (Lehtonen et al. 2003). Also postoperative complications and their occurrence rates are similar to those seen with metal.

The purpose of this study was to compare the effect of hydrolysis time on the fixation strengths of biodegradable Inion Trinion screws, Mitek Clearfix screws and 2-0 polydioxanone sutures. Complete peripheral, vertical, longitudinal lesions in adult bovine medial menisci were repaired with either a Trinion screw, a Clearfix screw, or a 2-0 polydioxanone (PDS) vertical suture. The ultimate tensile strength of the repair was then tested immediately or after 6, 9, or 12 weeks of incubation (N=6/group/time) at 37C in a saline solution containing antibiotics, antimycotics, and protease inhibitors. Immediately after implantation, the mean failure strengths of the Trinion screw (5215 N) and 2-0 PDS suture (646 N) were significantly (P< 0.05) higher than the Clearfix screw (2610 N). At six weeks the maximum failure loads were as follows: Trinion 2611 N; Clearfix 2012 N; and 2-0 PDS suture 71 N. By 9 weeks the PDS suture lost all fixation strength. The mean maximum failure loads for the Trinion and Clearfix screws at 9 weeks (189 N and 2614 N) and at 12 weeks (165 N and 1011 N) were not statistically different (P> 0.05). Conclusions: The fixation strengths of the Trinion screw and the 2-0 polydioxanone vertical suture are significantly higher than the holding power of the Clearfix screw at time zero. Thereafter the fixation strengths of the Trinion screw and the polydioxanone suture start decreasing, and at 6 weeks no significant difference exists between the three groups. The holding power of the Trinion screw is statistically equivalent to the holding power of the Clearfix screw after 6, 9 and 12 weeks of hydrolysis.

Aims: Serial dilation of the walls of the bone tunnel has been advocated to provide more dense bone-tunnel walls and optimal conditions for rigid fixation in anterior cruciate ligament (ACL) reconstruction with soft tissue grafts. The aim of this study was to compare the initial fixation strength obtained using serial dilation versus conventional extraction drilling in ACL reconstruction. Methods: Initial strength of doubled anterior tibialis tendon grafts fixed with bioabsorbable interference screw was assessed in 21 pairs of human cadaver tibiae. Bone tunnels were created with either serial dilation or conventional extraction drilling (cannulated drill bits). The specimens were subjected to a cyclic-loading test (1500 loading cycles between 50 and 200 N at 0.5 Hz frequency). The specimens surviving the cyclic-loading test were loaded to failure at a rate of 1.0 m/min (single-cycle load-to-failure test). Results: During the cyclic-loading test, no significant stiffness or displacement differences were observed between the two bone-tunnel techniques. Three specimens failed in the serial-dilation group, while there were six failures in the extraction-drilling group. In the subsequent single-cycle load-to-failure test, the average yield load was 473 ± 110 N for the serial-dilation group and 480 ± 115 N for the extraction-drilling group (P=0.97). No significant difference between the two bone-tunnel techniques was found with regard to stiffness nor mode of failure. Conclusions: Serial dilation of the bone-tunnel walls does not increase the initial fixation strength of soft tissue grafts in ACL reconstruction.