Bioabsorbable Fixation Devices Research Articles

Biomechanical comparison of different implants for PIP arthrodesis

BackgroundSurgical correction of hammertoe deformities with arthrodesis of the proximal interphalangeal joint (PIP) is one of the most frequent forefoot procedures. Recently, new intramedullary fixation devices for PIP arthrodesis have been introduced. The aim of this study was to compare a newly developed absorbable intramedullary implant made of magnesium (mm.PIP), an already available intramedullary implant made of titanium (PipTree), and the classical Kirschner-wire (K-wire). MethodsThe three intramedullary devices (mm.PIP, PipTree, and K-wire) for PIP arthrodesis were compared. A classical arthrodesis of the PIP joint was performed on fifty-four composite synthetic bone pairs. After arthrodesis, torsional load, weight-bearing and cyclic load tests were performed, and stability of the synthetic bone pairs was analyzed. ResultsThe mm.PIP was the most torsion resistant (mm.PIP vs. PipTree and K-wire, p < 0.001). The PipTree showed the best overall stability during cyclic weight-bearing simulation (PipTree vs. mm.PIP and K-wire, p < 0.001). K-wire demonstrated the highest breaking loads during bending tests (K-wire vs. mm-PIP and PipTree, p < 0.001). ConclusionBiomechanical properties of two new intramedullar implants, the bioresorbable mm.PIP made of magnesium and the PipTree made of titanium, were found to be comparable to the biomechanical properties of a K-wire which is commonly used for this procedure. Future work should be directed towards a clinical assessment of the bioabsorbable fixation devices for hammertoe procedures.

Bioabsorbable Anchors for Medial Patellofemoral Ligament Reconstruction

Acute dislocation of the patella is a very common injury of the knee. In more than 90% of the cases the medial patellofemoral ligament (MPFL) is injured. Reconstruction of the MPFL has become a popular soft tissue procedure, which reduces hospitalization and the rehabilitation period. Bioabsorbable materials, in form of screws and anchors are ideal for soft fixation to bones in orthopedics. We would like to present our experience and short-term results after MPFL reconstruction with semitendinous autograft and bioabsorbable fixation devices. 10 patients were involved in this study with PF joint instability, who underwent to MPFL reconstruction. In order to evaluate the functional outcome of the procedure we applied the Tegner Lysholm scoring system before and after 3 Months of surgery. MPFL reconstruction significantly improved the functionality of the PF joint. Gender distribution of the studied group was: 7 female with an average age of 25 5,03 SD and 3 male patients with an average age of 29 1 SD. The key for the success in MPFL reconstruction is the positioning of the femoral tunnel, followed by an isometric tensioning of the graft. Bioabsorbable materials reduce inflammatory, and foreign body response facilitating biointegration of the autograft.

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.

Creep Analysis of PLLA

Bioabsorbable fixation device failures occur clinically on occasion, with failures often brittle in nature. However, creep failure may also occur for implants that are subjected to sustained loads whereby the device may slowly deform over time, perhaps leading to fracture. Even without fracture occurring, the device may become too distorted to function. There is little in the literature regarding creep performance of bioabsorbable devices such as plates and screws. This study investigated the creep characteristics of craniofacial plates and screws made of a copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid. Four-hole straight plates were attached to 2 rectangular portions of synthetic bone substrate using 2.0-mm-diameter bioabsorbable screws (2 screws used to attach the plate to each substrate portion). The constructs were submersed in phosphate-buffered saline (pH 7.4, 37°C) and placed in tension with 3 load configurations, that is, 230, 460, and 1140 g, for at least 6 days. Creep rate was constant at a given load and was directly proportional to load (4.7, 14.3, and 33.3 μm/h for 230-, 460-, and 1140-g loads, respectively). The data conformed well to basic creep theory analysis and provided an estimate of the absolute viscosity of the polymer of 8.7 × 10(12) ± 0.81 × 10(12) P (average ± SEM), which is intermediate between that of soft and hard tissue, although closer to the latter. Surgeons and engineers should be aware of the potential for creep to occur when designing bioabsorbable implants and investigating new clinical applications.

Controlling degradation rate of poly(lactic acid) for its biomedical applications

Poly(lactic acid) (PLA) is widely used in many different biomedical applications due to its biocompatibility, complete biodegradability, and non-toxic degradation products. However, PLA may be limited in particularly long degradation, which is not always desirable in many biomedical applications. In this short review, we summarized some of the most recent studies on controlling the degradation rate of PLA, employing copolymerization, blending, additives and irradiation. This review discussed the pros and cons of those methods considering their applications to bioabsorbable fixation or drug delivery devices. We also suggested the design parameters for PLA treatment for its wide applicability to biomedical fields.

Multispecialty Contralateral Study of Clinical Experience With the Ultratine Forehead Fixation Device: Evolution of the Original Endotine Device

Multispecialty Contralateral Study of Clinical Experience With the Ultratine Forehead Fixation Device: Evolution of the Original Endotine Device

Outcomes and Complications Based on Experience With Resorbable Plates in Pediatric Craniosynostosis Patients

The structure and functional relationship of polymers have long been the purview of engineers and polymer chemists. Bioabsorbable fixation devices have been used for decades as dissolvable suture meshes and, recently, routinely by orthopedic surgeons. During the past decade, bioabsorbable fixation systems have become available for use by craniomaxillofacial surgeons for cranial vault remodeling. This study evaluates the application of a bioabsorbable fixation system in reconstructive craniofacial procedures in a pediatric population. We reviewed 146 cases of cranial vault reconstruction including 98 boys and 48 girls ranging from 2 months to 16 years (mean, 15 months) in age. The procedures were performed for 6 years between January 1998 and June 2004. Bioabsorbable plates and screws were used in each case; most of these cases were craniosynostosis reconstructions. There were 69 cases of frontal sagittal craniosynostosis, 36 metopic, 20 unicoronal, 12 bicoronal, 5 lamboid, 2 deformational plagiocephaly, and 2 multiple fusion of sutures. Postoperative evaluation consisted of clinical examination and three-dimensional computed tomography scan reconstructions at 3, 6, and 12 months. Items specifically screened for on the clinical examination included wound healing, signs of infection, and palpability of implant through the skin. Six patients had palpable plates, 2 patients had palpable screw, and 5 patients had infection at the incision site (of which only 3 were treated with inpatient care including incision drainage and intravenous antibiotics). Our experience has been overwhelmingly positive, and we feel that our results suggest that resorbable fixation is a superior option in pediatric plastic and craniofacial surgery.

The effect of low intensity ultrasound and bioabsorbable self-reinforced poly-L-lactide screw fixation on bone in lateral malleolar fractures

There are no previous reports of low intensity pulsed ultrasound therapy in connection with bioabsorbable fracture fixation. In this randomised, prospective, double-blind and placebo-controlled study, the effects of ultrasound on bone mineral density and bone healing were examined in lateral malleolar fractures fixed with a bioabsorbable self-reinforced poly-L-lactide screw (SR-PLLA). Thirty adult patients with SR-PLLA screw-fixed lateral malleolar fracture underwent ultrasound therapy 20 min daily for 6 weeks. Half of the patients were provided randomly with a sham ultrasound device. Bone mineral density and bone healing were assessed by dual-energy X-ray absorptiometry (DXA) and by radiographs. Bone mineral density of the fractured lateral malleolus tended to increase slightly during 12 weeks of follow-up. The increase was symmetrical and statistically non-significant between the ultrasound and non-ultrasound group. All the fractures healed uneventfully. The biocompatibility of the bioabsorbable SR-PLLA fixation device and low intensity pulsed ultrasound was good. Despite the slight tendency for more frequent callus formation in the ultrasound group, no statistically significant effect of low intensity pulsed ultrasound on lateral malleolar fracture healing could be observed. It was not possible to observe any statistically significant effect of low intensity pulsed ultrasound on lateral malleolar fracture healing in this study. Further studies are needed to examine the role of ultrasound therapy in the healing of fractures treated with bioabsorbable fixation devices.

The radiographic examination of bioabsorbable internal fixation devices in maxillofacial surgery

目的 通过术前和术后影像学比较研究观察生物可吸收内固定系统(夹板与螺钉)植入人体后的长期结果.方法对17位颌面部骨折的患者在植入可吸收夹板与螺钉内固定后的6、9、12、18、24个月时行三维CT和/或全景片检查.同时复查患者的伤口愈合、骨端固定、咬合关系恢复等情况.结果17位患者在术后1年内检查时螺钉的透射影像均没有明显的改变;18个月时螺钉的空洞基本被骨小梁充填;2年时螺钉的空洞完全被正常的骨小梁代替.临床检查局部伤口、骨段愈合均恢复良好,咬合关系正常.结论影像学表明可降解内固定系统在植入人体后18～24个月得到了完全的降解,完全达到临床治疗上的生理骨愈合。

Are there any complications with bioabsorbable fixation devices? A 10 year review in orthognathic surgery

<h2>Abstract</h2> Bioabsorbable fixation devices have been used in our departments between November 1991 and November 2001 in orthognathic surgery. The aim of this retrospective study was to assess all complications experienced during this time period, when we have operated 163 patients who have undergone 329 orthognathic osteotomies fixated with bioresorbable devices. No postoperative intermaxillary fixation was used. Light guiding elastics were used for 5 to 7 weeks. Patients' acceptance was generally excellent and very few complications occurred during this follow-up of 10 years. The complications were minor and did not affect the end results of the operations. Minor complications occurred in 14 patients (8.6%). Only one patient (0.6%) had a postoperative infection with elevated infection parameters. The other minor complications consisted mainly of dehiscence of the wound and plate exposure together with granulation tissue in the operation field. The rest of the complications occurred in the beginning of our study, when large screw heads on top of the bone irritated the patient and had to be removed. Insufficient fixation resulted in open bite in three patients (1.8%) in the beginning of the trial use of new devices, which no longer are used. Based on our experience, bioresorbable devices are safe to be used in orthognathic procedures. However, there is a learning curve, as there is with all new methods introduced.

Paper #170 Arthroscopic repair of osteochondral lesions in the knee with a new bioabsorbable SR-PLLA fixation device

Paper #170 Arthroscopic repair of osteochondral lesions in the knee with a new bioabsorbable SR-PLLA fixation device

Self-reinforced bioabsorbable versus metallic fixation systems for metacarpal and phalangeal fractures: a biomechanical study.

Bioabsorbable fixation devices offer a useful option to treat small bone fractures of the hand if the prerequisite of reliable and stable osteofixation is met. We compared the stabilities of various bioabsorbable fixation devices with metallic fixation devices by using an oblique osteotomy model in radial to ulnar orientation. The 1.5-mm, self-reinforced, poly-L-lactide (SR-PLLA) pins provided fixation rigidity comparable with 1.5-mm K-wires in dorsal and palmar apex bending, whereas in lateral apex bending and in torsion the rigidity was equal to that of 1.25-mm K-wires. The 2.0-mm, self-reinforced, poly-L/DL-lactide (SR-P(L/DL)LA) 70/30 screws provided rigidity comparable with that of 1.5-mm K-wires in all testing modes. The bioabsorbable plate considerably enhanced the bending stabilities of the fixation system, but a single interfragmentary screw provided only limited rotational rigidity. The results show that by using ultra-high strength self-reinforced implants adequate fixation stability for hand fracture fixation can be achieved.

Adverse Tissue Reactions to Bioabsorbable Fixation Devices

Among 2528 patients operated on using pins, rods, bolts, and screws made of polyglycolic acid or polylactic acid, 108 (4.3%) were affected by a clinically significant local inflammatory, sterile tissue reaction. The three most common indications for the use of these fixation devices were a displaced malleolar fracture, a chevron osteotomy for hallux valgus, and a displaced fracture of the radial head. In 107 patients, the reaction was elicited by a polyglycolic acid implant, and in one patient by a polylactic acid implant. The incidences were 5.3% (107 of 2037) and 0.2% (one of 491), respectively. The adverse tissue responses to polyglycolic acid were seen 11 weeks after the operation, on average, whereas the reaction to polylactic acid occurred 4.3 years after fixation of an ankle fracture. The mild reactions consisted of a painful erythematous papule of a few weeks' duration. Those of medium severity had a sinus that discharged remnants of the implant for up to 6 months. In the patients affected by severe reactions, extensive osteolytic lesions developed at the implant tracks. The histopathologic picture was that of a nonspecific foreign body reaction. In four patients with vigorous reactions, an arthrodesis of the wrist or ankle later was necessary because of severe osteoarthritis. Several markers of increased risk of the occurrence of a foreign body reaction were found. These included a poorly vascularized bone section such as scaphoid, use of a quinone dye as an additive in the polymer, and an implant geometry with large surface area (screw versus pin or rod). For polyglycolic acid implants, the risk of an adverse tissue response in a given clinical situation can be estimated from the findings of this study. For slow degrading polymers like polylactic acid, however, the ultimate biocompatibility still is unsettled, and additional clinical research with long followup is required.

Retrospective study of nonsyndromic craniosynostosis treated over a 10-year period.

Since the first operation for premature suture closure in North America in 1888, there have been some fundamental changes in the treatment of these sutures, the latest being the U.S. Food and Drug Administration's 1996 approval of a bioabsorbable fixation device. This retrospective study documents our experience with procedures performed primarily by Bennie J. van R. Zeeman for isolated craniosynostosis over a 10-year period. It was an attempt to evaluate factors affecting outcome and to determine the safety of the techniques used to correct these congenital defects. Diagnoses included plagiocephaly (116) and sagittal (44), metopic (17), and bilateral coronal (12) synostosis. All patients underwent fronto-orbital advancement or calvarial vault remodeling, or both. The average patient age at time of sagittal synostosis surgery was 13.4 months; unilateral coronal synostosis, 12.2 months; deformational plagiocephaly, 9.8 months; metopic synostosis, 8.6 months; and bilateral coronal synostosis, 10.4 months. Perioperative complications were minimal, with one mortality. Postoperative complications included three cases involving infection. The problem of reoperation for the removal of wires and plates remains the greatest postoperative complication. Because of poor patient compliance, no accurate postoperative follow-up has been recorded. On the basis of our experience, we wish to point out some problems inherent in this surgery and also the complications that can occur despite careful coordinated planning and team effort.

Bioabsorbable Fixation Devices

With time, more and more types of medical devices become available to assist the surgeon in managing patients. Bioabsorbable fixation devices, which have been directed toward the orthopedic surgeon over the past 10 years, are but one example. One aim of this article is to present the current status of bioabsorbable devices in medical practice to the craniomaxillofacial surgeon who may not be aware of the inroads this technology has made. A bioabsorbable fixation system has become available for use by the craniomaxillofacial surgeon, which is described. A further aim of this article is to present concisely the testing rigor required of such devices before their introduction to the U.S. market. This has the added benefit of explaining the important role of the surgeon in developing and helping reduce to standard clinical practice the use of new technologies.

Bioabsorbable plates and screws in pediatric craniofacial surgery: a review of 22 cases.

The purpose of this study was to evaluate the application of bioabsorbable fixation devices in reconstructive craniofacial procedures in the pediatric population. We reviewed 22 cases in which bioabsorbable plates and screws were used in craniofacial surgery for reconstruction. The procedures were performed in a 7-month period. The patients ranged in age from 5 to 228 months at the time of surgery (mean, 76.7 months). The postoperative clinical follow-up ranged from 2 to 16 weeks. The fixation devices were evaluated with regards to satisfactory fixation at the time of procedure. The postoperative follow-up evaluated clinical wound healing, signs of infection or local inflammation, and visibility or palpability of plates through the skin. All patients except one showed satisfactory wound healing with no sign of infection or local inflammation. The plates provided satisfactory fixation and were not visible through the skin. Two patients had plates that were palpable at the 4-month follow-up period. One patient with repair of a blow-out fracture of the orbit with resorbable mesh had redness and swelling over the wound site 2 weeks postoperatively with resolution 4 weeks postoperatively. Our early experience suggests reabsorbable fixation is an attractive option in pediatric plastic and craniofacial surgery. With further experience, this technology may represent the standard of care in reconstruction of the infant calvarium.

Austin/chevron osteotomy fixed with bioabsorbable poly- l-lactic acid single screw

The authors propose a new bioabsorbable fixation device to be applied to V-shaped transverse osteotomies of the head of the first metatarsal (Austin-chevron osteotomies) for hallux valgus surgery. Namely, a 3.3-mm. diameter cortical screw made of poly-L-lactic acid. This screw was applied in 30 patients with an average age of 44 years (range: 20 to 61). A total of 35 osteotomies was performed. The study refers to the period between 1992 and 1994 with a mean follow-up of 18 months (range: 12 to 36 months). The results of the study demonstrate good stability of the synthesis, with normal union (mean: 4 weeks), no adverse tissue reactions or osteolytic phenomena were noted. One patient developed avascular necrosis of the metatarsal head, which in the opinion of the authors, was not due to the device implanted. Over 90% of the patients were satisfied with both the aesthetic and functional results. The authors conclude that the poly-L-lactic acid cortical screw is a promising bioabsorbable fixation device for this corrective osteotomy in selected patients less than 50 years old, with good first metatarsal bone stock.

Arthroscopic bioabsorbable tack stabilization of initial anterior shoulder dislocations: A preliminary report

Twenty-six consecutive cadet athletes sustained an acute, initial anterior shoulder dislocation. All dislocations required a manual reduction for initial treatment. Arthroscopy was performed within 10 days in all patients. The Beach chair position and interscalene anesthesia were used in each case. At arthroscopy, 25 patients had an avulsion of the anterior-inferior capsulolabral complex (Bankart lesion) from the glenoid rim. One patient had a lateral detachment of the inferior glenohumeral ligament from the humeral neck. Twenty-three patients had a Hill-Sachs lesion and 3 SLAP tears were noted. All Bankart lesions were repaired with a cannulated bioabsorbable fixation device. Nineteen patients, over 1 year postoperative, are the subject of this preliminary report. The average age was 19.5 years (range, 17 to 23 years). Follow-up averaged 19 months (range, 12 to 24 months). The average loss of external rotation was 3 degrees. There have been no recurrent dislocations and 1 patient has had a single episode of resubluxation. Using the Rowe point score, 16 patients were rated excellent, 2 good, and 1 fair. All of the athletes in this study have returned to preinjury performance status. Acute stabilization of initial anterior shoulder dislocations appears to be an effective treatment option in young athletes known to have high recurrence rates with nonoperative treatment. This particular technique has been safe with little morbidity.

A Bioabsorbable Polymer for Collateral Ligament Repair in the Pig

SummaryA bioabsorbable internal fixation device of a poly-L-isomer of lactic acid (PLLA) was used to repair the proximal attachment of the medial femorotibial collateral ligament (MCL) in six miniature Yucatan pigs and compared with metal screw fixation in four pigs. Healing was evaluated by physical examination, gross dissection of surgical sites and histological evaluation of bone ligament interface. Chemical stress analysis of the tack was also evaluated.The absorbable PLLA tack induced minimal tissue reaction and maintained sufficient apposition for healing of the MCL in the miniature Yucatan pigs. No postsurgical complications were noted in the experimental or control groups. All surgical implant procedures were considered successful in maintaining MCL apposition. This study suggests future potential for utilization of the PLLA tack for bioabsorbable implants in soft tissue or bone.A bioabsorbable internal fixation device of a poly-L-isomer of lactic acid was used to repair the proximal attachment of the medial femorotibial collateral ligament in pigs, and compared with metal screw fixation. No postsurgical complications were noted in either group. All surgical implant procedures were successful. This study suggests future potential for utilization of the tack for bioabsorbable implants in soft tissue or bone.