Results of the Use of Bioabsorbable Magnesium Screws for Surgical Treatment of Mason Type II Radial Head Fractures.

Background: In Mason classification type II radial head fractures, compared to plate fixation, fixation with cannulated headless screws and absorbable pins has been reported to provide more favorable postoperative outcomes, including less postoperative limitation in range of motion. The fact that radial head fractures are less prone to weight-bearing during fracture union further supports the use of absorbable screws as a suitable alternative treatment option in radial head fractures. This study aimed to perform fixation through open reduction using bioabsorbable magnesium screws for Mason type II radial head fractures and to report radiographic and clinical results. Methods: Among patients who visited the orthopedic department from April 2017 to August 2021, 22 with surgical indications were selected for participation. Radiographic tests were conducted at 2 weeks, 4 weeks, 8 weeks, 12 weeks, 6 months, and over 1 year after surgery to confirm the degree of bone union, reduction loss, and degree of H2 gas production. The Disabilities of the Arm, Shoulder and Hand (DASH) score, Mayo Elbow Performance Score (MEPS), hand grip power, and range of joint motion were measured at the 6-month follow-up to evaluate the clinical efficacy of the operation. Results: Bone union was confirmed in all 22 cases, and the mean time to union was 10.2 weeks. DASH score was 22.27 on average and no patients complained of significant discomfort after the surgery. The mean MEPS was 91.1. The hand grip power of the affected hand was similar to that of the unaffected hand, being 1.19% weaker on average. These differences reached statistical significance (p = 0.002). The range of elbow joint motion was measured: mean flexion, 146.1°; mean extension, 1.4°; mean pronation, 88.2°; and mean supination, 87.9°. Conclusions: In treating Mason type II radial head fractures, the use of bioabsorbable screws made of magnesium showed satisfactory results in radiographic and clinical evaluations. Magnesium bioabsorbable screws can maintain sufficient stability at the fracture site and have the advantage of avoiding secondary operation for the removal of internal fixation devices.

Failure of osteochondral lesions using bioabsorbable fixation in the adolescent patient: a case report.

Injury to the chondral surface and subchondral bone can be due to osteochondritis dissecans or traumatic injury. These lesions can lead to pain, swelling, and mechanical symptoms causing functional impairments for patients. Treatment can include nonoperative management or surgical intervention including internal fixation. Internal fixation can be performed through multiple methods including the use of bioabsorbable screw fixation, though there is concern for potential early failure of this method. We present three cases of osteochondral lesions treated with internal fixation with bioabsorbable screws, which experienced early failure of the bioabsorbable screws, leading to failure of fixation and requiring revision surgery with advanced cartilage restoration procedures. All patients had resolution of their symptoms and improved function postoperatively. While the use of bioabsorbable screw fixation can potentially decrease cost and morbidity, their mechanical properties may increase the risk of failure before lesion healing. We advocate caution with the use of these screws for the treatment of unstable osteochondritis dissecans lesion and recommend careful patient selection and meticulous surgical technique to avoid failure of fixation of these lesions.

Fixation of intra-articular calcaneal fractures: A comparative study of the postoperative outcome between HA/PPLA screws and locking plates.

Background: Forged unsintered hydroxyapatite and poly l-lactic acid (F-u-HA/PLLA) screw is bioactivite, bioabsorbable, and radiopaque with high mechanical strength. Its efficacy has been previously demonstrated in the treatment of lateral humeral condylar, lateral tibial condylar, ankle, and patellar fractures. However, studies on its efficacy in treatment of calcaneal fractures is lacking. This study aimed to compare the postoperative results of F-u-HA/PLLA screw fixation and locking plate fixation for intra-articular calcaneal fractures. Methods: From January 2013 to December 2019, 47 closed intra-articular fractures treated with either F-u-HA/PLLA screws (group S, 18 feet in 17 patients) or locking plates (group P, 29 feet in 28 patients) in a single trauma center were retrospectively reviewed. The sinus tarsi approach was used in both groups. The time to bone union, step-off, varus deformity, Bohler's angle, and width and height of the calcaneus were assessed after surgery. Ankle joint range of motion (ROM) and postoperative complications were also assessed. Results: All fractures were successfully treated. The Kaplan-Meier curves of the two groups showed similar trends. The log-rank test showed no significant difference in the time to bone union between the two groups (p = 0.48). In the Cox proportional hazards model adjusted for preoperative width and Bohler's angle, the hazard ratio for bone union was not statistically significant (HR: 1.13, 95%CI: 0.50-2.56, p = 0.78). Other variables included step-off (group S: 2.0 vs group P: 2.2 mm, p = 0.84), varus deformity (2.0° vs. 3.0°, p = 0.7), Gissane's angle (103.5° vs 104.0°, p = 0.84), width (38.0 vs 34.8 mm, p = 0.12), height (42.1 vs 44.0 mm, p = 0.07), and ankle ROM degrees (dorsal flexion, 20.0° vs. 20.0°, p = 0.13; plantar flexion 40.0° vs 40.0°, p = 0.56), which were not significantly different between groups P and S. The Bohler's angle was smaller in group S than in group P (20.5° vs 27.0°, p < 0.01). No skin necrosis or infection was observed in either group. Conclusion: Postoperative results of F-u-HA/PLLA screw fixation using the sinus tarsi approach for intra-articular calcaneal fractures were as good as those of locking plate fixation.

Postoperative stability following a triple pelvic osteotomy is affected by implant configuration: a finite element analysis.

BACKGROUND: The triple pelvic osteotomy is an established surgical method with multiple modifications regarding surgical technique and choice of implant. The stability of the osteotomy is affected by numerous factors, and among these, the three-dimensional implant configuration is a scientifically less explored aspect. METHODS: We used a finite element model of a hemi-pelvis with a standardized triple osteotomy to calculate relative flexibility for loads in all translational degrees of freedom for five different implant configurations. Two of the configurations used entry points only feasible when implant removal was not necessary. RESULTS: The stability of the osteotomy improved with an increased distance between the implants in the plane of the osteotomy as well as for a more perpendicular angle relative to the osteotomy plane. The implant configurations with more entry points available made this easier to adhere to. CONCLUSION: The use of bioabsorbable implants may provide better opportunities for optimal implant constructs which can, to a certain degree, compensate for the lesser mechanical stiffness of bioabsorbable polymers as compared to metal implants.

Biomechanical comparison between bioabsorbable and medical titanium screws in distal chevron osteotomy of first metatarsal in hallux valgus treatment.

Polylactic acid (PLA) composite materials have been used for manufacturing surgical internal fixations owing to their satisfactory mechanical strength and absorbability. This, in turn, reduces the pain and risks associated with the secondary operation on patients. Although the mechanical properties of bioabsorbable materials have been considerably enhanced via modifications and optimization, the strength and stiffness of these materials are considerably inferior to those of metals. Therefore, whether PLA fixation can satisfy the required mechanical properties has been a consistent subject of interest in clinical practice. In this study, the mechanical properties of PLA bioabsorbable (Changchun SinoBiomaterials Co., Ltd., China) and titanium hollow screws (Shanghai Carefix Medical Instrument Co., Ltd., China) were compared in hallux valgus surgery with chevron osteotomy. Three-dimensionally printed osteotomy guides were used for cutting the artificial first metatarsal model (SKU3422, Sawbones) to reduce the errors due to the variations in individual bone densities and osteotomy angles; the cut parts were subsequently fixed with the PLA and titanium alloy screws. A digital image correlation system was used to obtain the full-field strain of the specimen to evaluate the mechanical behaviors under static and fatigue loads. The experimental results demonstrated that, by designing a reasonable osteotomy angle, the compressive strength of the specimen with PLA screws under chevron osteotomy can be as high as that of the specimen with titanium screws. Moreover, their stiffness can reach up to 60%-90% that of titanium screws. After 240,000 cycles of compression, the PLA screws maintained their strength and stiffness. These bioabsorbable fixtures can effectively prevent stress shielding under a suitable osteotomy. Hence, as an optimal substitute for metal fixtures, an increase in clinical applications to surgery is anticipated, along with progressive in-depth research on the biomechanical properties of bioabsorbable materials.

Methods of Tibiofibular Syndesmosis Fixation.

The tibiofibular syndesmosis is a ligamentous structure connecting the distal ends of the tibia and fibula. This article presents and compares the available methods of treatment of syndesmosis injuries. Current publications from the online database PubMed and relevant available books are analysed and compared with AO Surgery guidelines. Metal and bioabsorbable syndesmotic screws and the suture button technique, including all possible modifications of these approaches, are compared. The focus is on the technical aspects of the procedures, functional outcomes and complications of these procedures. According to the literature, the best long-term functional outcomes are obtained with the dynamic fixation method involving the suture button. This fixation technique is closest to a physiological connection, there is no need to subsequently remove the implant and return to work is faster. Given all this, the popularity of this fixation technique can be expected to increase dynamically.

Matched retrospective analysis of three different fixation devices for chevron osteotomy.

Chevron osteotomy with consecutive fixation is a commonly performed operative treatment option for hallux valgus deformities. The present retrospective study aims to compare the clinical and radiological outcome of novel bioabsorbable magnesium screw fixation with metal screw and Kirschner wire fixation. Eighteen matched triplets were assembled according to the following criteria: female gender, age difference less than 5 years, date of operation within 4 months, difference in preoperative intermetatarsal angle less than 5°, and equal experience of the first and second surgeon. These patients, between 18 and 85 years of age and with a minimum follow-up period of 12 months, were invited to a follow-up examination, of which only 16 matched triplets of patients entirely kept the appointment. Thus, 48 feet of 44 patients were clinically evaluated using the American Orthopaedic Foot & Ankle Society scale, Foot Function Index, University of California and Los Angeles Activity Score, as well as a visual analogue scale for pain, satisfaction, cosmetic results, and functional impairment. Radiographical assessment included measuring intermetatarsal angle and first metatarsophalangeal angles. All occurring complications and revision surgeries were noted. Significant differences were observed for postoperative intermetatarsal angle between magnesium screw and pin fixation (p = 0.009). Moreover, patients receiving magnesium screw were significantly more prone to undergo the same procedure again (p = 0.03). In conclusion, if the advantages of bioabsorbable magnesium screws outweigh the drawbacks of increased costs and a higher surgical demand, this implant might serve as possible chevron osteotomy fixation method. Compression screws and Kirschner wires also show comparable satisfactory outcomes. LEVEL OF EVIDENCE: III retrospective comparative study.

Surgical Repair of a Unicortical Condylar Fracture in a Thoroughbred Racehorse Using a Bioabsorbable Screw.

Surgical repair of unicortical fractures of the distal condyles of the third metacarpal/metatarsal bones (MCIII/MTIII) has been described. In the present case, a bioabsorbable screw was used to stabilize a unicortical fracture in the palmar aspect of the medial condyle of MCIII in a National Hunt Thoroughbred racehorse. The clinical, radiographic, and magnetic resonance imaging findings before and after surgery were recorded. Eighteen weeks after surgery, the lameness had resolved and the bone surrounding the fracture had recovered its normal architecture. One year after surgery, the horse was in training, showed no recurrence of the primary lesion and was considered a "racing prospect" by the trainer. The use of a bioabsorbable screw in this case was associated with a successful outcome and is worthy of further investigation.

Pediatric tibial eminence fracture treatment: A case series using a bioabsorbable screw.

BACKGROUND: Pediatric tibial eminence fractures constitute a complex injury with multiple treatment options. We have described a technique that combines direct visualization through an open approach and stable fixation using a bioabsorbable screw. The purpose of this study is to describe our surgical technique for tibial eminence fractures and to compare the radiographic and functional outcomes to previous open or arthroscopic methods. METHODS: We retrospectively reviewed a series of five pediatric patients who underwent open reduction and internal fixation of a tibial eminence fracture with a headless, bioabsorbable poly-L lactic acid (PLLA) screw (Bio-Compression screw, Arthrex Inc, Naples, FL) from 2016 to 2017. The surgical technique involves an open approach, direct fracture reduction, and fixation with a PLLA screw without violating the epiphyseal plate. Postoperative assessment was quantified using the Lysholm knee score (LKS), knee arc of motion (AOM), presence of a pivot shift or Lachman, and knee radiographs with an average of 18.4 months of follow-up. RESULTS: Five patients (average age of 11.3 years) were treated with a biobsorbable screw and followed for an average of 18.4 months. Average LKS was 99.6, AOM was 98.4%, all patients had negative pivot shift and Lachman exams, and all patients went on to radiographic union. No patients required re-operation or implant removal. CONCLUSIONS: The goals of tibial eminence fracture management are fracture union, restoring knee stability, and regaining normal knee motion and kinematics. Our study demonstrates that open treatment with a bioabsorbable screw is an excellent alternative surgical method as it reliably results in rigid fixation, fracture union, excellent knee function scores, and it mitigates the possible need for hardware removal. LEVEL OF EVIDENCE: Therapeutic Level IV - Case series.

Clinical Evidence for Treatment of Distal Tibiofibular Syndesmosis Injury: A Systematic Review of Clinical Studies.

No consensus had been reached about the optimal treatment for syndesmotic fixation. We performed a review of randomized controlled trials (RCTs) to assist in clarifying many of the controversies that were debated for years despite new technology and options. PubMed, Embase, and the Cochrane Library were searched through specific terms and limits. Only RCTs were selected for final inclusion. Study screening and data extraction were performed independently by 2 reviewers. Thirteen RCTs, including 828 cases, met the inclusion criteria and are summarized in this review. Pooled results demonstrated that dynamic fixation had better functional outcomes as well as lower rates of malreduction and complications compared with syndesmotic screw fixation. Both absorbable screw and tricortical screw fixation showed similar results to quadricortical metallic screws. Therefore, dynamic fixation is recommended for the treatment of syndesmosis injuries.

Anterior cruciate ligament reconstruction is associated with greater tibial tunnel widening when using a bioabsorbable screw compared to an all-inside technique with suspensory fixation.

PURPOSE: To compare clinical outcomes and tunnel widening following anterior cruciate ligament reconstruction (ACLR) performed with an all-inside technique (Group A) or with a bioabsorbable tibial screw and suspensory femoral fixation (Group B). METHODS: Tunnel widening was assessed using computed tomography (CT) and a previously validated analytical best fit cylinder technique at approximately 1-year following ACLR. Clinical follow-up comprised evaluation with IKDC, KSS, Tegner, Lysholm scores, and knee laxity assessment. RESULTS: The study population comprised 22 patients in each group with a median clinical follow-up of 24 months (range 21-27 months). The median duration between ACLR and CT was 13 months (range 12-14 months). There were no significant differences in clinical outcome measures between groups. There were no differences between groups with respect to femoral tunnel widening. However, there was a significantly larger increase in tibial tunnel widening, at the middle portion, in Group B (2.4 ± 1.5 mm) compared to Group A (0.8 ± 0.4 mm) (p = 0.027), and also at the articular portion in Group B (1.5 ± 0.8 mm) compared to Group A (0.8 ± 0.8 mm) (p = 0.027). CONCLUSION: Tibial tunnel widening after ACLR using hamstring tendon autograft is significantly greater with suspensory femoral fixation and a bioabsorbable tibial interference screw when compared to an all-inside technique at a median follow-up of 2 years. The clinical relevance of this work lies in the rebuttal of concerns arising from biomechanical studies regarding the possibility of increased tunnel widening with an all-inside technique. LEVEL OF EVIDENCE: III.

Isolated Lateral Malleolar Fracture Treated with a Bioabsorbable Magnesium Compression Screw.

Magnesium (Mg) bioabsorbable screws are new biomaterials used in fracture fixation. In the current literature, there is only one case report on the use of magnesium bio-absorbable screws in ankle fractures. Within the present study, a 19-year-old female who sustained an isolated lateral malleolar fracture was treated with open reduction and intramedullary Mg screw fixation and then followed up for two years. Fracture union was achieved without any complication such as failure of fixation, loss of reduction, infection, or any other adverse reaction. Mg bioabsorbable screws are an alternative method of fracture fixation as compared to conventional metallic implants since they eliminate the need for implant removal.

Fixation of Small Osteochondral Fragments in a Comminuted Distal Humerus Fracture with Magnesium Bioabsorbable Screws: A Case Report.

The treatment of comminuted distal humeral fractures with free osteochondral fragments is challenging. Osteochondral fragments should be retained whenever possible and secured with implants buried beneath the articular surface to obtain a uniform articular surface. Headless compression screws and K wires are commonly used for this purpose. However, certain complications have been reported with these fixation implants in case of the non-union and osteolysis of the fragments such as migration and cartilage damage. Fixation of osteochondral fractures in distal humeral fractures using bioabsorbable implants has been rarely reported in the current literature. Herein, a patient who sustained a comminuted distal humeral fracture with multi-fragmentary osteochondral fragments is presented, and treatment with magnesium bioabsorbable compression screws is discussed.

Quiste sinovial en la tibia luego de la reconstrucción del ligamento cruzado anterior: evaluación de 14 pacientes / Synovial cyst in the tibia after reconstruction of the anterior cruciate ligament: evaluation of 14 patients

Introducción: La aparición de quiste sinovial pretibial posterior a cirugía de reconstrucción de LCA es una complicaciónpoco frecuente, de origen multifactorial que puede suceder incluso años luego de la cirugía. El objetivo del presentetrabajo fue analizar una serie de pacientes tratados por esta complicación. Material y métodos: Se evaluaron retrospectivamente 14 pacientes operados de resección de quiste pretibial posterior auna cirugia de LCA entre el año 2008 y 2016. Se analizó el tipo de injerto, técnica quirúrgica e implante utilizado, la clínicadel paciente y el tiempo de aparición de los síntomas. Se realizó una evaluación radiológica pre y post operatoria. Sedescribió la cirugía de resección del quiste y la anatomía patológica. Evaluamos el índice de recidiva. Resultados: Nueve hombres y 5 mujeres con edad promedio de 38 años. El seguimiento promedio fue de 35 meses.Todos operados con isquiotibiales cuádruple y técnica trans-tibial. El tiempo promedio entre la cirugía de LCA y aparicióndel quiste fue de 29 meses. Clínicamente presentaban una tumoración entre 1.1 y 3 cm sin signos de inestabilidad. Através de Rx y RM se evidenció ensanchamiento del túnel tibial en todos los casos. Se rellenó el túnel tibial con injertoóseo en 7 casos. La anatomía patológica informó: 12 quistes sinoviales (5 asociados a remanentes de sutura) y 2 casosúnicamente fibrosis. Un paciente evolucionó con recidiva...

Introduction: Among complications following ACL reconstruction, the formation of a pre-tibial cyst in the site of the tibialtunnel is very rare and might happen even years after surgery. The purpose of this study was to analyze 14 patients with tibialsynovial cyst after ACL reconstruction.Material and method: We retrospectively evaluated patients operated between 2008 and 2016. We analyzed the graftselection and surgical technique for ACL reconstruction, the time between primary surgery and the onset of symptoms andthe clinical presentation. A pre and postoperative radiological evaluation was performed for every patient. Surgical techniquefor cyst excision, histological analysis and culture results were also analyzed. The recurrence rate was evaluated at finalfollow-upResults: Nine patients were male, with an average age of 38 years. The average follow-up was of 35 months. All ACLreconstructions were performed using hamstring graft and a trans-tibial technique. The average time between primary ACLsurgery and onset of the cyst was 29 months. All patients presented a palpable tumor at proximal tibia and a stable knee.The cyst size varied between 1.1 and 3 cm. In all cases, Rx and MRI could appreciate a widening of the tibial tunnel. Thetibial tunnels were filled with cancellous bone in 7 cases. Pathological anatomy reported 12 synovial cysts (5 associated withremaining suture) and 2 fibrosis. One recurrence was reported...

Bioabsorbable Screws Used in Hallux Valgus Treatment Using Proximal Chevron Osteotomy / 대한족부족관절학회지

Hallux valgus is a deformity that causes pain in the first metatarsophalangeal joint. Surgical methods are quite diverse and a range of osteotomies are used at the proximal and distal part of the metatarsal bone and proximal phalange. Fixation methods, such as plate, screw, K-wire, and others have been used in various ways. The fixation device is often removed with various side effects due to the fixation devices. In the case of instruments that are absorbed in vivo, these procedures are not necessary to remove and there is an advantage of not performing the second operation. Three patients were treated, in which a proximal chevron osteotomy was used with a bioabsorbable screw (K-MET™; U&I Corporation).

Femoral and Tibial Tunnel Diameter and Bioabsorbable Screw Findings After Double-Bundle ACL Reconstruction in 5-Year Clinical and MRI Follow-up.

BACKGROUND: Tunnel enlargement is frequently seen in short-term follow-up after anterior cruciate ligament reconstruction (ACLR). According to new evidence, tunnel enlargement may be followed by tunnel narrowing, but the long-term evolution of the tunnels is currently unknown. HYPOTHESIS/PURPOSE: The hypothesis was that tunnel enlargement is followed by tunnel narrowing caused by ossification as seen in follow-up using magnetic resonance imaging (MRI). The purpose of this study was to evaluate the ossification pattern of the tunnels, the communication of the 2 femoral and 2 tibial tunnels, and screw absorption findings in MRI. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirty-one patients underwent anatomic double-bundle ACLR with hamstring grafts and bioabsorbable interference screw fixation and were followed with MRI and clinical evaluation at 2 and 5 years postoperatively. RESULTS: The mean tunnel enlargement at 2 years was 58% and reduced to 46% at 5 years. Tunnel ossification resulted in evenly narrowed tunnels in 44%, in conical tunnels in 48%, and fully ossified tunnels in 8%. Tunnel communication increased from 13% to 23% in the femur and from 19% to 23% in the tibia between 2 and 5 years and was not associated with knee laxity. At 5 years, 54% of the screws were not visible, with 35% of the screws replaced by a cyst and 19% fully ossified. Tunnel cysts were not associated with worse patient-reported outcomes or knee laxity. Patients with a tibial anteromedial tunnel cyst had higher Lysholm scores than patients without a cyst (93 and 84, P = .03). CONCLUSION: Tunnel enlargement was followed by tunnel narrowing in 5-year follow-up after double-bundle ACLR. Tunnel communication and tunnel cysts were frequent MRI findings and not associated with adverse clinical evaluation results.

Fijación de tórax inestable con placas y tornillos bioabsorbibles. Presentación de serie de casos / Thoracic inestability fixed with bioabsorbable screws and plates

Resumen: Antecedentes: El tórax inestable se trata con ventilación mecánica o inhaloterapia y analgesia. Poco se ha publicado sobre el uso de material bioabsorbible y su evolución en la fijación de tórax inestable. Métodos: Estudio descriptivo de pacientes con tórax inestable sometidos a fijación con placas y tornillos bioabsorbibles en un período comprendido de Febrero de 2009 a Diciembre de 2011. Resultados: Presentamos 18 casos con edades entre 33 y 74 años (media de 53), tres con tórax inestable bilateral; la fijación costal se realizó entre 1 y 21 días del accidente (media de 1.5). Se inició deambulación al día siguiente en 14 casos; la estancia postoperatoria fue de cuatro días (rango de 3 a 14). La frecuencia cardíaca de los pacientes previa a la cirugía era de 90 por minuto (rango 82 a 100) y bajó a 84 después de la fijación (rango 82 a 92); la frecuencia respiratoria preoperatoria era 26 por minuto (rango 22 a 28) y bajó a 22 por minuto (rango 20 a 26) en el postoperatorio. Conclusiones: El uso de material bioabsorbible para osteosíntesis costal no tiene efectos secundarios atribuibles al material en el corto plazo.

Abstract: Background: Flail chest is managed with mechanical ventilation or inhaloteraphy and analgesia. Little has been published on the use of bioabsorbable material and its evolution in flail chest fixation. Methods: This is a descriptive study of patients with unstable chest undergoing fixation with bioabsorbable plates and screws in a period from February 2009 to December 2011. Results: We report 18 cases, aged 33-74 years (mean 53), three with bilateral involvement; rib fixation was performed between 1-21 days of the accident (mean 1.5). They started walking the next day in 14 cases; postoperative stay was four days (range 3-14). The heart rate of patients prior to surgery was 90 per minute (range 82-100) and lowered to 84 after fixation (range 82-92), preoperative respiratory rate was 26 per minute (range 22-28) and below 22 per minute (range 20 to 26) in postoperative period. Conclusions: The use of bioabsorbable material for osteosynthesis of costal fractures did not show side effects in our period of study.

Application of bioabsorbable screw fixation for anterior cervical decompression and bone grafting

OBJECTIVES: To examine the application of bioabsorbable screws for anterior cervical decompression and bone grafting fixation and to study their clinical effects in the treatment of cervical spondylosis. METHODS: From March 2007 to September 2012, 56 patients, 36 males and 20 females (38-79 years old, average 58.3±9.47 years), underwent a novel operation. Grafts were fixed by bioabsorbable screws (PLLA, 2.7 mm in diameter) after anterior decompression. The bioabsorbable screws were inserted from the midline of the graft bone to the bone surface of the upper and lower vertebrae at 45 degree angles. Patients were evaluated post-operatively to observe the improvement of symptoms and evaluate the fusion of the bone. The Japanese Orthopaedic Association (JOA) score was used to evaluate the recovery of neurological functions. RESULTS: All screws were successfully inserted, with no broken screws. The rate of symptom improvement was 87.5%. All of the grafts fused well with no extrusion. The average time for graft fusion was 3.8±0.55 months (range 3-5 months). Three-dimensional reconstruction of CT scans demonstrated that the grafts fused with adjacent vertebrae well and that the screws were absorbed as predicted. The MRI findings showed that the cerebrospinal fluid was unobstructed. No obvious complications appeared in any of the follow-up evaluations. CONCLUSIONS: Cervical spondylosis with one- or two-level involvement can be effectively treated by anterior decompression and bone grafting with bioabsorbable screw fixation. This operative method is safe and can avoid the complications induced by metal implants.

The Natural History of Biointerference Screw Cyst and New Bone Formation in Anterior Cruciate Ligament Reconstruction: 16-Year Follow-up.

BACKGROUND: A variety of fixation devices are available for anterior cruciate ligament reconstruction (ACLR). Bioabsorbable screws allow imaging postoperatively without image artefact, as with magnetic resonance imaging (MRI). There is also the perceived benefit of screw resorption and subsequent host tunnel bone ingrowth. PURPOSE/HYPOTHESIS: The purpose of this study was to document the natural history of poly L-lactic acid (PLLA) bioabsorbable interference screws. Manufacturers claimed that screws would be resorbed and replaced by new bone within 2 years. The hypothesis was that these screws take considerably longer to achieve this claim. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Ten consecutive patients undergoing routine ACLR with a PLLA bioabsorbable RCI screw (Arthrex) and a standard 4-strand hamstring graft technique were assessed via MRI and telephone questionnaire at 1, 2, 4, 7, 10, and 16 years postoperatively. RESULTS: At 4-year follow-up, no resorption of the screw or bone formation had occurred. At 7-year follow-up, absorption of 7 screws was complete, cyst formation had occurred in 3 patients, and 5 patients had new bone formation. At 10-year follow-up, all screws were reabsorbed, cyst formation was evident in only 2 cases, and 7 patients had evidence of new bone formation. At 16-year follow-up, cyst formation was only present in 1 patient, and all patients had evidence of new bone formation. All patients had an intact anterior cruciate ligament and had returned to preinjury sporting activity. CONCLUSION: PLLA bioabsorbable screws take longer to resorb than previously thought by the manufacturers (ie, 2 years). New bone formation is evident in 100% of patients by 16 years. Cyst formation does not occur in all patients with a bioabsorbable screw implant. In the 3 patients demonstrating the presence of a cyst, no associated adverse effects were found with regard to anterior cruciate ligament graft survival or instability.

[Thoracic inestability fixed with bioabsorbable screws and plates]. / Fijación de tórax inestable con placas y tornillos bioabsorbibles. Presentación de serie de casos.

BACKGROUND: Flail chest is managed with mechanical ventilation or inhaloteraphy and analgesia. Little has been published on the use of bioabsorbable material and its evolution in flail chest fixation. METHODS: This is a descriptive study of patients with unstable chest undergoing fixation with bioabsorbable plates and screws in a period from February 2009 to December 2011. RESULTS: We report 18 cases, aged 33-74 years (mean 53), three with bilateral involvement; rib fixation was performed between 1-21 days of the accident (mean 1.5). They started walking the next day in 14 cases; postoperative stay was four days (range 3-14). The heart rate of patients prior to surgery was 90 per minute (range 82-100) and lowered to 84 after fixation (range 82-92), preoperative respiratory rate was 26 per minute (range 22-28) and below 22 per minute (range 20 to 26) in postoperative period. CONCLUSIONS: The use of bioabsorbable material for osteosynthesis of costal fractures did not show side effects in our period of study.

ANTECEDENTES: El tórax inestable se trata con ventilación mecánica o inhaloterapia y analgesia. Poco se ha publicado sobre el uso de material bioabsorbible y su evolución en la fijación de tórax inestable. MÉTODOS: Estudio descriptivo de pacientes con tórax inestable sometidos a fijación con placas y tornillos bioabsorbibles en un período comprendido de Febrero de 2009 a Diciembre de 2011. RESULTADOS: Presentamos 18 casos con edades entre 33 y 74 años (media de 53), tres con tórax inestable bilateral; la fijación costal se realizó entre 1 y 21 días del accidente (media de 1.5). Se inició deambulación al día siguiente en 14 casos; la estancia postoperatoria fue de cuatro días (rango de 3 a 14). La frecuencia cardíaca de los pacientes previa a la cirugía era de 90 por minuto (rango 82 a 100) y bajó a 84 después de la fijación (rango 82 a 92); la frecuencia respiratoria preoperatoria era 26 por minuto (rango 22 a 28) y bajó a 22 por minuto (rango 20 a 26) en el postoperatorio. CONCLUSIONES: El uso de material bioabsorbible para osteosíntesis costal no tiene efectos secundarios atribuibles al material en el corto plazo.