Bioresorbable Pins Research Articles

Comparison of biodegradable and metallic tension-band fixation for paediatric lateral condyle fracture of the elbow

IntroductionIn our retrospective study we compared the outcomes of paediatric lateral condyle fractures of the elbow fixed by bioabsorbable pins and tension-band sutures or by metallic tension-band with K-wires. Materials and methodsWe reviewed the data of children operated on for lateral condyle fractures between 2010 and 2020. Patients were classified as follows: 1. fractures treated with metallic (KW group), 2. fractures treated with resorbable implants (BR group). We compared the distribution of age, sex and fracture type in each group. Operative times of the two techniques were also recorded and compared. We analysed the X-rays taken one year after the injury and measured the following parameters: presence of possible non-union, varus or valgus deviation, lateral spur formation. Patients whose follow-up period was less than one year were excluded. For categorical data, group comparisons were performed with Chi-square test or Fisher's exact test, depending on the sample size. The evaluation of discrete variables was performed with Mann-Whitney U test. Results42 patients met the above criteria. We found 19 children in the Kirschner -wire + tansion band wire (KW) group and 23 in the Bioresorbable pin + tension band suture (BR) group. There were no significant differences between the study groups in terms of age, sex, left-right ratio, number of complications, operation time, number of Jacobs II and III cases or follow-up time. The operation time was on average 5 min longer in the bioresorbable group (K-wire mean = 62.1 min, Bioresorbable mean = 67 min), this difference, however, is not statistically significant (P = 0.177). In terms of minor and major complications, there was no statistically significant difference between the two groups. (P = 0.729). ConclusionsWe did not notice any difference between the complication rates of the two methods, so the real advantage of the absorbable implant technique is that no second intervention is necessary.The benefits of using biodegradable implants in various osteosynthesis techniques need further confirmation by randomised trials.

Radiographic and complication evaluation of 2 different bioresorbable pins in hallux valgus corrective surgery.

Osteotomies to correct hallux valgus are usually secured using metal implants. Their main disadvantage is the need for a repeat surgery for removal of implanted material. Bioresorbable implants would make it possible to overcome this complication. Few studies analyse the results of using bioresorbable pins. The primary objective of this study is to compare hallux valgus correction radiographic results with the use of two types of bioresorbable pins. The secondary objectives are to screen for possible complications related to the use of these bioresorbable pins. This is a descriptive, retrospective, single-centre study carried out between May 2018 and May 2022 in the orthopaedic surgery department of the Centre Chirurgical Emile Gallé at the CHRU in Nancy (France). The study involved 105 hallux valgus (98 patients) operated on by open double metatarsal and phalangeal osteotomy. Osteotomies were stabilised with resorbable polylactic acid (PLLA) pins (Arthrex® TRIM-IT® drill pin) in 57 cases (53 patients), and with resorbable polylactic acid-polyglycolic acid copolymer (PGLA) pins (Bioretec® ActivaPins®) in 48 cases (45 patients). The efficacy of hallux valgus correction was analysed in terms of changes in preoperative and postoperative radiographic parameters at 1 and 6 months on a weight-bearing foot. Descriptive statistics were used to describe the demographic and radiological parameters of each group. The mean age was 59.7 years (range 25-81 years) in the PLLA group and 56 years (range 23-78 years) in the PGLA group. The mean preoperative HVA was 30° (range 15-63°) in the PLLA group and 30.8° (range 15-57°) in the PGLA group. The mean preoperative IMA was 14.4° (range 7-30°) in the PLLA group and 13.8° (range 7-20°) in the PGLA group. There was a statistically significant correction of hallux valgus in the PLLA (p=5.24 X 10-15 ) and PGLA (p=3.56 X 10-13 ) groups. The mean correction for the hallux valgus angle was 13° in the PLLA group and 12° in the PGLA group. There was no statistically significant difference in hallux valgus correction between the PLLA and PGLA groups, particularly in terms of hallux valgus severity. There was no radiological or clinical complication in the groups related to bioresorbable pins. The use of bioresorbable pins allows effective stabilisation of osteotomies to correct hallux valgus. There was no significant difference in correction between PLLA and PGLA implants, regardless of the severity of the hallux valgus. We did not observe any obvious clinical or radiological complications related to their use. The use of bioresorbable osteosynthesis material in forefoot surgery seems to offer interesting advantages, providing patients with safer and less invasive treatment solutions.

Sternal closure with sandwiched three-piece bioresorbable mesh reduces postoperative hemorrhage: a retrospective study

BackgroundMedian sternotomy is the most performed procedure in cardiac surgery; however, sternal displacement and bleeding remains a problem. This study aimed to investigate whether sternal reconstruction using a sandwiched three-piece bioresorbable mesh plate can prevent postoperative sternal displacement and bleeding more than a bioresorbable pin.MethodsPatients (n = 218) who underwent median sternotomy were classified according to whether a sandwiched three-piece bioresorbable mesh plate and wire cerclage (group M, n = 109) or a bioresorbable pin and wire cerclage (group P, n = 109) were used during sternal reconstruction. The causes of postoperative sternal displacement and bleeding with computed tomography data were analyzed and compared between the groups.ResultsThe preoperative patient characteristics did not significantly differ between the groups. However, the evaluation of sternal and substernal hematoma on postoperative day 5 using computed tomography showed sternal displacement in 4 (4%) and 22 (20%) patients, and substernal hematoma in 17 (16%) and 41 (38%) patients in groups M and P, respectively; this difference was significant. Furthermore, the amount of bleeding at 6 h postoperatively was lower in group M than in group P (235 ± 147 vs. 284 ± 175 mL, p = 0.0275). Chest reopening, intubation time, and length of intensive care unit and hospital stays did not differ between the groups. The evaluation of substernal hematoma based on computed tomography yielded a significantly lower for group M than for group P, revealing that the mesh plate was an independent predictor of substernal hematoma prevention.ConclusionSternal fixation with a three-piece bioresorbable mesh plate could prevent postoperative sternal displacement, bleeding, and substernal hematoma more than sternal fixation with a pin.

Evaluation of surgical fixation methods for the implantation of melt electrowriting-reinforced hyaluronic acid hydrogel composites in porcine cartilage defects.

The surgical repair of articular cartilage remains an ongoing challenge in orthopedics. Tissue engineering is a promising approach to treat cartilage defects; however, scaffolds must (i) possess the requisite material properties to support neocartilage formation, (ii) exhibit sufficient mechanical integrity for handling during implantation, and (iii) be reliably fixed within cartilage defects during surgery. In this study, we demonstrate the reinforcement of soft norbornene-modified hyaluronic acid (NorHA) hydrogels via the melt electrowriting (MEW) of polycaprolactone to fabricate composite scaffolds that support encapsulated porcine mesenchymal stromal cell (pMSC, three donors) chondrogenesis and cartilage formation and exhibit mechanical properties suitable for handling during implantation. Thereafter, acellular MEW-NorHA composites or MEW-NorHA composites with encapsulated pMSCs and precultured for 28 days were implanted in full-thickness cartilage defects in porcine knees using either bioresorbable pins or fibrin glue to assess surgical fixation methods. Fixation of composites with either biodegradable pins or fibrin glue ensured implant retention in most cases (80%); however, defects treated with pinned composites exhibited more subchondral bone remodeling and inferior cartilage repair, as evidenced by micro-computed tomography (micro-CT) and safranin O/fast green staining, respectively, when compared to defects treated with glued composites. Interestingly, no differences in repair tissue were observed between acellular and cellularized implants. Additional work is required to assess the full potential of these scaffolds for cartilage repair. However, these results suggest that future approaches for cartilage repair with MEW-reinforced hydrogels should be carefully evaluated with regard to their fixation approach for construct retention and surrounding cartilage tissue damage.

Revision of Failed Osteochondritis dissecans Surgical Treatment: Case Report.

Osteochondritis dissecans (OD) is one of the most common cartilage lesions of the knee. Conservative treatment is recommended if the lesions are stable with no loose bodies or there are open physes. Surgical intervention is recommended as the primary treatment in symptomatic adults with unstable chondral lesions or with concomitant loose bodies. We describe a case of a patient suffering from OD with a bone lesion in the weight-bearing area of medial femoral condyle. Arthroscopy was performed and an osteochondral fragment from the medial femoral condyle was observed and two articular loose bodies were removed. After months, the patient returned with pain and a locked knee. magnetic resonance imaging (MRI) presented a new unstable chondral flap at the posterior border of the previous lesion. Surgery was performed again, and at open examination, the previous OD lesions were covered by regenerative tissue, with a lesion of 3cm2 at the inferior medial part of the chondral flap. The peripheral margins were cleaned, and a subchondral crater was curetted. The subchondral lesion was debrided, and the flap was fixed with pins and a central bioresorbable screws. Revision surgery with fixation of the chondral flap using bioresorbable pins and screws led to satisfactory results. Open revision surgery allowed us a more accurate assessment of the OD area to provide an effective fixation of the chondral flap and in this circumstance, this should have been done after seeing the first MRI.

Large Glenoid Defects Treated by Multiple Bioresorbable Pinning-Assisted Bone-Grafting in Reverse Shoulder Arthroplasty.

This procedure is performed with the patient under general anesthesia and in the beach-chair position, via a deltopectoral approach. After placing the structural graft, 5 to 10 provisional 1.5-mm Kirschner wires are inserted through the graft up the medal cortical bone of the scapula. The Kirschner wires are subsequently replaced with bioresorbable (BR) pins (1.5-mm Fixsorb Pin; TEIJIN). If more wires are needed, another set of 4 to 5 RB pins is inserted to gain initial stability. After placing the graft, the glenoid component is implanted as usual. Traditionally, 1 or 2 screws are inserted in the periphery of the graft to obtain stability. The screws either must be inserted at an angle that does not impede placement of the implant2 or are removed before the placement of the glenoid implant. One or a maximum of 2 long screws are inserted through the graft and glenoid3, meaning that the screw(s) must be aimed at a very narrow space between the central post and screws. Otherwise, these screws will represent an obstacle to the placement of the glenoid implant. In addition to facilitating initial graft stability, this procedure promotes graft incorporation. Typically, when performing this procedure, a total of 15 to 20 temporary Kirschner wires are placed in sets, with 5 to 7 wires per set. Of these, the most stable wires, usually 8 to 10 in total, are replaced by BR pins. The resultant bone holes, whether filled or unfilled with the BR pins, may promote neovascularization and osteoinduction, enabling long-lasting remodeling of and improved incorporation of the bone graft. A prior study compared the use of MBP versus angulated bony-increased offset (BIO) graft, assessing graft incorporation according to the size of the remaining graft on axial radiographs, with full incorporation defined as >75% of the original graft size1,2. In that study, all 13 patients in the MBP group showed full graft incorporation compared with only 9 (47%) of 19 patients in the angulated BIO group (p < 0.001)1. Expose all 4 quadrants of the glenoid in cases of type-2 deformity. Accurate orientation of the MBP is important.Expose the upper and lower 2 quadrants of the glenoid in cases of type-3 deformity. The bases of the scapular spine and axillary border serve as a graft scaffold.Preserve circumferential soft tissues in cases of type-3 deformity because these tissues will serve to contain cancellous bone graft.Keep the Kirschner wire that extends the most medially (reaching the most medial cortical bone of the scapula) as a future guidewire for drilling of the central peg hole. RSA = reverse shoulder arthroplastyMBP = multiple bioresorbable pinningBIO = bony-increased offsetBR = bioresorbableTSA = total shoulder arthroplastyCT = computed tomographyK-wire = Kirschner wireROM = range of motionP.O. = postoperative.

A Sequential Approach to the Management of Posterior Glenoid Defects in RSA: Angulated BIO Versus Multiple Bioresorbable Pinning-Assisted Structural Bone-Grafting.

Background:Large posterior glenoid defects pose problems in reverse shoulder arthroplasty (RSA). We have adopted a sequential approach to the management of posterior glenoid defects using asymmetrical reaming, the placement of a ring graft around the central peg (bony-increased offset, or BIO), or structural bone-grafting, depending on the amount of glenoid retroversion. Furthermore, we have devised multiple bioresorbable pinning (MBP)-assisted bone-grafting, in which as many bioresorbable pins as required are inserted, from whichever aspects of the graft necessary, to achieve initial stability.Methods:We reviewed 52 shoulders with posterior glenoid defects undergoing RSA between 2014 and 2019 (mean follow-up, 4.8 years; range, 2 to 6 years). Twenty (38.5%) of the shoulders had glenoid retroversion of <15° and were treated by asymmetrical reaming (Group A), 19 (36.5%) of the shoulders had retroversion of ≥15° to <30° and were treated with asymmetrical reaming combined with angulated ring graft around the central peg (Group B), and 13 (25.0%) of the shoulders had retroversion of ≥30° and were treated with MBP-assisted bone-grafting (Group C).Results:Mean version correction was 10.6° ± 4.3° in Group A, 20.7° ± 8.8° in Group B, and 33.8° ± 9.6° in Group C. The mean postoperative active anterior elevation was 138.3° ± 12.3°, 128.3° ± 12.3°, and 126.5° ± 15.3° in the 3 groups, respectively. The mean postoperative Constant score was 66.8 ± 14.6, 62.2 ± 13.5, and 61.7 ± 16.7, respectively. The mean preoperative active anterior elevation was significantly higher in Group A than in Group C (p = 0.037). The full or partial graft-incorporation rate (≥25% of original size) was 89.5% in Group B and 100% in Group C. One glenoid fracture and 1 case of transient brachial plexus palsy occurred in Group B (10.5%), and 1 acromion fracture and 2 cases of transient brachial plexus palsy occurred in Group C (23.1%).Conclusions:The results of the present sequential approach to management of posterior glenoid defects by the 3 modalities were acceptable. The present MBP-assisted bone-grafting procedure is an effective treatment for cases of shoulder arthropathy with severe posterior glenoid defects. Angulated ring grafting around the central peg may yield equally acceptable results, although its graft-incorporation rate requires further follow-up.Level of Evidence:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Resorbable Pins to Enhance Scaffold Retention in a Porcine Chondral Defect Model.

Cartilage repair strategies have seen improvement in recent years, especially with the use of scaffolds that serve as a template for cartilage formation. However, current fixation strategies are inconsistent with regards to retention, may be technically challenging, or may damage adjacent tissues or the implant itself. Therefore, the goal of this study was to evaluate the retention and repair potential of cartilage scaffolds fixed with an easy-to-implement bioresorbable pin. Electrospun hyaluronic acid scaffolds were implanted into trochlear groove defects in 3 juvenile and 3 adult pigs to evaluate short-term retention (2 weeks; pin fixation vs. press-fit and fibrin fixation) and long-term repair (8 months; scaffold vs. microfracture), respectively. For the retention study, press-fit and fibrin fixation resulted in short-term scaffold dislodgment (n = 2 each), whereas pin fixation retained all scaffolds that were implanted (n = 6). Pin fixation did not cause any damage to the opposing patellar surface, and only minor changes in the subchondral bone were observed. For long-term repair, no differences were observed between microfracture and scaffold groups, in terms of second-look arthroscopy and indentation testing. On closer visualization with micro computed tomography and histology, a high degree of variability was observed between animals with regard to subchondral bone changes and cartilage repair quality, yet each Scaffold repair displayed similar properties to its matched microfracture control. In this study, pin fixation did not cause adverse events in either the short- or the long-term relative to controls, indicating that pin fixation successfully retained scaffolds within defects without inhibiting repair.

Optimized Design and Development of a Bioresorbable High Rotational Stability Fixation System for Small Bone Fragments

Bioresorbable pins are experiencing a growing interest and a likewise increasing use in orthopedic surgery for bone fixation. Indeed, such devices are naturally degraded by the human body and a subsequent surgery for their removal is not needed. However, bioresorption has a remarkable side effect on the performance of the devices, since mechanical properties decay over time. This aspect is essential for bone healing. In the first 60 days, the pin must bear continuous mechanical stress while preventing torsional slip of bone fragments. Although torsional support can be improved with suitable pin section design, degradation kinetics and the consequent loss in mechanical stability are slowed down while using high molecular weight polymers, whose slow bioresorption increases recovery time and negatively affects patient care. Herein, a bioresorbable pin of new conception, in terms of cross‐sectional shape and material formulation, is presented. Both section and polymer design are optimized through comprehensive mathematical modeling, which synergistically combines degradation and mechanical loads. As a result of the model, bioresorption time is minimized, whereas adequate mechanical resistance is ensured for the first 60 days. The most promising device is then injection molded, sterilized, mechanically tested, and successfully evaluated ex vivo in human femoral heads.

A comparative biomechanical evaluation of different osteosynthesis techniques used for intracapsular condylar head fractures

PurposeThe aim of the present experimental study was to evaluate the biomechanical behavior in different types of osteosynthesis (titanium screws, bioresorbable pins and miniplates) used in management of intracapsular condylar head fractures. MethodExperimental models of the condylar head fractures were simulated on 15 dry human cadaveric mandibles. Osteotomized mandibles were randomly divided into three groups with different fixation systems used: 1) 15 mm long titanium screws, 2) 15 mm long bioresorbable pins Sonic Pins Rx, 3) T-shaped titanium miniplate and 7 mm long titanium screws. Mandibles were loaded in TIRAtest testing machine (Germany). The main types of deformations, including torsion, bending and shearing, were simulated to study the biomechanical characteristics of the fixation systems. ResultsTitanium bicortical screws demonstrated the highest stiffness in standard loading conditions. The fixation with bioresorbable pins showed lower stiffness in both frontal and sagittal loads. This is indicative of the fact that resorbable pins, which have numerous advantages for clinical usage, cannot provide adequately stable fixation in maximal masticatory loads. The mandibles fixed with T-shaped plate had the lowest stiffness. ConclusionScrew or pin fixation, regardless of the material used, was not resistant to rotational loads. On the contrary, the stiffness of T-shaped plates was quite significant. In real clinical conditions, if rotational displacements are not effectively compensated by irregularities in the fracture surface and precise repositioning of the bone fragments, combined use of miniplates and bicortical titanium screws or two screws can be beneficial.

Clinical Study on Percutaneous Intramedullary Bioresorbable Pin Fixation for Fourth and Fifth Metacarpal Bone Fracture

Clinical Study on Percutaneous Intramedullary Bioresorbable Pin Fixation for Fourth and Fifth Metacarpal Bone Fracture

Biomechanical evaluation of novel ultrasound-activated bioresorbable pins for the treatment of osteochondral fractures compared to established methods.

Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed. The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins. In a biomechanical laboratory setting, osteochondral fragments of the medial femoral condyle of sheep were refixated with ultrasound-activated pins [US fused poly(L-lactide-co-D,L-lactide) (PLDLLA) pins], polydioxanone (PDA) pins and conventional titanium screws. Anchoring forces of the different fixation methods were examined, registered and compared concerning shear force and tensile force. Concerning the pull out test, the US fused PLDLLA pins and titanium screws (~122 N and ~203 N) showed comparable good results, while the PDA pins showed significantly lower anchoring forces (~18 N). Examination of shear forces showed a significantly higher anchoring of the screws (~248 N) than the US fused PLDLLA pins (~218 N). Nevertheless, the US fused PLDLLA pins could significantly outperform the PDA pins (~68 N) concerning shear forces. The US fused PLDLLA pins demonstrated a comparable anchorage to the fixation with screws, but were free from the disadvantages of metal implants, i.e. the need for implant removal. The PDA pin application showed inferior biomechanical properties.

Traumatic isolated osteochondral fractures of medial femoral condyle treated with multiple retrograde Kirschner wires – A simple cost-effective technique

Management of osteochondral fractures of the knee is very crucial to prevent early onset osteoarthritis in young adults. Currently, fixation by biodegradable screws, bioresorbable pins or meniscus arrows can be expensive and also carries risk of complications, such as synovitis and osteonecrosis. In a developing country such as India, there is a need of cost-effective, safe and reproducible treatment option to fix these kinds of fractures. We report the results in 11 patients (seven males and four females) with mean age of 28.09 years, with isolated traumatic osteochondral fracture of medial femoral condyle that was treated between June 2011 and May 2015 with multiple Kirschner wires (K wires). Mean time interval between injury and surgery was 4 days (range, 2–6 days). Through medial parapatellar arthrotomy, the fragment was fixed to its corresponding bed in the medial femoral condyle in a retrograde manner with multiple non-parallel K wires (1.6–2.5mm). K wires were first drilled through the reduced fragment, the medial femoral condyle and out through the skin on medial side of knee and distal thigh while ensuring through the arthrotomy site that the intra-articular tips of the wires were flush or just buried below the cartilaginous surface of the fragment. Mean time of the union was 8.5 weeks and full range of motion was achieved by 11 weeks. Mean follow-up was 54 weeks (range, 40–64 weeks). Clinical outcomes were found to be excellent in all the patients. Mean IKDC score was 94.9, mean Lysholm score was 94.8 and mean Likert score was 4.63 (range, 4–5) indicating a high level of satisfaction. None of the patients developed any major complications. In third world countries with limited resources, multiple K wires are a safe, reproducible and relatively inexpensive method of treating these complex joint injuries in young adults.

Influencing factors and complications in open treatment of acute anterior glenoid rim fractures

The aim of this comparative study was to evaluate the clinical radiological outcome after open treatment of acute anterior glenoid rim fractures and to analyze the influencing factors and complications. The study included 26 patients with an average age of 51.6 years (range 27-71 years) at surgery. The mean period of follow-up was 5.1 years (range 2.0-11.1 years). The average extent of glenoid fracture involvement was 25.5 % (range 18-35%) and three fixation techniques were applied: 1) bioresorbable pins (n = 16), 2) small fragment screws (n = 5) and 3) bioresorbable suture anchors (n = 5). The mean score values were 80.3 points for the absolute Constant score, 87.6 points for the normalized Constant score, 88.7 points for the Rowe score, 17.4 points for the Oxford shoulder score, 10.3 points for the simple shoulder test, 13.0 points for the shoulder pain and disability index and 81.5 % for the subjective shoulder value. The fixation technique did not show a significant influence; however, multi-fragment fractures were associated with a significantly inferior absolute (73 vs. 87 points, p = 0.022) and normalized Constant scores (81 vs. 94 points, p = 0.019). Subscapularis insufficiency with internal rotation deficit was found in 10 (39 %) patients and posttraumatic osteoarthritis occurred in 6 (23 %) patients. Open fixation yielded good or excellent shoulder function in 20 out of the 26 (77 %) patients and the clinical outcome primarily depended on the underlying type of fracture. Significantly inferior outcomes should be expected in patients with multi-fragment fractures. The main complications were subscapularis insufficiency and posttraumatic osteoarthritis.

Osteosynthese zentraler Talusfrakturen

Anatomic reduction of talar neck and body fractures with axial realignment and restoration of the articular surfaces of the talus. Displaced talar neck and body fractures. High perioperative risk, soft tissue infection, neurogenic osteoarthropathy. Reduction of the axial alignment of the talus and its joints via bilateral approaches according to the preoperative CT-based planning. A medial malleolar osteotomy may be necessary to approach the talar dome. The blood supply via the deltoid ligament and the sinus tarsi has to be respected. Manipulation of the main fragments with K-wires introduced temporarily; a mini-distractor is helpful in restoring the length. Internal fixation is tailored to the individual fracture pattern, including conventional and headless screws, bioresorbable pins, lost K-wires, and/or minifragment plates. Joint transfixation for 6 weeks to ensure ligamentous healing if instability persists after internal fixation. With severe soft tissue damage, temporary tibiometatarsal external fixation is applied until soft tissue consolidation. Range of motion exercises of the ankle and subtalar joints starting postoperative day 2 except for cases with joint transfixation. Partial weight bearing of 20 kg for 10-12 weeks. Use of a cast or walker for 6 weeks followed by intensive active and passive range of motion exercises of the ankle and subtalar joints. Over 8 years 79 fractures of the talar neck and body were treated. In all, 43 patients with 45 talar neck (n = 30) and body (n = 15) fractures were re-examined clinically and radiologically (mean follow-up 3 years). Definite treatment consisted of open reduction and screw fixation of the talus in 41 cases and small plate fixation in 2 cases supplemented by temporary external fixation for 1-3 weeks in 12 cases. At follow-up, the Maryland Foot Score averaged 86.1 and the AOFAS Ankle/Hindfoot Score averaged 78.9. The Hawkins classification was of prognostic value in talar neck fractures. The functional results and the rate of avascular necrosis (AVN) were unaffected by the time to definite internal fixation. AVN was observed in 11 cases (24%); with only partial AVN involving less than one third of the talar body in 8 of these patients. Due to complete AVN with collapse of the talar dome, 3 patients (6.7%) required fusion. Signs of posttraumatic arthritis of the tibiotalar or subtalar joint were seen in 21 cases (47%). The rate of symptomatic posttraumatic arthritis correlated with the occurrence of total AVN, but not with partial AVN.

Refixation of osteochondral fractures by ultrasound-activated, resorbable pins

ObjectivesOsteochondral injuries, if not treated adequately, often lead to severe osteoarthritis. Possible treatment options include refixation of the fragment or replacement therapies such as Pridie drilling, microfracture or osteochondral grafts, all of which have certain disadvantages. Only refixation of the fragment can produce a smooth and resilient joint surface. The aim of this study was the evaluation of an ultrasound-activated bioresorbable pin for the refixation of osteochondral fragments under physiological conditions.MethodsIn 16 Merino sheep, specific osteochondral fragments of the medial femoral condyle were produced and refixed with one of conventional bioresorbable pins, titanium screws or ultrasound-activated pins. Macro- and microscopic scoring was undertaken after three months. ResultsThe healing ratio with ultrasound-activated pins was higher than with conventional pins. No negative heat effect on cartilage has been shown.ConclusionAs the material is bioresorbable, no further surgery is required to remove the implant. MRI imaging is not compromised, as it is with implanted screws. The use of bioresorbable pins using ultrasound is a promising technology for the refixation of osteochondral fractures.

The combination of microfracture and a cell-free polymer-based implant immersed with autologous serum for cartilage defect coverage

The purpose of this short-term pilot study was to determine the clinical and MRI outcome of a combination of microfracture with a cell-free polymer-based matrix for the treatment of cartilage defects in the knee. The technique was used for treatment of symptomatic cartilage defects in the knee. Five patients were prospectively evaluated during 2 years with use of the Knee injury and Osteoarthritis Outcome Score (KOOS), the Tegner activity scale and the visual analog scale (VAS). MRI data were analyzed based on the original and modified MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) scoring system at 6, 12 and 24 months of follow-up. A gradual clinical improvement was observed during the follow-up. Adverse reactions to the matrix were not observed. The scaffold was firmly fixed with the use of bioresorbable pins. Both MOCART scoring systems revealed no significant deterioration or improvement in the repair tissue during the follow-up period. However, the majority of the patients exhibited subchondral lamina and bone changes. The formation of an intralesional osteophyte was observed in one case. The key finding in this study was that this procedure is safe for the treatment of cartilage defects in the knee. The patients showed a gradual clinical improvement postoperatively. Sixty percent (3/5) of the defects were adequately (complete or hypertrophic) filled with repair tissue at 2 years of follow-up. IV.

A biomimetic artificial intervertebral disc system composed of a cubic three-dimensional fabric

Background context In the quest for clinically functional artificial intervertebral discs (AIDs), multidisciplinary technologies have been employed. Existing solid mobile AIDs essentially consist of the superposition of solid plates and core materials; however, it is thought that an ideal surgical AID technology has not yet been developed. To overcome the limitation of these existing AIDs, we developed a unique flexible AID disc system on the basis of our original biomimetic concept. The AID is composed of a cubic three-dimensional fabric (3DF) with a triaxial fiber alignment, which offers biomimetic long-term dynamic mechanical behavior along with durability. Purpose This article substantiates the potential clinical use of the 3DF disc system that quite differs from existing ones. Study design We designed the lumbar and cervical 3DF discs that improved the structural weaknesses caused by the collagenous fiber alignment of biological intervertebral disc. Bioresorbable hydroxyapatite particles were deposited on the surface layer of the 3DF disc to promote new bony ingrowth and to ensure secure binding at the interface of the contacting vertebral bodies. A stand-alone system was devised for surgical reliability in terms of both positioning and fixation, allowing tight press fitting with the vertebral bodies. Bioactive and bioresorbable pins were penetrated through the 3DF disc body and projected from the surface to allow ideal insertion and fixation to the disc space, preserving the precise position during dynamical movement. In vitro endurance of the 3DF disc was examined under long-term alternating stresses, and the in vivo animal tests were conducted in the intervertebral lumbar discs at L5–L6 excised from baboons and replaced with the lumbar 3DF disc. Methods The static mechanical endurance was assessed through a creep test. In vitro endurance of the 3DF disc under repetitive stresses including axial compressing, flexion-extension, torsional twisting, and lateral bending were applied to the 3DF disc for a long-term for up to 105 million stresses, which is roughly equivalent to exposure of natural biological movement for more than 50 years. In the animal test, eight baboons were euthanized 6 months postoperatively. To their extracted spines, six pure moments (flexion and extension, left and right lateral bending, and left and right torsion) were applied vertically to the superior end of the specimen and then values of range of motions (ROMs) were calculated. Histological analyses were conducted on 12 reticuloendothelial and systemic tissues. Results The 3DF disc retained its biomimetic “J-shaped” stress-strain behavior without generating wear debris for up to 105 million stresses. A 130-N loading for the creep test decreased the height of 0.3 mm during 80 to 1,000 hours. In the biomechanical test, ROM values of axial rotation and flexion-extension showed no significant difference from the intact excluding that of lateral bending because the location of each pin to stand alone certainly controlled the bending behavior only. The histological analysis indicated no significant pathologic changes induced by the 3DF disc. Conclusions The 3DF disc system is clinically suitable for human disc replacement arthroplasty based on the findings of long-term durability with dynamic motion in vitro and effective animal tests in vivo. This system surely overcomes the limitations of existing solid AIDs, and the clinical potential of the biomimetic 3DF discs has been verified. This new biomaterial technology delivers most of the functions and characteristics required by a clinically available AID if applied correctly by surgeons.

Bioresorbable Pins and Interference Screws for Fixation of Hamstring Tendon Grafts in Anterior Cruciate Ligament Reconstruction Surgery

Background Biodegradable cross-pins have been shown to provide higher failure loads than do screws for fixation of hamstring tendons under laboratory conditions. Purpose To compare the clinical results of biodegradable pins (RigidFix) and interference screws (BioCryl) for fixation of hamstring grafts in arthroscopically assisted anterior cruciate ligament reconstruction. Study Design Randomized controlled trial; Level of evidence, 1. Methods To test the hypothesis of a difference of 1.0 ± 1.2 mm in anterior knee laxity between the two fixation options, 54 patients were randomly assigned to groups via a block randomization scheme and sealed envelopes. All patients underwent standardized hamstring graft reconstruction and had similar postoperative aftercare by an accelerated rehabilitation protocol. Measures assessed at baseline and after 1 and 2 years of follow-up included (1) the side-to-side difference in anterior laxity (KT-1000 arthrometer), (2) Short Form 36 physical and mental component scores, and (3) the International Knee Documentation Committee form scores. Results After 1 and 2 years, 26 and 21 patients in the BioCryl group and 28 and 24 patients in the RigidFix group were available for follow-up examination. No significant difference was noted in instrumented anterior translation between BioCryl and RigidFix fixation: 1 year, 0.11 (95% CI, —0.60 to 0.82; P = .7537); 2 years, 0.33 (95% CI, —0.43 to 1.08 mm; P = .3849). Also, there were no significant differences in the mean physical and mental component scores and International Knee Documentation Committee form scores and in overall complication and surgical revision rates. A pin dislocation was classified as the sole procedure-specific serious adverse event. Conclusion Bioresorbable pins do not provide better clinical results than do resorbable interference screws for hamstring graft fixation in anterior cruciate ligament reconstruction surgery.

Arthrodesis of the distal interphalangeal joint: description of a new technique and clinical follow-up at 2 years

Arthrodesis of the distal interphalangeal joint (DIPJ) is an accepted operative procedure to treat osteoarthritis, instability and joint deformity. There is a wide spectrum of recommended operative techniques including cerclage wires, headless screws, bio-resorbable pins and lag screws. Lag screw fixation remains one of the most accepted methods of fixation; however, problems can occur in particular subsidence of the screw head leading to loss of compression and prominence of the screw head in the finger tip necessitating removal. We describe here a new technique of DIPJ arthrodesis that avoids these problems. The technique is described here in detail, and clinical results are given for 18 joints (17 patients) followed-up at a mean 24 months (range 6-44). Mean post-operative DASH score was 15. There were no cases of non-union; only four complications were seen, one case of nail growth disturbance and one of early screw breakage necessitating revision. Two infections necessitated early hardware removal although both arthodesis were united. The technique is simple and reliable giving consistent clinical results.