Secondary intra-articular dislocation of a broken bioabsorbable interference screw after anterior cruciate ligament reconstruction

[Effectiveness comparison between Scarf osteotomy combined with Akin osteotomy fixed by absorbable screws and fixed by metal screws for the treatment of moderate to severe hallux valgus]

Objective

To evaluate the effectiveness of Scarf osteotomy combined with Akin osteotomy in the treatment of moderate to severe hallux valgus with absorbable screws or metal screws fixation by clinical and radiological data.

Methods

Between March 2014 and May 2016, the Scarf osteotomy combined with Akin osteotomy was used to treat 62 patients (83 feet) with moderate to severe hallux valgus. Twenty-five patients (35 feet) were fixed by absorbable screws (group A) and 37 patients (48 feet) were fixed by metal screws (group B). The difference in gender, age, affected side, etiology, severity, disease duration, preoperative hallux valgus angle (HVA) and first-second intermetatarsal angle (1-2IMA) measured in weight-bearing anteroposterior X-ray film, preoperative American Orthopaedic Foot and Ankle Society (AOFAS) scores and visual analogue scale (VAS) scores between 2 groups ( P>0.05). The complications and healing time of 2 groups were recorded and compared. At last follow-up, the AOFAS and VAS scores, and HVA, 1-2IMA measured by weight-bearing anteroposterior X-ray film were used to evaluate the effectiveness.

Results

All incisions healed by first intention and no incision-related complication occurred in the two groups after operation. Both groups were followed up, the follow-up time in group A was 12-36 months (mean, 24.4 months) and in group B was 14-38 months (mean, 25.7 months). In group A, 1 foot was complicated with hallux varus, 2 feet had mild stiffness, 1 foot appeared metastatic metatarsal pain, and in group B was 2, 3, 2 feet, respectively. There was no recurrence of hallux valgus in both groups. The difference in the incidence of complications between the two groups after the first operation was not significant ( χ ²=0.275, P=0.843). The removal rate of internal fixator in group B was 89.2% (33 cases) during the second operation, among which 3 cases had screw slip and 1 case had screw fracture. And 10.8% (4 cases) refused the second removal operation due to their age. Postoperative X-ray films showed that both groups had good healing at the osteotomy site, and there was no significant difference in healing time between the two groups ( t=1.633, P=0.285). At last follow-up, the AOFAS score, VAS score, HVA, and 1-2IMA were significantly improved in the two groups when compared with preoperative ones ( P<0.05); but no significant difference was found between the two groups ( P>0.05).

Conclusion

The effectiveness of Scarf osteotomy combined with Akin osteotomy in the treatment of moderate to severe hallux valgus is significant, with few complications. Compared with being fixed by metal screws, being fixed by absorbable screws has the same effectiveness, but can avoid the risk of second operation to remove the internal fixator.

Effectiveness of Headless Bioabsorbable Screws for Fixation of the Scarf Osteotomy

BACKGROUND

Scarf osteotomy has been used in hallux valgus surgery due to its large fixation surface for screws and low postoperative complications. However, screws may cause skin irritation from their head, which may require an additional surgical procedure to remove.

METHODS

This study included 115 patients (106 females and 9 males, 115 feet) who underwent hallux valgus correction with a scarf osteotomy using bioabsorbable screws between September 2010 and September 2012. Preoperative and postoperative 1-month and 1-year radiographic measurements, including intermetatarsal angle (IMA), hallux valgus angle (HVA), distal metatarsal articular angle (DMAA), proximal phalangeal articular angle (PPAA), and lateral translational distance (LTD), were obtained. American Orthopaedic Foot & Ankle Society (AOFAS) hallux/forefoot scores were used for patient satisfaction.

RESULTS

Preoperative mean values of HVA, IMA, and PPA of 32.8 degrees, 14.6 degrees, and 7.52 degrees, respectively, improved to 10.7 degrees, 6.0 degrees, and 4.6 degrees, respectively at 1-year follow up (P < .05). The difference in LTD between the 1-month and 1-year follow-up was not statistically significant. AOFAS hallux/forefoot score improved from 69.1 to 96.1 at the 1-year follow up (P < .001). Complete screw absorption was not seen radiographically. Sixteen feet had complications reported. One patient complained of skin irritation over a small protrusion of the screw, and another patient had a foreign body reaction. There were 3 patients with neurologic injury from a popliteal block and 3 patients with dorsal cutaneous nerve symptoms. Four feet had metatarsal fracture during surgery.

CONCLUSION

We found the scarf osteotomy using bioabsorbable screws to have satisfactory clinical and radiographic results with a low complication rate.

LEVEL OF EVIDENCE

Level IV, case series.

Severe cartilage damage from a broken absorbable screw head after fixation of an avulsion fracture of the tibial attachment of the posterior cruciate ligament: A case report

INTRODUCTION

The use of bioabsorbable interference screws has become popular for treatment of avulsion fractures of the posterior cruciate ligament (PCL). Complications are uncommon. We report a case of severe chondral damage caused by the early breakage of an absorbable screw head after fixation of an avulsion fracture of the tibial attachment of the PCL. The patient felt a sudden locking of the knee when getting off a car at 4 months after the PCL surgery. MRI revealed intraarticular migration of the head of the interference screw. During revision surgery, the broken part was removed without incident, and severe cartilage damage was observed. The patient experienced a complete resolution of symptoms at the 6-month follow-up.

CONCLUSION

MRI examination is recommended in case of sudden locking of the knee for patients undergoing PCL fixation with bioabsorbable interference screws. Surgical treatment should be performed immediately when screw breakage was confirmed.

High-purity magnesium interference screws promote fibrocartilaginous entheses regeneration in the anterior cruciate ligament reconstruction rabbit model via accumulation of BMP-2 and VEGF

Interference screw in the fixation of autologous tendon graft to the bone tunnel is widely accepted for the reconstruction of anterior cruciate ligament (ACL), but the regeneration of fibrocartilaginous entheses could hardly be achieved with the traditional interference screw. In the present work, biodegradable high-purity magnesium (HP Mg) showed good cytocompatibility and promoted the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF), fibrocartilage markers (Aggrecan, COL2A1 and SOX-9), and glycosaminoglycan (GAG) production in vitro. The HP Mg screw was applied to fix the semitendinosus autograft to the femoral tunnel in a rabbit model of ACL reconstruction with titanium (Ti) screw as the control. The femur-tendon graft-tibia complex was retrieved at 3, 6, 9 and 12 weeks. Gross observation and range of motion (ROM) of the animal model reached normal levels at 12 weeks. No sign of host reaction was found in the X-ray scanning. The HP Mg group was comparable to the Ti group with respect to biomechanical properties of the reconstructed ACL, and the ultimate load to failure and stiffness increased 12 weeks after surgery. In the histological analysis, the HP Mg group formed distinct fibrocartilage transition zones at the tendon-bone interface 12 weeks after surgery, whereas a disorganized fibrocartilage layer was found in the Ti group. In the immunohistochemical analysis, highly positive staining of BMP-2, VEGF and the specific receptor for BMP-2 (BMPR1A) was shown at the tendon-bone interface of the HP Mg group compared with the Ti group. Furthermore, the HP Mg group had significantly higher expression of BMP-2 and VEGF than the Ti group in the early phase of tendon-bone healing, followed by enhanced expression of fibrocartilage markers and GAG production. Therefore we proposed that the stimulation of BMP-2 and VEGF by Mg ions was responsible for the fibrochondrogenesis of Mg materials. HP Mg was promising as a biodegradable interference screw with the potential to promote fibrocartilaginous entheses regeneration in ACL reconstruction.

Bioabsorbable interference screw failure in anterior cruciate ligament reconstruction: A case series and review of the literature

BACKGROUND

To report a case series of failures of bioabsorbable interference screws with possible identification of a novel failure mechanism.

METHODS

A retrospective review of ACL reconstructions by the senior author utilizing BioComposite™ Interference Screws (Arthrex, Inc., Naples, FL) was performed. Complications related to screw placement, including fracture, breakage or bending were examined. Our rate and methods of failure were compared to those quoted in the current literature.

RESULTS

Eighty-seven patients of average age 23.8 years met inclusion criteria. There were eight screw failures in six patients, with femoral failure in seven and tibial failure in one. The femoral screw fractured halfway between the tip and head in five, while the head of the screw broke in one and the screw bent in another. In the case of tibial interference screw fracture, failure occurred halfway between the tip and head. The insertion device that was used was replaced after recognition of material deformation and considered a potential contributor to the breakage risk as no further screw failures have occurred since.

CONCLUSIONS

We demonstrate a unique failure mechanism of bio-absorbable interference screws. In each case, the reconstruction was salvaged. Regular inspection of materials and implants can ensure optimal outcomes and decrease complications intra-operatively.

Bioabsorbable versus metallic interference screws in anterior cruciate ligament reconstruction: a systematic review of overlapping meta-analyses

PURPOSE

Multiple meta-analyses of randomized controlled trials have been conducted to compare clinical and functional outcomes after anterior cruciate ligament (ACL) reconstruction using metallic interference screw (MIS) versus bioabsorbable interference screw (BIS) fixation, but discrepancies in their findings have prevented a consensus conclusion. The purposes of this study were (1) to conduct a systematic review of meta-analyses comparing MISs and BISs in ACL reconstruction, (2) to provide surgical treatment recommendations for ACL graft fixation based on the highest available evidence, and (3) to propose future research avenues in areas of practice lacking high-level evidence.

METHODS

The literature was systematically reviewed to identify meta-analyses comparing MISs and BISs in ACL reconstruction. Data were extracted for clinical and functional outcomes, and methodologic quality was assessed using the validated Quality of Reporting of Meta-analyses and Oxman-Guyatt systems. To determine which meta-analyses provided the current best available evidence, the Jadad decision algorithm was used.

RESULTS

One Level I and 2 Level II meta-analyses were included. None showed differences between BISs and MISs in validated outcome scores, pivot-shift testing, KT arthrometry (MEDmetric, San Diego, CA), or loss of knee motion. Subgroup analyses found no differences in clinical outcomes or knee stability across biomaterials. All meta-analyses were of high quality according to the Quality of Reporting of Meta-analyses and Oxman-Guyatt systems. Two meta-analyses were determined by the Jadad algorithm to represent the current best available evidence. Both studies showed prolonged knee effusion with BIS use, with 1 also showing an increased incidence of femoral tunnel widening and screw breakage with BIS use.

CONCLUSIONS

Whereas clinical and functional outcomes are similar with MISs and BISs, prolonged knee effusion, femoral tunnel widening, and screw breakage are more common with BIS use. Future cost-effectiveness analyses may help weigh the known advantages of BISs against their costs and adverse-event profile.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

High strength chitosan rod prepared via LiOH/urea solvent through centrifugation induced orientation processing

High strength chitosan rod prepared via LiOH/urea solvent utilizing the unique centrifugation induced orientation method.

Biodegradation of a magnesium alloy implant in the intercondylar femoral notch showed an appropriate response to the synovial membrane in a rabbit model in vivo

Degradable magnesium alloys are promising biomaterials for orthopedic applications. The aim of this study was to evaluate the potential effects on both the synovial membrane (synovialis) and the synovial fluid (synovia) of the degradation products of a MgYREZr-pin implanted in the intercondylar femoral notch in a rabbit model. Thirty-six animals were randomized into two groups (MgYREZr or Ti6Al4V alloy) of 18 animals each. Each group was then divided into three subgroups with implantation periods of 1, 4, and 12 weeks, with six animals in each subgroup. The initial inflammatory reaction caused by the surgical trauma declined after 12 weeks of implantation, and elucidated a progressive recovery of the synovial membrane. Compared with control Ti6Al4V pins, there were no significant differences between the groups. However, after 12 weeks, recovery of the synovial membrane was more advanced in the titanium group, in which 92% showed no signs of synovitis, than in the magnesium group. A cytotoxicity test with L929 cells and human osteoblasts (HOB) was also conducted, according to EN ISO 10993-5/12, and no toxic leachable products were observed after 24 h of incubation. In conclusion, the MgYREZr alloy seems to be a suitable material for intra-articular degradable implants.

Meta-analysis comparing bioabsorbable versus metal interference screw for adverse and clinical outcomes in anterior cruciate ligament reconstruction

PURPOSE

To compare bioabsorbable screw (BS) against metal screw (MS) primarily on adverse effects and secondarily on clinical outcomes after single-bundle primary anterior cruciate ligament reconstruction.

METHODS

Electronic searches were performed using search strategies meeting the mentioned purposes. Retrieved articles were selected for randomised controlled trials (RCTs) reporting at least 1-year follow-up. Potential studies were selected under inclusion and exclusion criteria. Risk of biases and data extraction was completed by two review authors. Discrepancies were resolved through discussion. Mean difference and risk ratio with 95 % confidence interval (CI) were used for continuous and binary outcomes, respectively. Heterogeneity was assessed using I (2). Pooled treatment effects with 95 % CI were estimated using the fixed- or random-effect model where appropriate.

RESULTS

Eleven RCTs with 878 randomly allocated patients were included, and 711 patients (81 %) with eligible follow-up time up to 8 years were analysed. Comparing with the MS group, BS group using medial hamstring graft showed evidence of larger tunnel widening on the femoral side measured from radiographs or magnetic resonance imaging, though data could not be pooled because diverse measurement methods had been used. Significantly higher rates of effusion and screw breakage, and fewer cases of complete tunnel healing were reported in the BS group. Nevertheless, functional and clinical results were not deteriorated by the presence of these adverse effects for both short- and longer-term follow-ups.

CONCLUSION

This is the first systematic review focusing on adverse effects of the BS, such as larger tunnel widening and higher rates of other complications. With these effects, routine use of the BS should be balanced with the advantages claimed. Cost-effectiveness is another issue, and well-designed RCTs are needed to better validate the implication.

An Automatic Three-Dimensional Evaluation of Screw Placement After Anterior Cruciate Ligament Reconstruction Using MDCT Images

A metallic interference screw, which is a fixation device used in anterior cruciate ligament (ACL) reconstruction, is important for fixing the grafts to the tibia. Loosening of fixation sometimes happens because the screw is displaced time passes, which results in instability of the knee. It is therefore important to analyze screw displacement highly accurately. The purpose of this study is to propose an evaluation of screw displacement in MDCT imaging of the knee after ACL reconstruction. Clinical experiments used 22 MDCT images that are not displaced in the clinical sense. Results of simulation experiments show that error was 0.14 mm, which was less thanMDCT image resolution. This study concluded that the proposed method useful in evaluating two MDCT images at different time points.

Migration of "bioabsorbable" screws in ACL repair. How much do we know? A systematic review

PURPOSE

Although bioabsorbable screws promise to degrade within months up to several years after implantation, often this does not happen. In fact, other problems such as screw breakage, tunnel enlargement, allergic or foreign body reactions, cyst or abscess formation, and delayed migration of "biodegradable" screws have been reported. This study aims to provide relevant basic science knowledge and recent insights concerning "biomaterials" currently used in fixation devices for anterior cruciate ligament (ACL) repair. A systematic review on the topic of screw "migration" is provided.

METHODS

A PubMed search combining all the key terms was done looking for complications related to late migration of "bioabsorbable" screws used in ACL reconstruction without inferior time limitation up to January 2012. Only clinical reports were included. Reference lists of reports were checked to detect others not identified by the original search. A pre-publication search was performed to identify the most recent relevant articles.

RESULTS

A total of ten articles referred to migration of "bioabsorbable" interference screws. Most cases reported on poly-L-lactic acid-based screws. Migration was noticed between 3 and 22 months postoperatively. It was noticed both in the tibia and the femur and with the application of several types of graft.

CONCLUSION

Migration is a possible complication of "bioabsorbable" interference screws. The information related to all clinical implications of the so-called "biodegradable screws" remains scarce and probably suffers from the phenomenon of publication bias. The complexity of possible reactions occurring in the human body is difficult to reproduce under controlled laboratory conditions.

Complications after tendon transfers in the foot and ankle using bioabsorbable screws

BACKGROUND

Tendon transfers are commonly used for correction of pathology or deformity of the foot and ankle. Bioabsorbable implants have been developed as an alternative to metal interference screws. The purpose of this study was to document complications following tendon transfers of the foot and ankle using bioabsorbable poly-L-lactide interference screws.

METHODS

A retrospective chart review was used to identify patients in whom either of the 2 senior authors had performed a tendon transfer of the foot and ankle using a bioabsorbable interference screw between 1999 and 2005. A minimum of 6 months of follow-up was required for inclusion in the study. In all, 31 patients were identified who met the inclusion criteria with an average follow-up of 75 weeks. All screws were made of poly-L-lactide (PLLA).

RESULTS

Complications were identified in 12 (39%) of patients. All of the complications reported were known complications of the tendon transfer procedure itself, and were not directly related to the bioabsorbable screw.

CONCLUSIONS

Based on these early results, PLLA implants appear safe and effective for tendon transfers of the foot and ankle. However, until long-term outcomes are available, judicious use of these implants is recommended.

MRI of broken bioabsorbable crosspin fixation in hamstring graft reconstruction of the anterior cruciate ligament

PURPOSE

To report seven cases of broken bioabsorbable femoral crosspins identified by MRI in evaluation of hamstring grafts of the anterior cruciate ligament.

METHODS

Seven cases of broken bioabsorbable crosspins utilized in femoral fixation of ACL hamstring grafts were identified prospectively and retrospectively from our PACs database during a period from 9/1/08 to 8/31/09. All imaging was performed using 1.5 or 3.0 Tesla MRI and were evaluated for T2 signal within and surrounding the crosspin, osteolysis surrounding the fragments, displacement of fragments, and graft integrity. Time from surgery was also recorded.

RESULTS

Seven cases of hamstring grafts with broken bioabsorbable crosspins were imaged 4 months to 3 years following grafting. There was osteolysis surrounding the crosspin in all but one case in which the graft was intact but a pin fragment was displaced into the joint. One graft failed due to aseptic foreign-body reaction to the fixation with aggressive osteolysis at 9 months post surgery. In the remaining five, the ACL graft was either completely torn, partially torn, lax, or degenerative and frayed. Of these, the crosspins were broken and angulated with osteolysis surrounding the apex of the angulated fragment or demonstrated lateral extrusion of the peripheral fragment.

CONCLUSIONS

Bioabsorbable crosspins utilized in femoral fixation of hamstring graft reconstruction of the ACL may become fractured. While the natural history of osteo-integration of these devices as demonstrated by MRI has not been defined, osteolysis surrounding the fragments, extrusion or displacement of the fragments, and graft laxity or failure would suggest that these are abnormal findings that should be reported.

Material properties and composition of soft-tissue fixation

Surgical interference screws and suture anchors for attaching soft tissue, such as ligaments and tendons, to bone are routinely used in arthroscopic surgery and sports medicine. Interference screw fixation provides a press fit between bone, graft/tendon, and screw and is frequently used to attach replacement ligaments in tunnels drilled for anterior and posterior cruciate ligament reconstruction. Suture anchors are used in surgical procedures wherein it is necessary for a surgeon to attach (tie) tissue to the surface of the bone, for example, during joint reconstruction and ligament repair or replacement. The composition of these implants ranges from metals to polymers and composites. Typically, because of the relatively large amount of torque that must be applied during insertion, these screws are constructed from metal. However, interference screws and suture anchors have also been constructed from bioabsorbable polymers and composites. The ideal material would (1) provide adequate mechanical fixation, (2) completely degrade once no longer needed, and (3) be completely replaced by bone. Because no material has been shown to be superior for all applications, the surgeon must weigh the advantages and disadvantages of each to evaluate the optimum material for a given application and patient. The purpose of this article is to present a comprehensive review of the commercially available interference screws and suture anchors, with an emphasis on implant composition, interaction, and design. This article provides the orthopaedic surgeon with a background on biomaterials, specifically those used in interference screws and suture anchors. Because there is no material that is perfect for all surgical situations, this review can be used to make educated decisions on a case-by-case basis.

The unpredictable material properties of bioabsorbable PLC interference screws and their adverse effects in ACL reconstruction surgery

The aim of this study was to look at the clinical outcome of polylactide carbonate (PLC) interference screws in knee ligament reconstruction surgery. We prospectively followed up 59 patients who underwent primary hamstring anterior cruciate ligament (ACL) reconstructions using PLC (Calaxo screw; Smith and Nephew, Andover, MA) screws to secure the graft in the tibial tunnel. The average age was 34 years (range 17-55 years, SD 8.93). Twenty-three (39%) patients presented with complications [synovitis in 15% (nine) patients, prominent tibial swelling in 34% (20) patients and both in seven patients]. In comparison, similar complications were not seen in two groups of 59 age and sex matched patients in whom PLLA (Bio RCI; Smith and Nephew, Andover, MA) screws or Titanium (RCI; Smith and Nephew, Andover, MA) screws were used by the same surgeon. The problems encountered in the PLC screw group did not adversely affect knee stability. Six patients underwent exploration of the tibial tunnel site. A sterile white cheesy substance was removed, leaving an empty tibial tunnel. The ACL graft was found to be well attached to tibial tunnel in all cases. The PLC screw diameter, surface area or tibial tunnel diameter did not have any correlation to the occurrence of complications. Two patients required multiple washouts, one of whom developed a deep infection. The degradation of PLC screws does not follow the gradual and controlled pattern demonstrated in the ovine model. The unpredictable screw degradation, and the reaction to it can lead to serious clinical consequences.

A clinical review of bioabsorbable interference screws and their adverse effects in anterior cruciate ligament reconstruction surgery

Bioabsorbable material screws are widely used in various surgical specialties. One popular application is their use as interference screws in anterior cruciate ligament (ACL) reconstruction surgery. Despite their routine use, a major concern with bioabsorbable materials in surgery has been the incidence of adverse events. Various case reports, series reports and studies in the past years have reported complications specific to the use of bioabsorbable interference screws intra operatively and at different time periods post operatively. The aim of this literature review is to summarize the clinical studies where bioabsorbable screws have been used in ACL reconstruction surgery and in particular to highlight any specific complications and adverse effects related to the use of these materials.

Spontaneous locking of the knee after anterior cruciate ligament reconstruction as a result of a broken tibial fixation device

The Intrafix device (DePuy Mitek, Raynham, MA) is one of a number of recently developed products whose aim is to improve fixation of quadrupled hamstring grafts when used for anterior cruciate ligament reconstruction. We present a case of failure and intra-articular migration of the sleeve of an Intrafix device causing locking of the knee 10 weeks after anterior cruciate ligament reconstruction. We were unable to identify the cause of the failure or migration of the device. Rehabilitation had been progressing normally and without incident. The broken fragments were removed arthroscopically, and the reconstruction was found to be intact and healing well. Presumably, the device retained enough mechanical function to allow healing to progress, despite failure of the sleeve. This is, to our knowledge, the first reported case of such an event occurring with the new generation of hamstring graft fixation devices.

Delayed surgical intervention for a severe fixed flexion deformity of the knee following anterior cruciate ligament reconstruction

We report a case of severe fixed flexion deformity of the knee, following anterior cruciate ligament (ACL) reconstruction, due to protrusion of the bone block and fixation screw into the knee joint above the tibial tunnel. This was treated successfully after a latent period of 6 years with surgical intervention. This case highlights the importance of critical review of radiographic imaging when faced with a fixed flexion deformity of the knee after ACL surgery and the ability to achieve a good outcome from simple surgical intervention even after a long latent period.

Recurrent locking of knee joint caused by intraarticular migration of bioabsorbable tibial interference screw after arthroscopic ACL reconstruction

Two cases are reported in which, after ACL reconstruction with autologous hamstring grafts, tibial polylactide interference screws migrated into the knee joint. Clinically, both patients presented with recurrent locking of the joint. In one case, a broken 15 mm-long tip of the screw was found intra-articularly. In the other case, the whole screw had migrated into the joint cavity. The degradation process of polylactic acid, operative technique and bone quality are discussed as possible reasons for these complications.

The migration of a BioScrew as a differential diagnosis of knee pain, locking after ACL reconstruction: a report of two cases

INTRODUCTION

Problems with the initial fixation strength and widening of the femoral and tibial canal after ACL reconstruction using a triple or quadruple semitendinosus autograft have led to the introduction of the so-called Hybrid fixation with the additional use of interference screws. Pain and intraarticular migration have been reported with metal interference screws requiring implant removal (Am J Knee Surg 11:32-34, 2000, Arthroscopy 11:289-291, 1995) but not yet with bioabsorbable screws.

MATERIALS AND METHODS

We report on two cases were the intraarticular position of a bioabsorbable interference screw possibly due to migration in the early postoperative period lead to symptoms, the need for further surgery, and implant removal.

RESULTS

A preoperative MRI revealed the diagnosis. After removal of the tibial interference screw both knees were settling down, albeit with residual instability and only a moderate clinical result.

DISCUSSION

Despite the attractiveness of bioabsorbable screws due to the very fact that they are being reabsorbed over time, there is a slight risk of migration in the first month after the operation. In any suspicious case an MRI will easily clarify the diagnosis.

Broken Delta interference screw after ACL reconstruction: a report of two cases

We report two cases of an intra-articular dislocation of the proximal part of a broken biodegradable interference screw (Delta screw) used for tibial fixation of a semitendinosis gracilis graft in an unstable knee.

Intraarticular migration of a broken biodegradable interference screw after anterior cruciate ligament reconstruction

Poly-L: -lactic acid biodegradable screws have been used effectively for graft fixation in anterior cruciate ligament (ACL) reconstruction. The overall complication rate associated with the use of this implant is low, although some authors reported complications, such as osteolysis and aseptic effusion of the knee joint. We report a case of a 29-year-old female patient with a failure of a biodegradable interference screw at 22 months after ACL reconstruction using bone-patellar tendon-bone graft. In this illustrated case, the screw broke and migrated into the knee joint. In addition, we performed a detailed review of the medical literature from 1990-2005 to identify possible causes of biodegradable screw failures. We identified six published cases of bioabsorbable interference screw failure with migration into the knee joint. Several authors have reported small diameter of the screw, poor bone quality, bone resorption, and screw divergence as potential causes for intraarticular migration of metallic interference screws. With regard to bioscrews, no specific risk factors for screw breakage and intraarticular migration have been reported. ACL reconstruction with the use of bioabsorbable interference screws for fixation is considered to be reliable. However, we need to be aware of potential problems associated with the use of this implant. Early recognition of bioscrew failure may prevent associated morbidities, such as subsequent cartilage damage.

Prospective evaluation of patellar tendon graft fixation in anterior cruciate ligament reconstruction comparing composite bioabsorbable and allograft interference screws

PURPOSE

Bioabsorbable interference screws have proved to be biologically safe and to provide adequate graft fixation. Metallic interference screws have therefore been continuously replaced over the years. However, degradation times are highly variable, and bony replacement of the screw does not always occur in human beings. Composite interference screws have recently been introduced to enhance bony integration. We evaluated 2 different composite interference screws and compared them with an allograft interference screw over a 2-year period after anterior cruciate ligament (ACL) reconstruction with an autologous bone-patellar tendon-bone graft.

METHODS

Three groups of patients were prospectively evaluated. Poly-L-lactid acid/hydroxyapatite composite screws (BioRCI-HA; Smith & Nephew, Andover, MA) (group A), poly-L-lactid acid/beta-tricalcium phosphate composite screws (Bilok; Atlantech, Radevormwald, Germany) (group B), or allograft interference screws (CorlS; Regeneration Technologies, Alachua, FL) (group C) were used for tibial fixation of a patellar tendon autograft in ACL reconstruction. Each group consisted of 20 patients (mean age, 32.2 +/- 10.9 years in group A, 32.3 +/- 10.6 years in group B, and 31.1 +/- 6.6 years in group C) with no significant (P < .05) differences in age, sex, and time of follow-up. Subjective and clinical International Knee Documentation Committee parameters were evaluated preoperatively and at 3, 12, and 24 months postoperatively; computed tomography scans were obtained postoperatively and at 3, 12, and 24 months; and magnetic resonance imaging (MRI) scans were obtained at 3 and 24 months postoperatively.

RESULTS

Screw breakage during insertion occurred in 2 cases (1 in group A and 1 in group B). There was no significant (P < .05) difference in subjective and clinical results at any time of follow-up. No inflammatory response could be detected on MRI in any of the patients in all groups. Computed tomography scans documented complete bone block incorporation at 3 months in all groups. Both composite interference screws showed signs of degradation but were still clearly visible 24 months after ACL reconstruction. At 12 months, a sclerotic rim around the screw cavity could be outlined in group B only. No bony replacement had taken place up to 24 months postoperatively in group A or B. In group C the allograft bone screw was completely integrated and barely visible after 24 months.

CONCLUSIONS

All 3 screw types provided adequate graft fixation and were associated with excellent clinical results and no inflammatory response on MRI. Ultimately, a resorbable screw has to be replaced by bone to facilitate revision surgery. Formation of a sclerotic rim around the outline of the screw makes later bony replacement (group B) unlikely. After 24 months, complete bony integration had only taken place when allograft screws were used.

CLINICAL RELEVANCE

At 24 months, no advantage of composite screw materials over conventional bioabsorbable screws could be detected. If composite materials will be of any advantage with respect to bony replacement has to be observed with longer-term follow-up. The allograft bone screw was completely incorporated and replaced by cancellous bone after 24 months. Unfortunately, the screw's more complicated handling, higher cost, and limited availability impair the possibilities for its standard clinical use.

Severe cartilage damage by broken poly-L-lactic acid (PLLA) interference screw after ACL reconstruction

Poly-L-lactic acid (PLLA) bioabsorbable interference screws are widely used for fixation of tendon to bone and bone to bone in anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstructions. Complications are rare. To our knowledge this is the first report of severe chondral damage caused by late breakage of the screw. Breakage of bioscrews has only been published in cases with tendon to bone fixation.

Loose intra-articular body following anterior cruciate ligament reconstruction

We report a case of intra-articular fracture of a bioabsorbable fixation device from the femoral tunnel in an anterior cruciate ligament reconstruction using a bone-tendon-bone graft. Thirteen months after successful reconstruction surgery, the patient experienced episodes of locking and medial joint pain. There was no history of trauma and no symptoms of instability or swelling. On revision arthroscopy, a fractured tip of a bioabsorbable RIGIDfix cross pin (Mitek, Westwood, MA) was identified in the medial compartment of the knee. There was a broad area of chondral erosion affecting the medial femoral condyle and a small defect to the medial tibial plateau where the loose body had been lodged. The bone-tendon-bone graft was intact without disruption. After arthroscopy, the patient was symptom free for 3 weeks but then developed further symptoms of locking. Magnetic resonance imaging showed another loose body within the knee. A repeat arthroscopy was performed 6 weeks after the earlier procedure and another piece of the polylactic acid RIGIDfix cross pin was removed, this time from the lateral gutter. This case raises concern about the potential for breakage and resultant loose body formation that may occur after bioabsorbable cross-pin fixation and, particularly, the associated chondral damage that can occur if early intervention is not conducted.

Biodegradable screw presents as a loose intra-articular body after anterior cruciate ligament reconstruction

We report a case of intra-articular movement of a broken piece of a poly-L-lactide (PLLA) bioabsorbable interference screw from the femoral tunnel in anterior cruciate ligament (ACL) reconstruction with quadrupled semi-tendinosus and gracilis tendon grafts. Eleven months after initially successful ACL surgery, the patient felt a sudden locking of the knee without associated trauma or injury. The patient experienced pain and swelling episodes after heavy lifting with knee flexion at work, but without symptoms of giving way or locking. On revision arthroscopy, a broken part of a bioabsorbable interference screw was seen in the lateral compartment, which was subsequently removed without incident. The semitendinosus-gracilis graft appeared intact without disruption. After revision surgery, the patient's recovery was uneventful, with return to activity within a few months. This case further shows the problem of biointerference screw breakage in ACL reconstructive surgery and the need to bury the femoral bioabsorbable interference screw on graft fixation.