Bioabsorbable PLLA/PLGA Interference Screws: What Patients Should Know About Complication and Failure Risks

Published by Justpoint Inc.

If you had anterior cruciate ligament (ACL) reconstruction, syndesmotic ankle repair, or another ligament or tendon procedure in which a bioabsorbable screw was used to anchor the graft, the published medical evidence points to two specific concerns. Bioabsorbable interference screws made of poly-L-lactic acid (PLLA) or poly-lactide-co-glycolide (PLGA) carry roughly a 73% higher risk of overall treatment failure than metallic screws (relative risk 1.73), and a more-than-threefold higher overall complication rate in syndesmotic fixation (relative risk 3.35; 95% confidence interval 1.75 to 6.42) (Cureus systematic review, 2026). For people who already had surgery with these screws, that translates into an elevated chance of needing a second operation.

This article explains what these screws are, what can go wrong as the material degrades, how to verify whether your specific implant was bioabsorbable, what symptoms to watch for, and what concrete steps to take if you are concerned.

What bioabsorbable interference screws are

An interference screw is a threaded fixation device that sits in a bone tunnel alongside a tendon or ligament graft. The screw wedges the graft against the tunnel wall, allowing it to heal in place. Interference screws are most commonly used in:

• Anterior cruciate ligament (ACL) reconstruction of the knee — anchoring a hamstring, patellar-tendon, or quadriceps-tendon graft inside drilled tunnels in the femur and tibia
• Syndesmotic (ankle) repair — fixing the tibia and fibula together after a high-ankle-sprain disruption of the distal tibiofibular syndesmosis
• Other ligament and tendon fixation at the shoulder, elbow, ankle, foot, hand, and wrist

Traditional interference screws are made of titanium or stainless steel and remain in the body permanently. Bioabsorbable screws were introduced as an alternative designed to dissolve gradually in the body over months to years, theoretically eliminating the need for a second surgery to remove hardware and reducing imaging artifacts. The polymers most commonly used are:

• Poly-L-lactic acid (PLLA) — slow-degrading, often taking five years or more for full absorption
• Poly-lactide-co-glycolide (PLGA) — faster-degrading than pure PLLA
• Composite formulations that blend PLLA, PLGA, or related polylactide stereoisomers with biphasic calcium phosphate or beta-tricalcium phosphate to improve mechanical strength and promote bone ingrowth

The U.S. Food and Drug Administration classifies bioabsorbable interference screws as Class II medical devices under product code MAI (“Fastener, Fixation, Biodegradable, Soft Tissue”), regulation 21 CFR 888.3030. Class II is a moderate-risk classification: the manufacturer must demonstrate “substantial equivalence” to a previously cleared device through the 510(k) premarket-notification pathway rather than running a full premarket-approval clinical trial.

The two manufacturers most commonly identified in the regulatory record are Arthrex, Inc. (Naples, Florida — maker of the BioComposite Interference Screw line, a 70% PLDLA / 30% biphasic-calcium-phosphate blend) and Inion Oy (Tampere, Finland — maker of the Hexalon and FreedomScrew bioabsorbable screws). Other companies, including ConMed Linvatec and DePuy Mitek, have also marketed bioabsorbable interference screws under product code MAI.

What goes wrong with bioabsorbable interference screws

The clinical experience accumulated since these screws entered widespread use has identified a recurring set of complications. These are not rare manufacturing defects — they have been described as failure modes associated with how the polymer behaves once implanted in living tissue.

Cyst formation. As PLLA or PLGA breaks down, the surrounding tissue can react to polymer fragments and degradation byproducts. A possible result is a fluid-filled cavity at or around the screw site. Published case series have shown that cyst formation can appear years after the original surgery — including new cysts arising five to ten years post-operation (Sprowson et al., 2012) — and is frequently associated with a foreign-body inflammatory response. Cysts are sometimes visible on MRI before they cause symptoms.

Screw breakage. Bioabsorbable screws are mechanically weaker than metal and can be brittle. Breakage has been reported both during insertion (when the surgeon is driving the screw down the tunnel) and before complete graft healing has occurred (Watson et al., 2015). A broken screw may leave fragments inside the joint or tunnel.

Tunnel widening. As the polymer degrades, the bone tunnel that originally held the screw can enlarge. Wider tunnels can compromise graft fixation, increase the technical difficulty of any revision surgery, and have been linked to clinical instability.

Foreign-body inflammatory reaction. Histologic studies of explanted screws and biopsied cysts have shown polymer fragments surrounded by foamy histiocytes and other inflammatory cells — a classic foreign-body reaction (Gonzalez-Lomas et al., 2011). This reaction has been associated with pain, swelling, warmth, and chronic discomfort in the area of the implant.

Pretibial swelling and pain. In ACL reconstructions where a tibial screw is used, swelling and tenderness over the front of the shin (the pretibial area) is a documented complication. It typically reflects an underlying cyst or inflammatory reaction at the tibial tunnel.

Graft loosening and treatment failure. The combined effect of weakened fixation, tunnel widening, and inflammation may compromise the graft and may be associated with treatment failure. The 2026 systematic review and meta-analysis that anchors this article found a relative risk of 1.73 for overall treatment failure with bioabsorbable screws compared with metallic screws — meaning bioabsorbable-screw patients were roughly 73% more likely to experience a failure outcome (Cureus systematic review, 2026).

Damage to joint structures. Loose polymer fragments, broken screw pieces, or screw migration into the joint space have been reported as causes of intra-articular damage requiring debridement or revision.

The published evidence

The current best evidence on this safety question comes from a systematic review and meta-analysis published in February 2026:

Stability at a Cost: Evaluating Postoperative Complications in Bioabsorbable vs. Metallic Syndesmotic Fixation: A Systematic Review — published in Cureus on February 5, 2026. The authors searched PubMed and Google Scholar, screened 332 studies, and included four randomized controlled trials encompassing 257 patients who underwent ankle syndesmotic fixation with either a bioabsorbable or a metallic screw. The pooled results showed that bioabsorbable screws were associated with:

• A higher overall complication rate, relative risk 3.35 (95% CI 1.75 to 6.42) compared with metallic syndesmotic screws
• A higher overall treatment-failure rate across orthopedic interference-screw applications, relative risk 1.73 versus metallic screws

Even pooled RCT data with heterogeneous endpoints and limited samples can be subject to between-study heterogeneity and selection bias; the figures describe associations under the studies’ conditions rather than population-wide causation.

These pooled estimates are consistent with the broader, longer-running clinical literature on bioabsorbable interference screws in ACL reconstruction and ankle fixation, in which earlier meta-analyses (Xu et al., 2021; others) identified higher complication rates — including knee effusion, foreign-body reaction, and reoperation — even when functional outcome scores were similar to those for metallic screws. The 2026 Cureus review is the most recent synthesis and uses the tightest inclusion criteria (randomized controlled trials only) for the syndesmotic-fixation comparison.

Who might be affected

Bioabsorbable interference screws were adopted widely in sports-medicine and orthopedic practice from roughly 2005 onward, with peak use through approximately 2020. The patient groups most likely to carry one of these implants are:

• People with ACL reconstructions — particularly those operated on between 2005 and 2020, when bioabsorbable fixation was a popular alternative to metal
• People with syndesmotic (ankle) repair for a high-ankle sprain or complex ankle fracture
• People with shoulder, elbow, foot, hand, or wrist ligament and tendon fixation procedures where a bioabsorbable interference screw was selected

Because the polymer degrades slowly, complications can emerge months to years after the original surgery. Cyst formation in particular has been documented as late as ten years post-operation. If you have a bioabsorbable screw and are currently symptom-free, that does not rule out the possibility of a future complication — the timeline of polymer degradation runs over years.

How to confirm you have a bioabsorbable interference screw

If you are not sure what kind of screw was used in your surgery, three pathways can confirm it:

1. Your operative report. The hospital or surgical center is required to keep the operative report from your procedure. The report will identify the device manufacturer (for example, Arthrex, Inc.; Inion Oy; ConMed Linvatec; DePuy Mitek), the model name (BioComposite Interference Screw, Hexalon, BioScrew, Milagro, and so on), and the lot or catalog number. Request a copy through the hospital’s medical-records department. There is no charge in most jurisdictions for a copy of your own surgical record.
2. Your implant card or patient booklet. Many orthopedic surgeons issue patients a wallet-sized implant card or an information booklet at discharge identifying the device. Check any paperwork you received after surgery.
3. Your surgeon’s office. Your orthopedic surgeon’s office maintains records of devices used in each procedure. A phone call or patient-portal message asking specifically — “What screw was used in my [date] ACL reconstruction (or syndesmotic repair) — manufacturer, model name, and catalog number?” — is usually answered within a few business days.

Once you have the device information, look for the words “bioabsorbable,” “biodegradable,” “absorbable,” “PLLA,” “PLDLA,” “PLGA,” “poly-L-lactic acid,” “poly-lactide-co-glycolide,” or any specific bioabsorbable product name (BioComposite, BioScrew, Hexalon, Milagro, RCI-Bio) in the documentation.

What to do if you are concerned

If you are experiencing symptoms or have concerns about a bioabsorbable interference screw, the following information may help guide conversations with your healthcare provider.

1. Consider discussing your symptoms or concerns with an orthopedic surgeon or sports-medicine specialist. Bring (or send ahead) any operative reports, implant cards, and a written symptom timeline.
2. Ask about imaging. Magnetic resonance imaging (MRI) and computed tomography (CT) can show cyst formation, tunnel widening, and screw fragmentation. Bioabsorbable screws produce far less imaging artifact than metal, so MRI evaluation is usually informative.
3. If a healthcare provider determines that treatment is necessary, management approaches may vary depending on the findings. In some cases, this can include continued monitoring, imaging follow-up, or additional procedures. Treatment decisions are individualized and depend on the patient’s symptoms, imaging findings, and overall clinical picture.
4. Report any device-related adverse event to the FDA. Patient and caregiver reports help the FDA identify safety patterns across thousands of similar devices.

Reporting a problem to the FDA

You can report adverse events from a medical device directly to the FDA’s MedWatch program:

• Online: www.fda.gov/medwatch
• Phone: 1-800-FDA-1088 (1-800-332-1088)

A MedWatch report does not initiate a legal claim and is not a substitute for medical care. It does, however, contribute to the FDA’s Manufacturer and User Facility Device Experience (MAUDE) database, which is one of the FDA’s main tools for monitoring post-market device safety. MAUDE adverse-event reports are voluntary, subject to reporting and selection bias, and reflect associations rather than established device causation. Your treating clinician can also file a report on your behalf.

Regulatory and legal context

As of this writing, the FDA has not issued a class-wide recall of bioabsorbable interference screws. Individual manufacturers have issued limited Class 2 recalls of specific lot numbers over the years, but the published evidence on complication and failure rates reflects a recognized material limitation of the polymer technology rather than a single manufacturing defect.

Bioabsorbable interference screws continue to be sold and used in U.S. orthopedic practice. Whether — and how aggressively — patients with bioabsorbable implants from earlier eras should be monitored is an active question among orthopedic surgeons, and recommendations vary among practitioners.

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Sources and how to verify

• Cureus systematic review (2026): “Stability at a Cost: Evaluating Postoperative Complications in Bioabsorbable vs. Metallic Syndesmotic Fixation: A Systematic Review.” Published February 5, 2026. Four randomized controlled trials, 257 patients. Reports relative risk 3.35 (95% CI 1.75–6.42) for overall syndesmotic complications and relative risk 1.73 for overall treatment failure with bioabsorbable interference screws compared to metallic screws.
• FDA Product Classification — code MAI: “Fastener, Fixation, Biodegradable, Soft Tissue,” Class II, regulation 21 CFR 888.3030. Searchable in the FDA Product Classification Database at accessdata.fda.gov/scripts/cdrh/cfdocs/cfpcd/classification.cfm.
• FDA 510(k) Premarket Notification Database: Search at accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm by manufacturer name (Arthrex; Inion; ConMed Linvatec; DePuy Mitek) or product code (MAI) to identify the specific device cleared for your surgery.
• FDA MAUDE (adverse-event database): Search at accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/search.cfm to review reported adverse events for bioabsorbable interference screws by manufacturer or device name.
• FDA Medical Device Recalls database: Search at fda.gov/medical-devices/medical-device-safety/medical-device-recalls-and-early-alerts for any recall actions concerning the specific manufacturer or product line.
• Earlier supporting literature on cyst formation, foreign-body reaction, and tunnel widening: published case series in Knee, Knee Surgery, Sports Traumatology, Arthroscopy, and American Journal of Sports Medicine, searchable on PubMed at pubmed.ncbi.nlm.nih.gov using terms such as “bioabsorbable interference screw cyst,” “pretibial cyst ACL,” and “PLLA screw foreign-body reaction.”
• Manufacturer information:
  • Arthrex, Inc. — 1370 Creekside Boulevard, Naples, FL 34108-1945. Customer service: (800) 933-7001.
  • Inion Oy — Tampere, Finland. www.inion.com.
• FDA MedWatch (adverse-event reporting): www.fda.gov/medwatch or 1-800-FDA-1088.

This article was published by Justpoint Inc. The information provided is for educational purposes, does not constitute medical or legal advice and is based on publicly available research and regulatory communications. Findings may vary depending on individual circumstances, device type, and clinical context. If you have a medical device that may be affected, please consult your physician. If you believe you may have a legal claim, please consult a qualified attorney.

Justpoint Inc. supports Justpoint Law (Justpoint PLLC) by providing operational and administrative services. All legal services are provided by Justpoint Law, and any client-related communications are made on its behalf.