Utility of Bioabsorbable Fixation of Osteochondral Lesions in the Adolescent Knee: Outcomes Analysis With Minimum 2-Year Follow-up

Background: Osteochondral lesions (OCLs) of the knee, whether occurring secondary to osteochondritis dissecans or a traumatic osteochondral fracture, are commonly encountered in the pediatric and adolescent population. Given the potential for healing in this population, coupled with adequate surgical reduction and stability of OCL fixation, an opportunity exists to avoid a major restorative procedure and the associated substantial costs and potential morbidity. Purpose: To analyze the outcomes of bioabsorbable fixation of OCLs in the adolescent knee at a minimum of 2 years. Study Design: Case series; Level of evidence, 4. Methods: An institutional review board–approved retrospective review was performed of patients younger than 18 years who underwent bioabsorbable fixation of an OCL of the knee with a minimum 2-year follow-up. Patient demographics, operative details, and postoperative clinical findings were detailed and recorded. All cases were performed by a single surgeon. Results: There were 38 patients treated surgically for an OCL between 2009 and 2016. Of these, 38 patients (mean age, 14.7 years) were evaluated at a mean of 59 months. OCL fixation consisted of a mean of 1.4 bioabsorbable screws and 1.5 darts. At final follow-up, mean pre- and postoperative Tegner scores were 6.6 and 6.4, respectively, while Lysholm and Pediatric International Knee Documentation Committee scores were 89.8 and 88.1, respectively. A total of 6 patients underwent secondary procedures postoperatively. One patient required a secondary procedure related to OCL fixation, which was secondary to a proud implant. The other secondary procedures included second-look arthroscopic surgery for pain after an injury postoperatively, planned anterior cruciate ligament reconstruction, staged medial patellofemoral ligament reconstruction, and manipulation under anesthesia for arthrofibrosis (n = 2). None of the 32 patients required a revision cartilage procedure at the time of final follow-up. Conclusion: The use of bioabsorbable implants in the adolescent knee appears to be a safe and efficacious treatment with good functional outcomes at long-term follow-up and a low revision rate. Additional long-term multisurgeon and multicenter trials with a larger cohort are needed to further elucidate the role of bioabsorbable fixation of an OCL in the adolescent knee.

Biomechanical Properties of Bioabsorbable Fixation for Osteochondral Shell Allografts

This study compares bioabsorbable nail to metal screw fixation of shell osteochondral allograft (OCAs) for compression and shear strength. Cadaveric distal femurs (n = 5) yielding six 1.5 cm shell grafts (n = 30) were used. Three different fixation methods (2.0 and 2.4 mm headed screws, and copolymer absorbable nail) were compared for statistically significant differences (p < 0.05) in contact area, contact pressure, and shear load-to-failure. No significant differences in contact areas existed among groups (224 ± 33.5 mm2; 233.9 ± 20.8 mm2, 220.6 ± 22.7 mm2; p = 0.509 for 2.4, 2.0 mm screw, and nail, respectively). No significant differences in contact pressures existed (1.7 ± 0.6 MPa/mm2, 1.5 ± 0.8 MPa/mm2, 1.4 ± 0.9 MPa/mm2; p = 0.73 for 2.4, 2.0 mm screw, and nail, respectively). Load-to-failure for each was: 280.7 ± 48.4 N for 2.4 mm screws, 245.1 ± 70.6 N for 2.0 mm screws, and 215.2 ± 39.4 N for nails. There were no statistically significant differences in load-to-failure between 2.4 and 2.0 mm screws (p = 0.29) or between 2.0 mm screws and nails (p = 0.23); however, load-to-failure in shear was significantly higher for 2.4 mm screws compared with nails (p = 0.036). Fixation of shell OCAs using a copolymer headed nail provides initial graft-recipient compression similar to fixation using 2.0 and 2.4 mm headed screws. Nails failed in shear at significantly lower load than 2.4 mm screws but not 2.0 mm screws which have proven adequate for clinical healing. This study has clinical relevance, as a copolymer bioabsorbable headed nail (SmartNail) has graft-recipient compression and shear load-to-failure properties that suggest it is viable for shell OCA fixation.

Bioabsorbable Anchors for Medial Patellofemoral Ligament Reconstruction

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

Bioabsorbable Fixation Screw for Proximal Interphalangeal Arthrodesis of Lesser Toe Deformities

Background: Although standard fixation of proximal interphalangeal (PIP) arthrodesis by K-wire is relatively inexpensive and well established, it does have some drawbacks, making newer fixation devices interesting. The aim of this study was to clinically and radiologically assess the operative correction of the lesser toe deformation in the form of a PIP arthrodesis using a bioabsorbable 2.7-mm fixation screw. Methods: From January 2011 until October 2013, 34 patients underwent a PIP arthrodesis using the TRIM-IT (Arthrex) 2.7-mm fixation screw and were contacted for this retrospective cohort study. At an average of 3.3 years after the operation, 24 patients and 26 toes were evaluated clinically, radiologically, through pedobarography, and a patient-satisfaction survey. Results: Using the PLLA screw for fixation, 84.6% showed bony union of the arthrodesis, and 84.6% were satisfied. Mean AOFAS score was 82.7 points and thus regarded as good. The mean VAS score was 1.3/10. Overall, 73.1% of the toes showed good alignment, and 7.7% had a painless recurrence of deformity and were still satisfied with the intervention. In addition, 34.6% had floating toes, but only 4.2% without Weil osteotomy or encroachment. Further, 3.8% were advised to undergo a revision because of severe misalignment. Conclusion: The 2.7-mm bioabsorbable fixation screw yielded results that were comparable to other fixation devices for PIP fusion fixation regarding success rate, revisions, and patient acceptance. Level of Evidence: Level IV, retrospective case series.

BIOABSORBABLE FIXATION OF SCAPHOID FRACTURES AND NON-UNIONS; ANALYSIS OF EARLY CLINICAL OUTCOMES

The vast majority of devices used for internal fixation of the scaphoid are metallic. This two-center study aimed to report the results of scaphoid fixation using a cannulated, bioabsorbable device made from a hydroxyapatite and poly-L-lactide composite in 29 consecutive patients. Fixation was performed for seven acute fractures and twenty-two established non-unions. Union was achieved in 72.4% of patients. Six of the acute fractures and fifteen of the non-unions united successfully. Modified Mayo Wrist Score ranged between good to excellent in all patients who successfully united, whereas patients who failed to unite ranged between poor to excellent, with one poor and two moderate scores. No adverse biocompatibility reactions were seen. Two failures with broken screws were re-explored and one of these was thought to be due to screw mal-placement. The device used is an alternative to conventional metal implants and produces comparable union rates to metallic devices in the short term.