Extra-articular migration of PEEK interference screw after anterior cruciate ligament reconstruction: a report of two cases

Application-driven validation of posteriors in inverse problems

Current deep learning-based solutions for image analysis tasks are commonly incapable of handling problems to which multiple different plausible solutions exist. In response, posterior-based methods such as conditional Diffusion Models and Invertible Neural Networks have emerged; however, their translation is hampered by a lack of research on adequate validation. In other words, the way progress is measured often does not reflect the needs of the driving practical application. Closing this gap in the literature, we present the first systematic framework for the application-driven validation of posterior-based methods in inverse problems. As a methodological novelty, it adopts key principles from the field of object detection validation, which has a long history of addressing the question of how to locate and match multiple object instances in an image. Treating modes as instances enables us to perform mode-centric validation, using well-interpretable metrics from the application perspective. We demonstrate the value of our framework through instantiations for a synthetic toy example and two medical vision use cases: pose estimation in surgery and imaging-based quantification of functional tissue parameters for diagnostics. Our framework offers key advantages over common approaches to posterior validation in all three examples and could thus revolutionize performance assessment in inverse problems.

Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients Using an All-Epiphyseal Technique: A Prospective Cohort Study

Background

Transphyseal techniques are the most commonly used for anterior cruciate ligament (ACL) reconstruction in children. To mitigate the risk of growth disturbance, the tunnels should be positioned as vertically and centrally as possible in relation to the physis, potentially compromising the anatomic orientation of the graft and, therefore, its isometry. A graft rupture is frequent in this age group. Even though all-epiphyseal techniques have not clearly demonstrated better isometry, the authors propose an epiphyseal technique that aims for favorable anatomy, and therefore isometry, while avoiding physeal damage in young children with ACL ruptures.

Purpose

To present the results of a modified all-epiphyseal technique in prepubertal patients, evaluating knee function, graft survival, and joint and growth protection.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 74 skeletally immature patients with a traumatic ACL rupture underwent a physeal preserving technique using a semitendinosus-gracilis tendon graft fixed with intra-epiphyseal resorbable interference screws in the femur and tibia, along with associated minimal notchplasty. Preoperative, intraoperative, and postoperative assessments included clinical knee stability and meniscal status, magnetic resonance imaging, isometry measurements, comparative laximetry measurements with stress radiography using the Lerat method, full-length standing radiography, measurements of the axes of the lower limbs, Tegner and Lysholm scores, and patient satisfaction.

Results

From 2004 to 2014, a total of 74 patients met our inclusion criteria and were followed up for a mean of 4.1 years (range, 2-7 years). Of these patients, 91.9% had an excellent/good postoperative Lysholm score, with similar preoperative and postoperative Tegner activity scores. Intraoperative isometry showed an intratunnel graft excursion <3 mm during extension in 95.9% of cases. Abnormal clinical laxity was observed in 4.1% at final follow-up, with an improvement in side-to-side laxity of 4.8 mm. There were 3 patients who experienced graft failure, with the salvage procedure employing a transphyseal technique in 1 patient. Meniscal tears occurred in 27.0%, with concomitant repair yielding a healing rate of 87.5%. No physeal alterations were observed, except for a tendency toward subtle overgrowth in the affected limb. Also, 90.5% of patients were satisfied or very satisfied with the outcome.

Conclusion

The proposed all-epiphyseal technique in skeletally immature patients demonstrated excellent overall results with a low incidence of reruptures and meniscal degeneration, without relevant alterations related to growth.

Retrospective cohort study comparing postoperative joint stability between all-inside PCL reconstruction technique and conventional PCL reconstruction technique in patients with multiligament knee injury

Objectives

The purpose of our study was to compare (1) posterior cruciate ligament (PCL) laxity, (2) patient-reported outcome, and (3) complications after the all-inside PCL reconstruction (Al-PCLR) technique and conventional PCLR (CON-PCLR) technique at minimum 2-year follow-up. We hypothesized that AI-PCLR and CONV-PCLR would yield similar results in PCL laxity, patient-reported outcomes, and complications.

Method

A retrospective cohort study was conducted on patients who underwent PCLR with the Al-PCLR technique and CON-PCLR technique from 2012 to 2023 in a single hospital. Medical records were reviewed for patients' demographic data, the technique of PCL reconstruction and complications. Patient-reported outcome scores, including International Knee Documentation Committee (IKDC), Tegner activity scale, and Lysholm score, as well as bilateral kneeling radiographs and physical examinations, were collected at least 2 years postoperatively.

Results

Included in the study were 24 patients: 11 who underwent the CON-PCLR technique (mean age 40.7 +years) and 13 who underwent Al-PCLR (mean age 34.3 + 12.9 years). Three patients in AI-PCLR group were lost to follow-up and one patient is the CON-PCLR group, a revision case, was excluded from the study.Bilateral stress kneeling radiographs showed a similar side-to-side difference between two groups (CON-PCLR vs AL-PCLR: mean 7.5 ± 5.2 vs 5.8 ± 4.8 mm; P = 0.38) There were no statically significant differences between the two groups in postoperative IKDC (CON-PCLR vs AL-PCLR: 68.9 vs 73.9; P = 0.37), Lysholm (89.1 vs 94.1; P = 0.42), or Tegner activity (6 vs 6.4; P = 0.68) scores.

Conclusion

All-inside PCLR demonstrates comparable stability to Conventional PCLR, with satisfactory patient-report outcome at minimum 2 years follow up and low rate of complications in patients with multiligament knee injury.Level of evidence: III Retrospective comparative study.

Clinical Outcomes of Modified Suture Buttons for Tibial Side Fixation in Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Study

Introduction Restoring knee joint stability and resuming sports activities are important objectives of anterior cruciate ligament (ACL) reconstruction. The maintenance of anterior knee stability after ACL reconstruction is contingent on graft tension. Various devices and techniques have been used to achieve robust tibial graft tendon fixation, and their advantages and disadvantages are established. However, a gold standard has not been established. Therefore, we aimed to determine whether anterior knee joint stability and clinical outcomes of graft tendon fixation could be improved using a recently modified suture button (MSB) compared with using an adjustable suspensory fixator (ASF) at 1 year after double-bundle ACL reconstruction. Methods This study retrospectively analyzed postoperative data derived from 79 patients at a single center between January 2016 and December 2021. The patients were assigned to groups that underwent double-bundle ACL reconstruction with tibial fixation using an MSB (n = 30) that maintains tension while tying sutures, or an ASF (n = 49). We then compared complications, clinical outcomes and knee joint stability at 1 year postoperatively. Rates of postoperative infection, graft rupture, implant removal and residual anterior knee laxity (AKL) were compared between the groups using chi-square tests. Patient-reported outcome measures (PROM) based on Forgot Joint Score-12, Knee Injury and Osteoarthritis Outcome, and Lysholm Knee scores were compared using Mann-Whitney U tests. Results One patient in the MSB group developed postoperative infection. Rates of graft rupture and implant removal in the MSB and ASF groups were 3.3% and 4.1%, and 3.6% and 10.2%, respectively. None of the PROMs differed between the groups. The proportions of postoperative AKL were 3.6% and 14.9% in the MSB and ASF groups, respectively. A trend towards lower postoperative AKL in the MSB group did not reach statistical significance (p = 0.25). Conclusions The incidence of AKL at a year after ACL reconstruction using the MSB was 3%. Postoperative AKL and clinical outcomes were comparable between the MSB and ASF groups. A low AKL rate and positive postoperative outcomes indicated that MSB could be an option for tibial-side fixation in ACL reconstruction.

Biomechanical and histological comparison of two suture configurations for soft tissue grafts: speedtrap™ versus krackow stitch

To compare 2 different graft preparation techniques to determine biomechanical strength and resultant tissue trauma evaluated by histology. Twelve common flexors of the finger's tendons were prepared with either tubulization (SpeedTrap™) or transtendon stiches (Orthocord™). The stiffness, resistance and energy at maximum load were tested for biomechanical assessment in both groups. After load testing, Samples were stained with hematoxylin and eosin (HE) to evaluate histological damage. We observe that the time to prepare tendons with SpeedTrap™ was 8.3 times faster (1:25 min) than traditional ones (15:02 min). In all cases, the mean values for SpeedTrap™ were higher in terms of strength, stiffness and energy at maximum load than for traditional suture but without significant difference (p > 0.05). The Krackow stitch produces greater structural damage to the collagen fibers while SpeedTrap™ maintains better organized arrangement of the fibers after tubulization preparation. With the results obtained, we can conclude that the tubulization technique allows faster graft preparation with less structural damage to the manipulated tissue without altering the biomechanical resistance provided by the transtendon suture technique.

Talar and fibular histiocytic-driven massive expansile osteolysis following polyetheretherketone interference screw implantation: a case report

Numerous interference screws of different compositions exist including titanium screws, bioabsorbable screws, and polyetheretherketone (PEEK) screws. PEEK-based implants are frequently used in orthopaedic surgery due to their biocompatibility, similar elastic modulus to cortical bone, and purported negligible risk of osteolysis compared with bioabsorbable screws. In this case report, we present the case of a 48-year-old healthy female who experienced a massive osteolytic reaction in the talus and fibula after 11 weeks following implantation of PEEK-based interference screws during lateral ankle ligament reconstruction. The patient subsequently underwent removal of the PEEK screws and specimens were sent for microbiological and histopathological analysis. The specimens report demonstrated fibrotic tenosynovial soft tissue with patchy chronic inflammation, oedematous reactive changes, and histiocytic reaction, with no evidence of any significant acute inflammation. The patient recovered well and was asymptomatic at 6 months postoperatively. To our knowledge, this is the first case report of a massive osteolytic reaction to PEEK-based interference screws.

Comparison of Graft Type and Fixation Method in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis Based on Randomized Control Studies

BACKGROUND

The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee. ACL reconstruction (ACLR) proves the standard for treating this injury. However, graft choice and method of fixation remain a heavily debated topic. This study investigates the following: bone-patellar tendon-bone (BPTB) vs. hamstring tendon (HT) autograft, single-bundle vs. double-bundle hamstring graft, and metal vs. bioabsorbable screws in ACLR.

METHODS

A systematic review was performed on PubMed and Google Scholar according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were collected on patient demographics, complications, and functionality scores including International Knee Documentation Committee (IKDC) and Lysholm scores. A systematic review and meta-analysis were conducted with Review Manager. Outcome measurements were determined using forest plots with significant differences considered p < 0.05.

RESULTS

Twenty-five studies were included, accounting for 2,170 patients. No statistically significant difference was appreciated when comparing BPTB to hamstring autografts. Patients who received a double bundle HT autograft exhibited significantly superior outcomes in terms of revision (p = 0.05), failure (p = 0.002), normal pivot shift tests (p = 0.04), and normal IKDC (p = 0.008). When comparing screw types, bioabsorbable screws had a greater Lysholm score (p = 0.01) and lower failure rates for copolymer screws (p = 0.03).

CONCLUSION

Overall, the data collected suggested that BPTB and HT autografts display similar postoperative results. However, if an HT autograft is used, the data suggest a double-bundle graft improves both functionality and decreases the possible complications. Finally, bioabsorbable screws prove superior to metal screws when looking at both functionality and failure rates. Further research into the superior graft type is still needed.

LEVEL OF EVIDENCE

Level II. See Instructions for Authors for a complete description of levels of evidence.

Ion Bombardment-Induced Nanoarchitectonics on Polyetheretherketone Surfaces for Enhanced Nanoporous Bioactive Implants

In spite of the biocompatible, nontoxic, and radiolucent properties of polyetheretherketone (PEEK), its biologically inert surface compromises its use in dental, orthopedic, and spine fusion industries. Many efforts have been made to improve the biological performance of PEEK implants, from bioactive coatings to composites using titanium alloys or hydroxyapatite and changing the surface properties by chemical and physical methods. Directed plasma nanosynthesis (DPNS) is an atomic-scale nanomanufacturing technique that changes the surface topography and chemistry of solids via low-energy ion bombardment. In this study, PEEK samples were nanopatterned by using argon ion irradiation by DPNS to yield active nanoporous biomaterial surface. PEEK surfaces modified with two doses of low and high fluence, corresponding to 1.0 × 1017 and 1.0 × 1018 ions/cm2, presented pore sizes of 15-25 and 60-90 nm, respectively, leaving exposed PEEK fibers and an increment of roughness of nearly 8 nm. The pores per unit area were closely related for high fluence PEEK and low fluence PEEK surfaces, with 129.11 and 151.72 pore/μm2, respectively. The contact angle significantly decreases in hydrophobicity-hydrophilicity tests for the irradiated PEEK surface to ∼46° from a control PEEK value of ∼74°. These super hydrophilic substrates had 1.6 times lower contact angle compared to the control sample revealing a rough surface of 20.5 nm only at higher fluences when compared to control and low fluences of 12.16 and 14.03 nm, respectively. These super hydrophilic surfaces in both cases reached higher cell viability with ∼13 and 34% increase, respectively, compared to unmodified PEEK, with an increased expression of alkaline phosphatase at 7 days on higher fluences establishing a higher affinity for preosteblasts with increased cellular activity, thus revealing successful and improved integration with the implant material, which can potentially be used in bone tissue engineering.

Peek screw displacement after PCL reconstruction: A radiographic red herring solved by MRI

Posterior cruciate ligament (PCL) repair has been increasingly performed as opposed to conservative management of PCL tears, in order to protect against future osteoarthrosis and meniscal degeneration. Fixation of the graft to bone can be done with interference screws, of which those composed of a bioresorbable material such as polyetheretherketone (PEEK) are preferred, owing to their inertness, good fixation strength and superior MR imaging compatibility. However, PEEK screws (unlike titanium screws) are radiolucent, and can make accurate post-operative evaluation by radiographs challenging. This is the first reported case of loosening of PEEK screw post-PCL repair, which highlights the importance of MRI and potential pitfall of radiography in evaluating post-surgical ligament laxity.