Effect of tibial tunnel diameter on femoral tunnel placement in transtibial single bundle ACL reconstruction.

PURPOSE: The purpose of this study was to identify the impact of tibial reamer size and placement on the position of femoral tunnel placement via a transtibial approach for anterior cruciate ligament (ACL) reconstruction. METHODS: Eight cadaveric knee specimens were fixed to a stationary table at 90° of flexion and neutral rotation. After removing the anterior capsule and patella, native joint anatomy was recorded with a digitizer (MicroScribe™; CNC Services, Amherst, VA) accurate to 0.05 mm. Tibial and femoral tunnels were drilled via a transtibial ACLR technique using the optimal tibial starting point described by Piasecki et al. On the tibial side, tunnels were drilled progressively with 6-, 7-, 8-, 9-, 10-, and 11-mm reamers. After each reaming, a beath pin was placed in the posterior aspect of the tibial tunnel, positioned relative to the native anatomic ACL femoral footprint, and digitized. Rhino software (McNeel, Seattle, WA) was used to geometrically determine the center of the native femoral footprint and measure in millimeters the relationship of this point with the femoral position achieved using a 7-mm offset femoral guide with each tibial tunnel size. The surface areas of each tibial and femoral insertion were measured using the insertional periphery data recorded with the digitizer. Statistical analysis of continuous variable data was performed with t tests; P values below 0.05 were deemed significant. RESULTS: The center of the femoral ACL footprint was reached with a 9-mm tibial tunnel in six knees, and with an 8-mm tunnel in two knees. A 6- or 7-mm tibial tunnel did not allow for anatomic positioning in any specimen, with femoral positioning significantly more superior than that achieved with a 9-, 10-, or 11-mm tibial tunnel (P < 0.01). The 6- and 7-mm tunnels produced errors of 4.6 ± 1.6 and 2.9 ± 0.5 mm, respectively. After use of the 11-mm tibial reamer, the average tibial tunnel length was 32.1 ± 2.6 mm. CONCLUSIONS: Limitations of a transtibial ACLR technique may result in non-anatomic femoral tunnel placement with tibial tunnel sizes smaller than 9 mm. However, tibial tunnels placed in the proximal entry position with at least a 9-mm tunnel size allowed anatomic femoral tunnel placement via a transtibial approach.

Histological and radiographic evaluation of three common tendon transfer techniques in an un-ossified bone porcine model: implications for early anterior tibialis tendon transfers in children with clubfeet.

PURPOSE: To compare the histological healing and radiographic effects of tendons transferred to ossified or unossified bone using different tendon fixation techniques. METHODS: Nine new-born piglets underwent bilateral tendon transfers to either the ossified boney calcaneal body or unossified apophysis. The tendons were fixed using metallic suture anchors, sutures alone or a bone tunnel. At six weeks of age, calcanei were harvested, radiologically imaged and then prepared for histology. A semi-quantitative aggregated scoring system with values ranging from 0 (poor) to 15 (excellent), was used to grade healing at the surgical enthesis and the apophyseal ossification was graded by five independent reviewers in triplicate using a modified (1 to 4) validated scoring system. RESULTS: Histologically, the cartilaginous transfers utilizing the tunnel and suture techniques also demonstrated the best average aggregated scores of entheses healing rivalling that measured in transfers using the classic bone tunnel technique (clinical benchmark), whereas suture anchor fixation demonstrated the worst healing in both the ossified and unossified samples. All three transfer techniques caused at least minor alterations in apophyseal ossification, with the most significant changes observed in the metallic suture anchor cohort. The tunnel and suture techniques demonstrated similar and more mild abnormalities in ossification. CONCLUSION: Tendon transfers to unossified bone heal histologically as well as transfers classically performed through tunnels in bone. Suture fixation or tunnel techniques appear radiographically and histologically superior to suture anchors in our newborn porcine model.

Treating periprosthetic joint infections as biofilms: key diagnosis and management strategies.

Considerable evidence suggests that microbial biofilms play an important role in periprosthetic joint infection (PJI) pathogenesis. Compared to free-floating planktonic bacteria, biofilm bacteria are more difficult to culture and possess additional immune-evasive and antibiotic resistance mechanisms, making infections harder to detect and eradicate. This article reviews cutting-edge advances in biofilm-associated infection diagnosis and treatment in the context of current PJI guidelines and highlights emerging technologies that may improve the efficacy and reduce costs associated with PJI. Promising PJI diagnostic tools include culture-independent methods based on sequence comparisons of the bacterial 16S ribosomal RNA gene, which offer higher throughput and greater sensitivity than culture-based methods. For therapy, novel methods based on disrupting biofilm-specific properties include quorum quenchers, bacteriophages, and ultrasound/electrotherapy. Since biofilm infections are not easily detected or treated by conventional approaches, molecular diagnostic techniques and next-generation antibiofilm treatments should be integrated into PJI clinical practice guidelines in the near future.

Effect of reamer design on posteriorization of the tibial tunnel during endoscopic transtibial anterior cruciate ligament reconstruction.

BACKGROUND: It is known that small alterations in tunnel positioning during anterior cruciate ligament (ACL) reconstruction significantly affect ACL length and tensioning patterns as well as alter force vectors and joint kinematics. PURPOSE: To compare the amount of inadvertent posteriorization of the ACL tibial tunnel anatomy during transtibial ACL femoral reaming in the "over-the-top" position with a full femoral reamer versus a half femoral reamer, in comparison to the native tibial ACL footprint. It is hypothesized that the half reamer will result in less distortion of tibial tunnel anatomy and improved anatomic footprint coverage. It is also hypothesized that the true center of the tibial ACL footprint lies more anterior than previously described. STUDY DESIGN: Controlled laboratory study. METHODS: Eight cadaveric knee specimens were securely fixed to a stationary table at 90° of flexion and neutral rotation. After removal of the anterior capsule and patella, native joint anatomy was precisely recorded with a digitizer accurate to 0.05 mm. Tibial and femoral tunnels were then drilled in the manner of transtibial ACL reconstructions using the optimal tibial starting point of 15.9 mm below the medial plateau and 9.8 mm posteromedial to the medial margin of the tibial tubercle. After the 11-mm tibial tunnel was drilled, femoral tunnels were first drilled with a 10-mm half-fluted reamer, followed by a 10-mm full reamer. Each tibial tunnel's location and geometry relative to the native ligamentous insertion sites and joint anatomy were digitized. RESULTS: Digitized measurements of ACL insertional anatomy demonstrated that the center of the native ACL tibial footprint was 2.0 ± 0.49 mm (range, 1.1-2.7 mm) anterior to the posterior aspect of the lateral meniscus' anterior horn. Use of the 10-mm full femoral reamer resulted in a tibial-articular aperture that had a posterior edge 4.35 mm more posterior (P = .049) and extra-anatomic (P = .006) than the footprint of the 10-mm half femoral reamer. CONCLUSION: Half-fluted reamers may be more advantageous for femoral tunnel reaming with a more oblique transtibial approach, as they result in less posterior tibial tunnel expansion than full reamers, possibly leading to improved graft function. Based on the digitized anatomy, the center of the tibial attachment site is anterior to the posterior aspect of the lateral mensicus's anterior horn, which has been traditionally described as the anatomic center. CLINICAL RELEVANCE: Use of half-fluted reamers for transtibial femoral tunnel reaming could lead to more anatomic tunnel placement and possibly improved graft mechanics after transtibial single-bundle ACL reconstruction.