Mauricio Kfuri

Biomechanical Comparison of Five Posterior Cruciate Ligament Reconstruction Techniques

Abstract No surgical technique recreates native posterior cruciate ligament (PCL) biomechanics. We compared the biomechanics of five different PCL reconstruction techniques versus the native PCL. Cadaveric knees (n = 20) were randomly assigned to one of five reconstruction techniques: Single bundle all‐inside arthroscopic inlay, single bundle all‐inside suspensory fixation, single bundle arthroscopic‐assisted open onlay (SB‐ONL), double bundle arthroscopic‐assisted open inlay (DB‐INL), and double bundle all‐inside suspensory fixation (DB‐SUSP). Each specimen was potted and connected to a servo‐hydraulic load frame for testing in three conditions: PCL intact, PCL deficient, and PCL reconstructed. Testing consisted of a posterior force up to 100 N at a rate of 1 N/s at four knee flexion angles: 10, 30, 60, and 90 degrees. Three material properties were measured under each condition: load to 5 mm displacement, maximal displacement, and stiffness. Data were normalized to the native PCL, compared across techniques, compared with all PCL‐intact knees and to all PCL‐deficient knees using one‐way analysis of variance. For load to 5 mm displacement, intact knees required significantly (p < 0.03) more load at 30 degrees of flexion than all reconstructions except the DB‐SUSP. At 60 degrees of flexion, intact required significantly (p < 0.01) more load than all others except the SB‐ONL. At 90 degrees, intact, SB‐ONL, DB‐INL, and DB‐SUSP required significantly more load (p < 0.05). Maximal displacement testing showed the intact to have significantly (p < 0.02) less laxity than all others except the DB‐INL and DB‐SUSP at 60 degrees. At 90 degrees the intact showed significantly (p < 0.01) less laxity than all others except the DB‐SUSP. The intact was significantly stiffer than all others at 30 degrees (p < 0.03) and 60 degrees (p < 0.01). Finally, the intact was significantly (p < 0.05) stiffer than all others except the DB‐SUSP at 90 degrees. No technique matched the exact properties of the native PCL, but the double bundle reconstructions more closely recreated the native biomechanics immediately after implantation, with the DB‐SUSP coming closest to the native ligament. This study contributes new data for consideration in PCL reconstruction technique choice.

Biomechanical Comparison: Single-Bundle versus Double-Bundle Posterior Cruciate Ligament Reconstruction Techniques

&NA; Controversy exists regarding double‐bundle (DB) versus single‐bundle (SB) posterior cruciate ligament (PCL) reconstruction, with differences in multiple variables affecting biomechanical and clinical results. Our objective was to compare immediate postimplantation biomechanics of SB versus DB reconstructions to determine the relative importance of restoring both PCL bundles versus total graft volume. Twenty knees were randomly assigned to five techniques (n = 4 knees/technique), performed by three surgeons experienced in their technique(s), three SB techniques (n = 12; all‐inside arthroscopic inlay, all‐inside suspensory fixation, and arthroscopic‐assisted open onlay), and two DB techniques (n = 8; arthroscopic‐assisted open inlay and all‐inside suspensory fixation). Each knee was tested in three conditions: PCL‐intact, PCL‐deficient, and post‐PCL reconstruction. Testing consisted of a posterior‐directed force at four knee flexion angles, 10, 30, 60, and 90 degrees, to measure load to 5 mm of posterior displacement, maximum displacement (at 100 N load), and stiffness. Data for each knee were normalized, combined into two groups (SB and DB), and then compared using one‐way analysis of variance. Graft volumes were calculated and analyzed to determine if differences significantly influenced the biomechanical results. Intact knees were stiffer than both groups at most angles (p < 0.02; p < 0.05). DB was stiffer than SB at all angles except 30 degrees (p < 0.05). Intact knees had less laxity than SB (p < 0.03) and DB (p < 0.05) at 60 and 90 degrees. DB had less laxity than SB at all angles except 60 degrees (p < 0.05). Intact knees required more load than SB at 30, 60, and 90 degrees (p < 0.01) and more than DB at 60 and 90 degrees (p < 0.05). DB required more load than SB at 30, 60, and 90 degrees (p < 0.01). Graft volumes did not have strong correlations (r = 0.13–0.37) to any measurements. Neither group of PCL reconstruction techniques was able to replicate native PCL biomechanics. DB reconstructions were biomechanically superior to SB reconstructions; they may be preferred for clinical use when immediate post‐reconstruction graft strength and stability are critical. These results were not strongly influenced by graft size differences, further supporting the PCL codominance theory.

Extended Anterolateral Approach for Complex Lateral Tibial Plateau Fractures

Abstract Complex fractures of the lateral tibial plateau may extend to the posterior rim of the knee and to the tibial spines. Displaced fractures of the posterolateral corner of the tibial plateau may result in joint incongruity and instability, especially with the knee in flexion. Anatomical reduction of the joint surface and containment of the tibial rim are the primary goals of the treatment in such cases. Dedicated surgical approaches including dissection of the peroneal nerve, sometimes in association with an osteotomy of the fibular head are typically used to address these injuries. Some techniques require special positioning of the patient on the operative table. Anatomical studies of the knee allowed us to conclude that an osteotomy of the lateral epicondyle of the femur may be a natural extension of the standard anterolateral approach to the tibial plateau. The main advantage of this approach is the broad exposure of the lateral joint surface, allowing its anatomical reduction. It does not violate the proximal tibiofibular joint or pose a risk to the peroneal nerve. The main limitation is the lack of visualization of the posterior metaphysis of the tibia, preventing the application of a buttress plate parallel to the plane of fracture split. To overcome this limitation, we describe a method to support the posterior tibial plateau rim, in cases of bicondylar tibial plateau fractures, combining the extended anterolateral with the posteromedial approach. For selected cases, with a significant compromise of the posterolateral and anterolateral quadrants of the tibial plateau, including the tibial spines, the extended anterolateral approach may be complemented by a planned detachment of the anterior horn of the lateral meniscus. In such variant, a complete exposure of the entire surface of the lateral tibial plateau and tibial spines is achievable, assuring optimal conditions for an anatomical reduction of the articular surface.

The relationship between performance on the modified star excursion balance test and the knee muscle strength before and after anterior cruciate ligament reconstruction

OBJECTIVES The objective of this study was to evaluate the dynamic balance of the injured and uninjured limb before and after the anterior cruciate ligament (ACL) reconstruction and compare with the control group. STUDY DESIGN Prospective longitudinal. SETTING Biomechanics laboratory. PARTICIPANTS Participants are 24 males (mean age, 27.5 years) with unilateral ACL injury (ACLG) and 24 male healthy volunteers (CG). MAIN OUTCOMES MEASURES The modified star excursion balance test (SEBT) and isokinetic knee extensor and flexor strength were applied in the ACLG preoperatively and after surgery. The dominant limb of CG was evaluated at a single time. RESULTS There was no difference between the injured and the uninjured limb of the ACLG (P > 0.05) before and after surgery. Preoperatively, both ACLG limbs had a significantly lower reach distance in posteromedial (PM) and posterolateral (PL) directions and in composite reach (CR) score compared to the control group (P < 0.001). Postoperatively, no significant differences were found between ACLG and CG (P > 0.05). There was a positive correlation between preoperative PL (0.59) and CR (0.51), postoperative PM (0.36), PL (0.36) and CR (0.46) with flexor strength at 12 months after surgery. CONCLUSION Patients with ACL injury presented a worse performance in the SEBT in the preoperative period compared to the control group. After ligament reconstruction, the performance in the SEBT became equivalent to that of the control group. The strong correlation between flexor strength and posterior directions of the injured limb demonstrates the importance of the knee flexor muscles in the neuromuscular control of patients submitted to ACL reconstruction.

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures

&NA; Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane‐oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two‐dimensional videos of computed tomography, and three‐dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter‐ and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi‐square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker (p < 0.01). The addition of computed tomography scans to plain radiographs improved the interobserver reliability of Schatzker classification. Computed tomography had a statistically significant impact in the selection of surgical approaches for the lateral tibial plateau.

Algorithmic treatment of Busch-Hoffa distal femur fractures: A technical note based on a modified Letenneur classification

Treatment of distal femur fractures in the coronal plane can be challenging. Depending on fracture line orientation, topography and associated comminution, decision-making regarding approach and fixation is not straightforward and can result in complications. Therefore, treatment of coronal plane distal femur fractures (Busch-Hoffa fractures) should be approached in a systematic manner, leading to efficient planning and operative execution. Here, we offer a proposed treatment algorithm, guiding treatment, approach and fixation based on the modified Letenneur classification of coronal plane distal femur fractures.

Comparison of Platelet Rich Plasma and Bone Marrow Aspirate Concentrate for Osteoprogenitor Cell Retention and Osteoinductive Potential for Osteochondral Allograft

Objectives: Osteochondral allograft (OCA) transplantation is effective for treatment of large articular defects in the knee, hip, ankle, and shoulder of athletes. While success after OCA transplantation is good, one mechanism of failure involves inintegration of OCA bone into recipient bone. Because the OCA bone is devoid of viable cells and blood supply at implantation, and is allogeneic, integration is dependent upon cellular repopulation and neovascularization via creeping substitution. Enhancing this process using bone marrow aspirate concentrate (BMAC) or platelet rich plasma (PRP) could minimize graft failures and improve patient outcomes. Therefore, this study was designed to test the hypothesis that BMAC would be associated with superior viable osteoprogenitor cell repopulation of OCAs and osteoinductive protein production compared to PRP and saline using an ex vivo model. Methods: With ACUC approval, BMAC and leukoreduced PRP were processed from BMA (proximal humerus) and whole blood (jugular vein), respectively, of adult dogs using a commercially available system. Femoral condyles were harvested from adult dogs (n=3) immediately after euthanasia for unrelated reasons and preserved using tissue bank protocol. On day 21 of preservation, cylindrical OCAs (8 mm diam x 8 mm depth) were created (n=36; 12/dog), and randomly assigned to treatments: (1) NEG - bone portion of OCA lavaged with 10 ml saline (2) BMAC - bone portion of OCA lavaged, dried, and then saturated with 0.5 ml BMAC (3) PRP - bone portion of OCA lavaged, dried, and then saturated with 0.5 ml PRP. OCAs were cultured for 7 or 14 days (n=6/group/day), media were changed and collected on days 3, 7, and 14 for biomarker analysis. On days 7 and 14, OCAs were evaluated for viable cell colonization and infiltration using Calcein AM staining. To determine if cells were osteoprogenitors, colony forming unit (CFU) analysis was performed using crystal violet staining to determine CFUs/ml for each BMAC and PRP sample. OCA culture media were assessed for alkaline phosphatase (ALP), dickkopf-related protein (DKK), osteoprotegerin (OPG), osteopontin (OPN), adrenocorticotropic hormone (ACTH), bone morphogenic protein-2 (BMP-2), and bone morphogenic protein-7 (BMP-7) using commercially available assays. Data were compared for statistically significance (p≤0.05) differences. Results: For all BMAC OCAs, viable cells were present on the surface and deep areas of the bone at days 7 and 14. Viable cells were not observed in any part of the bone of PRP or NEG OCAs at either time point (Fig). BMAC samples had a significantly higher (p=0.029) CFU/ml compared to PRP. Concentrations of OPG were significantly higher in BMAC and PRP compared to NEG at days 3 (p<0.001) and 7 (p≤0.004). The concentration of DKK was significantly (p=0.038) higher in BMAC compared to NEG at day 3. Concentrations of BMP-2 were significantly higher in BMAC at days 3 (p<0.001) and 7 (p=0.017) and PRP at day 3 (p=0.009) compared to NEG. The concentration of ALP was significantly lower in PRP compared to NEG at day 3 (p=0.03). Concentrations of BMP-7 and OPN were below detectable limits of the assay for all groups and time points. Conclusion: BMAC showed superior viable osteoprogenitor cell repopulation of OCAs and osteoinductive protein production compared to PRP and the current standard-of-care (saline). BMAC has potential to enhance integration of osteochondral allograft bone and to improve graft survivorship and patient outcomes. Figure Viable (green staining) osteoprogenitor cells on OCAs treated with BMAC, PRP or saline on days 7 and 14 of culture

OCA Transplantation Outcomes for Replacing Large Bipolar Defects in the Knee using Novel Techniques

Objectives: Osteochondral allograft (OCA) transplantation can functionally restore large articular cartilage defects in the knee, shoulder, hip and ankle. Studies have reported 10-year survivorship between 71% and 85% and up to 74% survivorship at 15 years. Outcomes after OCA treatment have been good to excellent, even in the athletic population in which 88% of patients returned to sport, including 79% returning to preinjury level of sport. However, OCA transplantations for bipolar defects in the knee have traditionally had less favorable results. With the advent of improved allograft preservation methods and refined surgical techniques, OCA transplantations for bipolar defects in the knee have shown a trend toward better outcomes. Therefore, the objective of this study was to report early functional outcomes associated with OCA transplantations to replace large (>4 cm2) bipolar articular cartilage defects in the knee using novel techniques for graft preservation, enhancing bone ingrowth, and implantation. Methods: With IRB approval, patients were enrolled in a dedicated registry for prospective assessment of outcomes after OCA surgery. Demographic and operative data were collected. Outcomes assessments including VAS pain, VAS level of function, IKDC, SANE and PROMIS Mobility are prospectively collected at 6 months and yearly after surgery. All complications and re-operations are recorded. OCA survival is determined based on maintenance of acceptable levels of pain and function and/or need for revision surgery. Data are compared to pre-operative and/or pre-injury levels using repeated measures analyses with significance set at p<0.05. Results: Large bipolar OCA transplantations were performed in 23 knees: femorotibial (n=19), patellofemoral (n=4). Mean age of patients was 34.6 years. Mean pre-operative pain, function, IKDC, SANE and PROMIS Mobility scores were 4.7, 4.1, 40.8, 40.1 and 42.1, respectively. At 6 months postop (n=17), mean scores improved to 1.3, 6, 56.2, 71.8 and 46.1, respectively. At 1 year (n=11), mean scores further improved to 0.4, 8.4, 76.7, 80.6 and 58.4, respectively (Table). Two (8.7%) meniscotibial grafts failed in the first 6 months after surgery and were successfully revised by a second OCA transplantation, making initial survival 91.3%. Five (21.7%) other patients required minor reoperations for lysis of adhesions to restore range of motion and/or screw removal. All subjects are enrolled in the registry and outcomes assessments are ongoing and will be updated for presentation. Conclusion: Bipolar osteochondral allograft transplantation surgeries for treatment of large (>4 cm2) femorotibial or patellofemoral articular cartilage defects in the knee using novel techniques are associated with significant improvements in levels of pain and function at 1 year after surgery. Table – Summary of Outcomes for Large Bipolar OCA Transplantation in Knees Time Point Pain Function IKDC SANE PROMIS Mobility Pre-Operative 4.7 4.1 40.8 40.1 42.1 6 months 1.3* 6.0 56.2 71.8* 46.1 1 year 0.4* 8.4* 76.7* 80.6* 58.4* * denotes statistically significant (p<0.05) improvement from pre-op

Erratum: A Simple Technique to Prevent Early or Late EndoButton Deployment in Anterior Cruciate Ligament Reconstructions: A Technical Note

The use of suspensory graft fixation methods in arthroscopic reconstruction of the anterior cruciate ligament has become increasingly popular with the more frequent use of tendon grafts and anatomical techniques involving the creation of bone tunnels. An important technical step to ensure adequate fixation of the graft when using EndoButton-type implants, particularly in the femur, involves flipping the EndoButton plate at the correct length to avoid performing this maneuver before the appropriate time or leaving soft tissue between the plate and lateral cortex of the femur. In the present study, we describe a simple arthroscopic technique for indicating the correct time to flip/deploy the EndoButton plate.

Tibial Onlay Posterior Cruciate Ligament Reconstruction: Surgical Technique and Results

Abstract The posterior cruciate ligament (PCL) is a fundamental structure in knee kinematics. PCL tears may lead to adverse consequences, such as impaired functional performance and an increased risk of osteoarthritis. Although surgical treatment is a well‐established option for the patients of PCL rupture, many surgeons opt for conservative treatment because of the lack of consensus in the orthopedic literature concerning the best surgical method with less risk of iatrogenic lesions to the neurovascular structures in the popliteal region. Here, we describe an onlay technique for PCL reconstruction, which has some advantages over the traditional transtibial and over inlay techniques. The technique described in this study avoids the “killer angle”—frequently considered the cause of laxity of the reconstructed ligament—while simultaneously permitting safe retraction of the neurovascular structures without the need for a change in the patients position. This technique has been used at our institution for approximately 10 years with very satisfactory results. The aim of this study is to describe the technique and perform a retrospective evaluation of the results of a case series.