The forgotten joint: quantifying the anatomy of the proximal tibiofibular joint.

PURPOSE: Limited objective data exist detailing the quantitative anatomy of the individual bundles of the proximal tibiofibular joint and their relation to surgically pertinent osseous landmarks. The purpose of this study was to qualitatively and quantitatively describe the ligamentous anatomy of the proximal tibiofibular joint and its relation to relevant bony landmarks. METHODS: Ten non-paired, fresh-frozen cadaveric knee specimens were dissected to identify the proximal tibiofibular joint ligament bundles. Pertinent bony landmarks were identified and served as reference points for the tibial and fibular attachments for each bundle. Ligament bundle footprints, lengths and orientations were measured using a 3D coordinate measuring device. RESULTS: Up to four bundles were identified anteriorly and up to three bundles posteriorly. The inferior bundle was identified anteriorly and posteriorly in 60% and 20% of the cases, respectively. For the anterior complex, the centres of the tibial attachments were a mean distance of 12.5 mm (95% CI [10.7, 14.3]) and 25.3 mm (95% CI [21.6, 29.0]) from the tibial plateau for the superior and inferior bundles, respectively. The centres of the fibular attachments were 11.3 mm (95% CI [7.4, 15.1]) and 27.0 mm (95% CI [24.0, 30.0]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. For the bundles of the posterior complex, the centres of the tibial attachments were 13.4 mm (95% CI [11.6, 15.2]) and 38.8 mm (95% CI [31.0, 46.6]) distal to the tibial plateau for the superior and inferior bundles, respectively, and the centres of the fibular attachments were 8.0 mm (95% CI [5.8, 10.1]) and 29.3 mm (95% CI [25.5, 33.1]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. In the coronal plane, the mean 2D angle between the medial to lateral knee joint axis and the axis passing through the centre of the proximal tibiofibular joint and the centre of the tibial plateau was 16.9° (95% CI [12.8, 21.0]). CONCLUSION: The ligament bundles of the proximal tibiofibular joint were reproducibly identified between specimens in relation to surrounding bony landmarks. Up to four bundles were identified in the anterior ligament complex and up to three in the posterior complex. Variation in bundle orientation and footprint size was observed. Based on these findings, an anatomic reconstruction can be performed using surrounding reliable landmarks.

Quantitative radiographic assessment of the anatomic attachment sites of the anterior and posterior complexes of the proximal tibiofibular joint.

PURPOSE: Quantitative guidelines for radiographic identification of the anterior and posterior ligaments of the proximal tibiofibular joint have not been well defined. The purpose of this study was to provide reproducible, quantitative descriptions of radiographic landmarks identifying the anterior and posterior ligament complexes of the proximal tibiofibular joint. It was hypothesized that consistent quantitative data regarding the radiographic location of the anterior and posterior proximal tibiofibular joint ligament complexes could be identified. METHODS: The footprint centers of the individual ligament bundles of the anterior and posterior complexes of the proximal tibiofibular joint were labeled with radio-opaque markers in ten non-paired, fresh-frozen cadaveric knee specimens. Anteroposterior (AP) and lateral radiographs of the proximal tibiofibular joint were obtained, and distances between the markers and pertinent radiographic landmarks were recorded. RESULTS: On AP radiographs, the tibial span of the anterior complex was 12.8 ± 3.9 mm and started at a median of 11.4 mm distal to the tibial plateau; the fibular span was 11.6 ± 6.8 mm and started at a median of 5.1 mm from the apex of the fibular styloid. The tibial span of the posterior complex was 11.7 ± 8.4 mm and began at a median of 12.1 mm distal to the tibial plateau; the fibular span was 11.8 ± 7.9 mm and began at a median of 3.1 mm distal to the apex of the fibular styloid. Values were similar for lateral radiographs. CONCLUSION: The attachment locations of the proximal tibiofibular anterior and posterior complexes could be quantitatively correlated to reliable osseous landmarks and radiographic lines. This information will allow for consistent radiographic assessments of proper tunnel placement intraoperatively and postoperatively during anatomic reconstructions of the proximal tibiofibular joint.

Arthroscopic Reconstruction of the Ligamentum Teres: A Guide to Safe Tunnel Placement.

PURPOSE: To provide a quantitative guide to tunnel placement concurrently through the femur and acetabulum during a ligamentum teres reconstruction, minimizing the risk of injury to the obturator neurovascular bundle. METHODS: Nine human cadaveric pelvises, complete with femurs (mean age, 59.6 years; age range, 47-65 years), were studied. Before dissection, a 3-dimensional coordinate-measuring device was used to record the neutral orientation of the femur in the acetabulum. The specimens were then dissected free of all extra-articular soft tissue, except for the ligamentum teres and the obturator neurovascular bundle, and digitized. An anatomic femoral reconstruction tunnel through the femoral neck was simulated and extended along its axis into the acetabulum. The femur was digitally rotated internally from 0° to 30° and externally from 0° to 40°, as well as abducted from 0° to 30° and adducted from 0° to 20°, in increments of 1°. At each position, the location of the simulated acetabular reconstruction tunnel was measured with respect to the obturator bundle and the edge of the acetabular fossa. RESULTS: The anatomic reconstruction tunnel entered the lateral side of the femur at a mean distance of 7.0 mm distal and 5.8 mm anterior to the center of the vastus ridge. By angling the femur at 15° of internal rotation and 15° of abduction, the obturator neurovascular bundle was avoided in 100% of specimens. CONCLUSIONS: The most important finding of this study was that a ligamentum teres reconstruction tunnel could be reamed through the femoral neck and safely positioned in the acetabulum by angling the femur at 15° of internal rotation and 15° of abduction. CLINICAL RELEVANCE: These quantitative descriptions of the ligamentum teres reconstruction tunnels can be used to guide arthroscopic surgical interventions designed to address ligamentum teres pathology.

Intraarticular arthrofibrosis of the knee alters patellofemoral contact biomechanics.

BACKGROUND: Arthrofibrosis in the suprapatellar pouch and anterior interval can develop after knee injury or surgery, resulting in anterior knee pain. These adhesions have not been biomechanically characterized. METHODS: The biomechanical effects of adhesions in the suprapatellar pouch and anterior interval during simulated quadriceps muscle contraction from 0 to 90° of knee flexion were assessed. Adhesions of the suprapatellar pouch and anterior interval were hypothesized to alter the patellofemoral contact biomechanics and increase the patellofemoral contact force compared to no adhesions. RESULTS: Across all flexion angles, suprapatellar adhesions increased the patellofemoral contact force compared to no adhesions by a mean of 80 N. Similarly, anterior interval adhesions increased the contact force by a mean of 36 N. Combined suprapatellar and anterior interval adhesions increased the mean patellofemoral contact force by 120 N. Suprapatellar adhesions resulted in a proximally translated patella from 0 to 60°, and anterior interval adhesions resulted in a distally translated patella at all flexion angles other than 15° (p < 0.05). CONCLUSIONS: The most important finding in this study was that patellofemoral contact forces were significantly increased by simulated adhesions in the suprapatellar pouch and anterior interval. Anterior knee pain and osteoarthritis may result from an increase in patellofemoral contact force due to patellar and quadriceps tendon adhesions. For these patients, arthroscopic lysis of adhesions may be beneficial.

A Contact Pressure Analysis Comparing an All-Inside and Inside-Out Surgical Repair Technique for Bucket-Handle Medial Meniscus Tears.

PURPOSE: To directly compare effectiveness of the inside-out and all-inside medial meniscal repair techniques in restoring native contact area and contact pressure across the medial tibial plateau at multiple knee flexion angles. METHODS: Twelve male, nonpaired (n = 12), fresh-frozen human cadaveric knees underwent a series of 5 consecutive states: (1) intact medial meniscus, (2) MCL tear and repair, (3) simulated bucket-handle longitudinal tear of the medial meniscus, (4) inside-out meniscal repair, and (5) all-inside meniscal repair. Knees were loaded with a 1,000-N axial compressive force at 5 knee flexion angles (0°, 30°, 45°, 60°, 90°), and contact area, mean contact pressure, and peak contact pressure were calculated using thin film pressure sensors. RESULTS: No significant differences were observed between the inside-out and all-inside repair techniques at any flexion angle for contact area, mean contact pressure, and peak contact pressure (all P > .791). Compared with the torn meniscus state, inside-out and all-inside repair techniques resulted in increased contact area at all flexion angles (all P < .005 and all P < .037, respectively), decreased mean contact pressure at all flexion angles (all P < .007 and all P < .001, respectively) except for 0° (P = .097 and P = .39, respectively), and decreased peak contact pressure at all flexion angles (all P < .001, all P < .001, respectively) except for 0° (P = .080 and P = .544, respectively). However, there were significant differences in contact area and peak contact pressure between the intact state and inside-out technique at angles ≥45° (all P < .014 and all P < .032, respectively). Additionally, there were significant differences between the intact state and all-inside technique in contact area at 60° and 90° and peak contact pressure at 90° (both P < .005 and P = .004, respectively). Median values of intact contact area, mean contact pressure, and peak contact pressure over the tested flexion angles ranged from 498 to 561 mm2, 786 to 997 N/mm2, and 1,990 to 2,215 N/mm2, respectively. CONCLUSIONS: Contact area, mean contact pressure, and peak contact pressure were not significantly different between the all-inside and inside-out repair techniques at any tested flexion angle. Both techniques adequately restored native meniscus biomechanics near an intact level. CLINICAL RELEVANCE: An all-inside repair technique provided similar, native-state-restoring contact mechanics compared with an inside-out repair technique for the treatment of displaced bucket-handle tears of the medial meniscus. Thus, both techniques may adequately decrease the likelihood of cartilage degeneration.

Lateral Meniscus Posterior Root and Meniscofemoral Ligaments as Stabilizing Structures in the ACL-Deficient Knee: A Biomechanical Study.

BACKGROUND: The biomechanical effects of lateral meniscal posterior root tears with and without meniscofemoral ligament (MFL) tears in anterior cruciate ligament (ACL)-deficient knees have not been studied in detail. PURPOSE: To determine the biomechanical effects of the lateral meniscus (LM) posterior root tear in ACL-intact and ACL-deficient knees. In addition, the biomechanical effects of disrupting the MFLs in ACL-deficient knees with meniscal root tears were evaluated. STUDY DESIGN: Controlled laboratory study. METHODS: Ten paired cadaveric knees were mounted in a 6-degrees-of-freedom robot for testing and divided into 2 groups. The sectioning order for group 1 was (1) ACL, (2) LM posterior root, and (3) MFLs, and the order for group 2 was (1) LM posterior root, (2) ACL, and (3) MFLs. For each cutting state, displacements and rotations of the tibia were measured and compared with the intact state after a simulated pivot-shift test (5-N·m internal rotation torque combined with a 10-N·m valgus torque) at 0°, 20°, 30°, 60°, and 90° of knee flexion; an anterior translation load (88 N) at 0°, 30°, 60°, and 90° of knee flexion; and internal rotation (5 N·m) at 0°, 30°, 60°, 75°, and 90°. RESULTS: Cutting the LM root and MFLs significantly increased anterior tibial translation (ATT) during a pivot-shift test at 20° and 30° when compared with the ACL-cut state (both Ps < .05). During a 5-N·m internal rotation torque, cutting the LM root in ACL-intact knees significantly increased internal rotation by between 0.7° ± 0.3° and 1.3° ± 0.9° (all Ps < .05) except at 0° (P = .136). When the ACL + LM root cut state was compared with the ACL-cut state, the increase in internal rotation was significant at greater flexion angles of 75° and 90° (both Ps < .05) but not between 0°and 60° (all Ps > .2). For an anterior translation load, cutting the LM root in ACL-deficient knees significantly increased ATT only at 30° (P = .007). CONCLUSION: The LM posterior root was a significant stabilizer of the knee for ATT during a pivot-shift test at lower flexion angles and internal rotation at higher flexion angles. CLINICAL RELEVANCE: Increased knee anterior translation and rotatory instability due to posterior lateral meniscal root disruption may contribute to increased loads on an ACL reconstruction graft. It is recommended that lateral meniscal root tears be repaired at the same time as an ACL reconstruction to prevent possible ACL graft overload.

Quantitative Anatomic Analysis of the Native Ligamentum Teres.

BACKGROUND: While recent studies have addressed the biomechanical function of the ligamentum teres and provided descriptions of ligamentum teres reconstruction techniques, its detailed quantitative anatomy remains relatively undocumented. Moreover, there is a lack of consensus in the literature regarding the number and morphology of the acetabular attachments of the ligamentum teres. PURPOSE: To provide a clinically relevant quantitative anatomic description of the native human ligamentum teres. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten human cadaveric hemipelvises, complete with femurs (mean age, 59.6 years; range, 47-65 years), were dissected free of all extra-articular soft tissues to isolate the ligamentum teres and its attachments. A coordinate measuring device was used to quantify the attachment areas and their relationships to pertinent open and arthroscopic landmarks on both the acetabulum and the femur. The clock face reference system was utilized to describe acetabular anatomy, and all anatomic relationships were described using the mean and 95% confidence intervals. RESULTS: There were 6 distinct attachments to the acetabulum and 1 to the femur. The areas of the acetabular and femoral attachment footprints of the ligamentum teres were 434 mm2 (95% CI, 320-549 mm2) and 84 mm2 (95% CI, 65-104 mm2), respectively. The 6 acetabular clock face locations were as follows: anterior attachment, 4:53 o'clock (95% CI, 4:45-5:02); posterior attachment, 6:33 o'clock (95% CI, 6:23-6:43); ischial attachment, 8:07 o'clock (95% CI, 7:47-8:26); iliac attachment, 1:49 o'clock (95% CI, 1:04-2:34); and a smaller pubic attachment that was located at 3:50 o'clock (95% CI, 3:41-4:00). The ischial attachment possessed the largest cross-sectional attachment area (127.3 mm2; 95% CI, 103.0-151.7 mm2) of all the acetabular attachments of the ligamentum teres. CONCLUSION: The most important finding of this study was that the human ligamentum teres had 6 distinct points of attachment on the acetabulum (transverse, anterior, and posterior margins of the acetabular notch and cotyloid fossa attachments: ilium, ischium, and pubis) and 1 on the femur. On the acetabulum, the anterior attachment was substantially larger than the posterior attachment and was located at a mean clock face position of 4:53 o'clock. CLINICAL RELEVANCE: These quantitative descriptions of the ligamentum teres can be used by clinicians to arthroscopically identify the attachments of the ligamentum teres, guiding arthroscopic surgical interventions designed to address ligamentum teres pathology.

Effect of Suture Caliber and Number of Core Strands on Repair of Acute Achilles Ruptures: A Biomechanical Study.

BACKGROUND: Controversy exists regarding the ideal Achilles rupture treatment; however, operative treatment is considered for athletes and active patients. The ideal repair construct is evolving, and the effect of suture caliber or number of core strands has not been studied. METHODS: Simulated mid-substance Achilles ruptures were performed in 24 cadavers. Specimens were randomized to three 6-core-strand style repair constructs: (1) 4 No. 2 sutures and two 2-mm tapes (2T); (2) 2 No. 2 sutures and four 2-mm tapes (4T); (3) 12 (double-6-strand) strand repair (12 No. 2-0 sutures [12S]). Repairs were subjected to a cyclic loading protocol representative of postoperative rehabilitation. These data were compared to a previously published standard open repair technique (6-core strands with No. 2 sutures) on 9 specimens tested under the same conditions.6 Results: No significant elongation differences were observed between the repair groups and the previously published standard repair group in the first 2 stages of the simulated rehabilitation protocol. Both the 2T and 12S repairs survived a significantly greater number of cycles to failure ( P = 0.0005, P = 0.0267, respectively) and had a significantly higher failure load ( P = .0005, P = .0118, respectively) compared to the previously published data. These 2 constructs consistently survived the advanced stages of the simulated rehabilitation protocol. The majority of repairs failed at the knots. CONCLUSIONS: In this study, the 2T and 12S constructs survived the later stages of our simulated rehabilitation protocol, suggesting that they may be able to accommodate a more aggressive clinical rehabilitation protocol. Substituting suture-tape for 2 core strands or doubling the core strands with a smaller-caliber suture created a biomechanically stronger construct. CLINICAL RELEVANCE: Achilles repair with an added nonabsorbable, high-tensile strength tape allowed for a stronger construct that may allow for a more aggressive, early rehabilitation protocol and earlier return to function.

Multiple Ligament Reconstruction Femoral Tunnels: Intertunnel Relationships and Guidelines to Avoid Convergence.

BACKGROUND: Knee dislocations often require multiple concurrent ligament reconstructions, which involve creating several tunnels in the distal femur. Therefore, the risk of tunnel convergence is increased because of the limited bone volume within the distal aspect of the femur. PURPOSE: To assess the risk of tunnel convergence and determine the optimal reconstruction tunnel orientations for multiple ligament reconstructions in the femur. STUDY DESIGN: Descriptive laboratory study. METHODS: Three-dimensional knee models were developed from computed tomography scans of 21 patients. Medical image processing software was used to create tunnels for each of the primary ligamentous structures, replicating a surgical approach that would be used in multiple ligament reconstructions. Thereafter, the tunnel orientation was varied in surgically relevant directions to determine orientations that minimized the risk of tunnel convergence. The orientation of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tunnels was held constant throughout the study, while the orientation of the fibular collateral ligament (FCL), popliteus tendon (PLT), superficial medial collateral ligament (sMCL), and posterior oblique ligament (POL) tunnels was varied to avoid convergence. RESULTS: A high risk of tunnel convergence was observed between the FCL and ACL tunnels when the FCL tunnel was aimed at 0° in the axial and coronal planes. Aiming the FCL tunnel 35° anteriorly minimized convergence with the ACL tunnel. No tunnel convergence was observed for the PLT tunnel aimed 35° anteriorly and parallel to the FCL tunnel. To avoid convergence between the sMCL and PCL tunnels, the sMCL tunnels should be aimed 40° proximally in the coronal plane and 20° to 40° anteriorly. During concomitant POL reconstruction, the sMCL should be aimed 40° proximally and anteriorly and the POL 20° proximally and anteriorly. The PLT and POL tunnels aimed at 0° in both the coronal and axial planes had an increased risk of violating the intercondylar notch. CONCLUSION: Femoral tunnel orientations during multiple ligament reconstructions need to be adjusted to avoid tunnel convergence. On the lateral side, aiming the FCL and PLT tunnels 35° anteriorly eliminated convergence with the ACL tunnel. On the medial side, tunnel convergence was avoided by orienting the sMCL tunnel 40° proximally and anteriorly and the POL tunnel 20° proximally and anteriorly. The POL and PLT tunnels aimed at 0° in the axial plane had an increased risk of violating the intercondylar notch. CLINICAL RELEVANCE: The risk of tunnel convergence with the ACL and PCL femoral tunnels can be reduced by adjusting the orientation of the FCL and PLT tunnels and the sMCL and POL tunnels, respectively.

Treatment of Midshaft Clavicle Fractures: Application of Local Autograft With Concurrent Plate Fixation.

Currently, open reduction-internal fixation using contoured plates or intramedullary nails is considered the standard operative treatment for midshaft clavicle fractures because of the immediate rigid stability provided by the fixation device. In addition, autologous iliac crest bone graft has proved to augment osteosynthesis during internal fixation of nonunion fractures through the release of osteogenic factors. The purpose of this article is to describe a surgical technique developed to reduce donor-site morbidity and improve functional and objective outcomes after open reduction-internal fixation with autologous bone graft placement through local autograft harvesting and concurrent plate fixation.

Intertunnel Relationships in the Tibia During Reconstruction of Multiple Knee Ligaments: How to Avoid Tunnel Convergence.

BACKGROUND: Knee dislocations are rare but potentially devastating injuries, often involving tears of multiple knee ligaments. Several studies have reported improved clinical and functional outcomes with surgical management of torn knee ligaments compared with nonsurgical management. Most multiple ligament reconstruction techniques involve creating several tunnels for various reconstruction grafts, posing a risk of tunnel convergence in the proximal tibia. PURPOSE: To assess the risk of tunnel convergence and determine the optimal tunnel placement for the reconstruction of multiple ligaments in the tibia. STUDY DESIGN: Descriptive laboratory study. METHODS: Three-dimensional knee models were developed using customized software from computed tomography images of 21 patients. Mimics software was used to create tunnels for each of the 4 primary ligamentous structures, replicating a surgical approach that would be used in actual multiple ligament reconstruction surgery. The tunnel orientation was varied in anatomically relevant directions to find orientations that did not result in tunnel convergence. RESULTS: There was a high risk of tunnel convergence (66.7%) between the posterior cruciate ligament (PCL) and posterior oblique ligament (POL) tunnels when the POL tunnel was aimed toward the Gerdy tubercle as suggested in the literature. No tunnel convergence was observed when the POL tunnel was aimed 15 mm medial to the Gerdy tubercle. No tunnel convergence was observed between the anterior cruciate ligament (ACL) and POL. Tunnel convergence was observed between the PCL and superficial medial collateral ligament (sMCL) in 19.0% of cases when the sMCL tunnel was aimed transversely across the tibia. Aiming the sMCL tunnel transversely and directing 30° distally significantly increased the mean distance between the sMCL and PCL to 6.9 mm (P < .001), and no tunnel convergence was observed. No tunnel convergence was observed between the PCL and posterolateral corner tunnels or between the ACL and PCL tunnels. CONCLUSION: There is a high risk of tunnel convergence in the proximal tibia during the reconstruction of multiple knee ligaments. Aiming the POL tunnel 15 mm medial to the Gerdy tubercle and the sMCL tunnel transversely across the tibia (anterior to the fibula) and 30° distal to the horizontal plane reduces the risk of tunnel convergence. CLINICAL RELEVANCE: The tunnel orientation of the POL and sMCL on the tibia should be adjusted to avoid convergence with the PCL tunnel during multiple ligament knee reconstruction.

Biomechanical Results of Lateral Extra-articular Tenodesis Procedures of the Knee: A Systematic Review.

PURPOSE: To systematically review and compare biomechanical results of lateral extra-articular tenodesis (LET) procedures. METHODS: A systematic review was performed using the PubMed, Medline, Embase, and Cochrane databases. The search terms included the following: extraarticular, anterolateral, iliotibial, tenodesis, plasty, augmentation, procedure, reconstruction, technique, biomechanics, kinematic, robot, cadaver, knee, lateral tenodesis, ACL, Marcacci, Lemaire, Losee, Macintosh, Ellison, Andrews, Hughston, and Muller. The inclusion criteria were nonanatomic, in vitro biomechanical studies, defined as in vitro investigations of joint motion resulting from controlled, applied forces. RESULTS: Of the 10 included studies, 7 analyzed anterior tibial translation and reported that isolated LET procedures did not restore normal anterior stability to the anterior cruciate ligament (ACL)-deficient knee. Seven of the 8 studies analyzing tibial rotation reported a reduction in internal tibial rotation across various flexion angles in the ACL-deficient knee when compared with the native state. Five studies reported a reduction in intra-articular graft force with the addition of an LET. Two studies evaluated length change patterns, graft course, and total strain range and found that reconstruction techniques in which the graft attached proximal to the lateral epicondyle and coursed deep to the fibular collateral ligament were most isometric. CONCLUSIONS: In the ACL-deficient knee, LET procedures overconstrained the knee and restricted internal tibial rotation when compared with the native state. In addition, isolated LET procedures did not return normal anterior stability to the ACL-deficient knee but did significantly reduce anterior tibial translation and intra-articular graft forces during anteriorly directed loading. CLINICAL RELEVANCE: Combined injury to the ACL and anterolateral structures has been reported to exhibit greater anterolateral rotatory instability when compared with isolated ACL injuries. Despite the reported risk of joint over-constraint, consideration should be given to reconstructing the anterolateral structures and the ACL concurrently to maximally restore both anterior tibial translation and rotatory stability.