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Lateral meniscal root tears associated with anterior cruciate ligament injury: classification and management (SS-70)
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ABSTRACTS
attempted ten consecutive tunnel placements. The deviation in the ten attempts was recorded, as was the difference between the eight investigators. The results showed that the anatomical insertion site on the tibia and femur was accurately arrived at in each case with only minimal deviations. In addition, 300 postoperative x-rays of navigated anterior cruciate ligament replacements were analyzed and the position of the tunnels evaluated. To provide a comparison, 300 non-navigated anterior cruciate ligament replacements were also assessed. Whereas in each of the navigated cases, with only two exceptions, it was possible to achieve the optimal tibial insertion site sagittally at 47% (⫾5%) as well as the dorsal margin of the femoral cortex in the 10 or 2 o’clock position ⫾30 minutes, the tendency could be demonstrated in the non-navigated cruciate ligaments to site the tibial tunnel too far in a dorsal direction (mean value 50%, ⫾3%) and to site the femoral tunnel too high at 11 or 1 o’clock ⫾30 minutes. Through the use of the navigator, it was possible to change over to the anteromedial portal technique when the anatomical area on the femoral insertion was not attained. This occurred distinctly less often with the non-navigated cruciate ligaments.
applied to the graft during ACL reconstruction, the mean AP translation was 3.0 ⫾ 1.1 mm (range, 1.5-4.5 mm). Mean AP translation was 2.3 ⫾ 1.0 mm (range, 1.0-4.0 mm) when 40 N of tension was applied and 1.6 ⫾ 1.0 mm (range, 0.5-3.0 mm) with 80 N of tension. Mean AP translation in the ACL deficient knees was significantly greater than in the intact knees (P ⬍ .00009) and in all 3 reconstruction conditions (P ⬍ .0001 when 20 N and 40 N of tension was applied and P ⬍ .0003 when 80 N was applied). Mean translation when 20 N of tension was applied was significantly greater than when 80 N of tension was applied (P ⬍ .02), but the difference between the 20-N and 40-N conditions did not reach statistical significance (P ⬎ .07). The difference between the 40-N and 80-N conditions was significant (P ⬍ .02). None of the reconstruction conditions were found to be significantly different from the intact knees (P ⬎ .40 at 20 N, P ⬎ .65 at 40 N, and P ⬎ .23 at 80 N). Conclusions: In a cadaver model, tensioning a soft tissue ACL graft to 80 N provides greater AP knee stability immediately after reconstruction than 40 N or 20 N of graft tension. Further clinical studies are needed to determine the effects of graft tensioning on long-term knee stability and patient outcomes.
Ju¨ rgen Eichhorn, M.D.
Jeffrey C. Easom, D.O., Vipool K. Goradia, M.D., Sara E. Pearson, Ph.D., William B. Wiley, M.D.
Anterior Cruciate Ligament Tensioning: KT-1000 Measurements After Anterior Cruciate Ligament Reconstruction and Tensioning (SS-68) Purpose: With the increased availability of different tensioning devices, much attention has been focused on the amount of tension that is placed on anterior cruciate ligament (ACL) grafts during ACL reconstruction. The goal of this study was to analyze the effect of applying different levels of tension during ACL reconstruction on anterior-posterior (AP) translation in cadaveric knees. Type of Study: Cadaveric analysis. Methods: The posterior tibial tendon was harvested in 7 cadaveric specimens and used in ACL reconstruction. AP translation was measured with a KT-1000 in the intact knees, after ACL resection, and after ACL reconstruction with the graft tensioned at 20 N, 40 N, and 80 N. Graft tension was applied and measured using the Linvatec Stress Equalization (SE) Graft Tensioning System (Largo, FL). A maximum manual KT-1000 anterior force was applied by a single examiner with each knee at 30° of knee flexion. Results: The average AP translation in the intact knees was 2.6 ⫾ 1.1 mm (range, 1.0-4.0 mm). The average AP translation after ACL resection was 6.2 ⫾ 1.3 mm (range, 4.0-7.5 mm). When 20 N of tension was
Lateral Meniscal Root Tears Associated With Anterior Cruciate Ligament Injury: Classification and Management (SS-70) Objective: The purpose of this study was to define the incidence of posterior horn lateral meniscal root tears, classify the tear patterns, correlate these findings with the preoperative MRIs, and describe a technique for repair. Methods: The operative notes from 298 consecutive ACL reconstructions (1999-2001) were reviewed to identify associated posterior lateral meniscal root tears. These tears were defined as ones that occurred within one centimeter from the posterior bony insertion of the lateral meniscus. This tear pattern was identified in 37 (12.4%) patients. Two surgeons and one musculoskeletal radiologist performed an independent review of the MRIs, operative records, and arthroscopic pictures. Associated injuries and tear patterns were identified. An arthroscopic classification system and a technique for repair was developed. Results: Preoperative MRIs were available for review in 30 of the 37 patients. MRI findings included abnormal gray signal at the root insertion on the T1 images in 26 (87%) patients. T2 signal changes at the root were much less frequent, occurring in only
ABSTRACTS 57% of patients. Lateral and medial compartment edema was present in 83% and 74% of the patients, respectively. MCL injury was present in 48% of the patients, and partial PCL injury was seen in 30%. Medial meniscal tears and additional lateral meniscal tears were identified in 43% and 22% of the patients, correspondingly. An arthroscopic classification system was developed based on three typical tear patterns. Type I injuries were root avulsions. Type II tears were isolated radial split tears within one centimeter from the root insertion, and type III injuries were complex root tears with radial and longitudinal components. The type I and III tears were amenable to arthroscopic repair using a trans-osseous tunnel technique. Conclusions: The association of lateral meniscal tears with ACL injuries is well documented. However, limited data is available on posterior lateral root tears. The mechanism, incidence, natural history, and associated injuries of lateral root tears is unknown. By disrupting the hoop forces, root tears can potentially have a detrimental effect on the lateral compartment biomechanics. This study has helped to define the incidence of concomitant ACL and lateral root tears, associated injuries, and treatment options. Robin Vereeke West, M.D., Jin Goo Kim, M.D., Derek Armfield, M.D., Christopher D. Harner, M.D. Soft Tissue Injury of the Knee Following Tibial Plateau Fractures (SS-71) Purpose: We contend that significant ligament and meniscal injuries of the knee may occur in association with fractures of the tibial plateau following high-energy mechanism. The purpose of this paper is to document such injury. Methods: Our study was a retrospective analysis of prospectively obtained data on patients sustaining tibial plateau fractures. One hundred and three patients with fractures due to high-energy mechanisms were evaluated with knee MRI. All studies were read by a single musculoskeletal radiologist who was blinded to surgical and physical exam findings. Fractures were classified by both the Schatzker and the OTA systems. Pertinent demographic information was obtained. Results: 33 females and 70 males were evaluated, with 49 right and 54 left tibial plateau fractures. 41C fractures were found in 66 patients, 41B fractures in 37. 73 patients (71%) tore at least one major ligament group (ACL, PCL, posterolateral corner, or posteromedial corner), while 55 tore multiple ligaments. 53 torn ligaments were in 41C fractures (80%), compared to 20 in 41B fractures (54%). This difference was statistically significant (p ⬍ .001 Fisher’s exact). Using Schatzker’s classification, we
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found the following correlation: Type I – 13 fractures with 6 ligaments (46%); Type II – 11 fractures with 5 ligaments (45%); Type III – 0 fractures; Type IV – 13 fractures with 9 ligaments (69%); Type V – 13 fractures with 11 ligaments (85%); and Type VI – 53 fractures with 42 ligaments (79%). A significant difference exists between groups regarding the incidence of ligament injuries (P ⬍ .05 Fisher’s exact). A statistically significant difference (P ⬍ .01 Fisher’s exact) was also found when analyzing ligament injuries in high-energy (IV, V, VI) versus lowenergy (I, II, III) patterns. 27 of our patients (26%) sustained knee dislocations. The incidence of knee dislocation was 32% for 41B fractures and 23% for 41C fractures. Knee dislocations were most common in Schatzker IV fractures (46%). 50 patients sustained meniscus tears (49%), with 25 medial menisci and 35 lateral menisci injuries. 10 patients tore both menisci, 8 were Schatzker VI fractures. 49% of the 41B fractures had meniscal tears, compared with 48% of the 41C fractures. Discussion/Significance: Tibial plateau fractures represent common ground between sports medicine and trauma. In addition, plateau fractures significantly complicate diagnosis of soft tissue injuries of the knee. In the absence of MRI scanning, these injuries are frequently overlooked and may ultimately be a significant source of pain and dysfunction. Recent studies have documented that high-energy tibial plateau fractures do not invariably develop severe arthritis, yet pain and limited motion remain major problems. The incidence of ligament and meniscal injuries is high, regardless of classification. High-energy patterns (41C or Schatzker IV, V, VI) clearly have a significantly higher incidence of ligament injury, and these patients should be carefully evaluated to rule out a spontaneously reduced dislocation. We believe MRI scanning should be performed on all tibial plateau fractures due to high-energy mechanism, allowing identification and treatment of these soft tissue injuries in an effort to improve functional outcome. James P. Stannard, M.D., Stephen L. Brown, M.D., Robert R. Lopez-Ben, M.D., James T. Robinson, undergraduate, Gerald McGwin, Jr., Ph.D., David A. Volgas, M.D. Gains of Visco Supplementation Following Arthroscopic Assisted Surgery of Gonarthrosis of FemoroTibial Joint (SS-72) Osteoarthritis is combination of both mechanical and biochemical derangements. Biochemically, there is reduction in concentration and size of hyaluronic acid in synovial fluid resulting in its decreased viscosity and elasticity and thus cartilage wear. The chondral flaps and debris thus produced cause mechanical derangement by repeatedly
ABSTRACTS
attempted ten consecutive tunnel placements. The deviation in the ten attempts was recorded, as was the difference between the eight investigators. The results showed that the anatomical insertion site on the tibia and femur was accurately arrived at in each case with only minimal deviations. In addition, 300 postoperative x-rays of navigated anterior cruciate ligament replacements were analyzed and the position of the tunnels evaluated. To provide a comparison, 300 non-navigated anterior cruciate ligament replacements were also assessed. Whereas in each of the navigated cases, with only two exceptions, it was possible to achieve the optimal tibial insertion site sagittally at 47% (⫾5%) as well as the dorsal margin of the femoral cortex in the 10 or 2 o’clock position ⫾30 minutes, the tendency could be demonstrated in the non-navigated cruciate ligaments to site the tibial tunnel too far in a dorsal direction (mean value 50%, ⫾3%) and to site the femoral tunnel too high at 11 or 1 o’clock ⫾30 minutes. Through the use of the navigator, it was possible to change over to the anteromedial portal technique when the anatomical area on the femoral insertion was not attained. This occurred distinctly less often with the non-navigated cruciate ligaments.
applied to the graft during ACL reconstruction, the mean AP translation was 3.0 ⫾ 1.1 mm (range, 1.5-4.5 mm). Mean AP translation was 2.3 ⫾ 1.0 mm (range, 1.0-4.0 mm) when 40 N of tension was applied and 1.6 ⫾ 1.0 mm (range, 0.5-3.0 mm) with 80 N of tension. Mean AP translation in the ACL deficient knees was significantly greater than in the intact knees (P ⬍ .00009) and in all 3 reconstruction conditions (P ⬍ .0001 when 20 N and 40 N of tension was applied and P ⬍ .0003 when 80 N was applied). Mean translation when 20 N of tension was applied was significantly greater than when 80 N of tension was applied (P ⬍ .02), but the difference between the 20-N and 40-N conditions did not reach statistical significance (P ⬎ .07). The difference between the 40-N and 80-N conditions was significant (P ⬍ .02). None of the reconstruction conditions were found to be significantly different from the intact knees (P ⬎ .40 at 20 N, P ⬎ .65 at 40 N, and P ⬎ .23 at 80 N). Conclusions: In a cadaver model, tensioning a soft tissue ACL graft to 80 N provides greater AP knee stability immediately after reconstruction than 40 N or 20 N of graft tension. Further clinical studies are needed to determine the effects of graft tensioning on long-term knee stability and patient outcomes.
Ju¨ rgen Eichhorn, M.D.
Jeffrey C. Easom, D.O., Vipool K. Goradia, M.D., Sara E. Pearson, Ph.D., William B. Wiley, M.D.
Anterior Cruciate Ligament Tensioning: KT-1000 Measurements After Anterior Cruciate Ligament Reconstruction and Tensioning (SS-68) Purpose: With the increased availability of different tensioning devices, much attention has been focused on the amount of tension that is placed on anterior cruciate ligament (ACL) grafts during ACL reconstruction. The goal of this study was to analyze the effect of applying different levels of tension during ACL reconstruction on anterior-posterior (AP) translation in cadaveric knees. Type of Study: Cadaveric analysis. Methods: The posterior tibial tendon was harvested in 7 cadaveric specimens and used in ACL reconstruction. AP translation was measured with a KT-1000 in the intact knees, after ACL resection, and after ACL reconstruction with the graft tensioned at 20 N, 40 N, and 80 N. Graft tension was applied and measured using the Linvatec Stress Equalization (SE) Graft Tensioning System (Largo, FL). A maximum manual KT-1000 anterior force was applied by a single examiner with each knee at 30° of knee flexion. Results: The average AP translation in the intact knees was 2.6 ⫾ 1.1 mm (range, 1.0-4.0 mm). The average AP translation after ACL resection was 6.2 ⫾ 1.3 mm (range, 4.0-7.5 mm). When 20 N of tension was
Lateral Meniscal Root Tears Associated With Anterior Cruciate Ligament Injury: Classification and Management (SS-70) Objective: The purpose of this study was to define the incidence of posterior horn lateral meniscal root tears, classify the tear patterns, correlate these findings with the preoperative MRIs, and describe a technique for repair. Methods: The operative notes from 298 consecutive ACL reconstructions (1999-2001) were reviewed to identify associated posterior lateral meniscal root tears. These tears were defined as ones that occurred within one centimeter from the posterior bony insertion of the lateral meniscus. This tear pattern was identified in 37 (12.4%) patients. Two surgeons and one musculoskeletal radiologist performed an independent review of the MRIs, operative records, and arthroscopic pictures. Associated injuries and tear patterns were identified. An arthroscopic classification system and a technique for repair was developed. Results: Preoperative MRIs were available for review in 30 of the 37 patients. MRI findings included abnormal gray signal at the root insertion on the T1 images in 26 (87%) patients. T2 signal changes at the root were much less frequent, occurring in only
ABSTRACTS 57% of patients. Lateral and medial compartment edema was present in 83% and 74% of the patients, respectively. MCL injury was present in 48% of the patients, and partial PCL injury was seen in 30%. Medial meniscal tears and additional lateral meniscal tears were identified in 43% and 22% of the patients, correspondingly. An arthroscopic classification system was developed based on three typical tear patterns. Type I injuries were root avulsions. Type II tears were isolated radial split tears within one centimeter from the root insertion, and type III injuries were complex root tears with radial and longitudinal components. The type I and III tears were amenable to arthroscopic repair using a trans-osseous tunnel technique. Conclusions: The association of lateral meniscal tears with ACL injuries is well documented. However, limited data is available on posterior lateral root tears. The mechanism, incidence, natural history, and associated injuries of lateral root tears is unknown. By disrupting the hoop forces, root tears can potentially have a detrimental effect on the lateral compartment biomechanics. This study has helped to define the incidence of concomitant ACL and lateral root tears, associated injuries, and treatment options. Robin Vereeke West, M.D., Jin Goo Kim, M.D., Derek Armfield, M.D., Christopher D. Harner, M.D. Soft Tissue Injury of the Knee Following Tibial Plateau Fractures (SS-71) Purpose: We contend that significant ligament and meniscal injuries of the knee may occur in association with fractures of the tibial plateau following high-energy mechanism. The purpose of this paper is to document such injury. Methods: Our study was a retrospective analysis of prospectively obtained data on patients sustaining tibial plateau fractures. One hundred and three patients with fractures due to high-energy mechanisms were evaluated with knee MRI. All studies were read by a single musculoskeletal radiologist who was blinded to surgical and physical exam findings. Fractures were classified by both the Schatzker and the OTA systems. Pertinent demographic information was obtained. Results: 33 females and 70 males were evaluated, with 49 right and 54 left tibial plateau fractures. 41C fractures were found in 66 patients, 41B fractures in 37. 73 patients (71%) tore at least one major ligament group (ACL, PCL, posterolateral corner, or posteromedial corner), while 55 tore multiple ligaments. 53 torn ligaments were in 41C fractures (80%), compared to 20 in 41B fractures (54%). This difference was statistically significant (p ⬍ .001 Fisher’s exact). Using Schatzker’s classification, we
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found the following correlation: Type I – 13 fractures with 6 ligaments (46%); Type II – 11 fractures with 5 ligaments (45%); Type III – 0 fractures; Type IV – 13 fractures with 9 ligaments (69%); Type V – 13 fractures with 11 ligaments (85%); and Type VI – 53 fractures with 42 ligaments (79%). A significant difference exists between groups regarding the incidence of ligament injuries (P ⬍ .05 Fisher’s exact). A statistically significant difference (P ⬍ .01 Fisher’s exact) was also found when analyzing ligament injuries in high-energy (IV, V, VI) versus lowenergy (I, II, III) patterns. 27 of our patients (26%) sustained knee dislocations. The incidence of knee dislocation was 32% for 41B fractures and 23% for 41C fractures. Knee dislocations were most common in Schatzker IV fractures (46%). 50 patients sustained meniscus tears (49%), with 25 medial menisci and 35 lateral menisci injuries. 10 patients tore both menisci, 8 were Schatzker VI fractures. 49% of the 41B fractures had meniscal tears, compared with 48% of the 41C fractures. Discussion/Significance: Tibial plateau fractures represent common ground between sports medicine and trauma. In addition, plateau fractures significantly complicate diagnosis of soft tissue injuries of the knee. In the absence of MRI scanning, these injuries are frequently overlooked and may ultimately be a significant source of pain and dysfunction. Recent studies have documented that high-energy tibial plateau fractures do not invariably develop severe arthritis, yet pain and limited motion remain major problems. The incidence of ligament and meniscal injuries is high, regardless of classification. High-energy patterns (41C or Schatzker IV, V, VI) clearly have a significantly higher incidence of ligament injury, and these patients should be carefully evaluated to rule out a spontaneously reduced dislocation. We believe MRI scanning should be performed on all tibial plateau fractures due to high-energy mechanism, allowing identification and treatment of these soft tissue injuries in an effort to improve functional outcome. James P. Stannard, M.D., Stephen L. Brown, M.D., Robert R. Lopez-Ben, M.D., James T. Robinson, undergraduate, Gerald McGwin, Jr., Ph.D., David A. Volgas, M.D. Gains of Visco Supplementation Following Arthroscopic Assisted Surgery of Gonarthrosis of FemoroTibial Joint (SS-72) Osteoarthritis is combination of both mechanical and biochemical derangements. Biochemically, there is reduction in concentration and size of hyaluronic acid in synovial fluid resulting in its decreased viscosity and elasticity and thus cartilage wear. The chondral flaps and debris thus produced cause mechanical derangement by repeatedly