Prevalence of Segond fractures associated with anterior cruciate ligament injuries and their influence on knee joint stability; A case-control study.

BACKGROUND: The purpose of this study was to determine the prevalence of Segond fractures and to compare knee stability between patients undergoing primary anterior cruciate ligament (ACL) reconstruction with and without Segond fractures pre- and postoperatively. METHODS: A total of 712 patients who underwent primary ACL reconstruction between 2014 and 2019. Exclusion criteria included patients with multi-ligament knee injuries, skeletally immature patients, osteoarthritis in the knee, combined surgery of high tibial osteotomy, lack of data, and loss to follow-up for at least 2 years. Segond fractures were confirmed using plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Patients with Segond fractures were classified into Group S and without Segond fractures into Group N. Pre- and postoperative Lachman grades, pivot-shift grades, and assessment of side-to-side differences in anterior stability were evaluated. RESULTS: Five hundred and forty patients included in this study. There were 22 patients with Segond fractures. Of these, all 22 cases (4.1%) were identified on CT, but only 20 cases (3.7%) were identified on MRI and 18 cases (3.3%) on plain radiographs. There was no significant difference in preoperative Lachman grade or pivot-shift grade between Groups S and N (p = 0.662, p = 0.677, respectively). There was no significant difference in postoperative Lachman grade or pivot-shift grade between Groups S and N (p = 0.685, p = 0.390, respectively). There were no significant differences in preoperative (p = 0.398) or postoperative (p = 0.546) side-to-side differences of anterior stability between Groups S and N. CONCLUSIONS: Segond fractures were confirmed in 4.1% of the cases on CT scans among patients undergoing primary ACL reconstruction. Segond fractures did not affect preoperative or 2-year follow-up evaluations of knee stability. From these results, we concluded that Segond fractures did not affect the clinical outcomes of the primary ACL reconstruction and that it may not be necessary to treat Segond fractures.

Biomechanical analysis of bioabsorbable suture anchors for rotator cuff repair using osteoporotic and normal bone models.

BACKGROUND: This study aimed to compare the failure load of suture anchors used in rotator cuff repair between normal and osteoporotic bone models. METHODS: A total of 16 anchors made from metal (TwinFix Ti 5.0 or 6.5 mm, Corkscrew FT 4.5, 5.5, or 6.5 mm), polyether ether ketone (HEALICOIL PK [HC-PK] 4.5 or 5.5 mm, SwiveLock PK 4.75 or 5.5 mm), or bioabsorbable material (HEALICOIL RG [HC-RG] 4.75 or 5.5 mm, Corkscrew Bio 4.75, 5.5, or 6.5 mm, SwiveLock BC 4.75 or 5.5 mm) were included. Moreover, 10- and 5-pounds per cubic foot (pcf) Sawbone® models were set as normal and osteoporotic cancellous bone models, respectively. Pullout testing was performed in parallel to the insertion axis at a displacement rate of 12.5 mm/s using a universal testing machine. To evaluate the change in failure load between the two Sawbone® models with different densities, the remaining failure load ratio (RFLR) was defined as the ratio of the failure load in 10 pcf to that in 5 pcf. RESULTS: In the 10-pcf Sawbone®, TwinFix Ti 6.5 mm showed the highest mean failure load (304.0 ± 15.2 N). In the 5-pcf Sawbone® model, HC-PK 5.5 mm showed the highest failure load (146.3 ± 5.8 N). Among anchors with the same diameter, HC-PK and HC-RG showed a significantly higher failure load than other anchors in the 10- and 5-pcf Sawbone® models. HC-PK 5.5 mm (62.1%) and HC-PK 4.5 mm (51.1%) have the highest RFLR among anchors with the same diameter. CONCLUSIONS: HC-PK and HC-RG showed higher failure load than the other anchors in both normal and osteoporotic bone models, except for TwinFix Ti 6.5 mm in the 10-pcf Sawbone® model. Based on our results, bioabsorbable anchors had sufficient failure load for rotator cuff repair in addition to bioabsorbability.

Effect of medial collateral ligament release and osteophyte resection on medial laxity in total knee arthroplasty.

PURPOSE: The concept of medial stabilizing technique total knee arthroplasty (MST-TKA) is to minimize the medial release without the superficial layer of medial collateral ligament (MCL). However, it is unclear at what stage the proper medial laxity is obtained during surgery. The purpose of this study was to investigate the implication of deep layer of MCL (dMCL) and osteophyte resection on medial laxity during MST-TKA. METHODS: A total of 103 consecutive patients who underwent cruciate-retaining TKA using the navigation system were included. The intraoperative hip-knee-ankle (HKA) angle was recorded under three conditions (no stress, valgus, and varus stress) at four time points after the resection of the anterior cruciate ligament (ACL) and meniscus (1st evaluation), after the dMCL release (2nd evaluation), and after osteophyte resection on both the femoral and tibial side (3rd evaluation). To assess valgus laxity, the differences in intraoperative HKA angle between 1st and 2nd evaluation (stage 1) and between 2nd and 3rd evaluation (stage 2) were calculated. RESULTS: Under the valgus stress condition, the intraoperative HKA angle change in stage 2 was significantly larger than that in stage 1 in full extension (stage 1; - 0.5 ± 1.0°, stage 2; - 2.0 ± 1.3°, p < 0.001) and 30° flexion (stage 1; - 0.8 ± 1.4°, stage 2; - 1.5 ± 2.0°, p = 0.008). There were no significant differences at 60° and 90° of knee flexion. Under the no stress and varus stress conditions, there were no significant differences in knee flexion at all angles. CONCLUSION: The medial laxity during MST-TKA increased significantly more after dMCL release and osteophyte resection than after just dMCL release at full extension and 30° flexion, and it was, therefore, considered that osteophyte resection is a key procedure for a successful MST-TKA. LEVEL OF EVIDENCE: Level II, therapeutic prospective cohort study.

Effects of the tibial tunnel position on knee joint stability and meniscal contact pressure after double-bundle anterior cruciate ligament reconstruction.

BACKGROUND: To investigate the effect of the tibial tunnel position on knee stability and the maximum contact area and peak contact pressure on the menisci after double-bundle anterior cruciate ligament (ACL) reconstruction. METHODS: Ten human knee specimens (mean age: 74.1 ± 15.8 years) were used in this study. The anterior tibial loading test was conducted using a material testing machine at 30°, 60°, and 90° of knee flexion, with the anterior tibial translation (ATT) and the maximum contact area and peak contact pressure on the menisci measured. Outcome measures were compared between the following groups: 1) intact ACL (intact group); 2) anatomical tibial tunnel position (anatomical group) and 3) posterior tibial tunnel position (posterior group) with double-bundle reconstruction, and 4) ACL-deficient (deficient group). RESULTS: In response to a 100 N anterior tibial load, the ATT was greater for the posterior and ACL-deficient groups compared to that in the intact group. The normalized maximum contact area of the medial meniscus significantly decreased for the posterior group compared to that in the intact group. The normalized peak contact pressure on the medial meniscus increased in all groups compared to that in the intact group, but with no between-group differences in pressure applied to the lateral meniscus. CONCLUSIONS: ATT and contact pressure on the medial meniscus increased, concomitant with a decrease in contact area of the medial meniscus, as the position of the tibial tunnel position moved towards a posterior position.

Biomechanical analysis of medial patellofemoral ligament reconstruction: FiberTape® with knotless anchors versus a semitendinosus tendon autograft with soft anchors.

BACKGROUND: With the use of synthetic materials for medial patellofemoral ligament (MPFL) reconstruction, graft harvest is not necessary and this may facilitate post-operative rehabilitation. The purpose of this study was to compare the structural properties of MPFL reconstruction using a modern synthetic material (FiberTape® (FT), Arthrex) with knotless anchors or a semitendinosus (ST) tendon autograft with soft anchors. METHODS: Nine human fresh-frozen amputated knees were used in this study. After the tensile strength of the native MPFL was measured, the MPFLs were reconstructed using two different surgical procedures, FT with knotless anchors (group A) and a ST with soft anchors (group B). Mechanical testing to failure of the reconstructed MPFLs was performed, and the ultimate load (N), stiffness (N/mm), and failure mode were recorded. RESULTS: The mean (±standard deviation) ultimate load of the native MPFL was 130.6 ± 28.7 N, and all native MPFLs failed at the femoral insertion site. Ultimate load of group A was significantly higher than that of the native MPFL (175.9 ± 34.1 N, p < 0.05). In contrast, the ultimate load of group B was significantly lower than that of the native MPFL (102.7 ± 21.4 N, p < 0.05). The mean stiffness was significantly higher for MPFLs in group A (17.4 ± 4.3 N/mm) than in group B (8.5 ± 1.8 N/mm, p < 0.05). In group A, 5 specimens failed via a knotless anchor pullout at the femoral side, 3 via pullout of knotless anchors at the patella side and 1 via fracture (cheese cut) of the femur without breakage of knotless anchor. In group B, all specimens failed via soft anchor pullout at the patella side. There was no incidence of rupture of FT or ST. CONCLUSION: FT with knotless anchors was stronger than a ST with soft tissue anchors for MPFL reconstruction.

Tunnel malpositions in anterior cruciate ligament risk cartilaginous changes and bucket-handle meniscal tear: Arthroscopic survey in both primary and revision surgery.

OBJECTIVES: There are not many chances to arthroscopically reassess how graft tunnel malpositions in primary anterior cruciate ligament reconstruction (ACLR) associate with intra-articular degeneration in revision ACLR. This study was aimed to evaluate whether radiographic tunnel position in primary ACLR affect cartilaginous changes and bucket-handle meniscus tears in revision ACLR. METHODS: Thirty-five patients who underwent revision ACLR were recruited; their primary surgeries were single-bundle reconstructions. Tunnel positions were evaluated using the plain radiographs after primary surgery. The sagittal tunnel positions of the femur (FP) and tibia (TP) were determined on the lateral view. The articular cartilage was evaluated arthroscopically at primary and revision surgery using the International Cartilage Repair Society (ICRS) score. A progression of two grades was considered as cartilaginous changes. Meniscal tears were evaluated with an arthroscopic probe. Logistic regression analysis was conducted using the prevalence of cartilaginous changes or bucket-handle meniscus tears as the dependent variable; tunnel parameters were used as the independent variables. RESULTS: Seven patients (20.0%) had cartilaginous changes and nine patients (25.7%) had bucket-handle tears in the medial meniscus. In logistic regression analysis, %FP [odds ratio (OR): 1.212; P = 0.007] and the cut-off of 60% in the FP (OR: 22.000; P = 0.008) were correlated with cartilaginous changes. %TP (OR: 1.126; P = 0.036) was correlated with the prevalence of bucket-handle meniscus tears. CONCLUSIONS: Anterior femoral tunnel malposition in the femur was associated with the cartilaginous changes, and posterior tibial tunnel malposition with the development of bucket-handle meniscus tears.

Biomechanical evaluation of an anatomic double-bundle posterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the effect of the anatomic double-bundle reconstruction (ADBR) of the posterior cruciate ligament (PCL) with 2 femoral tunnels and 2 tibial tunnels. METHODS: Eight fresh-frozen human knees were used. Bone tunnels were created based on the PCL anatomic footprints. A 9-mm looped semitendinosus and gracilis tendon for anterolateral bundle reconstruction (ALR), a 7-mm looped semitendinosus tendon for posteromedial bundle reconstruction (PMR), and the same grafts for the ADBR were used. Under a 100-N posterior tibial load and under a 100-N posterior tibial load and 5 Nm of external tibial torque, the posterior tibial translation (PTT) was measured. RESULTS: Under posterior tibial load, at 0°, the PTT of the ALR was larger than that of the intact knee (P = .04) and the ADBR (P = .03); however, there were no significant differences between the PTT of the PMR and that of the ADBR (P = .28) and intact knee (P = .99). At 30°, the PTT of the ADBR was smaller than that of the ALR (P = .02) and PMR (P = .02). At 60°, the PTT of the PMR was larger than that of the ADBR (P = .02). At 90°, the PTT of the PMR was larger than that of the ADBR (P = .02). Under posterior tibial load and external tibial torque, at 0°, the PTT of the ALR was larger than that of the ADBR (P = .04). CONCLUSIONS: Although the graft size of the ADBR was larger than other reconstructions, the ADBR was better than the ALR at 0° and 30° of knee flexion under the posterior tibial load and at 0° under the combination of posterior tibial load and external tibial torque, as well as better than the PMR at 30°, 60°, and 90° of knee flexion under the posterior tibial load. CLINICAL RELEVANCE: The clinical outcome of PCL reconstruction might improve by reducing posterior knee laxity in knee extension with the ADBR.

Mechanisms for anterior cruciate ligament injuries in badminton.

INTRODUCTION: A high incidence of anterior cruciate ligament (ACL) injuries related to sports activities has been reported; however, the injury situation of ACL injury in badminton has not been elucidated. This study investigated the mechanism of ACL injury in badminton using a questionnaire. METHODS: Information on injury mechanism was gathered from interviews with six male and 15 female badminton players who received a non-contact ACL injury playing badminton and underwent ACL reconstruction. RESULTS: The most common injury mechanism (10 of 21 injuries) was single-leg landing after overhead stroke. Nine of 10 players had injured the knee opposite to the racket-hand side. The second most frequent injury mechanism (eight of 21 injuries) was plant-and-cut while side-stepping or backward stepping. All eight players injured the knee of the racket-hand side. Eleven injuries occurred in the rear court, and six of the 11 injuries occurred during single-leg landing after an overhead stroke. CONCLUSION: The knee opposite to the racket-hand side tended to sustain the ACL injuries during single-leg landing after a backhand overhead stroke, whereas the knee of the racket-hand side tended to be injured by plant-and-cut during side or backward stepping. These injury patterns appear to be due to specific movements during badminton.

Intraoperative comparison of knee laxity between anterior cruciate ligament-reconstructed knee and contralateral stable knee using navigation system.

PURPOSE: The objective of this study was to compare knee laxity between anterior cruciate ligament (ACL)-reconstructed knees and contralateral stable knees by use of intraoperative navigation. METHODS: Five patients with ipsilateral ACL-deficient knees with contralateral stable knees without any ligament injuries were included in this study. Anteroposterior (AP) knee laxity during anterior drawer force applied manually and range of tibial rotation and AP knee laxity during internal and external rotational torque applied manually in both the ACL-deficient knee and the contralateral stable knee were measured by use of a navigation system from 15 degrees to 90 degrees of knee flexion. After the temporary fixation of the posterolateral bundle, anteromedial bundle (AMB), or double-bundle (DB) reconstruction, knee laxity was measured again and compared with that of the stable knee. RESULTS: The mean laxities for PLB reconstruction were significantly greater than those of the contralateral stable knee at more than 75 degrees of knee flexion (P < .05). The mean laxities for AMB or DB reconstruction were not significantly different from those of the contralateral stable knee at all knee flexion angles. Those for AMB reconstruction were within +1.6 mm and those for DB reconstruction were within -2.0 mm of those of the contralateral stable knee. The mean rotations for all reconstructions were significantly less than those of the contralateral stable knee at less than 30 degrees of knee flexion (P < .05). CONCLUSIONS: DB and AMB reconstructions could restore knee laxity closer to the level of the contralateral stable knee. Because normal knee laxity is different in each individual, evaluation of contralateral stable knee laxity during ACL reconstruction surgery would be helpful for restoration to the level of the specific preinjury knee laxity. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The actual tendon-bone interface strength in a rabbit model.

PURPOSE: The purpose of this study was to evaluate the strength of the interface throughout the entire integration process by use of tendon graft reinforced with a suture material compared with nonreinforced tendon graft. METHODS: Using 60 skeletally mature female Japanese white rabbits, we performed biomechanical testing and histologic evaluation to compare tendon grafts reinforced with a suture material (suture group) and nonreinforced grafts (control group). The tendon graft was drawn through a bone tunnel measuring 2.5 mm in diameter and was tightly fixed. For biomechanical testing, the tendon graft was tested in tensile loading along the axis of the bone tunnel at a crosshead speed of 100 mm/min. RESULTS: On biomechanical testing, at 4, 6, 8, and 12 weeks, tendon grafts had pulled out of the bone tunnel in the suture group. In the control group all tendon grafts had pulled out at 4 and 6 weeks, and rupture at the midsubstance was seen at 8 and 12 weeks. The failure load-to-tunnel length ratio was significantly larger in the suture group compared with the control group at 8 and 12 weeks. On histologic evaluation, both groups had similar findings with direct attachments to bone by 12 weeks. CONCLUSIONS: In this study of the healing characteristics of augmented and nonaugmented tendon grafts placed in a bone tunnel, we found that the suture-augmented tendons had superior failure load-to-tunnel length ratios at 8, 12, and 16 weeks compared with nonaugmented tendons. The failure mode in the augmented grafts was tendon pullout at all time points except 16 weeks, whereas the nonaugmented grafts failed by midsubstance rupture after 8 weeks. Histologically, both groups had similar findings with direct attachments to bone by 12 weeks. CLINICAL RELEVANCE: The tendon graft has the potential to be pulled out of the bone tunnel after complete integration.

Comparable results between lateralized single- and double-bundle ACL reconstructions.

UNLABELLED: Patellar tendon autografts are not suitable for multibundle ACL reconstruction, a procedure that reportedly enhances postoperative knee stability. Biomechanical studies recommend lateral placement of the femoral tunnel for single-bundle reconstruction to improve postoperative knee kinematics. We asked whether a lateralized single-bundle patellar tendon graft (LSBP) would provide good short-term results of ACL reconstruction comparable to double-bundle hamstring tendon grafts (DBH). We prospectively followed 144 patients with unilateral ACL rupture treated with either LSBP or DBH in a nonrandomized fashion. Twenty-four female and 31 male patients with LSBP and 44 female and 26 male patients with DBH were followed for a minimum of 24 months (average, 38 months; range, 24-56 months). The patients with LSBP recovered knee extension better at 1 month compared with the patients with DBH, but extension was similar after 3 months. We observed no differences in the side-to-side difference of KT1000 measurement, pivot shift test, or anterior drawer test between LSBP and DBH. Although better recovery of hamstring strength in LSBP and better recovery of quadriceps strength in DBH were observed in the early postoperative period, these differences disappeared after 12 months. There was no difference in International Knee Documentation Committee objective evaluation between LSBP and DBH at the final followup. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Navigation evaluation of the pivot-shift phenomenon during double-bundle anterior cruciate ligament reconstruction: is the posterolateral bundle more important?

PURPOSE: The purpose of this study was to assess the pivot-shift phenomenon during double-bundle anterior cruciate ligament (ACL) reconstruction using a navigation system. METHODS: Ninety patients who received navigated double-bundle ACL reconstruction were included in this study. The mean age of the patients was 21.9 years. During reconstruction, pivot-shift tests were performed 4 times: before reconstruction, after the posterolateral bundle fixation, after the anteromedial bundle fixation, and after the double-bundle reconstruction. Both tibial internal rotation and anterior translation under the pivot-shift test were measured at each phase by the additional functions of the navigation. The navigation system used in this study was the image-free, which does not require preoperative or intraoperative images, OrthoPilot ACL (version 2.0; B. Braun Aesculap, Tuttlingen, Germany). RESULTS: Before ACL reconstruction, average (+/- standard deviation) tibial internal rotation and anterior translation under the pivot-shift test were 23.7 degrees +/- 6.1 degrees and 5.2 +/- 2.4 mm. They were significantly decreased to 20.9 degrees +/- 6.4 degrees and 2.3 +/- 1.1 mm after the posterolateral bundle fixation, and also decreased to 22.2 degrees +/- 5.7 degrees and 2.4 +/- 1.1 mm after the anteromedial bundle fixation. There was no significant difference between the groups. After double-bundle reconstruction, they improved to 20.3 degrees +/- 6.3 degrees and 2.0 +/- 1.0 mm. CONCLUSIONS: Our results indicate that both the posterolateral and the anteromedial bundle similarly control both anterior translation and internal rotation during pivot-shift testing. Double-bundle reconstruction may further improve knee stability. LEVEL OF EVIDENCE: Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.

Validation of computer-assisted double-bundle anterior cruciate ligament reconstruction.

The goal of this study was to establish the reliability of a navigation system for femoral tunnel placement in arthroscopic double-bundle anterior cruciate ligament (ACL) reconstruction. Guidewires were inserted to the center of the anteromedial and posterolateral femoral tunnels of eight porcine knees using an image-free navigation system. The relative position of the guidewires in reference to the height and depth of the lateral condyle was determined by the navigation system and a digital camera and compared. The average differences in high-low and deep-shallow position between the two measurement systems were 2.6% +/- 1.3% (range, 0.6%-4.9%) and 1.6% +/- 1.4% (range, 0.1%-4.0%) for the anteromedial tunnels and 2.7% +/- 1.4% (range, 0%-3.9%) and 2.6% +/- 1.3% (range, 1.1%-4.3%) for the posterolateral tunnels. The data suggest that the navigation system provided surgeons with reliable information to determine the femoral tunnel location in arthroscopic double-bundle ACL reconstruction.

Characteristics of elongated and ruptured anterior cruciate ligament grafts: An analysis of 21 consecutive revision cases.

BACKGROUND/OBJECTIVE: Anterior cruciate ligament (ACL) reconstructions often fail without graft rupture. The purpose of this study was to compare the characteristics of patients with elongated and ruptured bone-patellar tendon-bone (BTB) grafts that required revision surgery. METHODS: Twenty one patients who required revisions of a BTB-reconstructed ACL between 2010 and 2015 were enrolled in this study. All patients were evaluated for bone tunnel position using computed tomography. Tunnel angle was calculated with radiographs. Stability under anaesthesia, and meniscus and cartilage condition were evaluated during the revision surgery. Age at primary surgery, time between primary and revision surgery, activity level, original tunnel position of the graft, and meniscus and cartilage condition were compared between elongated and ruptured grafts. RESULTS: Age at primary surgery was not significantly different between the two groups (p = 0.528). Time between primary and revision surgery as well as activity level were also not significantly different between the two groups (p = 0.010 and p = 0.307, respectively). Femoral bone tunnel position was more proximal (p = 0.003), and radiographic tunnel angle was not significantly different between the two groups (p = 0.029). The rupture group was significantly more unstable on the pivot shift (p < 0.003). Meniscus degeneration, meniscus tear, and cartilage damage were not significantly different between the two groups (p = 0.030, p = 0.311, and p = 0.505, respectively). CONCLUSION: The location of the original femoral tunnel was more proximal in patients with elongated grafts than in those with ruptured grafts. Different bone tunnel position from native ACL might lead to graft elongation.

Future of double-bundle anterior cruciate ligament (ACL) reconstruction: incorporation of ACL anatomic data into the navigation system.

This study compares anatomy and tunnel placement during double-bundle procedures. Double-bundle anterior cruciate ligament (ACL) reconstruction reproduces both the anteromedial and posterolateral bundles. Thirty-six knees from cadavers were used for anatomic study, and 38 navigated double-bundle ACL reconstructions were evaluated for tunnel placements. With the exception of femoral tunnels of anteromedial bundles, all tunnel placements were in accordance with the anatomic measurements of the native ACL. The investigators concluded that incorporating ACL anatomic information into navigation systems would enhance double-bundle procedures.

A biomechanical comparison of repair techniques for anterior cruciate ligament tibial avulsion fracture under cyclic loading.

PURPOSE: Although several technical developments for arthroscopic treatment of anterior cruciate ligament (ACL) avulsion fracture have been reported, it remains unclear which fixation technique is most effective to obtain the best initial fixation strength. The objectives of this study were to compare the initial fixation strength in response to a cyclic tensile load between different fixation techniques for ACL avulsion fractures. TYPE OF STUDY: Cadaveric biomechanical evaluation. METHODS: Using 15 fresh-frozen cadaveric human knees, 3 different fixation techniques for noncomminuted ACL avulsion fractures were compared by measuring the anterior tibial translation (ATT) under 500 cycles of 0 to 100 N of anterior tibial load: (1) antegrade screw fixation, (2) retrograde screw fixation, and (3) pullout suture fixation. RESULTS: The increase in the ATT after the cyclic loading for the pullout suture fixation (2.2 +/- 0.8 mm) was significantly larger than that for the antegrade screw fixation (1.0 +/- 0.2 mm). The ATT increase in the retrograde fixation group (2.0 +/- 0.6 mm) was not significantly different compared with the other groups. CONCLUSIONS: All methods were effective and there was a slight biomechanical advantage to antegrade screw fixation over pullout suture fixation. CLINICAL RELEVANCE: Antegrade screw fixation is more effective in obtaining initial rigid fixation than pullout suture fixation for ACL avulsion fractures.

Biomechanical comparison between single-bundle and double-bundle anterior cruciate ligament reconstruction with hamstring tendon under cyclic loading condition.

PURPOSE: The purpose of this study was to compare the anterior tibial translation (ATT) of the anterior cruciate ligament (ACL) reconstructed-knee between single-bundle and double-bundle ACL reconstruction under cyclic loading. METHODS: Single-bundle and double-bundle reconstructions of the knee were performed sequentially in randomized order on the same side using eight human amputated knees. After each reconstruction, the reconstructed-knee was subjected to 500-cycles of 0 to 100-N anterior tibial loads using a material testing machine. The ATT before and after cyclic loading and "laxity increase", which indicated a permanent elongation of the graft construct, was also determined. RESULTS: The ATT after cyclic loading increased in both single-bundle and double-bundle reconstruction techniques compared to that without cyclic loading. Changes in ATT before and after cyclic loading were 3.9 ± 0.9 mm and 2.9 ± 0.6 mm respectively, and were significantly different. Laxity increase was also significantly different (4.3 ± 0.9 mm and 3.2 ± 0.8 mm respectively). Although no graft rupture or graft fixation failure was found during cyclic loading, the graft deviated into an eccentric position within the tunnel. CONCLUSIONS: Although ATT was significantly increased in both single-bundle and double-bundle reconstruction with hamstring tendon after cyclic loading test, there was significant difference. Double-bundle reconstruction might be superior to prevent increasing ATT under cyclic loading. Deformation of hamstring tendon after cyclic loading might result in deterioration of knee stability after ACL reconstruction, and is one of disadvantages of soft tissue graft.

Comparison between clinical grading and navigation data of knee laxity in ACL-deficient knees.

BACKGROUND: The latest version of the navigation system for anterior cruciate ligament (ACL) reconstruction has the supplementary ability to assess knee stability before and after ACL reconstruction. In this study, we compared navigation data between clinical grades in ACL-deficient knees and also analyzed correlation between clinical grading and navigation data. METHODS: 150 ACL deficient knees that received primary ACL reconstruction using an image-free navigation system were included. For clinical evaluation, the Lachman, anterior drawer, and pivot shift tests were performed under general anesthesia and were graded by an examiner. For the assessment of knee stability using the navigation system, manual tests were performed again before ACL reconstruction. Navigation data were recorded as anteroposterior (AP) displacement of the tibia for the Lachman and anterior drawer tests, and both AP displacement and tibial rotation for the pivot shift test. RESULTS: Navigation data of each clinical grade were as follows; Lachman test grade 1+: 10.0 mm, grade 2+: 13.2 ± 3.1 mm, grade 3+: 14.5 ± 3.3 mm, anterior drawer test grade 1+: 6.8 ± 1.4 mm, grade 2+: 7.4 ± 1.8 mm, grade 3+: 9.1 ± 2.3 mm, pivot shift test grade 1+: 3.9 ± 1.8 mm/21.5° ± 7.8°, grade 2+: 4.8 ± 2.1 mm/21.8° ± 7.1°, and grade 3+: 6.0 ± 3.2 mm/21.1° ± 7.1°. There were positive correlations between clinical grading and AP displacement in the Lachman, and anterior drawer tests. Although positive correlations between clinical grading and AP displacement in pivot shift test were found, there were no correlations between clinical grading and tibial rotation in pivot shift test. CONCLUSIONS: In response to AP force, the navigation system can provide the surgeon with correct objective data for knee laxity in ACL deficient knees. During the pivot shift test, physicians may grade according to the displacement of the tibia, rather than rotation.

Tunnel position and relationship to postoperative knee laxity after double-bundle anterior cruciate ligament reconstruction with a transtibial technique.

BACKGROUND: Several laboratory studies have pointed out a potential risk of femoral tunnel misplacement in anterior cruciate ligament reconstruction with a transtibial technique. The tunnel malposition away from the anatomic attachment may result in increased postoperative knee laxity in double-bundle reconstruction. PURPOSE: This study was conducted to evaluate the femoral and tibial tunnel positions in transtibial double-bundle reconstruction, and to determine the relationship between the tunnel positions and the results of the postoperative knee laxity examinations. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fifty-three of 71 patients who underwent transtibial double-bundle reconstruction from 2004 to 2005 were followed more than 24 months. The tunnel positions for the anteromedial and posterolateral grafts were measured using 3-dimensional computed tomography images applying the quadrant method. The postoperative knee laxity was examined with the KT-1000 arthrometer manual maximum test, anterior drawer test, and pivot-shift test. RESULTS: The deep-shallow position (parallel to Blumensaat's line) and high-low position (perpendicular to Blumensaat's line) of the femoral tunnels were 27.7% +/- 5.6% from the most posterior condylar contour and 16.3% +/- 5.2% from Blumensaat's line for the anteromedial graft, and 35.5% +/- 6.4% and 48.0% +/- 5.4% for the posterolateral graft. The medial-lateral and anterior-posterior positions of the tibial tunnels were 46.1% +/- 2.6% from the most medial contour and 36.5% +/- 4.9% from the most anterior contour for the anteromedial graft, and 47.5% +/- 3.1% and 51.6% +/- 5.0% for the posterolateral graft. There was no statistical correlation between any parameters of the femoral or tibial tunnel position and the results of the knee laxity tests. CONCLUSION: The femoral tunnels placed in transtibial double-bundle reconstruction were located appropriately in high-low and deep-shallow orientation, but had larger variability than the previously reported data of the anatomic femoral attachment. However, the variability of the femoral tunnel position was not so large as to result in graft insufficiency with increased postoperative knee laxity.