Revision anterior cruciate ligament reconstruction using a 2-stage technique with bone grafting of the tibial tunnel

BACKGROUND: Revision anterior cruciate ligament surgery is often considered a salvage procedure with limited goals. However, this limitation need not be the case. Similar to primary reconstruction, the goal should be to choose an appropriate graft and place it in an anatomical position in a good quality bone. The issue of good quality bone seems to have been ignored. HYPOTHESIS: A 2-stage anterior cruciate ligament revision reconstruction with bone grafting of the tibial tunnel and the use of a different femoral tunnel will produce measured knee laxity and International Knee Documentation Committee scores similar to a primary anterior cruciate ligament reconstruction. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: This prospective study involved 49 consecutive 2-stage anterior cruciate ligament revisions (group R) performed by a single surgeon from 1993 to 2000. Two-stage revision surgery was performed if the tibial tunnel from a previous reconstruction surgery would overlap (either partially or fully) the correctly placed revision tunnel. The first stage consisted of removal of the old graft and interfering metalwork, together with bone grafting of the tibial tunnel. After ensuring adequate bone graft incorporation using computed tomography scan, the second stage revision was undertaken. This stage comprised harvesting the autograft, its anatomical placement, and its adequate fixation. The results were compared with the results of a matched group of patients with primary anterior cruciate ligament reconstruction (group P). RESULTS: In group R, as meniscal and chondral lesions were more common, the International Knee Documentation Committee scores were lower than those of group P (61.2 for group R and 72.8 for group P; P = .006). Objective laxity measurement was similar in both groups (1.36 mm for group R and 1.2 mm for group P; P = .25). CONCLUSION: This study establishes that the laxity measurements achieved with a 2-stage revision anterior cruciate ligament reconstruction can be similar to those achieved after primary anterior cruciate ligament reconstruction, although the International Knee Documentation Committee rating is lower.     

Posterior cruciate ligament reconstruction using single-bundle patella tendon graft with tibial inlay fixation: 2- to 10-year follow-up

PURPOSE: Reconstruction of the posterior cruciate ligament (PCL) using the tibial inlay fixation has been reported as an alternative to the transtibial tunnel technique. Previous failures in PCL reconstruction and early reports raising potential biomechanical and clinical advantages have spurred interest in this technique. The purpose of this study was to evaluate the minimum 2-year results of PCL reconstruction using a single-bundle bone-patellar tendon-bone graft and tibial inlay fixation. METHODS: The authors prospectively studied 44 patients having isolated or combined PCL reconstruction using the direct tibial inlay fixation technique. The study period was from 1991 to 2001. Two-year minimum follow-up was 93% (41/44) and averaged 39.4 months. These 41 patients comprised the study group. Thirty-one patients were male and 10 patients were female; average age was 28 years. There were 35 primary and 6 revision reconstructions. Surgery was performed in the acute or subacute setting (<8 weeks) in 34% (14/41) and chronic setting in 66% (27/41). Combined reconstructions involving the posterolateral corner, anterior cruciate ligament (ACL), or medial collateral ligament (MCL) were done in 85% (35/41). In all patients, preoperative posterior drawer (PD) examination demonstrated greater than 12 mm posterior translation. All PCL reconstructions were performed with bone-patellar tendon-bone graft, which was 12 to 18 mm in width (16 autograft; 25 allograft). Wider tendon grafts were prepared from the allografts and tubularized to fit through an 11-mm tunnel. All patients were evaluated with preoperative and postoperative examination and x-rays. Final follow-up International Knee Documentation Committee (IKDC) subjective evaluation, final follow-up IKDC objective evaluation, and final follow-up Telos stress radiography were performed in all patients. RESULTS: Postoperative PD examination demonstrated the following: 0 (normal) in 9 patients, 1+ in 25 patients, 2+ in 7 patients, and none >2+, as compared to preoperative PD 3+ or greater in all patients in this report. No patient had <12 mm PD preoperatively. Mean improvement in PD was >2 grades of translation as compared to preoperative exam. Forty of forty-one demonstrated a solid endpoint on clinical PD testing. Final follow-up Telos stress radiography with 25 kg posterior load applied at 80 degrees to 90 degrees of flexion demonstrated average side-to-side difference of 4.11 mm (-2 to 10 mm). Average flexion loss was 4 degrees (0-15 degrees ). None lost extension. Preoperative IKDC objective evaluation rated all knees as severely abnormal based on instability. Final follow-up objective IKDC evaluation distribution was as follows: A, 4 knees; B, 24 knees; C, 11 knees; and D, 2 knees, as compared to all 41 D preoperatively. Average final follow-up IKDC subjective score was 75.1 (20-100). When assessing final follow-up stability with Telos stress radiography, primary cases were significantly more stable than revision cases (P <.05). There was no difference in stability when comparing allograft versus autograft, but improved IKDC scores were seen with allograft (P <.05). There was a trend for combined reconstructions to be more stable than isolated reconstructions. All patients evaluated their knee as improved or greatly improved and would repeat the procedure. CONCLUSIONS: Reconstruction of the PCL-deficient knee with severe posterior laxity is a challenging surgical problem, as combined instability patterns frequently coexist (85% in this study). When appropriate combined reconstructions or primary repair is used, PCL reconstruction with autologous or allograft bone-patellar tendon-bone graft using tibial inlay fixation was shown to be a successful technique at 2- to 10-year follow-up. Based on their initial experience with this technique and previous experience with open and arthroscopic techniques using a transtibial tunnel, the authors continue to use the tibial inlay technique as their preferred technique for isolated or combined reconstruction of the PCL.     

Comparison of the bioabsorbable and metal screw fixation after ACL reconstruction with a hamstring autograft in MRI and clinical outcome: a prospective randomized study

There has never been an MRI study of tunnel widening comparing bioabsorbable to metal screw fixation in autologous hamstring anterior cruciate ligament (ACL) reconstruction. We randomized 62 patients to hamstring ACL reconstruction with either a bioabsorbable (n = 31) or metal screw (n = 31) fixation. The evaluation methods were clinical examination, KT-1000 arthrometric measurement, the International Knee Documentation Committee and Lysholm scores, and MRI. There were no differences between the groups preoperatively. Fifty-five patients (89%) were available at a minimum of 2-year follow-up (range 24–36 months). There was tunnel widening in both groups, but the increase was significantly greater in the AP dimension of the femoral tunnel in the bioabsorbable screw group compared to metal group (P = 0.01). The tibial tunnels showed no intergroup difference. Ninety-four percent of the knees were normal or nearly normal according to the IKDC scores and the average Lysholm score was 91 with no intergroup difference. The follow-up AP tibial tunnel diameter was smaller with normal knee laxity compared to abnormal knee laxity. The graft failure rate in the bioabsorbable screw group was 23% (7/31 patients) and 6% (2/31 patients) in the metal screw group. The use of bioabsorbable screws resulted in more femoral tunnel widening, and more graft failures compared to metal screws. The tunnel widening in the tibia was associated with the knee laxity (P = 0.02).     

Functional outcome after computer-assisted versus conventional total knee arthroplasty: a randomized controlled study

Despite the frequent use of computer-assisted total knee arthroplasty (TKA) and better radiological results for coronal alignment reported in many studies, there is still no evidence of improved clinical outcomes when compared to conventional TKA. We compared alignment after navigated TKA and conventional TKA in 80 randomized patients. Seventy three patients were available for physical and radiological examination at 20 month after surgery. Both groups showed similar Knee Society Score results, with medians of 89 points (navigated 49–95 points, conventional 48–95 points, n.s.) in the Knee Score and 70 points (navigated 45–100 points, conventional 40–100 points, n.s.) in the Function Score. The median improvement in the Knee Society Knee Score was 45 points (−3 to 88 points) in the navigated group and 35 points (−13 to 62 points) in the conventional group (P = 0.03), and the Knee Society Function Score improvement was 15 points (−10 to 50 points) in the navigated group versus 10 points (−10 to 50 points) in the conventional group (n.s.). The current health state at follow-up using the EuroQuol questionnaire was similar in both groups, with medians of 67 points in the navigated group and 65 points in the conventional group. This investigation did show slightly greater functional improvement at short-term follow-up in the navigated TKA group. Longer follow-up will be required to assess the possible benefit of computer-assisted navigation.     

Tibiofemoral kinematics following successful anterior cruciate ligament reconstruction using dynamic multiple resonance imaging

BACKGROUND: The aim of anterior cruciate ligament reconstruction is to reduce excess joint laxity, hoping to restore normal tibiofemoral kinematics and therefore improve joint stability. It remains unclear if successful ACL reconstruction restores normal tibiofemoral kinematics and whether it is this that is associated with a good result. STUDY: Case series. PURPOSE: To assess the kinematics of the anterior cruciate ligament-reconstructed knee using open-access MRI. METHODS: Tibiofemoral motion was assessed using open-access MRI, weightbearing through the arc of flexion from 0 degrees to 90 degrees in 10 patients with isolated reconstruction of the anterior cruciate ligament (hamstring autograft) in one knee and a normal contralateral knee. Midmedial and midlateral sagittal images were analyzed in all positions of flexion in both knees to assess the tibiofemoral relationship. Sagittal laxity was also assessed by performing the Lachman test while the knees were scanned dynamically using open-access MRI. RESULTS: The amount of excursion between the tibial and femoral joint surfaces was similar between the normal and reconstructed knees, but the relationship of tibia to femur was always different for each position of knee flexion assessed-the lateral tibia being about 5 mm more anterior in the anterior cruciate ligament-reconstructed knees. This anterior tibial position is statistically significantly different at 0 degrees (P <.0006), 20 degrees (P =.0004), 45 degrees (P =.002), and 90 degrees of flexion (P <.006). Anteroposterior laxity was similar between normal and anterior cruciate ligament-reconstructed knees. CONCLUSION: Anterior cruciate ligament reconstruction reduces sagittal laxity to within normal limits but does not restore normal tibiofemoral kinematics despite a successful outcome.     

Anterior cruciate ligament revision reconstruction: results using a quadriceps tendon-patellar bone autograft

BACKGROUND: The quadriceps tendon is a viable graft source for revision anterior cruciate ligament reconstruction. PURPOSE: To determine the functional results and graft failure rates in knees in which the patellar tendon had been previously harvested or was unavailable, expanded tunnels precluded the use of a semitendinosus-gracilis graft, or patients requested autogenous tissues instead of allografts for revision reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The authors observed 21 patients for a mean of 49 months postoperatively after revision anterior cruciate ligament reconstruction with a quadriceps tendon graft. The results were determined by KT-2000 arthrometer testing, the Cincinnati Knee Rating System, and the International Knee Documentation Committee Rating System. Fifteen knees required a concurrent procedure, including reconstruction of posterolateral structures in 5 knees, meniscal repairs in 5 knees, and high tibial osteotomy in 2 knees. RESULTS: Significant improvements occurred in symptoms (P < .0001), daily activities (P < .05), sports activities (P < .01), and the overall rating scores (P < .0001). Eighteen patients rated their knee condition as improved. Total mean anterior-posterior displacements decreased from 8.4 +/- 3.1 mm preoperatively to 2.0 +/- 2.3 mm at follow-up (P < .001). On the International Knee Documentation Committee knee ligament rating, 17 knees were graded as normal or nearly normal, 3 were graded as abnormal, and 1 was graded as severely abnormal. CONCLUSION: The revision operation provided reasonable results in this group of complex knees. However, the functional and overall results were inferior to those reported for primary anterior cruciate ligament reconstruction. Many knees (90%) had compounding problems of articular cartilage damage, meniscectomy, varus malalignment, or additional ligamentous injury that most likely affected the results.     

前交叉韧带重建术后假体功能不全的影像评价

目的 探讨前交叉韧带重建术后假体功能不全的影像特点.方法 同顾性分析24例韧带重建术后因功能不全而接受二次关节镜的患者,包括16例假体断裂,8例假体松弛.影像评价包括骨道关节内口的位置、韧带假体的MRI表现、骨关节病程度及相关并发症.假体断裂组和松弛组的骨道内口位置、MRI表现为断裂的比例及骨关节病等的比较,采用Fisher精确概率法比较.结果 断裂组中,2例股骨骨道关节内口位置异常,3例胫骨骨道关节内口位置异常;松弛组中,3例股骨骨道关节内口位置异常,4例胫骨骨道关节内口位置异常.两组间比较,股骨骨道关节内口位置异常(P=0.289)和胫骨骨道关节内口位置异常的比例(P=0.167)差异均无统计学意义.断裂组中,MRI正确诊断15例完全断裂,1例部分断裂表现为正常;松弛组中,4例表现为正常,其余4例在MRI上被诊断为假体断裂.两组在MRI上表现为断裂的比例差异存在统计学意义(P =0.028).断裂组中,14例可见骨关节病;松弛组中,5例可见骨关节病.两组骨关节病的比例差异无统计学意义(P=0.289).结论 假体断裂和假体松弛骨道关节内口位置异常和骨关节病的比例差异无统计学意义;MRI可以正确诊断绝大多数假体断裂,而部分假体松弛则容易被误诊为假体断裂.     

Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length

Tibial bone tunnels were examined with bone scans 2 years after patella ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r = 0.64, P < 0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r = 0.59 P < 0.001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation is more than 14 mm below the joint.     

A 10-year comparison of anterior cruciate ligament reconstructions with hamstring tendon and patellar tendon autograft: a controlled, prospective trial

BACKGROUND: There are no controlled, prospective studies comparing the 10-year outcomes of anterior cruciate ligament (ACL) reconstruction using patellar tendon (PT) and 4-strand hamstring tendon (HT) autografts. HYPOTHESIS: Comparable results are possible with HT and PT autografts. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: One hundred eighty ACL-deficient knees that met inclusion criteria underwent ACL reconstruction (90 HT autograft, 90 PT autograft) by one surgeon and were treated with an accelerated rehabilitation program. All knees were observed in a prospective fashion with subjective, objective, and radiographic evaluation at 2, 5, 7, and 10-year intervals. RESULTS: At 10 years, there were no differences in graft rupture rates (7/90 PT vs. 12/90 HT, P = .24). There were 20 contralateral ACL ruptures in the PT group, compared with 9 in the HT group (P = .02). In all patients, graft rupture was associated with instrumented laxity >2 mm at 2 years (P = .001). Normal or near-normal function of the knee was reported in 97% of patients in both groups. In the PT group, harvest-site symptoms (P = .001) and kneeling pain (P = .01) were more common than in the HT group. More patients reported pain with strenuous activities in PT knees than in HT knees (P = .05). Radiographic osteoarthritis was more common in PT knees than the HT-reconstructed knees (P = .04). The difference, however, was composed of patients with mild osteoarthritis. Other predictors of radiographic osteoarthritis were <90% single-legged hop test at 1 year and the need for further knee surgery. An "ideal" outcome, defined as an overall International Knee Documentation Committee grade of A or B and a radiographic grade of A at 10 years after ACL reconstruction, was associated with <3 mm of instrumented laxity at 2 years, the absence of additional surgery in the knee, and HT grafts. CONCLUSIONS: It is possible to obtain excellent results with both HT and PT autografts. We recommend HT reconstructions to our patients because of decreased harvest-site symptoms and radiographic osteoarthritis.     

The effect of graft placement on the clinical outcome of the anterior cruciate ligament reconstruction: a prospective study

The effect of the graft placement on the clinical outcome of patients after anterior cruciate ligament (ACL) reconstruction has been studied sparsely. We conducted a prospective follow-up of 140 patients who underwent an arthroscopic ACL reconstruction with a hamstring graft. One hundred and four of them (74%) could be examined at the 2-year follow-up. Clinical examination included Lysholm, Tegner, and International Knee Documentation Committee rating scores, arthrometric anterior–posterior knee laxity assessment, and muscle strength assessments. The graft placement was measured from lateral radiographs using a system recommended for measuring the attachment positions of the cruciate ligaments as well as a method called ‘the sumscore of the graft placement’, which takes into account both the femoral and the tibial graft placements simultaneously. The sumscore was smaller in knees with normal anterior–posterior knee laxity in the Lachman test (P = 0.002) and normal rotational knee laxity in the pivot shift test (P = 0.01) than in those with abnormal laxity. The tibial graft placement was more anterior when the Lachman test was normal (P = 0.04). The Lysholm score was better when the femoral graft placement was more posterior (r = −0.20, P = 0.04). The optimal femoral graft placement was between 25 and 29% of length of the femoral condyle along the Blumensaat’s line from posterior to anterior. The optimal tibial graft placement was between 32 and 37% of the length of the tibial plateau from the anterior corner, and the optimal sumscore was between 61 and 66. The sumscore and its components (the femoral and tibial graft placements) showed a clear association with the clinical outcome of the patients. The best outcome was achieved when the sumscore was small; that is the graft placement showed posterior enough in the femur, and anterior enough in the tibia.     

Popliteofibular ligament reconstruction for posterolateral external rotation instability of the knee

The aim of this study was to assess the clinical outcome of popliteofibular ligament (PFL) reconstruction for posterolateral external rotation instability of the knee. PFL reconstruction was performed consecutively in 22 patients with chronic external rotation instability of the knee. The inclusion criterion for surgery was tibial external rotation of 10° more than the contralateral uninjured knee without varus laxity. A double bone tunnel was created at the PFL insertion of the fibular head through the lateral incision of the knee joint and a single bone tunnel at the popliteus tendon insertion on the femoral side. A semitendinosus autograft tendon or tibialis anterior allograft tendon was introduced through the fibular tunnel as a loop, then both free ends of the graft were introduced through the femoral tunnel and a bioabsorbable interference screw was used to fix the graft. The minimum follow-up was 2 years. Clinical review included the International Knee Documentation Committee (IKDC) scale and tibial external rotation assessment. All patients’ preoperational tibial external rotation averaged 15° more than the contralateral uninjured knee. operatively the tibial external rotation was decreased, average −3° compared with the contralateral side. This difference was statistically significant. The final IKDC grades were: 22 cases with grade D preoperatively, and 6 were grade A, 8 were grade B, 7 were grade C and 1 was grade D postoperatively. In this small clinical series, PFL reconstruction technique was shown to correct pathological excessive tibial external rotation.     

Physiological anterior laxity in healthy young females: the effect of knee hyperextension and dominance

Female athletes are more likely to sustain an anterior cruciate ligament (ACL) injury. Knee laxity, hyperextension and limb dominance have been suggested as possible factors contributing to the knee injury. The aims of this study were to investigate the physiological anterior knee laxity between the dominant and non-dominant limb and in healthy young females with and without hyperextension knees. Forty-two healthy young females, 21 with hyperextension knees, were recruited voluntarily for this study. The subjects were tested with KT-2000 knee ligament arthrometer at both knees with flexion 30° to obtain the anterior tibial displacements at loadings of 45, 67, 89 and 134 N. The initial and terminal stiffnesses were further calculated and analyzed to demonstrate the differences in the characteristics of knee laxity between limbs and groups. The results showed that there was no significant displacement difference between hyperextension and non-hyperextension groups. However, different physiological anterior laxities were illustrated for the different limbs and groups. The non-dominant side of the hyperextension group had significantly smaller terminal stiffness than that of the non-hyperextension group. The dominant side of the hyperextension group had larger laxity than the non-dominant side in the higher loading conditions. These findings may explain hyperextension knees are at greater risk of sustaining an ACL injury.     

Differences in torsional joint stiffness of the knee between genders: a human cadaveric study

BACKGROUND: In many sports, female athletes have a higher incidence of anterior cruciate ligament injury than do male athletes. Among many risk factors, the lower rotatory joint stiffness of female knees has been suggested for the increased rate of anterior cruciate ligament injuries. HYPOTHESIS: In response to combined rotatory loads, female knees have significantly lower torsional joint stiffness and higher rotatory joint laxity than do male knees at low flexion angles, despite the fact that no such gender differences would be found in response to an anterior tibial load. STUDY DESIGN: Comparative laboratory study. METHODS: Joint kinematics of 82 human cadaveric knees (38 female, 44 male) in response to (1) combined rotatory loads of 10 N x m valgus and +/- 5 N x m internal tibial torques and (2) a 134-N anterior-posterior tibial load were measured using a robotic/universal force-moment sensor testing system. RESULTS: In response to combined rotatory loads, female knees had as much as 25% lower torsional joint stiffness (female: 0.79 N x m/deg; 95% confidence interval, 0.67-0.91; male: 1.06 N x m/deg; 95% confidence interval, 0.95-1.17) and up to 35% higher rotatory joint laxity (female: 26.2 degrees; 95% confidence interval, 24.5 degrees-27.9 degrees; male: 20.5 degrees; 95% confidence interval, 18.8 degrees-22.2 degrees) than did male knees (P < .05), whereas there were no gender differences in response to the anterior tibial load (P > .05). CONCLUSION: Female knees had lower torsional joint stiffness and higher rotatory joint laxity than did male knees in response to combined rotatory loads. CLINICAL RELEVANCE: Larger axial rotations of female knees in response to rotatory loads may affect the distribution of forces in soft tissues and the function of muscles that provide knee stability. Control algorithms used during the biomechanical testing of cadaveric knees and computational knee models might need to be gender specific.     

A randomized comparison of patellar tendon and hamstring tendon anterior cruciate ligament reconstruction

BACKGROUND: Patellar and hamstring tendon autografts are the most frequently used graft types for anterior cruciate ligament reconstruction, but few direct comparisons of outcomes have been published. HYPOTHESIS: There is no difference in outcome between the two types of reconstruction. STUDY DESIGN: Prospective randomized clinical trial. METHODS: After isolated anterior cruciate ligament rupture, 65 patients were randomized to receive either a patellar tendon or a four-strand hamstring tendon graft reconstruction, and results were reviewed at 4, 8, 12, 24, and 36 months. RESULTS: Pain on kneeling was more common and extension deficits were greater in the patellar tendon group. There were greater quadriceps peak torque deficits in the patellar tendon group at 4 and 8 months but not thereafter. In the hamstring tendon group, active flexion deficits were greater from 8 to 24 months, and KT-1000 arthrometer side-to-side differences in anterior knee laxity at 134 N were greater. Cincinnati knee scores, International Knee Documentation Committee ratings, and rates of return to preinjury activity levels were not significantly different between the two groups. CONCLUSIONS: Both grafts resulted in satisfactory functional outcomes but with increased morbidity in the patellar tendon group and increased knee laxity and radiographic femoral tunnel widening in the hamstring tendon group.     

Kinematics and laxity of the knee joint after anterior cruciate ligament reconstruction: pre- and postoperative radiostereometric studies

BACKGROUND: Injury of the anterior cruciate ligament changes the kinematics of the knee joint. In studies of cadaveric knees, investigators have examined the effect of anterior cruciate ligament reconstruction on knee kinematics, but the effect on dynamic knee motion is not known. HYPOTHESIS: Reconstruction of the anterior cruciate ligament restores knee kinematics to normal. STUDY DESIGN: Prospective cohort study. METHODS: Nine patients were examined preoperatively and 1 year after reconstruction. Continuous radiostereometric exposures were performed at a speed of two to four exposures per second while the patients ascended an 8-cm high platform. Tibial rotation and tibial and femoral translation were measured with radiostereometric analysis. RESULTS: Tibial rotation and tibial and femoral translation were not significantly different after anterior cruciate ligament reconstruction compared with preoperative measurements. A radiostereometric evaluation of anterior knee laxity revealed restoration to within 1 mm of that on the uninjured side. Further evaluation of knee function using the Lysholm score, the Tegner activity level score, the International Knee Documentation Committee evaluation system score, and measurements of laxity using the KT-1000 arthrometer revealed significant improvements after reconstruction. CONCLUSION: Kinematics of the anterior cruciate ligament injured knee did not change significantly after ligament reconstruction, but the functional results were satisfactory and knee laxity was diminished.     

Bilateral anterior cruciate ligament reconstruction as a single procedure: evaluation of cost and early functional results

BACKGROUND: The ideal treatment for patients presenting with bilateral anterior cruciate ligament (ACL) deficiency remains controversial. PURPOSE: To evaluate cost and early functional results after bilateral ACL reconstruction at a single setting. STUDY DESIGN: Retrospective review. METHODS: Eleven patients (22 knees) who underwent bilateral ACL reconstruction at a single setting were compared with 33 patients (35 knees) who underwent unilateral ACL reconstruction during the same time period. RESULTS: The mean time to full unrestricted activity between groups was 6.5 months for both groups (P = 0.92). There were no significant differences between groups at latest follow-up for complication rates or laxity as judged by Lachman test, pivot shift test, and KT 1000 arthrometry. The mean International Knee Documentation Committee subjective score at a mean 3.1-year follow-up was 91.9 for the bilateral ACL group compared to 92.0 for the unilateral ACL group (P = 0.95). There was a total cost savings per knee (based on 2001 dollars) of $3751.59 when performing bilateral ACL reconstruction at a single setting (P = 0.0001). CONCLUSIONS: For patients presenting with bilateral ACL deficient knees, reconstruction of both knees at a single setting is safe, cost effective, and does not appear to compromise early functional results.     

Varying femoral tunnels between the anatomical footprint and isometric positions: effect on kinematics of the anterior cruciate ligament-reconstructed knee

BACKGROUND: Knee kinematics and in situ forces resulting from anterior cruciate ligament reconstructions with 2 femoral tunnel positions were evaluated. HYPOTHESIS: A graft placed inside the anatomical footprint of the anterior cruciate ligament will restore knee function better than a graft placed at a position for best graft isometry. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric knees were tested in response to a 134-N anterior load and a combined 10-N.m valgus and 5-N.m internal rotation load. A robotic universal force-moment sensor testing system was used to apply loads, and resulting kinematics were recorded. An active surgical robot system was used for positioning tunnels in 2 locations in the femoral notch: inside the anatomical footprint of the anterior cruciate ligament and a position for best graft isometry. The same quadrupled hamstring tendon graft was used for both tunnel positions. The 2 loading conditions were applied. RESULTS: At 30 degrees of knee flexion, anterior tibial translation in response to the anterior load for the intact knee was 9.8 +/- 3.1 mm. Both femoral tunnel positions resulted in significantly higher anterior tibial translation (position 1: 13.8 +/- 4.6 mm; position 2: 16.6 +/- 3.7 mm; P < .05). There was a significant difference between the 2 tunnel positions. At the same flexion angle, the anterior tibial translation in response to the combined load for the intact knee was 7.7 +/- 4.0 mm. Both femoral tunnel positions resulted in significantly higher anterior tibial translation (position 1: 10.4 +/- 5.5 mm; position 2: 12.0 +/- 5.2 mm; P < .05), with a significant difference between the tunnel positions. CONCLUSION: Neither femoral tunnel position restores normal kinematics of the intact knee. A femoral tunnel position inside the anatomical footprint of the anterior cruciate ligament results in knee kinematics closer to the intact knee than does a tunnel position located for best graft isometry. CLINICAL RELEVANCE: Anatomical femoral tunnel position is important in reproducing function of the anterior cruciate ligament.     

Anterior cruciate ligament reconstruction using autografts and double biodegradable femoral cross-pin fixation: functional,radiographic and MRI outcome after 2-year minimum follow-up

Double biodegradable cross-pins are increasingly used for femoral fixation in arthroscopically assisted reconstruction of the anterior cruciate ligament (ACL). There are no studies combining functional outcome analysis, radiographs and magnetic resonance images (MRI) to evaluate this technique. The authors examined 45 patients after ACL reconstruction using double biodegradable femoral cross-pin fixation and biodegradable tibial interference screw fixation with a minimum follow-up of 24 months. Clinical evaluation included International Knee Documentation Committee (IKDC) and modified Lysholm score. Radiographic analysis included standard X-rays in anterior–posterior and lateral views and Telos stress device measurements. MRI was analyzed to obtain information about hardware, intra-articular graft, osseous graft-integration and cartilage. IKDC score revealed 28 (62.2%) patients with normal knee function (group A), 15 (33.3%) patients with nearly normal (group B) knee function and 2 (4.4%) patients with abnormal knee function (group C). The Lysholm score was 94.6 (±7.2) in the operated knee and 98.8 (±7.4) in the non-operated knee. Mean Telos stress device values were +4.6 (±2.6) in the operated and +3.9 (±2.4) in the non-operated knee. MRI showed an intact intra-articular graft in all but one patient. Complete femoral graft integration was seen in 88.9% and complete tibial graft integration in 86.7%. Biodegradable cross-pins were partially or fully visible in all patients. The biodegradable tibial interference screw was fully visible in 16 (35.6%) and partially visible in 20 (44.4%) patients. Thirty-one (68.9%) patients showed signs of cartilage degeneration on MRI at follow-up. The graft fixation with double biodegradable pin fixation appears to be a reliable technique for ACL reconstruction providing a stable close-to-joint graft fixation.     

Intercondylar roof impingement pressure after anterior cruciate ligament reconstruction in a porcine model

Anterior cruciate ligament (ACL) graft impingement against the intercondylar roof has been postulated, but not thoroughly investigated. The roof impingement pressure changes with different tibial and femoral tunnel positions in ACL reconstruction. Anterior tibial translation is also affected by the tunnel positions of ACL reconstruction. The study design included a controlled laboratory study. In 15 pig knees, the impingement pressure between ACL and intercondylar roof was measured using pressure sensitive film before and after ACL single bundle reconstruction. ACL reconstructions were performed in each knee with two different tibial and femoral tunnel position combinations: (1) tibial antero-medial (AM) tunnel to femoral AM tunnel (AM to AM) and (2) tibial postero-lateral (PL) tunnel to femoral High-AM tunnel (PL to High-AM). Anterior tibial translation (ATT) was evaluated after each ACL reconstruction using robotic/universal force-moment sensor testing system. Neither the AM to AM nor the PL to High-AM ACL reconstruction groups showed significant difference when compared with intact ACL in roof impingement pressure. The AM to AM group had a significantly higher failure load than PL to High-AM group. This study showed how different tunnel placements affect the ACL-roof impingement pressure and anterior-posterior laxity in ACL reconstruction. Anatomical ACL reconstruction does not cause roof impingement and it has a biomechanical advantage in ATT when compared with non-anatomical ACL reconstructions in the pig knee. There is no intercondylar roof impingement after anatomical single bundle ACL reconstruction.     

Posterior instability near extension is related to clinical disability in isolated posterior cruciate ligament deficient patients

The purpose of this study is to evaluate the relationship between the magnitude of knee laxity and posterior instability at different knee flexion angles and clinical disability in isolated posterior cruciate ligament (PCL) deficient patients. Knee laxity at 20° and 70° of knee flexion were evaluated using KT-2000 arthrometer, and the posterior instability at 20°, 45° and 90° of flexion were evaluated using stress radiography. We assessed the differences in the knee laxity and the tibial translation between isolated PCL deficient knees and normal knees, and between the patients with giving-way during activities of daily living (ADL) and without giving-way. There were statistical differences in the knee laxity and the tibial translation at all knee flexion angles between the PCL deficient knees and normal knees. The magnitude of the knee laxity at 20° of flexion measured with KT-2000 arthrometer was significantly larger in the patients with giving-way than those in the patients without giving-way although there was no significant difference in the tibial translation at 70° between the two groups. The tibial translation in both medial and lateral compartments at 20° and 45° measured with stress radiography were significantly larger in the patients with giving-way than those in the patients without giving-way although there was not significant difference at 90° between the two groups. These results suggested that the magnitude of the knee laxity and the posterior tibial translation at shallow knee flexion angles would be related to giving-way during ADL in isolated PCL deficient patients.