KT-1000 Measurements Research Articles

The Use of an Electromagnetic Measurement System for Anterior Tibial Displacement During the Lachman Test

The purpose of this study was to assess quantitative anterior/posterior values during the Lachman test by an electromagnetic measurement system and to compare data with KT-1000 arthrometric measurements (MEDmetric, San Diego, CA), as well as the measurement of radiologic laxity by dynamic radiographs. We used an electromagnetic device to quantitatively evaluate anterior knee displacements. We tested 82 knees in 41 patients (30 isolated anterior cruciate ligament [ACL]-deficient, 11 ACL-reconstructed, and 41 contralateral ACL-intact knees). Anterior displacements during the Lachman test were calculated by the electromagnetic measurement system and fluoroscopic measurement, and anterior displacements were also measured by the KT-1000 arthrometer. Anterior/posterior displacements measured by these methods were compared, and correlations were assessed. In ACL-deficient knees, mean anterior/posterior displacement (±SE) was 22.4 ± 0.8 mm in electromagnetic measurements, 22.0 ± 0.7 mm in fluoroscopic measurements, and 15.0 ± 0.6 mm in KT-1000 measurements. In contralateral ACL-intact knees, it was 15.7 ± 0.6 mm, 15.6 ± 0.5 mm, and 9.9 ± 0.4 mm, respectively. In ACL-reconstructed knees, it was 15.7 ± 0.7 mm, 16.2 ± 0.8 mm, and 11.2 ± 0.6 mm, respectively. In all knee conditions, significant differences between fluoroscopic measurements and KT-1000 measurements were detected (P < .01). Significant differences were also detected between electromagnetic measurements and KT-1000 measurements (P < .01). No significant differences were detected between fluoroscopic measurements and electromagnetic measurements. A strong correlation was obtained between KT-1000 measurements and fluoroscopic measurements (r = 0.62, P < .01) and between electromagnetic measurements and KT-1000 measurements (r = 0.64, P < .01). However, the strongest correlation was observed between electromagnetic measurements and fluoroscopic measurements (r = 0.96, P < .01). An electromagnetic measurement system to test anterior/posterior tibial translation determined that quantification of the Lachman test could be performed as accurately as fluoroscopic measurements. Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.

The use of the LARS artificial ligament to augment a short or undersized ACL hamstrings tendon graft

The aim of this study is to evaluate the midterm results of using Ligament Advanced Reinforcement System (LARS) artificial ligament for augmentation of the short (< 15 cm length) and small-sized (3–4 mm) diameter for the gracilis and (4–5 mm) for the semitendinosus harvested hamstring tendons in anterior cruciate ligament (ACL) reconstruction, and to assess the knee stability, patient satisfaction and early- and midterm complications following surgery. A total of 112 patients were included in this study and were operated with arthroscopic ACL reconstruction using (augmented hamstring tendon graft with LARS) between January 2004 and December 2006. Assessment before and after the surgery include the history, clinical examination, modified international knee documentation committee score (IKDC), KT1000 measurements for clinical knee stability and osteoarthritis outcome score (KOOS) for patient satisfaction. Clinical results measured by IKDC evaluation, KT1000 and Lysholm scores showed significant postoperative values compared with the preoperative ones. Our findings suggest that at the end of a 5-year follow-up, augmented hamstring tendon graft with LARS artificial ligament is a useful, safe and satisfactory treatment option for ACL reconstruction in deficient knees with short- and small-sized harvested hamstring tendons, especially when an early return to high levels of sport activity is needed.

A prospective randomised study of anatomical single-bundle versus double-bundle anterior cruciate ligament reconstruction: quantitative evaluation using an electromagnetic measurement system

We conducted a prospective randomised study of anatomical single-bundle (A-SB group) versus double-bundle (A-DB group) anterior cruciate ligament (ACL) reconstruction using the hamstrings tendons. Twenty patients with unilateral ACL deficiency were randomised into two groups. We created the bone tunnels at the position of the original insertion of the anteromedial bundle footprint and posterolateral bundle footprint in the A-DB group and at the central position between these two bundles in the A-SB group. All of the patients were tested before ACL reconstruction and one year after surgery. The KT-1000 measurements, isokinetic muscle peak torque and heel-height difference were evaluated and the general knee condition was assessed by Lysholm score. For pre- and postoperative stability assessment, we used the six-degrees-of-freedom of knee kinematic measurement system using an electromagnetic device (the EMS) for quantitative assessment during the Lachman test and the pivot shift test. There were no significant differences in the KT-1000 measurements, isokinetic muscle peak torque, heel-height difference, and Lysholm score at one-year follow-up between these two groups. The EMS data showed there were significant differences in the acceleration of the pivot shift test between the operated knee and the contralateral normal knees in the A-SB group. In conclusion, clinical outcomes were equally good in both groups. However, the EMS data showed the anatomical double-bundle ACL reconstruction tended to be biomechanically superior to the single-bundle reconstruction.

No bone tunnel enlargement in patients with open growth plates after transphyseal ACL reconstruction

Bone tunnel enlargement after ACL reconstruction has been described extensively in adults. However, little is known about this phenomenon in patients with open growth plates. Thus, the goals of the current study were to evaluate changes in bone tunnel size in patients with open growth plates after transphyseal ACL reconstruction with suspensory fixation and to correlate tunnel size with clinical outcome after medium-term follow-up. Fourteen patients with open growth plates were included that underwent primary transphyseal ACL reconstruction using hamstrings autografts and suspensory fixation. Mean follow-up time was 7years. At the time of follow-up, MRIs of the operated knee were performed, and outcome was assessed using KOS-ADLS, Lysholm score, IKDC Subjective Knee Form score, Knee Examination Form score, and KT-1000 measurements. On MRI, the cross-sectional area of the bone tunnels was assessed using special axial cuts perpendicular to the axes of the tunnels. Two orthopaedic surgeons and two radiologists analysed the MRIs. Change in bone tunnel size from surgery to follow-up was calculated. No significant changes in bone tunnel size from surgery to follow-up were found. Regarding outcome measures, KOS-ADLS averaged 95%, Lysholm Score averaged 96 points, IKDC Subjective Knee Form averaged 95%, IKDC Knee Examination Form scores were 8A, 5B, 1C, and KT-1000 measurements averaged 1.8±1.4mm. No significant correlations were found between tunnel size at follow-up and outcome measures. Based on our study, bone tunnel enlargement does not occur in patients who have open growth plates and undergo ACL reconstruction using suspensory fixation.

Tibial tunnel widening after anterior cruciate ligament reconstructions with hamstring tendons using Rigidfix femoral fixation and Intrafix tibial fixation

The purpose of this study was to evaluate tibial tunnel widening prospectively after anterior cruciate ligament (ACL) reconstruction with hamstring tendon grafts using Rigidfix (DePuy Mitek, Raynham, MA) femoral fixation and Intrafix (DePuy Mitek) tibial fixation. Fifty-six consecutive patients who underwent ACL reconstruction with a minimum of 2 years' postoperative evaluation were reviewed. On the anterior-posterior (AP) and lateral radiographs, the diameter of the tibial tunnel was measured at proximal, middle, and distal positions, and the shape of the tibial tunnels were classified. Tunnel widening was defined as widening of greater than 2 mm. Group I was defined as cases with no tunnel widening, and group II was defined as cases with tunnel widening. Postoperative laxity evaluations were performed using Lachman test, pivot-shift test, and instrumented laxity testing using the KT-1000 arthrometer. On the AP radiographs, the average diameter of the tibial tunnel increased 8.8% at 6 months and 8.5% at 12 months postoperatively compared to the immediate postoperative day. On the lateral radiographs, the average diameter of the tibial tunnel increased 7.2% at 6 months and 8.1% at 12 months year postoperatively compared to the immediate postoperative day. The tunnel shape evaluation revealed predominantly linear type in 53 patients (95%). Group I was 42 patients (75%), and group II was 14 (25%). The average KT-1000 measurement was 1.0 +/- 1.8 mm in group I and 2.1 +/- 2.8 mm in group II (n.s.). The Lachman and pivot-shift tests showed no significant differences between the two groups. In conclusion, hamstring ACL reconstruction using Rigidfix and Intrafix fixation showed less widening of the tibial tunnels than observed in previously published studies.

Transphyseal Anterior Cruciate Ligament Reconstruction in Patients With Open Physes

The purpose of this study was to evaluate the clinical outcomes of transphyseal anterior cruciate ligament (ACL) reconstruction in patients with open physes. Transphyseal ACL reconstruction was performed in 26 patients with open tibial and femoral physes (physis >2 mm) by use of autogenous quadrupled hamstrings as grafts. Meniscal tearing was found in 65.3% of the patients. Partial chondral defect injury on the medial femoral condyle was found 6 months after injury in only 2 patients (7.69% of all patients). The mean follow-up period was 45 +/- 18.3 months. Clinical outcomes were evaluated by use of the International Knee Documentation Committee score and Lysholm Knee Scoring Scale, and the anteroposterior stability was objectively measured by use of KT-1000 arthrometer (MEDmetric, San Diego, CA). Possible length and angular discrepancies were observed by conventional radiography in a long film and scanograms of the lower limbs. The mean length discrepancy between the operated lower limb and the contralateral limb was 1.2 +/- 3.2 mm (range, -7 to 7 mm). The mean angular deviation difference between the lower limbs was 0.46 degrees +/- 1.1 degrees . New traumatic injuries developed in 3 patients, in whom surgical revision was performed; 1 patient underwent a late meniscectomy. The mean difference in KT-1000 measurement was 2.0 +/- 1.0 mm. The mean subjective International Knee Documentation Committee score was 91.5 +/- 5.7, and the mean score on the modified Lysholm scale was 93.5 +/- 4. Of the patients, 3 (11.2% of all patients) could not return to the same level of physical activity as before injury. ACL reconstruction by use of the transphyseal technique in an immature skeleton with a hamstring autograft, with careful attention being paid to the technique, resulted in good clinical outcomes and no growth abnormalities. Level IV, therapeutic case series.

In Vivo Magnetic Resonance Imaging Measurement of Tibiofemoral Relation With Different Knee Flexion Angles After Single- and Double-Bundle Anterior Cruciate Ligament Reconstructions

Double-bundle anterior cruciate ligament (ACL) reconstruction has been shown to restore better kinematics in vitro, but it is uncertain whether this technique can achieve this in vivo. We investigated whether anatomic double-bundle ACL reconstruction can restore a better tibiofemoral relation in the sagittal plane under static unloading conditions. The tibiofemoral relation was assessed with an open magnetic resonance imaging scanner (0.5 T) in 15 patients with anatomic double-bundle reconstruction (double-bundle group) and 14 patients with single-bundle reconstruction (single-bundle group) by use of hamstring tendons. T1-weighted magnetic resonance imaging for both knees was obtained at 0 degrees, 45 degrees, 90 degrees, and 120 degrees of flexion without external force and muscle contraction 6 months after surgery. The position of the posterior femoral condyles relative to the tibia was measured in the midmedial and midlateral sagittal sections of the knee. Clinical evaluation (range of motion, KT-2000 measurement [MEDmetric, San Diego, CA], and pivot-shift test) was performed at the same time. KT-2000 testing showed that the mean side-to-side difference in the double-bundle group (0.7 mm) was significantly smaller than that in the single-bundle group (1.7 mm). In the double-bundle group, the tibiofemoral relation in operated knees was not significantly different from that in the contralateral knees at 0 degrees, 45 degrees, 90 degrees, and 120 degrees of flexion, although at 0 degrees of flexion, the femoral condyles were positioned anteriorly relative to the tibia compared with that in the contralateral knees. Similar results were obtained in the single-bundle group. The difference in the tibiofemoral relation between reconstructed and contralateral knees was not significantly different between the 2 groups. According to KT-2000 measurement, this study found that anteroposterior stability was better with anatomic double-bundle ACL reconstruction than with single-bundle ACL reconstruction. However, under static conditions without an anterior drawer force, anatomic double-bundle ACL reconstruction did not show superiority in terms of restoring a better tibiofemoral relation compared with single-bundle ACL reconstruction. Level III, comparative study.

Analysis of Different Kinds of Cyclops Lesions With or Without Extension Loss

The purpose of this study was to retrospectively evaluate patients after anterior cruciate ligament (ACL) reconstruction in whom a cyclops lesion developed to seek the etiologic factors. From 1999 to 2005, we observed 48 cases of cyclops lesions in 311 cases arthroscopically while removing the internal fixation devices after ACL reconstruction. Before removing the hardware, the function of the knee was evaluated through symptoms, signs, radiography, and KT-2000 measurement (MEDmetric, San Diego, CA) in 311 cases. Histologic examination was performed on some of the resected lesions. Of the 311 patients, 45 were found to have nodular formations in the anterior part of the knee; this caused extension loss in 6 patients. Extension loss occurred at 2 to 3 months after ACL reconstruction. Histologic results were available in 18 patients (6 complained of a loss of extension and 12 were asymptomatic). Microscopic examination of the resected fibrous nodules showed disorganized fibrous connective tissue. We found that 8 nodules (4 with extension loss and 4 without extension loss) contained chondroid tissues, but we did not find osseous tissue in the nodules. The histologic appearance was similar to hypertrophic, degenerative granulation tissue. Among 311 second-look arthroscopies after ACL reconstruction, 45 cyclops lesions were found with a typical histology indicating an inflammatory proliferation with disorganized fibrous tissue, with some having chondroid tissue. Clinically, 10 patients had not returned to sporting activities: 6 of 6 who had extension loss and 4 of 39 who had full range of motion. All 6 patients with extension loss had full motion after resection of the cyclops lesion. Level IV, therapeutic case series.

Arthroscopic Fixation of Displaced Tibial Eminence Fractures: A New Growth Plate–Sparing Method

Fractures of the tibial eminence can be treated arthroscopically. Numerous ways to attach an anterior cruciate ligament avulsion from the tibial eminence have been designed. This report describes a new physis-sparing reduction and fixation technique using an anchor passing nonabsorbable braided sutures through the substance of the anterior cruciate ligament, holding the avulsed bone fragment by tying a locking knot. This study was performed to evaluate a consecutive group of patients who underwent reduction and fixation of tibial avulsion fractures fixed with an anchor with sutures. The evaluation was performed by use of objective and subjective International Knee Documentation Committee (IKDC) scores, KT-1000 measurement (MEDmetric, San Diego, CA), Lachman and pivot-shift tests, and Lysholm score. The global IKDC objective score was normal (A) in 4 knees and nearly normal (B) in 3, without extension or flexion limitations. The mean IKDC subjective score was 92 out of 100 (range, 86 to 98). The results of the anterior drawer, Lachman, and pivot-shift tests were negative. The mean Lysholm score improved from 29 to 94. The mean side-to-side difference in anterior tibial translation was 2 mm (range, 1 to 3 mm). Arthroscopic stabilization by use of an anchor with sutures was possible in all cases of tibial spine fracture. We were able to obtain excellent results in this series using this fixation method. Level IV, therapeutic case series.

Arthroscopic single-bundle posterior cruciate ligament reconstruction: retrospective review of hamstring tendon graft versus LARS artificial ligament

Our objective was to compare the results of reconstruction of isolated chronic posterior cruciate ligament (PCL) injury using a four-strand hamstring graft (4SHG) and a LARS artificial ligament. Thirty-six patients were divided into a 4SHG group (n = 15) and a LARS group (n = 21). The minimum follow-up time was two years. The outcome measures used were KT-1000 measurements, the International Knee Documentation Committee (IKDC) scoring system, Lysholm knee scoring scale and Tegner activity rating. Both groups improved significantly between the preoperative and postoperative assessment in terms of the knee laxity and functional examination (P < 0.01). Meanwhile, knee stability was significantly improved in the LARS group when compared with the 4SHG group (P < 0.05); this was also the case for the Lysholm, Tegner and IKDC scores (P < 0.05). Our study indicates that using a LARS ligament for PCL reconstruction was clinically more useful than using a 4SHG in the treatment of the PCL-deficient knee.

Arthroscopic Anterior Cruciate Ligament Reconstruction Utilizing Quadriceps Tendon Autograft: Intermediate Results (SS-32)

Arthroscopic Anterior Cruciate Ligament Reconstruction Utilizing Quadriceps Tendon Autograft: Intermediate Results (SS-32)

Oral Corticosteroid Use for Loss of Flexion After Primary Anterior Cruciate Ligament Reconstruction

Postoperative loss of motion after anterior cruciate ligament (ACL) reconstruction can lead to suboptimal outcomes. Short-term low-dose oral corticosteroids are an option for nonsurgical management of this condition. The purpose of this study is to retrospectively review a series of patients treated with a single Medrol Dosepak (MDP) (Pfizer, New York, NY) in the early postoperative period for the treatment of loss of flexion, focusing on range of motion, objective instrumented stability measurements, and complications. From September 1, 2003, through January 1, 2007, 28 (11%) of 252 patients who underwent primary ACL reconstruction were treated with an MDP at a mean of 6.1 weeks postoperatively (range, 4 to 12 weeks; SD, 1.4 weeks) for early postoperative loss of motion. Of these 28 patients, 4 were not included because of unavailable clinical records. One patient who underwent combined ACL and posterior cruciate ligament reconstruction with medial collateral ligament repair was excluded from the analysis. Range-of-motion and KT-1000 (MEDmetric, San Diego, CA) measurements were independently recorded by a single examiner preoperatively, at 6 weeks postoperatively, and again at final follow-up evaluation at a mean of 10.4 months (range, 4 to 24 months; SD, 4.3 months). The mean flexion deficit compared with the normal, contralateral knee at the time of treatment with an MDP was 31.3 degrees (range, -2 degrees to 55 degrees ; SD, 14.8 degrees ). Patients treated with an MDP showed a significant improvement in flexion deficit (mean, 29.2 degrees; range, 0 degrees to 60 degrees ; SD, 17.1 degrees ) after MDP treatment (P < .001). KT-1000 side-to-side differences at final examination were 2 mm or less in 22 of 23 patients (mean, 1 mm; range, 0 to 4 mm; SD, 1 mm). Of the 23 patients treated with an MDP, 5 (22%) were considered failures because they required surgical intervention for persistent loss of motion, resulting in a reoperation rate for loss of motion after primary ACL reconstruction of 2.0% (5/252). There were no documented complications of MDP treatment. Specifically, no patients treated with an MDP had a postoperative infection develop. The use of oral corticosteroids, in the form of an MDP, was associated with a successful return of normal range of motion in 78% of patients with early postsurgical loss of flexion and near-normal extension after primary ACL reconstruction without any associated complications or decrease in objective instrumented stability measurements. Level IV, therapeutic case series.

High Failure Rate for Electrothermal Shrinkage of the Lax Anterior Cruciate Ligament: A Multicenter Follow-up Past 2 Years

The purpose of this study was to prospectively evaluate the midterm results (beyond 2 years) of thermal shrinkage on both lax native anterior cruciate ligament (ACL) and lax reconstructions and determine the effectiveness of this procedure. This is a multicenter study in which 64 patients from 2 sites underwent electrothermal shrinkage for a lax ACL, both native and previous reconstructions. They were followed up past 2 years with KT-1000 measurements (MEDmetric, San Diego, CA). Failure criteria included subsequent operations for instability or KT-1000 measurements greater than 5 mm. Three patients were lost to follow-up. Among the 61 patients followed up past 2 years, failure occurred in 31 (50.8%). The failure rate for lax grafts alone was 78.9%, and there was a failure rate of 38.1% for lax native ligaments. Electrothermal shrinkage of lax native or reconstructed ACLs is not an appropriate treatment.

Do Broken Cross-Pins Compromise Stability After Anterior Cruciate Ligament Reconstructions With Hamstring Tendons?

The purpose of this prospective study was to define the relation between the integrity of cross-pin femoral fixation and stability after anterior cruciate ligament (ACL) reconstructions. Thirty-one consecutive ACL reconstructions were performed with hamstring tendons fixed with bioabsorbable cross-pin femoral fixation. All patients underwent magnetic resonance imaging at 6 months postoperatively to assess the status of the cross-pin fixation. Clinical evaluations were performed via the Lachman and pivot-shift tests. The side-to-side differences were measured by KT-1000 testing (MEDmetric, San Diego, CA) at 2 years postoperatively. The patients were divided into 2 groups according to the status of the cross-pin. Group I consisted of those in whom the cross-pins were intact, and group II had broken cross-pins. There were 19 patients in group I and 12 (38.7%) in group II. Among the 24 cross-pins used in the 12 patients in group II, 18 were broken. Among the patients in group I, the tip of the cross-pin was inside the posterior cortex of the distal femur in 7 (36.8%) and outside in 12 (63.2%). In group II the tip of the cross-pin was outside the posterior cortex of the distal femur in all patients. This number was significantly higher than that in group I (P = .017). Group I had significantly lower KT-1000 measurements than group II (P = .003). The mean KT-1000 side-to-side difference was 0.47 mm in group I and 3.0 mm in group II. The Lachman and pivot-shift test data revealed no significant differences between the 2 groups (P = .467 and P = .796, respectively). This study showed that breakage of bioabsorbable cross-pins is a relatively common phenomenon. Broken cross-pins were a factor relating to laxity after ACL reconstructions with hamstring grafts. Posterior direction of the cross-pin may be a cause of pin breakage. Level IV, therapeutic case series.

A comparative study on the clinic effects of arthroscopic reconstructions of partial, single-bundle and double-bundle ACLs

Objective To discuss the clinic differences among arthroscopic reconstructions of partial, single-bundle and double-bundle ACLs after ACL injury of the knee. Methods A total of 56 cases of ACL arthroscopic reconstruction were involved in this study, including 11 partial reconstructions, 25 single-bundle ones and 20 double-bundle ones. The IKDC2000, Tegner and Lysholm evaluations were performed for every patient pre- and postoperatively. KT-2000 and Back Pushing KT-2000 measurements were also done. Paired t-test was used to analyze the IKDC, Tegner and Lysholm scores before operation and at follow-up time. Mann-Whitney was used to analyze KT-2000 results. Results Follow-up time averaged 19.84± 5.03 months （13 to 22 months） . Paired t-test showed the IKDC, Lysholm and Tegner scores were significantly improved after operation. Back Pushing KT-2000 Measurement showed double-bundle ACL reconstruction restored the knee stability better than single-bundle technique, and partial ACL reconstruction resulted in the best outcome among the 3 groups. Normal KT-2000 measurement failed to detect any significant difference among them. Conclusion Partial ACL reconstruction can restore the knee stability better than the double-bundle reconstruction, and the double-bundle ACL reconstruction better than the single-bundle one. Back Pushing KT-2000 Measurement may have important value in knee stability analysis for partial and double-bundle ACL reconstructions. Key words: Anterior cruciate ligament; Rupture; Reconstruction

Measurement of laxity in the anterior cruciate ligament-deficient knee: A comparison of three different methods in vitro

The aim of this study was to compare in-vitro measurements of anteroposterior laxity in the anterior cruciate ligament (ACL)-deficient knee using three different methods: an Instron materials-testing machine, then a KT-2000 arthrometer, and finally by Roentgen stereophotogrammetric analysis (RSA). Eight ACL-deficient human cadaver knees were used. Total displacement was measured between 90 N anterior and 90 N posterior tibiofemoral drawer forces at both 20 degrees and 90 degrees knee flexion. Laxity ranged from 11.5 to 27.6 mm at 20 degrees and from 8.7 to 23.9 mm at 90degrees. A statistically significant difference was not found between the mean RSA and KT-2000 measurements. However, the mean Instron measurements of laxity were significantly (3-4 mm) higher than both RSA and KT-2000 measurements. The clinical methods of RSA and the KT-2000 measurements agreed well but appeared to underestimate tibiofemoral anteroposterior laxity compared with the materials-testing machine. These findings may be helpful in the future comparison of different studies.

Fourteen-Year Prospective Results of a High-Density Polyethylene Prosthetic Anterior Cruciate Ligament Reconstruction

Our experience with an ultrahigh molecular weight polyethylene (UHMWPE) braided graft indicates that this prosthetic anterior cruciate ligament (ACL) is not associated with the complications of other prosthetic ligaments and has equivalent results compared to an autograft. Nine patients underwent ACL reconstruction with the UHMWPE prosthetic graft, and seven patients received a bone-patellar-bone autograft. Each patient completed a questionnaire regarding their symptoms, a Tegner score, and a Lysholm Score. Objective results included a physical examination and KT1000 measurement. Noninferiority statistical methods were utilized to calculate a power to detect a clinically relevant difference between the groups. Six individuals from the prosthetic group and six of the controls have been followed an average of 14.1 years. In the prosthetic group, one graft failed at 9.5 years after the reconstruction. There were no sterile effusions. There were no graft failures or sterile effusions in the controls. Tegner scores were equivalent (control = 5.5, prosthetic = 5.0) as were the Lysholm scores (control = 82, prosthetic = 80.5). KT1000 testing for the prosthetic group (mean side-to-side difference in maximal displacement = 1.75 mm) was not inferior to the control group (2.0 mm). In this prospective study with 14 years of follow-up, the subjective and objective results of a prosthetic ACL compares favorably to an autograft, suggesting reconsideration of a prosthetic graft options as a viable option.

Anterior Cruciate Ligament Tear: Reliability of MR Imaging to Predict Stability after Conservative Treatment

ObjectiveThe aim of this study is to evaluate the reliability of MR imaging to predict the stability of the torn anterior cruciate ligament (ACL) after complete recovery of the ligament's continuity.Materials and MethodsTwenty patients with 20 knee injuries (13 males and 7 females; age range, 20-54) were enrolled in the study. The inclusion criteria were a positive history of acute trauma, diagnosis of the ACL tear by both the physical examination and the MR imaging at the initial presentation, conservative treatment, complete recovery of the continuity of the ligament on the follow up (FU) MR images and availability of the KT-2000 measurements. Two radiologists, who worked in consensus, graded the MR findings with using a 3-point system for the signal intensity, sharpness, straightness and the thickness of the healed ligament. The insufficiency of ACL was categorized into three groups according to the KT-2000 measurements. The statistic correlations between the grades of the MR findings and the degrees of ACL insufficiency were analyzed using the Cochran-Mantel-Haenszel test (p < 0.05).ResultsThe p-values for each category of the MR findings according to the different groups of the KT-2000 measurements were 0.9180 for the MR signal intensity, 1.0000 for sharpness, 0.5038 for straightness and 0.2950 for thickness of the ACL. The MR findings were not significantly different between the different KT-2000 groups.ConclusionMR imaging itself is not a reliable examination to predict stability of the ACL rupture outcome, even when the MR images show an intact appearance of the ACL.

Single-and Double-incision Double-bundle ACL Reconstruction

Double-bundle anterior cruciate ligament (ACL) reconstruction is intended to replicate the anatomy and the function of the anteromedial and posterolateral bundles of the native ACL to improve patients' satisfaction and knee stability. We prospectively assigned 75 consecutive patients with an isolated ACL lesion to one of three sequential groups of 25 patients each. Group I received a single-bundle, single-incision transtibial ACL reconstruction. Groups II and III received a double-bundle reconstruction with a single-incision transtibial technique or a double-bundle, twoincision outside-in technique, respectively. We obtained subjective International Knee Documentation Committee and Knee Injury and Osteoarthritis Outcome Score evaluations and objective International Knee Documentation Committee scores and KT-1000 measurements preoperatively and at followup. All patients reached a minimum followup of 2 years. KT side-to-side difference in Groups I, II, and III were 2.4, 1.6 and 1.4 mm, respectively. Group III had fewer patients with a positive pivot shift than Group I. The double-bundle double-incision outside-in ACL reconstruction resulted in improved anteroposterior stability and less residual pivot shift than single-incision single-bundle technique.

A prospective comparison of bone-patellar tendon-bone and hamstring tendon grafts for anterior cruciate ligament reconstruction in male patients

The aim of the study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using central-third, bone-patellar tendon-bone (BPTB Group) (n = 45) and four-strand semitendinosus/gracilis (ST/G Group) (n = 78) autografts in male patients. The type of study is non-randomised, prospective consecutive series. A consecutive series of 126 male patients, all with unilateral ACL ruptures, was included in the study. In both groups, interference screw fixation of the graft was used at both ends and 123/126 (97%) of the patients returned for the follow-up examination after a period of 25 (23-33) months. The pre-operative assessments in both groups were similar in terms of the Tegner activity level, the Lysholm knee scoring scale, KT-1000 measurements, one-leg-hop test and knee-walking test. A significant reduction in knee laxity as measured with the KT-1000 arthrometer, compared with the pre-operative assessments, was found in both groups (P < 0.001). No significant differences in the post-operative knee-laxity measurements were found between the groups. Both groups had a significantly improved functional outcome at follow-up in terms of the Lysholm knee scoring scale, Tegner activity level and one-leg-hop test. The BPTB Group had a significantly higher Tegner activity level at follow-up, compared with the ST/G Group (P = 0.02). Moreover, the patients in the BPTB Group were significantly more likely to have a Tegner activity level of 6 or above (P = 0.03). Otherwise, no significant differences were found between the two study groups at the 2-year follow-up. Two years after an ACL reconstruction, the two groups displayed no significant differences in terms of functional outcome and knee laxity. However, more patients in the BPTB Group returned to a higher Tegner activity level than that in the ST/G Group.