Association between varus alignment and post-traumatic osteoarthritis after anterior cruciate ligament injury.

PURPOSE: To investigate the association between varus alignment and post-traumatic osteoarthritis (OA) after an anterior cruciate ligament (ACL) injury. METHODS: One hundred subjects with an acute complete ACL tear were followed for 15 years. Anterior-posterior radiographs of the tibiofemoral joint were obtained with a knee flexion of 20°, and the patellofemoral joint was examined with skyline view at 50° knee flexion. Joint space narrowing and osteophytes were graded in the tibiofemoral and patellofemoral joints in the injured (ACL) and uninjured knee according to the radiographic atlas of the Osteoarthritis Research Society International. The alignment of the uninjured, contralateral knee was measured at follow-up, using full-limb radiographs of leg with the knee in full extension. Alignment was expressed as the hip-knee-ankle (HKA) angle. Alignment was defined as valgus (HKA ≤178°), neutral (179°-181°) or varus (≥182°). RESULTS: Data from 68 subjects were included in the analysis. Varus alignment of the uninjured knee at follow-up appeared to be associated with OA of the injured knee 15 years after an ACL injury (odds ratio (95% confidence interval) 3.9 (1.0-15.8, p = 0.052)). CONCLUSIONS: Varus alignment of the uninjured knee at follow-up may be associated with OA of the injured knee 15 years after an ACL injury. LEVEL OF EVIDENCE: II.

Knee laxity after complete anterior cruciate ligament tear: a prospective study over 15 years.

There is limited knowledge of knee laxity in the long term after a complete anterior cruciate ligament (ACL) tear treated without ACL reconstruction. The aim of this study was (1) to describe the clinical course of knee laxity after a complete ACL tear over 15 years, and (2) to study the association between knee laxity and meniscal injuries and the development of knee osteoarthritis (OA). We studied 100 consecutive subjects [mean (SD) age 26 (8) years] presenting with acute ACL injury prospectively. The initial treatment in all subjects was knee rehabilitation without reconstructive surgery. The subjects were examined with Lachman's and pivot-shift tests at baseline, 6 weeks, 3 months, 1 year, 3 years and 15 years after the injury. Sagittal knee laxity was also evaluated with the KT-1000 arthrometer at the 15-year follow-up. During follow-up, 22 subjects were ACL reconstructed due to unacceptable knee instability. There was only a mild remaining knee laxity [median Lachman grade and pivot-shift test value of 1 on a 4-grade scale (0-3)] after 15 years in subjects treated without primary ACL reconstruction. Knees with higher anterior sagittal knee laxity 3 months after the injury had a worse long-term outcome with respect to meniscal injuries and knee OA development.

Patellofemoral osteoarthritis 15 years after anterior cruciate ligament injury--a prospective cohort study.

OBJECTIVE: Prevalence and clinical relevance of patellofemoral (PF) osteoarthritis (OA) after anterior cruciate ligament (ACL) injury. METHOD: Prospectively we studied 94 out of 100 consecutive patients 15 years after acute ACL injury. ACL reconstructions were only performed late if recurrent "give way" persisted or a secondary meniscal injury suitable for repair occurred. The subjects, mean age 42 years, had knee radiographs including skyline PF view taken, which were graded according to the atlas of the Osteoarthritis Research Society International. Knee-related symptoms and function were assessed by questionnaires. RESULTS: PF OA was present in 12/75 knees (16%). Of 94 patients 22 (23%) have had their ACL reconstructed during follow-up. Meniscal injury and ACL reconstruction had occurred more often in knees with PF OA than in knees without PF OA (P=0.004 and P=0.002, respectively). Seven of 15 ACL reconstructed knees showed radiographic PF OA at follow-up. Knees with PF OA had more extension and flexion deficit than knees without PF OA. Subjects with PF OA maintained a higher activity level from injury to follow-up, but did not differ significantly from those without PF OA regarding patient-relevant symptoms and knee function. However, there was a trend for worse outcome in subjects with PF OA. CONCLUSION: We found a relatively low prevalence of mild PF OA after ACL injury treated non-operatively, and it had limited impact on knee symptoms and patient-relevant knee function. At follow-up PF OA was associated with higher activity level, meniscal injury, extension and flexion deficit, and ACL reconstruction.

Proprioception after an acute knee ligament injury: a longitudinal study on 16 consecutive patients.

A defect in proprioception has been found in selected patient groups that have an anterior cruciate ligament deficient knee at different times after the original injury. The time of development and the extent of such defects were studied longitudinally on 16 consecutive patients. During the first year after a primary knee injury, which included a complete rupture of the anterior cruciate ligament, we repeatedly performed three tests of proprioception: (a) one to determine the threshold for detecting a passive motion from starting positions of 20 and 40 degrees, (b) an active reproduction of a passive angular change, and (c) a visual estimation of a passive angular change. The injured limb was compared with the uninjured limb and with the limbs of an age-matched reference group of healthy subjects. The population did not have a normal distribution, and some patients had consistently extreme recordings in the threshold tests at the various times of testing. Significant differences were found between the groups at the starting position of 20 degrees, when the injured knee was compared with the uninjured knee, after 1 month (p = 0.05), and after 2 months (p = 0.03). There was a trend toward a higher threshold for detecting a passive motion when the injured side was compared with the knees of the reference group at 1 month (p = 0.06) but not later on. A similar pattern was found for the injured knee at the starting position of 40 degrees, but it was not significant. An impaired ability to detect a passive motion was registered for the nearly extended knee 1 and 2 months after a primary injury. In the active reproduction and visual estimation tests, no significant defects were found at any time during the first year in these consecutively studied patients.

Bilateral proprioceptive defects in patients with a unilateral anterior cruciate ligament reconstruction: a comparison between patients and healthy individuals.

Proprioception of the knee was measured in 20 patients with reconstructed anterior cruciate ligaments and in 19 age-matched controls. The mean time from surgery was 2 years. Three tests of proprioception were used: (a) threshold to detection of passive motion from 20 and 40 degrees toward flexion and extension, (b) active reproduction of a 30 degrees passive angle change, and (c) visual reproduction of a 30 degrees passive angle change. The aim was a complete, bilateral, proprioceptive evaluation of patients who had undergone reconstruction of the anterior cruciate ligament. As compared with those in the control group, the knees with reconstructed anterior cruciate ligaments had a higher threshold to detection of passive motion in the extension trials from 20 and 40 degrees (p = 0.0003 and 0.04, respectively) and in the flexion trials from 20 and 40 degrees (p = 0.004 and 0.0008, respectively). When the uninjured knees of the patients were compared with those in the control group, higher values for threshold to detection of passive motion were found in the flexion trials from 20 degrees (p = 0.002) and 40 degrees (p = 0.02). Thus, decreased proprioceptive ability was present in some measurements of these patients after reconstructive surgery, not only in injured knees but also in uninjured knees, as compared with the reference group. The functional relevance of these findings was not investigated in this study, but the results suggest that bilateral proprioceptive considerations should be made when evaluating prognostic factors, treatment, and risk of contralateral knee injury in patients with reconstructed anterior cruciate ligaments.

Visual form integration and discontinuity detection.

Two experiments were conducted to determine if discontinuity detection limits the visual integration of two stimuli presented successively. If this is the case, then presenting two dim stimuli should permit better integration than presenting two bright stimuli. In Experiment 1, five observers named the position of the missing dot in a 5 x 5 dot matrix. Twelve randomly selected dots were presented in each of two stimulus presentations. The stimuli varied in intensity in a ratio of 15:1 and stimulus onset asynchrony (SOA) varied between 50 msec and 80 msec. At the longer SOAs, presenting two bright stimuli led to a higher percentage of correct responses than presenting two dim stimuli. There was no difference between those conditions at the shorter SOAs. In Experiment 2, 12 naive observers rated the amount of integration of the same stimuli on a 7-point scale, under the same presentation conditions. Rated integration was higher with two dim stimuli than with two bright stimuli. These apparently contradictory results are explained in terms of Hawkins and Shulman's distinction between two kinds of visual persistence. It is concluded that subjects can respond to integration and discontinuity detection separately. No evidence was found that discontinuity detection limits the integration.

Comparison of symptomatic versus nonsymptomatic patients with chronic anterior cruciate ligament insufficiency. Radiographic sagittal displacement during weightbearing.

The sagittal anterior displacement of the tibia, induced by weightbearing, in chronic anterior cruciate ligament-insufficient knees was measured radiographically in 2 groups of patients. All patients in both groups had an increased laxity when assessed with the Lachman and flexion-rotation-drawer test. Sixteen patients were functionally improved and were relatively asymptomatic after a neuromuscular rehabilitation program, while the second group consisted of another 16 patients with persistent functional instability, despite the same rehabilitation program, who eventually had ligament reconstruction. The mean radiographic anterior displacement during weightbearing in the nonsymptomatic group was 4.3 mm, and 8 patients had a displacement < or = 2 mm. In the symptomatic group, the corresponding value was 8.1 mm (P < 0.05), and 3 patients had a displacement < or = 2 mm. No correlations to meniscal injuries, age, or time from injury were found between the patients having a displacement >2 mm and those with < or = 2 mm. The findings should be explained by differences in neuromuscular control of the increased laxity in the injured knee.

A stabilometric technique for evaluation of lower limb instabilities.

Stabilometry is a technique designed to register postural equilibrium control. This investigation used a computerized strain gauge force plate to measure sway movements in the frontal plane with the patient standing on one leg. Fifty-five young healthy individuals were studied as a reference group and to determine the reproducibility of the method. The clinical population consisted of 14 patients with unilateral injuries to the lateral ligaments of the ankle. These were measured, both with and without an ankle brace. The different parameters used to describe the body sway could well discriminate between the injured and the uninjured leg. When the brace was used the effect was obvious and none of the parameters showed any significant difference compared to the uninjured leg.

The effect of physiotherapy on standing balance in chronic anterior cruciate ligament insufficiency.

Body sway movements in the frontal plane in a single-limbed stance test were used to assess postural control in 26 patients with chronic anterior cruciate ligament insufficiency. The injured and the noninjured legs were tested before the patients were committed to physiotherapy for 3 to 6 months. Follow-up tests were made after 3, 12, and 36 months. Significant disturbance of the balance of both legs was found before training, compared with a reference group of normal subjects. Values of the noninjured leg were normalized after 3 months of training, but the injured leg still showed an increased body sway. Normal balance parameters on the injured side were found at examination after 12 months. Follow-up examination after 36 months proved persistent normalization of the single-limbed balance on both sides.

Simultaneous measurements of sagittal knee laxity with an external device and radiostereometric analysis.

We obtained simultaneous measurements of sagittal knee laxity in 12 consecutive patients after reconstruction of the anterior cruciate ligament (ACL), using the Stryker laxity tester and radiostereometric analysis (RSA). The mean anteroposterior (AP) displacement when a 90 N load was applied in both directions was 5.3 +/- 2.7 mm with RSA and 9.8 +/- 1.6 mm with the external device (p < 0.001). The corresponding measurements at a load of 180 N were 5.7 +/- 2.4 mm and 13.8 +/- 3.7 mm, respectively (p < 0.001). More than 50% of the sagittal knee movement, as measured by the external device at a load of 180 N, was not true femorotibial displacement of the joint but was due to soft-tissue deformation.

Influence of supervised and nonsupervised training on postural control after an acute anterior cruciate ligament rupture: a three-year longitudinal prospective study.

STUDY DESIGN: Prospective randomized longitudinal clinical trial with matched controls. OBJECTIVES: To investigate the long-term effect of training on postural control and extremity function after an acute anterior cruciate ligament (ACL) injury. BACKGROUND: ACL injuries may cause severe problems with recurrent giving way of the knee and reduced functional capacity. The effect of an acute ACL injury and the effect of various training programs on postural control, as well as the relation between postural control and extremity function after such an injury, have not been studied longitudinally. METHODS: Sixty-three consecutive patients, 35 men and 28 women (median age 24 years, quartiles 19-33 years), with an acute nonoperated ACL injury, randomized to neuromuscular supervised or self-monitored training, were examined with stabilometry (amplitude and average speed of center of pressure movements) and a one-leg hop test for distance after 6 weeks (stabilometry only), and after 3, 12, and 36 months, and were compared to a control group. RESULTS: Regardless of treatment, center of pressure amplitude was persistently higher in both the injured and uninjured legs during the 3-year follow-up, but average speed was less affected or unaffected compared to the control group. The one-leg hop had normalized in the neuromuscular group at the 12-month follow-up, but was shorter in both legs throughout the 3-year period in the self-monitored group. The median value (quartiles) for injured/uninjured legs at 3 months was 150 cm (120-174 cm)/177 cm (140-199 cm), at 12 months was 174 cm (140-200 cm)/180 cm (150-202 cm), and at 36 months was 172 cm (146-200 cm)/178 cm (150-200 cm) in the self-monitored group, compared to the control group (median 186 cm, quartiles 177-216 cm). CONCLUSIONS: The higher center of pressure amplitude in both legs over the 3-year period indicate persistently impaired postural control in single-limb stance. However, functional performance, as measured with the one-leg hop test, was restored by neuromuscular training, but not by self-monitored training.

Review of knee proprioception and the relation to extremity function after an anterior cruciate ligament rupture.

Several tests of human conscious knee proprioception have been described, but there is no consensus or reference standard established. Difficulties remain in the separation of information originating from muscles, tendons, and joints, and the tests cannot discriminate between loss of afferent signals or altered activity in the remaining receptors. There is convincing evidence from several descriptive studies that the afferent information is altered after a knee ligament injury and severely disturbed in some patients with anterior cruciate ligament (ACL) injuries. However, an inherent inferior proprioceptive ability may also exist in some individuals, which makes them vulnerable to injuries. The deficits in proprioception have mostly been studied and related to the consciously registered sense, whereas the extent of possible disturbances of the unconscious or reflectory mechanisms is largely unknown. The latter may, at least from a theoretical point of view, be predominantly contributing to the overall afferent regulation, and a possibility for major defects thus exists, since there is no knowledge of the quantified relation between the conscious and unconscious part. The clinical importance of the altered afferent information has not been evaluated properly, and the role of proprioception that contributes to function has yet to be investigated. A higher physiological sensitivity to detecting a passive joint motion closer to full extension has been found both experimentally and clinically, which may protect the joint due to the close proximity to the limit of joint motion. Proprioception has been found to have a relation to subjective knee function, and patients with symptomatic ACL deficiency seem to have larger deficits than asymptomatic individuals. Little is known about whether training can restore defects in sensory information or by which mechanisms possible compensatory pathways are established. In rehabilitation, each patient must, however, create muscle strength, alertness, and stiffness in harmony with the disturbed mechanics of the knee, which are present both after nonoperative treatment of the ACL and after a reconstruction of the ACL.

Proprioception in people with anterior cruciate ligament-deficient knees: comparison of symptomatic and asymptomatic patients.

STUDY DESIGN: Nonrandomized prospective study. OBJECTIVE: To evaluate proprioception in 2 groups of patients with anterior cruciate ligament (ACL) deficiency who had different severity of symptoms. BACKGROUND: Defective proprioception has previously been found in patients with ACL-deficient knees. It has been suggested that sensory receptors of the ACL and other knee joint ligaments contribute to proprioception and knee joint function and stability. METHODS AND MEASURES: A total of 17 patients with ACL deficiency (mean [SD] age, 28.8 +/- 5.6 years; range, 22-39 years) with few, if any, symptoms were compared with 20 patients with ACL deficiency (mean [SD] age, 26.6 +/- 6.1 years; range, 18-39 years) having instability and episodes of giving way. The groups were compared with each other and with an age-matched reference group of 19 nonimpaired subjects. Their mean (SD) age was 25.6 +/- 3.7 years (range, 20-37 years). Three tests of proprioception were used: threshold to detection of passive motion from 2 starting positions (20 degrees and 40 degrees of knee flexion) toward flexion and extension, active reproduction of a 30 degrees passive angle change, and visual reproduction of a 30 degrees passive angle change. The Wilcoxon rank sum test was used for between-group comparisons. RESULTS: Symptomatic patients had higher threshold to detection of passive motion in their injured side in the flexion trial from 20 degrees (median of 1.5 degrees vs median of 0.5 degree) and in the extension trial from 40 degrees (median of 1.0 degree vs median of 0.5 degree) than the asymptomatic patients. No differences were found in the other threshold tests, active or visual reproduction tests. CONCLUSIONS: Patients with severe symptoms related to ACL deficiency were found to have inferior proprioceptive ability in some measurements compared with patients with a good knee function. The findings indicate that proprioceptive deficits might influence the outcome of an ACL injury treated nonoperatively.

Clinical measurements of proprioception, muscle strength and laxity in relation to function in the ACL-injured knee.

A knee injury with anterior cruciate ligament (ACL) rupture may cause deficits in proprioception, increased laxity and decreased muscle strength. Although it may be common knowledge that these factors affect knee function, only a few studies have been performed where this has been investigated in the clinical situation, and the results are not conclusive. The purpose of this study was therefore to investigate how and to what extent proprioception, laxity and strength affect knee joint function and evaluate if the methods commonly used for estimating these factors clinically seem to be relevant. The study encompassed 36 patients with ACL deficiency. A single-leg hop test for distance and subjective rating of knee function were defined as dependent variables and analyzed separately in stepwise linear regression models where proprioception, knee joint laxity, hamstrings and quadriceps strength, age and sex were defined as independent variables. Higher threshold values (poorer proprioception), increased side-to-side difference of anterior laxity and poorer strength significantly predicted shorter length of the hop test. Higher rating of subjective function corresponded to female gender, lesser side-to-side difference of anterior laxity and better proprioception.

A case of superior dislocation of the patella.

A 56-year-old woman with arthrosis of the knee sustained a fixed superior dislocation of the patella from a minor trauma. Closed reduction was performed. Only 3 other cases have been found reported in the literature.

Lesion of the anterior cruciate ligament and sagittal disalignment of the knee in weight-bearing.

Twenty-nine patients with late reconstructive surgery for anterior cruciate ligament lesions had a clinical and radiologic follow-up ten years after injury. Anterior sagittal displacement of the tibia was recorded on the routine standing radiographs in 16 knees all having a normal femoro-tibial alignment in the non-weight-bearing position. Five of eleven patients with sagittal displacement of between 10 and 19 mm had early osteoarthrosis, which was confirmed by magnetic resonance imaging in four cases; their ages ranged from 23 to 38 years. No radiographic signs of osteoarthrosis were observed in those with displacements of less than 10 mm. In some patients there was a discrepancy between the clinical and radiographic measurements of instability. In addition to the clinical tests of instability standing rather than non-weight-bearing lateral radiographs are suggested for the routine assessment of cruciate ligament injuries.

Severe aseptic synovitis of the knee after biodegradable internal fixation. A case report.

Biodegradable rods made of polyglycolide (Dexon, Biofix) or lactide-glycolide copolymer (Vicryl) have been used for the past 5 years for internal fixation of a variety of fractures and osteotomies (Böstman et al. 1989, 1990b). Experience from using such rods for fixation of intraarticular osteochondral lesions seems to be less extensive. We report a case of severe synovial reaction to biodegradable rods used for fixation of osteochondritis dissecans of the knee and discuss possible reasons for the increased risk of foreign-body reactions when these rods are used intraarticularly.

Laxity and graft fixation after reconstruction of the anterior cruciate ligament. A roentgen stereophotogrammetric analysis of 11 patients.

The sagittal laxity of the knee was measured in 11 consecutive patients with chronic anterior cruciate ligament deficiency before and 1 year after ligament reconstruction with a free bone-tendon-bone graft from the patellar tendon (modified Clancy technique). Tantalum markers were implanted in the femur, in the tibia, and in the graft for roentgen stereophotogrammetric analysis (RSA) of the sagittal laxity and the migration of the bony ends of the graft. The precision in measurements of total anterior-posterior displacement (+/- 2 SD of the differences between repeated measurements) was 2.2 mm. A decrease in total anterior-posterior displacement from 12 mm before reconstruction of 5 mm 1 year postoperatively using a stress load of 150 N was found. The bony ends of the free graft migrated maximally 0.7 mm, implying adequate fixation.

Persistent stability 3 years after reconstruction of the anterior cruciate ligament. A radiostereometric analysis (RSA) of 20 patients.

We measured, by radiostereometric analysis (RSA), the sagittal knee laxity in 20 consecutive patients with chronic anterior cruciate ligament injuries before, 1 year and 3 years after reconstruction with a free bone-patellar tendon-bone graft. The grafts had been perioperatively tensioned, using a 10-15 N load. An increased displacement with increasing load was present before reconstruction, but we found no differences between 100 and 150 N stress load 1 and 3 years after the operation. The total anteroposterior displacement decreased from 12.7 mm before the reconstruction to 5.1 mm 1 year and 5.6 mm 3 years postoperatively, using a stress load of 150 N. Thus, we found both a definite end-point of joint displacement and persistent stability without elongation of the graft with time, when care was taken not to over-constrain the knee by a high initial graft tension.

Muscle training in chronic anterior cruciate ligament insufficiency--a comparative study.

The aim of the investigation was to study and compare the effect of two basically different training methods on muscle strength and knee function on a consecutive and prospective series of 26 conservatively treated patients with chronic anterior cruciate ligament injury. The two training models were: model Q directed towards specific training of knee extensor muscle strength and model F aiming at training of the lower extremity and trunk muscles in functional weightbearing patterns. The parameters evaluated were: isometric and isokinetic muscle strength, a performance test (one-leg hop test), and a functional score. The results after a three-month training period showed in both groups a significant increase of muscle strength in both knee extensors and knee flexors. No significant difference of isokinetic strength values between the two groups was observed. The isometric gain of knee extension was significantly higher in the Q group. The one-leg hop test value and the functional score were also significantly increased in both groups. However, the hop test indicated a more favourable result in the group who were trained functionally.