Impact of type of meniscal tear on radiographic and symptomatic knee osteoarthritis: a sixteen-year followup of meniscectomy with matched controls

Does operative fixation of an osteochondritis dissecans loose body result in healing and long-term maintenance of knee function?

BACKGROUND

Osteochondritis dissecans (OCD) can progress to loose body formation, resulting in a grade IV defect. The decision to fix versus excise the loose body is controversial. Published operative fixation outcomes are small case series with short follow-up.

HYPOTHESIS

Operative fixation (ORIF) of the loose body into the grade IV defect will heal and approximate "normal" knee function at long-term follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twelve patients were identified who underwent ORIF of a knee OCD loose body into the grade IV osteochondral defects ranging in size from 2.0 to 8.0 cm(2) (mean, 3.5 cm(2)). After 12 weeks, hardware was removed, and healing was assessed. Long-term outcomes were assessed with a Knee injury and Osteoarthritis Outcome Score (KOOS) and a Marx activity score.

RESULTS

Arthroscopy for screw removal revealed stable healing in 92% (11 of 12) of patients. No patients required subsequent surgery for a loose body. At an average of 9.2 years' follow-up (range, 3.8-15.8 years), 83% (10 of 12) of patients completed the KOOS. The KOOS subscale scores for pain (mean, 87.8; range, 67-100), other symptoms (mean, 81.8; range, 61-96), function in activities of daily living (mean, 93.1; range, 72-100), and sports and recreation function (mean, 74.0; range, 40-100) were not significantly lower than those of published age-matched controls. However the KOOS subscale score for knee-related quality of life (mean, 61.9; range, 31-88) was significantly lower (P = .003).

CONCLUSION

Operative fixation of grade IV OCD loose bodies results in stable fixation. At an average 9 years after surgery, patients did not have symptoms of osteoarthritis pain and had normal function in activities of daily life. However, patients reported significantly lower knee-related quality of life. Operative fixation of OCD loose bodies is a better alternative to lesion excision.

Multiple ligament knee reconstruction clinical follow-up and gait analysis

Multiple ligament knee injuries are serious and rare injures that have not been studied using advanced gait analysis techniques. The purpose of this study was to perform clinical follow-up and gait analysis on patients with multiple knee ligament reconstruction. Twenty-four patients who underwent a multi-ligament knee reconstruction by a single surgeon volunteered to participate in this study. We performed complete clinical exam including instrumented ACL exam (KT-1000), and radiological exam including weight-bearing and PCL stress radiographs (TELOS) at minimum 2 years post index surgery. In addition, we performed complete three-dimensional gait analysis on 18 patients. We used a 10-camera, high speed (120 Hz) motion analysis system in conjunction with a multi-axis strain-gage force plate which calculated knee joint kinetics and kinematics while subjects performed flat-ground walking and stair-descent tasks. Kinematic and kinetic variables were compared between reconstructed and contralateral knees and unmatched, healthy control knees. All knee joint moments were normalized to subjects' weight. Clinical: Average knee joint flexion/extension 123.6 +/- 15.5/1.7 +/- 3.5, respectively. Average KT-1000 side-to-side difference was 1.2 +/- 2.0 mm, TELOS side-to-side difference on stress radiographs was 4.0 +/- 3.1 mm. Median IKDC score was 67 (range 13-94). Fifty-three percent of patients exhibited radiographic evidence of osteoarthritis (OA) on the operative side; one patient on the contralateral knee. During gait analysis, patients exhibited significantly reduced total knee joint range of motion, and external knee flexion moment in the reconstructed knee compared to the contralateral knee and healthy control knees. The magnitude of these differences was greater while descending a step. Finally, patients who had radiographic evidence of knee joint OA had significantly lower magnitude external knee flexion moment compared to those who did not have OA at the time of follow-up. Greater than 2 years after reconstruction, patients with multi-ligament knee injuries are able to return to daily activities. Gait analysis data suggests that patients may be experiencing higher magnitude changes in sagittal plane kinematics and kinetics during demanding functional tasks (stair decent). Changes in walking gait biomechanics may help explain why this group is experiencing unilateral knee joint degeneration.

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.

The measurement of joint mechanics and their role in osteoarthritis genesis and progression

Mechanics play a role in the initiation, progression, and successful treatment of osteoarthritis. However, we don't yet know enough about which specific mechanical parameters are most important and what their impact is on the disease process to make comprehensive statements about how mechanics should be modified to prevent, slow, or arrest the disease process. The objectives of this review are (1) to summarize methods for assessing joint mechanics and their relative merits and limitations, (2) to describe current evidence for the role of mechanics in osteoarthritis initiation and progression, and (3) to describe some current treatment approaches that focus on modifying joint mechanics.

How close are we to having structure-modifying drugs available?

This review describes the potential of disease-modifying osteoarthritis drugs (DMOADs), distinguishing between preventing, retarding, stopping, and reversing disease and what might be clinically meaningful. The authors also describe whether there is any evidence to suggest that one can modify disease, and whether the current tissue that is predominantly focused on, namely, cartilage, is an appropriate target. The methodologic approaches and other obstacles to demonstrating efficacy of these agents in clinical trials are considered. This discussion is a narrative review in a field that is rapidly evolving. It is hoped the reader appreciates the complexity of the field and the likely road ahead to DMOAD development.

Knee injury outcomes measures

Outcomes measures have long been used in the assessment of knee injuries and management protocols. In the past decade, there has been a shift from clinician-based outcomes tools to the development and validation of patient-reported outcomes measures. General health as well as disease- and medical condition-specific outcomes measures have been so modified. The Medical Outcomes Study 36-Item Short Form is the most commonly used general health measure in orthopaedics. Joint-specific measures include the Western Ontario and McMaster Universities Osteoarthritis Index, the Knee Injury and Osteoarthritis Outcome Score, and the International Knee Documentation Committee Subjective Form. The Lysholm Knee Scale and the Cincinnati Knee Rating Scale continue to be popular, especially for the assessment of ligamentous injuries. The ACL Quality of Life score is a disease-specific, patient-reported outcomes measure of anterior cruciate ligament deficiency. The historically used Tegner activity level scale and the recently developed Marx activity level scale are used in conjunction with these outcomes measures to make possible a global assessment of recovery from knee injuries and clinician interventions.

Tibio-femoral cartilage defects 3-5 years following arthroscopic partial medial meniscectomy

OBJECTIVE

Arthroscopic partial medial meniscectomy (APMM) is a common procedure to treat a medial meniscal tear. Individuals who undergo APMM have a heightened risk of developing tibio-femoral osteoarthritis (OA). Cartilage defects scored from magnetic resonance imaging (MRI) scans predict cartilage loss over time. It is not known whether cartilage defects in the early years following APMM are more common or of greater severity than in age-matched controls. This study compared the prevalence and severity of tibio-femoral cartilage defects in patients 3-5 years post-APMM with that of age-matched controls.

METHODS

Twenty-five individuals who had undergone APMM in the previous 46.9+/-5.0 months and 24 age-matched controls participated in this study. Sagittal plane knee MRI scans were acquired from the operated knees of patients and from randomly assigned knees of the controls and graded (0-4) for tibio-femoral cartilage defects. Defect prevalence (score of >or=2 for any compartment) and severity of the cartilage from both tibio-femoral compartments were compared between the groups.

RESULTS

The APMM group had greater prevalence (77 vs 42%, P=0.012) and severity (4.1+/-1.9 vs 2.8+/-1.1, P=0.005) of tibio-femoral cartilage defects than controls. Age was positively associated with tibio-femoral cartilage defect severity for APMM, r=0.523, P=0.007, but not for controls, r=0.045, P=0.834.

CONCLUSION

Tibio-femoral joint cartilage defects are more prevalent and of greater severity in individuals who had undergone APMM approximately 44 months earlier than in age-matched controls.

Changes in gait after bilateral meniscectomy in sheep: effect of two hyaluronan preparations

BACKGROUND

This study examined the effect of bilateral meniscectomy on ground reaction forces (GRFs) in sheep, and the therapeutic effect of two hyaluronan (HA) preparations.

METHODS

Eighteen sheep were subjected to bilateral lateral meniscectomy and were treated from 16 to 20 weeks postoperatively with intraarticular Hyalgan (Fidia Farmaceutici), HYADD4-G (a novel amide derivative; Fidia Farmaceutici), or saline placebo (n = 6 per group). GRFs were assessed at baseline and 6, 12, 16, 22, and 26 weeks postoperatively. Rheological parameters and HA content of synovial fluid samples were assessed using micro-Fourier rheometry.

RESULTS

Meniscectomy significantly reduced GRF and abolished the normal two-peak vector. GRF deficits were partially ameliorated by both HA preparations: Hyalgan increased peak vertical forces at 6 weeks post-treatment (week 22), while HYADD4-G increased vertical impulse post-treatment. Both HA treatments, but not saline placebo, restored a twopeak composite force vector at 6 weeks post-treatment. Neither HA preparation significantly modulated osteoarthritis (OA) severity, or synovial fluid parameters.

CONCLUSIONS

This study showed that GRF responses to bilateral meniscectomy in sheep mimic available data for human meniscectomy and OA patients. However, this time course suggests that gait deficits are temporally unrelated to observed cartilage or synovial fluid changes. The bilateral ovine meniscectomy model demonstrates modest but quantifiable changes in GRF that mimic human OA and are amenable to modification by known OA therapies such as HA.

How close are we to having structure-modifying drugs available?

This article describes what structure modification is, explains the distinctions among preventing, retarding, stopping, and reversing disease, and suggests approaches that might be clinically meaningful. It discusses whether any evidence suggests it is possible to modify disease and whether the current focus on cartilage is appropriate. It considers the methodologic approaches and the obstacles to demonstrating efficacy of these agents in clinical trials. The authors hope that at the end of this narrative review the reader will appreciate the complexities of this rapidly evolving field and of the development of disease-modifying drugs for osteoarthritis drugs.

Relevant traumatic injury of the knee joint-MRI follow-up after 7-10 years

OBJECTIVE

To evaluate prospectively the history of relevant traumatic knee injuries at least 7 years after trauma by MRI focusing on the development of degenerative changes.

MATERIALS AND METHODS

Seventeen patients without baseline degenerative changes had a follow-up knee MRI several years after relevant knee injury (interval baseline-follow-up was 9.1 years, S.D. +/-1.3 years). Relevant knee injury was defined as complete cruciate or collateral ligament rupture, traumatic meniscal tear or osteochondral injury. Baseline MRI examinations were evaluated for traumatic ligamentous, chondral, meniscal and osseous lesions. Follow-up MRIs were evaluated for ligamentous and meniscal status, articular surface and incidence of degenerative changes such as cartilage loss, osteophytes and bone marrow lesions.

RESULTS

Among the 11 patients who had a complete rupture of the ACL at baseline, 3 (27.3%) presented with cartilage loss. Among the eight patients who had suffered a post-traumatic meniscal tear at baseline, four (50%) presented with cartilage loss at follow-up. Among the five patients who had an osteochondral fracture at baseline, two (40%) presented with cartilage loss at follow-up imaging. Cartilage loss in all cases was observed adjacent to the subregions where meniscal damage and/or osteochondral incongruence was/were present at follow-up imaging.

CONCLUSION

We hypothesize that the post-traumatic or postsurgical meniscal damage and the persistence of an irregular articular surface may have played a role in the subsequent loss of cartilage in our patient population.

Incidental meniscal findings on knee MRI in middle-aged and elderly persons

BACKGROUND

Magnetic resonance imaging (MRI) of the knee is often performed in patients who have knee symptoms of unclear cause. When meniscal tears are found, it is commonly assumed that the symptoms are attributable to them. However, there is a paucity of data regarding the prevalence of meniscal damage in the general population and the association of meniscal tears with knee symptoms and with radiographic evidence of osteoarthritis.

METHODS

We studied persons from Framingham, Massachusetts, who were drawn from census-tract data and random-digit telephone dialing. Subjects were 50 to 90 years of age and ambulatory; selection was not made on the basis of knee or other joint problems. We assessed the integrity of the menisci in the right knee on 1.5-tesla MRI scans obtained from 991 subjects (57% of whom were women). Symptoms involving the right knee were evaluated by questionnaire.

RESULTS

The prevalence of a meniscal tear or of meniscal destruction in the right knee as detected on MRI ranged from 19% (95% confidence interval [CI], 15 to 24) among women 50 to 59 years of age to 56% (95% CI, 46 to 66) among men 70 to 90 years of age; prevalences were not materially lower when subjects who had had previous knee surgery were excluded. Among persons with radiographic evidence of osteoarthritis (Kellgren-Lawrence grade 2 or higher, on a scale of 0 to 4, with higher numbers indicating more definite signs of osteoarthritis), the prevalence of a meniscal tear was 63% among those with knee pain, aching, or stiffness on most days and 60% among those without these symptoms. The corresponding prevalences among persons without radiographic evidence of osteoarthritis were 32% and 23%. Sixty-one percent of the subjects who had meniscal tears in their knees had not had any pain, aching, or stiffness during the previous month.

CONCLUSIONS

Incidental meniscal findings on MRI of the knee are common in the general population and increase with increasing age.

Prevalence of tibiofemoral osteoarthritis 15 years after nonoperative treatment of anterior cruciate ligament injury: a prospective cohort study

BACKGROUND

The occurrence of osteoarthritis (OA), associated meniscal injuries, meniscectomy, and patient-related measures for patients treated nonoperatively after anterior cruciate ligament (ACL) injuries have not been well described in the literature in terms of natural history.

HYPOTHESIS

Patients with ACL injury can achieve a low occurrence of tibiofemoral OA and good knee function when treated without ACL reconstruction.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

One hundred consecutive patients with an acute, complete ACL injury were observed for 15 years. All patients were primarily treated with activity modification and without ACL reconstruction. To achieve improved functional stability, supervised physical therapy was initiated early after injury. The patients were examined using anteroposterior weightbearing radiography. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used to quantify knee-related symptoms and knee function.

RESULTS

Seventy-nine patients consented to radiographic examination and 93 completed the KOOS questionnaire. Thirteen patients (16%), all of whom were among the 35 patients whose knees were meniscectomized, developed radiographic tibiofemoral OA. In contrast, none of the remaining nonmeniscectomized and radiographed knees developed OA (n = 44) (P < .0001). Sixty-three patients (68%) had an asymptomatic knee. Twenty-two patients (23%) had undergone ACL reconstruction with a mean time of 4 years after injury.

CONCLUSION

The study had a favorable long-term outcome regarding incidence of radiographic knee OA, knee function and symptoms, and need for ACL reconstruction. Although risk factors for posttraumatic OA are multifactorial, the primary risk factor that stood out in this study was if a meniscectomy had been performed. Early activity modification and neuromuscular knee rehabilitation might also have been related to the low prevalence of radiographic knee OA. In patients with ACL injury willing to moderate activity level to avoid reinjury, initial treatment without ACL reconstruction should be considered.

Association between findings on delayed gadolinium-enhanced magnetic resonance imaging of cartilage and future knee osteoarthritis

OBJECTIVE

To examine the predictive value of the delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) index with regard to future radiographic osteoarthritis (OA).

METHODS

In 1998, 17 knees in 11 men and 4 women with knee pain, normal results of weight-bearing radiography, and arthroscopic cartilage changes ranging from superficial fibrillation to fissuring and softening were examined using dGEMRIC. Six years later, 16 of the 17 knees were reassessed for radiographic OA changes.

RESULTS

At followup, 9 of the 16 knees showed radiographic OA changes. Two of them had undergone a knee joint replacement due to OA. In the knees with radiographic OA, the dGEMRIC index at baseline was lower than that in the knees without radiographic OA (P = 0.03).

CONCLUSION

The results of the present study support the dGEMRIC index as a clinically relevant measure of cartilage integrity and suggest that a low index may be predictive of the development of knee OA.

Predictors of short-term recovery differ from those of long-term outcome after arthroscopic partial meniscectomy

PURPOSE

The purpose of this study was to determine which patient clinical and demographic factors are associated with the short-term rate of recovery from arthroscopic partial meniscectomy in the year after surgery and how they differ from previously published associations with long-term outcome.

METHODS

Depth of meniscal excision, involvement of 1 or both menisci, extent of meniscal tear, and extent of osteoarthritis were determined during surgery, and age, body mass index, and gender were recorded. Mixed-model repeated-measures analyses were used longitudinally to identify independent predictors of recovery, measured by prospectively assessing knee pain, knee function, and overall physical knee status preoperatively and at regular intervals throughout postoperative recovery.

RESULTS

Neither advanced age nor increased body mass index had any influence on patient recovery over time, whereas gender was implicated, with women having significantly poorer recovery scores than men (P < .04). In addition, differences in variables indicating extent of meniscal tear and resection did not influence recovery scores over time, and the only surgical factor that impacted all 3 recovery variables was extent of osteoarthritis (P < .02).

CONCLUSIONS

We have shown that female gender and worse osteoarthritis are associated with a slower rate of short-term recovery from arthroscopic partial meniscectomy whereas age, obesity, and amount of meniscal tear/resection showed no association with rate of recovery throughout the first year postoperatively.

LEVEL OF EVIDENCE

Level I, high-quality prognostic prospective study (all patients were enrolled at the same point in their disease with more than 80% follow-up of enrolled patients).

Association between meniscal tears and the peak external knee adduction moment and foot rotation during level walking in postmenopausal women without knee osteoarthritis: a cross-sectional study

INTRODUCTION

Meniscal injury is a risk factor for the development and progression of knee osteoarthritis, yet little is known about risk factors for meniscal pathology. Joint loading mediated via gait parameters may be associated with meniscal tears, and determining whether such an association exists was the aim of this study.

METHODS

Three-dimensional Vicon gait analyses were performed on the dominant knee of 20 non-osteoarthritic women, and the peak external knee adduction moment during early and late stance was determined. The degree of foot rotation was also examined when the knee adductor moment peaked during early and late stance. Magnetic resonance imaging was used to determine the presence and severity of meniscal lesions in the dominant knee.

RESULTS

The presence (P = 0.04) and severity (P = 0.01) of medial meniscal tears were positively associated with the peak external knee adduction moment during early stance while a trend for late stance was observed (P = 0.07). They were also associated with increasing degrees of internal foot rotation during late stance, independent of the magnitude of the peak external knee adduction moment occurring at that time (P = 0.03). During level walking among healthy women, the presence and severity of medial meniscal tears were positively associated with the peak external knee adduction moment. Moreover, the magnitude of internal foot rotation was associated with the presence and severity of medial meniscal lesions, independent of the peak knee adductor moment during late stance.

CONCLUSION

These data may suggest that gait parameters may be associated with meniscal damage, although longitudinal studies will be required to clarify whether gait abnormalities predate meniscal lesions, or vice versa, and therefore whether modification of gait patterns may be helpful.

Knee joint ultrasonography of the ACLT rabbit experimental model of osteoarthritis: relevance and effectiveness in detecting meniscal lesions

OBJECTIVES

To develop a protocol for rabbit knee joint ultrasonography (US); to grade ultrasonographically the meniscal injuries of the anterior cruciate ligament transection (ACLT) rabbit model of osteoarthritis (OA); to assess with US the effectiveness of the ACLT; to compare final US with macroscopy for the evaluation of medial and lateral meniscal injuries depending on the age and weight when ACLT is performed.

METHODS

Twenty-two skeletally mature and adolescent New Zealand white rabbits were housed during the same period at the Institut Claude-Bourgelat, Lyon, France. Surgical ACLT was performed in the left knee of nine adolescent and five adult rabbits. Final US and macroscopic semi-quantitative grading of the meniscal injuries were compared 5 months after ACLT.

RESULTS

A standardised protocol was developed to evaluate the rabbit knee joint. US was performed in both control and ACLT knees. Normal and abnormal meniscal US appearances were described. A semi-quantitative scale to grade US meniscal injuries was created. Macroscopic and US total meniscal scores were significantly positively correlated (P<0.001, r=0.70). US detection of meniscal injuries was 92% sensitive and 87.5% specific compared to macroscopy. Positive and negative predictive values of US were, respectively, 92% and 87.5%. US detection of the ACLT effectiveness was 100% specific and 78.5% sensitive.

CONCLUSION

A significant relationship was found between ultrasonographic and macroscopic grading of meniscal injuries. US was both specific and sensitive in detecting meniscal lesions. We propose US as a non-invasive, non-expensive, in vivo imaging technique for preclinical studies in the ACLT rabbit OA model.

Change in self-reported outcomes and objective physical function over 7 years in middle-aged subjects with or at high risk of knee osteoarthritis

OBJECTIVE

In the present work, we describe the clinical course and predictors of change in self-reported outcomes and objectively assessed physical function over time in middle-aged subjects at high risk of, or with knee osteoarthritis (OA).

METHODS

We examined 259 subjects (mean (SD) age 52.6 (10.4)) at mean 18 and 25 years after previous meniscectomy and 50 population-based age- and sex-matched reference subjects with the Knee injury and Osteoarthritis Outcome Score (KOOS), one-leg hop for distance and number of knee-bendings in 30 s. Radiographic OA was defined as equivalent to Kellgren and Lawrence grade 2 or worse.

RESULTS

At first assessment, meniscectomised subjects reported worse pain, function and quality of life compared with the reference group (p<0.001). They also performed fewer knee-bendings per 30 s (27 vs 31, p = 0.02). The meniscectomised patients worsened over the 4-10-year observation time in all measured outcomes (p<0.001), and to a greater extent than the reference group in pain (-5, 95% CI -10 to 0) and one-leg hop (-11, 95% CI -18 to -3). Being a woman, or having radiographic knee OA, enhanced the worsening in self-reported and objectively assessed outcomes. Older age and a higher body mass index (BMI) influenced objectively assessed physical function, but not self-reported outcomes.

CONCLUSION

Worsening over time in knee-related pain and function is greater in meniscectomised subjects compared with reference subjects. Rehabilitative efforts may be warranted in middle-aged meniscectomised patients, especially in women and those who have developed radiographic knee OA, who are at greater risk of worsening.

Meniscal tear and increased tibial plateau bone area in healthy post-menopausal women

OBJECTIVE

Meniscal tears detected using magnetic resonance imaging (MRI) have been identified as a risk factor for the development and progression of Osteoarthritis, however the prevalence and significance of meniscal tears in healthy, asymptomatic adults remains to be studied. We investigated the prevalence of meniscal tears in a healthy pain free population of post-menopausal women and whether meniscal tears in this population are associated with changes in cartilage volume and defects and tibial plateau bone area over 2 years.

METHODS

Fifty-seven post-menopausal women underwent MRI of their dominant knee at baseline line and approximately 2 years later to assess meniscal tears, cartilage volume, cartilage defects and tibial plateau bone area.

RESULTS

Forty-six percent of women had a meniscal tear in either the medial and/or lateral compartment. Women who had a tear were older (P=0.01) and had more lateral cartilage defects (P=0.02). Medial meniscal tear was associated with 103 mm(2) greater tibial plateau bone area within the medial [95% confidence of interval (CI) 6.2, 200.3; P=0.04] and a lateral meniscal tear with a 120 mm(2) greater area within the lateral compartment (95% CI 45.5, 195.2; P=0.002).

CONCLUSION

This study demonstrates that meniscal tears are common in asymptomatic post-menopausal women and that they become more common with age. Meniscal tears were also associated with greater tibial plateau bone area but not cartilage volume, providing support to the hypothesis that tibial plateau bone changes occur before significant pathological changes in cartilage. Whether increased tibial plateau bone area predisposes to an increased risk of degenerative meniscal tears or whether it is a consequence of altered biomechanical forces in relation to meniscal tear will need to be determined.

Meniscal damage associated with increased local subchondral bone mineral density: a Framingham study

OBJECTIVE

Because menisci and the medial vs lateral tibial plateau bone mineral density ratio (M:L BMD) are associated with loading within the knee, we postulated there to be an association between compartment-specific meniscal damage and M:L BMD. We hypothesized that knees with higher M:L BMD, consistent with increased medial subchondral BMD, would be associated with medial meniscal damage, and lower ratios with lateral meniscal damage.

METHODS

We conducted a cross-sectional study evaluating participants in the Framingham Osteoarthritis Cohort having magnetic resonance images (MRIs), BMDs, and x-rays of the knee. Medial and lateral meniscal damage were defined on MRI. We performed a logistic regression with medial meniscal damage as the outcome testing M:L BMD groups as predictor variables. We adjusted for age and sex; we used generalized estimating equations (GEE) to adjust for correlation between knees. Identical analyses were performed evaluating lateral meniscal damage.

RESULTS

When evaluating the relation of M:L BMD to medial meniscal damage, the odds ratios (ORs) of prevalent medial meniscal damage from lowest to highest quartile of M:L BMD were 1.0 (referent), 1.9, 2.4 and 8.9, P for trend <0.0001. When evaluating the relation of M:L BMD to lateral meniscal damage, the ORs of prevalent lateral meniscal damage from lowest to highest quartile of M:L BMD were 1.0 (referent), 0.3, 0.2, and 0.2, P for trend = 0.001.

CONCLUSIONS

Meniscal damage is associated with higher regional tibial BMD in the same compartment. Our findings highlight the close relationship between meniscal integrity and regional tibial subchondral BMD.

Diagnostic value of history-taking and physical examination for assessing meniscal tears of the knee in general practice

OBJECTIVE

To assess the diagnostic value of history-taking and physical examination of meniscal tears in general practice.

DESIGN

An observational study determining diagnostic values (sensitivity, specificity, predictive value, and likelihood ratios).

SETTING

General practice.

PATIENTS

Consecutive patients aged 18 to 65 years with a traumatic knee injury who consulted their general practitioner within 5 weeks after trauma.

ASSESSMENT

Participating patients filled out a questionnaire (history-taking) followed by a standardized physical examination.

MAIN OUTCOME

Assessment of meniscal tears was determined by means of magnetic resonance imaging (MRI) and was performed blinded for the results of physical examination and history-taking.

RESULTS

Of the 134 patients included in this study, 47 had a meniscal tear. From history-taking, the determinants "age over 40 years," "continuation of activity impossible," and "weight-bearing during trauma" indicated an association with a meniscal tear after multivariate logistic regression analysis, whereas from physical examination only "pain at passive flexion" indicated an association. These associated determinants from history-taking showed some diagnostic value; the positive likelihood ratio (LR+) reached up to 2.0 for age over 40 years, whereas the isolated test pain at passive flexion from physical examination has less diagnostic value, with an LR+ of 1.3. Combining determinants from history-taking and physical examination improved the diagnostic value with a maximum LR+ of 5.8; however, this combination only applied to a limited number of patients.

CONCLUSION

History-taking has some diagnostic value, whereas physical examination did not add any diagnostic value for detecting meniscal tears in general practice.

Age-related changes in strength, joint laxity, and walking patterns: are they related to knee osteoarthritis?

BACKGROUND AND PURPOSE

Aging is associated with musculoskeletal changes and altered walking patterns. These changes are common in people with knee osteoarthritis (OA) and may precipitate the development of OA. We examined age-related changes in musculoskeletal structures and walking patterns to better understand the relationship between aging and knee OA.

METHODS

Forty-four individuals without OA (15 younger, 15 middle-aged, 14 older adults) and 15 individuals with medial knee OA participated. Knee laxity, quadriceps femoris muscle strength (force-generating capacity), and gait were assessed.

RESULTS

Medial laxity was greater in the OA group, but there were no differences between the middle-aged and older control groups. Quadriceps femoris strength was less in the older control group and in the OA group. During the stance phase of walking, the OA group demonstrated less knee flexion and greater knee adduction, but there were no differences in knee motion among the control groups. During walking, the older control group exhibited greater quadriceps femoris muscle activity and the OA group used greater muscle co-contraction.

DISCUSSION AND CONCLUSION

Although weaker, the older control group did not use truncated motion or higher co-contraction. The maintenance of movement patterns that were similar to the subjects in the young control group may have helped to prevent development of knee OA. Further investigation is warranted regarding age-related musculoskeletal changes and their influence on the development of knee OA.

The long-term consequence of anterior cruciate ligament and meniscus injuries: osteoarthritis

The objectives of this study are to review the long-term consequences of injuries to the anterior cruciate ligament and menisci, the pathogenic mechanisms, and the causes of the considerable variability in outcome. Injuries of the anterior cruciate ligament and menisci are common in both athletes and the general population. At 10 to 20 years after the diagnosis, on average, 50% of those with a diagnosed anterior cruciate ligament or meniscus tear have osteoarthritis with associated pain and functional impairment: the young patient with an old knee. These individuals make up a substantial proportion of the overall osteoarthritis population. There is a lack of evidence to support a protective role of repair or reconstructive surgery of the anterior cruciate ligament or meniscus against osteoarthritis development. A consistent finding in a review of the literature is the often poor reporting of critical study variables, precluding data pooling or a meta-analysis. Osteoarthritis development in the injured joints is caused by intra-articular pathogenic processes initiated at the time of injury, combined with long-term changes in dynamic joint loading. Variation in outcome is reinforced by additional variables associated with the individual such as age, sex, genetics, obesity, muscle strength, activity, and reinjury. A better understanding of these variables may improve future prevention and treatment strategies. In evaluating medical treatment, we now expect large randomized clinical trials complemented by postmarketing monitoring. We should strive toward a comparable level of quality of evidence in surgical treatment of knee injuries. In instances in which a randomized clinical trial is not feasible, natural history and other observational cohort studies need to be as carefully designed and reported as the classic randomized clinical trial, to yield useful information.

Meniscal allografts: indications and outcomes

Meniscal allograft transplantation was introduced into clinical practice now over 20 years ago for the treatment of the symptomatic postmeniscectomy patient who has not yet developed osteoarthritis. Over the years, the indications have been fine-tuned and certain risk factors for failure have been identified. As the number of publications increases steadily, we now know that meniscal allografting significantly reduces pain and improves function. Recent data also suggest a potential chondroprotective effect in a subpopulation of patients. However, the major drawback in all meniscus allograft studies is the general lack of a control population. To improve our knowledge, future prospective studies should include objective outcome tools to evaluate the status of the allograft in addition to the clinical scoring systems. Future research should focus to elucidate the biologic and cellular processes involved in graft repopulation and remodelation.

Clinical diagnosis of potentially treatable early articular cartilage degeneration using optical coherence tomography

A series of bench to operating room studies was conducted to determine whether it is feasible to use optical coherence tomography (OCT) clinically to diagnose potentially reversible early cartilage degeneration. A human cadaver study was performed to confirm the reproducibility of OCT imaging and grading based on identification of changes to cartilage OCT form birefringence using a polarized OCT system approved for clinical use. Segregation of grossly normal appearing human articular cartilage into two groups based on the presence or absence of OCT form birefringence showed that cartilage without OCT form birefringence had reduced ability to increase proteoglycan synthetic activity in response to the anabolic growth factor IGF-1. The bench data further show that IGF-1 insensitivity in cartilage without OCT form birefringence was reversible. To show clinical feasibility, OCT was then used arthroscopically in 19 human subjects. Clinical results confirmed that differences to OCT form birefringence observed in ex vivo study were detectable during arthroscopic surgery. More prevalent loss of cartilage OCT form birefringence was observed in cartilage of human subjects in groups more likely to have cartilage degeneration. This series of integrated bench to bedside studies demonstrates translational feasibility to use OCT for clinical studies on whether human cartilage degeneration can be diagnosed early enough for intervention that may delay or prevent the onset of osteoarthritis.

Anatomic double bundle ACL reconstruction: a literature review

With the abundance of anatomic double bundle ACL reconstruction techniques that currently exist and limited patient outcome data, one has to ask whether or not they should be used and if so, which one, and what is the learning curve for the average knee surgeon to become competent with the technique that they select? The purpose of this literature review is to summarize existing anatomic double bundle ACL reconstruction surgical and rehabilitation techniques and the clinical and biomechanical study evidence that currently exists. In choosing to perform anatomic double bundle ACL reconstruction we suggest that the knee surgeon should look for evidence of: (1) control of the pivot shift phenomenon, (2) improved transverse plane rotatory knee control during the performance of sports type movements, (3) a decreased likelihood of revision procedures either for ACL reconstruction or for treatment of associated primary or recurrent meniscal injuries, (4) improved patient self-reports of perceived function, satisfaction, and quality of life, and (5) radiographic evidence of a lower incidence and/or magnitude of osteoarthritic changes compared to conventional single bundle ACL reconstruction.

Global analyses of gene expression in early experimental osteoarthritis

OBJECTIVE

To analyze genome-wide changes in chondrocyte gene expression in a surgically induced model of early osteoarthritis (OA) in rats, to assess the similarity of this model to human OA, and to identify genes and mechanisms leading to OA pathogenesis.

METHODS

OA was surgically induced in 5 rats by anterior cruciate ligament transection and partial medial meniscectomy. Sham surgery was performed in 5 additional animals, which were used as controls. Both groups underwent 4 weeks of forced mobilization, 3 times per week. RNA was extracted directly from articular chondrocytes in the OA (operated), contralateral, and sham-operated knees. Affymetrix GeneChip expression arrays were used to assess genome-wide changes in gene expression. Expression patterns of selected dysregulated genes, including Col2a1, Mmp13, Adamts5, Ctsc, Ptges, and Cxcr4, were validated by real-time polymerase chain reaction, immunofluorescence, or immunohistochemistry 2, 4, and 8 weeks after surgery.

RESULTS

After normalization, comparison of OA and sham-operated samples showed 1,619 differentially expressed probe sets with changes in their levels of expression > or = 1.5-fold, 722 with changes > or = 2-fold, 135 with changes > or = 4-fold, and 20 with changes of 8-fold. Dysregulated genes known to be involved in human OA included Mmp13, Adamts5, and Ptgs2, among others. Several dysregulated genes (e.g., Reln, Phex, and Ltbp2) had been identified in our earlier microarray study of hypertrophic chondrocyte differentiation. Other genes involved in cytokine and chemokine signaling, including Cxcr4 and Ccl2, were identified. Changes in gene expression were also observed in the contralateral knee, validating the sham operation as the appropriate control.

CONCLUSION

Our results demonstrate that the animal model mimics gene expression changes seen in human OA, supporting the relevance of newly identified genes and pathways to early human OA. We propose new avenues for OA pathogenesis research and potential targets for novel OA treatments, including cathepsins and cytokine, chemokine, and growth factor signaling pathways, in addition to factors controlling the progression of chondrocyte differentiation.

Validity and reliability of functional performance tests in meniscectomized patients with or without knee osteoarthritis

AIMS

Reduced functional performance and muscular dysfunction after knee injury and in knee osteoarthritis (OA) is suggested to be a factor in OA development. Validated functional performance tests applicable in the clinic and large-scale studies are lacking. The aim was to study the reliability and validity of 10 functional performance tests.

METHODS

Two hundred and eighty-five subjects, 15-22 years post-meniscectomy, performed 10 functional performance tests. The mean age was 54 years (SD+/-11.2) and 79% were men; 52% had radiographic OA, and 48% were categorized as symptomatic. The tests were evaluated for test-retest reliability, discriminative ability (younger vs older age, men vs women, symptom-free vs symptomatic) and floor and ceiling effects.

RESULTS

Two of the 10 tests, maximum number of knee bendings in 30 s and one-leg hop for distance, had good test-retest reliability (ICC 0.92, 95% CI 0.86-0.96 and 0.93, 95% CI 0.87-0.97) and were able to discriminate with regard to age, gender and symptoms, and had acceptable floor effects (9% and 3%, respectively).

CONCLUSION

This study suggests the use of two functional performance tests: knee bendings/30 s and one-leg hop for distance, easy to use for evaluation of interventions due to knee injury and knee OA and when attaining long-term data of natural disease history.

Acute rotational trauma to the knee: poor agreement between clinical assessment and magnetic resonance imaging findings

OBJECTIVES

To determine the incidence of anterior cruciate ligament (ACL) injuries in the general population; the pathology associated with a knee sprain verified by magnetic resonance imaging (MRI); and the agreement between clinical findings and MRI.

MATERIAL AND METHODS

Inclusion criterion was an acute rotational trauma to the knee associated with effusion. One hundred and fifty-nine consecutive patients, mean age 27 years and 36% women, were included after clinical assessment at the orthopedic emergency unit. Patients were referred to an MRI examination (1.0 or 1.5 T) performed within a median of 8 days of the initial visit.

RESULTS

The annual incidence of MRI verified ACL injuries was 0.81/1000 inhabitants aged 10-64 years. Fifty-six percent (n=89) of those included had sustained an ACL injury of whom 38% had an associated medial meniscus tear. There was a poor agreement between initial clinical antero-posterior laxity and MRI verified presence of an ACL tear (kappa 0.281). Every second patellar dislocation was diagnosed as a ligament injury.

CONCLUSION

Our findings indicate that the incidence of ACL injuries is higher than previously described. We also show that the first clinical examination after an acute knee trauma has a low diagnostic value. Further assessment with MRI improves the chances of a correct diagnosis of intraarticular pathology and is recommended in the early phase after a rotational knee trauma.

Benefit of single-leaf resection for horizontal meniscus tear

When treating a horizontal meniscus tear, the surgeon must decide whether to resect one or both leaves of the tear. We asked whether there is a biomechanical advantage to sparing one leaf when performing a partial meniscectomy for horizontal meniscus tear. We used pressure-sensitive film to measure the contact area, mean pressure, and peak pressure on the lateral tibial plateau of cadaveric sheep knees loaded to 2x body weight. For tears restricted to the posterior third, single-leaf resection decreased contact area by 40% compared with the intact case. Sparing one leaf was beneficial because resection of the second leaf reduced contact area an additional 15%. Similarly, mean pressure was increased 24% for single-leaf resection and an additional 27% for double-leaf resection. Peak pressure showed no differences with single- and double-leaf resections. For tears that span the entire meniscus, single-leaf resection reduced contact area by 59%, increased mean pressure by 55%, and increased peak pressure by 19%. Double-leaf resection in this situation did not change these values substantially, suggesting sparing one leaf offers no benefit over resecting both leaves with extensive horizontal meniscus tears.

Quantification of meniscal volume by segmentation of 3T magnetic resonance images

Meniscal injuries place the knee at risk for early osteoarthritis (OA) because they disrupt their load-bearing capabilities. Partial resection is routinely performed to alleviate symptomatic meniscal tears. While the removal of meniscal tissue may not be the only factor associated with partial meniscectomy outcome, the amount removed certainly contributes to functional loss. It is unknown, however, whether there is a critical amount of meniscal tissue that can be removed without diminishing the structure's chondroprotective role. In order to examine the existence of such a threshold, it is necessary to accurately quantify meniscal volume both before and after partial meniscectomy to determine the amount of meniscal tissue removed. Therefore, our goal was to develop and validate an MR-based method for assessing meniscal volume. The specific aims were: (1) to evaluate the feasibility of the MR-based segmentation method; (2) to determine the method's reliability for repeated measurements; and (3) to validate its accuracy in situ. MR images were obtained on a 3T magnet, and each scan was segmented using a biplanar approach. The MR-based volumes for each specimen were compared to those measured by water displacement. The results indicate that the biplanar approach of measuring meniscal volumes is accurate and reliable. The calculated volumes of the menisci were within 5% of the true values, the coefficients of variation were 4%, and the intraclass correlation coefficients were greater than 0.96. These data demonstrate that this method could be used to measure the amount of meniscal tissue excised during partial meniscectomy to within 125.7 mm(3).

Muscle strength, functional performance, and self-reported outcomes four years after arthroscopic partial meniscectomy in middle-aged patients

OBJECTIVE

To examine thigh muscle strength, functional performance, and self-reported outcome in patients with nontraumatic meniscus tears 4 years after operation, and to study the impact of a strength deficit on self-reported outcome and evaluate the feasibility of 3 performance tests in this patient group.

METHODS

The study group comprised 45 patients (36% women, mean age 46.7) who had an arthroscopic partial meniscectomy a mean of 4 years (range 1-6 years) previously. Main outcome measures included isokinetic strength of knee extensors and flexors, functional performance (1-leg hop, 1-leg rising, and square-hop tests), and a self-reported questionnaire (Knee Injury and Osteoarthritis Outcome Score).

RESULTS

We found lower knee extensor strength and worse 1-leg rising capacity in the operated leg, but no difference between operated and nonoperated leg for knee flexors (P < or = 0.004 and P > 0.3, respectively). Patients with a stronger quadriceps of the operated leg compared with the nonoperated leg had less pain and better function and quality of life (r = 0.4-0.6, P < or = 0.010). We found the 1-leg rising and 1-leg hop tests to be suitable performance tests in middle-aged meniscectomy patients.

CONCLUSION

Quadriceps strength is reduced in the meniscectomized leg compared with the nonoperated leg 4 years after surgery. This relative quadriceps weakness significantly affects objective and self-reported knee function, pain, and quality of life, indicating the importance of restoring muscle function after meniscectomy in middle-aged patients.

A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial

OBJECTIVE

To examine the effectiveness of a sport-specific balance training program in reducing injury in adolescent basketball.

DESIGN

Cluster randomized controlled trial.

SETTING

Twenty-five high schools in Calgary and surrounding area.

SUBJECTS

Nine hundred and twenty high school basketball players (ages 12-18).

INTERVENTION

Subjects were randomly allocated by school to the control (n = 426) and training group (n = 494). Both groups were taught a standardized warm-up program. The training group was also taught an additional warm-up component and a home-based balance training program using a wobble board.

MAIN OUTCOME MEASURES

All injuries occurring during basketball that required medical attention and/or caused a player to be removed from that current session and/or miss a subsequent session were then recorded and assessed by a team therapist who was blinded to training group allocation.

RESULTS

A basketball-specific balance training program was protective of acute-onset injuries in high school basketball [RR = 0.71 (95% CI; 0.5-0.99)]. The protective effect found with respect to all injury [RR = 0.8 (95% CI; 0.57-1.11)], lower-extremity injury [RR = 0.83 (95% CI; 0.57-1.19)], and ankle sprain injury [RR = 0.71 (95% CI; 0.45-1.13)] were not statistically significant. Self-reported compliance to the intended home-based training program was poor (298/494 or 60.3%).

CONCLUSIONS

A basketball-specific balance training program was effective in reducing acute-onset injuries in high school basketball. There was also a clinically relevant trend found with respect to the reduction of all, lower-extremity, and ankle sprain injury. Future research should include further development of neuromuscular prevention strategies in addition to further evaluation of methods to increase compliance to an injury-prevention training program in adolescents.

To run or not to run: a post-meniscectomy qualitative risk analysis model for osteoarthritis when considering a return to recreational running

The increased likelihood of osteoarthritic change in the tibiofemoral joint following meniscectomy is well documented. This awareness often leads medical practitioners to advise patients previously engaged in recreational running who have undergone meniscectomy to cease all recreational running. This literature review examines the following questions: 1) Is there evidence to demonstrate that runners, post-meniscectomy, incur a great enough risk for early degenerative OA to cease all running? 2) Does the literature yield risk factors for early OA that would guide a physical therapist with regard to advising the post-meniscectomy patient contemplating a return to recreational running? Current literature related to meniscal structure and function, etiology and definition of osteoarthritis, methods for assessing osteoarthritis, relationship between running and osteoarthritis, and relationship between meniscectomy and osteoarthritis are reviewed. This review finds that while the probability for early osteoarthritis in the post-meniscectomy population is substantial, it is a probability and not a certainty. To help guide a physical therapist with regard to advising the patient for a safe return to running following a meniscectomy, a qualitative risk assessment based on identified risk factors for osteoarthritis in both the running and the post-meniscectomy populations is proposed.

Meniscal allograft transplantation: long-term clinical results with radiological and magnetic resonance imaging correlations

Long-term data on the clinical outcome and the fate of the meniscus allograft after transplantation are scarce. In this study we present the clinical, radiological and MRI outcome of the meniscus graft and the articular cartilage after 42 meniscus allograft transplantations in 41 patients with a minimum follow-up of 10 years. A total of 27 medial and 15 lateral meniscal allografts were transplanted. Eleven of the medial allograft procedures were associated with a high tibial osteotomy. The patients were evaluated clinically at the time of transplantation and at the final follow-up using the modified HSS scoring system. The knee injury and osteoarthritis outcome score (KOOS) was used as an evaluation tool for patient-related outcome at the final follow-up. Joint space width narrowing and Fairbank changes were radiological outcome parameters, which were available for 32 patients. Femoral and tibial cartilage degeneration, graft extrusion and signal intensity were scored on MRI scans obtained in 17 patients approximately 1 year after transplantation and at the final follow-up (>10 years). For statistical analysis the patients were divided into three groups: lateral meniscal allograft (LMT), medial meniscal allograft transplantation with a high tibial osteotomy (MMT+HTO) and without (MMT). The modified HSS score revealed a significant improvement in pain and function at the final follow-up for all groups. Further analysis also revealed that an MMT+HTO procedure resulted in a greater improvement at the final follow-up when compared to MMT. Nonetheless, the KOOS scores obtained at the final follow-up revealed the presence of substantial disability and symptoms, in addition to a reduced quality of life. Radiographical analysis revealed no further joint space narrowing in 13/32 knees (41%). Fairbank changes remained stable in 9/32 knees (28%). MRI analysis showed no progression of cartilage degeneration in 6/17 knees (35%). An increased signal intensity of the allograft was present, as was partial graft extrusion in the majority of patients at the final follow-up. Seven cases had to be converted to a total knee arthroplasty during the follow-up; the overall failure rate was 18%. Long-term results after viable meniscus allograft transplantation are encouraging in terms of pain relief and improvement of function. Despite this significant improvement, substantial disability and symptoms were present in all investigated subgroups. Progression of further cartilage degeneration or joint space narrowing was absent in a considerable number of cases, indicating a potential chondroprotective effect. Level of evidence is therapeutic study, Level IV and retrospective analysis of prospectively collected data.

Knee kinematics and kinetics during gait, step and hop in males with a 16 years old ACL injury compared with matched controls

The objective of this study was to compare subjects who sustained an ACL injury during soccer 16 years ago with a control group with regard to knee kinematics and kinetics of gait, step activity and cross over hop. Secondly, in the injured subjects, the purpose was to study the impact on kinematics and kinetics of characteristics such as operative status, meniscal resection, being symptomatic, having knee extensor weakness and of having radiographic knee OA. Data from a 3-dimensional gait analysis system (VICON) were used to calculate kinetics and kinematics during gait, step activity and cross over hop of 12 male subjects who had an anterior cruciate ligament injury 16 years earlier. Twelve uninjured subjects matched for age, sex, BMI and activity level served as controls. No significant differences in knee kinematics and kinetics between the ACL group and the control group were found. The variability of some parameters of step and all parameters of hop activity was generally larger in the ACL injured subjects compared with the controls. The ACL injured subjects had a significantly worse clinical status compared with the controls. Reduced knee extension strength was associated with joint moment reductions especially during step activity and cross over hop. Despite a significantly worse clinical status, as determined by self-report and isokinetic strength testing, no significant differences were seen in knee joint kinetics and kinematics in an ACL injured group 16 years after injury compared with a matched control group. The variation was larger among the ACL injured subjects indicating the need for larger study groups in gait and movement analysis in long-term follow-up of ACL injury.

Retropatellar chondromalacia associated with medial osteoarthritis after meniscus injury. One year of observations in sheep

BACKGROUND/AIMS

In an ovine meniscal repair model, the patellofemoral (PF) osteoarthritis due to a non-sutured tear or failed repair was investigated.

METHODS

A radial meniscus tear was either sutured with polydioxanone (PDS), with a slow degrading polylactide long-term suture(LTS) or left without treatment. Knee joint cartilage in the PF and medial compartment was evaluated compared to normal knees (healthy controls).

RESULTS

Retropatellar osteoarthritis in the non-sutured and sutured animals was intense in contrast to the control knees after 6 months in all groups (p < 0.001), and after 12 months in the PDS group (p < 0.001), LTS group and non-sutured animals (p < 0.05).

CONCLUSION

Non-sutured meniscus tears and failed repair lead fast to intense PF osteoarthritis corresponding with tibial damage of the injured compartment.

Quantifying peri-meniscal synovitis and its relationship to meniscal pathology in osteoarthritis of the knee

The objectives of this study were to validate a semiquantitative scoring system for estimating perimeniscal synovitis in osteoarthritic (OA) knees and to examine the relationship between the extent of synovitis and the degree of meniscal pathology using gadolinium-enhanced magnetic resonance imaging (MRI). Forty-three subjects with clinically diagnosed OA knee were assessed for peri-meniscal synovitis using gadolinium-enhanced MRI. Quantitative measurements of synovitis were made by summing areas in consecutive slices within generated regions of interest, and the synovitis was also scored semi-quantitatively using a 0-3 scale. Meniscal pathology (extrusion, degeneration and tearing) was also scored semiquantitatively. Establishment of a correlative relationship was undertaken using Spearman's rho (rho). A total of 86 sites were assessed. The semi-quantitative synovitis score correlated well with the quantitative synovitis score (rho>0.9). A moderate association between medial meniscal extrusion and synovitis was demonstrated (rho=0.762, P<0.000), although this association was not as strong in the lateral compartment (rho=0.524, P<0..000). The results suggest the semiquantitative scoring system is valid for assessing perimeniscal synovitis. The relationship between meniscal pathology and adjacent synovitis requires further study.

The association of meniscal pathologic changes with cartilage loss in symptomatic knee osteoarthritis

OBJECTIVE

To explore the role of meniscal tears and meniscal malposition as risk factors for subsequent cartilage loss in subjects with symptomatic osteoarthritis (OA).

METHODS

Study subjects were patients with symptomatic knee OA from the Boston Osteoarthritis of the Knee Study. Baseline assessments included knee magnetic resonance imaging (MRI) with followup MRI at 15 and 30 months. Cartilage and meniscal damage were scored on MRI in the medial and lateral tibiofemoral joints using the semiquantitative whole-organ magnetic resonance imaging score. Tibiofemoral cartilage was scored on MR images of all 5 plates of each tibiofemoral joint, and the meniscal position was measured using eFilm Workstation software. A proportional odds logistic regression model with generalized estimating equations was used to assess the effect of each predictor (meniscal position factor and meniscal damage as dichotomous predictors in each model) on cartilage loss in each of the 5 plates within a compartment. Models were adjusted for age, body mass index (BMI), tibial width, and sex.

RESULTS

We assessed 257 subjects whose mean +/- SD age was 66.6 +/- 9.2 years and BMI was 31.5 +/- 5.7 kg/m2; 42% of subjects were female, and 77% of knees had a Kellgren/Lawrence radiographic severity grade > or = 2. In the medial tibiofemoral joint, each measure of meniscal malposition was associated with an increased risk of cartilage loss. There was also a strong association between meniscal damage and cartilage loss. Since meniscal coverage and meniscal height diminished with subluxation, less coverage and reduced height also increased the risk of cartilage loss.

CONCLUSION

This study highlights the importance of an intact and functioning meniscus in patients with symptomatic knee OA, since the findings demonstrate that loss of this function has important consequences for cartilage loss.

Most recent developments in strategies to reduce the progression of structural changes in osteoarthritis: today and tomorrow

Osteoarthritis (OA), the most common of all arthritic conditions, is a social and financial burden to all nations. The most recent research has significantly advanced our understanding of the cause of OA and risk factors associated with it. These findings have provided useful information that has helped in the daily management of patients with OA. Some preventative measures and a number of therapeutic agents and drugs are available, which may help to reduce the progression of OA in certain patients. Moreover, the most recent progress in research has significantly enhanced our knowledge of the factors involved in the development of the disease and of the mechanisms responsible for its progression. This has allowed identification of several new therapeutic targets in a number of pathophysiological pathways. Consequently, the field is opening up to a new era in which drugs and agents that can specifically block important mechanisms responsible for the structural changes that occur in OA can be brought into development and eventually into clinical trials.

Biaxial strain effects on cells from the inner and outer regions of the meniscus

During knee joint loading, the fibrocartilaginous menisci experience significant spatial variations in mechanical stimuli. Meniscus cells also exhibit significant variations in biosynthesis and gene expression depending on their location within the tissue. These metabolic patterns are consistent with a more chondrocytic phenotype for cells located within the avascular inner two-thirds compared with a more fibroblastic phenotype for cells within the vascularized outer periphery. The spatial distribution of cell biosynthesis and gene expression patterns within the meniscus suggest that cells may exhibit intrinsically different responses to mechanical stimuli. The objective of our study was to test for intrinsic differences in the responsiveness of these meniscus cell populations to an equivalent mechanical stimulus. Cellular biosynthesis and gene expression for extracellular matrix proteins in isolated inner and outer meniscus cells in monolayer were quantified following cyclic biaxial stretch. The results demonstrate that inner and outer meniscus cells exhibit significant differences in matrix biosynthesis and gene expression regardless of stretching condition. Both inner and outer meniscus cells responded to stretch with increased nitric oxide production and total protein synthesis. The results suggest that inner and outer meniscus cells may respond similarly to biaxial stretch in vitro with measures of biosynthesis and gene expression.

Positive effects of moderate exercise on glycosaminoglycan content in knee cartilage: a four-month, randomized, controlled trial in patients at risk of osteoarthritis

OBJECTIVE

To evaluate the effects of moderate exercise on glycosaminoglycan (GAG) content in knee cartilage in subjects at high risk of knee osteoarthritis (OA).

METHODS

Forty-five subjects (16 women, mean age 46 years, mean body mass index 26.6 kg/m(2)) who underwent partial medial meniscus resection 3-5 years previously were randomized to undergo a regimen of supervised exercise 3 times weekly for 4 months or to a nonintervention control group. Cartilage GAG content, an important aspect of the biomechanical properties of cartilage, was estimated by delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), with results expressed as the change in the T1 relaxation time in the presence of Gd-DTPA (T1[Gd]).

RESULTS

Thirty of 45 patients were examined by dGEMRIC at baseline and followup. The exercise group (n = 16) showed an improvement in the T1(Gd) compared with the control group (n = 14) (15 msec versus -15 msec; P = 0.036). To study the dose response, change in the T1(Gd) was assessed for correlation with self-reported change in physical activity level, and a strong correlation was found in the exercise group (n = 16, r(S) = 0.70, 95% confidence interval [95% CI] 0.31-0.89) and in the pooled group of all subjects (n = 30, r(S) = 0.74, 95% CI 0.52-0.87).

CONCLUSION

This in vivo cartilage monitoring study in patients at risk of knee OA who begin exercising indicates that adult human articular cartilage has a potential to adapt to loading change. Moderate exercise may be a good treatment not only to improve joint symptoms and function, but also to improve the knee cartilage GAG content in patients at high risk of developing OA.