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

Long-term results of a randomized study on anterior cruciate ligament reconstruction with or without a synthetic degradable augmentation device to support the autograft

PURPOSE

The aim was to compare the outcome of anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autograft, with and without a poly(urethane urea) augmentation device.

METHODS

Patients were randomized to BPTB reconstruction with a synthetic degradable augmentation device (n = 96) or without augmentation (n = 105). Follow-ups were made during 4 years after surgical treatment with the KT1000 arthrometer for objective evaluation of sagittal stability. The Tegner scoring system for assessment of physical activity level and the Knee injury Osteoarthritis Outcome Score (KOOS) for assessment of knee-specific health were evaluated after 4 and 12 years.

RESULTS

KT1000 tests showed a significant decrease in mean manual maximum side-to-side difference after 4 years in both patients with and those without augmentation, without any statistical difference between the groups (n.s.). Pre-injury, 76 and 80% of the patients, respectively, reported Tegner level 7-10. Pre-surgery, the corresponding figures were 6 and 5%, and at 4 years, 33 and 30 %. Twelve years after ACL reconstruction, both groups had significantly higher KOOS scores in function in sports and recreational activities (p < 0.001) and knee-related quality of life (p < 0.001) compared to before surgical treatment. In 10 patients, the augmentation device was removed, in six of these because of insufficient screw fixation to femur and in four due to swelling/hydrops.

CONCLUSION

This study showed no significant difference in clinical outcome with use of an additional synthetic augmentation device in a single-bundle BPTB ACL reconstruction compared with non-augmentation, in short, intermediate, or long-term perspective.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Vertical Tears of the Lateral Meniscus: Effects on In Vitro Tibiofemoral Joint Mechanics

BACKGROUND

Lateral meniscal tears are often seen with acute anterior cruciate ligament (ACL) injury and may be left in situ, repaired, or treated with meniscectomy. Clinical studies have shown good outcomes with vertical tears left in situ and poor outcomes following meniscectomy. However, clinically relevant studies are needed to establish a biomechanical foundation for treatment of these tears, particularly regarding the effects of meniscectomy.

PURPOSE

To compare tibiofemoral joint mechanics following vertical lateral meniscal tears and meniscectomies. We hypothesized that a peripheral vertical tear of the lateral meniscus would alter joint mechanics, increasing contact pressure and area, and that more drastic effects would be seen following meniscectomy, at higher knee flexion angles, and with increased loads.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten fresh-frozen cadaveric knees (average age, 55 ± 12 years) were tested with 5 lateral meniscus states: intact, short vertical tear, extended vertical tear, posterior horn partial meniscectomy (rim intact), and posterior horn subtotal meniscectomy (rim excised). The specimens were loaded axially at knee flexion angles of 0°, 30°, and 60°, and musculotendinous forces were applied, simulating a 2-legged squat. Intra-articular contact pressures were measured using pressure-sensitive Fuji film. Kinematic data were acquired through digitization of fiducial markers.

RESULTS

Vertical tears did not cause a significant change in contact pressure or area. Partial meniscectomy increased maximum contact pressures in the lateral compartment at 30° and 60° from 5.3 MPa to 7.2 MPa and 7.6 MPa, respectively (P = .02, P = .007). Subtotal meniscectomy (8.4 MPa) significantly increased contact pressure compared with partial meniscectomy (7.6 MPa) at 60° (P = .04). Both meniscectomy states significantly increased contact pressures with increasing flexion from 0° to 60° (P < .001, P < .001).

CONCLUSION

Vertical tears of the lateral meniscus during a simulated 2-legged squat did not significantly change contact pressures and areas compared with an intact meniscus. However, treating these tears with partial and complete meniscectomy significantly increased maximum contact pressures.

CLINICAL RELEVANCE

Biomechanical evidence supports treating vertical lateral meniscus tears with meniscal-sparing techniques as opposed to meniscectomy, which may lead to progressive degenerative joint disease from altered joint biomechanics.

Population-wide incidence estimates for soft tissue knee injuries presenting to healthcare in southern Sweden: data from the Skåne Healthcare Register

Introduction

Soft tissue knee injury is a well-established and potent risk factor for development of knee osteoarthritis. However, there is a paucity of epidemiological data from the general population. Our aim was to estimate the annual person-level incidence for a wide spectrum of clinically diagnosed soft tissue knee injuries, and their distribution by age, sex, and season.

Methods

In Sweden, in- and outpatient health care is registered using each individuals’ unique personal identifier including International Classification of Diseases (ICD) 10 diagnostic code(s) as determined by physicians’ clinical examination. For the calendar years 2004–2012, we studied the population in southern Sweden, Skåne region (approx. 1.3 million). We identified residents who had at least one visit to a physician with clinically diagnosed knee ligament, meniscal, or other soft-tissue injury (S80.0, S83 and all subdiagnoses). We then calculated the mean annual incidence over the 9-year period. As a secondary objective, we investigated potential seasonal variation.

Results

The annual incidence for males and females was 766 (95% CI: 742, 789) and 676 (649, 702) per 100,000 persons/year respectively. For males and females, the peak rate occurred in 15 to 19 year-olds (1698 per 100,000 men and 1464 per 100,000 women, respectively). In women, rates were lowest in the 25 to 34 year-old age range before rising again between the ages of 35 and 49 years. We found substantial seasonal variation, greatest in men, with peaks in March-May and August-October.

Conclusions

The incidence of clinically diagnosed soft-tissue knee injury peaks in adolescence and emerging adulthood. However, a range of knee injuries continue to occur across the adult lifespan including at ages when osteoarthritis is typically diagnosed and managed. The potential cumulative effect on osteoarthritis progression of these injuries may warrant further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/ar4678) contains supplementary material, which is available to authorized users.

Physiological and excessive mechanical compression of articular cartilage activates Smad2/3P signaling

OBJECTIVE

Transforming growth factor beta (TGF-β) in articular cartilage can signal via two routes, the ALK5/Smad2/3P and the ALK1/Smad1/5/8P route, the first being protective and the latter favoring chondrocyte terminal differentiation. Since biomechanical factors are known to play an essential role in osteoarthritis (OA) initiation and progression, we investigated if excessive mechanical compression can alter TGF-β signaling in cartilage shifting it from ALK5/Smad2/3P to ALK1/Smad1/5/8P pathway, favoring terminal differentiation of chondrocytes.

DESIGN

Articular cartilage explants were harvested from bovine metacarpophalangeal joints. After equilibration, explants were subjected to unconfined dynamic mechanical compression (1 Hz) with 3 MPa (physiological) or 12 MPa (excessive) stress. After different time intervals samples were frozen and mRNA levels of selected genes were examined using real-time polymerase chain reaction.

RESULTS

In articular cartilage compressed with 3 MPa and also 12 MPa stress the expression of Smad2/3P responsive genes bSerpine1, bSmad7 and bAlk5 was up-regulated, whereas the expression of Smad1/5/8P responsive gene bId1 was down-regulated. Furthermore, the expression of bTgfb1 was significantly up-regulated in both compression groups. When ALK5/Smad2/3P pathway was blocked with a selective ALK4/5/7 inhibitor, the effect of excessive mechanical compression on bSmad7 and bAlk5 expression was prevented.

CONCLUSIONS

Here we show that excessive mechanical compression alone is not able to shift TGF-β signaling toward the ALK1/Smad1/5/8P pathway. In contrast, we show that mechanical compression not only with physiological but also with excessive stress can activate Smad2/3P signaling, which is known to be protective for articular cartilage and to block chondrocyte terminal differentiation.

Meniscal tear as potential steering factor for inflammation may aggravate arthritis: two case reports

INTRODUCTION

Meniscal tear is thought to play a crucial role in onset as well as progression of arthritis. However, role of cytokine response to meniscal injury and resulting inflammation is not clearly understood. Because synovial fluid is juxtaposed to cartilage and serves as a biological connection between chondrocytes and synoviocytes, we chose synovial fluid analysis to ascertain biochemical response associated with a meniscal tear.

CASE PRESENTATION

We report the cases of two patients with clinically different inflammatory arthritis, both of whom are Indian men. Patient 1 was 30 years of age, and patient 2 was 50 years of age. They both had a history of meniscal tear, which we confirmed by magnetic resonance imaging scans. Synovial fluid samples obtained from these two patients were analyzed for proinflammatory markers, such as interleukin 1β (IL-1β) and nitric oxide, and also for glycosaminoglycan as a cartilage degradation indicator. Relatively high levels of IL-1β (2000.0 ± 15.7 pg/ml) and nitric oxide (4.73 ± 0.05 μM/ml) and relatively low glycosaminoglycan (93.75 ± 6.3 μg/ml) were observed in patient 1, corroborating the diagnosis of traumatic meniscal tear. Compared to patient 1, Patient 2 had relatively low levels of IL-1β (54.55 ± 14.5 pg/ml) and nitric oxide (20.00 ± 0.6 μM/ml) and remarkably high glycosaminoglycan levels (553.33 ± 1.7 μg/ml), coupled with significant osteophytes and profound cartilage loss, which indicated severe arthritis and a diagnosis of degenerative meniscal tear.

CONCLUSION

The elevated levels of inflammatory IL-1β aggravated the severity of arthritis attributable to meniscal tear in both patients, as found in follow-up visits. This was quite evident in patient 2, whereas patient 1, being younger, had less serious symptoms. Meniscal tear has emerged as a potential confounding factor in arthritis with different clinical backgrounds, which leads to increased levels of inflammation and results in accelerated disease progression.

Mesenchymal stem cells in synovial fluid increase after meniscus injury

BACKGROUND

Although relatively uncommon, spontaneous healing from a meniscus injury has been observed even within the avascular area. This may be the result of the existence of mesenchymal stem cells in synovial fluid.

QUESTIONS/PURPOSES

The purpose of this study was to investigate whether mesenchymal stem cells existed in the synovial fluid of the knee after meniscus injury.

METHODS

Synovial fluid was obtained from the knees of 22 patients with meniscus injury just before meniscus surgery and from 8 volunteers who had no history of knee injury. The cellular fraction of the synovial fluid was cultured for 14 days followed by analysis for multilineage potential and presentation of surface antigens characteristic of mesenchymal stem cells. Colony-forming efficiency and proliferation potential were also compared between the two groups.

RESULTS

Cells with characteristics of mesenchymal stem cells were observed in the synovial fluid of injured knees to a much greater degree than in uninjured knees. The colony-forming cells derived from the synovial fluid of the knee with meniscus injury had multipotentiality and surface epitopes identical to mesenchymal stem cells. The average number of colony formation, obtained from 1 mL of synovial fluid, in meniscus-injured knees was 250, higher than that from healthy volunteers, which was 0.5 (p < 0.001). Total colony number per synovial fluid volume was positively correlated with the postinjury period (r = 0.77, p < 0.001).

CONCLUSIONS

Mesenchymal stem cells were found to exist in synovial fluid from knees after meniscus injury. Mesenchymal stem cells were present in higher numbers in synovial fluid with meniscus injury than in normal knees. Total colony number per synovial fluid volume was positively correlated with the postinjury period.

CLINICAL RELEVANCE

Our current human study and previous animal studies suggest the possibility that mesenchymal stem cells in synovial fluid increase after meniscus injury contributing to spontaneous meniscus healing.

Post-traumatic knee osteoarthritis in the young patient: therapeutic dilemmas and emerging technologies

Traumatic knee injury is common in young adults and strongly contributes to premature development of knee osteoarthritis (OA). Post-traumatic knee OA poses a therapeutic dilemma to the physician, since no known therapy has an acceptable safety profile, effectively relieves joint pain, and enjoys reasonable patient acceptance. Consequently, these young patients will ultimately be faced with the decision to either undergo surgical intervention, despite prosthesis durability concerns, or to continue with ineffective nonsurgical treatment. Emerging therapies, such as biologics, disease-modifying drugs, partial joint resurfacings, and minimally invasive joint-unloading implants are currently being studied to fill this therapeutic void in the young patient with post-traumatic knee OA.

A multilayer tissue engineered meniscus substitute

Various methods have been tried to treat the main meniscus problem, meniscal tears, for which we believe tissue engineering could be a viable solution. In this study, a three dimensional, collagen-based meniscus substitute was prepared by tissue engineering using human fibrochondrocytes and a collagen based-scaffold. This construct was made with 3 different collagen-based foams interspaced with two electrospun nano/microfibrous mats. The top layer was made of collagen type I-chondroitin sulfate-hyaluronic acid (Coll-CS-HA), and the middle and the bottom layers were made of only collagen type I with different porosities and thus with different mechanical properties. The mats of aligned fibers were a blend of collagen type I and poly(L-lactic acid-co-glycolic acid) (PLGA). After seeding with human fibrochondrocytes, cell attachment, proliferation, and production of extracellular matrix and glucoseaminoglycan were studied. Cell seeding had a positive effect on the compressive properties of foams and the 3D construct. The 3D construct with all its 5 layers had better mechanical properties than the individual foams.

Meniscal pathology - the evidence for treatment

Whilst arthroscopic surgery for the treatment of meniscal tears is the most commonly performed orthopaedic surgery, meniscal tears at the knee are frequently identified on magnetic resonance imaging in adults with and without knee pain. The evidence for arthroscopic treatment of meniscal tears is controversial and lacks a supporting evidence base; it may be no more efficacious than conservative therapies. Surgical approaches to the treatment of meniscal pathology can be broadly categorised into those in which partial menisectomy or repair are performed. This review highlights that the major factor determining the choice of operative approach is age: meniscal repair is performed exclusively on younger populations, while older populations are subject to partial menisectomy procedures. This is probably because the meniscus is less amenable to repair in the older population where other degenerative changes co-exist. In middle-aged to older adults, arthroscopic partial menisectomy (APM) may treat the meniscus tear, but does not address the degenerative whole organ disease of knee osteoarthritis. Thus far, there is no convincing evidence that operative approaches are superior to conservative measures as the first-line treatment of older people with knee pain and meniscal tears. However, in two randomised controlled trials (RCTs) approximately one-third of subjects in the exercise groups had persisting knee pain with some evidence of improvement following APM, although the characteristics of this subgroup are unclear. From the available data, a first-line trial of conservative therapy, which includes weight loss, is recommended for the treatment of degenerative meniscal tears in older adults. The exception to this may be when mechanical symptoms, such as knee locking, predominate. Although requiring corroboration by RCTs, there is accumulating evidence from cohort studies and case series that meniscal repair rather than APM may improve function and reduce the long-term risk of knee osteoarthritis in young adults. There is no clear evidence from RCTs that one surgical method of meniscal repair is superior to another.

Discoid lateral meniscus tears and concomitant articular cartilage lesions in the knee

PURPOSE

The purpose of this study was to investigate the relation between isolated discoid lateral meniscus (DLM) tears and the presence of articular cartilage lesions.

METHODS

From January 2010 to January 2012, 252 consecutive patients diagnosed with an isolated DLM tear during an arthroscopic procedure were included in this study. Demographic variables, including gender, age, body mass index (BMI), traumatic history, time course, and date of the DLM tear, were recorded. The relation between DLM tears and the presence of articular cartilage lesions was analyzed by the χ(2) test. Logistic regression analysis was used to analyze the relation between these variables and articular cartilage lesions.

RESULTS

Of the patients with DLM tears, 67 (26.6%) also had articular cartilage lesions. The most common type of DLM tear was the complex tear (46.8%). The most common location of articular cartilage lesions was the lateral tibial plateau (11.6%). Lesions on the opposing articular surfaces of the lateral compartment and patellofemoral joint of the knee were found in 12 patients (4.8%) and 11 patients (4.4%), respectively. There were no significant differences in the incidences of articular cartilage lesions in patients with different types of DLM tears (P > .05). Gender (odds ratio [OR], 2.289; P = .012), BMI (OR, 1.991; P = .023), and time course (OR, 2.050; P = .034) were significantly associated with articular cartilage lesions.

CONCLUSIONS

DLM tears were more common in the context of degenerative tears. There was no significant difference in the incidence of articular cartilage lesions among patients with different types of DLM tears. Female patients, patients with a BMI greater than 23.0 kg/m(2), or patients with a time course of greater than 6 months were more frequently observed to also have articular cartilage lesions.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The use of blood vessel-derived stem cells for meniscal regeneration and repair

PURPOSE

Surgical repairs of tears in the vascular region of the meniscus usually heal better than repairs performed in the avascular region; thus, we hypothesized that this region might possess a richer supply of vascular-derived stem cells than the avascular region.

METHODS

In this study, we analyzed 6 menisci extracted from aborted human fetuses and 12 human lateral menisci extracted from adult human subjects undergoing total knee arthroplasty. Menisci were immunostained for CD34 (a stem cell marker) and CD146 (a pericyte marker) in situ, whereas other menisci were dissected into two regions (peripheral and inner) and used to isolate meniscus-derived cells by flow cytometry. Cell populations expressing CD34 and CD146 were tested for their multilineage differentiation potentials, including chondrogenic, osteogenic, and adipogenic lineages. Fetal peripheral meniscus cells were transplanted by intracapsular injection into the knee joints of an athymic rat meniscal tear model. Rat menisci were extracted and histologically evaluated after 4 wk posttransplantation.

RESULTS

Immunohistochemistry and flow cytometric analyses demonstrated that a higher number of CD34- and CD146-positive cells were found in the peripheral region compared with the inner region. The CD34- and CD146-positive cells isolated from the vascular region of both fetal and adult menisci demonstrated multilineage differentiation capacities and were more potent than cells isolated from the inner (avascular) region. Fetal CD34- and CD146-positive cells transplanted into the athymic rat knee joint were recruited into the meniscal tear sites and contributed to meniscus repair.

CONCLUSIONS

The vascularized region of the meniscus contains more stem cells than the avascular region. These meniscal-derived stem cells were multipotent and contributed to meniscal regeneration.

Regenerative repair of damaged meniscus with autologous adipose tissue-derived stem cells

Mesenchymal stem cells (MSCs) are defined as pluripotent cells found in numerous human tissues, including bone marrow and adipose tissue. Such MSCs, isolated from bone marrow and adipose tissue, have been shown to differentiate into bone and cartilage, along with other types of tissues. Therefore, MSCs represent a promising new therapy in regenerative medicine. The initial treatment of meniscus tear of the knee is managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. When such conservative treatment fails, an arthroscopic resection of the meniscus is necessary. However, the major drawback of the meniscectomy is an early onset of osteoarthritis. Therefore, an effective and noninvasive treatment for patients with continuous knee pain due to damaged meniscus has been sought. Here, we present a review, highlighting the possible regenerative mechanisms of damaged meniscus with MSCs (especially adipose tissue-derived stem cells (ASCs)), along with a case of successful repair of torn meniscus with significant reduction of knee pain by percutaneous injection of autologous ASCs into an adult human knee.

Electrical stimulation enhances cell migration and integrative repair in the meniscus

Electrical signals have been applied towards the repair of articular tissues in the laboratory and clinical settings for over seventy years. We focus on healing of the meniscus, a tissue essential to knee function with limited innate repair potential, which has been largely unexplored in the context of electrical stimulation. Here we demonstrate for the first time that electrical stimulation enhances meniscus cell migration and integrative tissue repair. We optimize pulsatile direct current electrical stimulation parameters on cells at the micro-scale, and apply these to healing of full-thickness defects in explants at the macro-scale. We report increased expression of the adenosine A_2b receptor in meniscus cells after stimulation at the micro- and macro-scale, and propose a role for A_2bR in meniscus electrotransduction. Taken together, these findings advance our understanding of the effects of electrical signals and their mechanisms of action, and contribute to developing electrotherapeutic strategies for meniscus repair.

Is postoperative exercise therapy necessary in patients with degenerative meniscus? A randomized controlled trial with one year follow-up

PURPOSE

There is no consensus on a postoperative rehabilitation regimen for patients who have undergone surgery for medial meniscus damage. The aim of this investigation was to evaluate two rehabilitation approaches after arthroscopic surgery in patients with degenerative meniscus: supervised medical exercise therapy versus no treatment.

METHODS

A prospective randomized controlled clinical trial. Over 4 months, 70 participants were randomly assigned into either a medical exercise therapy group (n = 36) or a control group (n = 34). Pain was a composite score of a visual analogue scale (VAS), and function was measured with a functional assessment questionnaire (KOOS), while anxiety and depression were measured with the Hospital Anxiety and Depression Scale. Function was also measured with tests of quadriceps femoris strength and a one-leg jump test.

RESULTS

Prognostic variables were similar between the groups at baseline, with five (7 %) patients dropping out during the treatment period and another six (8 %) before the one-year follow-up. After 3 months, the medical exercise therapy group achieved significantly better outcome effects than the control group for pain and function. The results after the 12-month follow-up indicated the same results as at posttest, whereas Hospital Anxiety and Depression Scale, fiveRM and the one-leg hop test also demonstrated a significant difference between the groups from pre- to posttest to follow-up.

CONCLUSION

In patients with surgery for degenerative meniscus damage, postoperative medical exercise therapy is an efficient treatment alternative compared to no treatment.

Knee cartilage assessment with MRI (dGEMRIC) and subjective knee function in ACL injured copers: a cohort study with a 20 year follow-up

OBJECTIVE

To assess knee cartilage quality and subjective knee function, 20 years after injury in anterior cruciate ligament (ACL) injured copers.

METHOD

We examined 32 knees using delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC), 20 years after a complete ACL tear. Only subjects who had coped with the ACL injury without ACL reconstruction (ACLR), and who presented without radiographic signs of osteoarthritis (OA) at an earlier 16-year follow-up, were included in this study. The quality of the central weight-bearing parts of the medial and lateral femoral cartilage was estimated with dGEMRIC (T1Gd). These results were compared with corresponding results in 24 healthy individuals, and with the subjects' self-reported subjective knee function using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire.

RESULTS

The values of T1Gd in the medial and lateral femoral cartilage of the study group (mean (95% CI)), were 404 (385-423) and 427 (399-455) ms, not statistically different from those of the healthy reference group (P = 0.065 and 0.31). The subjective knee function 20 years after the injury, according to the five domains of the KOOS score, was good, with a mean score of 90 ± 11. Values of T1Gd for the medial femoral cartilage were correlated with the KOOS subgroup QOL (P = 0.021, Pearson correlation).

CONCLUSIONS

Subjects who have managed to cope with their ACL injury for 20 years with sustained good subjective knee function also seem to have knee cartilage of good quality, with T1Gd values not very different from a healthy reference group.

Changes in MR relaxation times of the meniscus with acute loading: an in vivo pilot study in knee osteoarthritis

PURPOSE

To prospectively evaluate changes in T1ρ and T2 relaxation times in the meniscal body with acute loading using MRI in osteoarthritic knees and to compare these findings with those of age-matched healthy controls.

MATERIALS AND METHODS

Female subjects above 40 years of age with (N1  = 20) and without osteoarthritis (OA) (N2  = 10) were imaged on a 3 Tesla MR scanner using a custom made loading device. MR images were acquired, with the knee flexed at 20°, with and without a compressive load of 50% of the subject's bodyweight. The subjects were categorized based on the radiographic evidence of OA. Three different zones (outer, middle, and inner) of meniscus body were defined (each occupying 1/3rd the width). After adjusting for age and body mass index in the general linear regression model, repeated measures analysis of variance was used to detect significant differences in T1ρ and T2 with and without loading.

RESULTS

In the unloaded condition, the average T1ρ and T2 times were elevated in the outer and middle zones of the medial meniscus in OA subjects compared with the controls. In the loaded condition, T1ρ and T2 times of the outer zone of the medial meniscus was significantly elevated in OA subjects compared with controls. Finally the change (from unloaded to loaded) was significantly higher in controls than OA subjects (15.1% versus 8.3%; P = 0.039 for ΔT1ρ , and 11.5% versus 6.9%, P = 0.049 for ΔT2 ).

CONCLUSION

These findings suggest that while the OA process appears to affect the relaxation times of all regions within the meniscus, it may affect some regions sooner or to a greater degree. Furthermore, the differences in the change in relaxation times between unloaded and loaded conditions may reveal evidence about load transmission failure of the outer zone of the medial meniscus in subjects with knee OA. It is possible that these metrics (ΔT1ρ and ΔT2 ) may be valuable as an early biomechanical biomarker, which could be used to predict load transmission to the underlying articular cartilage.

Free rehabilitation is safe after isolated meniscus repair: a prospective randomized trial comparing free with restricted rehabilitation regimens

BACKGROUND

The optimal rehabilitation program after meniscus repair has not been established. Numerous regimens have been suggested as beneficial for meniscus healing, but no controlled trials exist in the literature.

HYPOTHESIS

The purpose of this prospective randomized trial was to investigate outcome with a free or a restricted rehabilitation regimen after isolated meniscus repair. The hypothesis was that free rehabilitation would result in increased failure of meniscus healing.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

A total of 60 patients were included in this study within 2 to 3 days after meniscus repair. No patients with concomitant ligament reconstruction or cartilage repair surgery were included. Meniscus repair was performed with the all-inside technique; only vertical meniscus lesions close to the capsule were repaired. Patients were randomized to free (n = 32) or restricted (n = 28) rehabilitation. Free rehabilitation consisted of 2 weeks (range of motion [ROM], 0°-90°, no brace) and touch weightbearing, with unrestricted activity and free ROM allowed thereafter. Restricted rehabilitation consisted of 6 weeks of hinged brace use with a gradual increase ROM to 90° and only touch weightbearing during the 6 weeks. Patients were seen for follow-up at 3 months, 1 year, and 2 years. Those patients with joint line pain at the 3-month follow-up underwent MRI scanning to evaluate meniscus healing; a subsequent arthroscopy was performed for final evaluation meniscus healing if the MRI indicated lack of meniscus healing. At follow-up, the Knee Osteoarthritis Outcome Score (KOOS), Tegner function score, pain assessment, and patient satisfaction were used to evaluate outcomes.

RESULTS

Eleven patients were lost to follow-up. Repeat arthroscopy in patients with persistent symptoms demonstrated partial healing or lack of healing in 28% and 36% of patients in the free and the restricted rehabilitation groups, respectively (P = .53, nonsignificant). The KOOS and Tegner function scores were similar between groups at all follow-up times, as was patient satisfaction. Patients who underwent subsequent partial meniscectomy because of meniscus repair failure had lower KOOS score and Tegner function score than did patients without repair failure.

CONCLUSION

Free rehabilitation after meniscus repair is safe and does not entail increased failure rates compared with restricted rehabilitation. Subjective and functional outcomes at 1- and 2-year follow-up were not affected by rehabilitation regimen. Clinical outcomes in patients with repair failure who underwent subsequent partial meniscectomy were poorer than in those with healed meniscus repairs. A concern is the 30% overall lack of healing for patients with isolated meniscus lesions repaired with the all-inside technique.

Ultrasonographic evaluation in symptomatic knee osteoarthritis: clinical and radiological correlation

AIM

To explore the relationship among clinical, radiological and ultrasonographical findings in knee osteoarthritis (OA).

METHOD

Sixty-one patients (122 knees) with knee OA were enrolled. Patients' knees were classified into two groups according to symptom severity. Group I consisted of 61 more symptomatic knees and Group II comprised 61 less symptomatic knees. Subjects were clinically assessed for pain and functional status by using a visual analog scale and the Western Ontario and McMaster Universities Arthritis Index (WOMAC), respectively. Knee radiographs were evaluated by using the Kellgren-Lawrence (K-L) grading system. All knees were also evaluated ultrasonographically for meniscal bulging, distal femoral cartilage thickness, cartilage grading and also for the presence of effusion, Baker's cyst and so on.

RESULTS

Baker's cyst and joint effusion were observed more in Group I when compared with Group II. Positive correlations were found between meniscal bulging and all WOMAC scores (all P < 0.05). K-L grades of the patients were also positively correlated with WOMAC scores (all P < 0.05). Meniscal bulging measurements and K-L grades were positively correlated (P < 0.001). There was a negative correlation between cartilage grades and cartilage thickness measurements (all P < 0.001).

CONCLUSIONS

We found that joint space narrowing seemed to be associated with meniscal bulging. Moreover, increased meniscal bulging and presence of Baker's cyst/joint effusion were associated with worse pain or poorer function.

Transcriptome analysis of injured human meniscus reveals a distinct phenotype of meniscus degeneration with aging

OBJECTIVE

Meniscus tears are associated with a heightened risk of osteoarthritis. This study aimed to advance our understanding of the metabolic state of injured human meniscus at the time of arthroscopic partial meniscectomy through transcriptome-wide analysis of gene expression in relation to the patient's age and degree of cartilage chondrosis.

METHODS

The degree of chondrosis of knee cartilage was recorded at the time of meniscectomy in symptomatic patients without radiographic osteoarthritis. RNA preparations from resected menisci (n = 12) were subjected to transcriptome-wide microarray and QuantiGene Plex analyses. Variations in the relative changes in gene expression with age and chondrosis were analyzed, and integrated biologic processes were investigated computationally.

RESULTS

We identified a set of genes in torn menisci that were differentially expressed with age and chondrosis. There were 866 genes that were differentially regulated (≥1.5-fold difference and P < 0.05) with age and 49 with chondrosis. In older patients, genes associated with cartilage and skeletal development and extracellular matrix synthesis were repressed, while those involved in immune response, inflammation, cell cycle, and cellular proliferation were stimulated. With chondrosis, genes representing cell catabolism (cAMP catabolic process) and tissue and endothelial cell development were repressed, and those involved in T cell differentiation and apoptosis were elevated.

CONCLUSION

Differences in age-related gene expression suggest that in older adults, meniscal cells might dedifferentiate and initiate a proliferative phenotype. Conversely, meniscal cells in younger patients appear to respond to injury, but they maintain the differentiated phenotype. Definitive molecular signatures identified in damaged meniscus could be segregated largely with age and, to a lesser extent, with chondrosis.

Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To identify risk factors for osteoarthritis (OA) of the knee, hip, and ankle, including joint injury, sport, physical activity, overweight/obesity, and occupational activity, in all age groups.

BACKGROUND

OA is a significant health problem worldwide, affecting up to 10% of men and 18% of women over 60 years of age. There has not been a comprehensive review examining modifiable physical risk factors associated with the onset of OA. This evidence is important to inform the physiotherapy management of individuals following onset of OA.

METHODS

Twelve electronic databases were systematically reviewed. The studies selected met the following criteria: (1) original data; (2) joint injury, sport activity, physical activity, overweight/obesity, and/or occupational activity investigated as risk factors; (3) outcomes included OA (hip, knee, and/or ankle); and (4) analytic component of study design. The data extracted included study design, years of follow-up, study population, OA definition, risk factors, and results (effect estimates reported or calculated where available). The quality of evidence was assessed based on a modified version of the Downs and Black checklist.

RESULTS

Joint injury, obesity, and occupational activity were associated with an increased risk of OA of the knee and hip. Sport and physical activity produced inconsistent findings. Joint injury was identified as a significant risk factor for knee OA (combined odds ratio = 3.8; 95% confidence interval: 2.0, 7.2) and hip OA (combined odds ratio = 5.0; 95% confidence interval: 1.4, 18.2), as was previous meniscectomy with or without anterior cruciate ligament injury for knee OA (combined odds ratio = 7.4; 95% confidence interval: 4.0, 13.7). There is a paucity of research examining risk factors associated with ankle OA; this review identified only 2 studies with this outcome.

CONCLUSION

Joint injury, obesity, and occupational activity are associated with an increased risk of knee and hip OA. Some findings remain inconclusive, including levels of physical activity and sport specificity in individuals who do not suffer an injury. Early identification of individuals at risk for OA provides an opportunity for physiotherapy management or other interventions to modify risk-related behavior. There is a need in the literature for additional high-quality studies, such as prospective cohort studies, that minimize potential bias in examining the relationship between physical risk factors and OA.

LEVEL OF EVIDENCE

Prognosis, level 2a-.

The effects of meniscus injury on the development of knee osteoarthritis: data from the osteoarthritis initiative

BACKGROUND

Osteoarthritis (OA) is a leading cause of pain and disability, and the knee is one of the most commonly affected joints. Many have speculated that injury to the meniscus may play a key role in the development of knee OA; however, the exact relationship of meniscus injury and knee OA is unknown.

PURPOSE

To examine the rate of meniscus injuries in patients with and without incident radiographic knee OA and to explore how the type, size, and location of the meniscus injury affects the development of OA.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A secondary case-control analysis was conducted of the Knee Osteoarthritis Initiative (OAI) database, which is a prospective, longitudinal, multicenter cohort study of knee health in patients at risk for knee OA. Eligible patients included those without radiographic OA at baseline in 1 knee. Thirty-two patients who developed radiographic OA in a previously unaffected knee after 2 years of follow-up were matched to 64 age-, sex-, and body mass index-matched patients who did not develop OA. The study analyzed the relationship between the development of OA and the presence of a meniscus tear or degenerative signal, meniscus extrusion, tear type, and size of injury on the baseline magnetic resonance imaging scans. Conditional logistic regression was used to identify significant predictors of OA.

RESULTS

The rate of medial meniscus lesions (tear or degeneration) was not significantly higher in those who developed incident OA (85%) compared with the control patients (68%; P = .07). However, medial meniscus extrusion (odds ratio [OR], 3.03; 95% confidence interval [CI], 1.4-6.5), complex tears (OR, 5.0; 95% CI, 1.0-25), and tears with large radial involvement (OR, 5.92; 95% CI, 1.7-7.5) were more common at baseline in cases compared with controls.

CONCLUSION

Knees with meniscus tears with greater radial involvement and extrusion are at greater risk for later development of radiographic OA.

Relationship between pre-radiographic cartilage damage following anterior cruciate ligament injury and biomarkers of cartilage turnover in clinical practice: a cross-sectional observational study

OBJECTIVE

To determine whether differences in synovial fluid (SF) biomarkers of collagen and proteoglycan turnover are associated with pre-radiographic damage to articular cartilage and menisci following anterior cruciate ligament (ACL) injury and are of clinical value.

METHOD

SF samples from ACL injured knees of 108 patients were obtained when damage to cartilages and menisci was evaluated arthroscopically. Concentrations of SF collagenase-generated cleavage neoepitope of type II collagen (C2C) were determined using ELISA and aggrecan-derived disaccharides of chondroitin-4-sulfate (Δdi-C4S), chondroitin-6-sulfate (Δdi-C6S), and keratan sulfate (KS), were measured in SF by High performance liquid chromatography (HPLC).

RESULTS

Radiographic examination failed to detect any intra-articular degenerative changes. The number of high-grade cartilage lesions was positively associated with age, duration after injury and the level of C2C, and negatively with the level of KS. There was no association between the number of high-grade cartilage and meniscal lesions. Multivariable logistic regression revealed significant associations of increased C2C (adjusted Odds ratio (OR) of the upper quartile to remainder of 2.49, 95% Confidence interval (CI) = 0.85-7.27) and decreased KS (adjusted OR of the lower quartile to the remainder of 3.32, 95% CI = 1.19-9.24) with the presence of three or more high-grade cartilage lesions, independent of age and duration after injury. The combined impact of increased C2C and decreased KS was 22.8 (95% CI = 1.95-265.9), far exceeding the impact of each independent biomarker.

CONCLUSION

Combinations of the C2C and KS as described here may offer greater ability to identify patients with early pre-radiographic high-grade cartilage damage compared to single clinical or biomarker parameters.

Risk factors for meniscal tears: a systematic review including meta-analysis

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To review and critically appraise the literature for factors that increase the risk for meniscal tears.

BACKGROUND

Meniscal tears are an important cause of disability and time lost from work, and are associated with a 4-fold increase in the long-term risk of knee osteoarthritis. Knowledge of the risk factors that lead to meniscal tears can help to correctly diagnose knee injuries and is important to the development of prevention strategies for knee osteoarthritis.

METHODS

A search of the Cochrane Database of Systematic Reviews, MEDLINE, and Embase, from 1950 to January 2012, and a hand search of reference lists of all initially selected studies, without restriction on language or date of publication, were conducted. Prospective, retrospective, and case-control studies that included individuals over 16 years of age, who had no previous meniscal injuries or surgeries, were selected. A meta-analysis for 17 risk factors was performed. Where considerable heterogeneity among studies was present or the data did not provide sufficient information to perform a meta-analysis, a qualitative synthesis was conducted.

RESULTS

Eleven studies, with a total of 7358 participants, were selected for systematic review. Data were available for meta-analysis for 10 of the 11 studies. Qualitative analysis was conducted using data from 3 of the 11 studies. Results showed strong evidence that age (older than 60 years), gender (male), work-related kneeling and squatting, and climbing stairs (greater than 30 flights) were risk factors for degenerative meniscal tears. We also found strong evidence that playing soccer and playing rugby were strong risk factors for acute meniscal tears. Waiting longer than 12 months between the anterior cruciate ligament injury and reconstructive surgery was a strong risk factor for a medial meniscal tear but not for a lateral meniscal tear.

CONCLUSION

The literature indicates a number of risk factors leading to either degenerative or acute meniscal tears, with some of these factors being potentially modifiable.

LEVEL OF EVIDENCE

Prognosis, level 2a.

Augmentation techniques for isolated meniscal tears

Meniscal tears are relatively common injuries sustained by athletes and non-athletes alike and have far reaching functional and financial implications. Studies have clearly demonstrated the important biomechanical role played by the meniscus. Long-term follow-up studies of post-menisectomy patients show a predisposition toward the development of degenerative arthritic changes. As such, substantial efforts have been made by researchers and clinicians to understand the cellular and molecular basis of meniscal healing. Proinflammatory cytokines have been shown to have a catabolic effect on meniscal healing. In vitro and some limited in vivo studies have shown a proliferative and anabolic response to various growth factors. Surgical techniques that have been developed to stimulate a healing response include mechanical abrasion, fibrin clot application, growth factor application, and attempts at meniscal neovascularization. This article discusses various augmentation techniques for meniscal repair and reviews the current literature with regard to fibrin clot, platelet rich plasma, proinflammatory cytokines, and application of growth factors.

Ultrasonographic evaluation of the femoral cartilage thickness after unilateral arthroscopic partial meniscectomy

PURPOSE

To assess the distal femoral cartilage after unilateral arthroscopic partial meniscectomy and to explore the relationship between cartilage thickness and various disease-/surgery-related parameters.

METHODS

Eighty-nine patients (42 M, 47 F) who had undergone arthroscopic partial meniscectomy surgery were evaluated. Ultrasonographic distal femoral cartilage thicknesses were measured with a 5-13-MHz linear probe (General Electric, Logiq P5) on mid-points of the lateral condyle, intercondylar notch and medial condyle of operated and non-operated knees by a physician blinded to patients' data. Demographic features, duration after surgery, type of meniscal tear and site of meniscectomy were recorded.

RESULTS

Mean age of the patients was 51.8 ± 12.8 years (range 18-88). Mean body mass index was 29.4 ± 4.4 kg/m2 (range 18-38). Overall, in patients with degenerative meniscal tears, femoral cartilage thicknesses pertaining to all the three measured sites (lateral, intercondylar and medial) were found to be decreased in the operated knees when compared with those of the non-operated knees (p = 0.004, p = 0.003, p = 0.041, respectively), whereas in patients with non-degenerative tears, this decrease was significant only in the intercondylar area (p = 0.038). When patients were grouped according to the duration (months) after their surgery (≤36, 37-48 and ≥49), cartilage thickness was similar between both knees in the first group, decreased at the lateral condyle (p = 0.008) and intercondylar area (p = 0.049) in the second group and decreased at all three sites (lateral, intercondylar and medial) in the third group (p = 0.015, p = 0.005 and p = 0.008, respectively).

CONCLUSION

These findings would be considered as unfavourable with respect to weight-bearing, and thus, conservative measures to support relevant joints would strongly be kept in mind during clinical practice. Lastly, ultrasonography may be a convenient alternative imaging method for the evaluation of short- and medium-term cartilage loss in patients with arthroscopic partial meniscectomy.

LEVELS OF EVIDENCE

III.

Total meniscectomy in adolescents: a 40-year follow-up

We continued a prospective longitudinal follow-up study of 53 remaining patients who underwent open total meniscectomy as adolescents and who at that time had no other intra-articular pathology of the knee. Their clinical, radiological and patient-reported outcomes are described at a mean follow-up of 40 years (33 to 50). The cohort of patients who had undergone radiological evaluation previously after 30 years were invited for clinical examination, radiological evaluation and review using two patient-reported outcome measures. A total of seven patients (13.2%) had already undergone total knee replacement at the time of follow-up. A significant difference was observed between the operated and non-operated knee in terms of range of movement and osteoarthritis of the tibiofemoral joint, indicating a greater than fourfold relative risk of osteoarthritis at 40 years post-operatively. All patients were symptomatic as defined by the Knee Injury and Osteoarthritis Outcome Score. This study represents the longest follow-up to date and it can be concluded that meniscectomy leads to symptomatic osteoarthritis of the knee later in life, with a resultant 132-fold increase in the rate of total knee replacement in comparison to their geographical and age-matched peers.

Finnish Degenerative Meniscal Lesion Study (FIDELITY): a protocol for a randomised, placebo surgery controlled trial on the efficacy of arthroscopic partial meniscectomy for patients with degenerative meniscus injury with a novel 'RCT within-a-cohort' study design

INTRODUCTION

Arthroscopic partial meniscectomy (APM) to treat degenerative meniscus injury is the most common orthopaedic procedure. However, valid evidence of the efficacy of APM is lacking. Controlling for the placebo effect of any medical intervention is important, but seems particularly pertinent for the assessment of APM, as the symptoms commonly attributed to a degenerative meniscal injury (medial joint line symptoms and perceived disability) are subjective and display considerable fluctuation, and accordingly difficult to gauge objectively.

METHODS AND ANALYSIS

A multicentre, parallel randomised, placebo surgery controlled trial is being carried out to assess the efficacy of APM for patients from 35 to 65 years of age with a degenerative meniscus injury. Patients with degenerative medial meniscus tear and medial joint line symptoms, without clinical or radiographic osteoarthritis of the index knee, were enrolled and then randomly assigned (1 : 1) to either APM or diagnostic arthroscopy (placebo surgery). Patients are followed up for 12 months. According to the prior power calculation, 140 patients were randomised. The two randomised patient groups will be compared at 12 months with intention-to-treat analysis. To safeguard against bias, patients, healthcare providers, data collectors, data analysts, outcome adjudicators and the researchers interpreting the findings will be blind to the patients' interventions (APM/placebo). Primary outcomes are Lysholm knee score (a generic knee instrument), knee pain (using a numerical rating scale), and WOMET score (a disease-specific, health-related quality of life index). The secondary outcome is 15D (a generic quality of life instrument). Further, in one of the five centres recruiting patients for the randomised controlled trial (RCT), all patients scheduled for knee arthroscopy due to a degenerative meniscus injury are prospectively followed up using the same protocol as in the RCT to provide an external validation cohort. In this article, we present and discuss our study design, focusing particularly on the internal and external validity of our trial and the ethics of carrying out a placebo surgery controlled trial.

ETHICS AND DISSEMINATION

The protocol has been approved by the institutional review board of the Pirkanmaa Hospital District and the trial has been duly registered at ClinicalTrials.gov. The findings of this study will be disseminated widely through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT00549172.

Acute injury affects lubricin expression in knee menisci: an immunohistochemical study

The aim of this study was to investigate for the first time lubricin expression in intact menisci and in menisci from patients with recent knee joint injury using histology, immunohistochemistry, Western blotting and gene expression analysis, to provide insights into pathological processes affecting meniscal tissue. Lubricin expression was studied in vivo in 20 patients (14 males and 6 females) with recent joint injury subjected to arthroscopic partial meniscectomy and in vitro in fibroblast-like cells from meniscus tissue to establish whether it is down-regulated following acute traumatic knee injury. The control group consisted of cadaver donors with normal menisci. Histology demonstrated a normal tissue without structural changes in control samples and structural alterations and clefts in injured menisci. Very strong lubricin immunohistochemical staining was observed in intact menisci; in contrast weak staining was seen in injured menisci. Western blot and mRNA expression analysis also demonstrated strong lubricin expression in control cells and a negligible amount of lubricin in injured fibroblast-like cells. Our data provide information concerning the immediate in vivo response to injury of human knee menisci by documenting early changes in the boundary-lubricating ability of synovial fluid and articular cartilage integrity. These findings may provide the biological basis for developing novel medical therapies to be applied before surgical treatment to preserve tissue function and prevent cartilage damage.

Arthroscopic partial meniscectomy in middle-aged patients with mild or no knee osteoarthritis: a protocol for a double-blind, randomized sham-controlled multi-centre trial

BACKGROUND

Arthroscopic partial meniscectomy has been shown to be of no benefit to patients with concomitant knee osteoarthritis, but the optimal treatment of a degenerative meniscus tear in patients with mild or no knee osteoarthritis is unknown. This article describes the rationale and methodology of a randomized sham-controlled trial to assess the benefit of arthroscopic partial meniscectomy of a medial meniscus tear in patients with mild or no knee osteoarthritis. The objective of the study is to test whether the benefit from arthroscopic partial meniscectomy in patients with knee pain, medial meniscus lesion and mild/no knee osteoarthritis, is greater after arthroscopic partial meniscectomy than following sham surgery.

METHODS

We will conduct a randomized controlled trial of treatment for degenerative meniscus tears in middle-aged patients (aged 35-55 years) with an MRI-verified medial meniscus lesion and mild or no knee radiographic osteoarthritis (grade 0-2 on the Kellgren & Lawrence scale). Patients will be randomized to receive either conventional arthroscopic partial meniscectomy or a sham surgery procedure. The primary outcome will be the KOOS5 derived from the 'Knee Injury and Osteoarthritis Outcome Score' at 2 years follow-up. Secondary outcomes at 2 years will include all five individual subscales of the KOOS, a global perceived effect score, the Short-Form-36 health status score, EQ-5D for economic appraisal and objective tests of muscle strength and physical function. Radiographic knee osteoarthritis will be evaluated at 5 years.

DISCUSSION

Demonstration of no additional benefit from arthroscopic partial meniscectomy on pain and function should lead to a change in clinical care of patients with a degenerative meniscus tear. The results of this study will provide empirical evidence for the potential benefit/harm of arthroscopic partial meniscectomy compared to a masked sham-therapeutics intervention.

Two-year follow-up study on clinical and radiological outcomes of polyurethane meniscal scaffolds

BACKGROUND

Little is known about radial displacement (RD) of polyurethane (PU) scaffolds, intended for partial meniscus defect substitution; no data are available on whether rim thickness influences RD and whether RD correlates with clinical outcome scores.

HYPOTHESES

The meniscus is not extruded preoperatively, but RD occurs after scaffold implantation. A thicker rim will limit RD, and there is no correlation between RD and clinical outcome.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-six patients were implanted with a PU scaffold (8 lateral, 18 medial). Radial displacement (mm) was evaluated on magnetic resonance images preoperatively and at 3 months, 1 year, and 2 years postoperatively. At each time point, it was determined whether a correlation existed between the rim and RD. Clinical outcome was determined using a visual analog scale (VAS) for pain as well as the Lysholm knee scoring scale, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) score.

RESULTS

Radial displacement of lateral scaffolds was not significantly different (P = .178) either preoperatively (mean ± SD, 3.42 ± 0.99 mm) or at 3 months (4.82 ± 0.59 mm), 1 year (4.55 ± 0.87 mm), or 2 years postoperatively (4.10 ± 0.93 mm). No correlation was observed between the rim and lateral RD at all time points. Medial scaffold RD increased significantly (P < .001) from preoperative values (2.17 ± 0.84 mm) to those at 3 months (4.25 ± 0.89 mm), 1 year (4.43 ± 1.01 mm), and 2 years postoperatively (4.41 ± 0.96 mm). A strong negative correlation between medial RD and the rim was observed at all time points. There was no significant correlation between clinical outcome scores and RD, either preoperatively or postoperatively.

CONCLUSION

This study demonstrated that limited medial meniscal RD was present preoperatively but increased by 2 mm after scaffold implantation. Lateral RD was also present preoperatively but did not increase after scaffold implantation. Importantly, a strong negative correlation was found between the rim and postoperative medial RD; a thicker rim limited RD. However, in the lateral compartment, rim thickness did not correlate with RD because RD was already strongly present preoperatively. Finally, no correlations were observed between scaffold RD and clinical outcome scores, either preoperatively or postoperatively.

The effect of anterior cruciate ligament reconstruction on the progression of osteoarthritis

Anterior cruciate ligament rupture (ACL) is a common injury, particularly among young sporting adults. Early onset osteoarthritis (OA) can be a devastating and difficult to manage consequence of such an injury. The techniques for reconstructing the ACL are advancing all the time, but the effect that this has on the progression of OA is less well understood. Many factors affect the development of OA following an ACL injury, including direct and indirect trauma to the articular cartilage, associated meniscal injuries, chronic tibiofemoral joint instability, and multiple enzymatic pathways. This review will summarize the current evidence surrounding each of these areas, and describe some of the recent developments that may have an impact on the management of these injuries in the future.

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX', a randomised control trial protocol

Background

Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy.

Methods/design

62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters.

Discussion

The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease.

Trial Registration

Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897

Neuromuscular function during a forward lunge in meniscectomized patients

OBJECTIVE

This study aimed to investigate differences in knee joint kinematics, ground reaction force kinetics and neuromuscular activity including muscle coactivation, and medial versus lateral muscle activity during a forward lunge between the operated and contralateral legs of meniscectomized patients. Such differences may represent early changes in neuromuscular function potentially contributing to the development of knee osteoarthritis.

METHODS

Twenty-two unilaterally meniscectomized patients (15 men and 7 women; age = 45.4 ± 5.1 yr, height = 174.3 ± 7.1 cm, weight = 77.3 ± 15.4 kg (mean ± SD)) were investigated on their operated and contralateral legs during a forward lunge using synchronous goniometer, force plate, and EMG recording (vastus lateralis, vastus medialis, biceps femoris, and semitendinosus).

RESULTS

During impact loading, an increased level of muscle coactivation (38.0% (29.8%-46.3%) vs 30.1% (23.6%-36.6%), P = 0.02; mean (95% confidence interval)), reduced range of motion (59.4° (54.5°-64.2°) vs 64.9 (60.8°-70.0°), P = 0.01), and increased loading rate (985% BW·s(-1) (653-1317% BW·s(-1)) vs 696% BW·s(-1) (525-868% BW·s(-1)), P = 0.01) were observed in the operated leg compared with the contralateral leg. In addition, different patterns of medial versus lateral neuromuscular activity were observed in the operated and contralateral legs, along with minor differences during the other phases of the forward lunge.

CONCLUSIONS

The findings of increased muscle coactivation, reduced range of motion, and increased loading rate in the operated compared with the contralateral leg support the hypothesis that meniscectomized patients demonstrate modulations in kinetics, kinematics, and neuromuscular activity, which may represent early changes in neuromuscular function that precede and affect development of knee osteoarthritis. The results also indicate that the forward lunge test is a sensitive measure to identify leg-to-leg differences in neuromuscular function after surgical interventions.

A 12-week exercise therapy program in middle-aged patients with degenerative meniscus tears: a case series with 1-year follow-up

STUDY DESIGN

Case series.

BACKGROUND

Exercise is a viable treatment alternative to arthroscopic partial meniscectomy in patients with degenerative meniscus tears. No study has reported in detail the type of exercises, progression, tolerance, and potential benefit from an exercise therapy program in these patients who have not had surgery. This case report describes a progressive exercise therapy program aimed at improving neuromuscular function and muscle strength in middle-aged patients with degenerative meniscus tears, the outcome over a 12-week period, and the ability to maintain improvements up to 1 year.

CASE DESCRIPTION

The first 20 patients (age range, 38-58 years) included in an ongoing randomized controlled trial.

OUTCOMES

Outcomes data included the Knee injury and Osteoarthritis Outcome Score, a 7-point global rating of change scale, isokinetic knee muscle strength tests, and 3 lower extremity performance tests. Postintervention, 16 of 20 patients showed clinically meaningful changes (greater than 10 points) on the Knee injury and Osteoarthritis Outcome Score knee-related quality of life subscale, 19 of 20 patients rated themselves as "a lot better" or "better" on the global rating of change scale, all patients had increased quadriceps muscle strength, and the majority of patients improved on the lower extremity performance tests. At 1 year postintervention, the majority of patients had maintained the improvements and none of the patients had undergone surgery.

DISCUSSION

The described neuromuscular- and strength-training program should be considered for rehabilitation of middle-aged individuals with degenerative meniscus tears. However, head-to-head comparison of programs in a randomized design is needed to determine if this specific program is significantly better than other interventions.

Synthetic meniscus replacement: a review

The number of meniscus-related operations continues to rise due to the ageing and more active population. Irreparable meniscal lesions generally require (partial) meniscectomy. Although a majority of the patients benefit from pain relief and functional improvement post-meniscectomy, some remain symptomatic. As an alternative to a meniscal allograft, which is only indicated for the severely damaged meniscus, most patients can nowadays be treated by implantation of a synthetic meniscal substitute. Currently three of these implants, two partial and one total replacement, are clinically available and several others are in the stage of preclinical testing. Grossly, two types of meniscal substitutes can be distinguished: porous, resorbable implants that stimulate tissue regeneration and solid, non-resorbable implants that permanently replace the whole meniscus. Although the implantation of a porous meniscus replacement generally seems promising and improves clinical outcome measures to some degree, their superiority to partial meniscectomy still needs to be proven. The evaluation of new prostheses being developed requires a wider focus than has been adopted so far. Upon selection of the appropriate materials, preclinical evaluation of such implants should comprise a combination of (in vitro) biomechanical and (in vivo) biological tests, while up to now the focus has mainly been on biological aspects. Obviously, well-defined randomised controlled trials are necessary to support clinical performance of new implants. Since the use of a meniscus replacement requires an additional costly implant and surgery compared to meniscectomy only, the clinical outcome of new products should be proven to surpass the results of the conventional therapies available.

Cell study of the three areas of the meniscus: effect of growth factors in an experimental model in sheep

Meniscus had two areas with different vascular supply. Cells of the two areas and the synovium were monolayer cultivated. We analyzed the expression of genes of Col1, Col 2A, MMP-2, MMP-13, and aggrecan in a baseline state and after incubation with VEGF, TGF-β, FGF, and IGF. We found that the growth factors used produced a major increase in the MMP-13 in all three areas. In the vascular area, the stimulation of MMP-3 was produced by FGF, while in the synovial and avascular areas, it was caused by TGF-β. MMP-2 was only stimulated in the synovial area by IGF. Col 2A was stimulated in the synovial area by VEGF, and in the avascular area by TGF-β, FGF, and IGF, whereas Col 1 was stimulated in the avascular area by IGF, FGF, and VEGF. The vascular or avascular areas of the meniscus, behave differently in terms of repair, and their cells express different factors. The growth factors act in a different way in each meniscal area.

The Relationship between Meniscal Tears and Meniscal Position

OBJECTIVE

To investigate how different types of meniscal tears predispose to different patterns of meniscal position in subjects with and without symptomatic knee osteoarthritis (OA).

METHODS

A cross-sectional analysis of 161 women participating in an observational study to evaluate knee OA progression was performed using baseline MRI data. Meniscal morphologic features were scored in three separate locations. Meniscal position measures were determined for extrusion and proportion of coverage. Analysis was performed using multiple linear regression models treating each tear type as an individual variable with a binary response.

RESULTS

Complex tears, cysts and maceration of the medial meniscus were associated with more medial (p=0.0004, p=0.004, p <0.0001, respectively) and anterior extrusion (p =0.03, p=0.03, p<0.0001, respectively) than normal menisci. Horizontal tears of the lateral meniscus had more lateral (p=0.005) and anterior extrusion (p<0.0001) than normal menisci. Anterior and body tears of the medial meniscus were associated with more anterior extrusion (p=0.0006, p=0.01, respectively), whereas meniscal body tears alone had more medial extrusion than normal menisci (p= 0.0002). Meniscal body tears of the lateral meniscus had more lateral extrusion than normal menisci (p=0.01).

CONCLUSION

Anterior horn and meniscal body tears and the more severe macerated and complex tear types predisposed to more medial meniscal extrusion. Laterally, only meniscal body and horizontal tears significantly affected extrusion, potentially reflecting a lower overall prevalence of lateral meniscal tears. These results may have important implications in identifying tear types associated with more meniscal dysfunction, with the ultimate goal of identifying those at greatest risk for knee OA progression.

Medial meniscus tear morphology and chondral degeneration of the knee: is there a relationship?

PURPOSE

The purpose of this study was to examine the association of medial meniscus tear morphology with the pathogenesis of articular cartilage degeneration.

METHODS

From May 2006 to December 2007, we prospectively evaluated 103 patients diagnosed with an isolated medial meniscus tear. Meniscus tear morphology and location, cartilage degeneration according to the Noyes score, and covariates including age, body mass index, gender, and injury date were documented. The relationship between severity of articular cartilage degeneration and meniscus tear morphology was analyzed by analysis of variance. Regression analysis was used to analyze predictors of severity of cartilage lesions.

RESULTS

Analysis of variance showed significant differences in the severity of articular cartilage lesions based on medial meniscus tear morphology (P < .05). Compared with bucket-handle/vertical tears, root and radial/flap tears were associated with significantly greater degeneration on the medial femoral condyle; root and complex tears were associated with significantly greater degeneration on the medial tibial plateau; and radial/flap tears were associated with significantly greater degeneration on the lateral tibial plateau. Age and gender were significant predictors of the Noyes medial-compartment score, and age, body mass index, and meniscus tear morphology were significant predictors of the Noyes lateral-compartment score.

CONCLUSIONS

Meniscus tears with increasing disruption of the circumferential meniscal fibers were significantly associated with cartilage lesions of increasing severity in both the medial and lateral compartments of the knee.

LEVEL OF EVIDENCE

Level IV, prognostic case series.

Prediction of progression of radiographic knee osteoarthritis using tibial trabecular bone texture

OBJECTIVE

To develop a system for predicting the progression of radiographic knee osteoarthritis (OA) using tibial trabecular bone texture.

METHODS

We studied 203 knees with (n = 68) or without (n = 135) radiographic tibiofemoral OA in 105 subjects (90 men and 15 women with a mean age of 54 years) in whom 2 sets of knee radiographs were obtained 4 years apart. We determined medial and lateral compartment tibial trabecular bone texture using an automated region selection method. Three texture parameters were calculated: roughness, degree of anisotropy, and direction of anisotropy based on a signature dissimilarity measure method. We evaluated tibiofemoral OA progression using a radiographic semiquantitative outcome: an increase in the medial joint space narrowing (JSN) grade. We examined the predictive ability of trabecular bone texture in knees with and those without preexisting radiographic OA, with adjustment for age, sex, and body mass index, using logistic regression (generalized estimating equations) and receiver operating characteristic curves.

RESULTS

The prediction of increased medial JSN in knees with or without preexisting radiographic OA was the most accurate for medial trabecular bone texture; the area under the curve (AUC) was 0.77 and 0.75, respectively. For lateral trabecular bone texture, the AUC was 0.71 in knees with preexisting OA and 0.72 in knees without preexisting OA.

CONCLUSION

We have developed a system, based on analyzing tibial trabecular bone texture, which yields good prediction of loss of tibiofemoral joint space. The predictive ability of the system needs to be further validated.

Muscle strength and functional performance in patients at high risk of knee osteoarthritis: a follow-up study

PURPOSE

To investigate whether changes from 2 to 4 years post arthroscopic partial meniscectomy (APM) in mechanical muscle function and objectively measured function differ between the operated and contra-lateral leg of APM patients or compared with controls.

METHODS

Twenty-two patients (age 46.6 ± 5.0, BMI 24.7 ± 2.9) and 25 controls (age 46.4 ± 5.2, BMI 25.1 ± 4.6) previously examined at ~2 years post APM were examined again at ~4 years post surgery for maximal knee extensor/flexor voluntary contraction (MVC) and rapid force capacity. Functional performance was assessed by the distance achieved during a one-leg hop test and the maximum number of knee bends performed in 30 s. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to evaluate self-reported outcomes.

RESULTS

Overall changes from 2 to 4 years post APM did not differ in maximal muscle strength, rapid force capacity, and functional performance between the operated and contra-lateral leg of patients or control legs. However, secondary analysis showed a difference in change in knee extensor MVC resulting in a 6% difference between the operated and contra-lateral leg of patients at follow-up.

CONCLUSIONS

No differences in longitudinal changes were observed from 2 to 4 years post APM between patients and controls. The secondary finding of differential changes over time in knee extensor MVC between the operated and contra-lateral leg partly confirm our hypothesis that differences in muscle strength may evolve from 2 to 4 years post APM. This differential change may represent an initial sign of an evolving lower limb muscle asymmetry, which may play a role in the development of knee OA.

LEVEL OF EVIDENCE

III.

Factors associated with meniscal extrusion in knees with or at risk for osteoarthritis: the Multicenter Osteoarthritis study

PURPOSE

To assess the associations of meniscal tears, knee mal-alignment, cartilage damage, knee effusion, and body mass index with meniscal extrusion.

MATERIALS AND METHODS

The Multicenter Osteoarthritis study is an observational study of individuals who have or are at risk for knee osteoarthritis (OA). The HIPAA-compliant protocol was approved by the institutional review boards of all participating centers, and written informed consent was obtained from all patients. All subjects with available baseline knee radiographs and magnetic resonance (MR) images were included. MR imaging assessment of meniscal morphologic characteristics, meniscal position, and cartilage morphologic characteristics with use of the Whole-Organ Magnetic Resonance Imaging Score system was performed by two musculoskeletal radiologists. Cross-sectional associations of severity of meniscal tears, knee malalignment, tibiofemoral cartilage damage, knee effusion, and body mass index with meniscal extrusion were assessed by using logistic regression, with multiadjustments when testing each predictor.

RESULTS

A total of 1527 subjects (2131 knees; 2116 medial and 2106 lateral menisci) were included. Medially, meniscal tears, varus malalignment, and cartilage damage were associated with meniscal extrusion, with odds ratios (ORs) of 6.3 (95% confidence interval [CI]: 5.0, 8.0), 1.3 (95% CI: 1.1, 1.7), and 1.8 (95% CI: 1.4, 2.2), respectively. Laterally, meniscal tears, valgus malalignment, and cartilage damage were associated with meniscal extrusion, with ORs of 10.3 (95% CI: 7.1, 14.9), 2.2 (95% CI: 1.5, 3.2), and 2.0 (95% CI: 1.3, 2.9), respectively.

CONCLUSION

Meniscal tears are not the only factors associated with meniscal extrusion; other factors include knee malalignment and cartilage damage. Meniscal extrusion is probably an effect of the complex interactions among joint tissues and mechanical stresses involved in the OA process.

The association between changes in synovial fluid levels of ARGS-aggrecan fragments, progression of radiographic osteoarthritis and self-reported outcomes: a cohort study

OBJECTIVE

To investigate whether change in concentrations over time of aggrecanase generated ARGS-aggrecan in synovial fluid (SF ARGS) associates with progression of radiographic knee osteoarthritis (OA) and patient-reported outcome in subjects with previous meniscectomy.

METHODS

We studied 141 subjects at two time points after meniscectomy. Time point A was on average 18 years after meniscectomy, time point B was on average 7.5 years later; 74 subjects had SF available from both examinations. We measured SF ARGS by an electrochemiluminescence immunoassay, graded radiographic features of tibiofemoral or patellofemoral OA according to the Osteoarthritis Research Society International (OARSI) atlas, and scored patient-reported outcomes using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Using logistic regression (adjusted for age, gender, body mass index, time between examinations, and SF ARGS at first examination) we assessed associations between change in SF ARGS between first and second examinations and progression of radiographic OA and KOOS.

RESULTS

In subjects with decreasing SF ARGS between examinations, the likelihood of loss of joint space and worsening of KOOS pain between examinations was increased 6- and 4-fold respectively compared to those increasing in SF ARGS (odds ratio (OR) 5.72; 95% confidence interval (CI) 1.53-21.4 and 3.66; 1.01-13.2, respectively). No significant associations were seen between decreasing SF ARGS and progression of osteophytes (OR 0.88; 0.28-2.78), or for patient-reported outcomes other than KOOS pain.

CONCLUSION

Having decreasing levels of SF ARGS over time was associated with an increased risk of loss of joint space and pain worsening, but showed no association with other patient-reported outcomes or osteophyte progression.

Patellofemoral and tibiofemoral articular cartilage and subchondral bone health following arthroscopic partial medial meniscectomy

PURPOSE

To examine articular cartilage and subchondral bone changes in tibiofemoral and patellofemoral joints following partial medial meniscectomy.

METHODS

For this cross-sectional study, 158 patients aged 30-55 years, without evidence of knee osteoarthritis at arthroscopic partial medial meniscectomy (APMM), and 38 controls were recruited. MRI was performed once on the operated knee for each subcohort of 3 months, 2 or 4 years post-surgery, and the randomly assigned knee of the controls. Cartilage volume, cartilage defects, and bone size were assessed using validated methods.

RESULTS

Compared with controls, APMM patients had more prevalent cartilage defects in medial tibiofemoral (OR = 3.17, 95%CI 1.24-8.11) and patellofemoral (OR = 13.76, 95%CI 1.52-124.80) compartments, and increased medial tibial plateau bone area (B = 143.8, 95%CI 57.4-230.2). Time from APMM was positively associated with cartilage defect prevalence in medial tibiofemoral (OR = 1.02, 95%CI 1.00-1.03) and patellofemoral (OR = 1.04, 95%CI 1.01-1.07) compartments, and medial tibial plateau area (B = 2.5, 95%CI 0.8-4.3), but negatively associated with lateral tibial cartilage volume (B = -4.9, 95%CI -8.4 to -1.5). The association of APMM and time from APMM with patellar cartilage defects was independent of tibial cartilage volume.

CONCLUSIONS

Partial medial meniscectomy is associated with adverse effects on articular cartilage and subchondral bone, which are associated with subsequent osteoarthritis, in both tibiofemoral and patellofemoral compartments.

LEVEL OF EVIDENCE

III.

Simulation of Anterior Cruciate Ligament Deficiency in a Musculoskeletal Model with Anatomical Knees

Abnormal knee kinematics and meniscus injury resulting from anterior cruciate ligament (ACL) deficiency are often implicated in joint degeneration even though changes in tibio-femoral contact location after injury are small, typically only a few millimeters. Ligament reconstruction surgery does not significantly reduce the incidence of early onset osteoarthritis. Increased knowledge of knee contact mechanics would increase our understanding of the effects of ACL injury and help guide ACL reconstruction methods. Presented here is a cadaver specific computational knee model combined with a body-level musculoskeletal model from a subject of similar height and weight as the cadaver donor. The knee model was developed in the multi-body framework and includes representation of the menisci. Experimental body-level measurements provided input to the musculoskeletal model. The location of tibio-menisco-femoral contact as well as contact pressures were compared for models with an intact ACL, partial ACL transection (posterolateral bundle transection), and full ACL transection during a muscle driven forward dynamics simulation of a dual limb squat. During the squat, small changes in femur motion relative to the tibia for both partial and full ACL transection push the lateral meniscus in the posterior direction at extension. The central-anterior region of the lateral meniscus then becomes “wedged” between the tibia and femur during knee flexion. This “wedging” effect does not occur for the intact knee. Peak contact pressure and contact locations are similar for the partial tear and complete ACL transection during the deep flexion portion of the squat, particularly on the lateral side. The tibio-femoral contact location on the tibia plateau shifts slightly to the posterior and lateral direction with ACL transection.