Meniscal Resection Research Articles

Meniscus—Friend or foe: Epidemiologic observations and surgical implications

Meniscus—Friend or foe: Epidemiologic observations and surgical implications

Current Concepts in Meniscus Tissue Engineering

After partial or total meniscus resection, cartilage degeneration can be observed in many knee joints, frequently culminating in osteoarthritic changes. Therefore, a meniscus preserving therapy should be performed whenever possible. However, despite improved surgical techniques and new treatment strategies, meniscal tissue resection cannot always be avoided. Currently, only few treatment options are available after total meniscectomy, a dissatisfying situation considering that many patients presenting with meniscal injuries are young patients. Transplantation of allogenous menisci has been valuable only in particular cases and does not seem to prevent degenerative changes in the affected knee joint. Because of the unsatisfactory clinical progression after resection of meniscal tissue, new tissue engineering concepts are eagerly sought after. A first step towards a meniscus replacement therapy has been achieved with the development of a collagen meniscus implant (CMI), which has recently been approved for clinical application in Europe. This review will give a short overview about actual meniscus replacement therapies. Current experimental research concepts for meniscus tissue engineering and new perspectives for clinical treatment strategies will also be presented. Additionally, we will report about successful experimental application of new scaffolds and scaffolding materials, the use of different cell types and gene therapy approaches.

Magnetic force-assisted meniscal resection under arthroscopy

Arthroscopic meniscectomy has become a standard procedure for a complete discoid meniscus or for displacement of a meniscal bucket handle tear, although it is not always easy due to poor visualization of the cutting portion. The purpose of this study is to examine whether meniscal resection can be easily carried out in a swine model using the magnetic force-assisted procedure, whereby a metal clip is attached to the meniscal flap and moved by an external magnetic force. Four fresh-frozen porcine lower extremities were used (age range: about 6 months). After opening the knee joint, a flap tear in the medial and lateral menisci was created. Then a metal clip was attached to the edge of the tear. With 20 cm distance between the knee and the disk of the external magnetic device, the flap was observed under arthroscopy. At the highest magnitude of 0.6 T, the direction of the magnetic field was changed. As the direction of the magnetic field was changed to move laterally, medially, up, and down, so the edge of the meniscal flap was observed to move in corresponding directions. Thanks to now having a clear view of the cutting portion, it was evident that meniscal resection could be easily carried out. Although we need to develop special instruments such as Titanium scissors and forceps and an external magnet system for surgery, the current study may be the first step towards a new era in the field of magnet-assisted arthroscopy.

Evaluation of postoperative menisci with MR arthrography and routine conventional MRI

The diagnosis of a recurrent tear can be more difficult in the postoperative meniscus. The purpose of our study was to determine the accuracy of conventional magnetic resonance imaging (MRI) and MRI with intraarticular contrast material [magnetic resonance (MR) arthrography] for detecting recurrent meniscal tears after surgery. Seventy-two patients who had arthroscopic surgery for meniscal tear and still got complaints were selected prospectively for MR arthrography and conventional MRI. Routine knee protocols with appropriate surface coil were used on 0.5 T MRI system. A 1:100 gadolinium-saline solution 30-40 ml was injected intraarticulary for MR arthrography. Of 72 patients, 45 had repeated arthroscopy for comparison of the results. The morphology of the meniscus as seen on MR images was characterized according to meniscal repair an the degree of meniscal resection into three groups. (1) less than 25% of the meniscal resection, (2) more than 25% meniscal resection, (3) meniscal repair. With routine conventional MR images, we grouped patients according to the signal intensity of menisci as Grade 1, Grade 2, Grade 3, and tear. The prevalence of recurrent meniscal tears in our study group was [68% (37/72 tears)]. In the diagnosis of recurrent meniscal tear, conventional MRI and MR arthrography had sensitivities of 54.0% and 94.5%, respectively; specificities of 75.0% and 87.5%, respectively; and accuracy of 57.7% and 93.4%, respectively. The accuracy of the conventional MRI studies was significantly less than that of the MR arthrography group (P<.05). Our study results indicate high overall accuracy for MR arthrography in the diagnosis of recurrent or residual meniscal tears. When meniscal resection is minimal, the right diagnosis could be obtained with conventional MRI. MR arthrography is necessary for patients with meniscal resection of more than 25% and who do not have sufficient joint effusion.

Predictors of Short-term Recovery Differ From Those of Long-term Outcome After Arthroscopic Partial Meniscectomy

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. 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. 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). 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 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).

Intra-articular injection of interleukin-4 decreases nitric oxide production by chondrocytes and ameliorates subsequent destruction of cartilage in instability-induced osteoarthritis in rat knee joints

To investigate the in vitro and in vivo effects of interleukin (IL)-4 on mechanical stress-induced nitric oxide (NO) expression by chondrocytes, and destruction of cartilage and NO production in an instability-induced osteoarthritis (OA) model in rat knee joints, respectively. Cyclic tensile stress (CTS; 0.5Hz and 7% elongation) was applied to cultured normal rat chondrocytes with or without pre-incubation with recombinant rat IL-4 (rrIL-4). Inducible NO synthase (iNOS) mRNA expression and NO production were examined with real-time polymerase chain reaction and the Griess reaction, respectively. OA was induced in rat knee joints by transection of the anterior cruciate and medial collateral ligaments and resection of the medial meniscus. rrIL-4 (10, 50, and 100 ng/joint/day) was injected intra-articularly, and knee joint samples were collected 2, 4, and 6 weeks after surgery. Cartilage destruction was evaluated by the modified Mankin score and Osteoarthritis Research Society International scoring system on paraffin-embedded sections stained with safranin O. Cleavage of aggrecan and NO production were examined by immunohistochemistry for aggrecan neoepitope (NITEGE) and of nitrotyrosine (NT), respectively. rrIL-4 down-regulated CTS-induced iNOS mRNA expression and NO production by chondrocytes. The intra-articular injection of rrIL-4 gave rise to a limited, but significant amelioration of cartilage destruction, prevention of loss of aggrecan, and decrease in the number of NT-positive chondrocytes, an effect that was not dose-dependent. The present study suggests that IL-4 may exert chondroprotective properties against mechanical stress-induced cartilage destruction, at least in part, by inhibiting NO production by chondrocytes.

Water‐soluble C60 fullerene prevents degeneration of articular cartilage in osteoarthritis via down‐regulation of chondrocyte catabolic activity and inhibition of cartilage degeneration during disease development

Studies have shown the roles of oxidative stress in the pathogenesis of osteoarthritis (OA) and induction of chondrocyte senescence during OA progression. The aim of this study was to examine the potential of a strong free-radical scavenger, water-soluble fullerene (C60), as a protective agent against catabolic stress-induced degeneration of articular cartilage in OA, both in vitro and in vivo. In the presence or absence of C60 (100 microM), human chondrocytes were incubated with interleukin-1beta (10 ng/ml) or H2O2 (100 microM), and chondrocyte activity was analyzed. An animal model of OA was produced in rabbits by resection of the medial meniscus and medial collateral ligament. Rabbits were divided into 5 subgroups: sham operation or treatment with C60 at 0.1 microM, 1 microM, 10 microM, or 40 microM. The left knee joint was injected intraarticularly with water-soluble C60 (2 ml), while, as a control, the right knee joint received 50% polyethylene glycol (2 ml), once weekly for 4 weeks or 8 weeks. Knee bone and cartilage tissue were prepared for histologic analysis. In addition, in the OA rabbit model, the effect of C60 (10 microM) on degeneration of articular cartilage was compared with that of sodium hyaluronate (HA) (5 mg/ml). C60 (100 microM) inhibited the catabolic stress-induced production of matrix-degrading enzymes (matrix metalloproteinases 1, 3, and 13), down-regulation of matrix production, and apoptosis and premature senescence in human chondrocytes in vitro. In rabbits with OA, treatment with water-soluble C60 significantly reduced articular cartilage degeneration, whereas control knee joints showed progression of cartilage degeneration with time. This inhibitory effect was dose dependent, and was superior to that of HA. Combined treatment with C60 and HA yielded a significant reduction in cartilage degeneration compared with either treatment alone. The results indicate that C60 fullerene is a potential therapeutic agent for the protection of articular cartilage against progression of OA.

Meniscal ossicle: A case report

Meniscal ossicle is a cortical or cancellous tissue with central viable marrow surrounded by meniscal cartilage. We present a case of medial meniscal ossicle at its posterior horn. A 21-year-old male military recruit visited our clinic due to left knee discomfort. He had not undergone any notable injury on the knee, but complained of intermittent catching or giving way without locking. Simple radiographs showed a small round bony fragment at posteromedial side of knee joint. The magnetic resonance imaging revealed an intra-substance lesion of meniscus, whose signal is identical to bone. On arthroscopy, the articular cartilage of medial femoral condyle and tibial plateau appeared degenerative with a groove-like scar. The medial meniscus seemed swollen at the posterior horn, but there was no discernible tear in the adjacent meniscus. After piecemeal removal of meniscal substance, a small osseous fragment was identified, which was evacuated via posteromedial portal. The resection of meniscus amounted to a subtotal meniscectomy. The activities of daily living were possible without any trouble even after 9 months of follow-up. This entity should be distinguished from intra-articular loose body, and included in the differential diagnosis of the incidental findings of small ossified density around knee joint.

Le kyste méniscal médial intra-articulaire : à propos de cinq cas

The intraarticular medial meniscal cyst is a rare pathology, very little described in the medical literature. This pathology is often discovered fortuitously by the development of the imagery in particular by magnetic resonance. Its physiopathology is not still perfectly known. The authors report five observations of intra articular medial meniscal cyst treated by arthroscopy allowing the meniscal resection with evacuation of the contents of the cyst. The evolution was considered good in all the cases with a complete functional recovery.

Replacement of the Meniscus with a Collagen Implant (CMI).

Replacement of an almost completely absent medial meniscus with a collagen implant (CMI), reconstruction of form and function of the medial meniscus, delay of the development of arthrosis deformans. Subtotal degenerative or traumatic loss of the medial meniscus, stable meniscal periphery, stable anterior and posterior meniscal insertions, joint with stable ligaments. Complete loss of the medial meniscus. Untreated knee ligament instability. Extreme varus deformity. Extensive cartilaginous damage, i.e., levels IV and VI as described by Bauer and Jackson. Advanced unicompartmental or generalized arthrosis. Replacement of the lateral meniscus. Standard anterior arthroscopy portals. Resection of the medial meniscus leaving a complete and stable outer rim. Revitalization of the periphery to promote healing. Measurement of defect size. Insertion and fixation of the CMI with nonresorbable suture material in inside-out technique. Postoperative knee brace with limited motion in extension/flexion of 0/0/60° until week 4, 0/0/90° until week 6. Coutinuous passive motion within the limits of motion from the 1st postoperative day, actively assisted physiotherapy. No weight bearing for 6 weeks, then increased weight bearing for 2 weeks until full weight bearing is achieved. Cycling can commence from 3 months postoperatively. Full sporting activity after 6 months. 60 patients (19-68 years, average 41.6 years) with subtotal loss of the medial meniscus and varus morphotype were treated from January 2001 to May 2004 as part of a prospective, randomized, arthroscopically controlled study. The sample consisted of 30 patients with high tibial valgus osteotomy combined with implantation of a CMI, and 30 patients with valgization correction osteotomy only. The CMI had to be removed from one patient because of a dislocation. Evaluation on the Lysholm Score, IKDC (International Knee Documentation Committee), and subjective pain data revealed only slight, nonsignificant differences for 39 patients after 24 months (CMI and correction n = 23; correction only n = 16). The chondroprotective effect of the CMI in the long term remains to be seen.

Arthroscopic Anterior Cruciate Ligament Reconstruction Using a Hamstring Graft with Interference Screw Fixation

This study assessed the clinical and radiographic results 3 to 8 years after an arthroscopic ACL reconstruction using a hamstring graft with interference screw fixation on femoral and tibial sites. Seventy-six of 100 patients, who underwent an arthroscopic ACL reconstruction, could be re-examined with a mean follow-up of 5 years. The mean Tegner activity score was 4 (scale: 0 to 10) before surgery, and 5 at the follow-up. Fifty-four patients (78%) achieved a satisfactory result in the IKDC rating. The mean Lysholm score was 85 (scale: 0 to 100), the score being better in patients without meniscal resection than those with (P = 0.04). The mean side-to-side difference in anterior-posterior knee laxity was 1.8 mm, and 62 patients (90%) had good stability. Sixty-four patients (93%) had normal range of motion of the knee. Twelve patients (46%) with meniscal resection had osteoarthritic changes, compared with only 8 of those (20%) without meniscal resection (P = 0.03). This medium-term follow-up study showed that good stability and function and normal range of motion of the knee can be achieved in majority of the patients who have undergone an ACL reconstruction with a hamstring graft and interference screw fixation.

Purely Intra-articular Versus General Anesthesia for Proposed Arthroscopic Partial Meniscectomy of the Knee: A Randomized Controlled Trial

The aim of this study was to compare intra-articular anesthesia alone versus general anesthesia with regard to ease of the procedure, level of postoperative pain, and patient satisfaction when partial meniscectomy is anticipated. We prospectively randomized to general anesthesia or to intra-articular anesthesia 107 patients who were about to undergo knee arthroscopy, in whom partial meniscal resection was anticipated on the basis of clinical or radiologic grounds. Technical difficulty of the procedure, level of postoperative pain and nausea, and overall patient satisfaction were assessed. The ease of obtaining arthroscopic views, the adequacy of these views, and the ease of performing partial meniscal resection or another procedure were similar in both groups according to scores assigned by the operating surgeon. Pain at 6 hours postoperatively was significantly less in the intra-articular anesthesia group but was similar in the 2 groups at 24 and 48 hours. Patients who were given intra-articular anesthesia reported higher satisfaction rates in understanding the underlying disease of the knee. We propose that intra-articular anesthesia alone can be effectively used in knee arthroscopies in which partial meniscal resection is anticipated. Level I, high-quality randomized controlled therapeutic trial.

Arthroscopic Lateral Meniscectomy in Knees With Lateral Compartment Osteoarthritis: A Case Series Study

The purpose of this study was to investigate the intermediate-term postoperative results of arthroscopic surgery for lateral compartment osteoarthritis (OA) of the knee in a case series study. In a series of 30 knees in 29 patients who underwent arthroscopic surgery for lateral compartment OA, we were able to observe 25 joints in 24 patients prospectively for the entire postoperative period. The follow-up period ranged from 1 to 13 years, with a mean of 5.5 +/- 3.7 years. The procedure in all cases comprised lateral partial meniscectomy with either abrasion arthroplasty, or debridement of the articular cartilage surface or microfracture. Of 25 cases, 13 underwent abrasion arthroplasty, 10 underwent debridement of the articular cartilage surface, and 2 underwent microfracture. Results were assessed by use of the postoperative knee score, findings of arthritic changes on plain knee radiographs, and other measurements of postoperative progress. Further surgery was required in 2 cases (8%) because of poor postoperative progress. In the remaining 22 patients, knee scores improved from a mean of 52.4 points preoperatively to 84.6 points postoperatively and mean function scores improved from 45.4 points to 82.6 points, with these favorable results being maintained at the last follow-up. The femoral-tibial angle decreased slightly as each year passed postoperatively. Radiologic progression of OA was seen at 3 years postoperatively in 7 patients (28%), but no progression was seen in 12 (48%). A positive correlation was seen between the preoperative femoral-tibial angle and postoperative results (R = 0.81, P < .01). When lateral compartment OA and lateral meniscal tears are both present, the clinical outcome of lateral meniscal resection was favorable. In patients with lateral compartment OA, therefore, an arthroscopic procedure, including meniscectomy, should be considered early. Level IV, therapeutic case series.

Contribution of runt‐related transcription factor 2 to the pathogenesis of osteoarthritis in mice after induction of knee joint instability

By producing instability in mouse knee joints, we attempted to determine the involvement of runt-related transcription factor 2 (RUNX-2), which is required for chondrocyte hypertrophy, in the development of osteoarthritis (OA). An experimental mouse OA model was created by surgical transection of the medial collateral ligament and resection of the medial meniscus of the knee joints of heterozygous RUNX-2-deficient (Runx2+/-) mice and wild-type littermates. Cartilage destruction and osteophyte formation in the medial tibial cartilage were compared by histologic and radiographic analyses. Localization of type X collagen and matrix metalloproteinase 13 (MMP-13) was examined by immunohistochemistry. Localization of RUNX-2 was determined by X-Gal staining in heterozygous RUNX-2-deficient mice with the lacZ gene insertion at the Runx2-deletion site (Runx2+/lacZ). Messenger RNA levels of type X collagen, MMP-13, and RUNX-2 were examined by real-time reverse transcriptase-polymerase chain reaction analysis. RUNX-2 was induced in the articular cartilage of wild-type mice at the early stage of OA, almost simultaneously with type X collagen but earlier than MMP-13. Runx2+/- and Runx2+/lacZ mice showed normal skeletal development and articular cartilage; however, after induction of knee joint instability, they exhibited decreased cartilage destruction and osteophyte formation, along with reduced type X collagen and MMP-13 expression, as compared with wild-type mice. RUNX-2 contributes to the pathogenesis of OA through chondrocyte hypertrophy and matrix breakdown after the induction of joint instability.

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.

New algorithm for selecting meniscal allografts that best match the size and shape of the damaged meniscus

Procedures used by tissue banks in selecting meniscal allografts that will best restore normal contact pressure at the time of surgical implantation into a recipient's knee should be improved. Our objective was to develop regression equations that use dimensions measured from magnetic resonance (MR) images of the contralateral knee to predict values of important meniscal parameters of the injured knee. Another objective was to incorporate these equations into an algorithm for selecting allografts that best match the size and shape of the damaged meniscus (either medial or lateral). In each of 10 knee specimens, four transverse and six cross-sectional parameters of the medial and lateral menisci were quantified from measurements obtained using a laser-based, noncontacting, 3-D coordinate digitizing system. In each of 10 contralateral knee specimens, six transverse and 24 cross-sectional (i.e., perpendicular to transverse plane) dimensions were measured for the medial and lateral menisci from MR images of each knee specimen. Simple linear regression equations related these 10 parameters to each of 38 predictor variables determined from magnetic resonance imaging (MRI) dimensions and the best regression equation for each parameter was identified. Requiring only 9 of the 30 dimensions as predictor variables, the best regression equations predicted 8 of 10 and 10 of 10 medial and lateral menisci parameters, respectively, with R2 values>0.500. The algorithm for selecting meniscal allografts involves: collecting an inventory of meniscal allografts and determining the 10 meniscus parameter values for all allografts in the inventory; measuring the dimensions as required from MRI scans of the uninjured knee; using the dimensions as inputs to the regression equations to predict values of meniscal parameters; and selecting the meniscal allograft from the inventory that best matches the predicted values of meniscal parameters. Selecting meniscal allografts using our new algorithm may enable allografts to better meet the clinical objectives of meniscal transplantation, which are to reduce pain in some patients following meniscal resection and to inhibit the degeneration of the articular cartilage.

Isolated medial meniscal tear in a Border Collie

A three-year-old, female Border Collie was successfully treated for an isolated, torn, medial meniscus by arthroscopic meniscal tear resection. The dog returned to agility competition without recurrence of lameness.

Repair of meniscal tears with the absorbable Clearfix screw: results after 1–3 years

Total meniscus resection usually leads to osteoarthritis of the knee joint. Preservation and refixation of the injured menisci are therefore of great clinical importance. The present study examines 40 meniscal injuries in 37 patients that were arthroscopically treated with Clearfix meniscal screws (Mitek, Norderstedt, Germany) in the period from August 1999 to December 2002. The mean patient age was 27.7 (range 16-62) years. Nine patients were female. A total of 24 patients (27 meniscal tears) also had an anterior cruciate ligament (ACL) lesion, and 5 patients had cartilage injuries. Twenty-two patients were treated within the first 2 weeks following the trauma, 10 patients within 8 weeks, and 5 patients after 8 weeks. The lesions were a bucket-handle tear of the medial meniscus in 11 cases and a bucket-handle tear of the lateral meniscus in 2 cases. The posterior horn of the medial meniscus was torn in 13 cases, and the pars intermedia in 3 cases. The posterior horn of the lateral meniscus was torn in 8 cases, and the pars intermedia in 3 cases. The mean tear length was 2.9 (+/- 1.5) cm and was fixed with an average of 1.8 (+/- 0.7) screws. In 7 cases, the anterior horn was treated with an additional meniscal suture. A total of 35 patients were examined after an average of 18 (range 7-45) months. In the event of a moderate outcome, MRI was performed as part of the follow-up investigation. The average Lysholm score was 93 (+/- 7.4), the Tegner activity index was 6.3 (+/- 2.0) before the accident and 5.8 (+/- 2.0) at the follow-up, the Marshall knee score was 47 (+/- 3.8). The VAS pain assessment was 1.6 (+/- 1.3) and the VAS function assessment was 7.9 (+/- 1.6). Of the 7 patients with a moderate result, 2 patients without additional ligament lesions suffered re-ruptures after and 13 months, respectively. The other 5 patients with a moderate result each had multiple accompanying injuries or pre-existing damage to the affected knee joint. The Clearfix screws achieved a clinical success rate of 82% in isolated meniscal tears in stable knee joints and a clinical success rate of 100% with additional ACL reconstruction. In view of the good clinical results and the simple procedure for use, the implant should be recommended for meniscal refixation.

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

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

Lésions traumatiques des ménisques du genou

Preserving the meniscal body after an injury to the meniscus is very important. Meniscal function is an integral part of the knee function and it is related to the integrity of ligaments and cartilage. The anatomy and physiology of the meniscus are reviewed, as well as the pathogenesis, symptomatology and current meniscal imaging. The authors focus on the treatment of meniscal lesions, addressing the conservative approach and the operative management, including proper meniscal resection and meniscal suture, and describe the current operative techniques. It would be interesting to know how meniscal lesions in a stable knee or associated with a ligamentous injury are treated. A discussion of potential complications related to the operative management of these lesions concludes this chapter.