Arthroscopic partial meniscectomy: 5-year follow-up

The Prevalence of Tibiofemoral Knee Osteoarthritis Following Arthroscopic Partial Meniscectomy Is Variably Reported in General, and Over Time: A Systematic Review With a Minimum of 5-Year Follow-Up

Purpose

Methods

Results

Conclusions

Level of Evidence

Better Outcomes but No Difference in Joint Space Narrowing at Five Years Among Patients Without Unstable Chondral Lesions Versus Those With Unstable Chondral Lesions (Left In Situ) at the Time of Arthroscopic Partial Meniscectomy

PURPOSE

To compare 5-year outcomes among patients with and without unstable chondral lesions undergoing arthroscopic partial meniscectomy (APM).

METHODS

Using data from the Chondral Lesions And Meniscal Procedures (ChAMP) Trial, we compared outcomes for patients with unstable chondral lesions found at the time of APM and left in situ (CL-noDeb, N = 71) versus patients without unstable chondral lesions (NoCL, N = 47) at 5 years after APM. Outcomes included the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analog pain scale, Short-form Health Survey (SF-36), physical knee measurements, progressive joint space narrowing on radiographs, and the rate of additional knee surgery. Multivariate linear regression was used to obtain mean differences (MDs) with corresponding 95% confidence intervals (CIs) adjusted for age, body mass index, and preoperative score (for postoperative scores).

RESULTS

Compared with CL-noDeb, NoCL subjects had significantly greater improvement at 5 years in the KOOS score for function in sport and recreation (MD = 9.9 [95% CI, 0.7-19.1]), SF-36 pain (MD = 13.9 [95% CI, 5.5-22.3]), knee extension (MD = 0.8 [95% CI, 0.1-1.5]), and decreased quadriceps circumference at the mid-portion of the patella (MD = -1.5 [95% CI, -2.7 to -0.3). A greater proportion of patients in the NoCL group achieved the MCID for all outcome scores except for the WOMAC pain score (89% CL-NoDeb vs 87% NoCL) and SF-36 general (29% CL-NoDeb vs 23% NoCL). There were no significant group differences in measures of progressive radiographic joint space narrowing in any compartments of the operative knee and no significant difference in the rate of additional knee surgery within 5 years of the initial APM.

CONCLUSIONS

Patients undergoing APM without unstable chondral lesions had statistically significantly better outcomes than patients with unstable chondral lesions at 5 years after surgery; however, there were no group differences in progressive radiographic joint space narrowing.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Post-Traumatic Osteoarthritis Assessment in Emerging and Advanced Pre-Clinical Meniscus Repair Strategies: A Review

Surgical repair of meniscus injury is intended to help alleviate pain, prevent further exacerbation of the injury, restore normal knee function, and inhibit the accelerated development of post-traumatic osteoarthritis (PTOA). Meniscus injuries that are treated poorly or left untreated are reported to significantly increase the risk of PTOA in patients. Current surgical approaches for the treatment of meniscus injuries do not eliminate the risk of accelerated PTOA development. Through recent efforts by scientists to develop innovative and more effective meniscus repair strategies, the use of biologics, allografts, and scaffolds have come into the forefront in pre-clinical investigations. However, gauging the extent to which these (and other) approaches inhibit the development of PTOA in the knee joint is often overlooked, yet an important consideration for determining the overall efficacy of potential treatments. In this review, we catalog recent advancements in pre-clinical therapies for meniscus injuries and discuss the assessment methodologies that are used for gauging the success of these treatments based on their effect on PTOA severity. Methodologies include histopathological evaluation of cartilage, radiographic evaluation of the knee, analysis of knee function, and quantification of OA predictive biomarkers. Lastly, we analyze the prevalence of these methodologies using a systemic PubMed® search for original scientific journal articles published in the last 3-years. We indexed 37 meniscus repair/replacement studies conducted in live animal models. Overall, our findings show that approximately 75% of these studies have performed at least one assessment for PTOA following meniscus injury repair. Out of this, 84% studies have reported an improvement in PTOA resulting from treatment.

Observation Versus Debridement of Unstable Chondral Lesions During Partial Meniscectomy: Analysis of Patient Outcomes and Degenerative Joint Disease at 5 Years in the Chondral Lesions And Meniscus Procedures (ChAMP) Randomized Controlled Trial

BACKGROUND

The purpose of this study was to examine the effect of debridement (CL-Deb) versus observation (CL-noDeb) of unstable chondral lesions on knee pain 5 years after arthroscopic partial meniscectomy (APM) in patients enrolled in the Chondral Lesions And Meniscus Procedures (ChAMP) Trial. Secondarily, other knee symptoms, function, general health, and the rate of additional surgery on the affected knee were examined.

METHODS

Patients aged ≥30 years who had an unstable Outerbridge grade-II, III, or IV chondral lesion when undergoing APM were randomly allocated to the CL-Deb (n = 98) or CL-noDeb (n = 92) group; ∼80% in each group completed a 5-year follow-up. Outcomes were measured preoperatively and at 5 years postoperatively, and included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) for pain, Short Form-36 (SF-36), physical knee measurements, knee radiographs, and rate of additional knee surgery at 5 years. The primary outcome was the 5-year WOMAC pain score. Group comparisons were made using the t test for continuous outcomes and the Fisher exact test for categorical outcomes.

RESULTS

There were no significant differences between the groups with respect to the primary outcome, the WOMAC pain score (CL-Deb: 86.0 [95% confidence interval (CI): 82.9 to 89.1]) versus CL-noDeb: 88.3 [95% CI: 85.5 to 91.1]; p = 0.27), or secondary outcomes at 5 years. There were also no differences in radiographic measurements of joint-space narrowing in any compartment (medial or lateral tibiofemoral or medial, central, or lateral patellofemoral) as well as no difference in the rate of additional knee surgery within 5 years after APM between the CL-Deb and CL-noDeb groups.

CONCLUSIONS

Outcomes for the CL-Deb and CL-noDeb groups did not differ at 5 years postoperatively, suggesting that there is no long-term benefit of arthroscopic debridement of chondral lesions encountered during APM.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

The results of meniscal allograft transplantation surgery: what is success?

BACKGROUND

Meniscal allograft transplantation (MAT) may improve symptoms and function, and may limit premature knee degeneration in patients with symptomatic meniscal loss. The aim of this retrospective study was to examine patient outcomes after MAT and to explore the different potential definitions of 'success' and 'failure'.

METHODS

Sixty patients who underwent MAT between 2008 and 2014, aged 18-50 were identified. Six validated outcome measures for knee pathologies, patient satisfaction and return to sport were incorporated into a questionnaire. Surgical failure (removal of most/all the graft, revision MAT or conversion to arthroplasty), clinical failure (Lysholm < 65), complication rates (surgical failure plus repeat arthroscopy for secondary allograft tears) and whether patients would have the procedure again were recorded. Statistics analysis included descriptive statistics, with patient-reported outcome measures reported as median and range. A binomial logistic regression was performed to assess factors contributing to failure.

RESULTS

Forty-three patients (72%) responded, mean age 35.6 (±7.5). 72% required concomitant procedures, and 44% had Outerbridge III or IV chondral damage. The complication rate was 21% (9). At mean follow-up of 3.4 (±1.6) years, 9% (4) were surgical failures and 21% (9) were clinical failures. Half of those patients considered a failure stated they would undergo MAT again. In the 74% (32) reporting they would undergo MAT again, median KOOS, IKDC and Lysholm scores were 82.1, 62.1 and 88, compared to 62.2, 48.5 and 64 in patients who said they would not. None of the risk factors significantly contributed to surgical or clinical failure, although female gender and number of concomitant procedures were nearly significant. Following MAT, 40% were dissatisfied with type/level of sport achieved, but only 14% would not consider MAT again.

CONCLUSIONS

None of the risk factors examined were linked to surgical or clinical failure. Whilst less favourable outcomes are seen with Outerbridge Grade IV, these patients should not be excluded from potential MAT. Inability to return to sport is not associated with failure since 73% of these patients would undergo MAT again. The disparity between 'clinical failure' and 'surgical failure' outcomes means these terms may need re-defining using a specific/bespoke MAT scoring system.

Surgical interventions for symptomatic mild to moderate knee osteoarthritis

BACKGROUND

Osteoarthritis affecting the knee is common and represents a continuum of disease from early cartilage thinning to full-thickness cartilage loss, bony erosion, and deformity. Many studies do not stratify their results based on the severity of the disease at baseline or recruitment.

OBJECTIVES

To assess the benefits and harms of surgical intervention for the management of symptomatic mild to moderate knee osteoarthritis defined as knee pain and radiographic evidence of non-end stage osteoarthritis (Kellgren-Lawrence grade 1, 2, 3 or equivalent on MRI/arthroscopy). Outcomes of interest included pain, function, radiographic progression, quality of life, short-term serious adverse events, re-operation rates and withdrawals due to adverse events.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase up to May 2018. We also conducted searches of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for ongoing trials. Authors of trials were contacted if some but not all their participants appeared to fit our inclusion criteria.

SELECTION CRITERIA

We included randomised controlled trials that compared surgery to non-surgical interventions (including sham and placebo control groups, exercise or physiotherapy, and analgesic or other medication), injectable therapies, and trials that compared one type of surgical intervention to another surgical intervention in people with symptomatic mild to moderate knee osteoarthritis.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data using standardised forms. We analysed the quality of evidence using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.

MAIN RESULTS

A total of five studies involving 566 participants were identified as eligible for this review. Single studies compared arthroscopic partial meniscectomy to physical therapy (320 participants), arthroscopic surgery (debridement ± synovectomy ± chondroplasty) to closed needle joint lavage with saline (32 participants) and high tibial osteotomy surgery to knee joint distraction surgery (62 participants). Two studies (152 participants) compared arthroscopic surgery (washout ± debridement; debridement) to a hyaluronic acid injection. Only one study was at low risk of selection bias, and due to the difficulty of blinding participants to their treatment, all studies were at risk of performance and detection bias.Reporting of results in this summary has been restricted to the primary comparison: surgical intervention versus non-surgical intervention.A single study, included 320 participants with symptoms consistent with meniscal tear. All subjects had the meniscal tear confirmed on knee MRI and radiographic evidence of mild to moderate osteoarthritis (osteophytes, cartilage defect or joint space narrowing). Patients with severe osteoarthritis (KL grade 4) were excluded. The study compared arthroscopic partial meniscectomy and physical therapy to physical therapy alone (a six-week individualised progressive home exercise program). This study was at low risk of selection bias and outcome reporting biases, but was susceptible to performance and detection biases. A high rate of cross-over (30.2%) occurred from the physical therapy group to the arthroscopic group.Low-quality evidence suggests there may be little difference in pain and function at 12 months follow-up in people who have arthroscopic partial meniscectomy and those who have physical therapy. Evidence was downgraded to low quality due to risk of bias and imprecision.Mean pain was 19.3 points on a 0 to 100 point KOOS pain scale with physical therapy at 12 months follow-up and was 0.2 points better with surgery (95% confidence interval (CI) 4.05 better to 3.65 points worse with surgery, an absolute improvement of 0.2% (95% CI 4% better to 4% worse) and relative improvement 0.4% (95% CI 9% better to 8% worse) (low quality evidence). Mean function was 14.5 on a 0 to 100 point KOOS function scale with physical therapy at 12 months follow-up and 0.8 points better with surgery (95% CI 4.3 better to 2.7 worse); 0.8% absolute improvement (95% CI 4% better to 3% worse) and 2.1% relative improvement (95% CI 11% better to 7% worse) (low quality evidence).Radiographic structural osteoarthritis progression and quality of life outcomes were not reported.Due to very low quality evidence, we are uncertain if surgery is associated with an increased risk of serious adverse events, incidence of total knee replacement or withdrawal rates. Evidence was downgraded twice due to very low event rates, and once for risk of bias.At 12 months, the surgery group had a total of three serious adverse events including fatal pulmonary embolism, myocardial infarction and hypoxaemia. The physical therapy alone group had two serious adverse events including sudden death and stroke (Peto OR 1.58, 95% CI 0.27 to 9.21); 1% more events with surgery (95% CI 2% less to 3% more) and 58% relative change (95% CI 73% less to 821% more). One participant in each group withdrew due to adverse events.Two of 164 participants (1.2%) in the physical therapy group and three of 156 in the surgery group underwent conversion to total knee replacement within 12 months (Peto OR 1.76, 95% CI 0.43 to 7.13); 1% more events with surgery (95% CI 2% less to 5% more); 76% relative change (95% CI 57% less to 613% more).

AUTHORS' CONCLUSIONS

The review found no placebo-or sham-controlled trials of surgery in participants with symptomatic mild to moderate knee osteoarthritis. There was low quality evidence that there may be no evidence of a difference between arthroscopic partial meniscectomy surgery and a home exercise program for the treatment of this condition. Similarly, low-quality evidence from a few small trials indicates there may not be any benefit of arthroscopic surgery over other non-surgical treatments including saline irrigation and hyaluronic acid injection, or one type of surgery over another. We are uncertain of the risk of adverse events or of progressing to total knee replacement due to very small event rates. Thus, there is uncertainty around the current evidence to support or oppose the use of surgery in mild to moderate knee osteoarthritis. As no benefit has been demonstrated from the low quality trials included in this review, it is possible that future higher quality trials for these surgical interventions may not contradict these results.

Changes Within Clinical Practice After a Randomized Controlled Trial of Knee Arthroscopy for Osteoarthritis

BACKGROUND

In 2002, Moseley et al published a randomized controlled trial (RCT) that showed no difference between knee arthroscopy and placebo for patients with osteoarthritis (OA). We wanted to assess the impact of the trial on clinical practice in the United States.

PURPOSE/HYPOTHESIS

To evaluate changes in knee arthroscopy practice before and after publication of the article by Moseley et al and to assess the effect of this landmark RCT on the behavior of practicing orthopaedic surgeons. We hypothesized that after publication of the Moseley trial, the overall frequency of knee arthroscopy would decrease, that the mean age of patients undergoing knee arthroscopy would decrease, and that the proportion of arthroscopies for a diagnosis of OA would decrease.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The State Ambulatory Surgery Database was used to analyze cases from 1998 to 2006, which were classified as meniscus tear, OA, or OA with meniscus tear. Changes in age, surgery rates, and case classification were evaluated before and after Moseley's trial using Student t tests and analysis of variance.

RESULTS

After publication of the trial, the number of knee arthroscopies per year increased from 155,057 in 1998 to 172,317 in 2006 (P ≤ .001). Mean patient age increased from 47.6 to 49.2 years (P < .001). Meniscus tears increased from 69.1% to 70.8%, representing approximately 15,500 additional cases per year. OA decreased from 10.6% to 7.2%, representing approximately 4000 fewer cases per year. OA with meniscus tear increased from 20.3% to 22.0%, representing approximately 6400 additional cases per year.

CONCLUSION

While overall age and rates of knee arthroscopy increased contrary to our hypothesis, we identified a decrease in rates of knee arthroscopy for OA after publication of the Moseley trial, demonstrating that well-publicized RCTs can influence patterns of clinical practice.

Changes in articular cartilage following arthroscopic partial medial meniscectomy

PURPOSE

To examine degenerative changes in all cartilage surfaces of the knee following arthroscopic partial medial meniscectomy.

METHODS

For this prospective cohort study, 14 patients (five female) with a mean age of 47.9 ± 12.9 years who had undergone isolated arthroscopic partial medial meniscectomy were evaluated. Cartilage-sensitive magnetic resonance imaging (MRI) scans were acquired from the operated knees before the index operations, as well as at 6, 12, and 24 months after surgery. The MRI scans were assessed for the prevalence, severity, and size of cartilage degenerations. The clinical outcome was assessed using the SF-36 physical and mental component score and the International Knee Documentation Committee Knee Evaluation Form and was correlated with radiological findings.

RESULTS

There was a significant increase in the severity of cartilage lesions in the medial tibial plateau (P = 0.019), as well as a trend towards an increase in the lateral tibial plateau. The size of the cartilage lesions increased significantly in the medial femoral condyle (P = 0.005) and lateral femoral condyle (P = 0.029), as well as in the patella (P = 0.019). Functional outcome scores improved significantly throughout the follow-up period. There was no correlation between cartilage wear and functional outcome.

CONCLUSIONS

Arthroscopic partial medial meniscectomy is associated with adverse effects on articular cartilage and may lead to an increase in the severity and size of cartilage lesions. Post-operative cartilage wear predominantly affected the medial compartment and also affected the other compartments of the knee. Strategies to reduce subsequent osteoarthritic changes need to involve all compartments of the knee.

LEVEL OF EVIDENCE

IV.

Meniscectomy

To review the meniscus from a historical perspective especially on surgical management and general guidelines for arthroscopic meniscectomy procedures for various types of meniscal tears. We searched MEDLINE and PubMed for the years of 1980-2010 using the terms meniscus, meniscal repair, menisectomy, and arthroscopy. Orthopedic surgeons frequently encounter patients with pain or functional impairment of the knee joint and repair or resection of the injured meniscus is one of the most common orthopedic operative procedures. The object of meniscal surgery is to reduce pain, restore functional meniscus and prevent the development of degenerative osteoarthritis in the involved knee. Historically, total meniscectomy was a common procedure performed for meniscus tear symptoms. However, it has been reported that total meniscectomy has deleterious effects on the knee. In the past, the menisci were thought as a functionless remnant tissue. Currently, it is known that the meniscus is an important structure for knee joint function. Menisci provide several vital functions including mechanical support, localized pressure distribution, and lubrication to the knee joint. It is widely accepted that the function of the meniscus can be preserved through minimal excision. An arthroscopic partial meniscectomy preserving more of the meniscus is preferred over total meniscectomy. In recent decades, this shift toward arthroscopic partial meniscectomy has led to the development of new surgical techniques.

Meniscectomy as a risk factor for knee osteoarthritis: a systematic review

INTRODUCTION

This review defines the recognized risk factors responsible for the development of knee osteoarthritis after surgical management of meniscal tears.

SOURCES OF DATA

We performed a literature search using Medline, Ovid, Cochrane and Google Scholar using the keywords: 'Meniscal tears', 'meniscectomy', 'osteoarthritis', 'complications' and 'risk factors'. Thirty-two published studies were identified.

AREAS OF AGREEMENT

In the long term, osteoarthritis develops in the knee of patients undergoing surgery for meniscal tears. The Coleman methodology score showed great heterogeneity in terms of patient characteristics and outcome assessment. Amount of meniscus removed, duration of pre-operative symptoms and lateral meniscectomy show strong statistical association to onset of knee osteoarthritis.

AREAS OF CONTROVERSY

We did not find univocal findings defining the risk factors responsible for the development of post-operative knee osteoarthritis.

GROWING POINTS

There is a need for standardized clinical and imaging validated scale to improve definition of post-operative knee osteoarthritis to allow easier and more reliable comparison of outcomes in different studies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Appropriately powered randomized controlled trials reporting clinical and imaging-related outcomes in patients undergoing arthroscopic minimally invasive procedures and meniscal suturing should be performed. Comparing imaging findings of patients undergoing arthroscopic partial and open meniscectomy, a lower incidence of knee osteoarthritic evolution was detected after arthroscopy. The amount of removed meniscus is the most important predictor factor for the development of osteoarthritis. Minimally invasive procedures seem to reduce the incidence of long-term osteoarthritic changes of the knee compared with more invasive open and or arthroscopic procedures.

Quantitative magnetic resonance imaging detects changes in meniscal volume in vivo after partial meniscectomy

BACKGROUND

Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment. Purpose/

HYPOTHESIS

To determine whether quantitative magnetic resonance imaging (qMRI) can detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI would be reliable for determining meniscal volume within the repeated images of unresected menisci. Additionally, we expected no significant difference in volume between the uninjured menisci of the injured knees and the same menisci of the uninjured knees.

STUDY DESIGN

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

METHODS

Ten subjects with meniscal tears were evaluated with 3-T MRI before and after arthroscopic PM. Manual segmentation was used to create models of the menisci and to determine the preoperative and postoperative meniscal volumes for each subject. The responsiveness and reliability of qMRI for determining meniscal volume in vivo were evaluated using these measurements. We expected a decrease in volume of the resected menisci, but not in the uninjured menisci, after surgery.

RESULTS

The mean preoperative volume of the injured menisci was significantly greater than the mean postoperative volume (2896 +/- 277 vs 2480 +/- 277 mm(3); P = .000). There was no significant difference between the mean preoperative and postoperative volumes of the uninjured menisci (2687 +/- 256 vs 2694 +/- 256 mm(3); P = 1.000).

CONCLUSION

Manual segmentation demonstrated a significant reduction in the volume of the surgically resected menisci after PM, but no significant change in the volume of unresected meniscal tissue, indicating that the manual segmentation method is responsive.

CLINICAL RELEVANCE

This approach offers a novel, reliable method to study the relationship between the volume of meniscal tissue removed during PM and subsequent patient outcomes during long-term clinical studies.

Medical decision making in patients with knee pain, meniscal tear, and osteoarthritis

OBJECTIVE

Meniscal tears and osteoarthritis (OA) frequently coexist, but to our knowledge, no data exist to identify who will benefit from arthroscopic partial meniscectomy (APM) versus nonoperative management. Our objective was to evaluate the capability of preoperative information to predict APM outcomes in OA.

METHODS

Using a mathematical model and published data, we combined 2 clinical (mechanical symptoms and pain pattern) and 2 magnetic resonance imaging (tear type and bone marrow lesions) indicators into 36 possible combinations and ranked each combination according to the likelihood of having primarily tear- versus OA-related pain in individuals ages 45-65 years with knee pain, OA, and meniscal tears. By considering alternative thresholds for performing APM, we identified the cutoff rank that maximized the overall population International Knee Documentation Committee (IKDC) score (0-100 scale).

RESULTS

Rank 1 (e.g., displaced tear, locking, increased pain, no bone marrow lesions) represented the highest likelihood of APM benefit; rank 36 (e.g., oblique tear, no mechanical symptoms, static pain, severe bone marrow lesions) represented the lowest likelihood of APM benefit. Indeterminate middle ranks included individuals with mixed findings (i.e., 2 findings consistent with high and 2 with low likelihood of APM benefit). APM thresholds between ranks 17 and 23 resulted in >82% of the population receiving treatment producing the greatest possible IKDC improvement, with mean incremental gains in IKDC score of >24 points. Findings were robust across a broad range of indicator assumptions, but were sensitive to outcome assumptions.

CONCLUSION

Among individuals with degenerative meniscal tears and OA, easily obtainable clinical information can differentiate those who are more likely to benefit from APM.

Arthroscopic collagen meniscus implant results at 6 to 8 years follow up

Meniscal substitution is a fundamental procedure to prevent osteoarthritis of the knee after massive meniscectomy. Stone, Steadman and Rodkey have developed a bioreadsorbable collagen matrix (CMI) which acts as a scaffold to restore the original medial meniscal. The objective of this study was to prospectively evaluate the results of CMI implantation at a follow up from a minimum of 6 to a maximum of 8 years. Eight patients (mean age 25) were evaluated at a final observation point from 6 to 8 years after CMI implantation. Inclusion criteria were an irreparable meniscal tear or a previous meniscectomy involving the medial meniscus. Follow up evaluation included Cincinnati Knee Rating Scale (CKRS), IKDC, subjective evaluation and X-ray and MRI control. There were no complications related to the device. All patients were able to return to day activities without limitations 3 months after surgery. Both subjective CKRS score and objective IKDC score showed improvement in all cases except one patient with an ACL re-injury. In two cases scores were slightly worse from 2 years after surgery to the final observation point. The other five cases obtained maximum score at final follow-up. In four cases the absence of pain remained until the final observation point, while in four cases a low entity of pain was described at long term follow-up. MRI showed in five cases mixoid degeneration signal, two had normal signal with reduced size, while one patient had no recognizable implant. Six patients had preserved cartilage and articular space, with no changes respect to pre-op control. Arthroscopic second look evaluation has been performed in three cases, revealing in two cases the presence of the implant, although with a reduced size respect to the original one, while in one case the CMI was almost disappeared. Our small series of eight patients prospectively followed from 6 to 8 years of follow-up has shown highly satisfactory results. Although the aspect of the implant was mostly abnormal, the implant may have helped reduce the deterioration of the knee joint at final observation time.

MRI evaluation of isolated arthroscopic partial meniscectomy patients at a minimum five-year follow-up

BACKGROUND

The risk of radiographic knee degeneration after partial or total meniscectomy is well documented, but no prior study has employed cartilage-sensitive MRI technology to assess degenerative changes after meniscectomy.

HYPOTHESIS

Arthroscopic partial meniscectomy results in early articular cartilage wear and subchondral bony degeneration, even in the absence of clinical symptoms, and these findings can be evaluated with cartilage-sensitive MRI.

STUDY DESIGN

Retrospective cohort.

METHODS

Twenty-nine patients (ages: 15-40) who had undergone isolated arthroscopic partial medial or lateral meniscectomy with at least 5-year follow-up were evaluated. All patients had arthroscopically normal articular cartilage at the time of initial meniscectomy. Seventeen patients (18 knees) underwent partial medial meniscectomy (MM) and 12 patients underwent partial lateral meniscectomy (LM) with mean follow-up of 8.4 and 7.1 years, respectively. Follow-up evaluation included physical examination, outcome questionnaires, and cartilage-sensitive MRI examination with modified Outerbridge grading of articular surfaces.

RESULTS

Outerbridge grades II-IV were noted in 64% of medial compartment joint surfaces in group MM knees versus 33% of lateral compartment joint surfaces in group LM knees. Abnormal cartilage surfaces (grades II-IV), subchondral sclerosis, and condylar squaring were all significantly more frequent after medial meniscectomy (p < 0.05). Groups MM and LM had no significant differences among outcome scores, which remained excellent in both groups. A significant negative correlation was found between the severity of cartilage wear and functional scoring in the MM group, suggesting that functional disability lags behind early MRI evidence of degeneration.

CONCLUSIONS

Despite optimal preoperative prognostic factors and excellent functional outcomes, MRI evidence of early articular cartilage degeneration was present in both partial medial and lateral meniscectomy patients at a minimum 5-year follow-up. Results support the use of cartilage-sensitive MRI as a noninvasive screening technique to evaluate cartilage changes after arthroscopic partial meniscectomy and may help to counsel the high-risk patient in regard to postoperative activity.

Meniscal replacement in dogs. Tissue regeneration in two different materials with similar properties

In earlier studies, meniscal replacement with a porous polymer implant led to regeneration of neo-meniscal tissue. To evaluate the influence of the chemical properties on the tissue regeneration in the implant, in the present study, the meniscus in the dog's knee was replaced with either an aromatic 4,4-diphenylmethanediisocyanate based polyesterurethane implant (Estane) (n = 6) or with an aliphatic 1,4-butanediisocyanate based polyesterurethane implant (PCLPU) (n = 6). After 6 months, the knee joints were resected and the tissue behavior in the two different prostheses was evaluated microscopically. In both prostheses, a meniscus-like distribution of the tissue phenotype was found with collagen type I in the peripheral fibrous zones and collagen type II in the central, more cartilaginous zones. The compression-stress behavior of the implant-tissue construct remained in between the stiffness of the polymer material and that of the native meniscus. The PCLPU implant seemed to provoke less synovial tissue reaction. After meniscectomy solely, in 5 out of 6 cases, a meniscus-like regenerate was formed. Furthermore, the articular cartilage degeneration after placing a PCLPU implant did also not exceed the degeneration after the Estane implant or after meniscectomy. The differences between these two implants did not seem to influence the tissue regeneration in the implant. However, PCLPU seemed to evoke less tissue reaction and, therefore, is thought to be less or even nontoxic as compared with the Estane implant. Therefore, for studies in the future, the authors prefer the PCLPU prostheses for replacement of the meniscus.

Associations among preoperative MRI features and functional status following arthroscopic partial meniscectomy

BACKGROUND

Arthroscopic partial meniscectomy (APM) is the most frequently performed orthopedic procedure. Functional outcomes of APM are variable, particularly among patients with underlying knee osteoarthritis. While most patients undergoing APM have knee magnetic resonance imaging (MRI) performed preoperatively, the prognostic value of knee MRI in predicting the functional outcomes of APM has not been evaluated.

METHODS

We studied patients who had APM performed by one of five participating surgeons at one institution in 2002. The preoperative MRI scans of these patients were assessed using a standardized rating system by an independent observer who was not involved in the care of the patients and who was blinded to patient outcomes. Patients completed a questionnaire in the summer of 2003, 6-18 months postoperatively. The questionnaire included the Knee Injury and Osteoarthritis Outcome Score (KOOS) and items on satisfaction with the results of surgery. We used bivariate and multivariate techniques to evaluate the associations between MRI findings, other preoperative findings, and the functional status and pain scales of the KOOS.

RESULTS

Eighty-three patients were included in the analyses. The outcome of surgery was variable with average KOOS functional score of 77 and range of 15-100. One-quarter of patients were somewhat or very dissatisfied with the results of surgery and 17% were using a cane at the time of follow-up. In bivariate analyses, preoperative predictors of KOOS function score at follow-up included preoperative functional status and several MRI findings including the extent of cartilage damage, bone marrow edema in the medial compartment, and length of the tear. Multivariate analyses showed that after adjusting for preoperative functional status, the extent of cartilage signal abnormality in the medial compartment on MRI remained an independent predictor of functional status, 6-18 months following surgery. Specifically, preoperative functional status explained 21% of the variability in follow-up KOOS functional status score and the extent of medial tibial cartilage damage on MRI explained an additional 16%. Analyses of knee pain 1 year following APM yielded similar findings, with preoperative functional status accounting for 17% of the variability in pain scores and medial tibial cartilage damage accounting for an additional 13%.

CONCLUSIONS

Preoperative MRI findings of cartilage damage have independent prognostic value in predicting the functional outcome of APM. This study was limited by a cross-sectional design with retrospective recall of preoperative functional status. Thus, the findings need to be confirmed in prospective investigations.

Minimally invasive unicondylar knee arthroplasty for the treatment of unicompartmental osteoarthritis: an outpatient arthritic bypass procedure

This review summarizes past studies examining the progression of osteoarthritis (OA) of the knee that have led to the conclusion that the disease is slow, progressive, and typically limited to one tibiofemoral compartment. Treatments such as unicondylar knee arthroplasty (UKA) that address the single diseased compartment, preserving bone and soft tissue, seem appropriate. The senior author's minimally invasive surgical technique for performing UKA also is described.

The long-term evaluation of lateral meniscus tears left in situ at the time of anterior cruciate ligament reconstruction

PURPOSE

The goal of this study was to determine the long-term subjective and objective results for patients with lateral meniscus tears found at the time of anterior cruciate ligament (ACL) reconstruction that were left in situ or abraded and trephined but not repaired or removed.

TYPE OF STUDY

Retrospective review of prospectively collected data.

METHODS

From a database of ACL reconstruction patients, 332 patients were noted to have lateral meniscus tears that were left in situ or underwent abrasion and trephination. Exclusion criteria included lateral or medial partial meniscectomy, previous knee surgery, or greater than grade II chondromalacia in any knee compartment. The tears were classified as posterior horn tears (n = 70), stable radial flap tears (n = 50), or peripheral or posterior tears (n = 212). Patients were evaluated subjectively using a modified Noyes knee questionnaire and objectively using International Knee Documentation Committee (IKDC) criteria.

RESULTS

At a mean of 6.6 years (range, 2 to 16.5 years) after surgery, the mean total modified Noyes score for 239 patients was 93.8 +/- 7.6 points. At a mean of 5.1 +/- 3.8 years after surgery, the objective IKDC evaluation showed that 163 of 170 (96%) patients had an overall rating of normal or nearly normal. Radiographic evaluation showed that 162 patients (95%) had a normal rating, 6 patients had a nearly normal rating and 2 patients had an abnormal rating. Of 332 patients, only 8 (2.4%) required subsequent surgery for the lateral meniscus.

CONCLUSIONS

Lateral meniscus tears that are posterior horn tears, stable radial flap tears, or peripheral or posterior third tears that do not extend further than 1 cm in front of the popliteus tendon can be treated successfully with abrasion and trephination or by being left in situ.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

A comparative study of medial versus lateral arthroscopic partial meniscectomy on stable knees: 10-year minimum follow-up

PURPOSE

Our goal was to compare results of partial medial arthroscopic meniscectomy with results of partial lateral arthroscopic meniscectomy and to determine prognostic factors.

TYPE OF STUDY

Retrospective comparative study with statistical analysis.

METHODS

In this study, 362 medial and 109 lateral isolated arthroscopic meniscectomies are presented with a minimum follow-up time of 10 years. All knees were stable with no previous surgery or traumatic lesion.

RESULTS

In this study, 95% of the patients were very satisfied or satisfied with the results of the medial meniscectomy, and 95.5% with results of the lateral meniscectomy (P =.32). According to grades 1 and 2 of the International Knee Documentation Committee (IKDC) form, 85.8% of the medial meniscectomy group were free of any symptoms, as were 79.7% of the lateral meniscectomy group (P =.11). Radiologic changes after medial and lateral meniscectomy were found in 21.5% and 37.5%, respectively (P =.11). The rates of radiologic changes in patients in whom the contralateral knee was radiologically normal were 22.3% and 39%, respectively (P =.016). The rate of repeat surgeries for osteoarthritis was less than 0.2%.

CONCLUSIONS

Subjective and clinical results after medial or lateral meniscectomy are quite similar, but radiologic results are significantly worse after lateral meniscectomy. The most accurate way to determine the degeneration caused by the meniscectomy is to evaluate joint space narrowing in patients in whom the contralateral knee was radiologically normal. Otherwise, partial medial or lateral meniscectomy are well tolerated. A better prognosis can be predicted for a patient with an isolated medial meniscal tear with one or more of the following factors: age less than 35 years, a vertical tear, no cartilage damage, and an intact meniscal rim at the end of the meniscectomy. With an isolated lateral meniscal tear, a better prognosis can be predicted if the patient is young and has an intact meniscal rim at the end of the meniscectomy.