Meniscal Extrusions: Imaging and Repair
This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.
Loss of hoop stress by either medial or lateral menisci can cause meniscal extrusion, which results in increased forces on articular cartilage. The degree of meniscal extrusion is typically measured as a 2-dimensional distance with MRI. However, investigators recently used 3-D MRI to analyze the relationship between medial meniscal extrusion (MME) and femoral cartilage change in patients with these tears.1
Fifteen males (mean age of 56 years) with a medial meniscal degenerative tear (grade 3 by the Mink classification) based on MRI were included. The cartilage area was reconstructed in 3-D, and the femoral cartilage was projected in 2-D by 3-D MRI analysis. The femoral cartilage of the femorotibial joint was divided into 4 segments, and the cartilage area ratio was defined as the ratio of cartilage with thickness ≥1.0 mm in each segment. The tibial MME area (mm2) and volume (cm3), excluding osteophytes, were measured by 3-D MRI.
The projected cartilage area ratio (cartilage thickness ≥1.0 mm) at the posteromedial segment was lower than the ratio at the other 3 segments. The cartilage area ratio at the posteromedial segment was not correlated with the MME distance measured by the 2-D MRI, but it was negatively correlated with MME area (r=-0.53, p=0.045) and MME volume (r=-0.62, p=0.016) as measured by 3-D MRI. Overall, the 3-D imaging more accurately reflected cartilage damage.
Both radial tears and posterior horn degeneration can lead to meniscal extrusion. When this injury is seen acutely in younger persons, repairs are often attempted. Recently efforts have been made to do repairs in older individuals. The use of cell-seeded nanofibrous scaffolds to repair radial tears and resulting hoop-structure injuries has been studied for prevention of articular cartilage degeneration using a rabbit model.2
Synovial mesenchymal stem cells were isolated and expanded into sheets that were then wrapped onto poly(e-caprolactone) scaffolds to create stable cell/scaffold tissue-engineered constructs (TECs). Scaffold-alone or TEC + scaffold constructs were then sutured into created radial meniscal defects (12 rabbits in each group).
The TEC-scaffold group maintained the structure of the hyaline cartilage with matrix staining with Safranin O up to 12 weeks after surgery. Although the cartilage coverage decreased in both groups, the TEC-scaffold group did not become significantly worse over time, suggesting stabilization of hoop structure integrity. Only the TEC-scaffold group showed repair tissue that exhibited positive Safranin O staining in the inner zone of the meniscus.
Future studies will be required to determine the role of tissue engineering in the preservation of meniscal coverage in the face of radial tears.
References
- Suzuki S, Ozeki N, Kohno Y, Mizuno M, Otabe K, Katano H, Tsuji K, Suzuki K, Itai Y, Masumoto J, Koga H, Sekiya I. Medial meniscus extrusion (MME) area and MME volume determined by 3D-MRI are more sensitive than MME distance determined by 2D-MRI for evaluating cartilage loss in knees with medial meniscus degenerative tears. ORS 2019 Annual Meeting Poster No. 0514.
- Shimomura K, Rothrauff BB, Hart DA, Hamamoto S, Kobayashi M, Yoshikawa H, Tuan RS, Nakamura N. Enhanced Repair of Meniscal Hoop Structure Injuries Using An Aligned Electrospun Nanofibrous Scaffold Combined with a Mesenchymal Stem Cell-derived Tissue Engineered Construct. ORS 2019 Annual Meeting Poster No. 0519.
What’s New in Adult Reconstructive Knee Surgery 2018, Part II
Previously this month, Chad A. Krueger, MD, JBJS Deputy Editor for Social Media, selected what he deemed to be the most clinically compelling findings from among the more than 150 studies cited in the January 17, 2018 Specialty Update on Adult Reconstructive Knee Surgery. In this OrthoBuzz post, Gwo-Chin Lee, MD, author of the Specialty Update on Adult Reconstructive Knee Surgery, selects his “top five.”
Nonoperative Knee OA Treatment
—Atukorala et al. found a significant dose-response relationship between all KOOS subscales and percentage of weight change across all weight-change categories. Participants required ≥7.7% of weight loss to achieve a minimal clinically important improvement in function.1
Meniscal Injuries
—A prospective cohort study showed that patients undergoing arthroscopic procedures for degenerative meniscal tears did not have clinically meaningful differences in outcomes compared with patients with traumatic meniscal tears.2
Postoperative Pain Management
—Authors of a Cochrane Systematic Review ascertained that liposomal bupivacaine at the surgical site appears to reduce postoperative pain compared with placebo. However, because of the low quality and volume of evidence, it is not possible to determine its effect compared with conventional agents.3
Avoiding Post-TKA Complications
—In a randomized trial, the use of a tourniquet resulted in upregulation of peptidase activity within the vastus medialis but did not result in an increase in muscular degradation products. The authors concluded that the relationship between tourniquet-induced ischemia and muscle atrophy is complex and poorly understood.4
—The authors of a registry study found no evidence that fondaparinux, enoxaparin, or warfarin are superior to aspirin in the prevention of PE, DVT, or VTE—or that aspirin is safer than these alternatives. However, enoxaparin is as safe as aspirin with respect to bleeding, and fondaparinux is as safe as aspirin with respect to risk of wound complications.5
References
- Atukorala I, Makovey J, Lawler L, Messier SP, Bennell K, Hunter DJ. Is there a dose-response relationship between weight loss and symptom improvement in persons with knee osteoarthritis? Arthritis Care Res (Hoboken). 2016 Aug;68 (8):1106-14.
- Thorlund JB, Englund M, Christensen R, Nissen N, Pihl K, Jørgensen U, Schjerning J, Lohmander LS. Patient reported outcomes in patients undergoing arthroscopic partial meniscectomy for traumatic or degenerative meniscal tears: comparative prospective cohort study. BMJ. 2017 Feb 2;356:j356.
- Hamilton TW, Athanassoglou V, Mellon S, Strickland LH, Trivella M, Murray D, Pandit HG. Liposomal bupivacaine infiltration at the surgical site for the management of postoperative pain. Cochrane Database Syst Rev. 2017 Feb 1;2:CD011419.
- Jawhar A, Hermanns S, Ponelies N, Obertacke U, Roehl H. Tourniquet-induced ischaemia during total knee arthroplasty results in higher proteolytic activities within vastus medialis cells: a randomized clinical trial. Knee Surg Sports Traumatol Arthrosc. 2016 Oct;24(10):3313-21. Epub 2015 Nov 14.
- Cafri G, Paxton EW, Chen Y, Cheetham CT, Gould MK, Sluggett J, Bini SA, Khatod M. Comparative effectiveness and safety of drug prophylaxis for prevention of venous thromboembolism after total knee arthroplasty. J Arthroplasty. 2017 Nov;32(11):3524-28.e1. Epub 2017 May 31.
Can Only 4 Questions Yield Meaningful Patient Outcome Measures?
In today’s data-driven, evidence-based world of orthopaedics, capturing accurate information about a patient’s physical function can require patients to answer dozens of separate questions. In the June 7, 2017 edition of JBJS, Hancock et al. investigate whether the computer-based tool called PROMIS (Patient-Reported Outcomes Measurement Information System) PF CAT is more efficient than and just as reliable as the more burdensome function-evaluation instruments.
In short, the answer is yes. Among a group of otherwise healthy patients scheduled to undergo meniscal surgery, the PROMIS PF CAT scores were generally highly correlated with traditional patient-reported physical-function measures, such as the SF-36 Physical Function instrument and the KOOS Sport and Quality-of-Life scores.
In contrast to the more traditional fixed-length questionnaires, the PROMIS PF CAT presents an initial item to the patient, and uses the response to that to select the most informative next item. That process continues only until a predefined level of precision is reached, at which point the test ends. The vast majority (89%) of the patients in this study completed the PROMIS PF CAT after answering only four items.
Considering its strong correlation with other widely accepted measurement tools and its efficiency, the authors conclude that PROMIS PF CAT “may be a good alternative for evaluating physical function in meniscal injury populations,” and that it could help “reduce burnout and maintain high response rates” in a time-constrained health care environment.
A Close Look at Crossovers in Knee RCTs
In a November 16, 2016 JBJS study whose findings have implications for both research and practice, Katz et al. analyzed data from the MeTeOR trial to answer two questions:
- What prompts patients with meniscal tears and knee osteoarthritis who are randomized to physical therapy (PT) in trials comparing PT to arthroscopic partial meniscectomy (APM) to cross over from nonoperative therapy to APM?
- Do those who cross over to APM receive symptom relief that’s comparable to those originally randomized to APM?
After careful multivariate analysis of 48 patients who crossed over in the MeTeOR trial (representing 27% of those originally randomized to PT), the authors identified two factors associated with a higher likelihood of crossover: a baseline WOMAC Pain Score of ≥40 and symptom duration of <1 year. The authors also found that patients who crossed over to APM were just as likely to experience improvement in pain scores as those originally randomized to APM.
From a research standpoint, the authors suggest that future investigators may wish to make “special efforts” to keep patients who present with severe pain and relatively short symptom duration in nonoperative therapy. Clinically, Katz et al. say the findings “underscore the emerging treatment recommendation…to try a PT regimen before opting for APM.”
JBJS Reviews Editor’s Choice–Treating ACL Injuries
One of the observations that I have made during my years in academic medicine is that the more popular a topic appears to be in the literature, the less likely we are to really understand it. After all, if we need to write about it so much, it must mean that there is still much to learn. This certainly seems to be the case with regard to injuries of the anterior cruciate ligament (ACL). ACL injuries are among the most common injuries sustained in the United States. Over 100,000 ACL reconstructions were performed in the United States in 2006, and the annual rate has continued to increase over time. Although some patients have achieved good results after nonoperative treatment, a survey of the American Orthopaedic Society for Sports Medicine showed that the majority of respondents used nonoperative treatment for fewer than 25% of their patients with ACL injuries.
Noyes et al.1 described the so-called “rule of thirds.” According to this rule, one-third of patients with an ACL injury will compensate well with nonoperative treatment (copers), one-third will avoid symptoms of instability by modifying activities (adapters), and one-third will require operative reconstruction (noncopers). Unfortunately, there does not seem to be any way to predict which group an individual patient will fall into. Thus, there is still substantial ambiguity in determining which patients are most likely to benefit from early intervention with ACL reconstruction following injury.
In this month’s issue of JBJS Reviews, Secrist et al. used the literature to perform a comparison of operative and nonoperative treatment of ACL injuries. They noted that only 3 randomized controlled trials have compared operative and nonoperative treatment of ACL injuries and that 2 of those studies involved the use of ACL suturing as opposed to more modern forms of reconstruction. The third study involved only 32 patients. All studies had substantial methodological limitations. The authors concluded that there have been no Level-I studies comparing ACL reconstruction with nonoperative treatment.
In their review article, Secrist et al. attempted to define and evaluate the available data on the natural history of nonoperatively treated ACL injuries and to determine how the functional outcomes and injury risks associated with nonoperative treatment compared with those associated with reconstruction. Moreover, they sought to define prognostic factors and rehabilitation protocols associated with successful operative outcomes. Finally, they compared the outcomes following early versus delayed ACL reconstruction.
However, by the end of the article, one gets the feeling that the authors have “come full circle.” The authors summarize their findings by saying that some patients can cope with a torn ACL and return to preinjury activity levels, including participation in pivoting sports. On the other hand, patients who have an ACL injury along with a concomitant meniscal injury are at increased risk for osteoarthritis, and it is unclear what effect reconstruction of an isolated ACL has on future osteoarthritis risk in ACL-deficient patients who are identified as “copers.”
I suspect that we will continue to see articles on this topic for many years to come. In light of the “rule of thirds” and the additional impact of meniscal injury, the allocation of a particular patient to operative or nonoperative treatment remains unclear.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
Reference
- Noyes FR, Matthews DS, Mooar PA, Grood ES. The symptomatic anterior cruciate-deficient knee. Part II: the results of rehabilitation, activity modification, and counseling on functional disability. J Bone Joint Surg Am. 1983 Feb;65(2):163-74 Medline.
Nauth/McKee VideoWins JBJS EST Editor’s Choice Award
To celebrate the launch of “Key Procedures” in October, JBJS Essential Surgical Techniques (EST) invited authors to enter their videos in a contest for the Editor’s Choice Video Award. We are pleased to announce that Aaron Nauth and Mic
hael D. McKee have won the inaugural Editor’s Choice Video Award for their video article “Open Reduction and Internal Fixation of Both-Bones Forearm Fractures.” This video is now live on JBJS Essential Surgical Techniques, with complimentary access.
“Key Procedures” videos offer orthopaedic surgeons succinct 15- to 20-minute, peer-reviewed videos from experts in a variety of subspecialty areas. These videos focus on performing core orthopaedic procedures such as meniscal root repairs, direct anterior hip exposure for total hip arthroplasty, and proximal tibial valgus osteotomy .
JBJS Essential Surgical Techniques is offering free access to “Key Procedures” videos for a limited time. Starting in March 2016, the videos will be viewable only by JBJS EST subscribers.
Meniscal Transplants in Young Patients: Great While They Last
Meniscal transplantation is often recommended after total meniscectomy for patients younger than 50 who remain symptomatic and show articular cartilage deterioration. But for how long are these transplants effective?
That’s what Noyes et al. attempt to answer in a survivorship analysis in the August 5, 2015 Journal of Bone & Joint Surgery. Extending the follow-up from a JBJS study they published in 2005, the authors tracked 40 cryopreserved menisci implanted into 38 patients for an average of 11 years. They measured transplant survival in two distinct ways:
- In terms of symptom-driven endpoints, including transplant removal, revision, or tibiofemoral compartment pain
- In terms of additional asymptomatic “worst-case” endpoints, including grade-3 signal intensity, extrusion (>50% of meniscal width), evident meniscal tear (per MRI or physical examination), or radiographic loss of joint space.
Using Kaplan-Meier survivorship analyses, Noyes et al. estimated transplant survival according to the first set of criteria as follows:
- 88% at 5 years
- 63% at 10 years
- 40% at 15 years
Using the more clinically stringent worst-case criteria, the authors estimated transplant survival as follows:
- 73% at 5 years
- 48% at 10 years
- 15% at 15 years
From these numbers, the authors conclude that “most (if not all) meniscal transplants will undergo a deleterious remodeling process at different time periods postoperatively.” They therefore stress that “patient candidates…should be advised that the procedure is not curative.”
Nevertheless, Noyes et al. emphasize that meniscal transplantation provides many patients with substantial short- and medium-term improvements in knee pain and function and that “there are patients who demonstrate worst-case imaging findings who remain relatively asymptomatic for several years.”
Ultimately, the authors say this study gives clinicians “reasonable survival percentages with regard to the potential to delay the necessity for subsequent major procedures.”
Good Grip Is Key to All-Inside Meniscal Repair
Many meniscus-preserving arthroscopic treatments for meniscus tears have evolved in recent years, including all-inside repairs. Advantages of all-inside techniques include shorter surgical times and reduced risk of damage to neurovascular tissues. Potential drawbacks include risks of local soft-tissue irritation, chondral injury, synovitis, and implant migration or breakage.
One recent generation of all-inside devices, known as FAST-FIX, consists of two polymer anchors connected by a nonabsorbable polyethylene suture in a preloaded delivery needle. In the July 22, 2015, JBJS Case Connector, Rauck et al. presented two cases in which FAST-FIX anchors came loose postoperatively, causing patients to develop knee pain and mechanical symptoms within two to six months after surgery.
To shed additional light on the anchor pullouts described by Rauck et al., we posted a “Watch” article and spoke with Tim Spalding, FRCS, consultant orthopaedic surgeon at the University Hospital in Coventry, England. Dr. Spalding has used FAST-FIX as his main meniscal-repair system for several years.
To minimize potential risks, Dr. Spalding encouraged surgeons to use the supplied slotted cannula when inserting the FAST-FIX delivery needle. “The slotted cannula helps you manipulate the meniscus and steer the needle to exactly where you want it,” Dr. Spalding said.
Perhaps the most important key to success with FAST-FIX is using it in areas of the meniscus that provide strong holding tissue. According to Dr. Spalding, the best grip site for FAST-FIX anchors is the posterior third of the medial meniscus, while tears of the lateral meniscus, especially those near the popliteal hiatus, represent the biggest grip-hold challenge.
“Anchors are not the magic fix some surgeons think they are,” Dr. Spalding concluded. “When they work, they’re simple, fun to use, and you can suture the meniscus in a few seconds, but this major advance might prompt some surgeons to use it in suboptimal situations or with hasty technique.”
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