Why the meniscus changes the OATS picture

For many patients, the conversation with a specialist goes something like this: the cartilage damage needs addressing, but there is also a meniscal problem — does that complicate matters? The short answer is yes, and understanding why helps make sense of everything that follows.

OATS (osteochondral autograft transfer surgery) works by harvesting a small cylindrical plug of healthy bone and cartilage from a low-load area of the knee and pressing it into the damaged site. It is a single-stage procedure best suited to focal defects roughly 1–2 cm² in size, and it transfers genuine hyaline cartilage rather than the inferior fibrocartilage that forms after simpler marrow-stimulation techniques.

The meniscus is the knee's principal shock absorber. It spreads load across the joint surface, reducing peak contact stress on the cartilage beneath. When it is torn, partially removed, or structurally deficient, that protective function is lost — and the compartment where a new cartilage plug sits is exposed to forces substantially higher than normal.

This is the mechanical interdependence that makes combined damage more than simply two separate problems. A well-executed OATS graft placed into a meniscus-deficient compartment is bearing loads it was not designed to resist. The clinical question for patients in this situation is therefore not just whether OATS can technically be performed, but whether it can succeed over the long term when meniscal integrity is compromised or cannot be restored. That question — and the evidence behind it — is what this article addresses.

What long-term OATS data actually shows

Published data give a reasonably clear picture of where OATS stands over time — and where its limits lie. Across long-term follow-up studies, around 72% of patients achieve a successful outcome (Pareek 2016 systematic review), with 10-year graft survival broadly quoted in the range of 72–86%, rising to around 92% in carefully selected cohorts. Those numbers are creditable for a cartilage repair procedure, but they also mean that roughly one in four to one in three patients will experience some degree of structural or clinical failure within a decade.

The pattern of that failure matters. A consistent finding across series is a performance inflection around year five, after which outcomes tend to plateau or, in some patients, decline. Surgeons typically discuss this trajectory at pre-operative counselling so that patients understand the procedure is most likely to provide lasting benefit during the first five years and that longer-term results depend heavily on how well the surrounding joint is preserved. The factors most strongly associated with failure are older age at the time of surgery, a history of prior surgery to the same compartment, and a larger defect area.

The most striking durability evidence to date is a 2025 case report published in JOCR — the only study to include re-arthroscopic visualisation at 18 years post-implantation. The osteochondral plugs on the lateral femoral condyle were fully retained and structurally intact nearly two decades after transplantation. As a single case report, it cannot be taken as typical, but it represents the longest direct visualisation data available and confirms that the hyaline cartilage plug itself is capable of genuine long-term survival when conditions are favourable.

The durability gap between the plug and the meniscal repair

That same 2025 JOCR re-arthroscopy tells a second story — one that matters just as much for combined-procedure planning. While the osteochondral plugs were intact after 18 years, the concurrent lateral meniscus repair had severely failed. Two structures treated at the same operation; two very different outcomes over time.

This divergence reflects a well-documented but often underappreciated difference in long-term durability. Published follow-up data place the overall failure or re-tear rate for meniscus repair at 22–30%. Even with modern techniques applied in patients over 40 — typically the more cautious surgical candidate — roughly 12% of repairs fail at long-term review, with a revision surgery rate of around 9.8%. Stated plainly: somewhere between one in eight and one in three meniscal repairs will not last.

When a repaired meniscus does fail, the consequences extend well beyond the meniscus itself. The protective load-spreading function of meniscal tissue is lost, joint-surface contact stresses rise, and osteoarthritic change accelerates — directly threatening the cartilage graft that may otherwise have decades of structural life remaining. A plug placed with the expectation of lasting benefit can be undermined by the very tissue that was supposed to protect it.

This is why surgeons treating combined pathology must judge meniscal repairability carefully before OATS is confirmed as the cartilage solution. If the repair is unlikely to hold long-term, the planning conversation shifts: alternatives such as meniscal allograft transplantation, or a modified candidacy assessment, need to enter the picture before a cartilage plug is committed to a potentially unsupported compartment.

Candidacy when the meniscus is also damaged

Deciding whether OATS is appropriate starts with a standard set of criteria that apply regardless of meniscal status: the patient is typically under 50, with a BMI below 40, a focal ICRS grade 3–4 chondral or osteochondral defect, a Kellgren-Lawrence osteoarthritis grade of 2 or less, stable ligaments, and no history of inflammatory arthritis or prior joint infection. Conservative management will normally have been tried without adequate relief. These thresholds exist because the graft depends on a joint environment capable of sustaining it — age, body weight, and background OA each affect how the surrounding cartilage and bone respond over time.

When the meniscus is also compromised, two additional questions move to the front: can the meniscal tear be repaired, and where does limb alignment sit?

If the tear is repairable, the preferred approach is to address both problems at the same operation — restoring meniscal hoop stress whilst reconstructing the cartilage defect simultaneously. When significant meniscal tissue has already been lost and repair is not feasible, the assessment becomes more demanding. Nishitani et al. (2020) followed ten patients (mean age 31.7 years) with ICRS grade 4 lateral compartment lesions and established lateral meniscal deficiency who underwent OATS without a realignment osteotomy. The decisive finding was femorotibial alignment: patients whose angle sat between 174° and 178° — close to a neutral mechanical axis — achieved meaningful clinical improvement at roughly six years of follow-up, with IKDC rising from 53.5 to 85.4. Those sitting at 170°–171° either deteriorated clinically or showed progressive valgus drift. In plain terms, if the knee is not close to straight, OATS alone is unlikely to hold in a meniscus-deficient compartment.

Where meniscal tissue loss is substantial and alignment cannot be corrected to near-neutral, meniscal allograft transplantation (MAT) combined with cartilage restoration is generally preferred over OATS in isolation. The decision therefore rests on three meniscal-status categories: a repairable tear (address simultaneously), significant tissue loss with correctable alignment (OATS salvage may be viable with careful patient selection), or significant tissue loss without correctable alignment (MAT plus cartilage restoration is the more appropriate route). Alignment — not meniscal status alone — is the decisive second filter.

Combined surgical strategies for both problems at once

Treating cartilage damage and meniscal injury at separate operations — hoping each heals before the other is stressed — runs against the mechanical logic outlined earlier. When the two structures form part of the same load-sharing unit, surgeons are increasingly opting to address both in a single setting.

The clearest current evidence comes from a 2026 study examining combined transtibial pullout repair for medial meniscus posterior root tears alongside concurrent OATS for focal cartilage defects. At four to six years of follow-up, the combined group achieved KOOS-Symptom and VAS-Pain scores comparable to those seen after unicompartmental knee arthroplasty — a meaningful benchmark in patients where joint replacement had been the default comparator. The rationale is mechanical: pullout repair restores meniscal hoop stress whilst the osteochondral plug reconstructs the focal defect; neither alone addresses both failure modes simultaneously. The OATS subgroup numbered just six patients, however, and that cohort size limits how confidently any conclusion can be drawn.

A 2017 case provides a technique example for a related but distinct problem — an osteochondral lesion of the lateral tibial plateau complicated by meniscal extrusion. Retrograde OATS, which preserves the native articular surface, was combined with arthroscopic meniscal centralisation to restore residual function in the displaced meniscus. Two-year clinical and radiographic results were good, and the case reinforces that when meniscal tissue has not been lost but has lost its position, the surgical plan should reflect that specific mechanical failure rather than treating each structure in isolation.

Combined surgery carries greater operative complexity and recovery demands than either procedure alone. Staged approaches remain appropriate when meniscal repairability is uncertain at the time of initial cartilage assessment, or where tissue loss is extensive enough to favour meniscal allograft transplantation as the primary meniscal strategy. This is an evolving area — larger confirmatory studies are still needed before simultaneous repair can be regarded as a settled pathway rather than a promising but early-stage approach.

What to ask before choosing OATS with a damaged meniscus

Three questions are worth raising explicitly in any pre-operative consultation where both meniscal damage and a cartilage defect are present.

Is the meniscal tear still repairable, or has tissue been lost beyond what repair can restore? The answer determines whether simultaneous repair is an option at all. A depleted meniscus cannot be sutured back to function; where significant tissue is already gone, the discussion shifts to whether meniscal allograft transplantation belongs in the plan alongside cartilage restoration — rather than OATS in isolation.

Where does limb alignment sit? As the Nishitani cohort demonstrated, a femorotibial angle outside the 174°–178° range in a meniscus-deficient knee predicts poor outcomes from OATS alone. Alignment scrutiny in this setting is not a box-ticking formality.

What does the evidence say about the longer term? OA progression data in meniscal-deficiency OATS patients beyond six years does not yet exist, and no large prospective trial has compared combined approaches in a way that would settle the question. Medium-term results — which the published series do support — are not the same as a guaranteed long-term picture, and patients deserve to hear that distinction plainly.

MRI is central to answering all three questions; objective biomechanical load-distribution data, where available, adds precision that imaging alone cannot provide. For patients navigating this assessment, the MSK Doctors team at Sleaford and Grantham accepts combined meniscal and cartilage presentations without a GP referral — appointments can be made directly at mskdoctors.com.

1. [1] A Randomised Prospective Study of Functional Outcomes Between Arthroscopic Reconstruction of ACL with OATS and ACL with Microfracture in Patients with ACL Tear Associated with Osteochondral Damage. (2023). https://doi.org/10.36106/ijsr/5106290 https://doi.org/10.36106/ijsr/5106290
2. [2] Osteochondral Autograft Transplant as a Potential Salvage Procedure for Articular Cartilage Defects of the Lateral Compartment in Lateral Meniscus–Deficient Knees. (2020). https://doi.org/10.1177/2325967120962753 https://doi.org/10.1177/2325967120962753
3. [3] Arthroscopic versus Open Osteochondral Autograft Transplantation (Mosaicplasty) for Cartilage Damage of the Knee: A Systematic Review. (2019). https://doi.org/10.1055/s-0039-1692999 https://doi.org/10.1055/s-0039-1692999
4. [4] Evaluating single-stage cartilage treatments in the knee: A systematic review and meta-analysis of osteochondral autograft transfer surgery (OATS) and minced cartilage repair (MCR) techniques. (2026). https://doi.org/10.1016/j.jor.2025.12.052 https://doi.org/10.1016/j.jor.2025.12.052
5. [5] Osteochondral lesion of lateral tibial plateau with extrusion of lateral meniscus treated with retrograde osteochondral autograft transplantation and arthroscopic centralisation. (2017). https://doi.org/10.1016/j.asmart.2017.01.001 https://doi.org/10.1016/j.asmart.2017.01.001
6. [6] Mid-Term Clinical Outcomes of Pullout Repair Combined with Osteochondral Autograft Transplantation for Medial Meniscus Posterior Root Tears with Focal Cartilage Defects. (2026). https://doi.org/10.3390/bioengineering13030343 https://doi.org/10.3390/bioengineering13030343