My Patient Has A Cyclops Lesion!

How the cyclops lesion looks on MRI

Two to three months after her anterior cruciate ligament (ACL) reconstruction, my patient presented with pain at the front of the knee especially when trying to straighten her knee. There is sometimes an audible clunk with the  straightening.

Her quadriceps muscles were weakened and she can't straighten her knee fully. There is often mild swelling too. There is also some soreness at the back of knee in the hamstrings and calf area.

If you haven't read the heading above, would you be able to guess what problem my patient has? There is a 4 percent chance of this happening after an ACL reconstruction.

For those not familiar, a cyclops lesion is usually a localized form of arthrofibrosis (or scar tissue) in the front of the knee joint. The cyclops lesion is a stump of tissue at the front portion of the intercondylar notch, which sits above the tibial tunnel that is drilled for the graft. The cyclops lesion usually gets impinged between the tibial and femur when straightening the leg.

intercondylar notch

How does the cyclops lesion come about? One theory suggest that it may be a remnant of the previous torn ACL stump that remained after surgery. Another theory suggest it may be fibrocartilage formed after drilling the tibial tunnel or from broken graft fibres.

Femur on top of tibia

There is also some evidence to suggest that the cyclops lesion may be a result of inappropriate surgical technique during the ACL reconstruction (Delince et al, 1998). So make sure your choose your surgeon carefully.

So how do we manage the cyclops lesion for the patient? Best way to avoid getting it is to work on regaining full knee extension immediately after the operation.

Once the tell tale signs are present (in the first paragraph of this article), not much else can be done. Yes, you read correctly, there's nothing much a physiotherapist can do. From experience, no amount of pushing, joint mobilizations, exercise or injections etc will help.

The only available option is to refer the patient back to his/ her surgeon to order an MRI to rule out or confirm the cyclops lesion. If it is a cyclops lesion, the best and actually only option is to have a knee arthroscopy and remove that naughty piece of scar tissue. This has shown to have good results (Sonnery-Cottet et al, 2010), especially if aggressive straightening commences after removing the cyclops lesion.


Reference

Delince P, Descamps PY et al (1998). Different Aspects Of The Cyclops Lesion Following Anterior Cruciate Ligament Reconstruction: A Multifactorial Etiopathogenesis. Arthroscopy. 14(8): 869-876.

Sonnery-Cottet B, Lavoie F et al (2010). Clinical And Operative Characteristics Of Cyclops Syndrome After Double-bundle Anterior Cruciate Ligament Reconstruction. Arthroscopy. 26(11): 1483-1488.

Picture from kneeguru.co.uk

Mosaicplasty For Articular Cartilage Injuries

Last week we discussed the microfracture technique for articular cartilage injuries. Many of my patients who read the article commented that they did not realize it was such a serious condition. Yes, indeed, having an articular cartilage injury is worse than tearing your anterior cruciate ligament (ACL). The lengthy rehabilitation makes it much worse.

Generally, the microfracture technique works well only for the smaller lesions (less than 3 cm). If the size of the defect is larger, the surgeon would usually perform mosaicplasty or autologous chondrocyte transplantation (ACT). The latter procedure works better if there is a "kissing lesion" (defect on both joint surfaces).

I wrote that the microfracture technique was made popular by Richard Steadman. For mosaicplasty, it is Professor Laszlo Hangody from Hungary who has probably performed the most procedures and published the most articles on the topic.

Harvesting the bone plugs

Mosaicplasty is a technique in which small bone plugs with healthy hyaline cartilage are taken and then transplanted to cover the defect in the damaged area. The bone plugs are usually taken from an area that is non weight bearing to cover the defect in the affected area. The end result ends up looking like mosaic tiles, hence the name mosaicplasty.

Here's a closer look

The hope is that the body will not miss the taken parts and it can be used where it is needed. Over time, the holes in that part of  bone that is taken will fill with bone and scar tissue. The bone plugs can be from the patient or from fresh cadavers.

The above diagram shows the procedure done on a patient's knee, but it can be done on the ankle, hip and other weight bearing articular surfaces too.

A similar technique to mosaicplasty is Osteochondral Autograft Transfer System or (OATS). The bone plugs used in OATS are usually larger and usually only one or two plugs are needed to fill the area of damage.

See the gaps in between the bone plugs?

In the above pictures, you can see that there are still gaps between the cylindrical bone plugs. This is the main problem with this particular technique. The defect is not filled completely and the gaps normally fill up with fibrocartilage. There is then a worry about how this holds up over time, especially if the patient is keen on returning to sports.

Recently, there has been an improvement/ modification to this technique. A group of researchers, inspired by the honey comb structure of a beehive of honey bees decided to use hexagonal shaped bone plugs instead of the cylindrical ones used previously.

No more gaps?

This is to eliminate the gaps while performing the procedure. The authors named it hexagonal osteochondral graft system (HOGS). Early outcomes of HOGS seemed comparable to mosaicplasty and promising at this stage although further follow up needs to be done.

Advantages of mosaicplasty  are that only one operation is needed (compared to two in ACT) and hence lower cost and less down time. There is less risk of disease transmission and there is a high percentage of hyaline cartilage for the damaged surface.

These procedures require the physiotherapist treating the patient to have knowledge of the biology of articular cartilage and the factors that may influence degradation and repair. The physiotherapist needs to know the nature, location, size of lesion and the surgical procedure performed.

Rehabilitation should address the patient's impairments and functional limitations without jeopardizing healing of the lesion.

I remember back in 1999, as a young physiotherapist a patient told me he had mosaicplasty done and I had asked him what it was. That piqued my interest in articular cartilage injuries and especially so when I later had to have a microfracture procedure done on my right knee in 2003. That also was why I did postgraduate work in that area as I desperately wanted to compete again.

My next post will be on the autologous chondrocyte transplantation/ implantation (ACT) procedure.

References

Erol MF and Karakoyun O. (2016). A New Point Of View For Mosaicplasty In The Treatment Of Focal Cartilage Defects Of Knee Joint: Honeycomb Pattern. SpringerPlus. 5(1): 1170. DOI: 10.1186/s40064-016-2796-y.

Gracitelli GC, Moraes VY et al (2016). Surgical Interventions (Microfracture, Drilling, Mosaicplasty And Allograft Transplantation) For Treating Isolated Cartilage Defects Of The Knee In Adults. Cochrane Database of Systematic Reviews. Issue 9. Art. No CD10675. DOI: 10.1002/4651858.CD010675.pub2.

Hangody L and Balo E (2011). Autologous Osteochondral Mosaicplasty. In Sanchis-Alfonso V. (eds). Anterior Knee Pain And Patellar Instability, London.

My Patient Had A Microfracture Done In The Knee

Articular cartilage is white, with the bone exposed

A fellow physiotherapist who works in a hospital came to see me after a microfracture procedure done on her knee. There was a grade 4 articular cartilage defect on her knee and this led to swelling and pain while climbing stairs and after weight training.

Outerbridge articular cartilage classification

All of us have a layer of articular cartilage covering the ends of  our bones, especially the joint surfaces. It is normally tough and resilient. This helps to protect the joint during load bearing and reduce friction during movement. Injury or damage to the articular cartilage can result from trauma (during sports) or from daily wear and tear. As articular cartilage has poor/ no blood supply, it does not heal well after injury.

There is no standard and uniform approach to managing articular cartilage injuries in the knee. Left untreated it can progress to significant joint destruction. The patient may then need a total knee replacement in the worse case scenario.

Treatment options include microfracture, arthoscopic drilling, mosaicplasty and chondrocyte transplantation to restore the joint surface.

A microfracture technique is where the surgeon performs key hole surgery to cause bleeding on the bone surface to promote healing (picture below). It is performed by the surgeon puncturing holes in the subchondral bone layer to allow bleeding to occur.  After the blood clots and heals, a layer of fibrocartilage is formed. This technique was first made popular more than 20 years ago by Dr Richard Steadman from Vail, Colorado who has since retired.

My patient had the microfracture procedure done (in the picture above) and as you can imagine, the rehabilitation to return to sport can be lengthy. There is usually a period of non weight bearing for the first six to eight weeks to allow healing while using continuous passive motion (CPM)  machine at night. Use of the CPM machine is to stimulate movement to enable nutrition in the articular cartilage since the patient is non weight bearing. Yes, correct movement and some loading forces are necessary for our articular cartilage to recuperate.

Most surgeons here do not usually suggest use of the CPM machine after performing the microfracture technique which I feel is critical in order for optimal healing to occur in the articular cartilage.

Lots of patience and consistency are required by the patient and physiotherapist to slowly regain functional range of movement and strength before any return to sport work can be done.

Fortunately, articular cartilage injuries are my area of interest having had them myself (and requiring 3 knee surgeries) and my postgraduate research was in this area.

I'll write more about mosaicplasty and and the chondrocyte transplantation procedure in the next post. Stay tuned.

References

Hurst JM, Steadman JR et al (2010). Rehabilitation Following Microfracture For Chondral Injury In The Knee. Clin Sports Med. 29(2): 257-265. DOI: 10.1016/j.csm.2009012.009.

Steadmann JR, Rodkey WG et al (1997). Microfracture Technique For Full-thickness Chondral Defects. Oper Tech Orthop. 7:300-304.

Here's what the surgeons use to cause bleeding in the bone