Arthroscopic surgery for Osteoarthritis (OA) knee is not a new concept. In fact, in the past 50 years or so, before the widespread acceptance of Total Knee Replacement (TKR), Arthroscopic surgery, along with High Tibial Osteotomy occupied a prominent place in the Orthopaedic surgeon’s arsenal. These surgeries were (and still are) in sync with the socio-cultural requirements of our patients. This is most useful in Asiatic cultures that require squatting for toilet, sitting down on the floor or kneeling for prayers. Walking on uneven surfaces and negotiating staircases, again a prominent requirement in these countries, requires a high degree of proprioception that artificial knees cannot achieve for obvious reasons.
Arthroscopic surgeries for predominantly mechanical symptoms like locking and give-way sensations have always been a success on short-term basis. Unfortunately, long term results of Arthroscopic surgery in OA Knee were not very exciting. This could probably be attributed to the lack of specific criteria (age, activity level, extent of cartilage damage and patient expectations) and available operating instruments at that time.
That was a pre-MRI era, where pre-op diagnosis of extent of cartilage damage was inaccurate. But, for want of anything better to offer to the patient, even Tricompartmental OA underwent Arthroscopic surgery, or sometimes even joint lavage. This approach could not provide expected relief to patients.
Moreover, by today’s standards, the available surgical tools were inefficient and crude, so that a lot depended upon an individual surgeon’s skill. This led to an impression that doing Arthroscopic surgery for OA Knee was not much better than a placebo or worse still same as doing a sham surgery.
When TKR burst upon the scene, a generation of surgeons, at least in India, largely felt that beyond conservative therapy there is only TKR. Even today in academic meetings on OA knee, Arthroscopic surgery and High Tibial Osteotomy are only cursorily discussed.
Has this extreme approach of directly jumping to TKR, once a conservative therapy, irrespective of the age of the patient and condition of all compartments of knee, solved our patients’ problems? Of course not!
There is a huge mismatch between what the patients expect from the surgeons and what they can give them. Instead of modifying our treatment methods to cope up with their socio-cultural requirements, we just impose a ban on a whole set of activities on them.
Recent literature highlights a high degree of dissatisfaction after TKR at an early age, i.e. between 50 to 55 years.
What about the Hiflex design that is supposed to be the panacea for Asiatic knees? Bollars et al in JBJS 2011 has analysed the unsatisfactory results of these implants. Moreover, their longevity claims are based not on actual data but on computerised predictions.
Consider these well-known facts about OA Knee
- Life expectancy today is 75+ years
- Optimal life of primary TKR prosthesis is 12-15 years
- Revision TKR has problems of technique, cost and rehabilitation
- OA knee onset is at 50+ years
Hence, we must find a different solution for these patients between 50-60 years, with failed conservative therapy, demanding good function from their natural knee, at the peak of their professional careers and too early to consider a TKR. If we do a primary TKR not before 60 years, we can hope to avoid a revision TKR for that patient.
Laser assisted Arthroscopic surgery with correction of Biomechanics provides a logical solution to these patients. Laser promises to fill up a huge lacuna in our armamentarium. It has many advantages over the suction-shaver and the radiofrequency apparatus.
Important aspects of using Laser
1) Laser technology is for intra-articular use and therefore used as an Arthroscopic surgical tool. It is not an alternative to Total Knee Replacement. Using this technology does not prevent a TKR, but it has the potential to postpone TKR by a significant period of time. This has valuable implications in the 50-60 age group.
2) This technology should not be viewed as the latest Gizmo in town. Our time-tested tools do retain their value. Using Laser does not make a bad surgeon good, but it can vastly improve the results for a good surgeon if used in a judicious manner.
3) This surgery is NOT indicated in Tricompartmental OA of the Knee, where TKR is still the Gold standard.
Use of Laser in Arthroscopic Surgery of the Knee
Laser technology was first commercialised for military purposes in the 1960s in the U.S. Later on, civilian applications inevitably emerged. There are now more than 10 different types of laser’s available for Medical use.
Laser in general uses the principle that energy is not destructible but convertible from one form into another. Here, electrical energy is converted into light energy. Both theories of light (particle and wave theories) are used, that is a Photon beam of single wavelength is focused onto a target tissue by transmission through a fibre, which is similar to the fibre optic cable used in Endoscopy.
This photon beam interacts with tissues in different ways, producing various effects on them. This has tremendous clinical implications.
The Holmium: YAG LASER works in a liquid medium and hence is suitable for Arthroscopic and Urology applications. This is a Laser beam with wavelength in infrared spectrum, i.e.2100 nm.
Laser energy is transmitted to the target tissue through a fibre of diameter 350 microns, inserted into the joint through a needle probe of diameter 1.8 mm.
Interacting with the intra-articular tissues, it has following effects:
Photothermal effect
When fired from a distance, it can slowly heat up the collagen fibres and denature them. This is of value in shrinkage of loose capsule and ligaments. This is useful for superficial shrinkage of cartilage during cartilage contouring or Chondroplasty
Photoablative effect
Here, a laser fibre in contact with tissues can ablate them by bursting cell walls without formation of free carbon radicles. The fibre-tip temperature is 900 degree-C, so that sealing of surrounding bleeding vessels is easy. This is useful in Synovectomy in Rheumatoid, Psoriasis, Gout and Haemophilia.
This is also useful in Adhesiolysis in post-trauma situations. This can prevent rapid onset of Secondary OA.
Electromechanical effect
Again, a contact beam application is useful in excision of Osteophytes and bony prominences as in Patello-femoral joint and Footballer’s ankle. A major use in OA Knee is for Micro fractures in various situations where multiple areas are involved, as against ACT.
In all these situations, minimal or no residual joint debris is a stand-out feature of LASER usage. Hence, postop synovitis is minimal; morbidity is low, and rehabilitation is faster.
Advantages of using Laser for Arthroscopic Surgery of the Knee
The Holmium: YAG LASER has many advantages over a suction-shaver:
- Minimal tissue debris
- Haemostatic effect
- Minimal collateral tissue damage
- Can do bloodless Microfracture easily
- Osteophyte excision easy
- Can reach crevices of small size knees easily
Simply using LASER will not give good results in Arthroscopic surgery for OA Knee. Three more aspects are equally important:
1) Clinical suspicion of cartilage-at-risk situations
2) Early diagnosis of cartilage damage by MRI scan or Cartigram
3) Correction of biomechanics of weight transmission by High Tibial Osteotomy whenever indicated and feasible
In conclusion, in the 50-60 years age group, where most patients with moderate OA (not Tricompartmental) lie, we must make every effort to increase the life and performance of the natural knee. The least that we owe these patients is to avoid a Revision TKR in their lifetime!