A Degenerative Knee:
How to Keep Them Physically Active

William Stanish M.D., F.R.C.S.(C), F.A.C.S.
Professor of Surgery, Dalhousie University
Halifax, Nova Scotia, CANADA

The Philosophy
The disease osteoarthritis is described as a generally progressive loss of articular cartilage, accompanied by attempted repair and remodelling. Notwithstanding the process of aging, hyaline cartilage becomes degenerative basically under two conditions. (Ref: Felson DT. Epidemiology of Hip and Knee Osteoarthritis. Epidemiology Review, 1988; 10:1-28.)

1. Hyaline cartilage overload.
   
   In situations of disturbed joint mechanics (e.g., genu varus), hyaline cartilage degeneration can occur depending on the degree of external demand. Articular cartilage possesses a very high tolerance for mechanical loading and can tolerate stresses up to but not below 25 n/m2. Most athletic physical activities, such as running, trigger articular surface stresses in the range of 4 to 9 n/m2. With severe single impact loads, insult to the chondrocyte and/or matrix will prompt initial blistering of the joint surface. If the mechanical disturbance is not rectified, then progressive joint surface fissuring, followed by erosion, can occur. (Ref: Buckwalter JA, Mankin HJ. Articular Cartilage 11: Degeneration and osteoarthritis, repair, regeneration, and transplantation. JBJS 79A: 612-632, 1997.)
   
2. Hyaline cartilage underloading.
   
   In the clinical situation of forced immobilization and/or underload, an unfavourable circumstance exists for hyaline cartilage. This clinical situation occurs far less frequently than overload but does require the same attention to therapeutic intervention. In the face of a significant injury to the hyaline cartilage, a period of immobilization after such injury may prevent degeneration. Forced motion and loading may be counterproductive in attempting to achieve hyaline cartilage restoration. (Ref: Williams JM, Brandt KD. Immobilization Ameliorates Chemically Induced Articular Cartilage Damage. Arthritis and Rheumatism, 27:208-216, 1984. Buckwalter JA. Activity Versus Rest in the Treatment of Bones, Soft Tissue and Joint Injuries. Iowa Orthopaedic Journal, 15:29-42, 1995.)

The Treatment
A successful treatment program must address and deal effectively with:

1. Controlling the pain component
   
   (Ref: Brooks PM, Day RO. Non-Steroidal Anti-Inflammatory Drugs - Differences and Similarities. New England Journal of Medicine, 1991, 324:1716-1725.)
   
   In most cases of early degenerative joint disease (Grade 1/Grade II) it is usually necessary to address the intermittent exacerbation of joint pain. Invariably, there is an inflammatory component that when treated successfully, enters into remission. The treatment for the pain can be effective with such simple techniques as activity modification, analgesia and/or physical modalities. (Ref: Panush RS. Is Running Associated With Degenerative Joint Disease? JAMA 255:1152-1157, 1986.)
   
2. Controlling the mechanical component
   
   Invariably, degenerative joint disease within the knee is associated with a disturbed mechanical component. If, in fact, the pain component is not rectified with a simple medication and/or modality, then the introduction of strategies to alter the disturbed mechanics are essential.
   
   (Ref: Buckwalter JA, Rosenburg IC, Hunziker EB. Articular Cartilage: Composition Structure Response to Injury and Methods of Facilitating Repair. In: Articular Cartilage in Knee Joint Function: Basic Science and Arthroscopy, (ed) J.W. Ewing, Raven Press, New York, 1990, pp 19-56. Fundamentals of Articular Cartilage and Meniscus Biomechanics, Mow VC, et al. Articular Cartilage in Knee Joint Function; Basic Science and Arthroscopy; (ed) JW Ewing, Raven Press, New York, pp 1-18. Brand Ra; Joint Lubrication, (ed) Albright and Brand; The Scientific Basis of Orthopaedics, 2nd ed., Appleton & Lang, 1987, pp 373-386. Biomechanical Gait Analysis of Morbidly Obese Women. ElHawary R, Stanish WD, Kozey J, Kirby RL, McLeod DA, Perey BJ. (unpublished).)

Interventions to Control Pain in the Degenerative Athletic Knee

1. Local Pain Control
   
   1. Cryotherapy
      
      The intermittent use of ice, particularly on the knee joint, has proven most successful in controlling the exacerbation (inflammatory phase) within the degenerative athletic knee. The simple process of applying a packet of frozen vegetables for a 20- to 30-minute period can be as effective as the commercially available products that are more refined. (Ref: Melzack R, Wall Pd. Pain Mechanisms: A New Theory. Science 150, pp971-979, 1965. Waylonis GW. The Physiological Effects of Ice Message. Archives Physical Medicine Rehabilitation, 48:47-52, 1967.)
      
   2. Intra-articular Cortisone Injections
      
      Although an extremely useful technique, the intermittent use of intra-articular cortisone should be deployed with caution. The potential risks of provoking hyaline cartilage degeneration, the hazards as they relate to joint infections, and the limitations of cortisone should be fully discussed and disclosed with the patient. (Ref: Postume P, Stanish WD. The Intra-articular and Periarticular Use of Corticosteroid in Knee and Shoulder. The Clinical Journal of Sports Medicine, Vol. 4, No. 3, pp 155-159, July 1994.)
      
   3. Electrical Stimulation
      
      The intermittent use of transcutaneous electrical stimulation (TENS) has proven to be a popular modality for the reduction of pain. Acupunture, acupressure and similar type interventions could be explored. They are uniformly non-invasive and thus extremely safe and patient friendly. (Ref: Stanish WD, Curwin S. Special Techniques in Rehabilitation. In: The Crucial Ligaments. (eds) JA Feagin, Jr, Churchill Livingstone, New York, Edinburgh, London, Melbourne, pp 773-781, 1988.)
      
2. Systemic
   
   1. Analgesic Pain Control
      
   2. Non Steroidal Anti-inflammatories
      
      Very frequently the deployment of a simple pain medication can allow the athlete to continue to participate in the face of a degenerative knee. The patients are usually very compliant when it comes to the intermittent use of a medication rather than accepting drugs that must be used over a long period of time, i.e., non-steroidal anti-inflammatories. Currently there is some compelling evidence that suggests that anti-inflammatory medications used over a prolonged period of time function as an anti-metabolite and may, in fact, disturb the normal reparative process. (Ref: Non Steroidal Anti-Inflammatory Drugs. (ed) Lewis Lewis AJ, Furst DR, New York, Publisher: Marcel Dekker, 1987, pp 71-88. Management of Inflammation of the Knee; Stone J, Zarins B. In: Articular Cartilage in Knee Joint Function; Basic Science in Arthroscopy, (ed) JW Ewing, Raven Press, pp 167-189. Simon LS. Actions in Toxicity of Non Steoidal Anti-Inflammatory Drugs. Curr. Opin. In Rheumatology, 1995, 7:159-166. Brooks PM, Day RO. Non-Steroidal Anti-Inflammatory Drugs - Differences and Similarities. New England Journal of Medicine, 99:324, pp 1716-1725.)

Interventions to Control Mechanical Overload
in the Degenerative Athletic Knee

1. Reduction in body weight
   
   Ongoing research suggests a significant reduction in joint reaction force with the reduction in body weight. This is particularly true if, in fact, the athlete suffers with disturbed joint mechanics, i.e., genus varus. (Ref: Biomedical Gait Analysis of Morbidly Obese Women, ElHawary R, Stanish WD, Kozey J, Kirby RL, McLeod DA, Perey BJ. (unpublished). Newton PM et al. The Effect of Life Long Exercise on Canine Articular Cartilage. Am. J. Sports Medicine, 25:282-287, 1997. Falston DT, et al. Weight Loss Reduces the Risk for Systematic Knee Osteoarthrosis in Women. The Framingham Study; Annals of Internal Medicine; 116(7):535-539, 1992)
   
2. Activity and footwear modification
   
   (Ref: Cooper C et al. Mechanical and Constitutional Risk Factors for Systematic Knee Osteoarthritis: Differences Between Medial, Tibial, Femoral and Patello-Femoral Disease. J. of Rheumatology, 21:307-313, 1994. Buckwalter JA, Lane NE. Athletics and Osteoarthritis. AJSM 1997; 25(6):873-881.)
   
3. Knee bracing
   
   The unloader brace has proven to be most popular and readily accepted by patients. The science may be soft, however ongoing research provides convincing evidence of the ability to normalize joint mechanics with the use of knee and foot orthoses. (Ref: Application of a Lateral Heel Wedge as a Non Surgical Treatment for Varus Gonarthrosis; Giffin JR, Stanish WD, MacKinnon S, MacLeod DA, Journal of Prosthetics and Orthotics, 1995; 7(1). Effective Axial Alignment of the Lower Extremity on Articular Cartilage of the Knee; Coventry M. In: Articular Cartilage and Knee Joint Function, Basic Science in Arthroscopy; (ed) JW and Raven Press, pp 311-317. Valgus Knee Bracing for Medial Gonarthrosis; Horlick SJ, Loomar RL. Clinical Journal of Sports Medicine, 1993; 251-255. Use of Lateral Heel Wedges in the Treatment of Medial Osteoarthritis of the Knee; Keating EM, et al. Orthopaedic Review, 1993, 12:921-924. Functional Knee Braces and Dynamic Performance: A Review. Kramer JF, et al. Clinical Journal of Sports Medicine: 7:32-39, 1997.)

The Role of Surgery

1. Arthroscopic excision of damaged cartilage with penetration of subchondral bone.
   
   (Ref: Ewing JW. Arthroscopic Treatment of Degenerative Meniscal Lesions and Early Degenerative Arthritis of the Knee. In: Articular Cartilage and Knee Joint Function; Basic Science and Arthroscopy, pp 137-145, (ed) JW Ewing, New York, Raven Press 1990. Johnson LL. Arthroscopic Abrasion Arthroplasty. In: Operative Arthroscopy. (ed) JB McGinty, Raven Press, Philadelphia 1996; 427-446.)
   
2. Perichondral Grafts
   
   (Ref: Hommings GN et al. Perichondral Grafting for Cartilage Lesions of the Knee. JBJS 72B:1003-1007, 1990)
   
3. Autologous Chondrocyte Transplantation
   
   (Ref: Brittberg et al. Treatment of Deep Cartilage Defects in the Knee with Autologous Chondrocyte Transplantation. New England Journal of Medicine, 1994; 331:889-895.
   
4. Allograft
   
   (Ref: Gross AE. Fresh Small Fragment Osteochondral Allografts Used for Post Traumatic Defects in the Knee Joint. In: Biology and Biomechanics of the Traumatized Synovial Joint: The knee as a model. Rosemont, Illinois: American Academy of Orthopaedic Surgeons, 1992; 123-141.)
   
5. Osteotomy
   
   (Ref: Insall et al. High Tibial Osteotomy for Varus Gonarthrosis - A Long Term Follow-Up Study. JBJS, Sept. 1984; 66A:1040-1048.)
   
6. Total Knee Arthroplasty
   
   (Ref: Too many to cite.)

Potential Disasters

1. Treating the pain component without adjusting the disturbed knee mechanics.
2. Performing surgery without exhausting all non surgical measures. The presence of medial compartment gonarthrosis does not justify a surgical intervention until the patient has been fitted with a proper knee orthosis, has altered their activity, and has been placed on a program of NSAID/analgesics prior to their athletic event.
3. Under estimating the nature of the disease and/or the severity of the arthritic process. It is disastrous to consider a surgical procedure designed to unload a compartment of the knee when, in fact, the joint surface facing new stresses is not healthy, thus unable to accept the new load. (Ref: Oxford Textbook of Sports Medicine; (ed) Mark Harries, Clyde Williams, William D. Stanish, Lyle J. Micheli; Oxford Medical Publications, 1994. The Articular Cartilage and Knee Joint Function; Basic Science and Arthroscopy, (ed) J. Ewing, Raven Press, 1990.)