An overview of what we know and what may soon be possible. By Sam Oussedik, Laurence James and Fares Haddad.
Athletes are in no way immune to arthritis; it is a common and perplexing problem among this group. Indeed, despite there being an obvious public health interest in understanding the potential risk of exercise-induced osteoarthrosis (OA) in weight-bearing joints, very little is known about it. This may in part be because of the large number of factors that can contribute to exercise-induced osteoarthrosis (OA), making it difficult to pin down the effect of isolated influences such as exercise or participation in sport.
‘Osteoarthritis’ covers a heterogeneous group of conditions characterised by abnormality in the articular cartilage that underlies bone and joint margins. The disease can be primary, in the absence of any predisposing factors, or secondary, resulting from a known condition. These predisposing conditions fall into four broad categories:
Exercise-induced osteoarthrosis (OA), most commonly of the hip and knee, is a significant and disabling condition for many present and former athletes. The resulting pain and loss of movement can limit function. And while former athletes report symptoms at similar rates to the population in general, they also have higher pain thresholds, which may lead to a relative underestimation of their problems.
We have a poor understanding of the mechanisms by which sportsmen may develop exercise-induced osteoarthrosis (OA). Several models have been proposed. We know, for instance, that sporting activity increases the chances of suffering minor trauma to the articular cartilage. This will alter the way in which forces are transmitted through the joint, risking further damage; and may also alter the force transfer through adjacent joints, putting these in jeopardy.
Sporting activity also increases the chances of damage to intra-articular structures. Taking the knee as an example, a meniscal tear can result in chondral (articular cartilage) damage. Rupture of a knee ligament, such as the anterior cruciate ligament, is also associated with a greater risk of articular damage, although some argue this may be reversed by early reconstruction.
In a study of Swedish men aged 50 to 80 (1), the incidence of exercise-induced osteoarthrosis (OA) of the hip was, at 8%, four times greater among former athletes than among controls of a similar age (2%). Similar but less convincing results were recorded for the knee. Neck and shoulder disorders – which are common problems among recreational sportspeople such as overhead athletes and weight lifters – were less prevalent among former athletes. For all other joints and musculoskeletal disorders the distribution was similar between the groups.
A second study of hospital admissions in Finland for hip, knee and ankle exercise-induced osteoarthrosis (OA), found a greater incidence overall in former international athletes than among controls who had been healthy at the age of 20. This study also identified differences within the athlete groups, with the mean age of first admission being lowest among people who’d played mixed sports (58.2 yrs) and highest in endurance athletes (70.6 yrs). The mean age in the control group was 61.2 years, very close to that for power sports (61.9 years). This result suggests that the increased incidence at least in endurance athletes may be attributable to advanced age-related changes rather than the sport itself (2).
Other studies to determine the relationship between previous lower-limb loading and current self-reported hip and knee disability in elite international athletes have found that these athletes report less hip disability than ‘normal at age 20 control’ subjects. But among team-sport athletes (in particular ball-game activities) there was a higher risk of knee disability. The relationship between vigorous athletic activity and knee function is controversial, because such sports often involve a high risk of knee injury, which is likely to lead to pain, disability and osteoarthritis (3).
We also now know (Gross et al (4)) that the risk of exercise-induced osteoarthrosis (OA) among former elite athletes is similar to that of members of the general population who say they have pursued long-term sporting activity, which suggests that duration may be more significant as a contributory factor than intensity or frequency of training. And although these active groups are exposed to increased risk of hip and knee exercise-induced osteoarthrosis (OA), Gross et al have found that regular moderate jogging in middle age is likely to help maintain physical function.
For the majority of less active exercisers, recreational physical activity seems neither to increase nor decrease the risk of exercise-induced osteoarthrosis (OA) to any marked extent.
Compared with controls of similar age, X-rays of most large joints of former athletes have shown up more frequent signs of exercise-induced osteoarthrosis (OA). This association increases further after adjusting for height and weight differences. Osteophytes (bony growths) are most commonly found in affected knee and hip joints (especially in tennis players) and patello-femoral joint (especially in runners). With the exception of the knee, joint space narrowing was also a common feature in the joints affected (5).
The focus of any treatment is to allow for pain-free participation in sports and activities, so that the patient can continue to enjoy the benefits of regular exercise, and perhaps delay the need for surgery. Rehabilitation plays a key role in all non- operative treatment for arthritis, particularly to restore motion.
A progressive, phased regime is very important. Initially drugs are used, such as non-steroidal anti-inflammatories, with or without the use of ‘cartilage protective’ agents such as glucosamine, to maintain mobility and pain control. Corticosteroid or visco-supplementation joint injections are usually given at this stage.
Physiotherapists may then use sport- specific open, and later closed, kinetic- chain non-weight bearing exercises for the joints involved. These proprioceptive, muscle stretching and strengthening aspects of physiotherapy can have a beneficial effect within three months.
Early arthritis in athletes can be treated with minimally invasive surgery, for instance to remove loose bodies, clean up inflamed and torn tissues, undertake capsular release, and other associated procedures such as rotator cuff repair and decompression. Arthroscopic techniques in many cases enable surgeons to diagnose and symptomatically treat limitations of range of motion and pain, prolonging active careers. Post-operative physiotherapy is very important in all cases.
To help prevent the early onset of degenerative change and restore function, surgery focuses on reconstructing damaged soft tissue. ACL reconstruction, for instance, has become established as an important procedure to restore normal knee biomechanics. Not only does it treat symptomatic instability in the knee, allowing a return to high-level sport, it also improves the chances of avoiding further damage to intra-articular structures such as the menisci, and associated degenerative changes (6).
In cases of advanced degenerative changes associated with an underlying anatomical defect, such as genu varum (bow legs), an osteotomy may be indicated. This has the advantage of stabilising chondral damage and re-establishing normal joint alignment, while conserving bone stock. In the younger patient it allows more function than they could expect from joint replacement surgery.
Joint replacement surgery remains the best treatment for symptomatic exercise-induced osteoarthrosis (OA) of the hip and knee. But active people who have joint replacement should not expect necessarily to return to the same level of sporting activity post-operatively.
Two studies have examined the postoperative prospects for recreational sportspeople after joint surgery. With total hip replacement, patients may expect to return to low-impact sports, such as walking, bowls or aqua aerobics, but they are less likely to be able to carry on doing tennis, jogging or golf (7). The picture is similar for total knee replacement (8).
Newer procedures, such as unicompartmental knee replacement and hip resurfacing may improve the chances of a successful return to a broader range of sporting activities. This has certainly been our experience, with many who are still competing. However, little objective medium-term data exists to confirm this.
Current research is focused on providing a more biological approach to the treatment of exercise-induced osteoarthrosis (OA). Tissue engineering involving the use of stem cells is one avenue: if one views exercise-induced osteoarthrosis (OA) as an imbalance between local tissue destruction and repair, then applying progenitor cells locally allows for a restoration of the pool of cells from which new cartilage can form. This approach has had some success in animal models , and human applications are not too far away.
Advances in implant design may also hold out the promise of better performance after total joint surgery. Newer technologies, such as autologous cultured chondrocyte implantation, tissue engineered cartilage, growth factors and acellular matrices, may significantly alter our ability to manage osteoarthritis with greater success.
Sam Oussedik is clinical and research fellow in orthopaedics at University College London. His primary interest is football
Laurence Jamesis an orthopaedic registrar with a special interest in gene physiology and its effects on human performance
Fares Haddad BSc MCh (Orth) FRCS (Orth) is a consultant orthopaedic surgeon at University College London Hospital and editorial consultant to Sports Injury Bulletin