You are here

Article Text

Article menu

Download PDFPDF

Reviews
Prevention and management of knee osteoarthritis and knee cartilage injury in sports
  1. Hideki Takeda1,2,
  2. Takumi Nakagawa2,
  3. Kozo Nakamura2,
  4. Lars Engebretsen1
  1. 1Oslo Sports Trauma Research Center, Oslo, Norway
  2. 2Department of Orthopaedic Surgery, The University of Tokyo, Tokyo, Japan
  1. Correspondence to Dr Lars Engebretsen, Oslo Sports Trauma Research Center, Sognsveien 220, PB 4014 Ullevaal Stadion, 0806, Oslo, Norway; lars.engebretsen{at}medisin.uio.no

Abstract

Articular cartilage defects in the knee of young or active individuals remain a problem in orthopaedic practice. These defects have limited ability to heal and may progress to osteoarthritis. The prevalence of knee osteoarthritis among athletes is higher than in the non-athletic population. The clinical symptoms of osteoarthritis are joint pain, limitation of range of motion and joint stiffness. The diagnosis of osteoarthritis is confirmed by the symptoms and the radiological findings (narrowing joint space, osteophyte formation and subchondral sclerosis). There is no strong correlation between symptoms and radiographic findings. The aetiology of knee osteoarthritis is multifactorial. Excessive musculoskeletal loading (at work or in sports), high body mass index, previous knee injury, female gender and muscle weakness are well-known risk factors. The high-level athlete with a major knee injury has a high incidence of knee osteoarthritis. Cartilage injuries are frequently observed in young and middle-aged active athletes. Often this injury precedes osteoarthritis. Reducing risk factors can decrease the prevalence of knee osteoarthritis. The prevention of knee injury, especially anterior cruciate ligament and meniscus injury in sports, is important to avoid progression of knee osteoarthritis.

http://dx.doi.org/10.1136/bjsm.2010.082321

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Osteoarthritis is the most common musculoskeletal disease and is responsible for decreasing the quality of life among young, active athletes as well as older people.1 The number of people who are affected by osteoarthritis is increasing due to the increasing age of the population. Obesity, excessive stress to the knee (at work or in sports), previous knee injury and muscle weakness around the knee are known risk factors.2,–,5 In analysing preventive possibilities, these risk factors are very important.

    The aim of this review is to evaluate the prevalence of knee osteoarthritis and the relationship between sports activity and osteoarthritis, and furthermore to summarise the prevention and treatment of knee osteoarthritis and cartilage injury in sports, in order to reduce the increasing impact of knee osteoarthritis.

    Prevalence of knee osteoarthritis in sports

    The prevalence of knee osteoarthritis increases with age.1 Symptomatic knee osteoarthritis occurs in 10–38% people aged 60 years or older.6,–,8 This number is increasing due to the ageing of the population. In professional and recreational athletes, the prevalence of knee osteoarthritis depends on the intensity, frequency and level of sports event (table 1).

    View this table:
    Table 1

    The prevalence of knee osteoarthritis in sports

    The prevalence of knee osteoarthritis among former soccer players is 19–29%, long distance runners 14–20% and weight lifters 31%.9,–,13 There are some limitations in these studies. Previous studies that showed the relationship between the sports event and the prevalence of knee osteoarthritis have various definitions and criteria for osteoarthritis, the selection of athletes and the method of analysis.

    Definition of knee osteoarthritis

    Osteoarthritis is a group of diseases in which the homeostasis of articular cartilage chondrocytes, extracellular matrix and subchondral bone is damaged mechanically and biologically.14 Although osteoarthritis may be initiated by multiple factors, including genetic, metabolic and traumatic, they involve all of the tissues of the joint.14 Osteoarthritis includes morphological, biochemical, molecular and biomechanical changes of both cells and matrix, which leads to softening, fibrillation and ulceration, loss of articular cartilage, sclerosis and eburnation of subchondral bone, osteophytes and subchondral cysts.14 Clinical osteoarthritis is characterised by joint pain, tenderness, limitation of movement, crepitus, occasional effusion and variable degrees of inflammation. Most physicians diagnose knee osteoarthritis not only by the symptoms, but by the radiological findings. The usual radiographs are read according to the Kellgren and Lawrence (K&L) classification: grade 0, no changes; grade 1, doubtful narrowing of the joint space and possible osteophytic lipping; grade 2, definite osteophytes and possible narrowing of the joint space; grade 3, moderate multiple osteophytes, definite narrowing of the joint space and some sclerosis and possible deformity of the bone ends; grade 4, large osteophytes, marked narrowing of the joint space, severe sclerosis and definite deformity of the bone ends. Conventionally, osteoarthritis has been defined as starting at K&L grade 2 or more.15

    It is important to be aware of the considerable discrepancy between symptoms and radiological findings in osteoarthritis. Fifteen to 81% of patients with radiographic findings have knee pain in a recent systematic review.16 On the other hand, patients who have early painful osteoarthritis might not necessarily have radiographic changes.

    Post-trauma knee osteoarthritis in sports

    Injuries such as knee ligament tears, meniscal injuries and fractures involving articular surfaces have been shown as strong risk factors for knee osteoarthritis.3 10 17,–,19 According to Kujala et al,10 the risk of knee osteoarthritis is increased almost five times in male former top-level athletes with previous knee injuries (OR 4.73). Some studies reported that articular surface incongruities greater than 3 mm increased local contact stress.20 21 Consequently, precise reduction and fracture fixation is needed to avoid knee osteoarthritis after articular surface fracture. Meniscus injury is a risk factor for knee osteoarthritis.3 18 22 Table 2 shows the prevalence of radiological knee osteoarthritis after meniscectomy with long-term follow-up. The mechanical load-sharing function is damaged by injured or resected meniscus.33 The relationship between tear characteristics and the degree of progression of knee osteoarthritis is controversial.29 31 34 35 Some papers reported that preoperative participation in high-level sport is a risk factor for developing radiological knee osteoarthritis.27 29 36 The anterior cruciate ligament (ACL) injury is well known as a risk factor for knee osteoarthritis with or without reconstruction (table 3).37,–,41 Gillquist and Messner42 reported that isolated meniscus tear and subsequent repair, or ruptures of the ACL seemed to increase the osteoarthritis risk 10-fold compared with an age-matched, uninjured population. In addition, Øiestad et al43 showed that the most frequent risk factor for the development of knee osteoarthritis in an ACL-injured athlete was meniscal injury. The prevalence of knee osteoarthritis with combination ACL and meniscus injury was much higher than that with isolated ACL injury. Early diagnosis and effective treatment and ensuring complete rehabilitation after ACL and meniscus injury should decrease the risk of osteoarthritis among sports participants.

    View this table:
    Table 2

    Meniscus injury as a risk factor for knee osteoarthritis

    View this table:
    Table 3

    ACL injury as a risk factor for knee osteoarthritis

    Are the sports themselves causing osteoarthritis?

    Epidemiological studies have showed that participation in some competitive sports increases the risk of osteoarthritis.4 44 45 Moderate exercise has a low risk of leading to osteoarthritis. Furthermore, there is evidence that appropriate exercise reduces disability in the knee.46 Sports activities including high-intensity and direct joint impact as a result of contact with other participants appeared to increase the risk of osteoarthritis.47 Repetitive impact and twisting loads to the knee were also associated with joint degeneration.5 10 48 49 To avoid knee osteoarthritis, participants should pay attention to individual risk factors, frequency and intensity of sports activity.

    The cartilage injury in athletes

    In a study of 993 consecutive arthroscopies in patients with knee pain from Norway, articular cartilage changes were noted in 66% of the knees and isolated, localised cartilage lesions in approximately 20% of the cases.50 Full-thickness cartilage lesions were found in 11% of the knees. Sports participation was the most commonly reported activity (49%). Most of the patients with localised cartilage lesions were in the younger age groups (median age 30 years). The most serious cartilage injuries, ICRS grades III and IV were commonly located at the medial femoral condyle followed by the patella. A single full-thickness area of more than 2 cm2 was observed in 6% of all knees, and half of these patients had a cartilage lesion as their only pathology. Fifty per cent of these larger lesions (grades III–IV and >2 cm2) were localised in the medial femoral condyle and 13% in the femoral trochlea.

    Cartilage treatment should be aimed at restoring normal knee function by the regeneration of hyaline cartilage in the defect, and to achieve a complete integration of the new cartilage to the surrounding cartilage and underlying bone. Recent years have seen several new surgical procedures emerge with the aim to improve function and to create normal cartilage. Unfortunately, clinical studies have been limited by methodological weaknesses. Over the past 10 years, marrow-stimulating procedures such as the microfracture method have been widely used and so far no other procedure has surpassed the microfracture results. The main developmental research has occurred in autologous chondrocyte implantation (ACI), which was first described in 1994.51 Newer techniques combining scaffolds, cells and growth factors have since been developed.52,–,57

    Ninety per cent of rotational injuries to the knee include the so-called bone bruise lesion.58 Follow-up MRI studies of patients with bone bruises suggest that this may lead to degeneration of the cartilage and early arthritis.58 In addition, it has been shown that isolated cartilage injuries may lead to degeneration of the adjacent cartilage.54 These changes may be caused by the abnormally high stresses acting on the rim of the defect. The cartilage surface opposing an isolated cartilage injury often show fibrillation caused by mechanical irritation.60 It is thus suggested that rotational injury to the knee with a bone bruise and subsequent cartilage changes may progress into degenerative arthritis. Moreover, the presence of concomitant injuries (eg, ACL injury or meniscus injury) and malalignment of the lower extremity influences the management of these lesions.48 61,–,63 Below is a brief description of the most used techniques for cartilage treatment.

    Microfracture

    Microfracture as a minimally invasive and simple procedure and is considered the first choice of treatment for patients with previously untreated cartilage defects. This technique has the goal of recruiting pluripotential stem cells from the marrow by penetrating the subchondral bone. The preferable cartilage lesion for this method is relatively small in size (1–2 cm2). Only two controlled, randomised clinical studies exist.64 65 Knutsen et al64 have found good pain relief after 2 years of follow-up in 70–80% of patients, whereas Gudas et al65 found superiority of the osteochondral autologous transplantation over microfracture at 1, 2 and 3-year time points. Furthermore, the Norwegian study comparing ACI with microfracture did not see a deterioration in the clinical results even 5 years after surgery.66 There are few studies investigating the rate of return to sports after microfracture.65 67,–,70 Steadman et al67 reported that 76% of National Football League players returned to play 4.6 more seasons after microfracture. In contrast, Namdari et al68 showed that only 58% of National Basketball Association players were able to return to play at least 1 more season after microfracture. There is an obvious need for studies with more participants.

    Autologous chondrocyte implantation

    Autologous chondrocytes for cell transplantation to regenerate cartilage has been widely used.51 71,–,73 The procedure involves harvesting of 2–300 mg of cartilage through an arthroscopic procedure, followed 2–4 weeks later by an arthrotomy, in which the cells are injected under a cover of periosteum or a synthetic membrane. So far the results of four controlled studies have been published. Bentley et al74 showed that after 19 months, 88% of the patients in the cell group versus 69% in the mosaic group had good to excellent results based on two non-validated scoring systems. Horas et al75 found no differences between cells and mosaicplasty after 2 years. Dozin et al76 also concluded that ACI and mosaicplasty were clinically equivalent and similar in performance. The Norwegian study64 found no difference between cell transplantation and microfractures—both leading to improvement in more than 75% of patients after 2 years.64 There was no significant difference in macroscopic or histological results between the two treatment groups and no association between the histological findings and the clinical outcome at the 2-year time point. Furthermore, the Norwegian study comparing ACI with microfracture did not see a deterioration in the clinical results even 5 years after surgery.66 Hypertrophy of tissue seemed to be the major cause for re-operations after ACI.70 Recently, Saris et al98 published a 3-year follow-up of optimised chondrocyte implantation resulting in improved clinical outcomes compared with microfracture. Kreuz et al79 showed that the rate of return to preinjury levels of sports after ACI among regular or competitive sports athletes was 94% at the 18-month follow-up. The improvement will peak at approximately 2 years, and it does not seem to deteriorate up to 8 years. At the moment the procedure is reserved for patients with large defects on the weightbearing surface of the knee joint. The defects should not be deeper than approximately 5 mm without being bone grafted. ACI may be preferred as a second-line treatment for large defects. Microfracture was recently found to have less favourable results in treating patellofemoral lesions, and ACI may be a better option for trochlear defects.80

    Matrix-guided ACI

    Matrix-guided ACI was invented to improve upon the disadvantages of ACI (hypertrophy of the graft, the uneven distribution of chondrocytes within the defect and the potential for cell leakage). In matrix-guided ACI, chondrocytes are cultured and implanted in scaffold. However, so far the clinical and histological results have not been reported to be better than conventional ACI.81

    Mosaicplasty and osteochondral autologous grafts

    An alternative to biological regeneration of a defect is to replace it with a substitute. Several orthopaedic companies have produced coring drills, which will harvest plugs from areas with relatively less weightbearing such as the intercondylar notch or the most lateral part of the femoral condyle. The plugs are then placed in the defect in predrilled cylinders. The clinical data were first published by Bobic82 and Hangody et al,83 and the results matched those after chondrocyte transplantation by Brittberg et al.51 The recent study by Bentley et al74 showed less encouraging results for this technique, whereas the studies by Horas et al75 and Dozin et al76 reported more optimistic results. Furthermore, the study by Gudas et al65 has shown significant superiority of this technique over microfracture procedures, and showed that the rate of return to sports after mosaicplasty was 93% at an average of 6.5 months. There is an obvious need for longer follow-up studies. The use of this technique is limited only by the size of the defect due to the necessity of harvesting from relatively less weightbearing areas. Synthetic plugs have recently been developed for clinical use as a substitute for autologous graft (True-Fit; Smith and Nephew, Andover, MA, USA).84,–,86 However, no long-term results have been published.

    MSC transplantation

    Mesenchymal stem cell (MSC) transplantation has been introduced to repair cartilage lesions avoiding the disadvantages of other methods. MSC retain both high proliferative potential and multipotentiality, including chondrogenic differentiation potential. A number of animal studies with this method have been reported.87 The use of MSC for cartilage repair is still at the early stage. More clinical studies are needed.

    Treatment of knee osteoarthritis in athletes

    Surgical treatment

    Patients with knee osteoarthritis who are not obtaining adequate pain relief and functional improvement from a combination of rehabilitation and pharmacological treatment are considered for surgical treatments. There is agreement that arthroscopic debridement is not an efficient procedure in osteoarthritis patients.88 For the young and active athletes with symptomatic medial unicompartmental knee osteoarthritis, high tibial osteotomy (HTO) may avoid the progression of disease. The HTO can be done with an open-wedge osteotomy or lateral closing-wedge osteotomy. The medial tibial osteotomy is a popular technique and avoids detachment of the tibialis anterior muscle, the risk of peroneal nerve palsy and loss of correction to the lateral tibial osteotomy.89 For older athletes with knee osteoarthritis, unicompartmental or total knee arthroplasty (TKA) may be considered to improve quality of life as well as some sports activity. Even though HTO and knee arthroplasty are common, there is limited literature reporting on the relationship between sports activity and knee surgery. Only two studies that reported clinical results involving return to sports and heavy works after HTO were found. They showed that 75–91% of patients after HTO were engaged in sports and recreational activities and regained the frequency and duration of sports activities.90 91 In the older patient group, several studies reported that more than 90% of patients after unicompartmental knee arthroplasty and more than 60% of patients after TKA returned to the same level of sports activity as before surgery.92,–,96 Further studies focusing on the appropriate level of sports activity after knee intervention and the prevention of implant problems (prosthetic wear out, loosening) among athletes are clearly needed.

    Prevention of knee osteoarthritis in sports

    As the number of people who have osteoarthritic disease is increasing, the prevention of osteoarthritis is important and necessary. Osteoarthritis has three strong risk factors (excessive musculoskeletal loading, high body mass index and previous knee injury) in which prevention may work. According to Hochberg,97 avoiding squatting and kneeling and carrying heavy loads during work have been associated with a reduction of 15–30% in the prevalence of osteoarthritis in men. Another study showed a significant exposure–response relationship between symptomatic knee osteoarthritis and squatting and kneeling.98 99 Overweight is a risk factor for knee osteoarthritis. Weight reduction reduces not only the symptoms and progression of osteoarthritis, but also the risk of acquiring osteoarthritis.100 101 The Osteoarthritis Research Society International Group strongly recommends that patients with osteoarthritis lose weight and maintain weight at a lower level in overweight patients.102 Maintaining the body mass index at 25 kg/m2 or below would reduce osteoarthritis in the population by 27–53%.97 98 As mentioned, knee injuries such as knee ligament tears, meniscal injuries and fractures involving the articular surfaces is a strong risk factor for knee osteoarthritis. Prevention programmes for sports injury, especially ACL injury, have recently shown encouraging results. Norwegian studies showed that the prevention of ACL injuries was possible with the use of neuromuscular training programmes.103,–,105 According to Felson98 prevention of joint injuries would give an additional 14–25% reduction in the prevalence of osteoarthritis.

    Conclusion

    Ligament, meniscal and cartilage injuries are common in sports. Unfortunately, at present the treatment being surgical or rehabilitation does not seem to avoid the development of osteoarthritis in the knee. Much is happening in research on surgical as well as rehabilitation procedures in this field. Clearly, a greater emphasis on prevention is necessary.

    References

    1. ↵
      1. Woolf AD,
      2. Pfleger B
      . Burden of major musculoskeletal conditions. Bull WHO 2003;81:646–56.
      OpenUrlPubMedWeb of Science
    2. ↵
      1. Toivanen AT,
      2. Heliövaara M,
      3. Impivaara O,
      4. et al
      . Obesity, physically demanding work and traumatic knee injury are major risk factors for knee osteoarthritis – a population-based study with a follow-up of 22 years. Rheumatology (Oxford) 2010;49:308–14.
      OpenUrlAbstract/FREE Full Text
    3. ↵
      1. Cooper C,
      2. Snow S,
      3. McAlindon TE,
      4. et al
      . Risk factors for the incidence and progression of radiographic knee osteoarthritis. Arthritis Rheum 2000;43:995–1000.
      OpenUrlCrossRefPubMedWeb of Science
    4. ↵
      1. Thelin N,
      2. Holmberg S,
      3. Thelin A
      . Knee injuries account for the sports-related increased risk of knee osteoarthritis. Scand J Med Sci Sports 2006;16:329–33.
      OpenUrlCrossRefPubMedWeb of Science
    5. ↵
      1. Felson DT,
      2. Lawrence RC,
      3. Dieppe PA,
      4. et al
      . Osteoarthritis: new insights. Part 1: the disease and its risk factors. Ann Intern Med 2000;133:635–46.
      OpenUrlCrossRefPubMedWeb of Science
    6. ↵
      1. Felson DT,
      2. Naimark A,
      3. Anderson J,
      4. et al
      . The prevalence of knee osteoarthritis in the elderly. The Framingham Osteoarthritis Study. Arthritis Rheum 1987;30:914–18.
      OpenUrlCrossRefPubMedWeb of Science
    7. ↵
      1. Felson DT
      . An update on the pathogenesis and epidemiology of osteoarthritis. Radiol Clin North Am 2004;42:1–9; v.
      OpenUrlCrossRefPubMedWeb of Science
    8. ↵
      1. Dillon CF,
      2. Rasch EK,
      3. Gu Q,
      4. et al
      . Prevalence of knee osteoarthritis in the United States: arthritis data from the Third National Health and Nutrition Examination Survey 1991–4. J Rheumatol 2006;33:2271–9.
      OpenUrlAbstract/FREE Full Text
    9. ↵
      1. Roos H,
      2. Lindberg H,
      3. Gärdsell P,
      4. et al
      . The prevalence of gonarthrosis and its relation to meniscectomy in former soccer players. Am J Sports Med 1994;22:219–22.
      OpenUrlAbstract/FREE Full Text
    10. ↵
      1. Kujala UM,
      2. Kettunen J,
      3. Paananen H,
      4. et al
      . Knee osteoarthritis in former runners, soccer players, weight lifters, and shooters. Arthritis Rheum 1995;38:539–46.
      OpenUrlPubMedWeb of Science
    11. ↵
      1. Turner AP,
      2. Barlow JH,
      3. Heathcote-Elliott C
      . Long term health impact of playing professional football in the United Kingdom. Br J Sports Med 2000;34:332–6.
      OpenUrlAbstract/FREE Full Text
    12. ↵
      1. Drawer S,
      2. Fuller CW
      . Propensity for osteoarthritis and lower limb joint pain in retired professional soccer players. Br J Sports Med 2001;35:402–8.
      OpenUrlAbstract/FREE Full Text
    13. ↵
      1. Chakravarty EF,
      2. Hubert HB,
      3. Lingala VB,
      4. et al
      . Long distance running and knee osteoarthritis. A prospective study. Am J Prev Med 2008;35:133–8.
      OpenUrlCrossRefPubMedWeb of Science
    14. ↵
      1. Kuettner KE,
      2. Goldberg VM
      1. Kuettner KE,
      2. Goldberg VM
      . Introduction. In:Kuettner KE, Goldberg VMeds. Osteoarthritis disorders. Rosemont, IL: American Academy of Orthpaedic Surgeons, 1995:xxi–xxv.
    15. ↵
      1. Kellgren JH,
      2. Lawrence JS
      . Radiological assessment of osteo-arthrosis. Ann Rheum Dis 1957;16:494–502.
      OpenUrlFREE Full Text
    16. ↵
      1. Bedson J,
      2. Croft PR
      . The discordance between clinical and radiographic knee osteoarthritis: a systematic search and summary of the literature. BMC Musculoskelet Disord 2008;9:116.
      OpenUrlCrossRefPubMed
    17. ↵
      1. Rall KL,
      2. McElroy GL,
      3. Keats TE
      . A study of long term effects of football injury to the knee. Mo Med 1964;61:435–8.
      OpenUrlPubMed
    18. ↵
      1. Gelber AC,
      2. Hochberg MC,
      3. Mead LA,
      4. et al
      . Joint injury in young adults and risk for subsequent knee and hip osteoarthritis. Ann Intern Med 2000;133:321–8.
      OpenUrlCrossRefPubMedWeb of Science
    19. ↵
      1. Sutton AJ,
      2. Muir KR,
      3. Mockett S,
      4. et al
      . A case–control study to investigate the relation between low and moderate levels of physical activity and osteoarthritis of the knee using data collected as part of the Allied Dunbar National Fitness Survey. Ann Rheum Dis 2001;60:756–64.
      OpenUrlAbstract/FREE Full Text
    20. ↵
      1. Brown TD,
      2. Anderson DD,
      3. Nepola JV,
      4. et al
      . Contact stress aberrations following imprecise reduction of simple tibial plateau fractures. J Orthop Res 1988;6:851–62.
      OpenUrlCrossRefPubMedWeb of Science
    21. ↵
      1. Huber-Betzer H,
      2. Brown TD,
      3. Mattheck C
      . Some effects of global joint morphology on local stress aberrations near imprecisely reduced intra-articular fractures. J Biomech 1990;23:811–22.
      OpenUrlCrossRefPubMedWeb of Science
    22. ↵
      1. Englund M,
      2. Guermazi A,
      3. Roemer FW,
      4. et al
      . Meniscal tear in knees without surgery and the development of radiographic osteoarthritis among middle-aged and elderly persons: The Multicenter Osteoarthritis Study. Arthritis Rheum 2009;60:831–9.
      OpenUrlCrossRefPubMedWeb of Science
    23. ↵
      1. Jørgensen U,
      2. Sonne-Holm S,
      3. Lauridsen F,
      4. et al
      . Long-term follow-up of meniscectomy in athletes. A prospective longitudinal study. J Bone Joint Surg Br 1987;69:80–3.
      OpenUrlPubMedWeb of Science
    24. ↵
      1. Maletius W,
      2. Messner K
      . Chondral damage and age depress the long-term prognosis after partial meniscectomy. A 12- to 15-year follow-up study. Knee Surg Sports Traumatol Arthrosc 1996;3:211–14.
      OpenUrlCrossRefPubMed
    25. ↵
      1. Burks RT,
      2. Metcalf MH,
      3. Metcalf RW
      . Fifteen-year follow-up of arthroscopic partial meniscectomy. Arthroscopy 1997;13:673–9.
      OpenUrlPubMedWeb of Science
    26. ↵
      1. McNicholas MJ,
      2. Rowley DI,
      3. McGurty D,
      4. et al
      . Total meniscectomy in adolescence. A thirty-year follow-up. J Bone Joint Surg Br 2000;82:217–21.
      OpenUrlCrossRefPubMed
    27. ↵
      1. Chatain F,
      2. Robinson AH,
      3. Adeleine P,
      4. et al
      . The natural history of the knee following arthroscopic medial meniscectomy. Knee Surg Sports Traumatol Arthrosc 2001;9:15–18.
      OpenUrlCrossRefPubMedWeb of Science
    28. ↵
      1. Bonneux I,
      2. Vandekerckhove B
      . Arthroscopic partial lateral meniscectomy long-term results in athletes. Acta Orthop Belg 2002;68:356–61.
      OpenUrlPubMed
    29. ↵
      1. Chatain F,
      2. Adeleine P,
      3. Chambat P,
      4. et al
      . A comparative study of medial versus lateral arthroscopic partial meniscectomy on sf knees: 10-year minimum follow-up. Arthroscopy 2003;19:842–9.
      OpenUrlCrossRefPubMedWeb of Science
    30. ↵
      1. Englund M,
      2. Roos EM,
      3. Lohmander LS
      . Impact of type of meniscal tear on radiographic and symptomatic knee osteoarthritis: a sixteen-year followup of meniscectomy with matched controls. Arthritis Rheum 2003;48:2178–87.
      OpenUrlCrossRefPubMedWeb of Science
    31. ↵
      1. Englund M,
      2. Lohmander LS
      . Risk factors for symptomatic knee osteoarthritis fifteen to twenty-two years after meniscectomy. Arthritis Rheum 2004;50:2811–19.
      OpenUrlCrossRefPubMedWeb of Science
    32. ↵
      1. Englund M,
      2. Paradowski PT,
      3. Lohmander LS
      . Association of radiographic hand osteoarthritis with radiographic knee osteoarthritis after meniscectomy. Arthritis Rheum 2004;50:469–75.
      OpenUrlCrossRefPubMedWeb of Science
    33. ↵
      1. Aagaard H,
      2. Verdonk R
      . Function of the normal meniscus and consequences of meniscal resection. Scand J Med Sci Sports 1999;9:134–40.
      OpenUrlPubMedWeb of Science
    34. ↵
      1. Bolano LE,
      2. Grana WA
      . Isolated arthroscopic partial meniscectomy. Functional radiographic evaluation at five years. Am J Sports Med 1993;21:432–7.
      OpenUrlAbstract/FREE Full Text
    35. ↵
      1. Hede A,
      2. Larsen E,
      3. Sandberg H
      . The long term outcome of open total and partial meniscectomy related to the quantity and site of the meniscus removed. Int Orthop 1992;16:122–5.
      OpenUrlPubMedWeb of Science
    36. ↵
      1. Stehling C,
      2. Lane NE,
      3. Nevitt MC,
      4. et al
      . Subjects with higher physical activity levels have more severe focal knee lesions diagnosed with 3T MRI: analysis of a non-symptomatic cohort of the osteoarthritis initiative. Osteoarthr Cartil 2010;18:776–86.
      OpenUrlCrossRefPubMedWeb of Science
    37. ↵
      1. Neyret P,
      2. Donell ST,
      3. Dejour H
      . Results of partial meniscectomy related to the state of the anterior cruciate ligament. Review at 20 to 35 years. J Bone Joint Surg Br 1993;75:36–40.
      OpenUrlPubMedWeb of Science
    38. ↵
      1. von Porat A,
      2. Roos EM,
      3. Roos H
      . High prevalence of osteoarthritis 14 years after an anterior cruciate ligament tear in male soccer players: a study of radiographic and patient relevant outcomes. Ann Rheum Dis 2004;63:269–73.
      OpenUrlAbstract/FREE Full Text
    39. ↵
      1. Nebelung W,
      2. Wuschech H
      . Thirty-five years of follow-up of anterior cruciate ligament-deficient knees in high-level athletes. Arthroscopy 2005;21:696–702.
      OpenUrlCrossRefPubMedWeb of Science
    40. ↵
      1. Ait Si Selmi T,
      2. Fithian D,
      3. Neyret P
      . The evolution of osteoarthritis in 103 patients with ACL reconstruction at 17 years follow-up. Knee 2006;13:353–8.
      OpenUrlCrossRefPubMedWeb of Science
    41. ↵
      1. Oiestad BE,
      2. Holm I,
      3. Aune AK,
      4. et al
      . Knee function and prevalence of knee osteoarthritis after anterior cruciate ligament reconstruction: a prospective study with 10 to 15 years of follow-up. Am J Sports Med 2010;38:2201–10.
      OpenUrlAbstract/FREE Full Text
    42. ↵
      1. Gillquist J,
      2. Messner K
      . Anterior cruciate ligament reconstruction and the long-term incidence of gonarthrosis. Sports Med 1999;27:143–56.
      OpenUrlCrossRefPubMedWeb of Science
    43. ↵
      1. Øiestad BE,
      2. Engebretsen L,
      3. Storheim K,
      4. et al
      . Knee osteoarthritis after anterior cruciate ligament injury: a systematic review. Am J Sports Med 2009;37:1434–43.
      OpenUrlAbstract/FREE Full Text
    44. ↵
      1. Spector TD,
      2. Harris PA,
      3. Hart DJ,
      4. et al
      . Risk of osteoarthritis associated with long-term weight-bearing sports: a radiologic survey of the hips and knees in female ex-athletes and population controls. Arthritis Rheum 1996;39:988–95.
      OpenUrlCrossRefPubMedWeb of Science
    45. ↵
      1. Sandmark H,
      2. Vingård E
      . Sports and risk for severe osteoarthrosis of the knee. Scand J Med Sci Sports 1999;9:279–84.
      OpenUrlPubMedWeb of Science
    46. ↵
      1. Roddy E,
      2. Zhang W,
      3. Doherty M,
      4. et al
      . Evidence-based recommendations for the role of exercise in the management of osteoarthritis of the hip or knee – the MOVE consensus. Rheumatology (Oxford) 2005;44:67–73.
      OpenUrlAbstract/FREE Full Text
    47. ↵
      1. Deacon A,
      2. Bennell K,
      3. Kiss ZS,
      4. et al
      . Osteoarthritis of the knee in retired, elite Australian Rules footballers. Med J Aust 1997;166:187–90.
      OpenUrlPubMedWeb of Science
    48. ↵
      1. Buckwalter JA,
      2. Lane NE
      . Athletics and osteoarthritis. Am J Sports Med 1997;25:873–81.
      OpenUrlAbstract/FREE Full Text
    49. ↵
      1. Buckwalter JA,
      2. Lane NE
      . Does participation in sports cause osteoarthritis? Iowa Orthop J 1997;17:80–9.
      OpenUrlPubMed
    50. ↵
      1. Arøen A,
      2. Løken S,
      3. Heir S,
      4. et al
      . Articular cartilage lesions in 993 consecutive knee arthroscopies. Am J Sports Med 2004;32:211–15.
      OpenUrlAbstract/FREE Full Text
    51. ↵
      1. Brittberg M,
      2. Lindahl A,
      3. Nilsson A,
      4. et al
      . Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation. N Engl J Med 1994;331:889–95.
      OpenUrlCrossRefPubMedWeb of Science
    52. ↵
      1. Krishnan SP,
      2. Skinner JA,
      3. Carrington RW,
      4. et al
      . Collagen-covered autologous chondrocyte implantation for osteochondritis dissecans of the knee: two to seven-year results. J Bone Joint Surg Br 2006;88:203–5.
      OpenUrlCrossRefPubMed
    53. ↵
      1. Bartlett W,
      2. Skinner JA,
      3. Gooding CR,
      4. et al
      . Autologous chondrocyte implantation versus matrix-induced autologous chondrocyte implantation for osteochondral defects of the knee: a prospective, randomised study. J Bone Joint Surg Br 2005;87:640–5.
      OpenUrlCrossRefPubMed
    54. ↵
      1. Nehrer S,
      2. Domayer S,
      3. Dorotka R,
      4. et al
      . Three-year clinical outcome after chondrocyte transplantation using a hyaluronan matrix for cartilage repair. Eur J Radiol 2006;57:3–8.
      OpenUrlCrossRefPubMedWeb of Science
    55. ↵
      1. Behrens P,
      2. Bitter T,
      3. Kurz B,
      4. et al
      . Matrix-associated autologous chondrocyte transplantation/implantation (MACT/MACI)–5-year follow-up. Knee 2006;13:194–202.
      OpenUrlCrossRefPubMedWeb of Science
    56. ↵
      1. Steinwachs M,
      2. Kreuz PC
      . Autologous chondrocyte implantation in chondral defects of the knee with a type I/III collagen membrane: a prospective study with a 3-year follow-up. Arthroscopy 2007;23:381–7.
      OpenUrlCrossRefPubMedWeb of Science
    57. ↵
      1. van den Berg WB,
      2. van der Kraan PM,
      3. Scharstuhl A,
      4. et al
      . Growth factors and cartilage repair. Clin Orthop Relat Res 2001;(391 Suppl):S244–50.
    58. ↵
      1. Engebretsen L,
      2. Arendt E,
      3. Fritts HM
      . Osteochondral lesions and cruciate ligament injuries. MRI in 18 knees. Acta Orthop Scand 1993;64:434–6.
      OpenUrlPubMedWeb of Science
      1. Wei X,
      2. Messner K
      . Maturation-dependent durability of spontaneous cartilage repair in rabbit knee joint. J Biomed Mater Res 1999;46:539–48.
      OpenUrlCrossRefPubMedWeb of Science
    60. ↵
      1. Twyman RS,
      2. Desai K,
      3. Aichroth PM
      . Osteochondritis dissecans of the knee. A long-term study. J Bone Joint Surg Br 1991;73:461–4.
      OpenUrlPubMedWeb of Science
    61. ↵
      1. Sharma L,
      2. Hurwitz DE,
      3. Thonar EJ,
      4. et al
      . Knee adduction moment, serum hyaluronan level, and disease severity in medial tibiofemoral osteoarthritis. Arthritis Rheum 1998;41:1233–40.
      OpenUrlCrossRefPubMedWeb of Science
    62. ↵
      1. Honkonen SE
      . Degenerative arthritis after tibial plateau fractures. J Orthop Trauma 1995;9:273–7.
      OpenUrlCrossRefPubMedWeb of Science
    63. ↵
      1. Buckwalter JA,
      2. Mankin HJ
      . Articular cartilage: degeneration and osteoarthritis, repair, regeneration, and transplantation. Instr Course Lect 1998;47:487–504.
      OpenUrlPubMed
    64. ↵
      1. Knutsen G,
      2. Engebretsen L,
      3. Ludvigsen TC,
      4. et al
      . Autologous chondrocyte implantation compared with microfracture in the knee. A randomized trial. J Bone Joint Surg Am 2004;86-A:455–64.
      OpenUrlPubMed
    65. ↵
      1. Gudas R,
      2. Stankevicius E,
      3. Monastyreckiene E,
      4. et al
      . Osteochondral autologous transplantation versus microfracture for the treatment of articular cartilage defects in the knee joint in athletes. Knee Surg Sports Traumatol Arthrosc 2006;14:834–42.
      OpenUrlCrossRefPubMedWeb of Science
    66. ↵
      1. Knutsen G,
      2. Drogset JO,
      3. Engebretsen L,
      4. et al
      . A randomized trial comparing autologous chondrocyte implantation with microfracture. Findings at five years. J Bone Joint Surg Am 2007;89:2105–12.
      OpenUrlCrossRefPubMed
    67. ↵
      1. Steadman JR,
      2. Briggs KK,
      3. Rodrigo JJ,
      4. et al
      . Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up. Arthroscopy 2003;19:477–84.
      OpenUrlCrossRefPubMedWeb of Science
    68. ↵
      1. Namdari S,
      2. Baldwin K,
      3. Anakwenze O,
      4. et al
      . Results and performance after microfracture in National Basketball Association athletes. Am J Sports Med 2009;37:943–8.
      OpenUrlAbstract/FREE Full Text
    69. ↵
      1. Riyami M,
      2. Rolf C
      . Evaluation of microfracture of traumatic chondral injuries to the knee in professional football and rugby players. J Orthop Surg Res 2009;4:13.
      OpenUrlCrossRefPubMed
    70. ↵
      1. Gobbi A,
      2. Nunag P,
      3. Malinowski K
      . Treatment of full thickness chondral lesions of the knee with microfracture in a group of athletes. Knee Surg Sports Traumatol Arthrosc 2005;13:213–21.
      OpenUrlCrossRefPubMedWeb of Science
    71. ↵
      1. Peterson L,
      2. Minas T,
      3. Brittberg M,
      4. et al
      . Two- to 9-year outcome after autologous chondrocyte transplantation of the knee. Clin Orthop Relat Res 2000;374:212–34.
      OpenUrlCrossRefPubMed
    72. ↵
      1. Minas T
      . Autologous chondrocyte implantation for focal chondral defects of the knee. Clin Orthop Relat Res 2001;(391 Suppl):S349–61.
    73. ↵
      1. Peterson L,
      2. Brittberg M,
      3. Kiviranta I,
      4. et al
      . Autologous chondrocyte transplantation. Biomechanics and long-term durability. Am J Sports Med 2002;30:2–12.
      OpenUrlAbstract/FREE Full Text
    74. ↵
      1. Bentley G,
      2. Biant LC,
      3. Carrington RW,
      4. et al
      . A prospective, randomised comparison of autologous chondrocyte implantation versus mosaicplasty for osteochondral defects in the knee. J Bone Joint Surg Br 2003;85:223–30.
      OpenUrlCrossRefPubMed
    75. ↵
      1. Horas U,
      2. Pelinkovic D,
      3. Herr G,
      4. et al
      . Autologous chondrocyte implantation and osteochondral cylinder transplantation in cartilage repair of the knee joint. A prospective, comparative trial. J Bone Joint Surg Am 2003;85-A:185–92.
      OpenUrlPubMed
    76. ↵
      1. Dozin B,
      2. Malpeli M,
      3. Cancedda R,
      4. et al
      . Comparative evaluation of autologous chondrocyte implantation and mosaicplasty: a multicentered randomized clinical trial. Clin J Sport Med 2005;15:220–6.
      OpenUrlCrossRefPubMed
      1. Muellner T,
      2. Knopp A,
      3. Ludvigsen TC,
      4. et al
      . Failed autologous chondrocyte implantation. Complete atraumatic graft delamination after two years. Am J Sports Med 2001;29:516–19.
      OpenUrlFREE Full Text
      1. Saris DB,
      2. Vanlauwe J,
      3. Victor J,
      4. et al
      . Treatment of symptomatic cartilage defects of the knee: characterized chondrocyte implantation results in better clinical outcome at 36 months in a randomized trial compared to microfracture. Am J Sports Med 2009;37 (Suppl 1):10–19S.
      OpenUrlCrossRef
    79. ↵
      1. Kreuz PC,
      2. Steinwachs M,
      3. Erggelet C,
      4. et al
      . Importance of sports in cartilage regeneration after autologous chondrocyte implantation: a prospective study with a 3-year follow-up. Am J Sports Med 2007;35:1261–8.
      OpenUrlAbstract/FREE Full Text
    80. ↵
      1. Kreuz PC,
      2. Steinwachs MR,
      3. Erggelet C,
      4. et al
      . Results after microfracture of full-thickness chondral defects in different compartments in the knee. Osteoarthr Cartil 2006;14:1119–25.
      OpenUrlCrossRefPubMedWeb of Science
    81. ↵
      1. Iwasa J,
      2. Engebretsen L,
      3. Shima Y,
      4. et al
      . Clinical application of scaffolds for cartilage tissue engineering. Knee Surg Sports Traumatol Arthrosc 2009;17:561–77.
      OpenUrlCrossRefPubMedWeb of Science
    82. ↵
      1. Bobic V
      . Arthroscopic osteochondral autograft transplantation in anterior cruciate ligament reconstruction: a preliminary clinical study. Knee Surg Sports Traumatol Arthrosc 1996;3:262–4.
      OpenUrlCrossRefPubMed
    83. ↵
      1. Hangody L,
      2. Feczkó P,
      3. Bartha L,
      4. et al
      . Mosaicplasty for the treatment of articular defects of the knee and ankle. Clin Orthop Relat Res 2001;(391 Suppl):S328–36.
    84. ↵
      1. Safran MR,
      2. Kim H,
      3. Zaffagnini S
      . The use of scaffolds in the management of articular cartilage injury. J Am Acad Orthop Surg 2008;16:306–11.
      OpenUrlAbstract/FREE Full Text
    85. ↵
      1. Williams RJ,
      2. Gamradt SC
      . Articular cartilage repair using a resorbable matrix scaffold. Instr Course Lect 2008;57:563–71.
      OpenUrlPubMed
    86. ↵
      1. Kerker JT,
      2. Leo AJ,
      3. Sgaglione NA
      . Cartilage repair: synthetics and scaffolds: basic science, surgical techniques, and clinical outcomes. Sports Med Arthrosc 2008;16:208–16.
      OpenUrlCrossRefPubMedWeb of Science
    87. ↵
      1. Koga H,
      2. Engebretsen L,
      3. Brinchmann JE,
      4. et al
      . Mesenchymal stem cell-based therapy for cartilage repair: a review. Knee Surg Sports Traumatol Arthrosc 2009;17:1289–97.
      OpenUrlCrossRefPubMedWeb of Science
    88. ↵
      1. Moseley B
      . Arthroscopic surgery did not provide additional benefit to physical and medical therapy for osteoarthritis of the knee. J Bone Joint Surg Am 2009;91:1281.
      OpenUrlCrossRefPubMed
    89. ↵
      1. Lobenhoffer P,
      2. Agneskirchner JD
      . Improvements in surgical technique of valgus high tibial osteotomy. Knee Surg Sports Traumatol Arthrosc 2003;11:132–8.
      OpenUrlPubMedWeb of Science
    90. ↵
      1. Odenbring S,
      2. Tjörnstrand B,
      3. Egund N,
      4. et al
      . Function after tibial osteotomy for medial gonarthrosis below aged 50 years. Acta Orthop Scand 1989;60:527–31.
      OpenUrlPubMedWeb of Science
    91. ↵
      1. Salzmann GM,
      2. Ahrens P,
      3. Naal FD,
      4. et al
      . Sporting activity after high tibial osteotomy for the treatment of medial compartment knee osteoarthritis. Am J Sports Med 2009;37:312–18.
      OpenUrlAbstract/FREE Full Text
    92. ↵
      1. Bradbury N,
      2. Borton D,
      3. Spoo G,
      4. et al
      . Participation in sports after total knee replacement. Am J Sports Med 1998;26:530–5.
      OpenUrlAbstract/FREE Full Text
    93. ↵
      1. Fisher N,
      2. Agarwal M,
      3. Reuben SF,
      4. et al
      . Sporting and physical activity following Oxford medial unicompartmental knee arthroplasty. Knee 2006;13:296–300.
      OpenUrlCrossRefPubMedWeb of Science
    94. ↵
      1. Naal FD,
      2. Fischer M,
      3. Preuss A,
      4. et al
      . Return to sports and recreational activity after unicompartmental knee arthroplasty. Am J Sports Med 2007;35:1688–95.
      OpenUrlAbstract/FREE Full Text
    95. ↵
      1. Hopper GP,
      2. Leach WJ
      . Participation in sporting activities following knee replacement: total versus unicompartmental. Knee Surg Sports Traumatol Arthrosc 2008;16:973–9.
      OpenUrlCrossRefPubMedWeb of Science
    96. ↵
      1. Walton NP,
      2. Jahromi I,
      3. Lewis PL,
      4. et al
      . Patient-perceived outcomes and return to sport and work: TKA versus mini-incision unicompartmental knee arthroplasty. J Knee Surg 2006;19:112–16.
      OpenUrlPubMed
    97. ↵
      1. Hascall VC,
      2. Kuettner KE
      1. Hochberg M
      . Prevention of lower limb osteoarthritis: data from the Johns Hopkins Precursors Study. In:Hascall VC, Kuettner KEeds. The many faces of osteoarthritis. Basel: Birkhauser, 2002:31–7.
    98. ↵
      1. Felson DT
      . Preventing knee and hip osteoarthritis. Bull Rheum Dis 1998;47:1–4.
      OpenUrlPubMedWeb of Science
    99. ↵
      1. Felson DT,
      2. Hannan MT,
      3. Naimark A,
      4. et al
      . Occupational physical demands, knee bending, and knee osteoarthritis: results from the Framingham Study. J Rheumatol 1991;18:1587–92.
      OpenUrlPubMedWeb of Science
    100. ↵
      1. Felson DT,
      2. Zhang Y,
      3. Anthony JM,
      4. et al
      . Weight loss reduces the risk for symptomatic knee osteoarthritis in women. The Framingham Study. Ann Intern Med 1992;116:535–9.
      OpenUrlCrossRefPubMedWeb of Science
    101. ↵
      1. Manninen P,
      2. Riihimäki H,
      3. Heliövaara M,
      4. et al
      . Overweight, gender and knee osteoarthritis. Int J Obes Relat Metab Disord 1996;20:595–7.
      OpenUrlPubMedWeb of Science
    102. ↵
      1. Zhang W,
      2. Moskowitz RW,
      3. Nuki G,
      4. et al
      . OARSI recommendations for the management of hip and knee osteoarthritis, Part II: OARSI evidence-based, expert consensus guidelines. Osteoarthr Cartil 2008;16:137–62.
      OpenUrlCrossRefPubMedWeb of Science
    103. ↵
      1. Olsen OE,
      2. Myklebust G,
      3. Engebretsen L,
      4. et al
      . Exercises to prevent lower limb injuries in youth sports: cluster randomised controlled trial. BMJ 2005;330:449.
      OpenUrlAbstract/FREE Full Text
    104. ↵
      1. Myklebust G,
      2. Engebretsen L,
      3. Braekken IH,
      4. et al
      . Prevention of anterior cruciate ligament injuries in female team handball players: a prospective intervention study over three seasons. Clin J Sport Med 2003;13:71–8.
      OpenUrlCrossRefPubMedWeb of Science
    105. ↵
      1. Soligard T,
      2. Myklebust G,
      3. Steffen K,
      4. et al
      . Comprehensive warm-up programme to prevent injuries in young female footballers: cluster randomised controlled trial. BMJ 2008;337:a2469.
      OpenUrlAbstract/FREE Full Text

    Footnotes

    • Competing interests None.

    • Provenance and peer review Not commissioned; externally peer reviewed