Scand J Med Sci Sports 2015: 25 (Suppl. 2): 10–15 doi: 10.1111/sms.12465
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Alpine Skiing With total knee ArthroPlasty (ASWAP): clinical and radiographic outcomes T. Hofstaedter1, C. Fink2, U. Dorn1, B. Pötzelsberger3, C. Hepperger2, K. Gordon1, E. Müller3 University Clinic of Orthopaedics, PMU Salzburg, Salzburg, Austria, 2Sportsclinic Austria, Innsbruck, Austria, 3Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria Corresponding author: Thomas Hofstaedter, MBA, Department of Orthopaedic Surgery, PMU Salzburg, Landeskrankenhaus Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria. Tel: +43 662 4482 57322, E-mail: [email protected]
1
Accepted for publication 4 March 2015
The aim of the study was to assess the effect of a recreational alpine skiing intervention on implant-related factors, such as loosening and wear, in patients with total knee arthoplasty (TKA). A group of 16 TKA patients were examined 2.3 ± 0.1 years after skiing about 80 days over three seasons inclusive of a ski intervention of 2–3 times per week (25.5 days) over a 12-week period. Mean follow-up period was 5.1 ± 1 years after surgery. All patients had excellent clinical and radiological outcomes. The average flexion was 120–130°, the average Oxford
Knee Score increased from 15 points pre-operatively to 47.4 points post-operatively. An average Tegner activity level of 5.5 was assessed, indicating a very high postoperative activity level. No radiolucencies or osteolyses were observed in any of the radiographs. One patient sustained a meniscal tear in the contralateral knee. Recreational alpine skiing on intermediate terrain at moderate speed can be recommended after TKA. Analysis of mid-term follow-up has not shown any negative effect on the implant loosening or additional polyethylene wear.
The primary objective of total knee arthroplasty (TKA) is to decrease pain, restore a functional knee joint, and improve patients’ quality of life. However, patients’ and surgeons’ expectations today are higher than those of years ago; this includes long-term implant survivors and participation in sports activities, including some highimpact sports. The demand for total joint arthroplasty is rising, being particularly high in Western Europe and Northern America. In particular, the demand in patients younger than 65 years will increase (Kurtz et al., 2009; Mody & Mody, 2014). In the United States, the total number of procedures increased by 6.0% for primary total hip arthroplasty (THA) and 6.1% for primary TKA from 2009 to 2010 (Kurtz et al., 2014). In Austria, total knee replacements (TKR) increased by 11% from 2009 to 2013 (Statistik Austria, 2009–2013), although this is one of the countries with the highest rates of knee and hip replacements in Europe (249/100 000 people had hip replacements in 2010 and 201/100 000 people had knee replacements in 2010; OECD, 2012). The reason is not only an increased life expectancy and population growth but also an increasing number of younger patients who undergo the operation. Osteoarthritis is mainly associated with age, but it is also associated with genetic factors, obesity, lifestyle, and sports activity (Richmond et al., 2013). The populations’ increasing
activity levels leads to a decreased inhibition threshold of undergoing joint arthroplasty. This leads to an increasing number of TKA patients between 40 and 60 years of age. Younger patients are usually more physically active; therefore, expectations following TKA are generally higher than the expectations of older patients. Nevertheless, there is also a growing number of senior citizens hoping to live a more active lifestyle after undergoing total joint replacement (TJR; Trousdale et al., 1999). Although the primary goals for the younger age group are similar regarding pain relief and restoration of function, younger patients additionally expect a quick recovery, return to activities of daily living, and no limitations of their desired sport activities. However, based on our own experience, expectations of patients undergoing TJR are generally changing, regardless of the patient’s age, sex, or culture. In all age groups, patients tend to be more active. Sport has become an essential part of life, not only because of an increased quality of life and health but also because it is an important factor for maintaining social relationships. Therefore, we must accept the patient’s desire to not quit sports after undergoing TJR. Wylde et al. (2008), for example, reported a rate of approximately 35% of patients participating in sports before undergoing surgery, with 61.4% of those patients returning to their sporting activity after surgery.
10
Outcome after skiing with total knee arthroplasty However, some questions need to be answered: Are sporting activities, particularly high-impact sports, recommendable after hip or knee replacement? Does high activity lead to early loosening of the prostheses or to premature polyethylene wear? Only a few studies have identified the influence of high-impact sports on TKA (Mont et al., 2002a, b, 2008; Seyler et al., 2006; Keren et al., 2013; Mayr et al., 2015) and some physicians continue to have concerns about sports activity after TKA. Recommendations from orthopedic societies either do not exist or are limited; these recommendations are normally based on surgeons’ surveys and not on hard evidence. Despite the lack of data and evidence, there is a trend for surgeons to allow more sports activities after TJR. From 1999 to 2005, the number of sport activities “not recommended” by the American Knee Society members decreased from 12 to 5; the numbers of “allowed” activities increased from 18 to 19 (Healy et al., 2008). This trend seems to continue when asking colleagues about their recommendations for their patients’ sports habits. Reasons might be new developments such as new bearing surfaces (e.g., highly crosslinked polyethylene), implant coats, or new implant designs. Increased polyethylene wear has always been considered to be associated with high activity (Schmalzried et al., 1998; Gschwend et al., 2000; Lavernia et al., 2001; Hamai et al., 2008; Ollivier et al., 2012). However, there are also contradicting studies, which have documented no negative influence of sports activities on polyethylene wear (Mont et al., 2002a, b; Abe et al., 2014). With more frequent use of highly cross-linked polyethylene, loosening caused by polyethylene wear should be significantly reduced (Popoola et al., 2010). Surgeons are not only concerned about the risk of early prosthetic loosening associated with high-impact sports, but also about the increased risk of injury. Although it is a very rare complication, suffering a periprosthetic fracture while participating in sports activities is possible (McGrory, 2004). A periprosthetic fracture is a major complication and is associated with high morbidity and mortality (Bhattacharyya et al., 2007). These fractures are difficult to treat and require complex surgeries and therapeutic strategies. Because there is a lack of objective data regarding the effects of sports participation on the outcomes of arthroplasty, the goal of this study was to evaluate the risk of alpine skiing in patients with TKA. Material and methods Indications for total knee replacement include degenerative osteoarthritis in all patients. The details regarding the study design and participants are presented elsewhere by Kösters et al. (2015). Patients were selected from the patient’s knee arthroplasty lists of the Orthopaedic University Clinic, Salzburg and the Sportsclinic, Austria. Individuals were required to meet the following criteria: 1 to 5 years post-operative; age 60–80; intermedi-
ate level skier; no previous arthroplasties performed (e.g., hip or shoulder arthroplasty); no pain or functional limitation of the operated knee; no radiographic findings of aseptic loosening; no other severe osteoarthritis, pain, or functional limitation of the musculo-skeletal system which may have negatively affected intensity of skiing. For our study question, we also included patients with bilateral TKA. A total of 16 patients (11 from the Salzburg group, 5 from the Innsbruck group) demonstrating willingness to regularly ski (2–3 days/week, 3–4 h/day) for 12 weeks (an average of 25.5 days all together) were included in the intervention group (IG). They completed an average of 3393 vertical meters of downhill skiing, with a total skiing distance of 33.6 km/day (Kösters et al., 2015). Another 11 patients fulfilled the inclusion criteria but were not willing to ski regularly; as such, these patients were assigned to the control group (CG; Kösters et al., 2015). In this paper, we will not expand on the CG because of the irrelevance of this group regarding the orthopedic questions addressed in this paper. Fifteen patients (5 females, 11 males) were treated with a knee prosthesis from Zimmer Inc. (Warsaw, IN, USA) [NexGen Cruciate retaining (CR) knee in 10 patients and Nex Gen Ligamentum posterior stabilized (LPS) knee (both prostheses are mobile fixed components) in five patients], whereas one patient received a LCS knee from Depuy Inc. (Warsaw, IN, USA) (mobile bearing component). One patient received bilateral knee arthroplasties (Nex Gen CR knee of Zimmer Lto), and two patients received additional replacements of the patella. All TKAs were performed over a standard medial parapatellar approach. The average age at time of the skiing intervention was 69.8 ± 4.4 years. The average period of intervention was 2.7 ± 1 years post-operative. The average follow-up period was 5.1 ± 1 years post-operative. The follow-up after skiing intervention was 2.3 ± 0.1 years. During the follow-up time, most patients had already gone skiing an additional two winter seasons, with several skiing days (average 20 skiing days/year); all together, the last follow-up was after approximately 80 skiing days. The intervention program consisted of 2–3 days skiing per week over a period of 12 weeks (Kösters et al., 2015). The study participants were divided into three groups according to the region (Innsbruck and Salzburg); in addition, the Salzburg group was also assigned to one of two homogeneous groups, based on their skiing skills. The groups skied each day using a “Guided Skiing” format, with each group lead by one ski instructor. At the time of follow-up, patients were examined clinically and had radiographs taken (anterior/posterior, lateral view, and patella tangential view). At the same time, knee and functional scores were calculated using the Oxford Knee Score, the Knee Society Score, and the Tegner activity level (Tegner & Lysholm, 1985; Insall et al., 1989; Dawson et al., 1998).
Results Every patient included in the study was willing to present at follow-up [5.1 ± 1 (mean ± SD) and 2.3 ± 0.1 years post-operatively and post-intervention, respectively]. All patients were evaluated clinically and radiologically at the two involved orthopedic clinics in Salzburg and Innsbruck. Knee function The clinical examination at follow-up revealed very good to excellent knee function in all patients. The average flexion was between 120° and 130°, and no patient had a limited flexion less than 115°. The average
11
Hofstaedter et al. Oxford Knee Score was 47.4, which was compared with the pre-operative score of 15. The average Tegner activity level was 5.5, which is indicative of a very high post-operative activity level. The Knee Society Score at the time of follow-up was 97.2 (Knee Society Score data collected only in the Salzburg group, which included 11 skiers, and was not evaluated pre-intervention).
Radiological assessment All patients consented to a radiological examination, pre- and post-interventional, at follow-up. No patient showed a reduction in the height of the polyethylene inlay in the postero-anterior view. No radiolucent lines were found between the prosthesis and bone. No osteolyses were detectable (Fig. 1).
Complications One patient who was originally included in the IG had to be excluded from the study because this patient sustained a periprosthetic femur fracture while skiing independently of the study; this was prior to the start of the study. He was successfully operated on with a plate and continued his ski activity the following winter. One patient had to interrupt skiing for a number of days because of a torn meniscus in the contralateral knee, which was treated conservatively. Another patient had to stop skiing after 8 days because of cardiovascular problems. This patient also moved on to regular skiing the following winter. No significant injury was observed during the intervention. Discussion Performing sports after TJR has grown more and more important during the last few years (Healy et al., 2008). Several reports are concerned with the outcomes of TJR in patients participating in sports. Just a few studies concentrate on high-impact sports in patients with TKA or THA (Bradbury et al., 1998; Bock et al., 2003; Niederle & Knahr, 2007) and even less focus on alpine skiing (Gschwend et al., 2000; Müller et al., 2011; Woon & Amstutz, 2012). To our knowledge, this is the first study to determine the effect of alpine skiing on TKA in a larger patient population, also analyzing further parameters during pre-, post-, and retention-test sessions (see: Kösters et al., 2015). After an average 25.5 days of skiing and despite the fact that all patients additionally went skiing prior to and after the intervention on a private basis, all patients showed an excellent clinical and radiographic outcome, with an average flexion between 120° and 130°, an average Oxford Knee Score of 47.4, an average Tegner activity level of 5.5, and a Knee Society Score of 97.2.
12
Fig. 1. Knee radiographs of a 68-year-old male with severe osteoarthritis of the left knee, treated with TKA (Zimmer Nex Gen LPS). This patient additionally received a patella replacement. Left knee anterior/posterior (a) and lateral view (b) preoperatively; 5/2010. Severe osteoarthritis with joint space narrowing and meniscal calcifications as well as retropatellar arthritis. Left knee anterior/posterior (c) and lateral view (d) at FU 12/2011 (1.5 years post-operatively, before skiing intervention). No radiolucencies detectable. Left knee anterior/posterior (e) and lateral view (f) at FU 7/2014 (4.1 years post-operatively, 2.4 years after skiing intervention). No radiolucencies detectable. No change in polyethylene height compared with preintervention X-ray (c, d).
Outcome after skiing with total knee arthroplasty The Oxford Knee Score is a patient-reported outcome score, which was specifically developed to assess the necessity of undergoing TKR and to measure the outcome after TKR. Anyone with an Oxford Knee Score below 20 may be referred for TKR and a score over 40 may indicate satisfactory joint function. An average Oxford Knee Score of 47.4 is indicative of an excellent outcome after TKA. The Knee Society Score was developed as a simple, objective scoring system to rate the knee and patient’s functional abilities such as walking and stair climbing before and after TKA (Scuderi et al., 2012). It is the most popular score to evaluate outcomes after TKA. A score over 80 points is indicative of an excellent outcome after TKA. The Tegner activity level scale is a valid measure of return to activity after injuries or operations. The score varies from 0 to 10. An average of 5.5 points is indicative for a high activity level after TKA like work-heavy labor, competitive sport cycling, or tennis. Not showing any signs of early prosthetic loosening or increased polyethylene wear at midterm follow-up, and resulting in e.g., improved gait performance with a reduction in gait asymmetry (see Pötzelsberger et al., 2015), we conclude that recreational alpine skiing can be safely performed in pre-operatively sportive patients. In a recently published systematic review, Jassim et al. (2014) concluded that especially young, pre-operatively active patients were able to return to sports activities after TJR, although intensity of activities tended to be less post-operatively. Active patients scored higher Knee Society Scores than sedentary ones (85.2 vs 83.4 points, respectively) after an average of 74 months postoperatively, and rates of implant failures were not increased (Bock et al., 2003; Jassim et al., 2014). When comparing sports activity levels, patients who required revision surgery were less active than patients without failed knee prosthesis (Jones et al., 2004). Mont et al. (2007) reported similar results in high and low activity patients with TKA after a mean follow-up period of 7 years, without any signs of progressive radiolucencies or osteolysis in either group. Patients with THA participating in alpine or crosscountry skiing did not show increased numbers of aseptic loosening, but an increased average wear rate after 10 years in highly physically active patients – Gschwend et al. (2000); therefore, they recommended controlled alpine or cross-country skiing. We did not find any surveys concerned with wear rates in TKA associated with high-impact sports. In general, knee functional scores improve after TKR. Long et al. (2014) report a mean Tegner score improving from 1.5 points to 3.0 post-operatively, with an average Knee Society Score of 87.4 points post-operatively. Post-operative improvement in Knee Society Score reached a mean of 48 points after undergoing TKA (Marker et al., 2009; Long et al., 2014).
However, sports activity decreases after undergoing TKR surgery (Bradbury et al., 1998; Chatterji et al., 2005; Dahm et al., 2008). Nevertheless, some of those patients who want to return to high-impact sports after TKA – based on the present results and those of past studies – can enjoy excellent clinical outcomes for at least 2.3 ± 0.1 years afterwards. Mont et al. (2008) gave similar recommendations for a follow-up period of 4 years in patients with TKA performing different kinds of high-impact sports on average four times per week – among those were three cross-country skiers. Of those 33 patients, 32 had a Knee Society Score greater than 80 points, with a mean range of motion of 119° (range, 105–130) at final follow-up. Concerned with implant loosening, Mayr et al. (2015) examined a total of 81 patients performing sports activity after TKA, with 25% of them performing high-impact sports. Even at a mean follow-up of 6.4 years, no individual showed evident signs of wear or component loosening. Limiting is the fact that for the study’s orthopedic approach, we did not compare radiographic results with those of matched patients not practicing alpine skiing or other high-impact activities. Knee Society Scores were not evaluated post-intervention in all patients and were not evaluated pre-intervention; therefore, a comparison of the scores before and after the average 80 days of skiing was not possible – we can hereby not objectify whether patients’ scores improved after alpine skiing or not, despite good clinical and radiographic outcomes. Also, we did not follow our patients long enough to give clear recommendations concerning high-demand activities after TKR and their long-term influences on implant survival. A long-term follow-up study would be necessary to clarify such effects. In most studies, the intensity level of sports activities was not evaluated. In our survey, patients skied with a skiing instructor every day. Skiing intensity throughout the groups was therefore uniform. It should be strongly kept in mind, that besides having a possible influence on implant loosening, high-impact sports may increase the risk of injuries associated with TJR. Periprosthetic fractures are among the major and most dreaded complications after TJR with an incidence of 0.58% to 2.5% after TKA (Rorabeck & Taylor, 1999; Singh & Bhalodiya, 2013). The main risk factors for periprosthetic fractures are rheumatoid polyarthritis, severe osteoporosis, implant loosening, revision surgery, and significant anatomical deformities (Della Rocca et al., 2011; Savin et al., 2012; Whitehouse & Mehendale, 2014). Savin et al. (2012) report that most of the fractures are the result of minor trauma caused by a same-level fall. However, very physically active patients are especially at risk of suffering a periprosthetic fracture while doing sports (Savin et al., 2012; Whitehouse & Mehendale, 2014).
13
Hofstaedter et al. There was one patient who should have been included in the IG in the present study but who suffered a periprosthetic supracondylar femur fracture before the intervention started. Technically, it occurred while skiing, but he was actually standing still on the skis when he was hit by a skier from above. Periprosthetic fractures are major complications and mostly require a challenging operative treatment with high post-operative complication rates including, e.g., infections, non-union and early loosening, resulting in the need for further revision surgery (Herrera et al., 2008; Leino et al., 2014). According to the radiographic and clinical outcomes in all 16 patients during a post-interventional follow-up period of 2.3 ± 0.1 years, guided alpine skiing with TKA is not associated with increased rates of implant loosening, wear, or osteolysis. Skiing with TKA can be recommended in pre-operatively physically active patients who show good functional postoperative outcomes without any signs of loosening on radiographic evaluation. We classified a good functional outcome as a painless knee prosthesis without severe flexion contractures, limited range of motion, or severe ligamentous instability. By all means, it is most important to inform patients about the risk of severe injuries associated with an artificial joint, such as periprosthetic fractures, which are particularly difficult to treat.
Patients should be sensitized to the higher risk of loosening and wear associated with sports activities of high intensity and the necessity for revision surgery with implant loosening or periprosthetic fractures. Recommendations must be individualized and have to meet the increasing demand of patients to return to sports after surgery. However, questions remain: are orthopedic surgeons able to fulfill these demands and can prosthetic designs fulfill these demands without the risk of early aseptic loosening?
Perspectives The demand for TKA worldwide will further increase over the next decades. The challenge for surgeons and prosthetic manufacturers will be to fulfill the patients’ demands of continuing high-impact sports after TKA. With more frequent use of highly cross-linked polyethylene, loosening caused by polyethylene wear should be significantly reduced. Additionally, new prosthetic designs have been introduced to the market in the last few years. Key words: Alpine radiolucency.
skiing,
knee
replacement,
References Abe H, Sakai T, Nishii T, Takao M, Nakamura N, Sugano N. Jogging after total hip arthroplasty. Am J Sports Med 2014: 42 (1): 131–137. Bhattacharyya T, Chang D, Meigs JB, Estok DM, Malchau H. Mortality after periprosthetic fracture of the femur. J Bone Joint Surg Am 2007: 89: 2658–2662. Bock P, Schatz K, Wurnig C. Physical activity after total knee replacement. Z Orthop Ihre Grenzgeb 2003: 141 (3): 272–276. Bradbury N, Borton D, Spoo G, Cross MJ. Participation in sports after total knee replacement. Am J Sports Med 1998: 26: 530–535. Chatterji U, Ashworth MJ, Lewis PL, Dobson PJ. Effect of total knee arthroplasty on recreational and sporting activity. ANZ J Surg 2005: 75: 405–408. Dahm DL, Barnes SA, Harrington JR, Sayeed SA, Berry DJ. Patient-reported activity level after total knee arthroplasty. J Arthroplasty 2008: 23: 401–407. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br 1998: 80: 63–69.
14
Della Rocca GJ, Leung KS, Pape HC. Periprosthetic fractures: epidemiology and future projections. J Orthop Trauma 2011: 25 (Suppl. 2): S66–S70. Gschwend N, Frei T, Morscher E, Nigg B, Loehr J. Alpine and cross-country skiing after total hip replacement 2 cohorts of 50 patients each, one active, the other inactive in skiing, followed for 5–10 years. Acta Orthop Scand 2000: 71: 243–249. Hamai S, Miura H, Higaki H, Shimoto T, Matsuda S, Okazaki K, Iwamoto Y. Three-dimensional knee joint kinematics during golf swing and stationary cycling after total knee arthroplasty. J Orthop Res 2008: 26: 1556–1561. Healy WL, Sharma S, Schwartz B, Iorio R. Athletic activity after total joint arthroplasty. J Bone Joint Surg Am 2008: 90: 2245–5. Herrera DA, Kregor PJ, Cole PA, Levy BA, Jönsson A, Zlowodzki M. Treatment of acute distal femur fractures above a total knee arthroplasty, Systematic review of 415 cases (1981–2006). Acta Orthop 2008: 79: 22–27. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the knee society clinical
rating system. Clin Orthop Relat Res 1989: 248: 13–14. Jassim SS, Douglas SL, Haddad FS. Athletic activity after lower limb arthroplasty: a systematic review of current evidence. Bone Joint J 2014: 96: 923–927. Jones DL, Cauley JA, Kriska AM, Wisniewski SR, Irrgang JJ, Heck DA, Kwoh CK, Crossett LS. Physical activity and risk of revision total knee arthroplasty in individuals with knee osteoarthritis: a matched case control study. J Rheumatol 2004: 31: 1384–1390. Keren A, Berkovich Y, Soudry M. Sport activity after hip and knee arthroplasty. Harefuah 2013: 152: 649–653. Kösters A, Pötzelsberger B, Dela F, Dorn U, Hofstädter T, Fink C, Müller E. Alpine Skiing With total knee ArthroPlasty (ASWAP): study design and intervention. Scand J Med Sci Sports 2015: 25 (Suppl. 2): 3–9. Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clin Orthop Relat Res 2009: 467: 2606–2612.
Outcome after skiing with total knee arthroplasty Kurtz SM, Ong KL, Lau E, Bozic KJ. Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021. J Bone Joint Surg Am 2014: 96: 624–630. Lavernia CJ, Sierra RJ, Hungerford DS, Krackow K. Activity level and wear in total knee arthroplasty: a study of autopsy retrieved specimens. J Arthroplasty 2001: 16: 446–453. Leino OK, Lempainen L, Virolainen P, Sarimo J, Pölönen T, Mäkelä KT. Operative results of periprosthetic fractures of the distal femur in a single academic unit. Scand J Surg 2014: pii: 1457496914552343. Long WJ, Bryce CD, Hollenbeak CS, Benner RW, Scott WN. Total knee replacement in young, active patients: long-term follow-up and functional outcome: a concise follow-up of a previous report. J Bone Joint Surg Am 2014: 17 (96): e159. McGrory BJ. Periprosthetic fracture of the femur after total hip arthroplasty occurring in winter activities: report of two cases. J Surg Orthop Adv 2004: 13: 119–123. Marker DR, Mont MA, Seyler TM, McGrath MS, Kolisek FR, Bonutti PM. Does functional improvement following TKA correlate to increased sports activity? Iowa Orthop J 2009: 29: 11–16. Mayr HO, Reinhold M, Bernstein A, Suedkamp NP, Stoehr A. Sports activity following total knee arthroplasty in patients older than 60 years. J Arthroplasty 2015: 30: 46–49. Mody BS, Mody K. Arthroplasty in young adults: options, techniques, trends, and results. Curr Rev Musculoskelet Med 2014: 7: 131–135. Mont MA, Lee CW, Sheldon M, Lennon WC, Hungerford DS. Total knee arthroplasty in patients < 50 years old. J Arthroplasty 2002a: 17: 538–543. Mont MA, Rajadhyaksha AD, Marxen JL, Silberstein CE, Hungerford DS. Tennis after total knee arthroplasty. Am J Sports Med 2002b: 30: 163–166. Mont MA, Marker DR, Seyler TM, Gordon N, Hungerford DS, Jones LC.
Knee arthroplasties have similar results in high- and low-activity patients. Clin Orthop Relat Res 2007: 460: 165–173. Mont MA, Marker DR, Seyler TM, Jones LC, Kolisek FR, Hungerford DS. High-impact sports after total knee arthroplasty. J Arthroplasty 2008: 23: 80–84. Müller E, Gimpl M, Poetzelsberger B, Finkenzeller T, Scheiber P. Salzburg Skiing for the Elderly Study: study design and intervention. Health benefit of alpine skiing for elderly. Scand J Med Sci Sports 2011: 21 (Suppl. 1): 1–8. Niederle P, Knahr K. Sporting activities following total hip and knee arthroplasty. Wien Med Wochenschr 2007: 157: 2–6. OECD. Hip and knee replacement. In: Health at a glance: Europe 2012. Paris: OECD Publishing. http://dx.doi.org/10 .1787/9789264183896-37-en. Ollivier M, Frey S, Parratte S, Flecher X, Argenson JN. Does impact sport activity influence total hip arthroplasty durability? Clin Orthop Relat Res 2012: 470: 3060–3066. Popoola OO, Yao JQ, Johnson TS, Blanchard CR. Wear, delamination, and fatigue resistance of melt-annealed highly crosslinked UHMWPE cruciate-retaining knee inserts under activities of daily living. J Orthop Res 2010: 28: 1120–1126. Pötzelsberger B, Lindinger SJ, Stöggl T, Buchecker M, Müller E. Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on gait asymmetries. Scand J Med Sci Sports 2015: 25 (Suppl. 2): 49–59. Richmond SA, Fukuchi RK, Ezzat A, Schneider K, Schneider G, Emery CA. Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review. J Orthop Sports Phys Ther 2013: 43: 515–519. Rorabeck CH, Taylor JW. Periprosthetic fractures of the knee complicating total knee arthroplasty. Orthop Clin North Am 1999: 30: 265–277. Savin L, Barha˘ros¸ie C, Botez P. Periprosthetic femoral fractures – evaluation of risk factors. Rev Med
Chir Soc Med Nat Iasi 2012: 116: 846–852. Schmalzried TP, Szuszczewicz ES, Northfield MR, Akizuki KH, Frankel RE, Belcher G, Amstutz HC. Quantitative assessment of walking activity after total hip or knee replacement. J Bone Joint Surg Am 1998: 80: 54–59. Scuderi GR, Bourne RB, Noble PC, Benjamin JB, Lonner JH, Scott WN. The new knee society knee scoring system. Clin Orthop Relat Res 2012: 470: 3–19. Seyler TM, Mont MA, Ragland PS, Kachwala MM, Delanois RE. Sports activity after total hip and knee arthroplasty: specific recommendations concerning tennis. Sports Med 2006: 36: 571–583. Singh SP, Bhalodiya HP. Outcome and incidence of periprosthetic supracondylar femoral fractures in TKA. Indian J Orthop 2013: 47: 591–597. Statistik Austria. Anzahl der unterschiedlichen medizinischen Einzelleistungen bei Spitalsentlassungen 2009 bis 2013, 2009–2013. http://www.statistik.at/web_de/ statistiken/gesundheit/stationaere _aufenthalte/medizinische_leistungen/ index.html. Tegner Y, Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 1985: 198: 43–49. Trousdale RT, McGrory BJ, Berry DJ, Becker MW, Harmsen WS. Patients’ concerns prior to undergoing total hip and total knee arthroplasty. Mayo Clin Proc 1999: 74: 978–982. Whitehouse MR, Mehendale S. Periprosthetic fractures around the knee: current concepts and advances in management. Curr Rev Musculoskelet Med 2014: 7: 136–144. Woon RP, Amstutz HC. High performance of metal-on-metal bearings: a case report. J Surg Orthop Adv 2012: 21: 170–175. Wylde V, Blom A, Dieppe P, Hewlett S, Learmonth I. Return to sport after joint replacement. J Bone Joint Surg Br 2008: 90: 920–923.
15
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Alpine Skiing With total knee ArthroPlasty (ASWAP): clinical and radiographic outcomes T. Hofstaedter1, C. Fink2, U. Dorn1, B. Pötzelsberger3, C. Hepperger2, K. Gordon1, E. Müller3 University Clinic of Orthopaedics, PMU Salzburg, Salzburg, Austria, 2Sportsclinic Austria, Innsbruck, Austria, 3Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria Corresponding author: Thomas Hofstaedter, MBA, Department of Orthopaedic Surgery, PMU Salzburg, Landeskrankenhaus Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria. Tel: +43 662 4482 57322, E-mail: [email protected]
1
Accepted for publication 4 March 2015
The aim of the study was to assess the effect of a recreational alpine skiing intervention on implant-related factors, such as loosening and wear, in patients with total knee arthoplasty (TKA). A group of 16 TKA patients were examined 2.3 ± 0.1 years after skiing about 80 days over three seasons inclusive of a ski intervention of 2–3 times per week (25.5 days) over a 12-week period. Mean follow-up period was 5.1 ± 1 years after surgery. All patients had excellent clinical and radiological outcomes. The average flexion was 120–130°, the average Oxford
Knee Score increased from 15 points pre-operatively to 47.4 points post-operatively. An average Tegner activity level of 5.5 was assessed, indicating a very high postoperative activity level. No radiolucencies or osteolyses were observed in any of the radiographs. One patient sustained a meniscal tear in the contralateral knee. Recreational alpine skiing on intermediate terrain at moderate speed can be recommended after TKA. Analysis of mid-term follow-up has not shown any negative effect on the implant loosening or additional polyethylene wear.
The primary objective of total knee arthroplasty (TKA) is to decrease pain, restore a functional knee joint, and improve patients’ quality of life. However, patients’ and surgeons’ expectations today are higher than those of years ago; this includes long-term implant survivors and participation in sports activities, including some highimpact sports. The demand for total joint arthroplasty is rising, being particularly high in Western Europe and Northern America. In particular, the demand in patients younger than 65 years will increase (Kurtz et al., 2009; Mody & Mody, 2014). In the United States, the total number of procedures increased by 6.0% for primary total hip arthroplasty (THA) and 6.1% for primary TKA from 2009 to 2010 (Kurtz et al., 2014). In Austria, total knee replacements (TKR) increased by 11% from 2009 to 2013 (Statistik Austria, 2009–2013), although this is one of the countries with the highest rates of knee and hip replacements in Europe (249/100 000 people had hip replacements in 2010 and 201/100 000 people had knee replacements in 2010; OECD, 2012). The reason is not only an increased life expectancy and population growth but also an increasing number of younger patients who undergo the operation. Osteoarthritis is mainly associated with age, but it is also associated with genetic factors, obesity, lifestyle, and sports activity (Richmond et al., 2013). The populations’ increasing
activity levels leads to a decreased inhibition threshold of undergoing joint arthroplasty. This leads to an increasing number of TKA patients between 40 and 60 years of age. Younger patients are usually more physically active; therefore, expectations following TKA are generally higher than the expectations of older patients. Nevertheless, there is also a growing number of senior citizens hoping to live a more active lifestyle after undergoing total joint replacement (TJR; Trousdale et al., 1999). Although the primary goals for the younger age group are similar regarding pain relief and restoration of function, younger patients additionally expect a quick recovery, return to activities of daily living, and no limitations of their desired sport activities. However, based on our own experience, expectations of patients undergoing TJR are generally changing, regardless of the patient’s age, sex, or culture. In all age groups, patients tend to be more active. Sport has become an essential part of life, not only because of an increased quality of life and health but also because it is an important factor for maintaining social relationships. Therefore, we must accept the patient’s desire to not quit sports after undergoing TJR. Wylde et al. (2008), for example, reported a rate of approximately 35% of patients participating in sports before undergoing surgery, with 61.4% of those patients returning to their sporting activity after surgery.
10
Outcome after skiing with total knee arthroplasty However, some questions need to be answered: Are sporting activities, particularly high-impact sports, recommendable after hip or knee replacement? Does high activity lead to early loosening of the prostheses or to premature polyethylene wear? Only a few studies have identified the influence of high-impact sports on TKA (Mont et al., 2002a, b, 2008; Seyler et al., 2006; Keren et al., 2013; Mayr et al., 2015) and some physicians continue to have concerns about sports activity after TKA. Recommendations from orthopedic societies either do not exist or are limited; these recommendations are normally based on surgeons’ surveys and not on hard evidence. Despite the lack of data and evidence, there is a trend for surgeons to allow more sports activities after TJR. From 1999 to 2005, the number of sport activities “not recommended” by the American Knee Society members decreased from 12 to 5; the numbers of “allowed” activities increased from 18 to 19 (Healy et al., 2008). This trend seems to continue when asking colleagues about their recommendations for their patients’ sports habits. Reasons might be new developments such as new bearing surfaces (e.g., highly crosslinked polyethylene), implant coats, or new implant designs. Increased polyethylene wear has always been considered to be associated with high activity (Schmalzried et al., 1998; Gschwend et al., 2000; Lavernia et al., 2001; Hamai et al., 2008; Ollivier et al., 2012). However, there are also contradicting studies, which have documented no negative influence of sports activities on polyethylene wear (Mont et al., 2002a, b; Abe et al., 2014). With more frequent use of highly cross-linked polyethylene, loosening caused by polyethylene wear should be significantly reduced (Popoola et al., 2010). Surgeons are not only concerned about the risk of early prosthetic loosening associated with high-impact sports, but also about the increased risk of injury. Although it is a very rare complication, suffering a periprosthetic fracture while participating in sports activities is possible (McGrory, 2004). A periprosthetic fracture is a major complication and is associated with high morbidity and mortality (Bhattacharyya et al., 2007). These fractures are difficult to treat and require complex surgeries and therapeutic strategies. Because there is a lack of objective data regarding the effects of sports participation on the outcomes of arthroplasty, the goal of this study was to evaluate the risk of alpine skiing in patients with TKA. Material and methods Indications for total knee replacement include degenerative osteoarthritis in all patients. The details regarding the study design and participants are presented elsewhere by Kösters et al. (2015). Patients were selected from the patient’s knee arthroplasty lists of the Orthopaedic University Clinic, Salzburg and the Sportsclinic, Austria. Individuals were required to meet the following criteria: 1 to 5 years post-operative; age 60–80; intermedi-
ate level skier; no previous arthroplasties performed (e.g., hip or shoulder arthroplasty); no pain or functional limitation of the operated knee; no radiographic findings of aseptic loosening; no other severe osteoarthritis, pain, or functional limitation of the musculo-skeletal system which may have negatively affected intensity of skiing. For our study question, we also included patients with bilateral TKA. A total of 16 patients (11 from the Salzburg group, 5 from the Innsbruck group) demonstrating willingness to regularly ski (2–3 days/week, 3–4 h/day) for 12 weeks (an average of 25.5 days all together) were included in the intervention group (IG). They completed an average of 3393 vertical meters of downhill skiing, with a total skiing distance of 33.6 km/day (Kösters et al., 2015). Another 11 patients fulfilled the inclusion criteria but were not willing to ski regularly; as such, these patients were assigned to the control group (CG; Kösters et al., 2015). In this paper, we will not expand on the CG because of the irrelevance of this group regarding the orthopedic questions addressed in this paper. Fifteen patients (5 females, 11 males) were treated with a knee prosthesis from Zimmer Inc. (Warsaw, IN, USA) [NexGen Cruciate retaining (CR) knee in 10 patients and Nex Gen Ligamentum posterior stabilized (LPS) knee (both prostheses are mobile fixed components) in five patients], whereas one patient received a LCS knee from Depuy Inc. (Warsaw, IN, USA) (mobile bearing component). One patient received bilateral knee arthroplasties (Nex Gen CR knee of Zimmer Lto), and two patients received additional replacements of the patella. All TKAs were performed over a standard medial parapatellar approach. The average age at time of the skiing intervention was 69.8 ± 4.4 years. The average period of intervention was 2.7 ± 1 years post-operative. The average follow-up period was 5.1 ± 1 years post-operative. The follow-up after skiing intervention was 2.3 ± 0.1 years. During the follow-up time, most patients had already gone skiing an additional two winter seasons, with several skiing days (average 20 skiing days/year); all together, the last follow-up was after approximately 80 skiing days. The intervention program consisted of 2–3 days skiing per week over a period of 12 weeks (Kösters et al., 2015). The study participants were divided into three groups according to the region (Innsbruck and Salzburg); in addition, the Salzburg group was also assigned to one of two homogeneous groups, based on their skiing skills. The groups skied each day using a “Guided Skiing” format, with each group lead by one ski instructor. At the time of follow-up, patients were examined clinically and had radiographs taken (anterior/posterior, lateral view, and patella tangential view). At the same time, knee and functional scores were calculated using the Oxford Knee Score, the Knee Society Score, and the Tegner activity level (Tegner & Lysholm, 1985; Insall et al., 1989; Dawson et al., 1998).
Results Every patient included in the study was willing to present at follow-up [5.1 ± 1 (mean ± SD) and 2.3 ± 0.1 years post-operatively and post-intervention, respectively]. All patients were evaluated clinically and radiologically at the two involved orthopedic clinics in Salzburg and Innsbruck. Knee function The clinical examination at follow-up revealed very good to excellent knee function in all patients. The average flexion was between 120° and 130°, and no patient had a limited flexion less than 115°. The average
11
Hofstaedter et al. Oxford Knee Score was 47.4, which was compared with the pre-operative score of 15. The average Tegner activity level was 5.5, which is indicative of a very high post-operative activity level. The Knee Society Score at the time of follow-up was 97.2 (Knee Society Score data collected only in the Salzburg group, which included 11 skiers, and was not evaluated pre-intervention).
Radiological assessment All patients consented to a radiological examination, pre- and post-interventional, at follow-up. No patient showed a reduction in the height of the polyethylene inlay in the postero-anterior view. No radiolucent lines were found between the prosthesis and bone. No osteolyses were detectable (Fig. 1).
Complications One patient who was originally included in the IG had to be excluded from the study because this patient sustained a periprosthetic femur fracture while skiing independently of the study; this was prior to the start of the study. He was successfully operated on with a plate and continued his ski activity the following winter. One patient had to interrupt skiing for a number of days because of a torn meniscus in the contralateral knee, which was treated conservatively. Another patient had to stop skiing after 8 days because of cardiovascular problems. This patient also moved on to regular skiing the following winter. No significant injury was observed during the intervention. Discussion Performing sports after TJR has grown more and more important during the last few years (Healy et al., 2008). Several reports are concerned with the outcomes of TJR in patients participating in sports. Just a few studies concentrate on high-impact sports in patients with TKA or THA (Bradbury et al., 1998; Bock et al., 2003; Niederle & Knahr, 2007) and even less focus on alpine skiing (Gschwend et al., 2000; Müller et al., 2011; Woon & Amstutz, 2012). To our knowledge, this is the first study to determine the effect of alpine skiing on TKA in a larger patient population, also analyzing further parameters during pre-, post-, and retention-test sessions (see: Kösters et al., 2015). After an average 25.5 days of skiing and despite the fact that all patients additionally went skiing prior to and after the intervention on a private basis, all patients showed an excellent clinical and radiographic outcome, with an average flexion between 120° and 130°, an average Oxford Knee Score of 47.4, an average Tegner activity level of 5.5, and a Knee Society Score of 97.2.
12
Fig. 1. Knee radiographs of a 68-year-old male with severe osteoarthritis of the left knee, treated with TKA (Zimmer Nex Gen LPS). This patient additionally received a patella replacement. Left knee anterior/posterior (a) and lateral view (b) preoperatively; 5/2010. Severe osteoarthritis with joint space narrowing and meniscal calcifications as well as retropatellar arthritis. Left knee anterior/posterior (c) and lateral view (d) at FU 12/2011 (1.5 years post-operatively, before skiing intervention). No radiolucencies detectable. Left knee anterior/posterior (e) and lateral view (f) at FU 7/2014 (4.1 years post-operatively, 2.4 years after skiing intervention). No radiolucencies detectable. No change in polyethylene height compared with preintervention X-ray (c, d).
Outcome after skiing with total knee arthroplasty The Oxford Knee Score is a patient-reported outcome score, which was specifically developed to assess the necessity of undergoing TKR and to measure the outcome after TKR. Anyone with an Oxford Knee Score below 20 may be referred for TKR and a score over 40 may indicate satisfactory joint function. An average Oxford Knee Score of 47.4 is indicative of an excellent outcome after TKA. The Knee Society Score was developed as a simple, objective scoring system to rate the knee and patient’s functional abilities such as walking and stair climbing before and after TKA (Scuderi et al., 2012). It is the most popular score to evaluate outcomes after TKA. A score over 80 points is indicative of an excellent outcome after TKA. The Tegner activity level scale is a valid measure of return to activity after injuries or operations. The score varies from 0 to 10. An average of 5.5 points is indicative for a high activity level after TKA like work-heavy labor, competitive sport cycling, or tennis. Not showing any signs of early prosthetic loosening or increased polyethylene wear at midterm follow-up, and resulting in e.g., improved gait performance with a reduction in gait asymmetry (see Pötzelsberger et al., 2015), we conclude that recreational alpine skiing can be safely performed in pre-operatively sportive patients. In a recently published systematic review, Jassim et al. (2014) concluded that especially young, pre-operatively active patients were able to return to sports activities after TJR, although intensity of activities tended to be less post-operatively. Active patients scored higher Knee Society Scores than sedentary ones (85.2 vs 83.4 points, respectively) after an average of 74 months postoperatively, and rates of implant failures were not increased (Bock et al., 2003; Jassim et al., 2014). When comparing sports activity levels, patients who required revision surgery were less active than patients without failed knee prosthesis (Jones et al., 2004). Mont et al. (2007) reported similar results in high and low activity patients with TKA after a mean follow-up period of 7 years, without any signs of progressive radiolucencies or osteolysis in either group. Patients with THA participating in alpine or crosscountry skiing did not show increased numbers of aseptic loosening, but an increased average wear rate after 10 years in highly physically active patients – Gschwend et al. (2000); therefore, they recommended controlled alpine or cross-country skiing. We did not find any surveys concerned with wear rates in TKA associated with high-impact sports. In general, knee functional scores improve after TKR. Long et al. (2014) report a mean Tegner score improving from 1.5 points to 3.0 post-operatively, with an average Knee Society Score of 87.4 points post-operatively. Post-operative improvement in Knee Society Score reached a mean of 48 points after undergoing TKA (Marker et al., 2009; Long et al., 2014).
However, sports activity decreases after undergoing TKR surgery (Bradbury et al., 1998; Chatterji et al., 2005; Dahm et al., 2008). Nevertheless, some of those patients who want to return to high-impact sports after TKA – based on the present results and those of past studies – can enjoy excellent clinical outcomes for at least 2.3 ± 0.1 years afterwards. Mont et al. (2008) gave similar recommendations for a follow-up period of 4 years in patients with TKA performing different kinds of high-impact sports on average four times per week – among those were three cross-country skiers. Of those 33 patients, 32 had a Knee Society Score greater than 80 points, with a mean range of motion of 119° (range, 105–130) at final follow-up. Concerned with implant loosening, Mayr et al. (2015) examined a total of 81 patients performing sports activity after TKA, with 25% of them performing high-impact sports. Even at a mean follow-up of 6.4 years, no individual showed evident signs of wear or component loosening. Limiting is the fact that for the study’s orthopedic approach, we did not compare radiographic results with those of matched patients not practicing alpine skiing or other high-impact activities. Knee Society Scores were not evaluated post-intervention in all patients and were not evaluated pre-intervention; therefore, a comparison of the scores before and after the average 80 days of skiing was not possible – we can hereby not objectify whether patients’ scores improved after alpine skiing or not, despite good clinical and radiographic outcomes. Also, we did not follow our patients long enough to give clear recommendations concerning high-demand activities after TKR and their long-term influences on implant survival. A long-term follow-up study would be necessary to clarify such effects. In most studies, the intensity level of sports activities was not evaluated. In our survey, patients skied with a skiing instructor every day. Skiing intensity throughout the groups was therefore uniform. It should be strongly kept in mind, that besides having a possible influence on implant loosening, high-impact sports may increase the risk of injuries associated with TJR. Periprosthetic fractures are among the major and most dreaded complications after TJR with an incidence of 0.58% to 2.5% after TKA (Rorabeck & Taylor, 1999; Singh & Bhalodiya, 2013). The main risk factors for periprosthetic fractures are rheumatoid polyarthritis, severe osteoporosis, implant loosening, revision surgery, and significant anatomical deformities (Della Rocca et al., 2011; Savin et al., 2012; Whitehouse & Mehendale, 2014). Savin et al. (2012) report that most of the fractures are the result of minor trauma caused by a same-level fall. However, very physically active patients are especially at risk of suffering a periprosthetic fracture while doing sports (Savin et al., 2012; Whitehouse & Mehendale, 2014).
13
Hofstaedter et al. There was one patient who should have been included in the IG in the present study but who suffered a periprosthetic supracondylar femur fracture before the intervention started. Technically, it occurred while skiing, but he was actually standing still on the skis when he was hit by a skier from above. Periprosthetic fractures are major complications and mostly require a challenging operative treatment with high post-operative complication rates including, e.g., infections, non-union and early loosening, resulting in the need for further revision surgery (Herrera et al., 2008; Leino et al., 2014). According to the radiographic and clinical outcomes in all 16 patients during a post-interventional follow-up period of 2.3 ± 0.1 years, guided alpine skiing with TKA is not associated with increased rates of implant loosening, wear, or osteolysis. Skiing with TKA can be recommended in pre-operatively physically active patients who show good functional postoperative outcomes without any signs of loosening on radiographic evaluation. We classified a good functional outcome as a painless knee prosthesis without severe flexion contractures, limited range of motion, or severe ligamentous instability. By all means, it is most important to inform patients about the risk of severe injuries associated with an artificial joint, such as periprosthetic fractures, which are particularly difficult to treat.
Patients should be sensitized to the higher risk of loosening and wear associated with sports activities of high intensity and the necessity for revision surgery with implant loosening or periprosthetic fractures. Recommendations must be individualized and have to meet the increasing demand of patients to return to sports after surgery. However, questions remain: are orthopedic surgeons able to fulfill these demands and can prosthetic designs fulfill these demands without the risk of early aseptic loosening?
Perspectives The demand for TKA worldwide will further increase over the next decades. The challenge for surgeons and prosthetic manufacturers will be to fulfill the patients’ demands of continuing high-impact sports after TKA. With more frequent use of highly cross-linked polyethylene, loosening caused by polyethylene wear should be significantly reduced. Additionally, new prosthetic designs have been introduced to the market in the last few years. Key words: Alpine radiolucency.
skiing,
knee
replacement,
References Abe H, Sakai T, Nishii T, Takao M, Nakamura N, Sugano N. Jogging after total hip arthroplasty. Am J Sports Med 2014: 42 (1): 131–137. Bhattacharyya T, Chang D, Meigs JB, Estok DM, Malchau H. Mortality after periprosthetic fracture of the femur. J Bone Joint Surg Am 2007: 89: 2658–2662. Bock P, Schatz K, Wurnig C. Physical activity after total knee replacement. Z Orthop Ihre Grenzgeb 2003: 141 (3): 272–276. Bradbury N, Borton D, Spoo G, Cross MJ. Participation in sports after total knee replacement. Am J Sports Med 1998: 26: 530–535. Chatterji U, Ashworth MJ, Lewis PL, Dobson PJ. Effect of total knee arthroplasty on recreational and sporting activity. ANZ J Surg 2005: 75: 405–408. Dahm DL, Barnes SA, Harrington JR, Sayeed SA, Berry DJ. Patient-reported activity level after total knee arthroplasty. J Arthroplasty 2008: 23: 401–407. Dawson J, Fitzpatrick R, Murray D, Carr A. Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br 1998: 80: 63–69.
14
Della Rocca GJ, Leung KS, Pape HC. Periprosthetic fractures: epidemiology and future projections. J Orthop Trauma 2011: 25 (Suppl. 2): S66–S70. Gschwend N, Frei T, Morscher E, Nigg B, Loehr J. Alpine and cross-country skiing after total hip replacement 2 cohorts of 50 patients each, one active, the other inactive in skiing, followed for 5–10 years. Acta Orthop Scand 2000: 71: 243–249. Hamai S, Miura H, Higaki H, Shimoto T, Matsuda S, Okazaki K, Iwamoto Y. Three-dimensional knee joint kinematics during golf swing and stationary cycling after total knee arthroplasty. J Orthop Res 2008: 26: 1556–1561. Healy WL, Sharma S, Schwartz B, Iorio R. Athletic activity after total joint arthroplasty. J Bone Joint Surg Am 2008: 90: 2245–5. Herrera DA, Kregor PJ, Cole PA, Levy BA, Jönsson A, Zlowodzki M. Treatment of acute distal femur fractures above a total knee arthroplasty, Systematic review of 415 cases (1981–2006). Acta Orthop 2008: 79: 22–27. Insall JN, Dorr LD, Scott RD, Scott WN. Rationale of the knee society clinical
rating system. Clin Orthop Relat Res 1989: 248: 13–14. Jassim SS, Douglas SL, Haddad FS. Athletic activity after lower limb arthroplasty: a systematic review of current evidence. Bone Joint J 2014: 96: 923–927. Jones DL, Cauley JA, Kriska AM, Wisniewski SR, Irrgang JJ, Heck DA, Kwoh CK, Crossett LS. Physical activity and risk of revision total knee arthroplasty in individuals with knee osteoarthritis: a matched case control study. J Rheumatol 2004: 31: 1384–1390. Keren A, Berkovich Y, Soudry M. Sport activity after hip and knee arthroplasty. Harefuah 2013: 152: 649–653. Kösters A, Pötzelsberger B, Dela F, Dorn U, Hofstädter T, Fink C, Müller E. Alpine Skiing With total knee ArthroPlasty (ASWAP): study design and intervention. Scand J Med Sci Sports 2015: 25 (Suppl. 2): 3–9. Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ. Future young patient demand for primary and revision joint replacement: national projections from 2010 to 2030. Clin Orthop Relat Res 2009: 467: 2606–2612.
Outcome after skiing with total knee arthroplasty Kurtz SM, Ong KL, Lau E, Bozic KJ. Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021. J Bone Joint Surg Am 2014: 96: 624–630. Lavernia CJ, Sierra RJ, Hungerford DS, Krackow K. Activity level and wear in total knee arthroplasty: a study of autopsy retrieved specimens. J Arthroplasty 2001: 16: 446–453. Leino OK, Lempainen L, Virolainen P, Sarimo J, Pölönen T, Mäkelä KT. Operative results of periprosthetic fractures of the distal femur in a single academic unit. Scand J Surg 2014: pii: 1457496914552343. Long WJ, Bryce CD, Hollenbeak CS, Benner RW, Scott WN. Total knee replacement in young, active patients: long-term follow-up and functional outcome: a concise follow-up of a previous report. J Bone Joint Surg Am 2014: 17 (96): e159. McGrory BJ. Periprosthetic fracture of the femur after total hip arthroplasty occurring in winter activities: report of two cases. J Surg Orthop Adv 2004: 13: 119–123. Marker DR, Mont MA, Seyler TM, McGrath MS, Kolisek FR, Bonutti PM. Does functional improvement following TKA correlate to increased sports activity? Iowa Orthop J 2009: 29: 11–16. Mayr HO, Reinhold M, Bernstein A, Suedkamp NP, Stoehr A. Sports activity following total knee arthroplasty in patients older than 60 years. J Arthroplasty 2015: 30: 46–49. Mody BS, Mody K. Arthroplasty in young adults: options, techniques, trends, and results. Curr Rev Musculoskelet Med 2014: 7: 131–135. Mont MA, Lee CW, Sheldon M, Lennon WC, Hungerford DS. Total knee arthroplasty in patients < 50 years old. J Arthroplasty 2002a: 17: 538–543. Mont MA, Rajadhyaksha AD, Marxen JL, Silberstein CE, Hungerford DS. Tennis after total knee arthroplasty. Am J Sports Med 2002b: 30: 163–166. Mont MA, Marker DR, Seyler TM, Gordon N, Hungerford DS, Jones LC.
Knee arthroplasties have similar results in high- and low-activity patients. Clin Orthop Relat Res 2007: 460: 165–173. Mont MA, Marker DR, Seyler TM, Jones LC, Kolisek FR, Hungerford DS. High-impact sports after total knee arthroplasty. J Arthroplasty 2008: 23: 80–84. Müller E, Gimpl M, Poetzelsberger B, Finkenzeller T, Scheiber P. Salzburg Skiing for the Elderly Study: study design and intervention. Health benefit of alpine skiing for elderly. Scand J Med Sci Sports 2011: 21 (Suppl. 1): 1–8. Niederle P, Knahr K. Sporting activities following total hip and knee arthroplasty. Wien Med Wochenschr 2007: 157: 2–6. OECD. Hip and knee replacement. In: Health at a glance: Europe 2012. Paris: OECD Publishing. http://dx.doi.org/10 .1787/9789264183896-37-en. Ollivier M, Frey S, Parratte S, Flecher X, Argenson JN. Does impact sport activity influence total hip arthroplasty durability? Clin Orthop Relat Res 2012: 470: 3060–3066. Popoola OO, Yao JQ, Johnson TS, Blanchard CR. Wear, delamination, and fatigue resistance of melt-annealed highly crosslinked UHMWPE cruciate-retaining knee inserts under activities of daily living. J Orthop Res 2010: 28: 1120–1126. Pötzelsberger B, Lindinger SJ, Stöggl T, Buchecker M, Müller E. Alpine Skiing With total knee ArthroPlasty (ASWAP): effects on gait asymmetries. Scand J Med Sci Sports 2015: 25 (Suppl. 2): 49–59. Richmond SA, Fukuchi RK, Ezzat A, Schneider K, Schneider G, Emery CA. Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review. J Orthop Sports Phys Ther 2013: 43: 515–519. Rorabeck CH, Taylor JW. Periprosthetic fractures of the knee complicating total knee arthroplasty. Orthop Clin North Am 1999: 30: 265–277. Savin L, Barha˘ros¸ie C, Botez P. Periprosthetic femoral fractures – evaluation of risk factors. Rev Med
Chir Soc Med Nat Iasi 2012: 116: 846–852. Schmalzried TP, Szuszczewicz ES, Northfield MR, Akizuki KH, Frankel RE, Belcher G, Amstutz HC. Quantitative assessment of walking activity after total hip or knee replacement. J Bone Joint Surg Am 1998: 80: 54–59. Scuderi GR, Bourne RB, Noble PC, Benjamin JB, Lonner JH, Scott WN. The new knee society knee scoring system. Clin Orthop Relat Res 2012: 470: 3–19. Seyler TM, Mont MA, Ragland PS, Kachwala MM, Delanois RE. Sports activity after total hip and knee arthroplasty: specific recommendations concerning tennis. Sports Med 2006: 36: 571–583. Singh SP, Bhalodiya HP. Outcome and incidence of periprosthetic supracondylar femoral fractures in TKA. Indian J Orthop 2013: 47: 591–597. Statistik Austria. Anzahl der unterschiedlichen medizinischen Einzelleistungen bei Spitalsentlassungen 2009 bis 2013, 2009–2013. http://www.statistik.at/web_de/ statistiken/gesundheit/stationaere _aufenthalte/medizinische_leistungen/ index.html. Tegner Y, Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 1985: 198: 43–49. Trousdale RT, McGrory BJ, Berry DJ, Becker MW, Harmsen WS. Patients’ concerns prior to undergoing total hip and total knee arthroplasty. Mayo Clin Proc 1999: 74: 978–982. Whitehouse MR, Mehendale S. Periprosthetic fractures around the knee: current concepts and advances in management. Curr Rev Musculoskelet Med 2014: 7: 136–144. Woon RP, Amstutz HC. High performance of metal-on-metal bearings: a case report. J Surg Orthop Adv 2012: 21: 170–175. Wylde V, Blom A, Dieppe P, Hewlett S, Learmonth I. Return to sport after joint replacement. J Bone Joint Surg Br 2008: 90: 920–923.
15
