Original Article
407
Outcomes after Knee Microfracture of Chondral Defects in Alpine Ski Racers J. Richard Steadman, MD1 Chad M. Hanson, MD2 Evan W. James, BS1 Alyson Guillet, MD1 1 Center for Outcomes-Based Orthopaedic Research (COOR),
Steadman Philippon Research Institute, Vail, Colorado 2 Desert Orthopaedic Center, Henderson, Nevada
Karen K. Briggs, MPH1
Lauren M. Matheny, BA1
Address for correspondence J. Richard Steadman, MD, Center for Outcomes-Based Orthopaedic Research, Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657 (e-mail: [email protected]).
Abstract
Keywords
► ► ► ►
articular cartilage microfracture alpine ski racers outcomes
Articular cartilage defects of the knee have been shown to cause pain, swelling, decreased function, and suboptimal athletic performance. Treatment of elite-level athletes presenting with full-thickness chondral defects of the knee continues to be a challenge for orthopedic surgeons. The purpose of this study was to document outcomes in elite professional alpine ski racers after microfracture surgery. This study was approved by an institutional review board. All patients who competed in professional ski races recognized by International Ski Federation and had a full-thickness knee articular cartilage defect, treated with microfracture, by a single surgeon, were included in the study. All data were collected prospectively. At minimum 2 years following microfracture, all patients completed a questionnaire, including Lysholm score, Tegner activity scale, and patient satisfaction with outcome. Minimum 2-year follow-up was available for 18 of 20 skiers (90%) at an average follow-up of 77 months (range, 24–255 months). Size of knee articular cartilage defect was larger in males (195 mm2) compared with females (155 mm2); however, this difference was not statistically significant (p > 0.05). Median postoperative Tegner activity scale was 10 (range, 4– 10). Mean postoperative Lysholm score was 86 (range, 41–100). Median postoperative patient satisfaction score was 10 (range, 9–10). Out of the 20 skiers, 19 (95%) returned to competitive skiing. The age of the skier who did not return was 28 years. The average time from surgery to return to competition was 13.4 months (range, 0.5–25.3 months). Average end-of-season overall World Cup ranking was calculated for the nine skiers before and after surgery. Of these nine skiers, six had an improved average overall World Cup ranking after microfracture. In this study, patient satisfaction with outcome and function were high following microfracture of full-thickness chondral lesions of the knee. Nearly all skiers returned to full competition. Microfracture is an acceptable treatment option for elite skiers who have full thickness articular cartilage lesions of the knee.
Articular cartilage defects of the knee have been shown to cause pain, swelling, decreased function, and suboptimal athletic performance during sport participation.1–3 The treatment of elite-level athletes presenting with full-thickness chondral de-
fects of the knee continues to be a challenge for orthopedic surgeons.1–9 If left untreated, these defects rarely heal spontaneously due to the avascular nature of articular cartilage, whether the lesion is acute, chronic, or degenerative.1–7
received December 30, 2013 accepted March 6, 2014 published online May 22, 2014
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0034-1376330. ISSN 1538-8506.
Downloaded by: Rutgers University. Copyrighted material.
J Knee Surg 2014;27:407–410.
Microfracture in Alpine Ski Racers
Steadman et al.
In addition, these defects may predispose individuals to the development of knee osteoarthritis; which is why early intervention is recommended to mitigate this risk.10,11 Many different surgical treatments have been described for the treatment of full-thickness articular cartilage defects of the knee, including arthroscopic debridement, mosaicplasty, autologous chondrocyte implantation, and microfracture.12–17 The advantages of microfracture include the simplicity of the surgical technique, relatively low complication rates, and the low cost of the procedure.1,2 Good to excellent outcomes following microfracture for the treatment of articular cartilage defects have been reported, with patients returning to their desired activity level.1,2,14,18 Microfracture outcomes in the elite athlete have also been published for various sports, including professional football and basketball.3–6,8 However, documented outcomes following microfracture of the knee in the professional ski racer are limited. The purpose of this study was to document outcomes in elite professional alpine ski racers after microfracture surgery and a structured rehabilitation protocol.
Methods Patient Selection This study was approved by an institutional review board. Between 1986 and 2008, all patients who competed in professional ski races recognized by the International Ski Federation (FIS) and had a full-thickness articular cartilage defect of the knee, confirmed during arthroscopy, that was treated with microfracture, by a single surgeon, were identified. Patients were included in the study based on active ski competition immediately before surgery. Patients were excluded from this study if they were not at least 2 years out from surgery or had severe knee malalignment. In addition, patients who retired from professional skiing before surgery were also excluded from this study. Demographic data, detailed surgical findings, intraoperative data, and subjective data were collected prospectively for all patients and stored in a data registry. At a minimum 2 years following index microfracture surgery, all patients were asked to complete a questionnaire that included the Lysholm19 score to document function, the Tegner20 activity scale to document activity level, and a patient satisfaction with outcome question. Satisfaction was measured on a 10-point scale, with 10 equal to being very satisfied and 1 equal to being very unsatisfied with outcome. Return to sport was documented using ski race results published by FIS19 and was defined as participation in a ski race at any time after surgery that was recognized by the FIS Professional races which included the World Cup, European Cup, Nor-Am Cup, and Olympics. Statistical analysis was performed using SPSS for Windows (version 11.0, SPSS Inc., Chicago, IL).
Operative Technique All patients underwent knee arthroscopy with microfracture using the surgical technique as described by Steadman et al.13,15 Intra-articular evaluation of the articular cartilage defect was performed. Once the lesion was confirmed to be The Journal of Knee Surgery
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full thickness, the defect was prepared and measured. Next, multiple 3 to 4 mm deep microfracture holes were placed in a carefully spaced manner so as to be in close proximity to one another, without breaking into adjacent holes. Before the completion of the case, the arthroscopy pump pressure was reduced to ensure bleeding had occurred at the microfracture site. No drains were left within the joint. Over the subsequent weeks, all patients underwent a standardized postoperative rehabilitation program as described by Steadman et al.21,22 The rehabilitation of the tibiofemoral joint includes the use of a continuous passive motion machine for the first 6 weeks. Crutch-assisted weightbearing is prescribed for 8 weeks.13 As necessary, the program was supplemented to accommodate rehabilitation of concomitant ligamentous reconstructions completed at the time of microfracture.23
Rehabilitation Protocol for Patients with Patellofemoral Lesions All patients treated by microfracture for patellofemoral lesions must use a brace set at 0 to 20 degrees for at least 8 weeks. The brace limits compression of regenerating surfaces of the trochlea and patella. Passive motion with the brace removed is allowed, but otherwise, the brace must be worn at all times. Patients are placed into a continuous passive motion machine immediately after surgery. Cold therapy is also prescribed. Joint angles are carefully observed during arthroscopy to determine where the defect comes into contact with the patellar facet or the trochlear groove. We avoid these areas during strength training for approximately 4 months. This avoidance allows for training in the 0 to 20 degrees range immediately postoperatively because there is a minimal compression of these chondral surfaces with such limited motion. Patients are allowed weightbearing as tolerated in their brace 2 weeks after surgery. It is essential for patients to use a brace that prevents placing excessive shear force on the maturing marrow clot in the early postoperative period. We routinely lock the brace between 0 and 20 degrees range of motion to prevent flexion past the point where the median ridge of the patella engages the trochlear groove. After 8 weeks, the knee brace is gradually opened. When the brace is discontinued, patients are allowed to advance their training progressively. Stationary biking is allowed 2 weeks postoperatively, with increased resistance added at 8 weeks after microfracture. Starting 12 weeks after microfracture, the exercise program is the same one used for femorotibial lesions.21,22
Results A total of 20 patients (16 females and 4 males) with a mean age of 23 years (range, 15–29 years) met the inclusion criteria and were included in this study. Three patients had microfracture on both knees. No complications attributed to surgery were identified. One patient underwent microfracture of a bipolar or “kissing” lesion. The majority of lesions treated (62%) involved the lateral femoral condyle. The distribution of location of cartilage defects are listed in ►Table 1. Mean lesion size was 155 mm2 (range, 5–450 mm2).
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Table 1 Traumatic chondral defects in professional alpine ski racers Number of knees (n)
Patella
2
Lateral femoral condyle
13
Medial femoral condyle
3
Trochlear groove
1
Medial tibial plateau
0
Lateral tibial plateau
0
Lateral tibial plateau and lateral femoral condyle
1
Medial femoral condyle, patella, and trochlear groove
1
Outcome Scores Minimum 2-year follow-up was available for 18 of 20 skiers (90%) at an average follow-up of 6.4 years (range, 2.0–21.3 years). Median postoperative Tegner activity scale was 10 (range, 4–10). Mean postoperative Lysholm score was 86 (range, 41–100). Median postoperative patient satisfaction with outcome score was 10 (range, 9–10). Females had an average postoperative Lysholm score of 88 and males had an average postoperative Lysholm score of 91. Age was not associated with outcome scores, and there was no difference in outcome scores based on gender (p > 0.05). The size of the knee articular cartilage defect was larger in males (195 mm2) compared with females (155 mm2); however, this difference was not statistically significant (p > 0.05).
Return to Competition and Level of Performance Out of the 20 skiers, 19 (95%) returned to competitive skiing. The age of the skier who did not return was 28 years. The average time from surgery to return to competition was 13.4 months (range, 0.5–25.3 months). Males returned to skiing competitively in an average of 13.0 months and females returned in an average of 14.5 months. The 19 skiers who returned to competition all competed in FIS endorsed races. Athlete accomplishments after return to play included podium finishes in the European Cup, National Championships, World Cup, Nor Am Cup, and the Olympics. Data for overall World Cup rankings pre-microfracture and post-microfracture were available for nine skiers in the FIS’s database.24 Average end-of-season overall World Cup ranking was calculated for the nine skiers before and after surgery (►Fig. 1).24 Of these nine skiers, six had an improved average overall World Cup ranking after microfracture.
Discussion In this study, 19 of the 20 competitive skiers (95%) returned to competitive skiing following microfracture surgery for the treatment of a full-thickness articular cartilage defect. Patient satisfaction with outcome was excellent and knee function was high. Previous studies have reported conflicting results documenting return to sport after microfracture surgery, ranging from 44 to
Fig. 1 Average World Cup ranking pre- and post-microfracture for five athletes who we were able to extract rankings before and after surgery.
100% of athletes returning to sport competition.2–8 In a study that documented return to play following microfracture in professional football players, 76% of players returned to sport. Patients averaged playing an additional 4.6 seasons (56 more games) following microfracture surgery.4 In a similar study of professional basketball players, 19 of 24 players (79%) returned to sport after a mean of 7.5 months following microfracture surgery, which is similar to the results of our study.6 Previous studies have also shown that younger age is associated with better outcomes following microfracture.13,14,18,25 Mithoefer et al3 documented outcomes following microfracture of one or both of the femoral condyles, in athletes who participated in high-impact, pivoting sports. At a mean of 54 months, approximately 66% of patients, with a mean age of 38 years, reported good to excellent outcomes following microfracture. However, only 44% of their cohort returned to high-impact sports. Of this subset who returned to play, 57% reported performing at their preinjury level. Finally, 47% of the athletes reported a decline in function following their initial improvement. This study found that younger age and smaller lesion size was associated with better outcomes and microfracture was found to be an effective primary treatment of articular cartilage defects in the athletic knee.3 It is important to note that in this study, patients were non-weightbearing for 6 weeks instead of 8 weeks,21 which may explain the lower return to play percentage. Kreuz et al also studied the effect of age in 85 patients treated with microfracture and reported significantly better results in the modified Cincinnati knee and International Cartilage Repair Society scores in patients 40 years of age or younger.25 We observed similar improvements in function and satisfaction in our patient population, which, by nature of the sport, consists of relatively young athletes. Our study had a mean age of 23.1 years which may have contributed to the high rate of return to competition and favorable outcomes documented in this study. In our study, six of the nine skiers with overall World Cup rankings reported in the FIS database improved their average ranking after surgery, indicating that some ski racers not only returned to competition but excelled, and some athletes excelled beyond presurgery levels of performance. Various studies have documented good to excellent outcomes The Journal of Knee Surgery
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Defect location
Microfracture in Alpine Ski Racers
Steadman et al.
following knee microfracture; however, few studies have documented outcomes and return to competition in highlevel athletes, especially in this unique patient population. It is unclear why patients in this study had a higher percentage of athletes return to competitive sport than in several previous studies. Additional research is necessary to determine long-term outcomes in these elite athletes as they continue to progress in age. However, other studies did not use the same 8 weeks non-weightbearing guideline and other aspects of the rehabilitation protocol.
5
6
7
8
Limitations Our study has several limitations. This study was conducted at a referral clinic and is based on an elite level of athlete, and therefore may not be representative of the general patient population. This study was retrospective in nature; however, all data were collected prospectively. This study was relatively small due to the nature of the patients being studied. With data from the FIS, it was possible to document return to sport; however, it was difficult to compare best finishes at professional races pre- and postsurgery due to unreported results data in some cases, as well as intangible confounding variables in race location, conditions, and the competitiveness of the field across multiple years of competition. There is the possibility of gender bias, but this would be difficult to control in future studies due to the highly specific nature of the study population.
9
10
11
12
13
14
Conclusion In this study, patient satisfaction with outcome and function were high following microfracture of a full-thickness chondral lesion of the knee with structured rehabilitation. In addition, nearly all skiers returned to full competition. Microfracture is an acceptable treatment option for elite skiers who have a full thickness articular cartilage lesion of the knee.
Acknowledgments This research was performed at the Steadman Philippon Research Institute, Vail, CO. The institution received financial support not related to this research from the following: Arthrex, Inc., Opedix, Ossur Americas, Siemens Medical Solutions USA, and Smith & Nephew Endoscopy.
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17
18
19
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References
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1 Gobbi A, Karnatzikos G, Kumar A. Long-term results after micro-
fracture treatment for full-thickness knee chondral lesions in athletes. Knee Surg Sports Traumatol Arthrosc 2013; September 20 (Epub ahead of print) 2 Gobbi A, Nunag P, 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(3): 213–221 3 Mithoefer K, Williams RJ III, Warren RF, Wickiewicz TL, Marx RG. High-impact athletics after knee articular cartilage repair: a prospective evaluation of the microfracture technique. Am J Sports Med 2006;34(9):1413–1418 4 Steadman JR, Miller BS, Karas SG, Schlegel TF, Briggs KK, Hawkins RJ. The microfracture technique in the treatment of full-thickness The Journal of Knee Surgery
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23 24
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chondral lesions of the knee in National Football League players. J Knee Surg 2003;16(2):83–86 Namdari S, Baldwin K, Anakwenze O, Park MJ, Huffman GR, Sennett BJ. Results and performance after microfracture in National Basketball Association athletes. Am J Sports Med 2009; 37(5):943–948 Cerynik DL, Lewullis GE, Joves BC, Palmer MP, Tom JA. Outcomes of microfracture in professional basketball players. Knee Surg Sports Traumatol Arthrosc 2009;17(9):1135–1139 Riyami M, Rolf C. Evaluation of microfracture of traumatic chondral injuries to the knee in professional football and rugby players. J Orthop Surg 2009;4:13 Blevins FT, Steadman JR, Rodrigo JJ, Silliman J. Treatment of articular cartilage defects in athletes: an analysis of functional outcome and lesion appearance. Orthopedics 1998;21(7): 761–767, discussion 767–768 Harris JD, Brophy RH, Siston RA, Flanigan DC. Treatment of chondral defects in the athlete’s knee. Arthroscopy 2010;26(6): 841–852 Gelber AC, Hochberg MC, Mead LA, Wang NY, Wigley FM, Klag MJ. Joint injury in young adults and risk for subsequent knee and hip osteoarthritis. Ann Intern Med 2000;133(5):321–328 Alford JW, Cole BJ. Cartilage restoration, part 1: basic science, historical perspective, patient evaluation, and treatment options. Am J Sports Med 2005;33(2):295–306 Brittberg M, Lindahl A, Nilsson A, Ohlsson C, Isaksson O, Peterson L. Treatment of deep cartilage defects in the knee with autologous chondrocyte transplantation. N Engl J Med 1994;331(14):889–895 Steadman JR, Rodkey WG, Rodrigo JJ. Microfracture: surgical technique and rehabilitation to treat chondral defects. Clin Orthop Relat Res 2001;(391, Suppl):S362–S369 Steadman JR, Briggs KK, Rodrigo JJ, Kocher MS, Gill TJ, Rodkey WG. Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up. Arthroscopy 2003;19(5):477–484 Steadman JR, Rodkey WG, Singleton SB, Briggs KK. Microfracture technique for full-thickness chondral defects: technique and clinical results. Oper Tech Orthop 1997;7:300–304 Harwin SF. Arthroscopic debridement for osteoarthritis of the knee: predictors of patient satisfaction. Arthroscopy 1999;15(2): 142–146 Hangody L, Kish G, Kárpáti Z, Szerb I, Udvarhelyi I. Arthroscopic autogenous osteochondral mosaicplasty for the treatment of femoral condylar articular defects. A preliminary report. Knee Surg Sports Traumatol Arthrosc 1997;5(4):262–267 Asik M, Ciftci F, Sen C, Erdil M, Atalar A. The microfracture technique for the treatment of full-thickness articular cartilage lesions of the knee: midterm results. Arthroscopy 2008;24(11): 1214–1220 Lysholm J, Gillquist J. Evaluation of knee ligament surgery results with special emphasis on use of a scoring scale. Am J Sports Med 1982;10(3):150–154 Tegner Y, Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 1985;(198):43–49 Steadman JR. Microfracture. In: Feagin JA, Steadman JR, eds. The Crucial Principles in Care of the Knee. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:129–151 Hurst JM, Steadman JR, O’Brien L, Rodkey WG, Briggs KK. Rehabilitation following microfracture for chondral injury in the knee. Clin Sports Med 2010;29(2):257–265, viii Higgins RW, Steadman JR. Anterior cruciate ligament repairs in world class skiers. Am J Sports Med 1987;15(5):439–447 International Ski Federation. Cup Standings. Available at: http:// www.fis-ski.com/uk/disciplines/alpine-skiing/cupstandings.html. Accessed August 1, 2013 Kreuz PC, Erggelet C, Steinwachs MR, et al. Is microfracture of chondral defects in the knee associated with different results in patients aged 40 years or younger? Arthroscopy 2006;22(11): 1180–1186
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Outcomes after Knee Microfracture of Chondral Defects in Alpine Ski Racers J. Richard Steadman, MD1 Chad M. Hanson, MD2 Evan W. James, BS1 Alyson Guillet, MD1 1 Center for Outcomes-Based Orthopaedic Research (COOR),
Steadman Philippon Research Institute, Vail, Colorado 2 Desert Orthopaedic Center, Henderson, Nevada
Karen K. Briggs, MPH1
Lauren M. Matheny, BA1
Address for correspondence J. Richard Steadman, MD, Center for Outcomes-Based Orthopaedic Research, Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657 (e-mail: [email protected]).
Abstract
Keywords
► ► ► ►
articular cartilage microfracture alpine ski racers outcomes
Articular cartilage defects of the knee have been shown to cause pain, swelling, decreased function, and suboptimal athletic performance. Treatment of elite-level athletes presenting with full-thickness chondral defects of the knee continues to be a challenge for orthopedic surgeons. The purpose of this study was to document outcomes in elite professional alpine ski racers after microfracture surgery. This study was approved by an institutional review board. All patients who competed in professional ski races recognized by International Ski Federation and had a full-thickness knee articular cartilage defect, treated with microfracture, by a single surgeon, were included in the study. All data were collected prospectively. At minimum 2 years following microfracture, all patients completed a questionnaire, including Lysholm score, Tegner activity scale, and patient satisfaction with outcome. Minimum 2-year follow-up was available for 18 of 20 skiers (90%) at an average follow-up of 77 months (range, 24–255 months). Size of knee articular cartilage defect was larger in males (195 mm2) compared with females (155 mm2); however, this difference was not statistically significant (p > 0.05). Median postoperative Tegner activity scale was 10 (range, 4– 10). Mean postoperative Lysholm score was 86 (range, 41–100). Median postoperative patient satisfaction score was 10 (range, 9–10). Out of the 20 skiers, 19 (95%) returned to competitive skiing. The age of the skier who did not return was 28 years. The average time from surgery to return to competition was 13.4 months (range, 0.5–25.3 months). Average end-of-season overall World Cup ranking was calculated for the nine skiers before and after surgery. Of these nine skiers, six had an improved average overall World Cup ranking after microfracture. In this study, patient satisfaction with outcome and function were high following microfracture of full-thickness chondral lesions of the knee. Nearly all skiers returned to full competition. Microfracture is an acceptable treatment option for elite skiers who have full thickness articular cartilage lesions of the knee.
Articular cartilage defects of the knee have been shown to cause pain, swelling, decreased function, and suboptimal athletic performance during sport participation.1–3 The treatment of elite-level athletes presenting with full-thickness chondral de-
fects of the knee continues to be a challenge for orthopedic surgeons.1–9 If left untreated, these defects rarely heal spontaneously due to the avascular nature of articular cartilage, whether the lesion is acute, chronic, or degenerative.1–7
received December 30, 2013 accepted March 6, 2014 published online May 22, 2014
Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.
DOI http://dx.doi.org/ 10.1055/s-0034-1376330. ISSN 1538-8506.
Downloaded by: Rutgers University. Copyrighted material.
J Knee Surg 2014;27:407–410.
Microfracture in Alpine Ski Racers
Steadman et al.
In addition, these defects may predispose individuals to the development of knee osteoarthritis; which is why early intervention is recommended to mitigate this risk.10,11 Many different surgical treatments have been described for the treatment of full-thickness articular cartilage defects of the knee, including arthroscopic debridement, mosaicplasty, autologous chondrocyte implantation, and microfracture.12–17 The advantages of microfracture include the simplicity of the surgical technique, relatively low complication rates, and the low cost of the procedure.1,2 Good to excellent outcomes following microfracture for the treatment of articular cartilage defects have been reported, with patients returning to their desired activity level.1,2,14,18 Microfracture outcomes in the elite athlete have also been published for various sports, including professional football and basketball.3–6,8 However, documented outcomes following microfracture of the knee in the professional ski racer are limited. The purpose of this study was to document outcomes in elite professional alpine ski racers after microfracture surgery and a structured rehabilitation protocol.
Methods Patient Selection This study was approved by an institutional review board. Between 1986 and 2008, all patients who competed in professional ski races recognized by the International Ski Federation (FIS) and had a full-thickness articular cartilage defect of the knee, confirmed during arthroscopy, that was treated with microfracture, by a single surgeon, were identified. Patients were included in the study based on active ski competition immediately before surgery. Patients were excluded from this study if they were not at least 2 years out from surgery or had severe knee malalignment. In addition, patients who retired from professional skiing before surgery were also excluded from this study. Demographic data, detailed surgical findings, intraoperative data, and subjective data were collected prospectively for all patients and stored in a data registry. At a minimum 2 years following index microfracture surgery, all patients were asked to complete a questionnaire that included the Lysholm19 score to document function, the Tegner20 activity scale to document activity level, and a patient satisfaction with outcome question. Satisfaction was measured on a 10-point scale, with 10 equal to being very satisfied and 1 equal to being very unsatisfied with outcome. Return to sport was documented using ski race results published by FIS19 and was defined as participation in a ski race at any time after surgery that was recognized by the FIS Professional races which included the World Cup, European Cup, Nor-Am Cup, and Olympics. Statistical analysis was performed using SPSS for Windows (version 11.0, SPSS Inc., Chicago, IL).
Operative Technique All patients underwent knee arthroscopy with microfracture using the surgical technique as described by Steadman et al.13,15 Intra-articular evaluation of the articular cartilage defect was performed. Once the lesion was confirmed to be The Journal of Knee Surgery
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No. 5/2014
full thickness, the defect was prepared and measured. Next, multiple 3 to 4 mm deep microfracture holes were placed in a carefully spaced manner so as to be in close proximity to one another, without breaking into adjacent holes. Before the completion of the case, the arthroscopy pump pressure was reduced to ensure bleeding had occurred at the microfracture site. No drains were left within the joint. Over the subsequent weeks, all patients underwent a standardized postoperative rehabilitation program as described by Steadman et al.21,22 The rehabilitation of the tibiofemoral joint includes the use of a continuous passive motion machine for the first 6 weeks. Crutch-assisted weightbearing is prescribed for 8 weeks.13 As necessary, the program was supplemented to accommodate rehabilitation of concomitant ligamentous reconstructions completed at the time of microfracture.23
Rehabilitation Protocol for Patients with Patellofemoral Lesions All patients treated by microfracture for patellofemoral lesions must use a brace set at 0 to 20 degrees for at least 8 weeks. The brace limits compression of regenerating surfaces of the trochlea and patella. Passive motion with the brace removed is allowed, but otherwise, the brace must be worn at all times. Patients are placed into a continuous passive motion machine immediately after surgery. Cold therapy is also prescribed. Joint angles are carefully observed during arthroscopy to determine where the defect comes into contact with the patellar facet or the trochlear groove. We avoid these areas during strength training for approximately 4 months. This avoidance allows for training in the 0 to 20 degrees range immediately postoperatively because there is a minimal compression of these chondral surfaces with such limited motion. Patients are allowed weightbearing as tolerated in their brace 2 weeks after surgery. It is essential for patients to use a brace that prevents placing excessive shear force on the maturing marrow clot in the early postoperative period. We routinely lock the brace between 0 and 20 degrees range of motion to prevent flexion past the point where the median ridge of the patella engages the trochlear groove. After 8 weeks, the knee brace is gradually opened. When the brace is discontinued, patients are allowed to advance their training progressively. Stationary biking is allowed 2 weeks postoperatively, with increased resistance added at 8 weeks after microfracture. Starting 12 weeks after microfracture, the exercise program is the same one used for femorotibial lesions.21,22
Results A total of 20 patients (16 females and 4 males) with a mean age of 23 years (range, 15–29 years) met the inclusion criteria and were included in this study. Three patients had microfracture on both knees. No complications attributed to surgery were identified. One patient underwent microfracture of a bipolar or “kissing” lesion. The majority of lesions treated (62%) involved the lateral femoral condyle. The distribution of location of cartilage defects are listed in ►Table 1. Mean lesion size was 155 mm2 (range, 5–450 mm2).
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Table 1 Traumatic chondral defects in professional alpine ski racers Number of knees (n)
Patella
2
Lateral femoral condyle
13
Medial femoral condyle
3
Trochlear groove
1
Medial tibial plateau
0
Lateral tibial plateau
0
Lateral tibial plateau and lateral femoral condyle
1
Medial femoral condyle, patella, and trochlear groove
1
Outcome Scores Minimum 2-year follow-up was available for 18 of 20 skiers (90%) at an average follow-up of 6.4 years (range, 2.0–21.3 years). Median postoperative Tegner activity scale was 10 (range, 4–10). Mean postoperative Lysholm score was 86 (range, 41–100). Median postoperative patient satisfaction with outcome score was 10 (range, 9–10). Females had an average postoperative Lysholm score of 88 and males had an average postoperative Lysholm score of 91. Age was not associated with outcome scores, and there was no difference in outcome scores based on gender (p > 0.05). The size of the knee articular cartilage defect was larger in males (195 mm2) compared with females (155 mm2); however, this difference was not statistically significant (p > 0.05).
Return to Competition and Level of Performance Out of the 20 skiers, 19 (95%) returned to competitive skiing. The age of the skier who did not return was 28 years. The average time from surgery to return to competition was 13.4 months (range, 0.5–25.3 months). Males returned to skiing competitively in an average of 13.0 months and females returned in an average of 14.5 months. The 19 skiers who returned to competition all competed in FIS endorsed races. Athlete accomplishments after return to play included podium finishes in the European Cup, National Championships, World Cup, Nor Am Cup, and the Olympics. Data for overall World Cup rankings pre-microfracture and post-microfracture were available for nine skiers in the FIS’s database.24 Average end-of-season overall World Cup ranking was calculated for the nine skiers before and after surgery (►Fig. 1).24 Of these nine skiers, six had an improved average overall World Cup ranking after microfracture.
Discussion In this study, 19 of the 20 competitive skiers (95%) returned to competitive skiing following microfracture surgery for the treatment of a full-thickness articular cartilage defect. Patient satisfaction with outcome was excellent and knee function was high. Previous studies have reported conflicting results documenting return to sport after microfracture surgery, ranging from 44 to
Fig. 1 Average World Cup ranking pre- and post-microfracture for five athletes who we were able to extract rankings before and after surgery.
100% of athletes returning to sport competition.2–8 In a study that documented return to play following microfracture in professional football players, 76% of players returned to sport. Patients averaged playing an additional 4.6 seasons (56 more games) following microfracture surgery.4 In a similar study of professional basketball players, 19 of 24 players (79%) returned to sport after a mean of 7.5 months following microfracture surgery, which is similar to the results of our study.6 Previous studies have also shown that younger age is associated with better outcomes following microfracture.13,14,18,25 Mithoefer et al3 documented outcomes following microfracture of one or both of the femoral condyles, in athletes who participated in high-impact, pivoting sports. At a mean of 54 months, approximately 66% of patients, with a mean age of 38 years, reported good to excellent outcomes following microfracture. However, only 44% of their cohort returned to high-impact sports. Of this subset who returned to play, 57% reported performing at their preinjury level. Finally, 47% of the athletes reported a decline in function following their initial improvement. This study found that younger age and smaller lesion size was associated with better outcomes and microfracture was found to be an effective primary treatment of articular cartilage defects in the athletic knee.3 It is important to note that in this study, patients were non-weightbearing for 6 weeks instead of 8 weeks,21 which may explain the lower return to play percentage. Kreuz et al also studied the effect of age in 85 patients treated with microfracture and reported significantly better results in the modified Cincinnati knee and International Cartilage Repair Society scores in patients 40 years of age or younger.25 We observed similar improvements in function and satisfaction in our patient population, which, by nature of the sport, consists of relatively young athletes. Our study had a mean age of 23.1 years which may have contributed to the high rate of return to competition and favorable outcomes documented in this study. In our study, six of the nine skiers with overall World Cup rankings reported in the FIS database improved their average ranking after surgery, indicating that some ski racers not only returned to competition but excelled, and some athletes excelled beyond presurgery levels of performance. Various studies have documented good to excellent outcomes The Journal of Knee Surgery
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Microfracture in Alpine Ski Racers
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following knee microfracture; however, few studies have documented outcomes and return to competition in highlevel athletes, especially in this unique patient population. It is unclear why patients in this study had a higher percentage of athletes return to competitive sport than in several previous studies. Additional research is necessary to determine long-term outcomes in these elite athletes as they continue to progress in age. However, other studies did not use the same 8 weeks non-weightbearing guideline and other aspects of the rehabilitation protocol.
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Limitations Our study has several limitations. This study was conducted at a referral clinic and is based on an elite level of athlete, and therefore may not be representative of the general patient population. This study was retrospective in nature; however, all data were collected prospectively. This study was relatively small due to the nature of the patients being studied. With data from the FIS, it was possible to document return to sport; however, it was difficult to compare best finishes at professional races pre- and postsurgery due to unreported results data in some cases, as well as intangible confounding variables in race location, conditions, and the competitiveness of the field across multiple years of competition. There is the possibility of gender bias, but this would be difficult to control in future studies due to the highly specific nature of the study population.
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Conclusion In this study, patient satisfaction with outcome and function were high following microfracture of a full-thickness chondral lesion of the knee with structured rehabilitation. In addition, nearly all skiers returned to full competition. Microfracture is an acceptable treatment option for elite skiers who have a full thickness articular cartilage lesion of the knee.
Acknowledgments This research was performed at the Steadman Philippon Research Institute, Vail, CO. The institution received financial support not related to this research from the following: Arthrex, Inc., Opedix, Ossur Americas, Siemens Medical Solutions USA, and Smith & Nephew Endoscopy.
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References
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