1. THE GENDER ISSUES FOR THE TOTAL KNEE ARTHROPLASTY
中華民國關節重建醫學會98年度春季研討會
台北醫學大學萬芳醫學中心
何為斌 醫師
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2. Are There Gender-Specific Knee Anatomic Differences?
Femurs : Men > women (A-P height, M-L width, height of the lateral and medial condyles).
For the same anterior-posterior dimension of the distal femur, women have a narrower medial-lateral width.
Trochlear groove rotated externally relative to the epicondylar axis in females and somewhat internally in males.
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3. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
TAIPEI MEDICAL UNIVERSITY‧WANFANG MEDICAL CENTER 骨科
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4. Are There Gender-Specific Knee Anatomic Differences?
Patellofemoral joint : Q angle,F>M, same height have similar Q angles, taller people have slightly lower Q angles
Length of the patellar tendon / the greatest diagonal length of the patella (patellar alta) : F > M, more negative congruence angle
Size of the patella : M>F
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5. CORR 1996;331:35-46, Poilvache PL et al
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6. Are There Gender-Specific Knee Anatomic Differences?
Patellofemoral joint biomechanics : cadaveric specimens, knee flexion angles greater than 30°,contact area : M >F
Mean patellofemoral contact pressures and peak pressures : F>M at 0°, 30° and 60° of knee flexion, statistically significantly
Difference in soft-tissue characteristics, physical activities, and psychological makeup
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7. Results : angles of 269 men and 257 women Supine Standing
normal, mean quadriceps angles (Q angles) for college-aged men and women, measured in the supine and the standing positions.
Results : angles of 269 men and 257 women
Supine Standing
Male
Female
All of these differences were statistically significant.
Woodland LH - Am J Sports Med - 01-MAR-1992; 20(2):
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8. Morphometrical measurement of Resected Femoral Section in Taiwan
Lat condyle Female = 62.1 ± 4.1 mm
Male = 70.7 ± 4.2 mm
Post intercondyle Female = 67.5 ± 3.1 mm
Male = 77.9 ± 3.3 mm
AP:ML Female = 0.907
Male = 0.919
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9. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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10. The femoral M/L measurements versus A/P measurements (mm) for 337 knees
Kirby Hitt,et al
J. Bone Joint Surg. Am. 85: , 2003.
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11. AP/ML measurement of traditional prosthesis in female and male
209 Female Male
Kirby Hitt,et al
J. Bone Joint Surg. Am. 85: , 2003.
J of Arthroplasty Vol. 22,Oct, 2007 pp: 27-31
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12. The femoral aspect ratio ( ML/AP× 100 ) versus the anterior-posterior (A/P) measurements (mm)
209 Female Male
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13. The tibial M/L measurements versus A/P (mm) for 337 knees.
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14. The tibial aspect ratio versus the anterior-
posterior (A/P) measurements (mm)
209 Female Male
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15. Gender specific knee, women knee prosthesis
3 Distinct Differences
thinner profile than traditional knee replacements,
2. allows for more natural movement of the kneecap,
3. shape specially contoured for women.
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16. 1. Thinner Profile
The bone in the front of a woman's knee is typically less prominent than in a man's.
2. More Natural Movement
Women have a distinct shape that frequently results in a different angle between the hip and the knee when compared to men.
3. Contoured Shape
The contoured shape is more closely match the narrower anatomy of a woman's knee.
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17. 1. Thinner Profile. 2. More Natural Movement 3. Contoured Shape
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18. Compare traditional and gender specific prosthesis
Traditional prosthesis
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19. Overlay of Stryker Triathlon size 3 and Zimmer Gender Solutions size E templates for both AP and ML sizing (both use 115% magnification).
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20. After the Gender Solutions knee was marketed :
Is this just a marketing gimmick for a company to get more financial gain?
The competition among orthopedic companies is so great that those lacking this innovation must find ways to mitigate their expected loss of market share.
Some companies have said that it simply doesn't matter,
their current prosthesis was designed "with women in mind“, their system already deals with this issue by adding half sizes to their current inventory
This is about shape, not size. Women are not simply little men.
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21. Zimmer LPS-Flex Gender
Size C D E F G AP
53.3
57.5
61.2
65.3
70.4 ML 58
61.4
64.7
68.1
71.5
Ant flange
Med / Lat
5.0/5.1
5.1/5.3
4.9/5.0
6.0/6.4
Q = 10 °
Zimmer LPS-Flex PS
size C D E F G AP
54.4
58.6
62.5
66.5
71.5 ML
60.0
64.0
68.0
72.0
76.5
Ant flange
Med/ Lat
5.2/6.2
5.9/6.4
5.7/6.2
6.0/6.4
6.6/7.3
Q = 7°
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22. Gender Knee 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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23. Traditional KNEE 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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24. Gender knee Traditional Knee
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25. Gender knee Traditional knee
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26. Does this gender-specific knee mean that surgeons have been placing the "wrong" knee in women for the past 30 years? No,
When your new car came out with power steering, airbags, a computerized braking system, or blowout-proof tires, did you presume that the previous car was "the wrong one?"
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27. National Institutes of Health (NIH) : Consensus Conference on Total Knee Replacement in December 2003.
Agency for Healthcare Research and Quality (AHRQ) : systematic review of the literature published between 1995 and April 2003.
The AHRQ concluded, "There is no evidence that age, gender, or obesity is a strong predictor of functional outcomes."
AAOS Systematic review of literature published between April 1, 2003, and November 2006 in PubMed, and used article inclusion/exclusion criteria nearly identical to those in the AHRQ report
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28. Question #1: Do women have higher failure rates than men after traditional knee replacement surgery?
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29. Including / excluding criteria
1. Article must be a full report and not a meeting abstract. Meeting abstracts do not contain sufficient information to allow for complete evaluation of study design and conduct. Further, many abstracts are never published as full reports.
2. Article must be published in English. Translation costs are prohibitive.
3. Study must be of humans.
4. Article must present results in quantitative fashion.
5. Studies of unicondylar knee replacements are excluded.
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30. 66 / 1,777 articles. potentially meeting inclusion criteria, and 24 were ultimately included.
The data published subsequent to the AHRQ report do not consistently show differences between men and women in most of the outcomes of tricompartmental total knee replacement surgery.
No significant difference : revision rates, range of motion, and scores on several outcomes instruments
Possible exceptions : women may have a longer length of stay and lower death rates than men
None of the studies included were specifically designed to evaluate gender differences, and they were not of high quality
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31. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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32. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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33. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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34. 臺北醫學大學‧台北市立萬芳醫院 骨科 Orthopaedic Department
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35. Question #2: Does gender-specific knee replacement increase the rates of successful knee replacement surgery in women?
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36. Additional Criteria for Question #2:
1. Include any study of any design that examined 10 or more knees. (This criterion is less restrictive than the analogous criterion for Question 1.)
2. No restriction on outcome. May be either intermediate or patient-oriented.   
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37. These searches did not identify any clinical studies that directly addressed this question.
"There is no evidence that age, gender, or obesity is a strong predictor of functional outcomes."
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38. AAOS :
This is not an official AAOS position on gender- specific knees, does not make recommendations for or against the use of gender-specific knee replacements
Patient care and treatment should always be based on a clinician’s independent medical judgment given the individual clinical circumstances.
AAOS would like to have feedback from its members on this Technology Overview
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39. The clinical effect of gender on outcome of total knee arthroplasty.
7326 primary AGC (Biomet,) CR TKAs between 1987 to
59.5% were performed on women.
Knee Society knee score, function scores, pain scores, walking ability, stair-climbing ability, flexion, and implant survivorship based on sex.
Male and female : equal 1. pain relief and walking improvements (P < .32) 2. Implant survival = 98% at 15 years (P = .4684).
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Ritter MA, et al. J Arthroplasty Apr;23(3):331-6              

40. Male : Stair and function score improvements were greater (P = .002).
Female : lower overall preoperative clinical scores for all parameters (P < .01).
Female : greater improvement in Knee Society knee score and flexion (P = .006)
Male : Stair and function score improvements were greater (P = .002).
Conclusion : improvement after TKA is similar for men and women, with few clinically significant differences. Sex-specific implants would appear to offer no clinical advantage.
The clinical effect of gender on outcome of total knee arthroplasty. Ritter MA, et al. J Arthroplasty Apr;23(3):331-6 
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41. Gender-specific Total Knee Replacement : Prospectively Collected Clinical Outcomes
3817 patients, 5279 primary TKAs (3100 female, 2179 male) with a minimum of 2 years follow-up
Preoperative, latest, and change WOMAC, SF-12, KSCRS were compared.
men had higher raw scores preoperatively
women had greater improvement in all WOMAC including pain (29.87 versus 27.3), joint stiffness (26.78 versus ), function (27.21 versus 23.09), and total scores (28.35 versus 25.09).
There were no gender differences in improvements of the SF-12 physical scores.
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Macdonald SJ et al. Clin Orthop Relat Res Sep

42. Revision rates were 10.2% for men and 8% for women.
Men had greater improvement in Knee Society function (22.1 versus 18.63) and total scores (70.01 versus ), but not the Knee Society knee score ( versus 46.64).
Revision rates were 10.2% for men and 8% for women.
Women demonstrated greater implant survivorship, greater improvement in WOMAC scores, equal improvements in SF-12 scores, and less improvement in only the Knee Society function and total scores.
Conclusion : data refute that women had inferior clinical outcome when using standard TKA components.
Gender-specific Total Knee Replacement: Prospectively Collected Clinical Outcomes, Macdonald SJ et al Clin Orthop Relat Res Sep.
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43. Gender-specific design in total knee arthroplasty
Rand and Ilstrup reviewed the survivorship of 9200 TKAs
Implant survival rate in women was significantly greater than that of men, both at 5-year (93% vs 89%) and 10- year follow-up (83% vs 76%).
Wright et al : no sex differences in survivorship of 523 TKAs followed up at a minimum of 10 years
Font-Rodriguez et al also found no sex differences in TKAs with follow-up of 7 to 21 years.
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Greene KA. J Arthroplasty Oct;22(7 Suppl 3):27-31 .

44. Gender-specific design in total knee arthroplasty
multiple factors come into play, involving the patient, surgical technique, and implant design.
Conclusion : there is little evidence to suggest that these sex-specific changes will translate into improved outcomes, and further research is obviously needed to assess the impact of sex-specific design changes.
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Greene KA. J Arthroplasty Oct;22(7 Suppl 3):27-31

45. The need for gender-specific prostheses in TKA: does size make a difference?
Aging boomers and younger patients requiring total knee arthroplasty demand and/or expect better function, improved durability, and a quicker recovery.
In response to this demand, surgeons are modifying surgical techniques, and industry is examining implant design.
CONCLUSION : development of separate systems for men and women may prove to be unnecessary.
Barrett WP. Orthopedics Sep;29(9 Suppl):S53-5.
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46. Early experience with a new total knee implant: maximizing range of motion and function with gender-specific sizing
668 consecutive TKAs using Triathlon gender-specific prosthesis,
2 yeas f/u
Early outcomes: mean Knee Society pain and function scores, preoperative total score of 78 to a postoperative of 182.
Harwin SF, Greene KA, Hitt K. Surg Technol Int. 2007;16:
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47. Early experience with a new total knee implant: maximizing range of motion and function with gender-specific sizing
Mean preoperative flexion of 102 degrees, post-op 116 degrees at 6 weeks, 124 degrees at 3 months, and 128 degrees at 1 year.
Whereas long-term results cannot be predicted, no early failures or serious complications were encountered.
Conclusion : Needs long-term outcome of this cohort study
Harwin SF, Greene KA, Hitt K. Surg Technol Int. 2007;16:
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48. One of the best things about the gender-specific knee prosthesis initiative is that it heralds a new era of increased sophistication, not merely putting in generic mechanical devices but coming even closer to matching the more complicated anatomic variations that the spectrum of humanity presents to us for treatment.
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Robert E Booth Jr. Orthopedics. Sep Vol. 29, Iss. 9; pg. 768,

49. Conclusion I
Sex-specific implants would appear to offer no clinical advantage,….
refute the hypothesis of inferior clinical outcome for women following total knee arthroplasty when using standard components,…..
little evidence…. will translate into improved outcomes
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50. Conclusion II
AAOS : "There is no evidence that age, gender, or obesity is a strong predictor of functional outcomes.“
AAOS does not make recommendations for or against the use of gender-specific knee replacements
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51. Conclusion III
To resist that challenge would be to hold back the tide of improvement.
It is our privilege and our mandate now to go beyond.
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52. THANK YOU VERY MUCH FOR YOUR ATTENTION
謝謝聆聽
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