A C Keays

University of the Sunshine Coast, Gold Coast, Queensland, Australia

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Publications (9)17.83 Total impact

  • 01/2011;
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    ABSTRACT: The incidence of osteoarthritis after anterior cruciate ligament reconstruction is disturbingly high, with reports of nearly 50% of patients developing mild to moderate osteoarthritis 6 years after surgery. Few studies have assessed the factors involved in the development of osteoarthritis. The following 10 factors will be found to be predictive of osteoarthritis: meniscectomy, chondral damage, patellar tendon grafting, age at surgery, time delay between injury and surgery, type and intensity of postsurgery sport, quadriceps strength, hamstring strength, quadriceps-to-hamstring strength ratio, and residual joint laxity. Cohort study (prognosis); Level of evidence, 1. Fifty-six subjects with anterior cruciate ligament reconstruction were followed for 6 years after surgery. Assessment included KT-1000 arthrometer testing, isokinetic strength testing, a return-to-sport questionnaire, and a radiograph assessment. A discriminant analysis was performed to assess which of the 10 factors could discriminate between those patients who developed tibiofemoral and patellofemoral osteoarthritis and those who did not. Five factors were found to be predictive of tibiofemoral osteoarthritis. Meniscectomy (r = .72) and chondral damage (r = .41) were the strongest discriminators, followed by patellar tendon grafting (r = .37) (chi(2) [7, n = 56] = 25.48; P = .001). Weak quadriceps (r = .39) and low quadriceps-to-hamstring strength ratios (r = .6) were very close discriminators (chi(2) [8, n = 42] = 15.02; P = .059). For patellofemoral osteoarthritis, meniscectomy (r = .45), chondral damage (r = .75), and age at surgery (r = .65) were predictors or close predictors (chi(2) [7, n = 54] = 13.30; P = .065). As not all 10 factors studied were predictive of osteoarthritis, the hypothesis was only partially proven. Preventing further meniscal and chondral damage in patients with anterior cruciate ligament deficiency is critical. Grafting using the hamstring tendons and restoration of quadriceps-to-hamstring strength balance are associated with less osteoarthritis.
    The American journal of sports medicine 03/2010; 38(3):455-63. · 3.61 Impact Factor
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    ABSTRACT: The choice of graft material for anterior cruciate ligament reconstruction remains controversial. Despite the need for well-controlled, long-term outcome studies comparing patellar tendon with hamstring grafting, few studies have followed results for more than 5 years. Graft source will not affect outcome 6 years after reconstruction. Cohort study; Level of evidence, 2. Sixty-two patients with anterior cruciate ligament reconstruction and 18 uninjured control subjects were studied over 6 years. Thirty-one patients received patellar tendon grafts, and 31 received hamstring tendon grafts. Assessment included knee joint stability, range of motion, muscle strength, subjective function, objective function (running, sidestepping, carioca, and hop tests), and joint degeneration. Clinical stability was restored to all patients other than to the 2 hamstring graft recipients who suffered reinjuries. The KT-1000 arthrometer side-to-side differences were similar in the patellar tendon (1.9 mm) and hamstring tendon (2.0 mm) groups but were significantly greater than that of uninjured control subjects (P < .001). There were no significant strength differences between surgical and control groups, although a 6% quadriceps deficit existed after patellar tendon grafting. In the more demanding functional tests (hop and triple-hop indices and carioca), the hamstring graft recipients performed similarly to the control group, whereas a significant difference (P < .05) existed between the patellar tendon graft and the control group. The incidence of early tibiofemoral osteoarthritis was significantly greater after reconstruction using patellar tendon (62%) than after hamstring tendon grafting (33%; P = .002). Six-year outcomes were very satisfactory irrespective of graft source. However, reconstruction using the hamstring tendons resulted in improved functional performance and a lower incidence of osteoarthritis.
    The American Journal of Sports Medicine 06/2007; 35(5):729-39. · 4.44 Impact Factor
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    ABSTRACT: Functional stability of the knee is dependent on an intact ligamentous system and the timely and efficient contraction of supporting musculature. The aim of this study was to assess the relationship between muscle strength and functional stability in 31 patients pre- and post-operatively, following a unilateral anterior cruciate ligament rupture. All subjects underwent reconstructive surgery using semitendonosis and gracilis tendons. Isokinetic strength assessment of quadriceps and hamstring muscles was performed at a rate of movement of 60 degrees /s and 120 degrees /s. Functional stability was determined by performance during five functional stability tests that included the shuttle run, side step, carioca, single and triple hop tests. Pearson's correlation coefficient statistics were applied to pre-operative and post-operative data respectively. These analyses demonstrated a significant positive correlation between quadriceps strength indices at both testing speeds and the two hop tests pre-operatively (p's<0.007) and between quadriceps strength indices at both speeds and all five functional tests post-operatively (p's<0.01). Assessed using Steiger's formula, there was a significant increase in the correlation between quadriceps strength indices and three functional tests post-operatively compared to pre-operatively (p<0.05). No significant correlation between hamstring strength indices and functional scores existed pre- or post-operatively. This study has shown a significant correlation exists between quadriceps strength indices and functional stability both before and after surgery, this relationship does not reach significance between hamstring strength indices and functional stability.
    Journal of Orthopaedic Research 03/2003; 21(2):231-7. · 2.88 Impact Factor
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    ABSTRACT: Anticoagulation used for thromboembolic prophylaxis following total knee arthroplasty (TKA) could interfere with movement. This study compares the effect of 2 anticoagulants, enoxaparin and aspirin, on restoration of range of motion (ROM) after TKA. Two groups of 75 consecutive patients, matched for age, arthritic severity, and preoperative ROM, underwent TKA. Flexion and extension milestone measures were recorded daily. Results show a highly statistically significant difference (P<.001) between the 2 groups when comparing the days on which these milestones were achieved. Group 1 (enoxaparin) reached 90 degrees, 100 degrees and 110 degrees of flexion in 8.4, 10.4, and 12.4 days, respectively. Group 2 (aspirin) reached the same goals in 6.8, 8.5, and 10.6 days, respectively. At 15 months after surgery, no statistically significant difference in flexion was seen between the groups (122 degrees vs 121 degrees ). Enoxaparin delayed the return of early but not long-term flexion after TKA.
    The Journal of Arthroplasty 02/2003; 18(2):180-5. · 2.11 Impact Factor
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    ABSTRACT: This study assessed the quadriceps and hamstring strength before and 6 months after anterior cruciate ligament (ACL) reconstructive surgery using the hamstrings and related the findings to functional performance. Six months after surgery is a critical time for assessment as this is when players are returning to sport. Maximum isokinetic strength of 31 patients with complete unilateral ACL ruptures was measured at speeds of 60 degrees and 120 degrees per second. Functional assessment included the single hop, the triple hop, the shuttle run, side-step and carioca tests. All patients underwent a controlled quadriceps emphasized home-based physiotherapy program both before and after surgery. Results show that before surgery there was a 7.3% quadriceps strength deficit at 60 degrees per second compared to the uninjured leg but no hamstring strength deficit. After surgery there was a statistically significant but relatively small loss of muscle strength. The quadriceps strength deficit had increased to 12% and there was a 10% hamstring deficit. Post-operatively there was an 11% and 6.3% improvement in the hop tests, a 9% (P < 0.01) improvement in the shuttle run, a 15% (P < 0.001) improvement in the side step and a 24% (P < 0.001) improvement in the carioca tests (P < 0.001) despite the loss of muscle strength.
    The Knee 11/2001; 8(3):229-34. · 2.01 Impact Factor
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    ABSTRACT: Rehabilitation of patients with anterior cruciate ligament injury is a topic of interest among clinicians. Although numerous studies report the deficits after anterior cruciate ligament reconstruction, there are no data available on the changes in strength and functional performance before and 6 months after reconstruction surgery. This is when most patients are returning to sports activities. In the current study 31 patients with complete unilateral anterior cruciate ligament ruptures followed a controlled rehabilitation program emphasizing early range of motion after surgery and quadriceps strengthening before and after undergoing bone-patellar tendon-bone reconstruction. Strength of the hamstrings and quadriceps and five functional activities were assessed at 1 week before and 6 months after surgery. Preoperative strength assessments using a Cybex II dynamometer showed a 12% quadriceps deficit at 60 degrees per second and 9% deficit at 120 degrees per second with no hamstring deficit in the injured leg compared with the uninjured leg. Despite intensive quadriceps training, the postoperative quadriceps deficit increased to 28% at 60 degrees per second and 22% at 120 degrees per second in comparison with the uninjured leg. There was no change in hamstring strength in the injured leg. Most functional measures improved after surgery. The shuttle run improved by 10%, the side step test results improved by 17%, and the carioca test results improved by 23%. No significant difference was found in the results of the hop test. This study highlights the extent of the quadriceps deficits despite functional improvement and the difficulty in restoring quadriceps strength after bone-patellar tendon-bone reconstruction. It also questions the relationship of current functional tests to quadriceps strength and the role of maximum strength testing as a predictor of function and of safe sporting performance.
    Clinical Orthopaedics and Related Research 05/2000; · 2.79 Impact Factor
  • S. Keays, A. C. Keays

Publication Stats

285 Citations
17.83 Total Impact Points

Institutions

  • 2010
    • University of the Sunshine Coast
      • School of Health and Sport Sciences
      Gold Coast, Queensland, Australia
  • 2000–2003
    • University of Queensland 
      • Department of Physiotherapy
      Brisbane, Queensland, Australia