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Predictors of Functional Outcome After Hip and Knee Arthroscopy


1. Preoperative function and gender predict pattern of functional recovery after hip and knee arthroplasty.

J Arthroplasty. 2006 Jun;21(4):559-66.

Kennedy DM, Hanna SE, Stratford PW, Wessel J, Gollish JD.

Gender, preoperative function, and other variables were explored as predictors of recovery after total hip and knee arthroplasty. One hundred fifty-two subjects (63.8 +/- 10.2 years) were repeatedly assessed in the first 4 postoperative months. Average recovery curves for the Western Ontario and McMaster Universities Osteoarthritis Index, 6-minute walk test, and timed up and go test were characterized using hierarchical linear modeling. Recovery predictors were sequentially modeled after validation of the basic developmental models. Gender was a significant predictor (P < or= .003) of physical performance measure scores 1 week after surgery. Thereafter, men and women had similar rates of improvement. Preoperative score was a significant predictor (P < or= .001) in all models. Patients’ and surgeons’ expectations of outcome need to take preoperative function into account.

2. Determinants of the subjective functional outcome of total joint arthroplasty.

Arch Gerontol Geriatr. 2005 Sep-Oct;41(2):169-76.

Caracciolo B, Giaquinto S.

The aim of the study is three-fold: (i) to analyze association between early subjective functional outcome of total joint arthroplasty (TJA) and patient-related risk factors; (ii) to evaluate the six-month subjective functional outcome of TJA as compared with subjective functional status of non-operated outpatients; (iii) to evaluate TJA self-perceived amelioration rates compared to the status of an age-matched sample from a general medical practice. A prospective consecutive study was performed upon 100 elderly inpatients with recent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) for osteoarthritis. Interviews on preoperative status and short-term outcome were performed at admission and six months after surgical intervention with Western Ontario and MacMasters Universities Osteoarthritis Index (WOMAC). One hundred aged-matched consecutive outpatients were screened for osteoarthritis and interviewed with the same questionnaire in a single session. Differences between baseline and follow-up scores were evident and statistically significant for both TJA groups, although THA patients showed more improvement. The comparison between TJA patients at baseline and age-matched osteoarthritis outpatients highlighted less impairment among outpatients. The situation reversed six months after the intervention. Objective functional outcome of post-operative rehabilitation has not revealed predictive value for the six-month outcome of TJA in terms of self-perceived functional status. Logistic regression analysis indicated that preoperative status was the only significant predictor of higher WOMAC scores six months after TJA. The survey confirms the early benefit of THA or TKA for osteoarthritis, but a less favorable subjective functional outcome is expected at six months when preoperative subjective functional status is severely compromised.

3. Timing of total joint replacement affects clinical outcomes among patients with osteoarthritis of the hip or knee.

Arthritis Rheum. 2002 Dec;46(12):3327-30.

Fortin PR, Penrod JR, Clarke AE, St-Pierre Y, Joseph L, Bélisle P, Liang MH, Ferland D, Phillips CB, Mahomed N, Tanzer M, Sledge C, Fossel AH, Katz JN.

OBJECTIVE: To determine the predictors of outcome in patients with osteoarthritis 2 years after receiving total hip or knee replacement. METHODS: A prospective cohort study of 222 osteoarthritis patients undergoing total hip or knee replacement in Boston and Montreal was done. Their postoperative outcomes at 6 months were previously reported. This followup reports on the outcomes after 2 years among the 165 patients (74%) who remained. The subjects were divided into 2 groups according to the median value of their preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score. The Short Form 36-item physical function subscale and the WOMAC pain and function subscale scores were collected at baseline and at 3, 6, and 24 months postoperatively. Clinical outcomes were analyzed at 2 years, using descriptive and multiple regression analyses. RESULTS: Improvements in pain and function at 2 years were similar to those observed at 6 months. Those subjects with the worst function and pain at the time of surgery (baseline) had comparatively worse function 2 years after surgery. CONCLUSION: In this comparison, the poor outcomes observed at 6 months following total joint replacement in patients with worse baseline functional status persisted after 2 years. Although there are no validated indications for when a patient should optimally have total joint replacement, these data suggest that timing of surgery may be more important than previously realized and, specifically, that performing surgery earlier in the course of functional decline may be associated with better outcome.

4. Outcomes of total hip and knee replacement: preoperative functional status predicts outcomes at six months after surgery.

Arthritis Rheum. 1999 Aug;42(8):1722-8.

Fortin PR, Clarke AE, Joseph L, Liang MH, Tanzer M, Ferland D, Phillips C, Partridge AJ, Bélisle P, Fossel AH, Mahomed N, Sledge CB, Katz JN.

OBJECTIVE: To determine whether patients with knee or hip osteoarthritis (OA) who have worse physical function preoperatively achieve a postoperative status that is similar to that of patients with better preoperative function. METHODS: This study surveyed an observational cohort of 379 consecutive patients with definite OA who were without other inflammatory joint diseases and were undergoing either total hip or knee replacement in a US (Boston) and a Canadian (Montreal) referral center. Questionnaires on health status (the Short Form 36 and Western Ontario and McMaster Universities Osteoarthritis Index) were administered preoperatively and at 3 and 6 months postoperatively. Physical function and pain due to OA were deemed the most significant outcomes to study. RESULTS: Two hundred twenty-two patients returned their questionnaires. Patients in the 2 centers were comparable in age, sex, time to surgery, and proportion of hip/knee surgery. The Boston group had more education, lower comorbidity, and more cemented knee prostheses. Patients undergoing hip or knee replacement in Montreal had lower preoperative physical function and more pain than their Boston counterparts. In patients with lower preoperative physical function, function and pain were not improved postoperatively to the level achieved by those with higher preoperative function. This was most striking in patients undergoing total knee replacement. CONCLUSION: Surgery performed later in the natural history of functional decline due to OA of the knee, and possibly of the hip, results in worse postoperative functional status.


5. Predicting the outcome of total knee arthroplasty.

J Bone Joint Surg Am. 2004 Oct;86-A(10):2179-86.

Lingard EA, Katz JN, Wright EA, Sledge CB; Kinemax Outcomes Group.

BACKGROUND: The relief of pain and the restoration of functional activities are the main outcomes of primary total knee arthroplasty for the treatment of osteoarthritis. This paper examines the preoperative predictors of pain and functional outcome at one and two years following total knee arthroplasty. METHODS: Patients were recruited for a prospective observational study of primary total knee arthroplasty for the treatment of osteoarthritis from centers in the United States, the United Kingdom, and Australia. Research assistants recruited the patients and collected the clinical history and physical examination data preoperatively and at three, twelve, and twenty-four months postoperatively. The Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Short Form-36 (SF-36), and demographic data were obtained by self-administered patient questionnaires. RESULTS: We recruited 860 patients and obtained one-year WOMAC data on 759 patients (88%) and two-year data on 701 (82%). The mean age was seventy years, and 59% of the patients were female. Using hierarchical regression models, we found that the most significant preoperative predictors of worse scores on the pain and function domains of the WOMAC scale and on the physical functioning domain of the SF-36 at one and two years postoperatively were low preoperative scores, a higher number of comorbid conditions, and a low SF-36 mental health score. After adjusting for these predictors, we found that the functional status of the patients from the United Kingdom was significantly worse than that of the patients from the other countries and the difference was clinically important at both the one-year and two-year follow-up examination (p < 0.0005). The mean WOMAC pain scores for the three countries were not significantly different at one year, and, although they were significantly different at two years (p = 0.025), the difference was not clinically important. CONCLUSIONS: Patients who have marked functional limitation, severe pain, low mental health score, and other comorbid conditions before total knee arthroplasty are more likely to have a worse outcome at one year and two years postoperatively. After adjusting for these predictors, it was found that patients from the United Kingdom had significantly worse functional outcomes but similar pain relief compared with those from the United States and Australia.

1. Total hip and knee arthroplasty in nonagenarians.

J Arthroplasty. 2007 Sep;22(6):807-11.

Alfonso DT, Howell RD, Strauss EJ, Di Cesare PE.

Among 25 patients of mean age 91.5 years (range, 90-96 years) who received a total hip or knee arthroplasty at the authors’ institution, 8% experienced surgical complications, 56% experienced at least 1 medical complication, and 80% received perioperative blood transfusions. At a mean follow-up of 4.1 years, patients were experiencing pain reduction and somewhat higher functional capacity and had slightly better survival characteristics than age-matched controls. Total hip and knee arthroplasty patients in this cohort should be told that they have a higher likelihood of experiencing perioperative medical complications and of receiving a blood transfusion than younger individuals; at the same time, they can expect pain relief as well as equal or better survival than their age-matched peers.


1. The impact of tobacco use and body mass index on the length of stay in hospital and the risk of post-operative complications among patients undergoing total hip replacement.

J Bone Joint Surg Br. 2006 Oct;88(10):1316-20.

Sadr Azodi O, Bellocco R, Eriksson K, Adami J.

We carried out a retrospective cohort study of 3309 patients undergoing primary total hip replacement to examine the impact of tobacco use and body mass index on the length of stay in hospital and the risk of short term post-operative complications. Heavy tobacco use was associated with an increased risk of

systemic post-operative complications (p = 0.004). Previous and current smokers had a 43% and 56% increased risk of systemic complications, respectively, when compared with non-smokers. In heavy smokers, the risk increased by 121%. A high body mass index was significantly associated with an increased mean length of stay in hospital of between 4.7% and 7%. The risk of systemic complications was

increased by 58% in the obese. Smoking and body mass index were not significantly related to the development of local complications. Greater efforts should be taken to reduce the impact of preventable life style factors, such as smoking and high body mass index, on the post-operative course of total hip replacement.

2. Obesity and perioperative morbidity in total hip and total knee arthroplasty patients.

J Arthroplasty. 2005 Oct;20(7 Suppl 3):46-50.

Namba RS, Paxton L, Fithian DC, Stone ML.

The incidence of obesity in 1071 total hip arthroplasty (THA) patients and 1813 total knee arthroplasty (TKA) patients and its effect on perioperative morbidity were evaluated prospectively. Fifty-two percent of TKA and 36% of THA patients were obese (body mass index >or=30). The obese patients were significantly younger, with a higher proportion of obese TKA patients being women. Higher rates of diabetes and hypertension were found in obese patients. Higher postoperative infection rates were observed in patients with body mass index 35 or higher. The odds ratio was 6.7 times higher risk for infection in obese TKA patients and 4.2 times higher for obese THA patients. The increased risk of infection in obese

patients undergoing total joint arthroplasty must be realized by both the patient and surgeon.

3. High body mass index is associated with increased risk of implant dislocation following primary total hip replacement: 2,106 patients followed for up to 8 years.

Acta Orthop. 2008 Feb;79(1):141-7.

Sadr Azodi O, Adami J, Lindström D, Eriksson KO, Wladis A, Bellocco R.

BACKGROUND AND PURPOSE: Implant dislocation is one of the commonest complications following primary total hip replacement (THR). We investigated the effect of body mass index (BMI) and tobacco use on the risk of this complication. SUBJECTS AND METHODS: Through linkage between the Swedish Construction Workers’ cohort and the Swedish Inpatient Register, 2,106 male patients who had undergone primary THR between 1997 and 2004 were identified. We used Cox multivariable regression analysis to study the association between BMI and tobacco use and the risk of implant dislocation. RESULTS: 53 patients (2.5%) developed implant dislocation during a mean of 2 (0-3) years of follow-up. We found overweight and obesity to be associated with increased risk of implant dislocation (HR = 2.5,95% CI: 1.1-5.5 and HR = 3.7, 95% CI: 1.5-9.3, respectively as compared to those of normal weight). There was no statistically significant association between tobacco use and the risk of dislocation.

4. Effect of smoking on early complications after elective orthopaedic surgery.

J Bone Joint Surg Br. 2003 Mar;85(2):178-81.

Møller AM, Pedersen T, Villebro N, Munksgaard A.

Smoking is an important risk factor for the development of postoperative pulmonary complications after major surgical procedures. We studied 811 consecutive patients who had undergone hip or knee arthroplasty, recording current smoking and drinking habits, any history of chronic disease and such intraoperative factors as the type of anaesthesia and the type and duration of surgery. We recorded any postoperative complications occurring before discharge from hospital. There were 232 smokers (28.6%) and 579 non-smokers. We found that smoking was the single most important risk factor for the development of postoperative complications, particularly those relating to wound healing cardiopulmonary complications, and the requirement of postoperative intensive care. A delay in discharge from hospital was usual for those suffering a complication. In those patients requiring prolonged hospitalisation (>15 days) the proportion of smokers with wound complications was twice that of non-smokers.

5. Obese diabetic patients are at substantial risk for deep infection after primary TKA.

Clin Orthop Relat Res. 2009 Jun;467(6):1577-81.

Dowsey MM, Choong PF.

We conducted a prospective study of 1214 consecutive primary TKAs to compare the deep prosthetic infection rate between obese and nonobese patients during the first 12 months after surgery. We also sought to determine whether patient or surgical variables such as comorbidities, age, gender, blood transfusion, use of  surgical drains, and antibiotic-impregnated cement were predictors of subsequent prosthetic infection after primary TKA. The overall prosthetic infection rate was 1.5% (n = 18). The odds for a deep prosthetic infection were greater in patients with morbid obesity (odds ratio [OR], 8.96; 95% confidence interval, 1.59-50.63) and diabetes (OR, 6.87; 95% confidence interval, 2.42-19.56). Men were more likely to have a prosthetic infection develop than women (OR, 5.93; 95% confidence interval, 1.95-18.04) and the prosthetic infection rate was lower (OR, 0.24; 95% confidence interval, 0.06-0.95) in patients when a surgical drain was used. There were no prosthetic infections in patients with diabetes who were not obese. This compares with 11 prosthetic infections in patients who were obese and diabetic and four prosthetic infections in patients who were obese but not diabetic. Morbid obesity and obesity combined with diabetes are risk factors for periprosthetic infection after TKA.

However some other studies suggest obese patients also get functional benefit following arthroplasty. On balance, it would be appropriate to reduce the risk factors as much as possible prior to joint replacement.