Source

Department of Health Services Research & Policy, London School of Hygiene & Tropical Medicine, UK. Andrew.hutchings@lshtm.ac.uk

Abstract

BACKGROUND:

Patient-reported outcome measures are increasingly being used to compare providers. We studied whether non-response rates to post-operative questionnaires are associated with patients' characteristics and organisational features of providers.

METHODS:

131,447 patients who underwent a hip or knee replacement, hernia repair or varicose vein surgery in 2009-10 in England. Multivariable logistic regression to calculate adjusted odds ratios of non-response for characteristics of the patients and organisational characteristics of providers. Multiple imputation was used for missing patient characteristics. Providers were included as random effects.

RESULTS:

Response rates to the post-operative questionnaire were 85.1% for hip replacement (n = 37 961), 85.3% for knee replacements (n = 44 422), 72.9% for hernia repair (n = 34 964), and 64.8% for varicose vein surgery (n = 14 100). Across the four procedures, there were higher levels of non-response in men (odds ratios 1.03 [95% CI 0.95-1.11] - 1.35 [1.25-1.46]), younger patients (those under 55 years 3.01 [2.72-3.32] - 6.05 [5.49-6.67]), non-white patients (1.24 [1.11-1.38] - 2.08 [1.89-2.31]), patients in the most deprived quintile of socio-economic status (1.47 [1.34-1,62] - 1.86 [1.71-2.03]), those who lived alone (1.11 [0.99-1.23] - 1.27 [1.18-1.36]) and those who had been assisted when completing their pre-operative questionnaire (1.26 [1.10-1.46] -1.67 [1.56-1.79]). Non-response rates were also higher in patients who had poorer pre-operative health (three or more comorbidities: 1.14 [0.96-1.35] - 1.45 [1.30-1.63]). Providers' patient recruitment rates before surgery and the timing of pre-operative questionnaire administration did not affect the rates of response to post-operative questionnaires.

CONCLUSION:

If non-response can be shown to be associated with outcome, then rates of non-response to post-operative questionnaires would need to be taken into account when these measures are being used to compare the performance of providers or to evaluate surgical procedures.

Source

Orthopaedics Department, Martina Hansens Hospital, Baerum, Norway. kjnerhus@gmail.com

Abstract

BACKGROUND AND PURPOSE:

10-year survival rates after unicompartmental knee replacement (UKR) have been up to 97% in single-center studies, but they have been as low as 80% in studies from arthroplasty registers. Few studies have evaluated short-term functional outcome and its improvement with time. We determined the time course of functional outcome as evaluated by the knee injury and osteoarthritis outcomescore (KOOS) over the first 2 years after Oxford medial UKR.

PATIENTS AND METHODS:

In a prospective multicenter study, we included 99 unselected knees (96 patients, mean age 65 (51-80) years, 57 women) operated with Oxford medial UKR at 3 hospitals in the southeast of Norway between November 2003 and October 2006. Data were collected by independent investigators preoperatively and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively. KOOS and range of motion (ROM) were determined at all follow-ups.

RESULTS:

Mean KOOS values for pain and activities of daily living were improved already after 6 weeks, and increased between each time point up to 2 years postoperatively. However, no statistically significant improvements were seen after 6 months. Mean active and passive ROM gradually improved up to 2 years after UKR, and were then better than before surgery.

INTERPRETATION:

Most of the expected improvements in pain and function after UKR are achieved within 6 months of surgery. Only minimal improvement can be expected beyond this time.

Comment on

• Outcome and reproducibility of data concerning the Oxford unicompartmental knee arthroplasty: a structured literature review including arthroplasty registry data. [Acta Orthop. 2011]
• Outcome of the cementless Taperloc stem: a comprehensive literature review including arthroplasty register data. [Acta Orthop. 2011]

Source

Department of Orthopaedics, Radboud University, Nijmegen Medical Centre, the Netherlands. hjmeijerink@hotmail.com

Abstract

BACKGROUND AND PURPOSE:

To try to improve the outcome of our TKAs, we started to use the CKS prosthesis. However, in a retrospective analysis this design tended to give worse results. We therefore conducted a randomized, controlled trial comparing this CKS prosthesis and our standard PFC prosthesis. Because many randomized studies between different TKA concepts generally fail to show superiority of a particular design, we hypothesized that these seemingly similar designs would not lead to any difference in clinical outcome.

PATIENTS AND METHODS:

82 patients (90 knees) were randomly allocated to one or other prosthesis, and 39 CKS prostheses and 38 PFC prostheses could be followed for mean 5.6 years. No patients were lost to follow-up. At each follow-up, patients were evaluated clinically and radiographically, and the KSS, WOMAC, VAS patient satisfaction scores and VAS for pain were recorded.

RESULTS:

With total Knee Society score (KSS) as primary endpoint, there was a difference in favor of the PFC group at final follow-up (p = 0.04). Whereas there was one revision in the PFC group, there were 6 revisions in the CKS group (p = 0.1). The survival analysis with any reoperation as endpoint showed better survival in the PFC group (97% (95% CI: 92-100) for the PFC group vs. 79% (95% CI: 66-92) for the CKS group) (p = 0.02).

INTERPRETATION:

Our hypothesis that there would be no difference in clinical outcome was rejected in this study. The PFC system showed excellent results that were comparable to those in previous reports. The CKS design had differences that had considerable negative consequences clinically. The relatively poor results have discouraged us from using this design.

Source

Kent and Sussex Hospital, Mount Ephraim Rd, Tunbridge Wells, Kent, TN4 8AT, UK. drmedmondson@hotmail.com

Abstract

BACKGROUND:

In our experience results of the Oxford unicompartmental knee replacement have not been as good as had been expected. A common post operative complaint is of persistent medial knee discomfort, it is not clear why this phenomenon occurs and we have attempted to address this in our study.

METHODS:

48 patients were retrospectively identified at a mean of 4.5 years (range = 3 to 6 years) following consecutive Oxford medial Unicompartmental Knee arthroplasties for varus anteromedial osteoarthritis. The mean age at implantation was 67 years (range 57-86). Of these 48 patients, 4 had died, 4 had undergone revision of their unicompartmental knee replacements and 2 had been lost to follow up leaving 38 patients with 40 replaced knees available for analysis using the 'new Oxford Knee Score' questionnaire. During assessment patients were asked specifically whether or not they still experienced medial knee discomfort or pain.

RESULTS:

The mean 'Oxford score' was only 32.7 (range = 16 to 48) and 22 of the 40 knees were uncomfortable or painful medially.The accuracy of component positioning was recorded, using standard post operative xrays, by summing the angulation or displacement of each component in two planes from the ideal position (according to the 'Oxford knee system radiographic criteria'). No correlation was demonstrated between the radiographic scores and the 'Oxford scores', or with the presence or absence of medial knee discomfort or pain.

CONCLUSION:

In our hands the functional outcome following Oxford Unicompartmental knee replacement was variable, with a high incidence of medial knee discomfort which did not correlate with the postoperative radiographic scores, pre-op arthritis and positioning of the prosthesis.

Source

Department of Orthopedics, Holstebro Regional Hospital, Hostebro. stigmunk@rm.dk

Abstract

BACKGROUND AND PURPOSE:

There is disagreement in the literature about the importance of patellofemoral joint degeneration and knee pain for the outcome of unicompartmental knee arthroplasty (UKA). We therefore investigated the importance of selected predictors including patellofemoral joint degeneration and the location of preoperative knee pain for the early outcome of UKA.

PATIENTS AND METHODS:

The study group comprised 260 consecutive patients from 5 hospitals who underwent Oxford UKA for anteromedial osteoarthritis. Data were collected at baseline and included pain location, radiologically observed degeneration of the patellofemoral joint including subluxation of the patella, intraoperative cartilage status of the patellofemoral joint, disease-specific knee status, and Oxford knee score (OKS). Outcomes were evaluated after 1 year using the OKS, global patient satisfaction, and global patient result.

RESULTS:

The average OKS score at baseline was 24 (SD 7), and it was 40 (SD 8) at the 1-year follow-up. 94% of the patients claimed improvement after the operation and 90% were satisfied with the UKA. Lateral subluxation of the patella was a predictor of poor outcome, and the preoperative OKS score was also a predictor of outcome. Full-thickness cartilage loss at any location gave a similar outcome to that with a normal or near-normal joint surface, and likewise, preoperative anterior knee pain was not a predictor of outcome.

INTERPRETATION:

We conclude that the good early outcome after UKA in this study is in line with the best reported results. Patellofemoral degeneration should not be considered a contraindication to Oxford UKA. Patients with lateral subluxation of the patella have an increased risk of a poor result after UKA and should preferably be offered a total knee replacement.

Source

The University of Melbourne (Parkville Campus), Victoria 3010, Australia. m.alviar@pgrad.unimelb.edu.au

Abstract

OBJECTIVE:

The aim of this study was to systematically review and compare the measurement attributes of multidimensional, patient-reported outcome measures used in hip and knee arthroplasty rehabilitation.

METHODS:

A search of PubMed, CINAHL, Cochrane Central Registry, SCOPUS and PEDro databases up to December 2009 identified the validation studies. The quality of the measurement properties were assessed based on the Terwee and Bot criteria, and Scientific Advisory Committee of the Medical Outcomes Trust guidelines.

RESULTS:

A total of 68 studies examining 28 instruments were identified. Three instruments had positive ratings for content validity. None of the instruments satisfied both factor analysis and Cronbach's α criteria for internal consistency. Four measures were positively-rated for agreement. Nine tools had positive ratings for construct validity. Twenty-four of the instruments had indeterminate ratings for responsiveness to clinical change. Only certain subscales of 2 instruments were positively-rated for responsiveness to clinical change.

CONCLUSION:

A wide variety of multidimensional patient-reported instruments has been used to assess rehabilitation outcomes after hip and knee arthroplasty, but information about their measurement attributes in these populations is inadequate. More data are needed to clarify their reproducibility and responsiveness to clinical change. :

Source

Haugesund Hospital, Haugesund, Norway. oystein.gothesen@helse-fonna.no

Abstract

BACKGROUND:

and purpose Improvement of positioning and alignment by the use of computer-assisted surgery (CAS) might improve longevity and function in total knee replacements, but there is little evidence. In this study, we evaluated the short-term results of computer-navigated knee replacements based on data from the Norwegian Arthroplasty Register.

PATIENTS AND METHODS:

Primary total knee replacements without patella resurfacing, reported to the Norwegian Arthroplasty Register during the years 2005-2008, were evaluated. The 5 most common implants and the 3 most common navigation systems were selected. Cemented, uncemented, and hybrid knees were included. With the risk of revision for any cause as the primary endpoint and intraoperative complications and operating time as secondary outcomes, 1,465 computer-navigated knee replacements (CAS) and 8,214 conventionally operated knee replacements (CON) were compared. Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex, prosthesis brand, fixation method, previous knee surgery, preoperative diagnosis, and ASA category were used.

RESULTS:

Kaplan-Meier estimated survival at 2 years was 98% (95% CI: 97.5-98.3) in the CON group and 96% (95% CI: 95.0-97.8) in the CAS group. The adjusted Cox regression analysis showed a higher risk of revision in the CAS group (RR = 1.7, 95% CI: 1.1-2.5; p = 0.02). The LCS Complete knee had a higher risk of revision with CAS than with CON (RR = 2.1, 95% CI: 1.3-3.4; p = 0.004)). The differences were not statistically significant for the other prosthesis brands. Mean operating time was 15 min longer in the CAS group.

INTERPRETATION:

With the introduction of computer-navigated knee replacement surgery in Norway, the short-term risk of revision has increased for computer-navigated replacement with the LCS Complete. The mechanisms of failure of these implantations should be explored in greater depth, and in this study we have not been able to draw conclusions regarding causation.

Source

Department of Medicine (RMH), The University of Melbourne, Melbourne, Australia. m.alviar@pgrad.unimelb.edu.au

Abstract

OBJECTIVE:

To compare the contents of patient-reported instruments used in hip and knee arthroplasty rehabilitation with the International Classification of Functioning, Disability and Health (ICF).

METHODS:

A search of PubMed, CINAHL, Cochrane Central Registry, SCOPUS and PEDro identified patient-reported outcome instruments. The meaningful concepts extracted from the instruments were linked to the ICF based on established linking rules and compared with the osteoarthritis core set. The number of concepts per item, the breadth, and the depth of coverage of instruments in relation to the ICF were determined through calculation of content density, bandwidth per ICF component, and content diversity, respectively.

RESULTS:

Eight instruments were reviewed and 375 meaningful concepts were linked to the ICF. Activity and participation had the most representation (61%). The Hip Disability and Osteoarthritis Outcome Score and Knee Injury and Osteo-arthritis Outcome Score had the widest coverage (bandwidth) for body functions (1.62%, 1.22%, respectively). The Arthritis Impact Measurement Scales had the broadest bandwidth (8.4%) for activity and participation. All tools addressed general mobility but lacked coverage in "driving", "assisting others", "interpersonal relationships" and "community life". The majority of tools did not address environmental factors.

CONCLUSION:

Patient-reported outcome measures in arthroplasty rehabilitation do not fully address relevant areas of activity, participation and environment, suggesting limited clinical applicability.

Source

Department of Orthopaedics, Innsbruck Medical University, Innsbruck, Austria.

Abstract

BACKGROUND AND PURPOSE:

The reproducibility of results and potential confounders in sample-based studies is important to consider in the assessment of studies. Comprehensive arthroplasty registers could serve as a reference dataset for comparative analyses. We analyzed an implant that is frequently used worldwide, the Oxford unicompartmental knee replacement, in order to identify potential confounders inherent in the datasets and to evaluate the outcome achieved with this implant.

METHODS:

We performed a structured literature review of the data published on the revision rate of the Oxford medial unicompartmental arthroplasty. Both clinical follow-up studies and worldwide registry data were included. Confidence intervals were calculated to determine the statistical significance of differences.

RESULTS:

A substantial proportion of the published data (52-68% depending on the method of calculation) is derived from studies involving participation of the institution that developed the implant. The results published by this group show a statistically significant deviation from the reference datasets from registers or independent studies. Data from the developing hospital show mean revision rates that are 4 times lower than those based on worldwide register data, and 3 times lower than the ones quoted in independent studies. On average, the data published in independent studies are reproducible in registry data.

INTERPRETATION:

A conventional meta-analysis of clinical studies is substantially affected by the influence of the developing hospital, and is therefore subject to bias. For assessment of the outcome of implants, registry data are superior and, in terms of reference data for the detection of potential bias factors in the literature, could make an essential contribution to meta-analyses.

Comment in

• Outcome of the cementless Taperloc stem. [Acta Orthop. 2011]

Comment on

• Differences in outcome between Maori and Caucasian patients undergoing total joint arthroplasty for osteoarthritis. [J Orthop Surg (Hong Kong). 2010]

Source

Martina Hansens Hospital, Baerum, Norway. kjetil@legesiden.no

Abstract

BACKGROUND AND PURPOSE:

Long-term follow-up studies after total knee replacement (TKR) using an LCS rotating platform have shown survival rates of up to 97%. Few studies have evaluated short-term functionaloutcome and its improvement over time. We determined the time course of functional outcome as evaluated by the knee injury and osteoarthritis outcome score (KOOS) over the first 4 years after TKR using the LCS mobile bearing.

PATIENTS AND METHODS:

50 unselected patients (mean age 70 (40-85) years, 33 women) with osteoarthritis in one knee underwent TKR with an LCS mobile bearing. Data were collected by an independent investigator preoperatively and at 6 weeks, 3 months, 6 months, 1 year, 2 years and 4 years postoperatively. KOOS, a self-assessment function score validated for this purpose, and range of motion (ROM) were determined at all follow-ups.

RESULTS:

The mean KOOS pain score increased from 43 before surgery to 66 at 6 weeks and 88 at 2 years. It was 84 at 4 years. The mean KOOS activities of daily living score (ADL) increased from 49 before surgery to 73 at 6 weeks, then gradually to 90 at 2 years. It decreased to 79 at 4 years. Mean passive ROM was 112° before surgery, 78° at departure from hospital, and then gradually increased to 116° at 2 years and 113° at 4 years.

INTERPRETATION:

Recovery after TKR is time-dependent. Most of the expected improvement in pain and function is achieved at 6 months postoperatively, but some further improvement can be expected up to 2 years postoperatively. ROM will also gradually improve up to 2 years after TKR, and reach the same level as before surgery.

Source

Department of Orthopaedic Surgery and Traumatology, Atrium Medical Centre, PO Box 4446, 6401 CX, Heerlen, The Netherlands. wht02@atriummc.nl

Abstract

PURPOSE:

In total knee arthroplasty, tissue-sparing techniques are considered more important, as functional gain could become more advantageous when early mobilization is commenced. The parapatellar approach is most often used, whereas the subvastus approach is a suitable alternative. Presently, it is unknown, according to true objective measurements, which of the two is most advantageous.

METHODS:

In this prospective randomized double-blind, short-term trial measurements (KSS, WOMAC, PDI, VAS, ability to perform) were obtained at day 1, day 3, 1 week, 6 weeks, and 3 months.

RESULTS:

The subvastus group (n=20) showed only significantly less extension lag direct postoperative (P=0.04) compared with the parapatellar group (n=20). Other scores were not significantly different. The Dynaport®knee test, an objective performance-based tool, could not demonstrate significant differences. A blunt anatomical dissection was carried out in both observational and histological to support findings. A dense innervation of the distal vastus medialis was found. This is at risk employing the subvastus approach. Both approaches harm the suprapatellar bursa. The vastus medialis sheath must be detached distally to open the knee joint. No true separate vastus medialis obliquus could be identified.

CONCLUSION:

Comparable to literature, only mild advantage employing the subvastus approach was found, but only early postoperative and not objectively. As this approach is also not suitable in every case, we will continue to use the parapatellar approach.

Source

Klinik für Orthopädische Chirurgie und Traumatologie des Bewegungsapparates, Rorschacherstrasse 97, 9007, St. Gallen, Switzerland.

Abstract

PURPOSE:

Computer-assisted surgery (CAS) for total knee arthroplasty (TKA) has become increasingly common over the last decade. There are several reports including meta-analyses that show improved alignment, but the clinical results do not differ. Most of these studies have used a bone referencing technique to size and position the prosthesis. The question arises whether CAS has a more pronounced effect on strict ligamentous referencing TKAs.

METHODS:

We performed a prospective cohort study comparing clinical outcome of navigated TKA (43 patients) with that of conventional TKA (122 patients). Patients were assessed preoperatively, and 2 and 12 months postoperatively by an independent study nurse using validated patient-reported outcome tools as well as clinical examination.

RESULTS:

At 2 months, there was no difference between the two groups. However, after 12 months, CAS was associated with significantly less pain and stiffness, both at rest and during activities of daily living, as well as greater overall patient satisfaction.

CONCLUSION:

The present study demonstrated that computer-navigated TKA significantly improves patientoutcome scores such as WOMAC score (P=0.002) and Knee Society score (P=0.040) 1 year after surgery in using a ligament referencing technique. Furthermore, 91% were extremely or very satisfied in the CAS TKA group versus 70% after conventional TKA (P=0.007).

Source

Gisborne Hospital, New Zealand. vasuchitra@gmail.com

Abstract

PURPOSE:

To compare differences in outcome between Maori and Caucasian patients undergoing total joint arthroplasty for osteoarthritis.

METHODS:

45 men and 45 women aged 43 to 87 years who underwent total hip (n=54) or total knee (n=36) arthroplasties by a single surgeon and were followed up for at least one year were prospectively studied. Patients were classified according to American Society of Anesthesiologists (ASA) score. Preoperative comorbidity, length of hospital stay, postoperative complications, and pre- and post-operative outcomes in the 2 groups were compared.

RESULTS:

Maori patients were more likely than Caucasian patients to be obese (body mass index of >30 kg/m square) [37% vs. 15%], diabetic (15% vs. 5%), and smokers (32% vs. 13%). Postoperative complication rates and the lengths of hospital stay in the 2 groups were not significantly different. The ASA score correlated positively with the length of hospital stay; higher ASA scores predicted more prolonged recovery.

CONCLUSION:

Maori patients were more likely than Caucasian patients to have preoperative comorbidities, but their postoperative length of hospital stay and complication rates were not significantly different.

Comment in

• Letter to the editor: Differences in outcome between Maori and Caucasian patients undergoing total joint arthroplasty for osteoarthritis. [J Orthop Surg (Hong Kong). 2010]

Source

Department of Anesthesia, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada. franco.carli@mcgill.ca

Abstract

BACKGROUND:

Capacity to ambulate represents an important milestone in the recovery process after total knee arthroplasty (TKA). The purpose of this study was to determine the analgesic effect of two analgesic techniques and their impact on functional walking capacity as a measure of surgical recovery.

METHODS:

Forty ASA II-III subjects undergoing TKA were enrolled in a randomized, double-blind, single-centre study receiving 48 h postoperative analgesia with either periarticular infiltration of local anaesthetic (Group I) or continuous femoral nerve block (Group F). Breakthrough pain relief was achieved with patient-controlled analgesia (PCA) morphine. The main outcome was postoperative morphine consumption. Early (postoperative days 1-3) and late (6 weeks) functional walking capacity (2 and 6 min walk tests, 2MWT and 6MWT, respectively), degree of physical activity (CHAMPS), health-related quality of life (SF-12), and clinical indicators of knee function (WOMAC, Knee Society evaluation, and range of motion) were measured.

RESULTS:

Patients in Group F used the PCA less (P=0.02) to achieve adequate analgesia. Postoperative 2MWT was similar in both groups (P=0.27). Six weeks after surgery, recovery of 6MWT, physical activity, and knee function were significantly improved in Group F (P<0.05). Preoperative walking capacity, physical activity and early total walking time were the independent predictors of early recovery. Distance and time spent walking were the predictors of functional walking exercise capacity at 6 weeks after surgery.

CONCLUSIONS:

Femoral block is associated with lower opioid consumption and a better recovery at 6 weeks than periarticular infiltration. Early postoperative activity measures (2MWT and walking time) were proved to be possible indicators of knee function recovery at 6 weeks after surgery.

Source

Specialist Orthopaedic Group, Suite 1.08, Level 1, Mater Clinic, 3-9 Gillies Street, Sydney, New South Wales, Australia. ericyeung259@yahoo.co.uk

Abstract

The aim of this study was to evaluate the outcome of joint arthroplasty in obese and non-obese patients. We reviewed 2,026 consecutive primary total hip and 535 primary total knee arthroplasties performed for osteoarthritis. Patients were separated into two groups according to their body mass index (BMI): non-obese (BMI < 30) and obese (BMI ≥ 30). Their survivorships were compared. Case controlled studies were performed with 134 hip and 50 knee arthroplasties in obese patients. Each was matched individually with a control and their outcome compared. Log rank tests for equality of survival showed no difference in the survival for hip and knee arthroplasty at 11 and ten years, respectively. The obese group had significantly lower postoperative hip and knee scores at latest follow-up, especially in the range of motion. Overall patient satisfaction scores were comparable. There were no significant differences in the radiographic analysis of both hip and knee implants. Revision was used as an end point for the survival analysis. Functional scores (Harris hip score and Hospital for Special Surgery knee score), satisfaction for surgery and radiographic features were used as outcomemeasures for comparison. The mid-term survival of total hip and knee arthroplasty is not adversely affected by obesity. Despite lower clinical scores, the obese patients were satisfied with the results of their surgery and have an equivalent mid-term survival rate. It would be unreasonable to deny patients arthroplasty surgery purely on the basis of a BMI indicating obesity.

Source

Faculty of Medicine, Bone and Cartilage Unit, University of Kuopio, Kuopio, Finland. jaakko.jarvenpaa@fimnet.fi

Abstract

BACKGROUND AND AIMS:

Obesity has been linked to the development of osteoarthritis of the knee and increases the probability to fall into total knee arthroplasty. In this study we compared short-term outcome of total knee arthroplasty (TKA) in non-obese and obese patients.

MATERIAL AND METHODS:

A total of 100 patients underwent TKA between October 2006 and March 2007. They were divided into two groups based on the body mass index: 52 of the patients were obese (BMI = 30 kg/m2) and 48 non-obese (BMI < 30 kg/m2). The short-term out-come was studied using clinical, functional and radiological analysis. The mean of the follow-up period was 3 months.

RESULTS:

There were five complications (2 wound infections, phlebitis, nerve injury and massive edema) in obese patients group compared with no complications in non-obese (p = 0.028). The obese patients had also worse postoperative range of motion (110 degrees vs.118 degrees , p = 0.001) than non-obese and the number of technical errors was 17 in obese and 5 in non-obese group, respectively (p = 0.007).

CONCLUSIONS:

We suggest that obesity may impair the early outcome of total knee arthroplasty and obese patients should be informed about the increased risk of complications related to TKA. Key words: Total knee arthroplasty; body mass index; obesity; complications; range of motion; mechanical axis.

Source

Baylor College of Medicine, 6620 Main, Suite 1325, Houston, TX, 77030, USA. bparsley@bcm.tmc.ed

Abstract

BACKGROUND:

Previous studies suggest differences may exist between men and women in terms of knee function before and after total knee replacement. This may be related to the efficacy of the procedure itself or to differences in the severity of disability of male and female patients at the time of surgery.

QUESTIONS/PURPOSES:

We evaluated differences in the age, preoperative deformity, range-of-motion, and Knee Society scores of men and women who underwent TKA. All parameters were measured at the time of the initial preoperative evaluation and at postoperative followup.

METHODS:

We studied 698 patients who underwent elective TKA between 1996 and 2007. This population consisted of 428 women (61%) and 270 men (39%), all of whom underwent rehabilitation utilizing a standardized hyperflexion protocol with immediate initiation of full weight-bearing postoperatively.

RESULTS:

The men were on average three years younger than the women (mean 63.5 versus 66.6 years, respectively). Preoperative ROM, postoperative ROM, and changes in ROM and body mass index were similar between groups. Knee Society Knee scores were similar preoperatively (47.4 [men] versus 46.7 [women]), but four points higher in men at followup (89.2 versus 85.2). Women had lower Knee Function scores than men preoperatively (45.2 versus 57.1), and postoperatively (65.3 versus 73.9).

CONCLUSIONS:

Women who undergo TKA seek treatment at a later stage than men and have greater functional disability at the time of surgery. Differences in functional scores persist after TKA. Earlier initiation of treatment may enhance postoperative outcome.

LEVEL OF EVIDENCE:

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Source

The Rothman Institute of Orthopedics at Thomas Jefferson University, 925 Chestnut Street, 5th Floor, Philadelphia, PA 19107, USA.

Abstract

BACKGROUND:

Periprosthetic joint infection after TKA is a challenging complication. Two-stage exchange arthroplasty is the accepted standard of care, but reported failure rates are increasing. It has been suggested this is due to the increased prevalence of methicillin-resistant infections.

QUESTIONS/PURPOSES:

We asked the following questions: (1) What is the reinfection rate after two-stage exchange arthroplasty? (2) Which risk factors predict failure? (3) Which variables are associated with acquiring a resistant organism periprosthetic joint infection?

METHODS:

This was a case-control study of 102 patients with infected TKA who underwent a two-stage exchange arthroplasty. Ninety-six patients were followed for a minimum of 2 years (mean, 34.5 months; range, 24-90.1 months). Cases were defined as failures of two-stage exchange arthroplasty.

RESULTS:

Two-stage exchange arthroplasty was successful in controlling the infection in 70 patients (73%). Patients who failed two-stage exchange arthroplasty were 3.37 times more likely to have been originally infected with a methicillin-resistant organism. Older age, higher body mass index, and history of thyroid disease were predisposing factors to infection with a methicillin-resistant organism.

CONCLUSIONS:

Innovative interventions are needed to improve the effectiveness of two-stage exchange arthroplasty for TKA infection with a methicillin-resistant organism as current treatment protocols may not be adequate for control of these virulent pathogens.

LEVEL OF EVIDENCE:

Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.