Blood, bugs, and motion: what do we really know in regard to total joint arthroplasty?
Abstract: In total joint arthroplasty, it is often necessary to formulate decisions that are not clearly evidence-based. This review presents some current controversial topics in total joint arthroplasty, including preoperative autologous blood donation versus erythropoietin (EPO) usage, preoperative screening and treatment for methicillin resistant Staphylococcus aureus (MRSA), and the use of continuous passive motion (CPM) following total knee arthroplasty, providing an evidence-based guide for the treating orthopaedic surgeon. Our review shows that preoperative autologous blood donation is over utilized, with EPO being under utilized. Surgeons are encouraged to develop patient-specific strategies, which have been shown to decrease transfusion rates, reduce wasted autologous blood, and increase EPO use.

Definitive conclusions regarding MRSA screening for orthopaedic patients cannot be drawn; but due to the significant cost and morbidity associated with a postoperative MRSA infection, we believe a screen and treat protocol should be considered for all patients being admitted to the hospital for elective or emergent surgery. Short-term (3 to 5 days) inpatient use of CPM is recommended at this time. It is low-cost, has minimal risk, and may be a factor in decreasing the length of stay, potentially leading to significant cost savings. However, no long-term benefits of CPM use have been established.
Subject: Joint replacement (Methods)
Joint replacement (Forecasts and trends)
Preoperative care (Methods)
Staphylococcus aureus infections (Diagnosis)
Staphylococcus aureus infections (Care and treatment)
Erythropoietin (Dosage and administration)
Blood transfusion (Usage)
Continuous passive motion therapy (Usage)
Authors: Glassner, Philip J.
Slover, James D.
Bosco, Joseph A.
Zuckerman, Joseph D.
Pub Date: 01/01/2011
Publication: Name: Bulletin of the NYU Hospital for Joint Diseases Publisher: J. Michael Ryan Publishing Co. Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 J. Michael Ryan Publishing Co. ISSN: 1936-9719
Issue: Date: Jan, 2011 Source Volume: 69 Source Issue: 1
Topic: Event Code: 010 Forecasts, trends, outlooks Computer Subject: Market trend/market analysis
Accession Number: 289216175
Full Text: In total joint arthroplasty (TJA), it is often necessary to formulate decisions that are not necessarily based on clear evidence-based criteria. As well, there is often supporting data for multiple answers to the same question, leading many decisions to be based simply on surgeon preference. Furthermore, if a surgeon has performed hundreds of cases with good clinical outcomes, concrete scientific evidence would be needed in order to institute a change in his protocol. This review will present some of the current controversial topics in total joint arthroplasty, including preoperative autologous blood donation versus erythropoietin (EPO) usage, preoperative screening and treatment for methicillin resistant Staphylococcus aureus (MRSA), and the use of continuous passive motion (CPM) following total knee arthroplasty (TKA), providing an evidence-based guide for the treating orthopaedic surgeon.

Preoperative Autologous Blood Donation Versus Erythropoetin

The impetus for autologous blood transfusion began in the 1980s, secondary to concerns over disease transmission with allogeneic blood transfusion in the face of HIV. This continued through the 1990s and to the present day, with the added concerns of possible hepatitis B and C infection from a blood transfusion. The screening process for blood borne pathogens has improved, but the risk of transmission of common viruses is still estimated to be 1/493,000 for HIV, 2/63,000 for hepatitis B, and 1/103,000 for hepatitis C. (1) Even more worrisome is the risk of administrative error, with roughly one incorrect unit given per 19,000 units being transfused. It is possible that the true risk is closer to one in 12,000 units, due to under reporting of adverse events. The majority of these errors can be easily avoided, as 43% occur from failure to identify the patient or unit, or both, prior to transfusion. (2) Consequently, both physicians and patients remain cautious about allogeneic blood transfusions.

This being said, it is not clear that autologous blood donation is the answer. Many autologous donated units are never used and are discarded. Additionally, patients who receive their autologous units may still require allogeneic blood transfusions postoperatively. Further, there are currently no definitive guidelines dictating who should pre-donate autologous blood.

The general guidelines for autologous pre-donation of blood prior to primary TJA are based on the patient's pre-operative hemoglobin level. Patients with an Hgb greater than13 g/dl are given the option to pre-donate; those with an Hgb of 10 to 13 g/dl are advised against pre-donating, as the preoperative blood draw would further decrease their Hgb, increasing the need for allogeneic transfusion. Those patients with an Hgb under 10 g/dl should have a hematologic evaluation to elicit the underlying cause of their anemia and should be treated preoperatively. (3) What does this mean for the patients who pre-donate, and what should be done for the patients with Hgb between 10 to 13 g/dl?

Approximately 44% of the pre-donated autologous units are discarded3 and roughly 14% of patients who pre-donate still require allogeneic blood transfusions. (4) One potential solution, as well as the answer regarding the patients with Hgb 10 to 13 g/dl, is the use of erythropoietin (EPO). Erythropoietin is a naturally occurring glycoprotein that causes stimulation of red blood cell production in the bone marrow. Recombinant human EPO has the exact same amino acid sequence as endogenous EPO and functions in the same manner to increase hemoglobin levels. The first orthopaedic studies regarding EPO were performed in the mid-1990s and showed promising results; however, the use of EPO prior to TJA is still relatively rare.

Current Evidence

In a prospective cohort study by Bern and colleagues, (5) 430 patients undergoing primary TKA were separated into two groups: those that pre-donated autologous blood and those that did not pre-donate. The investigators looked at several variables, including the quantity of transfusions required (autologous and allogeneic), age, pre-and postoperative Hgb levels, and surgical blood loss. They found that 64% of the non-donator group required postoperative transfusion versus 83% in the autologous group. However, only 21% of patients in the autologous group received allogeneic units (p < .0001), leading to a 37% rate of wasted autologous units. Certain patient characteristics led to decreased transfusion rates, including an age under 65, a higher preoperative Hgb greater than 13 g/dl, and a postoperative Hgb greater than 10 g/dl. Further, patients with operative blood loss greater than 400 ml were twice as likely to receive allogeneic transfusions as those with a blood loss less than 400 ml. When adjusted for all the above factors, pre-donation caused a four-fold increase in the likelihood of a postoperative transfusion, but this group did have a decreased need for allogeneic transfusion. The investigators concluded that the patients' Hgb did not increase sufficiently from the time of donation, and that a surgeon's threshold to transfuse may have been lower for patients who had autologous blood available. They felt that pre-donation of autologous blood was successful in regard to decreasing the need for allogeneic blood, but that the program needed re-evaluation to determine who should or should not be pre-donating. This study did not include patients receiving EPO.

Hatzidakis and coworkers (6) performed a retrospective analysis of 489 consecutive patients who underwent THA or TKA to identify the risk factors for allogeneic transfusion and to define the indications for preoperative autologous blood donation. The criteria for pre-donation were an Hgb greater than 11 g/dl and absence of active infection or uncontrolled cardiac disease. They found that autologous donation caused a significant decrease in the need for allogeneic blood transfusion (p < .0001), but 56% of the donated autologous blood was discarded. They also reported that patients at low risk of requiring a transfusion included patients undergoing primary THA or TKA, with a baseline Hgb greater than 15 g/dl, or baseline Hgb 13 to 15 g/dl and age less than 65, as none of these patients required allogeneic transfusions and only 17% received their pre-donated autologous units. Patients at increased risk included those undergoing a revision knee or hip procedure, or a one-stage bilateral primary knee replacement (relative risk, 5.7; p < 0.0001), those with an initial hemoglobin level of less than 13 g/dl (relative risk, 5.6; p < 0.0001), and an age of 65 years or older (relative risk, 2.8; p = 0.02). They also found intra-operative blood loss to be a factor, with those averaging less than 423 ml blood loss not requiring any transfusion, while those losing an average of 909 ml required autologous and allogeneic transfusions. They concluded that the efficiency of autologous blood collection could be improved by identifying patients at low risk of needing a transfusion and using this information to assist patients in making an informed decision about preoperative donation.

A prospective, randomized trial of 251 patients undergoing primary, unilateral THA or TKA was performed in 2007, to compare patients who underwent preoperative autologous donation (PAD) with patients who received human recombinant erythropoietin (EPO). The investigators evaluated the need for transfusion and the effect on postoperative vigor and handgrip strength. All patients had a baseline Hgb of 11 to 14 g/dl. (4) The EPO group received four total doses of 600 IU/kg: once weekly, beginning on preoperative day 21, with the final dose given within 24 hours postoperatively. Both groups received daily iron supplementation of 300 mg.

Preoperatively, hemoglobin levels increased from baseline in the EPO group (13 g/dl to 14.2 g/dl) and decreased from baseline in the PAD group (13 g/dl to 12.1 g/dl). Postoperatively, hemoglobin levels decreased in both groups during the first week and then started to return to baseline levels by day 14 to 21. They found that hemoglobin levels were comparable at baseline but were significantly higher in the EPO group at every post-baseline visit (p < .001). Three percent of patients in the EPO group and 65% of patients in the PAD group received blood transfusions during surgery or postoperatively, with allogeneic blood given to the four patients in the EPO group and to 17 (14%) of the patients in the PAD group (p < .002). Thirty-one percent of the autologous units were discarded. The mean pre-transfusion hemoglobin level in the EPO group was 8.13 g/dL; while in the PAD group, it was 8.97 g/dL (p < .001), again demonstrating a lower threshold for transfusion for the PAD group. They found no significant difference in regards to vigor or handgrip strength, although it was clear that patients in the EPO group had higher hemoglobin levels and required fewer transfusions.

For patients who are undergoing primary TJA, it seems that pre-donation of autologous blood may not be indicated when Hgb levels are greater than 15 g/dl or between 13 to 15 g/dl in those who are less than 65 years old. Further, it appears that EPO is quite beneficial for those with Hgb levels of 11 to 14 g/dl. This information has led to the development of specific transfusion strategies.

A study conducted in France, in 2007, implemented an algorithm for all patients undergoing a primary THA or TKA to evaluate the need for postoperative transfusion of allogeneic and autologous blood, as well as the use of EPO. (7) The algorithm was presented as a diagram to the anesthesiologist caring for the patient and was based on a patient's expected and tolerated blood losses. They analyzed 302 (initial evaluation) and 173 (post-implementation) arthroplasties and demonstrated a 55% reduction in the prescription for autologous blood donation, while the proportion of EPO prescriptions increased from 6.6% to 17.3% (p < 0.05). There was a 56% overall reduction in transfusions to fewer autologous (32% versus 12%, p < 0.0001) and allogeneic transfusions (21% versus 13%). Furthermore, 50% fewer autologous blood units were wasted, and there was a 50% reduction in hospital costs. They concluded that the implementation of an algorithm for transfusion strategy changed practice and improved quality of care. The costs for EPO, its administration, and monitoring outside the hospital were offset by the reduction in hospital transfusion costs. However, this may not have a direct correlation to the United States, due to France's national health care system.

Stulberg and Zadzilka (8) evaluated a similar blood management strategy in the U.S, in 2007. (8) It was based on the premise that each patient, surgeon, and operative intervention experiences different risks of requiring transfusion, that those risks are identifiable, and that a plan can be implemented to address them. They recommend avoidance of transfusion triggers, such as the 10/30 (hemoglobin-hematocrit) rule, as healthy patients often can tolerate a Hgb level of 7.0 g/dl or less. They also stressed the importance of clinical assessment of a patient for postural hypotension, tachycardia, and fatigue. Stulberg and Thomas, (9) in a further publication, stated that the most consistent predictor of need for transfusion is a low preoperative Hgb level; and that predicted EBL and patient weight (blood volume) are also useful. (9) In the first year of implementation, autologous donation decreased by 117 units in 226 patients, and the transfusion rate dropped by 20%. The hospital saved more than $50,000 on blood and blood products, with no change in patient-based outcomes of the primary THA and TKA procedures.

Summary

The current literature supports an algorithim, if you will, for postoperative application of blood transfusion, EPO, or iron supplementation in primary TJA (Table 1). Although this algorithm has not been definitely established, it is clear that the evidence supports the development of patient specific strategies (PSS) for perioperative blood management in TJA patients. These algorithms should be surgery specific and even hospital or individual surgeon specific, such that operative blood losses may be predicted. Combining these estimates with an evaluation of a patient's hemoglobin, weight, and medical comorbidities can guide surgeons and their patients to make appropriate decisions with respect to the use of pre-donated autologous blood or erythropoietin, or both. These strategies have proven effective in several studies, with decreased transfusion rates of 20% to 56%, reduction in wasted autologous blood by 50%, and an increase in the use of EPO by 11%. (7,8)

It is important to remember that there are several contraindications to the use of EPO, including severe heart disease, vascular disease, or recent myocardial infarction or stroke. The more common side effects, though still rare, include local skin irritation at the injection site, increased blood pressure, and headaches. Furthermore, the prescribing physician should inquire whether a patient's insurance policy provides coverage for the injections, as this varies by company and by state. Currently, in New York State, Medicare will cover the injections in patients undergoing THA or TKA with Hgb levels of 10 to 13 g/dl.

MRSA Screening

Infection is one of the most dreaded and costly postoperative complications following TJA. Across all surgeries, postoperative infections are associated with substantial morbidity and mortality, doubling the length of hospitalization and increasing the cost of health care in the U.S. by $5 billion to $10 billion annually. (10-14) A recent development in infection prevention has been preoperative screening and treatment for nasal carriage of MRSA. Concerns over community-acquired MRSA began in 1999 when the CDC reported the deaths of four otherwise healthy children who had no risk factors for MRSA infection. (15) It is well documented that certain patient populations are at increased risk of being nasal MRSA carriers. These include patients with recent hospital admission, nursing home residence, indwelling urinary catheters, recent course of antibiotics, being elderly (> 80 years), male, diabetic, or having peripheral vascular disease or varicose ulcers. (16-19) A recent study showed a 24% prevalence of nasal MRSA carriage in patients living in a long-term care setting. (20) However, there has been increased concern recently of nasal MRSA carriage in patients with no risk factors. A 2008 study from the United Kingdom non-selectively screened over 600 patients and found 27 to be colonized with MRSA. Fourteen of the 27 patients had no identifiable risk factors and would not have been picked up by any current selective screening method. (21)

Protocols have been developed to screen and treat high-risk orthopaedic patients who are undergoing elective surgery for nasal MRSA carriage. This has also been done in orthopaedic trauma patients and patients in other surgical fields. There are variations in the protocols, including selective screening of patients with risk factors, nonselective screening, or treating all patients without screening. The treatment regimens are similar and generally include the use of nasal mupirocin ointment 1 day prior to surgery and for 3 to 5 days postoperatively. Triclosan bathing and vancomycin as perioperative prophylaxis are used as adjuncts in some protocols.

Current Evidence

A study performed by Wilcoxa and associates (22) evaluated whether topical perioperative prophylaxis reduced the incidence of MRSA surgical site infections (SSIs). The study evaluated three separate cohorts of orthopaedic patients who underwent elective or acute surgery, in which a metal prosthesis was implanted or internal fixation was applied over consecutive 6-month intervals. Group A received no MRSA prophylaxis, while groups B and C included patients who received perioperative prophylaxis with nasal mupirocin for 5 days, and a shower or bath with 2% triclosan before surgery. All groups received routine peri-operative antibiotics. The data collected were used to calculate SSIs per 1000 operations, to track vancomycin usage, and to obtain point prevalence of nasal MRSA before protocol introduction and at 6-month intervals on four orthopaedic wards and a control medical ward where no protocol was in place.

The investigators found that MRSA SSIs (per 1000 operations) decreased from 23 in period A to 3.3 in period B (p < 0.001) and four in period C (p < 0.001). Of the 11 total MRSA SSI cases that occurred during periods B and C, only one actually received the protocol, and 10 occurred after acute, as opposed to elective, surgery (p < 0.001). The point prevalence of nasal MRSA carriage decreased from 38% before the protocol to 23% immediately after, and 20%, 7%, 10%, and 8% (p < 0.001) at six monthly intervals after the protocol was initiated. The point prevalence of nasal MRSA carriage in the control medicine ward did not change significantly (35%, 20%, 38%, 29%, 30%; p > 0.5). Vancomycin usage, in terms of defined daily doses, declined by 23%; and there was no increase in mupirocin resistance. The protocol was quite effective, but they could not determine the relative contributions of mupirocin and skin disinfection with triclosan. Also, increased infection control precautions by ward staff may have contributed to the decrease in MRSA SSIs. Additionally, at institutions with lower levels of MRSA endemicity (generally less than 5%), it is possible that use of the protocol would be less effective.

The investigators concluded that their study justifies empirical, as opposed to targeted, usage of mupirocin prophylaxis. Further, they estimate that they have prevented approximately 51 orthopaedic MRSA SSIs per year by this intervention. While a formal cost analysis was not performed, large savings are expected given the potential prolonged hospital stay associated with SSIs.

A similar study was conducted, in 2006, in an area with a lower endemic MRSA carriage rate. (23) The study assessed the rates of colonization and infection with MRSA for all elective orthopaedic patients and orthopaedic patients who were treated for a hip fracture in a single hospital over 17 months, before and after a MRSA policy was introduced. The trauma admissions were treated as MRSA carriers until proven otherwise by screening within 24 hours of admission, and all elective admissions were screened for MRSA at the pre-admission clinic. All trauma patients and MRSA positive elective patients received a 5-day course of triclosan and mupirocin and had weekly surveillance swabs. MRSA positive patients were moved to side rooms, managed with barrier nursing, and continued topical treatment, and were treated with 400 mg teicoplanin (glycopeptide similar to vancomycin) intravenously at the induction of anesthesia. The elective patients received the treatment prior to admission, and if MRSA carriage persisted on the day of admission, treatment was continued and surgery delayed if possible. The study reported a MRSA carriage rate of 1.3% for elective admissions and 3.8% for trauma admissions. The incidence of MRSA infection fell from 1.57% of all trauma admissions in the first cohort to 0.69% in the second (p = 0.035). The incidence of MRSA infection reduced by 70% in elective admissions, from 0.56% in the first cohort to 0.17% in the second cohort, but this was not statistically significant (p = 0.06).

Another important finding was that the length of stay (LOS) correlated with significant increased risk of MRSA colonization. Among the trauma patients who remained on the ward for 8 weeks, 25% tested positive for MRSA (p < 0.001). On the elective wards, there was also a strong correlation between LOS and MRSA carriage (r = 0.80, p = 0.03). In the separate analysis of trauma patients, MRSA colonization did not affect the 12-month mortality, compared with the controls (42% versus 39%), but MRSA infected patients had a higher mortality rate, compared with their controls (61% versus 22%; p = 0.017).

In an evaluation of costs, their protocol to screen and treat all trauma and elective patients cost [pounds sterling]83,300 per year ($121,189). They estimated that the protocol prevented 11 MRSA infections over 5 months, equating to the prevention of 26 MRSA infections in 1 year. With their estimated cost to treat one MRSA infection being [pounds sterling]13,972 ($20,000), they could potentially save [pounds sterling]279,972 ($407,318) in 1 year, adhering to their protocol. They concluded that introducing a surveillance and treatment policy is a cost-effective way of reducing MRSA incidence. The more impressive decrease in MRSA SSIs was in the trauma patients, which is likely related to the increase carriage rate seen in this population. Combining the results of the two groups still resulted in significant cost savings, which seems to justify the screening and treatment of the elective patients as well.

Sankar and colleagues, (24) conducted a prospective study to determine the effect of screening for MRSA on reducing hospital-acquired infections and the LOS in patients undergoing total hip and knee replacements. A similar protocol of evaluating two groups pre and post-protocol was applied as in the prior study. The overall incidence of hospital-acquired infections was 8.5% pre-protocol and 3.5% post-protocol (p < 0.05). Four patients pre-protocol had a MRSA infection compared with zero post-protocol (p < 0.05), but only one was a SSI. The LOS decreased from an average of 10.43 days pre-protocol to 9.47 days post-protocol (p = .0049).

They concluded that screening elective orthopaedic patients for MRSA decreased morbidity by reducing hospitalacquired infections and was highly cost-effective. The most notable change was the reduction in the incidence of lower respiratory tract infections, with virtually no difference in SSI. Even without a decrease in SSIs, the program would be considered effective if there was a consistent reduction in LOS.

Several studies have been conducted in other surgical fields evaluating the efficacy of MRSA screening, treatment protocols, and costs. In a study of patients undergoing cardiac surgery, in which a same-day polymerase chain reaction was used for MRSA detection, the investigators found a significant decrease in MRSA SSIs after a screening and treatment protocol was introduced [(1.15% to 0.26% (p < 0.05)]. (25) A randomized, double-blind, placebo-controlled trial evaluating intranasal mupirocin in over 4000 patients who underwent general, gynecologic, neurologic, or cardiothoracic surgery was recently published. The study evaluated the effect of mupirocin on SSI as well as nosocomial infections, secondary to all staphylococcal species, including MRSA but did not evaluate them independently. The investigators did not find a significant decrease in S. aureus SSIs between the placebo and treatment groups, but there was a significant decrease in S. aureus nosocomial infections, from 7.7% in the placebo group to 4.0% in the treatment group (p = 0.02) among patients who were nasal carriers. (26) They found that a screen and treat protocol was more cost-effective than a treat-all protocol, but the savings varied based on efficacy of mupirocin and the prevalence of nasal Staphylococcus carriage. They also demonstrated that at a carriage rate of 20% to 30% and a mupirocin efficacy of 62% or greater, savings could be $1,000,000 per 10,000 patients. (27)

Although these studies demonstrate positive results with MRSA screening and Mupirocin treatment, it is difficult to extrapolate this data directly to orthopaedic patients. It also appears that the cost-effectiveness of the protocol would decrease substantially if MRSA were evaluated independently, given a MRSA prevalence of 5% or less in the general population, instead of evaluating all Staphylococcus species as a group.

Summary

The most impressive results with respect to decreasing SSIs and cost-savings have been demonstrated among populations of patients with high rates of MRSA carriage. However, significant savings can be obtained by preventing only a few infections, due to the high cost of treating an infected total joint replacement. It appears that a screen and treat protocol for all patients admitted to a hospital may be the most effective, as this could create a relative "herd immunity," by decreasing the prevalence of MRSA carriage in the hospital. At the present time, hospitals must make individualized decisions, as there is no definitive support for a specific protocol for the screening and treating of nasal MRSA carriers. Assessing local MRSA rates and individual patient risk factors may contribute to the decision-making process. Large multi-center randomized trials will likely be necessary to gain sufficient power to determine the effectiveness of screening and treatment protocols.

Continuous Passive Motion (CPM)

Range of motion (ROM) after TKA is directly related to patient outcomes, as the ability to perform daily activities depends on the degree of knee motion obtained postoperatively. The ultimate goal is 105[degrees] of flexion or greater, as this allows one to rise from a chair without needing the assistance of their arms. Research pertaining to improving ROM following a TKA has led to modifications in implant design, surgical technique, and postoperative protocols. One of these modifications is the use of continuous passive motion (CPM) as part of postoperative rehabilitation.

Robert Salter introduced the biological concept of CPM in the early 1980s, (28-30) when he demonstrated enhanced cartilage healing and regeneration in rabbit knees with the use of CPM as compared to rest. CPM after TKA was first evaluated by Coutts and coworkers, (31) who concluded that CPM enhanced collagen tissue healing with better fiber orientation, avoided cross-linking and generated better movement restoration. Numerous studies have since shown conflicting results, with the general conclusion being that CPM can lead to improved flexion in the short-term, but demonstrates no benefit at 1-year of follow-up. Why then is the use of CPM so common? Do the early improvements in ROM matter? Does it lead to better patient satisfaction? Can patients achieve goals earlier and be discharged sooner, leading to cost savings?

Current Evidence

A Cochrane review of randomized controlled trials evaluating CPM use for the treatment of patients following TKA was conducted in 2003. (32) Both the experimental and control groups received physical therapy (PT), while the experimental group also received CPM. Fourteen studies met the inclusion criteria, involving a total of 952 patients with a preoperative diagnosis of osteoarthritis (OA) or rheumatoid arthritis (RA).

Overall, CPM combined with PT significantly increased active knee flexion at 2 weeks after TKA by 4.30[degrees]. Statistically significant results were also obtained for LOS in which the CPM and PT group was found to have a significantly shorter time to discharge by 0.69 days.

If the early gains in ROM are directly related to a shorter LOS, then the use of CPM is certainly justified and advisable. This data is promising, but it only reviews 14 articles; and among these, some outcome measures were only comparable between two studies. The conclusion regarding LOS used only six of the articles, with a total of 382 patients. Also, length of CPM treatment in individual studies varied from 18 hours to 2 weeks and daily CPM treatment time varied from 5 to 20 hours per day. Physical therapy protocols also varied between studies. None of the studies assessed functional activities, which may be more relevant than degrees gained in ROM. The reviewers acknowledged these problems and admitted that further study was needed.

A recent study specifically focused on the use of prolonged CPM in patients who had moderate stiffness on discharge home. (33) The study included 60 patients under the age of 80, split into two groups. The patients had a diagnosis of osteoarthritis with equivalent medical comorbidities, and all underwent posterior stabilized TKA with the patella resurfaced. All patients had limited flexion ROM (less than 80[degrees]) of the knee at discharge from the hospital. The protocol included PT for all patients with the use of CPM twice per day for 4 days while in the hospital. After discharge, one group continued CPM twice per day for 2 weeks with PT, while the other group had PT only. Starting on postoperative day 18, both groups continued with postoperative PT. Primary outcomes were functional status, using the WOMAC function score and the Knee Society score and ROM, assessed with a long-arm goniometer. Secondary outcome measures were perceived effect, pain medication usage, satisfaction, adherence to protocols, and duration of PT. The addition of CPM did not show a significant benefit in any of the outcome measures studied at any time-point. However, secondary analysis of patients having less than 68[degrees] of active ROM at discharge showed an added improvement of 11[degrees] in active ROM, with CPM compared to the PT-only group at early follow-up. These differences in ROM disappeared by 6-weeks follow-up. The investigators concluded that prolonged use of CPM, even for patients with relative knee stiffness, was not indicated. The study was limited by the fact that patients applied CPM on their own, leading to possible compliance issues. Furthermore, the PT was not standardized.

Two recent studies evaluated whether the specific method of CPM use could affect ROM. The first was a prospective, randomized trial of 147 patients who had TKA via medial para-patellar approach, in which patients were assigned to one of three postoperative treatment groups. (34) The treatment groups were CPM from 0[degrees] to 40[degrees] and increased by 10[degrees] per day, CPM from 90[degrees] to 50[degrees] (early flexion) and gradually progressed into full extension over a 3-day period, and no CPM. Patients received CPM twice-a-day for 3 hours over a 5-day period, and all patients participated in the same postoperative PT program. Patients were assessed preoperatively, on postoperative day 5, at 3 months, and at 1-year postoperatively. The early flexion group had significantly more range of flexion than both the standard and control groups at day 5, but there was no significant difference between the groups for any other variable tested at any time frame, including LOS. This led the investigators to conclude CPM could not be recommended, as they found no differences in long-term ROM, LOS, and patient satisfaction. However, with respect to LOS and patient satisfaction, there were some problems in study design. Patients did not start ambulation training until postoperative day 3, so that the benefits of increased early flexion, including improved mobility and potentially quicker rehabilitation, and earlier discharge would be difficult to elicit. Furthermore, they did not assess patient satisfaction at day 5, which is the time point that would presumably show a difference given the results. Another limitation is that the average LOS was 8 days, making it difficult to extrapolate to the USA, where the average LOS is 4 to 5 days following a TKA.

The second study was a prospective, randomized trial that compared three inpatient postoperative PT protocols after TKA. (35) The groups were PT alone, PT with 35 minutes of CPM/day, and PT with 2 hours of CPM/day. There were 82 patients total, split between the three groups evenly. The primary outcome measure was active knee flexion at discharge with secondary outcome measures, including the "get up and go test (TUG: Timed Up and Go Test)," WOMAC (Western Ontario MacMaster) questionnaire, and LOS. The TUG test is a timed trial of getting up from a chair with armrests, walking 3 m, turning around, and sitting back in the chair.

They found no significant difference between groups in regard to outcome measures, including knee flexion, knee extension, TUG, WOMAC, or LOS. The investigators concluded that the routine use of CPM could not be recommended. Unfortunately, there were limitations similar to the prior study, in that ambulation was not started until postoperative day 3, and LOS again averaged 8 days. Additionally, CPM was not started until postoperative day 2.

Summary

As several studies, including the Cochrane review, have shown significant early gains in ROM with potential decreases in LOS, it is reasonable to recommend short-term (3 to 5 days), inpatient use of CPM, especially if the machine has already been purchased, as this would incur no additional cost. However, it is clear that further studies evaluating shortterm gains and LOS are needed with large patient populations, as most studies included fewer than 100 patients. Furthermore, it is possible that specific groups would benefit from CPM use, such as patients with rheumatoid arthritis, posttraumatic arthritis, or very elderly patients with medical comorbidities that would make aggressive PT difficult. It is important to note that no study, including those evaluating prolonged use of CPM after discharge from the hospital, has demonstrated a long-term benefit of CPM use.

Conclusion

Preoperative autologous blood donation is largely over utilized, with the use of EPO being under utilized. Surgeons are encouraged to develop patient specific strategies, which have been shown to decrease transfusion rates, reduce wasted autologous blood, and increase the use of EPO. Definitive conclusions regarding MRSA screening for orthopaedic patients cannot be drawn at this time; but due to the significant cost and morbidity associated with a postoperative MRSA infection, we believe that a screen and treat protocol should be considered for all patients being admitted to the hospital for elective or emergent surgery. Further research will help clarify the most appropriate method for minimizing MRSA surgical site infections. Short-term (3 to 5 days), inpatient use of CPM is also recommended at this time. It is low-cost, has minimal risk, and may be a factor in decreasing LOS, potentially leading to significant cost savings. No long-term benefits of CPM use have been established.

Disclosure Statement

None of the authors have a financial or proprietary interest in the subject matter or materials discussed, including, but not limited to, employment, consultancies, stock ownership, honoraria, and paid expert testimony.

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Glassner PJ, Slover JD, Bosco JA 3rd, Zuckerman JD. Blood, bugs, and motion: what do we really know in regard to total joint arthroplasty? Bull NYU Hosp Jt Dis. 2011;69(1):73-80.

Philip J. Glassner, M.D., was a Chief Resident within the Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, and is currently with the Hunterdon Orthopedic Institute and Hunterdon Medical Center, Flemington, New Jersey. James D. Slover, M.D., is Assistant Professor, in the Division of Adult Reconstructive Surgery; Joseph A. Bosco, 3rd, M.D., is Assistant Professor, in the Division of Sports Medicine, and Vice Chair for Clinical Affairs; and Joseph D. Zuckerman, M.D., is Walter A.L. Thompson Professor and Chairman, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York.

Correspondence: Joseph A. Bosco, 3rd, M.D., NYU Hospital for Joint Diseases, 301 East 17th Street, Suite 1402, New York, New York 10003; joseph.bosco@nyumc.org.
Table 1 Current Literature Supported Guidelines for Use
of Autologous Blood in Primary TJA

1. Baseline Hgb [greater than or equal to] 15g/dl
   [right arrow] no intervention.

2. Baseline Hgb 13 to 15g/dl and age < 65 [right arrow]
   no intervention.

3. Baseline Hgb 13 to 15g/dl and age > 65 [right arrow]
   autologous blood pre-donation and EPO both seem to be
   effective (plus iron supplementation), but > 30% of
   autologous units in this group can be expected to be
   wasted.

4. Baseline Hgb 10 to 13g/dl [right arrow] EPO should be
   considered (plus iron supplementation).
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