Exposure for revision knee requires using the previous incision, employing the “quad snip”, the “Banana Peel”, or the tubercle osteotomy. The “quad snip” is a 45-degree incision of the proximal extensor mechanism that helps protect the distal insertion on the tubercle. The “banana peel,” is my exposure of choice and has been used extensively for revision total knee arthroplasty (TKA) for more than 20 years in my community. We retrospectively reviewed use of this technique in a cohort of 100 consecutive patients who underwent tibial-femoral stemmed revision TKA. The technique involves peeling the patella tendon as a sleeve off the tibia, leaving the extensor mechanism intact with a lateral hinge of soft tissue. A quadriceps “snip” must be done proximally to avoid excessive tension. No patient has ever reported disruption of the extensor mechanism or decreased ability to extend the operative knee. With a mean Knee Society score of 176 (range, 95–200). Post-operative motion was 106 degrees. No patient reported pain over the tibial tubercle. The “banana peel” technique for exposing the knee during the revision TKA is a safe method that can be used along with a proximal quadriceps snip and does not violate the extensor mechanism, maintaining continuity of the knee extensors. As a last resort, tibial tubercle osteotomy as described by Whiteside, is preferred for revising porous coated stemmed tibial components and is repaired with cerclage wire or cables. Keep the osteotomy fragment at least 8–10cm long leaving a lateral soft tissue attachment

Systematic surgical exposure during revision total knee arthroplasty is essential for revision surgery. Surgical exposure protects the extensor mechanism, facilitates safe implant removal and allows for accurate reimplantation of components. The pre-operative plan is critical to achieving appropriate exposure in the revision setting. Evaluating the skin and previous incisions will aid in the exposure technique selected. The key to revision total knee arthroplasty is systematic releases. Revision total knees can be exposed with a standard medial parapatellar arthrotomy, a proximal medial tibial peel, and a quad snip. This takes tension off the stiff knee, is easy to repair, and does not require limitation of rehabilitation protocols. The patella need not be everted in the revision surgery. The Banana Peel technique is very helpful for the stiff knee. The tibial tubercle osteotomy can also be utilised in patients with extreme stiffness and can aid in removal of well-fixed tibial stems. Keep the osteotomy long (8–10 cm) and leave a lateral soft tissue bridge. Other techniques such as the quadricepsplasty or V-Y turndown are rarely needed

Surgical exposure during revision total knee arthroplasty is the most essential part of the procedure. An appropriate surgical exposure protects the extensor mechanism, facilitates safe implant removal and allows for accurate reimplantation of components and appropriate soft tissue balancing. The pre-operative plan is critical to achieving appropriate exposure in the revision setting. Evaluating the skin and previous incisions and determining range of motion will aid in deciding which exposure technique is most appropriate. The key to exposure in revision total knee arthroplasty is patience. Approximately 90% of revision total knees can be adequately exposed with a standard medial parapatellar arthrotomy, a proximal medial tibial exposure, complete synovectomy and clearing of the medial and lateral gutters. The patella need not be everted in the revision setting and extreme care must be taken to protect the extensor mechanism. In cases where standard exposure techniques are inadequate or may jeopardise the extensor mechanism, a quadriceps snip may be performed. This takes tension off the stiff knee, is easy to repair and does not require limitation of rehabilitation protocols. The tibial tubercle osteotomy is utilised in patients with extreme stiffness and to aid in removal of well-fixed tibial components. General principles include keeping the osteotomy fragment long (8–10 cm) and leaving a lateral periosteal bridge and soft tissue attachment to aid in repair and healing of the fragment. Other techniques such as the quadricepsplasty or V-Y turndown may be utilised but are rarely needed

Introduction

As the demand for primary total knee arthroplasty (TKA) has been on the rise, so will be the demand for revision knee surgery. Nevertheless, our knowledge on the modes of failure and factors associated with failure of knee revision surgery is considerably lower to that known for primary TKA. To date, this has been mostly based on case series within the literature. Therefore, the aim of this study was to evaluate the survivorship of revision TKA and determine the reasons of failure.

Achievement of adequate exposure in revision total knee arthroplasty is critical as it reduces the surgical time, enhances the ability for both component removal and reconstruction, and avoids devastating complications such as extensor mechanism disruption. However, this can be challenging as prior multiple surgeries and limited mobility contribute to a loss of tissue elasticity, thickened capsular envelope, and peri-articular soft tissue adhesions. A thorough pre-operative assessment of a patient's past surgical history, comorbidities, pre-operative radiographs (i.e. the presence of severe patella baja), and physical examination including range of motion, prior incisions, and soft tissue pliability are useful in determining the appropriate surgical techniques necessary for a successful revision.

A systematic approach to the ankylosed knee is critical. Most techniques are geared towards mobilization of the extensor mechanism to safely displace the patella for component exposure. The initial exposure should consist of a long skin incision, a subperiosteal medial release, and debridement of suprapatellar, medial, and lateral adhesions to the femoral condyles. A lateral capsular release can prove helpful in further mobilization of the extensor mechanism. When performing a medial parapatellar arthrotomy it's important to keep in mind further extensile exposure techniques that may be required. For example, the arthrotomy should not extend proximally into the vastus intermedius or rectus femoris in the event that a quadriceps snip technique is to be used as this can compromise the ability to repair this exposure.

Despite a large exposure and release of adhesions, sometimes the extensor mechanism remains at risk of rupture and adequate visualization cannot be obtained. In this event, extensile exposures such as a quadriceps snip, quadriceps turndown or tibial tubercle osteotomy are considered. The location of the patella often dictates the best exposure option as severe patella baja may not be overcome with a proximally based release. The quadriceps snip is most commonly used and provides improved exposure without the necessity of modifying the patient's post-operative rehabilitation. In addition, it can be extended to a quadriceps turndown which vastly improves visualization, but at the expense of needing to immobilise the knee post-operatively. A tibial tubercle osteotomy can also be used and provides excellent exposure especially in the case of severe patella baja or when removal of a cemented tibial stem is required. It preserves the extensor muscles, but risks include increased post-operative wound drainage due to limited soft tissue coverage, failure of fixation, or fracture of the tibial tubercle fragment or tibial shaft.

Exposure in revision total knee arthroplasty is critical. Fortunately, this can be reliably achieved with a systematic approach to the knee and through the use of several extensile exposures at the surgeon's discretion.

Like all surgery, if you can see it, you can usually get the job done. This is especially true for extracting well-fixed components, as iatrogenic bone loss is a serious consideration regarding the reconstruction challenge. While reasons for revision are varied, several general principles are useful to consider during the pre and peri-operative course.

Pre-operatively, forewarned is forearmed. Certain factors pre-operatively can suggest the degree of operative difficulty regarding exposure. Revisions for stiffness obviously would suggest difficulty with exposure. Revisions in knees with patellar baja are almost always challenging as the patella is difficult to evert. When revising infected knees, an exuberant synovial response can result in beefy, friable synovium that has a volume effect with decreased tissue compliance. Further, the hyperemic friable tissue bleeds easily, even with tourniquet, and is difficult to anticoagulate.

Peri-operatively, the general principles to consider are as follows: 1) Don't rush exposure. Good exposure is the result of a series of deliberate and sequential steps that safely reduce tissue volume and improvement in tissue compliance. These steps include in almost all cases: a. Extend the incision as necessary, there is no call for minimally invasive revision knee surgery; b. Tenolysis of the patellar tendon; c. Clearing of the medial and lateral gutter; d. Clearing of the flexion space; e. Clearing of quadriceps adhesions.

2) Protect the extensor mechanism, above all else. Carefully monitor the insertion of the patellar tendon when beginning to flex the knee. If an avulsion begins, back off flexion and spend more time on clearing of scar tissue, as above. If still unsuccessful, then extensile exposure should be considered, such as a quadriceps snip. Be especially careful when osteolysis is present around the tibial tubercle.

3) The most difficult area to of the knee to expose in revision surgery is the posterior lateral corner, resulting in difficulty in exposing the posterior lateral femur and the posterior corner of the tibial component. Extensile exposures do not necessarily result in complete exposure of these regions. Redoubling efforts to remove scar tissue is often more successful. Bovie dissection of soft tissue on the proximal medial tibia can assist, with extension back to the semimembranosus insertion sometimes being necessary. While adequate exposure can result because of the increased ability to externally rotate the tibia, this exposure can also destabilise the medial side of the knee, sometimes resulting in the need to add constraint. The pros and cons need to be considered on a case-by-case basis.

4) Be judicious in the utilization of extensile exposures, and choose the exposure technique best suited for the situation. If the patellar tendon is normal, consider a simple quadriceps snip. If the knee is particularly stiff or the tibial tubercle or patellar tendon insertion is in jeopardy, then the snip can be extended into a V-Y turndown. If the patellar tendon is contracted resulting in patellar baja, then a tibial tubercle osteotomy (TTO) can be considered. Careful removal of tissue in scar tissue, as above, allows for relative external rotation of the tibia on the femur that translates the patella laterally, reducing the need for TTO. TTO can also be effective when approaching a cemented tibial stem.

Following a careful in-depth preoperative plan for revision TKR, the first surgical step is adequate exposure. The following steps should be considered: 1.) Prior incisions: due to the medially based vascular supply to the skin and superficial tissues about the knee, consideration for use of the most LATERAL incision should be made. 2.) Avoid the use of flaps which may compromise the skin and soft tissue. 3.) Exposure options can be broken down into: PROXIMALLY based techniques: medial parapatella arthrotomy, establish medial and lateral gutters, eversion or subluxation of the patella, extension of arthrotomy proximal, if unable to “mobilise” patella, consider inside out lateral release, if still unable to mobilise: QUAD SNIP, in rare instances, connect lateral release with quad snip resulting in a V-Y quadplasty, may now turn down for excellent exposure.

DISTALLY based techniques: tibial tubercle osteotomy technique described by Whiteside, roughly 8 cm osteotomy segment with distal bevel, osteotomy must be at least 1.5–2 cm thick: too thin and risk of fracture increases, leave lateral soft tissues intact, greenstick” the lateral cortex with eversion of patella, closure with wires.

Obtaining adequate exposure is key to optimising outcomes in revision total knee arthroplasty. Goals of the exposure include protecting the extensor mechanism, safe removal of the components that are in place and implantation of the revision components. Challenges to these goals include prior skin incisions, arthrofibrosis, and patella baja.

Choosing a skin incision is the first important step. The blood supply to the skin is predominantly derived MEDIALLY and thus the most LATERAL skin incision that works for obtaining exposure is selected. If skin flaps are required, they MUST be full thickness as the blood supply to the skin runs deep just over the fascial layer and partial thickness flaps risk skin necrosis. Avoid acute angles between old skin incisions of <60 degrees and skin bridges, if necessary, must be at least 6cm in width.

The work-horse of revision TKA is the medial parapatellar approach. It includes a generous medial release that allows the surgeon to externally rotate and deliver the tibia by pivoting on the extensor mechanism. An anterior synovectomy is then performed to re-establish the medial and lateral gutters followed by re-establishment of the space behind the patellar tendon to free it from the proximal tibia and finally subluxation of the patella (preferable to formal eversion). A lateral release (or peel of the soft tissue off of the lateral side of the patella) is a final step to mobilise the extensor mechanism (if required). After the components are removed, a posterior capsulectomy is performed followed by re-establishment of the flexion space behind the femur further enhances tibial exposure for both bony preparation and revision component implantation.

If the above maneuvers are performed, and exposure is still inadequate, the easiest way to improve exposure is by performing a quadriceps snip. This is an oblique, apical extension of the arthrotomy ACROSS THE PATELLAR TENDON (NOT in the muscle; it is hard to repair if performed in the muscle). It is repaired side to side with no need to alter post-operative physical therapy and heals reliably.

The V-Y Quadricepsplasty is a proximal release of the extensor mechanism; essentially perform by connecting the apical extension of the medial parapatellar arthrotomy with a lateral release across the quadriceps tendon. It is classically indicated for patients with extensor mechanism contracture where the surgeon wishes to lengthen it. It usually results in increased flexion at the expense of an extensor lag and is used rarely in contemporary practice.

Tibial Tubercle Osteotomy is a distal release of the extensor mechanism that is most useful for accessing the canal to remove long-stemmed cemented tibial components. It is a coronal osteotomy made from the medial side of the tubercle that is usually made 5–8 cm in length, tapering from approximately 1cm thick proximally to 5mm distally.

Exposure in revision total knee replacement can be quite challenging due to scar formation from one or many previous incisions. Disruption of the patellar or quadriceps tendon during revision must be avoided at all costs and many surgical maneuvers have been described to permit safe exposure in order to remove the implants during the initial stage of reconstruction. Standard maneuvers include recreation of the medial and lateral gutters, patient dissection to allow the soft tissue to stretch over time and proximal medial exposure of the tibia and release of the semimembranosis tendon insertion.

There are three specialised techniques for exposure during revision total knee replacement: the quadriceps snip as described by Insall, the V-Y quadriceps turndown as described by Coonse and Adams, and the tibial tubercle osteotomy as described by Whiteside.

The quadriceps snip is a proximal lateral extension of the medial arthrotomy used during a standard approach. It is easy to perform and can be used for most revision situations. This is should be the standard first choice for gaining exposure in revision surgery. The V-Y quadriceps turndown is quite extensile and is a combination of a lateral retinacular release connected to the proximal portion of the medial arthrotomy. Although it allows excellent exposure in revision situations, it is associated with extensor weakness and extensor lag. The Whiteside tibial tubercle osteotomy is also a versatile approach. Care should be taken to preserve a lateral periosteal sleeve, and subsequent repair with wire presents the best healing possibility. It is quite elegant in providing access to the proximal tibia to facilitate removal of a well fixed, stemmed tibial component.

Exposure in revision total knee replacement can be quite challenging due to scar formation from one or many previous incisions. Disruption of the patellar or quadriceps tendon during revision must be avoided at all costs and many surgical maneuvers have been described to permit safe exposure in order to remove the implants during the initial stage of reconstruction. Standard manoeuvres include recreation of the medial and lateral gutters, patient dissection to allow the soft tissue to stretch over time and proximal medial exposure of the tibia and release of the semimembranosis tendon insertion.

There are three specialised techniques for exposure during revision total knee replacement: the quadriceps snip as described by Insall, the V-Y quadriceps turndown as described by Coonse and Adams, and the tibial tubercle osteotomy as described by Whiteside.

The quadriceps snip is a proximal lateral extension of the medial arthrotomy used during a standard approach. It is easy to perform and can be used for most revision situations. This is should be the standard first choice for gaining exposure in revision surgery. The V-Y quadriceps turndown is quite extensile and is a combination of a lateral retinacular release connected to the proximal portion of the medial arthrotomy. Although it allows excellent exposure in revision situations, it is associated with extensor weakness and extensor lag. The Whiteside tibial tubercle osteotomy is also a versatile approach. Care should be taken to preserve a lateral periosteal sleeve, and subsequent repair with wire presents the best healing possibility. It is quite elegant in providing access to the proximal tibia to facilitate removal of a well fixed, stemmed tibial component.

Aim

To assess the survival of revision knee replacements at our institution and to identify prognostic factors that predict failure in revision knee surgery.

The aim of this study was to determine the mid-term survival and functional outcomes of the Scorpio Total Stabilised Revision Knee prosthesis.

Sixty seven prostheses were implanted between November 2001 and April 2008. 42 females and 23 males. Average patient age was 67.9 (37-89). Outcomes were assessed with WOMAC (Western Ontario and McMaster Universities Osteoarthritis index), Knee Society Scores, Short Form-8 scores, patient satisfaction and radiological review. Average follow-up was over 3 years (8-93mths) with 95% follow-up.

One patient died post operatively and 4 patients from 18 months to 5 years post-operatively. Average body mass index was 32.9 (21.5- 55.1). 65% (42 patients) of patients operated on had a Body Mass Index of greater than 30. 48 patients were ASA 3 or greater.

Thirteen second stage revision arthroplasties were performed after treatment for infected arthroplasty surgery. Twenty six prostheses were revised for aseptic loosening. Eight prostheses were revised for stiffness and 9 for worn polyethylene inserts. Five prostheses were revised for symptomatic tibio-femoral instability/ dislocation and one for patello-femoral instability. Two revisions were performed for peri-prosthetic fractures and 2 for previously operated tibial plateau fractures.

Seven patients required tibial tubercle osteotomy and seven a rectus snip. Thirty one patients had greater than a 15mm polyethylene insert. The average KSS increased from 49 pre-operatively to 64 at 7.5 years. The average KS function score increased from 21 to 45. 68% (44) of patients had other significant joint involvement which affected daily function. 24% of patients were unsatisfied with the outcome. 89.5% of patients radiographs were assessed for loosening or subsidence. 51% of femoral components and 36% of tibial components had radiosclerotic lines. The surface area of each implant including the stem was measured on antero-posterior and lateral images. The degree of lucency was calculated as a percentage and in mm from the component.

Two prostheses (3%) were revised for deep infection, one (1.5%) for stiffness and one for aseptic loosening (1.5%). Complications included a popliteal artery injury, two superficial wound infections, and one patella tendon avulsion.

Survival rate for revision of prosthesis was 87% at 7.5 years and 90% excluding infection. Success of second stage revision arthroplasty after treatment of infection was 92%.

Then SMILES (Stanmore Modular International Limb Salvage System) was first introduced in 1991 for use as a customized prosthesis in the treatment of malignant and aggressive bone tumours. However, the use of this pros-thesis has been extended to minimal customization, to be used in a situation of salvage surgery for the arthrosplasty, which has already undergone previous revision surgery. Between 1991 and 1997 32 SMILES prostheses were used in thismanner in 30 patients. 28 patients were available for review, all had a minimum of 3 years follow-up. The mean number of previous revision procedures was 2 and 6, average 2.6. There were 11 male and 19 female patients. The mean age at the time of the salvage procedure was 67 years (46 to 86). The mean age of the primary procedure was 57.8 (Range 43–71). The Knee Society score increased from 26 to 68 and the function score increase from 26 and 68 and the function score increased from 27 to 75. Average flexion improved post-operatively from 78 to 88 degrees. 84% of patients stated that they were pleased with the results in terms of pain and mobility.

We conclude that this prosthesis is a satisfactory alternative to complex reconstructions or amputation in the presence of infection, severe bone or soft tissue loss and has rendered acceptable results.

Aims. Joint registries classify all further arthroplasty procedures to a knee with an existing partial arthroplasty as revision surgery, regardless of the actual procedure performed. Relatively minor procedures, including bearing exchanges, are classified in the same way as major operations requiring augments and stems. A new classification system is proposed to acknowledge and describe the detail of these procedures, which has implications for risk, recovery, and health economics. Methods. Classification categories were proposed by a surgical consensus group, then ranked by patients, according to perceived invasiveness and implications for recovery. In round one, 26 revision cases were classified by the consensus group. Results were tested for inter-rater reliability. In round two, four additional cases were added for clarity. Round three repeated the survey one month later, subject to inter- and intrarater reliability testing. In round four, five additional expert partial knee arthroplasty surgeons were asked to classify the 30 cases according to the proposed revision partial knee classification (RPKC) system. Results. Four classes were proposed: PR1, where no bone-implant interfaces are affected; PR2, where surgery does not include conversion to total knee arthroplasty, for example, a second partial arthroplasty to a native compartment; PR3, when a standard primary total knee prosthesis is used; and PR4 when revision components are necessary. Round one resulted in 92% inter-rater agreement (Kendall’s W 0.97; p < 0.005), rising to 93% in round two (Kendall’s W 0.98; p < 0.001). Round three demonstrated 97% agreement (Kendall’s W 0.98; p < 0.001), with high intra-rater reliability (interclass correlation coefficient (ICC) 0.99; 95% confidence interval 0.98 to 0.99). Round four resulted in 80% agreement (Kendall’s W 0.92; p < 0.001). Conclusion. The RPKC system accounts for all procedures which may be appropriate following partial knee arthroplasty. It has been shown to be reliable, repeatable and pragmatic. The implications for patient care and health economics are discussed. Cite this article: Bone Jt Open 2021;2(8):638–645

Introduction. Enhanced pain and rehabilitation protocols have significantly improved patient recovery following primary TKR. Little has been written on how the protocols have affected the revision TKR patient. We report on a matched group of revision and primary TKR patients treated with the identical pain and rehab program. Materials and Methods. 40 aseptic RTKR patients who underwent a full femoral and tibial revision were matched by age, sex, and BMI to a group of patients who underwent a cemented tri-compartmental primary TKR. All revision knees had uncemented stemmed femurs and tibias. All 40 patients had either a metaphyseal sleeve on either the femur or tibia or both. Patients in both groups were treated with an identical post op pain protocol (Spinal anesthetic, local infiltrative analgesia and multimodal oral pain management along with rapid rehabilitation). All patients were mobilized on POD1 and allowed weight bearing as tolerated. Patients were followed for a minimum of 1 year. KSS at 6 weeks and 1 year were recorded for both groups. Results. There was no significant difference in length of stay between the RTKR and the primary TKR (1.2 days versus 1.1 days). Average oral morphine equivalents used during the hospitalization was 38 for the RTKR and 42 for the primary group. There was 1 readmission in each group: GI distress in the RTKR and urinary retention in the primary group. There no were reoperations, wound healing problems, identified thromboembolic events or manipulations under anesthesia in either group. KSS for the RTKR group averaged 87.3 at 6 weeks (range 45 to 99) and 89.1at minimum 1 year (range 52 to100). KSS for the primary group averaged 89.9 (range 71 to 100) at 6 week follow-up and 93.2 (range 54 to 100) at minimum follow-up. Range of motion at final follow up averaged1.2 (0–10) to 114.1 (55–135) for the RTKR group and 1 (0–8) to 121.3 (85–140) for the primary group. Conclusion. Despite more complex surgery in the revision total knee patient, enhanced pain and rehabilitation protocols have enabled the RTKR patient to have a similar recovery and outcome compared to the primary TKR patient. For figures, tables, or references, please contact authors directly

Introduction. One of the main considerations in the revision TKR setting is deciding on the level of constraint to be utilized once the bone defects have been reconstructed. There is a fear that employing a maximally constrained insert could compromise long term results. We report on a consecutive series of full tibial and femoral component revisions all treated with a maximally conforming insert and followed for a minimum of 5 years. Materials and Methods. The study group consisted of 76 consecutive revision TKR in 76 patients where both the femur and the tibia were revised. 4 patients died and 6 were lost to follow up. Final cohort had an average age of 70 years, average BMI of 31 and there were 39 males in the group. Average time to revision was 7 years (range 1–10 years) and the reasons for revision included infection in 28, aseptic loosening 26, osteolysis and poly wear in 9 and 13 other. All were treated with the same revision system and an identical maximally conforming tibial rotating platform insert and followed for an average of 7 years (range 5–14 years). Results. one patient required additional surgery during the study period for a patella fracture. There were no manipulations. Average Knee Society Scores increased from an average of 55 to 89 at final follow up. No implants were loose or at risk of loosening and no knee sustained any mechanical complications related to the insert. Conclusion. Despite fears to the contrary, we did not identify any issues in using a maximally constrained insert in this consecutive group of revision total knee patients. It is unclear if the fact that these inserts were of a rotating platform design is important. In this group of revision TKRs, using the maximal level of constraint did not appear to negatively influence outcome at mid-term follow up

Aims

To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI).

Purpose

Unexpected-positive-intraoperative-cultures (UPIC) in presumed aseptic revision-total-knee-arthroplasties (rTKA) are common, and the clinical significance is not entirely clear. In contrast, in some presumably septic rTKA, an identification of an underlying pathogen was not possible, so called unexpected-negative-intraoperative-cultures (UNIC). The purpose of this study was to evaluate alpha defensin (AD) levels in these patient populations.

Background

As life expectancy increases, the number of octogenarians requiring primary and revision total knee arthroplasty (TKA) is increasing. Recently, primary TKA has become a common treatment option in octogenarians. However, surgeons are still hesitant about performing revision TKA on octogenarians because of concerning about risk- and cost-benefit. The purpose of this study was to investigate postoperative complications and mid-term survival in octogenarians following primary and revision total knee arthroplasty (TKA).

The purpose of this randomized controlled trial is to evaluate the efficacy of using dilute betadine versus sterile saline lavage in aseptic revision total knee (TKA) and hip (THA) arthroplasty to prevent acute postoperative deep periprosthetic joint infection (PJI). Of the 450 patients that were randomized, 5 did not have 90-day follow-up, 9 did not receive the correct treatment, and 4 were excluded for intraoperative findings consistent with PJI. 221 Patients (144 knees and 77 hips) received saline lavage only and 211 (136 knees and 75 hips) received a three-minute dilute betadine lavage (0.35%) prior to wound closure. Patients were observed for the incidence of acute postoperative deep PJI within 90 days of surgery. Statistical analysis was performed using t-tests or Fisher's exact test where appropriate. Power analysis determined that 285 patients per group are needed to detect a reduction in the rate of PJI from 5% to 1% (alpha=0.05, beta=0.20). There were seven PJIs in the saline group and one in the betadine lavage group (3.2% vs. 0.5%, p=0.068). There were no significant differences in any baseline demographics between groups suggesting appropriate randomization. Although we believe the observed difference between treatments is clinically relevant, it was not statistically significant with the sample size enrolled thus far and enrollment is ongoing. Nonetheless, we believe that these data suggests that dilute betadine lavage is a simple method to reduce the rate of acute postoperative PJI in patients undergoing aseptic revision procedures