Revision total knee arthroplasty

Managing Post-Traumatic Arthritis of the Knee with Total Knee Arthroplasty

Post-traumatic arthritis (PTA) of the knee is a complex problem, requiring foresight and careful preoperative planning. Each case of PTA is unique, requiring understanding of the altered anatomy, management of any retained hardware, and also the ability to provide the appropriate stability for each affected knee. Successful treatment of PTA with total knee arthroplasty (TKA) requires the creation of stable and well-balanced joint. TKA for PTA provides comparable improvements in pain and function when compared with primary osteoarthritis, however, these patients are at increased risk of post-operative complications, including instability and infection.

Tips and Tricks to Save You During Revision Total Knee Arthroplasty

The number of revision total knee arthroplasties (TKAs) performed annually continues to rise. This article is a summary of a symposium on revision TKAs presented at the 2023 American Association of Hip and Knee Surgeons annual meeting. It will provide an overview of the surgical tips and tricks for exposure and component removal, use of metaphyseal fixation and stems to manage bone loss and optimize fixation, constraint in TKA, as well as how to manage extensor mechanism disruptions with a synthetic mesh reconstruction. LEVEL OF EVIDENCE: V.

The Effect of Cemented Implants Placed During Initial TKA on Surgical Time and Expenses in Revision TKA

INTRODUCTION

Revision total knee arthroplasty (rTKA) is a complex procedure that often requires the removal of previous implants. There is little information evaluating the difference between removing cemented or noncemented knee prostheses in revision surgeries. The purpose of this study was to determine whether removing cemented or noncemented implants would affect surgical time and expenses incurred during revision procedures.

METHODS

This retrospective cohort study used a single-institution database to identify 300 patients who underwent femoral and tibial implant rTKA from 2016 to 2022 because of mechanical complications (infection cases excluded). Radiographs and surgical reports were used to confirm whether the fixation technique was cemented (N = 243) or noncemented (N = 57). The primary outcomes were surgical time and surgery costs. Secondary outcomes included readmission rates, revision implants used, stem usage, and insurance type.

RESULTS

The average surgical time was 121 minutes for noncemented and 128 minutes for cemented procedures (P = 0.118). The 90-day readmission rates for each group were similar at 7.00% for the cemented cohort and 8.77% for the noncemented cohort (P = 0.643). For patients with Medicare Advantage, the respective surgery costs were $1,966 for noncemented and $1,968 for cemented TKA (P = 0.988). For patients with commercial insurance, the respective surgery costs were $4,854 for noncemented and $5,660 for cemented TKA (P = 0.330).

CONCLUSION

Primary knee fixation type, cemented or noncemented, did not appear to influence the surgical duration or surgical costs of both-implant revision knee surgery indicated for mechanical complications.

Maintenance of the joint line and posterior condylar offset are the most notable variables for successful outcomes of revision total knee arthroplasty

INTRODUCTION

Controversy regarding which variables should be prioritized for better outcomes in revision total knee arthroplasty (RTKA) exists. This study aimed to comprehensively analyze the variables affecting RTKA outcomes.

MATERIALS AND METHODS

We retrospectively identified 87 RTKAs in 82 patients who were performed between March 2014 and February 2020. Range of motion (ROM), including flexion contracture (FC) and further flexion (FF), was analyzed according to the covariates. The covariates included mode of failure, joint line position, anteroposterior (AP) position, rotational alignment of the femoral component, and patellofemoral alignment. The differences between the final follow-up values of each RTKA variable and those of the native knee were evaluated. The clinical outcomes were evaluated.

RESULTS

No significant differences were observed between the joint line positions of the RTKA and native knees. The patellar and AP positions of the femoral component were restored to pre-TKA values. The femoral component had an external rotation of 2.78° compared with the native knee. In multivariable stepwise regression analysis, restoration of the adductor tubercle joint line and posterior condylar offset (PCO) were significant variables affecting ROM. Septic RTKA (33 knees) resulted in poor FF outcomes (p = 0.030) and Western Ontario and McMaster Universities Osteoarthritis Index stiffness (WOMAC S) scores (p < 0.001), compared with aseptic RTKA (54 knees).

CONCLUSIONS

Restoration of the joint line position and PCO are crucial factors for improved ROM in RTKA. Joint line elevation in RTKA resulted in worse ROM than joint line lowering. In addition, RTKA due to septic failure had inferior ROM and WOMAC S scores compared with RTKA due to aseptic failure.

LEVEL OF EVIDENCE

Level III, cohort study.

Outcomes in revision knee arthroplasty: Preventing reoperation for infection Keynote lecture - BASK annual congress 2023

Revision total knee arthroplasty (TKA) patients have a lower survival rate and lower post-surgical outcomes compared to primary TKA patients. Infection and aseptic loosening are the most common reasons for revision and re-revision TKAs, with infection accounting for nearly half of re-revision cases. To prevent infection, patient optimization addressing obesity, diabetes, malnutrition, and smoking cessation is crucial. Advancements in irrigation solutions, antibiotic-impregnated bone fillers, bacteriophage therapy, and electrochemical therapy hold promise for preventing infection. Technical strategies such as obtaining sufficient component fixation, joint line restoration, and using robot assistance may improve revision TKA outcomes. As the burden of revision TKA continues to rise, substantial efforts remain for mitigating future revision TKAs and their associated complications.

A Reliable Surgical Approach to Revision Total Knee Arthroplasty

Backgroud

The surgical exposure obtained in revision total knee arthroplasty should facilitate the utilisation of instrumentation and implants, including adjuncts such as stemmed prostheses, bone allograft, and artificial augments. We have previously identified within this cohort of revision total knee arthroplasty patients a high satisfaction rate of 93.5% at a mean 6.5 years of follow-up and a high level of postoperative function. We, therefore, seek to describe in detail the operative technique and perioperative care and report the early postoperative complications.

Methods

We report on the surgical approach, closure technique, and postoperative care used by the senior author for revision total knee arthroplasty procedures. The patient demographics, intraoperative details, and postoperative outcomes are also reported. We aim to provide a clear description of the intraoperative technique and postoperative outcome, facilitating adoption or comparison with other surgeons or techniques. Patient inclusion criteria were revision total knee arthroplasty performed by the senior author using the PFC (Depuy) prosthesis at John Flynn Private Hospital with a minimum of 2-year postoperative follow-up. A retrospective chart review was combined with a structured telephone assessment questionnaire to assess outcomes.

Results

A total of 202 revision total knee arthroplasties were available for follow-up in 185 patients. The mean 1-year postoperative range of motion was 110°. Key features of surgical approach include incision planning, soft-tissue plane development, parapatellar scar debridement, safe removal of implants, management of bone defects, and closure technique. The overall 90-day complication rate was 9%, including 4.4% requiring manipulation under anaesthesia and 3% superficial surgical site infections (1 patient requiring intravenous antibiotics).

Conclusions

We suggest that the described technique is reproducible and reliable. It rarely requires modification and facilitates successful postoperative outcomes with a low complication rate. The adoption of this surgical technique allows surgeons to approach complex knee arthroplasty with confidence in the appropriate exposure of anatomy, facilitating subsequent steps in their arthroplasty procedures.

The Effect of Joint Line Elevation on Patient-Reported Outcomes After Contemporary Revision Total Knee Arthroplasty

BACKGROUND

Joint line elevation in revision total knee arthroplasty (rTKA) is considered a risk factor for inferior outcomes, engendering a dogmatic protocol of joint line restoration. However, this precedent is based on historical data using rudimentary revision systems and unvalidated outcome measures. This study's purpose was to evaluate the effect of joint line height elevation on validated patient-reported outcome measures (PROMs) using modern revision implants.

METHODS

A total of 327 rTKAs performed at a single institution were reviewed. Surgical technique prioritized flexion-extension gap balancing and accepted joint line elevation if necessary to achieve a balanced flexion space. Radiographic measurements included changes in joint line height (from preoperative and calculated "intended" anatomic/native) and change in posterior condylar offset. Prospectively collected PROMs were evaluated using multivariate regression.

RESULTS

The mean joint line elevation from preoperative and "intended" to postoperative joint line was 4.9 ± 5.7 mm and 7.2 ± 6.6 mm, respectively. The mean increase in posterior condylar offset was 1.0 ± 4.6 mm. Patients within ±5 mm of preoperative joint line height were 3.88× more likely to achieve the substantial clinical benefit for Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .004). An increase from intended joint line height >5 mm was not associated with differences in any other PROMs (P ≥ .165).

CONCLUSIONS

In contemporary rTKA, recreating the joint line within 5 mm of preoperative improves knee-specific health outcomes. These data support approximating native joint line height as a viable technique to optimize flexion gap balance and subsequent patient outcomes in rTKA.

LEVEL OF EVIDENCE

Level III retrospective cohort study.

Metaphyseal Stem Extension Improves Tibial Stability in Cementless Total Knee Arthroplasty

BACKGROUND

The goal was to determine if the addition of a metaphyseal stem extension limits micromotion of a cementless tibial component during cyclic loading in primary total knee arthroplasty. The hypothesis tested was that the use of a 50-mm stem extension on a cementless tibial component would limit motion compared with an identical cementless component without a stem extension.

METHODS

The study used 3 variations of a tibial component from the same total knee arthroplasty system. Group 1 consisted of a cementless tibial component without a stem extension. Group 2 used the same cementless component as group 1, but with the addition of a short 50-mm stem. Group 3 consisted of a cemented tibial component without a stem extension to serve as a "control" (gold standard). The tibial specimens were implanted into a synthetic bone model and tested using a physiological medial-lateral 60/40 load distribution for 5000 cycles.

RESULTS

The results demonstrated a significant decrease in motion at the anterior region of the cementless stem extension (group 2) components compared with the cementless with no stem extension (group 1). The cementless with stem extension (group 2) demonstrated similar results at all cycles to the cemented (group 3) components at the anterior region.

CONCLUSION

The addition of a short metaphyseal stem (50mm) to a keel plus 4-peg tibial component design provides a significant reduction in micromotion during cyclic loading of a cementless tibial baseplate in a synthetic foam bone model, similar to a cemented implant.

Intravenous Tranexamic Acid Safely and Effectively Reduces Transfusion Rates in Revision Total Knee Arthroplasties

BACKGROUND

The efficacy and safety of tranexamic acid (TXA) in primary total knee arthroplasty (TKA) have been well established. However, there have been limited data for revision TKAs. The primary aim was to assess the impact of intravenous TXA on transfusion rates and symptomatic venous thromboembolic events (VTEs) in a large revision TKA cohort with or without intravenous TXA utilization.

METHODS

A retrospective review of revision TKAs performed from 2005 to 2014 was performed, identifying 2,951 procedures (2,219 patients), in which TXA was utilized in 1,144 procedures (39%). The mean age was 65 years with 52% female patients in the TXA revision group and 67 years with 52% female patients in the non-TXA revision group. Transfusion rates and symptomatic VTEs were the primary outcomes assessed. Comparisons were performed between cohorts, utilizing a unique propensity model to mitigate bias, on the basis of TXA use and subsequently for aseptic or septic revision etiology.

RESULTS

Significant reductions in transfusion rates with use of TXA were identified in revision TKAs overall (13% compared with 39%; p < 0.001 [adjusted relative risk, 1.7]), including revisions for both aseptic etiology (6% with TXA compared with 28% without TXA; p < 0.001) and septic etiology (31% with TXA compared with 54% without TXA; p < 0.001). The risk of a postoperative symptomatic VTE was not significantly different (adjusted p = 0.63) with use of TXA at 11 events (1.0%) compared with 24 events (1.3%) in the non-TXA group).

CONCLUSIONS

Intravenous TXA significantly reduced transfusion rates in revision TKAs by approximately twofold, including cohorts revised for aseptic and septic etiologies. There was a very low rate of VTEs (1.2%) with no significant difference in the number of VTEs between groups after adjusting risk utilizing propensity modeling.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Extraction of total knee arthroplasty intramedullary stem extensions

Intramedullary stem extensions will need to be extracted during total knee arthroplasty (TKA) revisions, especially repeated ones. These stems have various designs and lengths, can be straight or offset, cemented (partially or totally) or cementless, smooth or rough. This diversity adds to the difficult of extracting them, which the surgeon must anticipate before starting the revision procedure. Porous metaphyseal metal components (cones, sleeves) are being used increasingly during revision TKA. They pose specific extraction challenges and complicate the extraction of the stems with which they are often associated. The maneuvers used during extraction have a direct impact on the subsequent joint reconstruction methods. These procedures are always long and difficult, with an increased risk of bone-related complications (perforation, fracture) or infection. They must always be carried out at specialized centers by experienced surgeons. The reasons for re-revision are the same as those for TKA revision, mainly aseptic loosening, instability and infection-only the latter requires that all components be removed. The local conditions are often unfavorable: epiphyseal-metaphyseal bone defect, thin cortices, osteoporosis, and in some cases, stiffness. The type of implant to extract and its characteristics must be identified beforehand in case special instruments are needed. An imaging workup is done to specify the relationship of the stem with bone, quality of its fixation, bone lesions and gaps between stem and bone, knowing that extraction is harder when the gaps are smaller. A combination of extended radiolucent lines, purely metaphyseal fixation, and a thin smooth stem may mean that intramedullary extraction is feasible. The extensor mechanism must be released to achieve sufficient exposure. If a tibial tubercle osteotomy is needed, it must be sized to match the extraction. After disassembly of femoral and tibial components-which can be challenging-the epiphyseal components must be released. High performance instruments for cement extraction and metal cutting are essential. Other than simple cases (loosened or partially fixed implants), intramedullary extraction can be dangerous especially when the stem extension is well-fixed, whether cemented or not. A diaphyseal window may be sufficient, but in most cases, an extended osteotomy is needed. This includes detaching the tibial tubercle at the tibia. At the femur, this may require an anterior midline window, an anterior extended ostéotomy or an anterolateral oblique distal femoral osteotomy with fibrous hinge. The extraction of metaphyseal porous components is difficult. Their connection with the bone must be broken - which can be long and risky - before the associated stem is removed. While it is easier to extract when the stem can be removed first, it is not always feasible. Reconstruction depends intimately on the methods used to extract the existing implants. Any diaphyseal discontinuity must be bridged (long stem or plate). The extent of the resulting bone defect after extraction drives the revision methods, which are simplified by using porous metaphyseal metal components and shorter stems when possible.

Proximal tibial replacement in revision knee arthroplasty for non-oncologic indications

Proximal tibial metaphyseal bone loss compromises the alignment and fixation of components during revision total knee arthroplasty. In massive, segmental defects with loss of collateral ligamentous support and lack of bone to support the use of prosthetic augments or metaphyseal cones or sleeves, a hinged proximal tibial replacement or a so-called “megaprosthesis” should be available. While proximal tibial replacement is the reconstructive method of choice in the setting of bone tumor resection, applications in non-oncologic joint arthroplasty are rare and may offer an opportunity for limb salvage in dire clinical scenarios with massive proximal tibial bone loss. This report reviews 6 cases of proximal tibial replacement.

Revision total knee arthroplasty (TKA): mid-term outcomes and bone loss/quality evaluation and treatment

Background

Revision total knee arthroplasty (rTKA) is a demanding procedure, with a high complication and failure rate and a high rate of bone losses and poor bone quality. Different classifications for bone losses have been proposed, but they do not consider bone quality, which may affect implant fixation. The aim of this study is to describe the outcomes of a consecutive series of rTKA. Furthermore, a modified bone loss classification will be proposed based also on bone quality. Finally, the association between radiolucent line (RLL) development and different risk factors will be evaluated.

Methods

All the patients who underwent rTKA between 2008 and 2016 in the same institution were included. rTKAs were performed by the same surgeon according to the three-step technique. Bone losses were classified according to the proposed classification, including bone quality evaluation. The Knee Scoring System (KSS), the Hospital for Special Surgery Knee Score (HSS), and the SF-12 were used for the clinical evaluation. Radiological evaluation was performed according to the Knee Society Roentgenographic Evaluation System. Different possible risk factors (i.e., gender, age, amount of bone losses) associated to RLL development were identified, and this association was evaluated using logistic regression.

Results

Fifty-one patients (53 knees) were included (60.8% female, average age 71.5 years). The average follow-up was 56.6 months (range 24–182). The most frequent cause of failure was aseptic loosening (41.5%). 18.9% of the cases demonstrated poor bone quality. Bone losses were treated according to the proposed algorithm. In all the cases, there was a significant improvement in all the scores (P < 0.05). The average post-operative range of motion was 110.5° (SD 10.7). At the radiological evaluation, all the implants resulted well aligned, with 15.1% of non-progressive RLL. There were 2 failures, with a cumulative survivorship of 92.1% at the last follow-up (SD 5.3%). At the logistic regression, none of the evaluated variables resulted associated to RLL development.

Conclusion

rTKA is a demanding procedure, and adequate treatment of bone losses is mandatory to achieve good results. However, also bone quality should be taken into consideration when approaching bone losses, and the proposed classification may need surgeons after an adequate validation.

Level of evidence

Level IV

Preoperative Estimated Glomerular Filtration Rate Is a Marker for Postoperative Complications Following Revision Total Knee Arthroplasty

BACKGROUND

Revision total knee arthroplasty (TKA) is an increasingly common procedure, but complication rates are higher than for primary TKA. A requirement for dialysis has been shown to predict postoperative complications in this patient population, but the impact of less severe, but clinically significant, renal impairment has not been addressed.

METHODS

A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program Database. All patients who underwent revision TKA between 2007 and 2014 were identified and the estimated glomerular filtration rate (eGFR) was calculated for each patient. The incidence and predictors of adverse events following surgery were evaluated with univariate and multivariate analyses where appropriate.

RESULTS

Patients with lower eGFRs (<60 mL/min) were found to develop more postoperative complications, including return to the operating room, postoperative pneumonia, urinary tract infection, sepsis, septic shock, and death. Decreased renal function was shown to be an independent risk factor for development of renal insufficiency, renal failure, and extended length of stay.

CONCLUSION

Patients with decreased eGFRs have greater risk for many postoperative complications, but this increased risk is generally related to the greater number of comorbidities in this patient population. When controlling for these comorbidities, poor renal function is an independent risk factor for extended length of stay as well as postoperative renal injury and renal failure, and patients may benefit from perioperative measures to limit this excess renal risk.

Use of Closed Incisional Negative Pressure Wound Therapy After Revision Total Hip and Knee Arthroplasty in Patients at High Risk for Infection: A Prospective, Randomized Clinical Trial

BACKGROUND

Continuous wound drainage after arthroplasty can lead to the development of a periprosthetic joint infection. Closed incisional negative pressure wound therapy (ciNPWT) has been reported to help alleviate drainage and other wound complications. The purpose of this prospective randomized controlled trial is to compare the use of ciNPWT with our standard of care dressing in revision arthroplasty patients who were at high risk to develop wound complications.

METHODS

A total of 160 patients undergoing elective revision arthroplasty were prospectively randomized to receive either ciNPWT or a silver-impregnated occlusive dressing after surgery in a single institution. Patients were included if they had at least 1 risk factor for developing wound complication(s): wound complication, readmission, and reoperation rates were collected at 2, 4, and 12 weeks postoperatively.

RESULTS

The postoperative wound complication rate was significantly higher in the control cohort compared to the ciNPWT cohort (19 [23.8%] vs 8 [10.1%], P = .022). There was no significant difference between the control and ciNPWT cohorts in terms of readmissions (19 [23.8%] vs 16 [20.3%], P = .595). Reoperation rate was higher in controls compared to ciNPWT patients (10 [12.5%] vs 2 [2.5%], P = .017). After adjusting for the history of a prior periprosthetic joint infection and inflammatory arthritis, the ciNPWT cohort had a significantly decreased wound complication rate (odds ratio 0.28, 95% confidence interval 0.11-0.68).

CONCLUSION

ciNPWT may decrease the rate of postoperative wound complications in patients who are at an increased risk of such wound issues after revision arthroplasty.

Efficacy of Revision Surgery for the Treatment of Stiffness After Total Knee Arthroplasty: A Systematic Review

BACKGROUND

Knee stiffness following total knee arthroplasty (TKA) may cause pain and reduced functionality, contributing to unsatisfactory surgical outcomes. Revision surgery remains a possible treatment for refractory postoperative stiffness. However, the efficacy of the procedure has not been systematically evaluated.

METHODS

A systematic review of the literature was performed to identify studies that reported on outcomes for patients who underwent revision surgery for postoperative stiffness after TKA.

RESULTS

Ten studies (including 485 knees) were reviewed. The most common etiologies of stiffness requiring revision TKA were component malposition, malalignment, overstuffing, aseptic loosening, arthrofibrosis, patella baja, and heterotopic ossification. Of 9 studies reviewing range of motion outcomes after revision TKA, 7 studies documented significant improvement and 2 found trends toward improvement. Seven of 8 studies documenting Knee Society knee scores and 7 of 9 studies documenting functional scores found improvement after revision TKA. All studies reporting on pain found improvement at final follow-up after revision TKA.

CONCLUSION

Revision TKA results in increased range of motion, improved functionality, and reduced pain in most patients who require surgery for stiffness. The present literature is inadequate to predict which patients will achieve adequate outcomes from revision TKA based on the specific etiology of their stiffness, although identification of the etiology may help in surgical planning. Surgeons performing revision TKA should counsel patients on the risks and benefits of undergoing revision surgery, with the understanding that outcomes for well-selected patients are generally favorable.

Rotating hinge prosthesis for complex revision total knee arthroplasty: A review of the literature

INTRODUCTION

The rotating hinge prosthesis was originally used and designed as a primary total knee arthroplasty implant, but was hampered due to poor outcomes and catastrophic failures. Newer rotating hinge implants can be utilized in complex revision total knee arthroplasties when appropriately indicated, but their outcome data is very difficult to interpret due to the strict and varied indications for use and subsequently small number of procedures performed. The goal of this review is to evaluate the current evidence on large cohort, rotating hinge knee prostheses used in the revision setting, in order to provide a clearer understanding of the indications, outcomes and complications.

METHODS

The PubMed database was utilized to search the available literature regarding "hinged knee," or "rotating hinge" devices. Exclusion criteria included papers focusing on primary arthroplasty, revision for oncologic issues, one-stage revision for infection or studies with less than fifty cases.

RESULTS

Review of 115 abstracts after initial search, led to ten studies in the literature that met our inclusion and exclusion criteria. The data shows that rotating hinge knee implants have good survivorship ranging from 51% to 92.5% at 10 years post-operatively. Complication rates range from 9.2% to 63% with infection and aseptic loosening as the most common complications.

CONCLUSION

Rotating hinge knee prostheses are most commonly indicated for infection, aseptic loosening, instability and bone loss in the literature. They have good outcome scores and survivorship, but continue to have high complication and revision rates. The implant is a good option when utilized appropriately for patients that are not candidates for less constrained devices.

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty

PURPOSE

The aim of this study was to quantify the medial soft tissue contributions to stability following constrained condylar (CC) total knee arthroplasty (TKA) and determine whether a medial reconstruction could restore stability to a soft tissue-deficient, CC-TKA knee.

METHODS

Eight cadaveric knees were mounted in a robotic system and tested at 0°, 30°, 60°, and 90° of flexion with ±50 N anterior-posterior force, ±8 Nm varus-valgus, and ±5 Nm internal-external torque. The deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) were transected and their relative contributions to stabilising the applied loads were quantified. After complete medial soft tissue transection, a reconstruction using a semitendinosus tendon graft was performed, and the effect on kinematic behaviour under equivocal conditions was measured.

RESULTS

In the CC-TKA knee, the sMCL was the major medial restraint in anterior drawer, internal-external, and valgus rotation. No significant differences were found between the rotational laxities of the reconstructed knee to the pre-deficient state for the arc of motion examined. The relative contribution of the reconstruction was higher in valgus rotation at 60° than the sMCL; otherwise, the contribution of the reconstruction was similar to that of the sMCL.

CONCLUSION

There is contention whether a CC-TKA can function with medial deficiency or more constraint is required. This work has shown that a CC-TKA may not provide enough stability with an absent sMCL. However, in such cases, combining the CC-TKA with a medial soft tissue reconstruction may be considered as an alternative to a hinged implant.

Soft Tissue Reconstruction and Flap Coverage for Revision Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty is a successful operation for treatment of arthritis. However, devastating wound complications and infections can compromise the knee joint, particularly in revision situations.

METHODS

Soft tissue loss associated with poor wound healing and multiple operations can necessitate the need for reconstruction for wound closure and protection of the prosthesis.

RESULTS

Coverage options range from simple closure methods to complex reconstruction, including delayed primary closure, healing by secondary intention, vacuum-assisted closure, skin grafting, local flap coverage, and distant microsurgical tissue transfer.

CONCLUSION

Understanding the advantages and pitfalls of each reconstructive option helps to guide treatment and avoid repeated operations and potentially devastating consequences such as knee arthrodesis or amputation.

The difficult primary total knee arthroplasty: a review

Primary total knee arthroplasty (TKA) is a reliable procedure with reproducible long-term results. Nevertheless, there are conditions related to the type of patient or local conditions of the knee that can make it a difficult procedure. The most common scenarios that make it difficult are discussed in this review. These include patients with many previous operations and incisions, and those with severe coronal deformities, genu recurvatum, a stiff knee, extra-articular deformities and those who have previously undergone osteotomy around the knee and those with chronic dislocation of the patella. Each condition is analysed according to the characteristics of the patient, the pre-operative planning and the reported outcomes. When approaching the difficult primary TKA surgeons should use a systematic approach, which begins with the review of the existing literature for each specific clinical situation.

Metaphyseal bone loss in revision knee arthroplasty

The etiology of bone loss encountered during revision total knee arthroplasty (TKA) is often multifactorial and can include stress shielding, osteolysis, osteonecrosis, infection, mechanical loss due to a grossly loose implant, and iatrogenic loss at the time of implant resection. Selection of the reconstructive technique(s) to manage bone deficiency is determined by the location and magnitude of bone loss, ligament integrity, surgeon experience, and patient factors including the potential for additional revision, functional demand, and comorbidities. Smaller, contained defects are reliably managed with bone graft, cement augmented with screw fixation, or modular augments. Large metaphyseal defects require more extensive reconstruction such as impaction bone grafting with or without mesh augmentation, prosthetic augmentation, use of bulk structural allografts, or use of metaphyseal cones or sleeves. While each technique has advantages and disadvantages, the most optimal method for reconstruction of large metaphyseal bone defects during revision TKA is not clearly established.

Dealing with the predicted increase in demand for revision total knee arthroplasty: challenges, risks and opportunities

Worldwide rates of primary and revision total knee arthroplasty (TKA) are rising due to increased longevity of the population and the burden of osteoarthritis. Revision TKA is a technically demanding procedure generating outcomes which are reported to be inferior to those of primary knee arthroplasty, and with a higher risk of complication. Overall, the rate of revision after primary arthroplasty is low, but the number of patients currently living with a TKA suggests a large potential revision healthcare burden. Many patients are now outliving their prosthesis, and consideration must be given to how we are to provide the necessary capacity to meet the rising demand for revision surgery and how to maximise patient outcomes. The purpose of this review was to examine the epidemiology of, and risk factors for, revision knee arthroplasty, and to discuss factors that may enhance patient outcomes.

What is the level of evidence substantiating the Medicare local coverage determinations?

Total joint arthroplasty (TJA) accounts for large expenditures of Medicare resources. Recovery audit contractors (RACs) utilize Local Coverage Determinations (LCDs) documents to retrospectively assess the medical necessity of performed procedures. The Florida LCD requires 3 months of documented unsuccessful nonoperative care prior to TJA. The purpose of our study was to evaluate the applicability and quality of the evidence cited in the Florida LCD for patients undergoing TJA. Applicability was assessed by evaluating the efficacy of nonoperative treatment in candidates for TJA. There were 23 citations, of which 11 mentioned nonoperative treatment and only 5 provided references. No citations provided Level I or II evidence substantiating the effectiveness of 3 months of nonoperative treatment in patients who would otherwise be candidates for TJA.

Outcomes of revision surgery for cubital tunnel syndrome

PURPOSE

To compare both validated patient-rated and objective outcomes of patients following revision cubital tunnel surgery to a similar group of patients who underwent primary surgery.

METHODS

This case-control investigation enrolled 56 patients treated surgically for cubital tunnel syndrome (28 revision cases, 28 primary controls) at a tertiary center. Patients with a minimum of 2 years of follow-up were eligible. All patients completed an in-office study evaluation. Revision participants represented 55% of potential patients in our practice and controls (treated only with primary surgery) were chosen at random from our practice to reach a 1:1 case to control ratio. Preoperative McGowan grading was confirmed similar between the groups. Outcome measures included validated patient outcome questionnaires (Patient-Rated Elbow Evaluation, Levine-Katz questionnaire), symptoms, and physical examination findings. Statistical analyses were conducted to compare the patient groups.

RESULTS

Despite 79% of revision patients reporting symptomatic improvement, revision patients reported worse outcomes on all measured standardized questionnaires compared with primary patients. The Levine-Katz questionnaire indicated mild residual symptoms in the primary group (1.6) versus moderate remaining symptoms following revision surgery (2.3). The Patient-Rated Elbow Evaluation also indicated superior results for the control group (9 ± 10) compared with the revision group (32 ± 22). Revision patients had a higher frequency of constant symptoms, elevated 2-point discrimination, and diminished pinch strength. McGowan grading improved after 25% of revision surgeries versus 64% of primary surgeries, and 21% of revision patients had deterioration of their McGowan grade.

CONCLUSIONS

Subjective and objective outcomes of revision patients in this cohort were inferior to outcomes of similar patients following primary surgery. Revision surgery can be offered in the setting of persistent or recurrent symptoms that are unexplained by an alternative diagnosis, but patients should be counseled that complete resolution of symptoms is unlikely.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Decreased blood transfusion following revision total knee arthroplasty using tranexamic acid

Tranexamic acid (TXA) has been used successfully in primary total knee arthroplasty (TKA) to minimize blood loss and transfusions. The purpose of this study is to determine its efficacy in patients undergoing revision TKA. In a retrospective review of 111 patients (68 control and 43 TXA), treatment patients receiving a single intravenous TXA dose of 10mg/kg required less transfusions (P=0.03) and less total blood units consumed than controls (P=0.03). When stratified by type of revision, treatment patients undergoing femoral and tibial component revision had lower transfusion rates than the controls (P=0.03). Given the drawbacks of allogenic blood transfusion, we highly recommend the use of TXA in revision TKA, especially when both components are being revised.

Anterior distal femoral osteotomy for removal of long femoral stems in revision knee arthroplasty

Osteotomies of the proximal femur and proximal tibia in revision arthroplasty are well described while guidelines for distal femoral osteotomy are limited. Femoral stems are used with increasing frequency for fixation of revision components in knee arthroplasty and their removal is technically challenging particularly in the setting of infection. We describe a technique of anterior distal femoral osteotomy for revision knee arthroplasty to assist with removal of well-fixed long stemmed cemented or porous femoral components, as well as debridement of infection while preserving bone stock and soft tissue attachments.

The influence of leg length difference on clinical outcome after revision TKA

BACKGROUND

The purpose of this paper was to document the incidence of leg length changes after revision total knee arthroplasty (TKA) and its effect on clinical outcome.

METHODS

Leg length difference (LLD) was prospectively measured in 85 patients using digital standing full leg radiography before and after revision TKA. Additionally the patient's subjective perception of LLD was assessed postoperatively. Linear regression models were used to study the correlation between each of these parameters and the clinical outcome after 1 year. Clinical outcome was evaluated by means of the Knee Society Score (KSS).

RESULTS

Revision TKA resulted on average in an increased leg length of 5.3 mm. Sixty-five legs (76%) were lengthened with the procedure, 17 (20%) were shortened and three (4%) remained of identical length. Increased leg length after revision was positively correlated with clinical outcome at 3 months (Spearman r=0.22, p=0.044) and 1 year (Spearman r=0.26, p=0.027). The evidence for this correlation remained after correction for age, gender and diagnosis (p=0.012). The most important contributors to improved clinical outcome scores were improved pain score (Spearman r=0.19, p=0.09) and increased stability (Spearman r=0.13, p=0.24), rather than range of motion (Spearman r=-0.02, p=0.85).

CONCLUSIONS

The results from our work indicate that revision TKA tends to lengthen the leg by approximately 5mm. Contrary to what might be expected, leg lengthening after revision TKA is correlated with improved clinical outcome.

LEVEL OF EVIDENCE

Level 2b.

Predisposing factors which are relevant for the clinical outcome after revision total knee arthroplasty

PURPOSE

The objective of this study was to investigate the outcome of revision total knee arthroplasty (TKA) in relation to the cause of index failure, the characteristics of the index procedure, and the elapsed time between index TKA and revision.

METHODS

A retrospective review based on a prospective database was performed on 146 consecutive revision TKA's. Variables tested were the cause of index failure; the elapsed time between the index and revision procedure; patient age at time of revision; partial or total revision of the implants; the performance of a tibial tubercle osteotomy; the presence of radiolucent lines; postoperative patellar tracking; and coronal plane alignment. Outcomes were measured with the Knee Society Knee Score (KS), Function Score (FS), and X-ray evaluation.

RESULTS

Mean KS improved from 27.6 (SD 21.6) to 71.5 (SD 24.2) after revision (P < 0.0001), mean FS from 27.5 (SD 22.7) to 53.3 (SD27.7), P < 0.0001. Overall survival rate was 90% at 5 years and 85% at 10 and 14 years. The cause of index failure had no significant influence on any of the outcome parameters. Significantly, better outcomes were noted for partial revisions and for revisions in older patients. Early revisions (<2 years) were mostly performed for infection and instability, whereas late revisions (>2 years) were mostly performed for polyethylene wear and loosening. The survival rate for late revisions was significantly better than for early revisions (P = 0.002).

CONCLUSION

Revision TKA leads to a significant reduction in symptoms and improvement in function. The worst results can be expected for early revisions in young patients. Revision TKA is a demanding procedure with variable results and should therefore be performed by experienced surgeons.

LEVEL OF EVIDENCE

Therapeutic study-Level IV.

Antibacterial activity of bone allografts: comparison of a new vancomycin-tethered allograft with allograft loaded with adsorbed vancomycin

Bacterial contamination of bone allograft is a significant complication of orthopedic surgery. To address this issue, we have engineered a method for covalently modifying bone allograft tissue with the antibiotic vancomycin. The goal of this investigation was to compare the biocidal properties of this new allograft material with those of vancomycin physisorbed onto graft material. The duration of antibiotic release from the vancomycin-modified allograft matrix was determined, and no elution was observed. In contrast, the adsorbed antibiotic showed a peak elution at 24h that then decreased over several days. We next used an Staphylococcus aureus disk diffusion assay to measure the activity of the eluted vancomycin. Again we found that no active antibiotic was eluted from the covalently modified allograft. Similarly, when the vancomycin-modified allograft morsel was used in the assay, no measurable elution was observed; amounts of antibiotic released from the adsorbed samples inhibited S. aureus growth for 4-7 days. Probably the most telling property of the allograft was that after 2 weeks, the tethered allograft was able to resist bacterial colonization. Unlike the elution system in which vancomycin was depleted over the course of days-weeks, the antibiotic on the allograft was stably bound even after 300 days, while its biocidal activity remained undiminished for 60 days. This finding was in stark contrast to the antibiotic impregnated allograft, which was readily colonized by bacteria. Finally we chose to evaluate three indicators of cell function: expression of a key transcription factor, expression of selected transcripts, and assessment of cell morphology. Since the tethered antibiotic appeared to have little or no effect on any of these activities, it was concluded that the stable, tethered antibiotic prevented bacterial infection while not modifying bone cell function.

Risk of subsequent revision after primary and revision total joint arthroplasty

BACKGROUND

Revision is technically more demanding than primary total joint arthroplasty (TJA) and requires more extensive use of resources. Understanding the relative risk of rerevision and risk factors can help identify patients at high risk who may require closer postsurgical care.

OBJECTIVES/PURPOSES

We therefore evaluated the risk of subsequent revision after primary and revision TJA in the elderly (65 years or older) patient population and identified corresponding patient risk factors.

PATIENTS AND METHODS

Using the 5% Medicare claims data set (1997-2006), we identified a total of 35,746 patients undergoing primary THA and 72,913 undergoing primary TKA; of these, 1205 who had THAs and 1599 who had TKAs underwent initial revision surgery. The rerevision rate after primary and revision TJAs was analyzed by the Kaplan-Meier method. The relative risk of revision surgery for primary and revision TJAs was compared using hazard ratio analysis.

RESULTS

The 5-year survival probabilities were 95.9%, 97.2%, 81.0%, and 87.4% for primary THA and TKA and revision THA and TKA, respectively. Patients with revision arthroplasty were five to six times more likely to undergo rerevision (adjusted relative risk, 4.89 for THA; 5.71 for TKA) compared with patients with primary arthroplasty. Age and comorbidities were associated with initial revision after primary THA and TKA.

CONCLUSIONS

Patients should undergo stringent preoperative screening for preexisting health conditions and careful patient management and followup postoperatively so as to minimize the risk of an initial revision, which otherwise could lead to a significantly greater likelihood of subsequent rerevisions.