Distal Femoral Arthroplasty for the Treatment of Periprosthetic Fractures After Total Knee Arthroplasty

Periprosthetic fractures after total knee arthroplasty present substantial challenge if associated with poor bone stock, fracture comminution, and loose or damaged components. Revision total knee arthroplasty with distal femoral arthroplasty is often necessary in these injuries. We reviewed 20 patients (22 knees) with a mean age of 69.5 years who underwent revision with distal femoral arthroplasty fracture. Patients were followed for an average of 58.6 months. At the latest follow-up, the mean Knee Society knee and functional score were 82.8 and 40, and the Short Form 36 mean physical functioning and mental functioning scores were 55.8 and 65.6, respectively. There were 10 postoperative complications with 5 patients requiring additional surgery. Distal femoral arthroplasty seems to be a viable option for complex periprosthetic femoral fractures after total knee arthroplasty. However, considering the relatively high rate of complications, this procedure should be reserved for patients where alternative treatments are not possible.     

Postoperative Femoral Component Rotation and Femoral Anteversion after Total Knee Arthroplasty in Patients with Distal Femoral Deformity

We asked whether total knee arthroplasty (TKA) in patients with distal femoral deformity (DFD) would change femoral component rotation (FCR) and investigated the correlation between DFD and femoral anteversion (FA). 75 patients were divided into two groups according to the preoperative posterior condylar angle (PCA); group A without DFD (PCA < 7°), group B with DFD (PCA > 7°). We evaluated the different angles on the CT scan: (1) PCA, (2) angle between the line which is perpendicular to the Whiteside's line and PCL (WLP), and (3) FA. The mean FCRs were external rotation of 0.21° + 2.75° in group A and internal rotation of 4.48° + 2.51° in group B (P = 0.001). The mean preoperative and postoperative FAs were similar in group A but were significantly different in group B (P = 0.035). DFD resulted in excessive internal rotation of the femoral component. There was a secondary decrease in FA in patients with DFD.     

Failure of the Tibial Insert in a Rotating Hinge Total Knee Arthroplasty

There has been a steady increase in the number of revision total knee arthroplasties being performed in the United States. Hinge knee prostheses are used predominantly in complex primary or revision arthroplasties, often as salvage procedures. Significant improvement of the articulation between the rotating hinge mechanism and tibial component has decreased the stresses that contributed to earlier failures in previous generation designs. Two cases of fracture of the tibial metal post in the rotating hinge of a revision total knee arthroplasty were evaluated and treated at our institution within a 1-month period. We present our experience with this construct failure and subsequent patient management.     

Rotating Hinge Implants for Complex Primary and Revision Total Knee Arthroplasty

Background

Contemporary rotating hinge knee (RHK) prosthesis has shown improved survival rates over earlier generations. However, reports of high complication and mechanical failure rates highlight the need for more clinical outcome data in the complex primary and revision setting. The purpose of this study is to report our results of using a contemporary rotating hinge for complex primary and revision total knee arthroplasty.

Survivorship of Metaphyseal Sleeves in Revision Total Knee Arthroplasty

Background

Metaphyseal fixation has promising early results in providing component stability and fixation in revision total knee arthroplasty (TKA). However, there are limited studies on midterm results of metaphyseal sleeves. We analyzed complications, rerevisions, and survivorship free of revision for aseptic loosening of metaphyseal sleeves in revision TKA.

Primary Versus Secondary Distal Femoral Arthroplasty for Treatment of Total Knee Arthroplasty Periprosthetic Femur Fractures

Current methods of fixing periprosthetic fractures after total knee arthroplasty (TKA) are variable, and include open reduction and internal fixation (ORIF) via plating, retrograde nailing, or revision using standard revision TKA components or a distal femoral arthroplasty (DFA). The purpose of this study is to compare patients who failed plating techniques requiring subsequent revision to DFA to patients who underwent primary DFA. Of the 13 patients (9.2%) who failed primary ORIF, causes included nonunion (53.8%), infection (30.8%), loosening (7.7%), and refracture (7.7%). There were significantly more surgical procedures for ORIF revision to DFA compared to primary DFA. Complications for patients who underwent primary reconstruction with DFAs included extensor mechanism disruption (8.3%), infection (5.6%), and dislocation (2.8%). Primary reconstruction via ORIF is beneficial for preserving bone stock, but primary DFA may be preferred in osteopenic patients, or those at high risk for nonunion.     

Femoral Bow Predicts Postoperative Malalignment in Revision Total Knee Arthroplasty

Diaphyseal bowing may compromise axial alignment in revision total knee arthroplasty (TKA). 277 patients undergoing revision TKA were evaluated for coronal bowing and hip–knee–ankle (HKA) axis. The mean femoral bow was 1.52° ± 0.18° varus (− 10.1° to + 8.4°). The mean tibial bow was 1.25° ± 0.13° valgus (− 5.9° to + 10°). HKA axis averaged 3.08° ± 0.35° varus preoperatively compared to 0.86° ± 0.25° varus postoperatively. Inter-rater and intra-rater reliability was high. Femoral bow greater than 4° significantly correlated with postoperative HKA axis malalignment (r = 0.402, P = 0.008). 39.7% of patients deviated 3° or greater from a neutral mechanical axis with a significant difference in femoral bow (0.94° ± 0.31°, P = 0.003). Diaphyseal bowing clearly has an important effect on postoperative limb alignment in revision TKA.     

Coccidioidomycosis Infection of a Total Knee Arthroplasty in a Nonendemic Region

Fungal prosthetic joint infections are rare and difficult to treat. There is an ongoing discussion about the type and duration of antifungal treatment and the necessity of prosthesis removal. We report the first European case of an infected total knee arthroplasty with Coccidioides immitis. Treatment consisted of lifelong treatment with oral fluconazole at a dose of 400 mg/d, without total knee arthroplasty removal. After 6 months, the initial complaints of pain and swelling were completely resolved. This case report clearly states that a travel history and culturing for fungi are helpful in patients with persisting complaints after joint arthroplasty.     

Total Knee Arthroplasty After Failed Distal Femoral Varus Osteotomy Using Selectively Stemmed Posterior Stabilized Components

The purpose of this study was to evaluate the outcomes of patients treated with total knee arthroplasty (TKA) for progression of arthritis after distal femoral varus osteotomy. Twenty-two consecutive distal femoral varus osteotomies converted to TKA were reviewed at a mean follow-up of 5 years (range, 2-14 years). Stemmed femoral or tibial components were used in 5 knees with poor bone quality, while the remaining 17 knees were treated with unstemmed components. The mean Knee Society knee and function scores in surviving knees were 91 points (range, 67-100 points) and 64 points (range, 50-70 points) respectively at final follow-up. Two patients underwent revision arthroplasty for polyethylene wear and component loosening at 8 and 11 years after the index arthroplasty, respectively. Standard components provide satisfactory stability in TKA after distal femoral varus osteotomy after appropriate ligamentous balancing, without the need for stemmed or highly constrained components in the majority of patients.     

Knee Arthroscopy After Total Knee Arthroplasty: Not a Benign Procedure

BackgroundOutcomes of knee arthroscopy (KA) after total knee arthroplasty (TKA) have been limited to small case series with short-term follow-up. The purpose of this study is to report the outcomes of patients who undergo a KA after a TKA using a large longitudinal database.MethodsThe PearlDiver Medicare database was queried for patients who underwent a KA procedure after a TKA on the ipsilateral extremity. A randomly selected control group was created by matching controls to cases in a 3:1 ratio based on age, gender, year of procedure, and Elixhauser Comorbidity Index. Revision for infection and all-cause revision were used as end points.ResultsA total of192 TKA patients who underwent a subsequent KA (TKA + KA group) were compared to 571 TKA patients who did not have a subsequent KA (TKA − KA group). The incidence of revision for infection was 6.3% in the TKA + KA group compared to 2.2% in the TKA − KA group (odds ratio, 2.87; P = .009). The incidence of all-cause revision was 18.8% in the TKA + KA group compared to 5.1% in the TKA − KA group (odds ratio, 4.34; P < .001).ConclusionKA after TKA was associated with increased infection-related and all-cause revision. The association between KA and subsequent infection requires further investigation.     

A Systematic Review of Clinical Outcomes and Survivorship After Total Knee Arthroplasty With a Contemporary Modular Knee System

A systematic review appraising the clinical performance and safety of the primary SIGMA modular knee system (DePuy-Synthes, Warsaw, Ind.) found 5 registry reports and 53 journal publications reporting survivorship or postoperative increase in Knee Society scores on 241 632 primary SIGMA knee arthroplasties. Pooled data from national joint registries and clinical studies on primary SIGMA knee survivorship were comparable. Both were higher than for all other knees in 5 national joint registries up to 5 years. Compared with pooled data from 2 independent systematic reviews of primary non-SIGMA knees, the SIGMA system provided comparable postoperative changes in Knee Society knee score and a nonsignificant trend of higher postoperative changes in Knee Society function score. This finding suggests that this knee system provides excellent durable results.     

Re-revision Knee Arthroplasty in a Tertiary Center: Infection and Multiple Previous Surgeries Were Associated With Poor Early Clinical and Functional Outcomes

BackgroundThe incidence of re-revision knee arthroplasty (re-revision KA) is increasing and associated with high complication and failure rates. The aim of this study was to investigate re-revision rates, complications, and patient-reported outcomes following re-revision KA and factors associated with poor outcome.MethodsThis was a retrospective cohort study of 206 patients (250 knees) undergoing re-revision KA at a major revision center from 2015 to 2018. The mean follow-up was 26 months (range, 0 to 61) and mean age at re-revision KA was 69 years (range, 31 to 91 years). The main indications for surgery were prosthetic joint infection (PJI) (n = 171/250, 68.4%) and aseptic loosening (n = 25/250, 10.0%). We compared re-revision rates, joint function, and complications for aseptic and infective indications. Logistic regressions were performed to identify risk factors for further reoperation.ResultsThe estimated re-revision rates at 2 years were 28.7% (95% confidence interval [CI]: 22.7-35.9) and at 4 years were 42.0% (95% CI: 32.8-52.6). Mean Oxford Knee Score was 26 points (range, 1 to 48). Mean EuroQoL-5D-5L utility was 0.539 (range, -0.511 to 1.000). Multivariable analyses demonstrated that PJI (Odds Ratio [OR] 2.39, 95% CI 1.06-5.40, P = .036), greater number of previous surgeries (OR 1.18, 95% CI 1.04-1.33, P = .008), and higher Elixhauser score (OR 1.06, 95% CI 1.01-1.13, P = .045) were independently associated to further surgery.ConclusionRe-revision KA carried a high risk of early failure. Multiple revised joints and patients with more comorbidities had worse function. Patients undergoing re-revision KA for PJI should be counseled to expect higher failure rates and complications than patients who have aseptic indications.     

A Comparison of Variable Angle Versus Fixed Angle Distal Femoral Resection in Primary Total Knee Arthroplasty

This study assessed whether using a variable distal valgus resection angle improved post-operative coronal lower limb alignment in total knee arthroplasty (TKA). Two groups were compared: Fixed (n = 124), where a fixed distal valgus resection angle of 7° was used; Variable (n = 87), where the resection angle was adjusted to the measured femoral mechanical anatomical (FMA) angle of the patient. FMA and mechanical femoro-tibial (MFT) angles were measured on pre-operative and post-operative hip-knee-ankle radiographs. 85% of patients in the Variable group had a post-operative MFT angle within 0° ± 3°compared to 69% in the Fixed group (P = 0.006). The use of a fixed distal femoral resection angle for all patients is not appropriate. Setting the resection to an individual patient’s FMA angle can significantly improve the post-operative MFT angle.     

Distal Femoral Rotation Correlates With Proximal Tibial Joint Line Obliquity: A Consideration for Kinematic Total Knee Arthroplasty

Background

We hypothesized that there is a correlation between the distal femoral rotation and proximal tibial joint line obliquity in nonarthritic knees. This has significance for kinematic knee arthroplasty, in which the target knee alignment desired approximates the knee before disease.

Acute Kidney Injury Following Failed Total Hip and Knee Arthroplasty

Background

Acute kidney injury (AKI) can complicate primary total joint arthroplasty (TJA) of the hip and knee, although the incidence of AKI following revision TJA including prosthetic joint infection (PJI) is poorly defined. We assessed the incidence and risk factors for AKI following revision TJA including surgical treatment of PJI with placement of an antibiotic-loaded cement (ALC) spacer.

Retrieval Analysis of Polyethylene Components in Rotating Hinge Knee Arthroplasty Implants

BackgroundThis study examined a cohort of retrieved rotating hinge (RH) total knee arthroplasty implants of four different designs with emphasis on the surface damage observed on the polyethylene components. Our purpose was to determine if differences in polyethylene damage existed among the designs, and if those differences could be explained by differences in design characteristics.Materials and MethodsSeventy-two RH implants from four manufacturers (DePuy LPS/SROM, Zimmer NexGen, Stryker Howmedica MRH, and Biomet Finn-OSS) removed at the time of revision performed between 2002 and 2017 were identified in our institutional retrieval registry. Damage to the surfaces of the polyethylene was assessed using a subjective grading system and evaluated in multiple zones. Design characteristics that were evaluated included the following: location of the dwell point on the polyethylene component, posterior position of the axle, and amount of hyperextension and rotation allowed by the implant.ResultsThere were no differences in total damage scores between the four implant groups (P = .45). The Stryker Howmedica MRH group showed the least backside wear of all implants but significantly more articular-sided wear compared with two of the other three groups. All implants except NexGen showed increased total damage scores in implants revised for mechanical (vs nonmechanical) reasons and in implants with a longer duration of implantation.ConclusionNo single implant design emerged as superior in terms of minimizing polyethylene wear damage. Polyethylene damage existed in various locations but was not different in severity across designs, suggesting that there is no clear superior RH design that minimizes overall articular surface wear compared with other designs.     

1.5-Stage Exchange Arthroplasty for Total Knee Arthroplasty Periprosthetic Joint Infections

BackgroundPeriprosthetic joint infection (PJI) in total knee arthroplasty (TKA) is a challenging problem. The purpose of this study was to outline a novel technique to treat TKA PJI. We define 1.5-stage exchange arthroplasty as placing an articulating spacer with the intent to last for a prolonged time.MethodsA retrospective review was performed from 2007 to 2019 to evaluate patients treated with 1.5-stage exchange arthroplasty for TKA PJI. Inclusion criteria included: articulating knee spacer(s) remaining in situ for 12 months and the patient deferring a second-stage reimplantation because the patient had acceptable function with the spacer (28 knees) or not being a surgical candidate (three knees). Thirty-one knees were included with a mean age of 63 years, mean BMI 34.4 kg/m², 12 were female, with a mean clinical follow-up of 2.7 years. Cobalt-chrome femoral and polyethylene tibial components were used. We evaluated progression to second-stage reimplantation, reinfection, and radiographic outcomes.ResultsAt a mean follow-up of 2.7 years, 25 initial spacers were in situ (81%). Five knees retained their spacer(s) for some time (mean 1.5 years) and then underwent a second-stage reimplantation; one of the five had progressive radiolucent lines but no evidence of component migration. Three knees (10%) had PJI reoccurrence. Four had progressive radiolucent lines, but there was no evidence of component migration in any knees.Conclusions1.5-stage exchange arthroplasty may be a reasonable method to treat TKA PJI. At a mean follow-up of 2.7 years, there was an acceptable rate of infection recurrence and implant durability.     

Knee Arthrodesis Is a Durable Option for the Salvage of Infected Total Knee Arthroplasty

BackgroundKnee arthrodesis (KA) and above-knee amputation (AKA) have been used for salvage of failed total knee arthroplasty (TKA) after periprosthetic joint infection (PJI). However, few studies have assessed the outcomes of KA after TKA PJI, as it remains an uncommon procedure. We investigated rates of AKA, control of infection, and ambulatory status after KA for TKA PJI treatment.MethodsThis was a retrospective and single-surgeon series of 51 failed TKAs due to PJI treated with two-stage KA between 2000 and 2016 with a minimum of 2-year follow-up. Patient demographics, comorbidities, surgical history, radiographic data, and outcomes of KA treatment were recorded.ResultsInfection was successfully controlled in 48 of 51 patients (94.1%); of these, 24 knees (50.0%) required no reoperation subsequent to the index KA, whereas the remaining 24 (50.0%) patients required a median of 1 additional operation. Nonunion, malunion, or delayed union was noted in 10 patients (19.6%). Of the 48 patients who were successfully treated with KA, 41 patients (85.4%) remained ambulatory after KA and 9 of these patients (18.8%) did not require assistive devices. Three of 51 patients (5.9%) progressed to AKA after KA.ConclusionPatients undergoing KA for TKA PJI had high rates of infection control and preservation of ambulatory status, with low rates of progression to AKA in our study.Level of EvidenceLevel IV—case series.     

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.