Tibial Component Revision Arthroplasty Using Porous Tantalum Cone for Symptomatic Progressive Periprosthetic Proximal Tibial Ganglion Cyst about All-Polyethylene Tibia Primary Total Knee Replacement: A Case Report and Review of Literature

Introduction

Intraosseous ganglion cysts are an uncommon variant found in the subchondral bone. We report here the development of an intraosseous ganglion cyst of the proximal tibia in the setting of a prior left total knee arthroplasty (TKA) with an all-polyethylene tibial component.

Case Report

The cyst was diagnosed on routine follow-up radiographs approximately 4 years status post-TKA. Although initially asymptomatic, 1 year later the patient presented with progressive knee pain and ambulation limitations, so revision TKA was indicated. Computed tomography confirmed an osteolytic lesion suggestive of a penetrating ganglion. Given the absence of malrotation or malalignment of the well-fixed femoral component, the decision was made to proceed with tibial revision to stemmed component cemented through a porous tantalum cone. Postoperatively, the patient had complete resolution of pain and instability with 0-120° of stable range of motion, which has persisted to the latest follow-up at over 6 months post-operative, with radiographic resolution of the cyst.

Conclusion

This case demonstrates a ganglion cyst surrounding total knee implants as a possible source of persistent pain following TKA. To our knowledge, this is the first report of such a case. This case demonstrates that refractory painful knee implants secondary to tibial ganglion cysts can be treated successfully with revision arthroplasty.

Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects

PURPOSE

Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects.

METHODS

This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason.

RESULTS

Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components.

CONCLUSION

Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components.

LEVEL OF EVIDENCE

Retrospective cohort study, Level IV.

The effectiveness of prophylactic closed incision negative pressure wound therapy compared to conventional dressings in the prevention of periprosthetic joint infection post hip and knee revision arthroplasty surgery: A systematic review

OBJECTIVE

To evaluate the effectiveness of prophylactic closed incision negative pressure wound therapy (ciNPWT) compared to conventional dressings in the prevention of periprosthetic joint infection (PJI) post hip and knee revision arthroplasty surgery.

METHOD

Five databases (MEDLINE, Embase., Emcare, CINAHL and Scopus) were searched with no date or language limits. Two independent reviewers assessed articles against the inclusion criteria and methodological quality of the 3 included studies. Data was extracted using a customised data tool and included the intervention, study methods and outcomes of interest. A meta-analysis was performed, and results presented in narrative form with forest plots.

FINDINGS

The three studies, one randomized control trial and two quasi-experimental studies, included 136 intervention and 228 control participants (Sample 364). The PJI rate decreased in the ciNPWT cohort compared to the conservative dressing cohort (2 [1.47%] vs 27 [11.84%]). The reoperation rate was lower in the ciNPWT cohort versus the conventional cohort (4 [2.94%] vs 35 [15.35%]). The rate of wound complications was significantly decreased in the ciNPWT cohort compared to the conventional dressing cohort (14 [10.29%] v 85 [37.28), p=<0.001).

CONCLUSION

Prophylactic application of ciNPWT may be effective in reducing wound complications, PJI and reoperation post hip and knee revision arthroplasty surgery. The added cost of ciNPWT may be justified in the reduction of wound complications, PJI and reoperation. Ongoing trials determining if the prophylactic application of ciNPWT post hip and knee revision arthroplasty surgery is beneficial in preventing PJI particularly in high risk patients with additional comorbidities are warranted.

Ruling out underlying infection in 200 presumed aseptic knee and hip revision arthroplasties using a multiplex PCR system

Ruling out an infection in one-stage knee and hip revisions for presumed aseptic failure by conventional tissue cultures takes up to 14 days. Multiplex polymerase chain reaction (mPCR) is a quick test (4-5 h) for detecting pathogens. The purpose of this study was to evaluate the diagnostic accuracy of an automated mPCR of synovial fluid obtained intraoperatively in unsuspected knee and hip revisions. A prospective study was conducted with 200 patients undergoing a one-stage knee or hip revision. Synovial fluid was analyzed with the mPCR Unyvero implant and tissue infection G2 cartridge (U-ITI G2) system and compared to intraoperative tissue cultures. The primary outcome measure was the diagnostic accuracy, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), of the mPCR U-ITI G2 system compared to conventional cultures. In the knee revision group, there were no patients with a positive mPCR in combination with positive cultures. This resulted in a non-calculable sensitivity and PPV. The specificity and NPV in the knee revision group of the mPCR compared to tissue cultures was 96.8% and 96.8%, respectively. In the hip revision group, the sensitivity, specificity, PPV, and NPV of the mPCR compared to tissue cultures was 36.4%, 96.6%, 57.1%, and 92.5%, respectively. Sixteen mismatches occurred between the mPCR and tissue cultures. The mPCR U-ITI G2 system is a quick and reliable synovium fluid test for ruling out infection in presumed aseptic knee and hip revisions with a high NPV compared with tissue cultures, although some mismatches were observed. Periprosthetic tissue cultures are still advised as back-up for false negative and positive mPCR test results.