Implant survivorship and complication rates after total knee arthroplasty with a third-generation cemented system: 5 to 8 years followup

Clinical, Functional, and Midterm Survival Analysis on Sigma Curved Plus Ultracongruent Polyethylene Insert in Primary Total Knee Arthroplasty: A Retrospective Study

BACKGROUND

Posterior-stabilized (PS) total knee arthroplasty (TKA) poses problems such as the need for intercondylar notch bone resection as well as cam and post wear and patella clunk. Owing to its heightened anterior profile, an ultracongruent polyethylene insert prevents the excessive posterior translation of tibia in the case of a deficient or scarified posterior cruciate ligament (PCL). This study aimed to determine whether an ultracongruent insert provides satisfactory clinical and functional outcomes and midterm survival benefits.

METHODS

Based on the reviewed medical records of 200 patients, 240 primary TKA cases involving the use of Sigma Curved Plus (DePuy International, Ltd., Leeds, UK) ultracongruent insert were retrospectively enrolled in this study. Follow-up data were used to evaluate the clinical and radiological outcomes and to conduct a Kaplan-Meier survival analysis.

RESULTS

The mean follow-up duration for 224 knees was 5.8 years (range 5-6.5 years). A revision was made due to infection in two patients and due to periprosthetic fractures in two other patients. The mean knee flexion improved from 101.97° ± 9.43° (range 85°-125°) to 125.75° ± 9.58° (range 100°-140°) at the final follow-up. The mean Knee Society score improved from 43.1 ± 9.76 to 88.3 ± 3.2, and the function score improved from 44.95 ± 7.26 to 90.16 ± 3.71. None of the patients showed radiographic loosening of either insert component, but 22 (5%) patients showed radiolucent lines (<2 mm). The Kaplan-Meier analysis showed that the five-year survival of the insert with an endpoint of revision for any reason was 98.1% (confidence interval, CI, 95.7-99.6%).

CONCLUSION

The Sigma Curved Plus insert showed a low failure rate with good clinical, functional, and midterm survival outcomes in comparison to standard outcomes reported in earlier studies. Further follow-up studies are warranted to determine whether the insert's performance is maintained in the long term.

Cost Analysis, Complications, and Discharge Disposition Associated With Simultaneous vs Staged Bilateral Total Knee Arthroplasty

BACKGROUND

Simultaneous vs staged bilateral total knee arthroplasty (BTKA) has long been debated. The primary objective of this study was to compare actual hospital costs and complication rates in patients undergoing simultaneous BTKA (simBTKA) and staged BTKA (staBTKA) at a single institution.

METHODS

A total joint arthroplasty database from a single hospital was used to identify all patients who underwent primary BTKA from 2013 to 2016 and divided into simultaneous and staged groups. StaBTKA patients were included if both procedures were performed within 1 year by the same surgeon. The combined total hospital cost of both procedures was used, and inpatient rehabilitation (IPR) costs were added for all patients discharged to IPR.

RESULTS

There were 225 simBTKA and 337 staBTKA patients. SimBTKA patients were younger (61 ± 8 vs 66 ± 8 years, P < .001), had lower body mass index (31.3 ± 5.9 vs 34.0 ± 7.2, P < .001), were more predominately male (48% vs 38%, P = .029), and more likely to require IPR as compared with staBTKA patients. There was no difference in total hospital cost for simBTKA as compared with staBTKA ($24,596 ± $5652 vs $24,915 ± $5756, P = .586). Complications were more prevalent in the simBTKA group, including venous thromboembolism (5.4% vs 1.4%, P = .006) and blood transfusions (15.8% vs 6.2%, P < .001).

CONCLUSION

There were higher complication rates with no significant cost savings in actual hospital costs associated with simBTKA, when accounting for the cost of IPR, as compared with staBTKA. The total cost analysis of simBTKA vs staBTKA, using actual cost data, merits further evaluation.

Posterior cruciate-retaining versus posterior-stabilized total knee arthroplasty: a meta-analysis

The objective of this meta-analysis was to compare outcomes of posterior cruciate-retaining and posterior stabilized prostheses. A computerized literature search was conducted to identify randomized controlled trials comparing the clinical outcomes of cruciate-retaining and posterior-stabilized designs. The table of contents of four major Orthopaedic journals and the references section of two arthroplasty text books were reviewed to identify other relevant studies. Ultimately, 1114 patients (1265 knees) were compared. Statistical analysis revealed a significant difference in flexion and range of motion in favor of posterior-stabilized knees, but no difference in complication rates. The clinical importance of this remains unknown. The decision to use one design versus the other should rest with the surgeon's preference and comfort with a particular design.

Midterm survival of a contemporary modular total knee replacement

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1).

The PFC Sigma knee system appears to provide excellent results in the medium term.

Tension controlled ligament balanced total knee arthroplasty: 5-year results of a soft tissue orientated surgical technique

INTRODUCTION

Posterior cruciate ligament (PCL)-retaining prostheses give good outcomes and are commonly used. This retrospective study investigated outcomes from total knee arthroplasty (TKA) using the ligament balancing technique to implant a PCL-retaining knee prosthesis (balanSystrade mark knee system) with either a mobile or a fixed bearing polyethylene inlay.

MATERIALS AND METHODS

A retrospective study was performed on patients treated with TKA at one surgical centre between 1997 and 2001. In this period 182 surgeries were performed. Clinical assessments of the implant used the Knee Society Score (KSS). Subjective assessments used visual analogue scale (VAS) for pain and patient satisfaction. The Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) was used to assess pain, stiffness and function of the knee. Radiographic analysis was performed to determine frontal and sagittal alignment and loosening.

RESULTS

A total of 109 knee implants in 95 patients (26 men; 69 women) were followed up. Seventy-three cases were not available for follow-up due to bad health or death of the patient; 74% of 109 reviewed implants had fixed bearings and 26% had mobile bearings. The mean age at surgery was 72.9 +/- 7.35 years (range 54.7-92.4). The mean KSS was 160 +/- 28.3 points. The KSS was greater for men and was significantly reduced when another disease was present. The type of bearing, surgical approach, and pre-operative alignment for patients affected by varus or valgus gonarthrosis had no significant impact on KSS and ROM. According to VAS the mean scores for pain and satisfaction were 1.48 (0 = no pain) and 9.2 (10 = very satisfied), respectively. The WOMAC mean scores for pain (87.0), stiffness (82.3) and function (78.6) were high (best outcome score of 100). There were no revisions due to aseptic loosening or wear.

CONCLUSION

Total knee arthroplasty performed with a PCL-retaining prosthesis implanted by using a soft tissue oriented surgical technique is a safe procedure and was associated with good results. So far, there were few complications and no need for revision due to aseptic loosening. In addition, most of the patients reported little pain and were satisfied with the outcome. These good outcomes are comparable with other studies reporting on PCL-retaining prostheses.

Midterm results with the PFC Sigma total knee arthroplasty system

We prospectively studied 207 consecutive patients (284 knees) undergoing total knee arthroplasty (June 1996 to December 1997) with a cemented tricompartmental Sigma PFC (DePuy Orthopaedics, Warsaw, Ind) total knee arthroplasty via a standard procedure (median follow-up, 87 months). Cruciate-retaining (272 knees, 96%) and cruciate-substituting (12, 4%) implants were used. There was one revision secondary to a ligament disruption after a fall. No implants were radiographically loose or at risk for loosening. Radiolucencies (none>2 mm or progressive) were shown on anteroposterior (7% of medial tibias) and lateral (17% of posterior femora) radiographs. Knee Society pain scores improved significantly (preoperative median, 20 points; postoperative median, 50 points [P<.001]). The PFC Sigma Knee system has excellent midterm durability.

Distal femur replacement is useful in complex total knee arthroplasty revisions

Revision total knee arthroplasty can be considerably more difficult in cases involving severe bone loss, complete absence of collateral ligaments, and persistent periprosthetic supracondylar femoral fractures. Modular segmental endoprosthetic distal femur replacement is a limb salvage option when other surgical options are unfeasible. The clinical performance of rotating hinge knee prostheses has greatly improved with the evolution of second and third generation designs. The increased freedom of rotation decreases the prosthetic bone stresses and the longevity. While designs have improved, the prostheses still do not match the function and longevity of condylar components with approximately a 90% survivorship at 20 years. The modular endoprosthesis rotating hinge knee prosthesis is useful for total knee arthroplasty revision in patients with inadequate bone stock, ligamentous instability, or difficult supracondylar femur fractures, especially in low demand elderly patients.

LEVEL OF EVIDENCE

Therapeutic study, level V (expert opinion). See Guidelines for Authors for a complete description of levels of evidence.