Abstract:This study showed optimal survivorship of the NexGen LPS, associated with a significant improvement in overall outcomes at a minimum follow-up of 15 years.
“…3 Implant-specific survivorship plot at follow-up of 16 years, demonstrating cases that were revised for an implant related cause. Three cases of instability and one non-specific pain rate than Lutzner et al [28] and Panni et al [34] but compatible with registry data [15,16]. Of the 10 revision surgeries, 50% of revision could conceivably be attributed to the implant itself including three patients revised for instability and 2 revised due to non-specific pain.…”
Section: Follow-up Time (Years)supporting
confidence: 80%
“…In fact, the mean index age at the time of TKA was 63 years and this seems to be an issue in several other reports [27][28][29]. To our knowledge there are few studies that have than 10 years of followup of NexGen Posterior Stabilized TKA system [34,35].…”
Purpose Studying long-term survivorship and functional outcomes for specific prostheses is critical for elucidating areas in need of design improvement. This study reports the long-term of the NexGen Posterior Stabilized (PS) Total Knee implant (TKA) (Zimmer Biomet, Warsaw IN) Performed by a single surgeon. Methods Data from patients treated with the NexGen PS TKA between January 2003 and December 2005 with a minimal follow-up of 15 years was collected from a prospectively collected database. Survivorship rates and Oxford Knee Scores (OKS) were obtained for those patients available for follow-up. Results Ninety-five patients met the inclusion criteria during the study period. OKS was available for 44 (46%) patients. Ten patients required revision surgery (10.52%). Implant-specific survivorship of all cases that were reviewed was 98%. Survivorship of implants in patients that we were able to reach, or deceased patients was 93%. The average Oxford Knee Score was 39.1 (14-48. SD ± 7.70) with 48 being the maximal score. Conclusion Despite some concerns about durability of this implant, good longevity and function was demonstrated. At a minimum of 15 years follow-up in this cohort. Given these results design features of this system should be considered for future generations of implants.
“…3 Implant-specific survivorship plot at follow-up of 16 years, demonstrating cases that were revised for an implant related cause. Three cases of instability and one non-specific pain rate than Lutzner et al [28] and Panni et al [34] but compatible with registry data [15,16]. Of the 10 revision surgeries, 50% of revision could conceivably be attributed to the implant itself including three patients revised for instability and 2 revised due to non-specific pain.…”
Section: Follow-up Time (Years)supporting
confidence: 80%
“…In fact, the mean index age at the time of TKA was 63 years and this seems to be an issue in several other reports [27][28][29]. To our knowledge there are few studies that have than 10 years of followup of NexGen Posterior Stabilized TKA system [34,35].…”
Purpose Studying long-term survivorship and functional outcomes for specific prostheses is critical for elucidating areas in need of design improvement. This study reports the long-term of the NexGen Posterior Stabilized (PS) Total Knee implant (TKA) (Zimmer Biomet, Warsaw IN) Performed by a single surgeon. Methods Data from patients treated with the NexGen PS TKA between January 2003 and December 2005 with a minimal follow-up of 15 years was collected from a prospectively collected database. Survivorship rates and Oxford Knee Scores (OKS) were obtained for those patients available for follow-up. Results Ninety-five patients met the inclusion criteria during the study period. OKS was available for 44 (46%) patients. Ten patients required revision surgery (10.52%). Implant-specific survivorship of all cases that were reviewed was 98%. Survivorship of implants in patients that we were able to reach, or deceased patients was 93%. The average Oxford Knee Score was 39.1 (14-48. SD ± 7.70) with 48 being the maximal score. Conclusion Despite some concerns about durability of this implant, good longevity and function was demonstrated. At a minimum of 15 years follow-up in this cohort. Given these results design features of this system should be considered for future generations of implants.
“…Pooled analysis of data derived from case series reported at exactly 15 years or 20 years showed an all-cause construct survivorship of 96·3% (95% CI 95·7–96·9) at 15 years and 94·8% (92·5–97·1) at 20 years. Figure 2A shows a forest plot for the meta-analysis of data on TKRs derived from case series at 15 years and 20 years.Figure 2Forest plot of estimates for reported survival of knee replacements from case series11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32(A) Total knee replacements at 15 years and 20 years. (B) Unicondylar knee replacements at 15 years, 20 years, and 25 years.…”
Summary
Background
Knee replacements are the mainstay of treatment for end-stage osteoarthritis and are effective. Given time, all knee replacements will fail and knowing when this failure might happen is important. We aimed to establish how long a knee replacement lasts.
Methods
In this systematic review and meta-analysis, we searched MEDLINE and Embase for case series and cohort studies published from database inception until July 21, 2018. Articles reporting 15 year or greater survival of primary total knee replacement (TKR), unicondylar knee replacement (UKR), and patellofemoral replacements in patients with osteoarthritis were included. Articles that reviewed specifically complex primary surgeries or revisions were excluded. Survival and implant data were extracted, with all-cause survival of the knee replacement construct being the primary outcome. We also reviewed national joint replacement registry reports and extracted the data to be analysed separately. In the meta-analysis, we weighted each series and calculated a pooled survival estimate for each data source at 15 years, 20 years, and 25 years, using a fixed-effects model. This study is registered with PROSPERO, number CRD42018105188.
Findings
From 4363 references found by our initial search, we identified 33 case series in 30 eligible articles, which reported all-cause survival for 6490 TKRs (26 case series) and 742 UKRs (seven case series). No case series reporting on patellofemoral replacements met our inclusion criteria, and no case series reported 25 year survival for TKR. The estimated 25 year survival for UKR (based on one case series) was 72·0% (95% CI 58·0–95·0). Registries contributed 299 291 TKRs (47 series) and 7714 UKRs (five series). The pooled registry 25 year survival of TKRs (14 registries) was 82·3% (95% CI 81·3–83·2) and of UKRs (four registries) was 69·8% (67·6–72·1).
Interpretation
Our pooled registry data, which we believe to be more accurate than the case series data, shows that approximately 82% of TKRs last 25 years and 70% of UKRs last 25 years. These findings will be of use to patients and health-care providers; further information is required to predict exactly how long specific knee replacements will last.
Funding
The National Joint Registry for England, Wales, Northern Ireland, and Isle of Man and the Royal College of Surgeons of England.
“…Several recent studies have reported that malalignment after TKA is not a determinant factor for the survival of prosthesis. 22 23) Therefore, the concept that the mechanical axis should correspond to a safety zone defined as within 3° of neutral limb alignment is being challenged. 24 25) Furthermore, some studies have suggested a change of paradigm in definitive, ideal coronal alignment and implant positioning for TKA.…”
BackgroundAchieving neutral limb alignment during total knee arthroplasty (TKA) has been considered an important determinant in the long-term prosthesis survival. The purpose of this study was to evaluate the association between the immediate postoperative mechanical alignment of the lower limb and the rate of revision TKA by comparing an acceptable mechanical axis group (within ± 3° from neutral alignment) and an outlier group (> 3° deviation from neutral alignment).MethodsBetween 2000 and 2006, clinical and radiographic data of 334 primary TKAs were retrospectively reviewed to determine the 10-year Kaplan-Meier survival rate. Patients were divided into acceptable and outlier groups according to the mechanical axis checked postoperatively within a month. Clinical outcomes were assessed using Hospital for Special Surgery, Knee Society Score, and Western Ontario and McMaster Universities Osteoarthritis Index score preoperatively and at the final follow-up. Postoperative complications and revision rates were also evaluated.ResultsThe mean change in mechanical axis between the immediate postoperative examination and the last follow-up was greater in the outlier group (1.6 ± 2.7) than in the acceptable group (0.8 ± 2.4). The revision rates were significantly different between the two groups (p = 0.04). At the last follow-up, clinical scores were all improved in both groups compared to each preoperative condition. There were no significant differences in clinical scores between the two groups at the last follow-up. The 10-year Kaplan-Meier survival analysis showed a tendency towards better survival with restoration of neutral mechanical axis. However, the difference was not statistically significant (p = 0.25).ConclusionsRestoration of neutral limb alignment is a factor that can result in a lower revision rate and higher longevity in TKA. However, there were no significant differences in clinical outcomes between the two groups.
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