Postoperative tibial slope size does not affect five-year wear in total knee arthroplastyKnee Replacement Alignment Linked to Implant Loosening

The bone & joint journal Published May 1, 2026 Study authors: de Ridder Ruud, Kaptein Bart L, Pijls Bart G, Nelissen Rob G H H, Kaptijn Herman H PubMed ↗ DOI ↗ Editorial oversight: Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

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Key Takeaway

Note that larger postoperative tibial slope associates with greater posterior tilting but not increased wear at five years.

This observational study utilized secondary analysis of a randomized controlled trial involving 93 patients undergoing total knee arthroplasty. The population consisted of 93 TKAs on insert materials. The setting and publication type were not reported. Funding or conflicts of interest were not reported.

The intervention or exposure was the postoperative tibial slope, categorized as small (≤ 5°), intermediate (6° to 9°), and large (≥ 10°). The comparator groups included the small (≤ 5°) and intermediate (6° to 9°) slope groups. The primary outcome measured five-year tibial component migration and wear. The follow-up duration was 60.0 months.

Main results showed an association between tibial component migration and postoperative tibial slope. The group with the largest postoperative tibial slope showed the largest posterior tilting. There was no difference in insert wear between small, intermediate, and large slope groups at five years. Additionally, there was no association between postoperative slope and functional or patient-reported outcomes. Absolute numbers and p-values were not reported.

Safety data regarding adverse events, serious adverse events, discontinuations, and tolerability were not reported. The study limitations were not reported. Causality was not reported. The practice relevance was not reported. The certainty note was not reported. The study design was observational, so causal language is avoided.

A new analysis of data from a previous trial looked at how the angle of the knee after total knee replacement affects implant stability. The study included 93 patients who had knee replacements with different types of plastic inserts. Researchers measured the tibial slope, which is the angle of the top of the shinbone, and grouped patients into small, intermediate, or large slope groups.

After five years, the group with the largest tibial slope showed more tilting of the implant. However, there was no difference in wear of the plastic insert among the groups. Also, the slope did not affect how well patients felt or functioned.

This is an observational analysis, so it cannot prove that the slope caused the implant to shift. Other factors could be involved. The study did not report any safety concerns or side effects.

For now, the findings suggest that surgeons may want to pay attention to the angle of the knee during replacement. But more research is needed to confirm this link and to see if adjusting the slope leads to better long-term outcomes.

What this means for you:

Larger knee angle after replacement may be linked to more implant movement, but function and wear were not affected.

Study Details

Study typeRct

EvidenceLevel 2

Follow-up60.0 mo

PublishedMay 2026

PMID42061874

View Original Abstract ↓

AIMS: The primary objective of this study was to evaluate the influence of postoperative slope on the five-year tibial component migration and wear following uncemented cruciate-retaining condylar-stabilized total knee arthroplasty (TKA). Secondary objectives included the association between postoperative slope and clinical and functional outcomes. METHODS: This observational study was a secondary analysis of a randomized controlled trial of 93 TKAs on insert materials. Tibial component migration and insert wear were measured across three postoperative slope groups (small (≤ 5°), intermediate (6° to 9°), and large (≥ 10°)) using radiostereometric analysis at three, six, 12, 24, and 60 months postoperatively. Patient-reported outcome measures were collected preoperatively and at all follow-up timepoints. RESULTS: There was an association between tibial component migration and postoperative tibial slope: the group with the largest postoperative tibial slope showed the largest posterior tilting. At five years, there was no difference in insert wear between the small, intermediate, and large slope groups. There was also no association between postoperative slope and functional or patient-reported outcomes. CONCLUSION: TKA implanted with more than 10° of slope showed increased tibial component migration and posterior tilting, independent of the native slope. At five years, there was no influence of slope on wear or functional outcomes.

Postoperative tibial slope size does not affect five-year wear in total knee arthroplastyKnee Replacement Alignment Linked to Implant Loosening

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