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A retrospective comparison of central and posterior hinge joints in 53 total knee arthroplasties
Arthur Justo1, Hugo Vilette1, Matthieu Ehlinger2
1Service de chirurgie orthopédique et traumatologique, Hôpital Pierre-Paul-Riquet, 1, place du Dr-Baylac, TSA 40 031, 31059 Toulouse cedex 9, France.
Insights
This study found no difference in implant survival between central (CHTKA) and posterior (PHTKA) hinged total knee arthroplasty. However, CHTKA showed improved flexion and patient-reported outcomes like VAS and IKS.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
Background:
- Hinged total knee arthroplasty (HTKA) is increasingly used.
- Two main hinge types exist: central (CHTKA) and posterior (PHTKA).
Purpose of the Study:
- To compare implant survival between CHTKA and PHTKA.
- To analyze radiological and clinical outcomes of CHTKA versus PHTKA.
Main Methods:
- Retrospective study of 53 patients undergoing HTKA (32 CHTKA, 21 PHTKA).
- Primary endpoint: revision rate. Secondary endpoints: mobility, complications, pain (VAS), function (IKS), and radiological progression.
- Mean follow-up of 51 months.
Main Results:
- No significant difference in overall HTKA survival at 60 months (81%) between CHTKA (77.7%) and PHTKA (85.7%).
- CHTKA demonstrated significantly better flexion (101° vs. 98°), reduced pain (VAS 0.5 vs. 1.6), and improved function (IKS 103 vs. 81) compared to PHTKA.
- No differences observed in radiological progression or complications.
Conclusions:
- Implant survival rates are comparable between CHTKA and PHTKA.
- CHTKA offers superior flexion, pain reduction, and functional outcomes.
- Surgeons should consider these clinical differences when selecting HTKA hinge type.
Introduction:
The number of hinged total knee arthroplasty (HTKA) procedures is constantly increasing. There are two hinge types: central (CHTKA) and posterior (PHTKA). The primary purpose of the study was to compare implant survival in patients with CHTKA versus PHTKA. The secondary purpose was to analyse the radiological and clinical results of the implants.
Hypothesis:
There is no difference between the two groups.
Materials And Methods:
This study involved 53 patients who received a HTKA for either primary, trauma or revision surgery, of these 32 were in the CHTKA group and 21 in the PHTKA group, with a mean age of 69 years (38-89). The exclusion criteria were: etiology of sepsis, incomplete records and refusal to use data. The revision rate, with the replacement of prosthetic components, was the primary endpoint. The secondary outcomes were: mobility, complications, VAS, IKS, Devane, Charnley and Oxford knee scores, and radiological progression.
Results:
The mean follow-up was 51 months (1-139). At 60 months, overall survival rate of the HTKA was 81%, with a confidence interval (CI) of 95% (71-93.2), and there was no difference between CHTKA and PHTKA, 77.7% (95% CI, 63.3-95.4) versus 85.7% (95% CI, 72-100), p=0.625, respectively. Flexion was 101°±15 (80-140) for CHTKA versus 98°±12 (30-130) for PHTKA, p=0.006. VAS was 0.5±16 (0-6) for CHTKA versus 1.6±14 (0-4) for PHTKA, p=0.000008. The IKS was 103±39 (15-180) for CHTKA versus 81±51 (9-200) for PHTKA, p=0.03. There were no differences in either radiological progression, complications or other functional scores.
Discussion:
No significant difference was observed between the survival of CHTKA and PHTKA. CHTKA had better flexion, reduced VAS and increased IKS. Surgeons should be aware of these findings and apply careful consideration to their choice of hinge.
Level Of Evidence:
IV; retrospective single-centre study.
