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. 2008 Jun;32(3):345-53.
doi: 10.1007/s00264-007-0340-y. Epub 2007 Mar 9.

Optimising femoral component rotation using Equiflex instrumentation: a clinical review

Ranjith R Kuzhupilly  1 , Ilias Seferiadis, Iain A C Lennox
Affiliations

Optimising femoral component rotation using Equiflex instrumentation: a clinical review

Ranjith R Kuzhupilly et al. Int Orthop. 2008 Jun.

Abstract
in English, French

Although there is agreement that flexion and extension spaces should be symmetrical and that rotation of the femoral component impacts outcome in a knee replacement, there is dispute over what is the 'correct' rotation and how best to achieve it (Akagi et al., Clin Orthop Relat Res 366:155-163, 1999; Anouchi et al., Clin Orthop Relat Res 287:170-177, 1993; Barrack et al., Clin Orthop Relat Res 392:46-55, 2001; Berger et al., Clin Orthop Relat Res 356:144-153, 1998; Jenny and Boeri, Acta Orthop Scand 75(1):74-77, 2004; Poilvache et al., Clin Orthop Relat Res 331:35-46, 1996; Siston et al., J Bone Joint Surg Am 87(10):2276-2280, 2005). Insall and Scuderi recommended placing a tensor in flexion and rotating the femoral cutting block so that its posterior edge is parallel to the cut tibia (Insall, Surgery of the knee, vol 2, 2nd edn., Churchill Livingstone, New York, 1993; Scuderi and Insall, Orthop Clin N Am 20:71-78, 1989). We feel Equiflex instrumentation will reliably achieve Insall and Scuderi's recommendation. To evaluate early results and lateral retinacular release rates using Equiflex instrumentation for TKR, we evaluated 209 consecutive knees (31 valgus, 178 varus) using this technique from 4 April 2005 until 19 September 2006. Pre and postop American Knee Society and Oxford scores, deformity, ROM, lateral retinacular release rates and complications were recorded. We could correct alignment and achieve our technical goals in 99% of cases. A lateral retinacular release was required in only five knees (2.4%). The complications are comparable to published data. The Equiflex instrumentation does help in equalising flexion-extension gaps, improves patellar tracking and reduces the incidence of lateral retinacular release.

Les praticiens sont tous d’accord: lors de la réalisation d’une prothèse du genfsou il faut réaliser celle-ci avec un espace identique en flexion et en extension par contre, le problème de la rotation est beaucoup plus discuté (Akagi et al., Clin Orthop Relat Res 366:155–163, 1999; Anouchi et al., Clin Orthop Relat Res 287:170–177, 1993; Barrack et al., Clin Orthop Relat Res 392:46–55, 2001; Berger et al., Clin Orthop Relat Res 356:144–153, 1998; Jenny and Boeri, Acta Orthop Scand 75(1):74–77, 2004; Poilvache et al., Clin Orthop Relat Res 331:35–46, 1996; Siston et al., J Bone Joint Surg Am 87(10):2276–2280, 2005). Insall et Scuderi recommandent de placer le tenseur en flexion rotation de façon à avoir une coupe des condyles postérieurs parallèles à la coupe tibiale (Insall, Surgery of the knee, vol 2, 2nd edn., Churchill Livingstone, New York, 1993; Scuderi and Insall, Orthop Clin N Am 20:71–78, 1989). Le matériel ancillaire Equiflex permet de réaliser cette préconisation d’Insall et Scuderi. Le propos de cette étude est d’évaluer les résultats précoces et le taux de release externe en utilisant cette méthode. Nous avons évalué 209 prothèses du genou consécutives (31 valgus, 178 varus) en utilisant cette technique. Ces patients ont été traités du 4 avril 05 au 19 septembre 06. Les résultats ont été évalués par le score de l’American Society et le score d’Oxford en pré et post-opératoire. La déviation axiale, la mobilité, les releases et les complications ont été également évalués. Résultat : Nous pouvons aligner correctement les genoux selon cette technique dans 99% des cas. Un release externe a été nécessaire uniquement dans 5 genoux (2.4%). Conclusions: les complications sont comparables aux données de la littérature. Finalement l’instrumentation Equiflex permet la réalisation d’un espace identique en flexion et en extension, améliore le fonctionnement fémoro patellaire et diminue l’importance des releases externes.

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Figures

Fig. 1
Fig. 1
a Equiflex spacer with sawn-off top-plate used for measuring flexion gap. b Equiflex spacer showing knurled ratchet and graduations from 8 mm–22 mm (side view)
Fig. 2
Fig. 2
a Femoral cutting block showing the modular adjustable midline stems. b Femoral cutting block with anterior referencing guide
Fig. 3
Fig. 3
Checking overall alignment after distal femoral cut and ligament balancing
Fig. 4
Fig. 4
Assessing and balancing the flexion gap with Equiflex spacer in situ
Fig. 5
Fig. 5
Checking for patellar tracking
Fig. 6
Fig. 6
Postop results
See this image and copyright information in PMC

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