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CURRENT CONCEPTS

TKR Component Malrotation:

A Common Unrecognized Cause

of Pain & Stiffness

Dr. Christopher Vertullo MBBS FRACS

Orthopaedic Surgery & Sports
Medicine Centre, Bond University,

Griffith University

Background

While Total Knee Replacement (TKR) is a highly successful
surgical intervention for end stage knee osteoarthritis, a

significant proportion of patients unfortunately remain
dissatisfied after TKR. Younger active patients are more likely 02

to be dissatisfied and undergo subsequent revision as a
result.

Pain and stiffness with consequently reduced function is the All stiff TKRs in this series had internal rotation of either one
component or both. Bhattee et al. in 2013 reported a series
most common cause of patient dissatisfaction. Increasing
evidence suggests that femoral and tibial component internal of 23 TKR cases with unresurfaced patella’s and anterior
rotation is a very potent cause of both pain and stiffness knee pain. All 23 had some degree of internal rotation on

after TKR. Berger et al. in 1998 reported on patellofemoral CT scan. The 61% who remained dissatisfied after patella
complications in internally rotated components requiring resurfacing had a mean of 2.88o femoral internal rotation

revision. Barrack et al. in 2001 linked anterior knee pain after compared to 0.92o internal rotation in the satisfied group.
TKR to component mal-rotation despite normal alignment,
Marked component internal rotation can also result in
with a five times greater risk of anterior knee pain in the extensor mechanism mal-tracking, with patella dislocation,
internally rotated group. Nicoll and Rowley reported in 2010,
fracture or avascular necrosis as a result. Higher rates of
56% of 36 painful TKRs having rotational errors in a series lateral release in patella avascular necrosis cases may not be
of 740, compared to pain free TKRs. B̀dard et al. in 2011
only due to vascular issues but also mal-tracking issues due
reported improved range of motion after revision TKR for to malrotation. In the Australian National Joint Replacement
stiffness of a series of internally rotated tibial components Registry (ANJRR) 26.4% of revisions were performed for
with a pre-operative range of 10.1o – 71.5o to a improved
either pain, patellofemoral pain or arthrofibrosis, suggesting
post–operative range 0.8o–100o.
the majority of these patients had internally rotated

components. Only component loosening or lysis results
in more revisions in the ANJRR. There is evidence that

posterior stabilized components are more prone to pain with
malrotation.

Interestingly, while in the last decade a large amount of effort

has gone towards devising methods to improve TKR coronal
plane alignment, such as navigation and patient specific

instrumentation, the role of coronal plane mal-alignment as
an isolated cause of pain, stiffness and prosthesis failure
remains unclear in modern prostheses. By 2013, only 2.2%

patients underwent revision for mal-alignment in the ANJRR.

No series has reported component external rotation of
having a detrimental effect, with pain-free well – functioning

comparator TKRs having a mean of a few degrees of
external rotation of both tibial and femur.

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24 ISAKOS NEWSLETTER 2014: Volume II