There is a lack of knowledge about coronal alignment variability in
osteoarthritic knees. Therefore, the purpose of this article was to
systematically review the literature and collect data about the
lower limb alignment including hip-knee-ankle angle (HKA), femoral
mechanical angle (FMA), tibial mechanical angle (TMA) and the joint
line convergence angle (JLCA) in osteoarthritic knees.
A systematic review was performed using the electronic databases
MEDLINE (PubMed), EMBASE and Google Scholar. The following keywords
were used: (morphology OR geometr* OR anatomy OR alignment OR
phenotypes), (coronal OR neutral OR varus OR valgus), (knee OR lower
limb OR femur OR tibia) and (osteoarthritis OR arthritis). Out of
110 full-text articles retrieved, 15 studies were included.
Demographic information included author's names, year of
publication, imaging modality, sample size and patient demographics
(i.e. sex, age, etc.). Descriptive statistics, such as means,
ranges, and measures of variance [e.g. standard deviations, 95%
confidence intervals (CI)] for all angles (HKA, FMA, TMA, JLCA) are
Thirteen studies reported mean overall HKA angles ranging from
163.5° ± 2.3° to
179.9° ± 4.8°. The mean HKA angles in
females were between 164.1° ± 7.2° and
178.8° ± 4.8°, and in
males between 163.4° ± 5.5° and
177.4° ± 3.9°. The lowest and highest
reported HKA angles were - 27.7° and + 22.0°,
respectively. Seven studies reported mean FMA angles. Mean values
ranged from 92.7° ± 2.7° valgus to
88.6° ± 2° varus. The reported mean
FMAs for male were 87.9° ± 0.5° to
90.7° ± 3° and for female
89.91° ± 2.8° to
92.9° ± 3.1°. Six studies reported mean
TMA values. TMA ranged from
81.7° ± 3.9° varus to
87.7° ± 4.1° varus. Only three studies
reported mean JLCA angles, which ranged from - 4.3° to
- 6.4° ± 3.8°.
LEVEL OF EVIDENCE
Osteoarthritic knees showed a huge variation in overall coronal limb
alignment as well as in femoral and tibial coronal alignment.
Current total knee arthroplasty (TKA) alignment philosophies and
preoperative planning do not sufficiently consider these variation,
which might be one reason for unhappy knees after TKA.
IV, systematic review.