Association between changes in hip-knee-ankle angle and hindfoot alignment after total knee arthroplasty for varus knee osteoarthritis

Abstract

Background The change in hip-knee-ankle (HKA) angle after total knee arthroplasty (TKA) may cause an adjustment in hindfoot alignment (HFA). However, the relationship between the changes in HKA angle and HFA is still not well studied. This study aimed to investigate the association between HKA angle and hindfoot alignment changes after TKA for varus knee osteoarthritis. Methods A prospective study was carried out in which 108 patients with varus knee deformities were radiographically and clinically evaluated before and 3 months after TKA. The relationship of change in HFA with correction in HKA angle was investigated. Results The results showed that the HFA was adjusted significantly by 3 months after TKA (p < 0.001), along with improved American Orthopaedic Foot and Ankle Society (AOFAS) ankle hindfoot score (p < 0.001). Next, a univariate correlation and linear regression analysis showed that the change in HFA was weakly correlated with the change in HKA angle (r=-0.262, β=-0.14, 95 % CI: -0.23 to -0.04, P = 0.006). Further stratified analysis and interaction tests revealed that age has a distinct effect on the correlation between the changes in HFA and HKA angle. The correlation was dramatically greater in the group under 65 years (r=-0.474, β=-0.26, 95 % CI: -0.41 to -0.12, P = 0.001), whilst, no correlation was observed in those above 65 years old (r=-0.036, β=-0.02, 95 % CI: -0.14 to 0.11, P = 0.779). Conclusions Our findings indicated that correction of HKA after TKA tend to promote adjustment in the hindfoot alignment toward re-balance of the whole lower limb weight-bearing axis. However, this mechanism obviously weakens in elderly patients. Therefore, if apparent hindfoot deformity exists in these patients before TKA, more perioperative intervention is required for hindfoot adjustment, and even HKA undercorrection may be considered.

Evaluation of the hindfoot alignment before and after total knee arthroplasty

“…Therefore, when evaluating the SJ, it is necessary to evaluate both the hindfoot and the AJLO. Diao et al 2 evaluated changes in the HKA and hindfoot angle before and after TKA and showed a correlation between postoperative HKA improvement and the hindfoot angle. However, they did not evaluate SJ mobility.…”

Joint line obliquity after lateral closing‐wedge high tibial osteotomy does not adversely affect clinical and radiological outcome: a 5‐year follow‐up study

“…Medial joint space width (mJSW) was measured by the minimum interbone distance between the medial tibial plateau and the medial femoral condyle [ 39 ]. HKA was measured by the angle between the femoral mechanical axis and the tibial mechanical axis [ 6 ]. The mLDFA was measured by the lateral angle between the tangential line of the femoral condyles and the femoral mechanical axis [ 32 ].…”

The amount of femorotibial alignment correction through total knee arthroplasty may affect postoperative hindfoot alignment

“…Change of tibiofemoral alignment at the knee joint level after total knee arthroplasty (TKA) is associated with hindfoot alignment [ 11 ]. Many studies have shown that neutralizing varus femorotibial alignment with TKA can also neutralize valgus hindfoot alignment [ 1 , 2 , 3 , 4 , 5 , 6 , 10 , 11 , 12 , 13 ].…”

“…In patients of severe preoperative varus femorotibial alignment, a greater amount of alignment correction is required at the level of the knee joint in TKA. There have been conflicting reports about the relationship between the amount of alignment correction and the improvement of hindfoot alignment [ 1 , 2 , 3 , 4 , 6 , 10 ]. Some studies showed that the change in hindfoot alignment was correlated with the change in femorotibial alignment [ 2 , 3 , 6 , 10 ], whereas others showed no such relationship [ 1 , 4 ].…”

“…There have been conflicting reports about the relationship between the amount of alignment correction and the improvement of hindfoot alignment [ 1 , 2 , 3 , 4 , 6 , 10 ]. Some studies showed that the change in hindfoot alignment was correlated with the change in femorotibial alignment [ 2 , 3 , 6 , 10 ], whereas others showed no such relationship [ 1 , 4 ]. In addition, few investigators conducted direct interviews with patients regarding complaints about the hindfoot after TKA [ 7 ].…”