Increased ankle pain after total knee arthroplasty is associated with a preoperative lateralized gait and talar tilt, but not with ankle laxity or the range of motion of the subtalar joint.

Aims: Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Methods: Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively. Results: A total of 69 patients (varus n = 45; valgus n = 24) underwent TKA and completed the postoperative follow-up visit. Of these, 16 patients (23.2%) reported the onset or progression of ankle symptoms. Varus patients with increased ankle symptoms after TKA had a significantly higher pre- and postoperative TT. Valgus patients with ankle symptoms after TKA showed a pathologically lateralized gait line which could not be corrected through TKA. Patients who reported increased ankle pain neither had a decreased ROM of the subtalar joint nor increased ankle laxity following TKA. The preoperative mTFA did not correlate with the postoperative FFI (r = 0.037; p = 0.759). Conclusion: Approximately one-quarter of the patients developed ankle pain after TKA. If patients complain about ankle symptoms after TKA, standing radiographs of the ankle and a gait analysis could help in detecting a malaligned TT or a pathological gait.

Functional gait analysis reveals insufficient hindfoot compensation for varus and valgus osteoarthritis of the knee.

PURPOSE: The hindfoot is believed to compensate varus and valgus deformities of the knee by eversion and inversion movements. But these mechanisms were merely found in static radiologic measurements. The aim of this study was, therefore, to assess dynamic foot posture during gait using pressure-sensitive wireless insoles in patients with osteoarthritis of the knee and frontal knee deformities. METHODS: Patients with osteoarthritis of the knee were prospectively included in this study. Patients were clinically and radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), and talar tilt (TT)) exa mined. Gait line analysis was conducted using pressure-sensitive digital shoe insoles. RESULTS: Eighty-two patients (varus n = 52, valgus n = 30) were included in this prospective clinical study. Radiologically, the mTFA significantly correlated with the HAVA (cor = -0.72, p < 0.001) and with the TT (Pearson's cor = 0.32, p < 0.006). Gait analysis revealed that the gait lines in varus knee osteoarthritis were lateralized, despite the hindfoot valgus. In valgus knee osteoarthritis, gait lines were medialized, although the hindfoot compensated by varization. CONCLUSIONS: Functional dynamic gait analysis could demonstrate that the hindfoot is not able to sufficiently compensate for frontal malalignments of the knee joint, contrary to static radiologic findings. This led to a narrowing of the joint space of the ankle medially in varus and laterally in valgus knee osteoarthritis.

Retrospective analysis of treatment strategies and clinical outcome of isolated talar dislocations.

Talar dislocations are rare injuries of the foot and ankle and require quick and decisive diagnostic and therapeutic decisions. Evidence concerning the treatment and outcome of these injuries is sparse. The aim of this study was to analyze all talar dislocations of the last ten years treated in a large German level I trauma center in an effort to add to the experience on these injuries. METHODS: All patients with a talar dislocation injury were retrospectively included. Medical reports, x-ray and computertomography scans were analyzed for the sex, age, trauma mechanism, and injury classifications as well as for the clinical outcome as measured by the Foot Function Index (FFI). RESULTS: A total of 18 patients were included in this study: Luxatio pedis cum talo (n = 1), Luxatio tali totalis (n = 3), Luxatio pedis sub talo (n = 14). Analysis of the therapeutic algorithms revealed that only one patient was treated conservatively, the other 17 patients underwent operation. In most cases, stabilization was achieved using an external fixator and if necessary, the subtalar and talonavicular joints were temporarily stabilized using K-wires. The mean follow-up time was 4.25 years (2.05 SD) and the mean FFI-sum score 45.00 (42.26 SD). Two patients required subtalar fusion two years after the injury. CONCLUSION: Isolated talar dislocations can have a good outcome and be effectively treated in the emergency setting by basic techniqes if neurovasular structures are not injured. Often, these injuries are associated with fractures of adjacent bones which then need complex reconstruction.