Normo-or slightly overcorrection show better results after medial closing wedge high tibial osteotomy.

PURPOSE: The objectives of this study were to evaluate functional results, revision-free survival, and the influence of postoperative alignment on outcomes after MCWHTO. METHODS: This retrospective study included 27 MCWHTO operated on from 2009 to 2021. Radiographic measurements were performed pre- and postoperatively. The HKA (Hip-Knee-Ankle angle), MPTA (Medial Proximal Tibial angle), LDFA (Lateral Distal Femoral Angle), JLO (Joint Line Obliquity), and JLCA (Joint Line Convergence Angle) were evaluated. The Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Society (IKS) Function and Knee Score, and the Subjective Knee Value (SKV) as well as revision-free survival were evaluated. Postoperative alignment and its influence on clinical outcomes were also analysed. RESULTS: The mean follow-up was 61.9 months ± 31.4 (13-124). The HKA, MPTA, and JLCA angles were decreased post-operatively (respectively, Δ = 5.9° ± 2.6, p < 0.001; Δ = 6.1° ± 3.2, p < 0.001 and Δ = 2.5° ± 1.9, p < 0.001). LDFA and JLO were unchanged, post-operatively (respectively, Δ = 0.1° ± 2.2, p = 0.93 and Δ = 1.2° ± 3.3, p = 0.23). Postoperative HKA correlated with knee IKS (R = - 0.15, p = 0.04) and function IKS (R = - 0.44, p = 0.03). Postoperative LDFA correlated with knee IKS(R = 0.8, p < 0.01). Patients with postoperative HKA ≤ 180° had better KOOS (Δ = 12.3, p = 0.04) and IKS function (Δ = 28.1, p < 0.01) than those with HKA > 180°. CONCLUSION: Functional results and revision-free survival after MCWHTO are satisfactory when the deformity is located in the proximal tibia. The joint line obliquity is not significantly altered with small tibial correction and, obtaining an overall neutral or slightly varus alignment under the conditions of this study allowed an improvement in the postoperative clinical scores. The literature is still inconclusive on the ideal alignment for valgus deformities and larger series are needed to draw definitive conclusions. LEVEL OF EVIDENCE: IV, case series.

Restoration of preoperative tibial alignment improves functional results after medial unicompartmental knee arthroplasty.

PURPOSE: The alignment obtained after unicompartmental knee arthroplasty (UKA) influences the risk of failure. Kinematic alignment after UKA based on Cartier angle restauration is likely to improve clinical outcomes compared with mechanical alignment. The purpose of this study is to analyze the influence of implant alignment and native knee restoration after UKA using the conventional techniques on clinical outcomes. METHODS: This retrospective study included 144 medial UKA patients from 2015 to 2020. Radiographic measurements were performed pre- and postoperatively. Outliers were defined as follows: Δ Cartier > 3° (difference between the preoperative and postoperative Cartier angle); Δ MPTA (Medial Proximal Tibial angle) and postoperative TCA (Tibial Coronal component Angle) > 3° (difference between the positioning of the tibial implant and the preoperative proximal tibial deformity). The Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Society (IKS) Function and Knee score, the Forgotten Joint Score (FJS), and the Subjective Knee Value (SKV) were evaluated. A Student t test or a non-parametric Wilcoxon test was used for non-normal data to compare pre- and postoperative values for functional scores and angular measurements. The correlation of postoperative angles with functional outcomes was assessed by the Spearman's rank correlation coefficient. RESULTS: During the inclusion period, 214 patients underwent medial UKA, 71 patients were excluded, and 19 were lost to follow-up leaving 124 patients with 144 knees (20 bilateral UKA) included for analysis with a mean follow-up of 54.7 months ± 22.1 (24-95). The Δ Cartier was significantly correlated with IKS function (R2 = 0.06, p < 0.001) and FJS (R2 = 0.05, p < 0.01) scores. The Δ preoperative MPTA-TCA was significantly correlated (p < 0.001) with KOOS (R2 = 0.38), IKS Knee (R2 = 0.17), IKS function (R2 = 0.34), SKV (R2 = 0.08), and FJS (R2 = 0.37) scores. In subgroup analysis, non-outliers (< 3°) for Δ preoperative MPTA-TCA had better KOOS score (Δ = 23.5, p < 0.001) and IKS Function (Δ = 17.7, p < 0.001) compared to outliers (> 3°) patients. CONCLUSION: Functional results after medial UKA can be influenced by implant alignment in the coronal plane with slight clinical improvement when positioning the tibial implant close to the preoperative tibial deformity, rather than by restoring the Cartier angle. This series suggests the interest of a more personalized alignment strategy, but these results will have to be confirmed by other controlled studies. LEVEL OF EVIDENCE: IV, retrospective case series.

Acute compartment syndrome of the lower limbs: Fasciotomy or dermofasciotomy? A cadaver study of compartment pressures.

BACKGROUND: Acute compartment syndrome (ACS) of the lower limbs is a function-threatening event usually managed by extended dermofasciotomy. Closure of the skin may be delayed, creating a risk of complications when there is an underlying fracture. Early treatment at the pre-ACS stage might allow isolated fasciotomy with no skin incision. The primary objective of this study was to compare intracompartmental pressure (ICP) changes after fasciotomy and after dermofasciotomy. The secondary objectives were to evaluate potential associations linking the starting ICP to achievement of an ICP below the physiological cut-off of 10mm Hg and to determine whether the ICP changes after fasciotomy and dermofasciotomy varied across muscle compartments. HYPOTHESIS: Fasciotomy with no skin incision may not provide a sufficient ICP decrease, depending on the initial ICP value. MATERIAL AND METHODS: A previously validated model of cadaver ACS of the lower limbs was used. Saline was injected gradually to raise the ICP to>15mmHg (ICP15), >30mmHg (ICP30), and >50mmHg (ICP50). We studied 70 leg compartments (anterior, lateral, and superficial posterior) in 13 cadavers (mean age, 89.1±4.6years). ICP was monitored continuously. Percutaneous, minimally invasive fasciotomy consisting in one to three 1-cm incisions was performed in each compartment. ICP was measured before and after fasciotomy then after subsequent skin incision. The objective was to decrease the ICP below 10mmHg after fasciotomy or dermofasciotomy. RESULTS: Overall, mean ICP was 37.8±19.1mmHg after the injection of 184.0±133.01mL of saline. In the ICP15 group, the mean ICP of 16.1mmHg fell to 1.4mmHg after fasciotomy (ΔF=14.7) and 0.3mmHg after dermofasciotomy (ΔDF=1.1). Corresponding values in the ICP30 group were 33.9mmHg, 4.7mmHg (ΔF=29.2), and 1.2mmHg (ΔDF=3.5); and in the ICP50 group, 63.7mmHg, 17.0mmHg (ΔF=46.7), and 1.2mmHg (ΔDF=15.8). Thus, in the group with initial pressures >50mmHg, the ICP decrease was greater after both procedures, but fasciotomy alone nonetheless failed to achieve physiological values (<10mmHg). The pressure changes were not significantly associated with the compartment involved (anterior, lateral, or superficial posterior) (p<0.05). CONCLUSION: Under the conditions of this study, higher baseline ICPs were associated with larger ICP drops after fasciotomy and dermofasciotomy. Nevertheless, when the baseline ICP exceeded 50mmHg, fasciotomy alone failed to decrease the ICP below 10mmHg. Adding a skin incision achieved this goal. LEVEL OF EVIDENCE: IV, experimental study.