Reduction of postoperative nausea and vomiting risk in the second stage during bilateral total knee arthroplasty with a 1-week interval.

PURPOSE: Total knee arthroplasty (TKA) is often performed sequentially on both sides during a single hospital stay. Patients who experience postoperative nausea and vomiting (PONV) after the first operation are concerned about PONV recurrence after the second operation. However, there are few studies regarding the incidence of PONV in staged bilateral TKA with a ≥ 1-week interval. This study aimed to identify the differences in (1) PONV incidence, (2) use of rescue antiemetics, and (3) the amount of opioid consumption between the first and second operations for staged bilateral TKA with a 1-week interval. Based on our anecdotal experience, the hypothesis of this study was that during staged bilateral TKA at a 1-week interval, the PONV incidence and rescue antiemetic requirement after the second operation will be lower than those after the first operation, regardless of opioid consumption. METHODS: Fifty-eight consecutive patients who underwent staged bilateral TKA with a 1-week interval were retrospectively reviewed. All second-stage operations were performed with the same anaesthesia protocol and perioperative patient management protocol as the first-stage operation. PONV incidence was the primary outcome. The requirement for rescue antiemetic drugs and the amount of opioid consumption were secondary outcome variables. The outcome variables were recorded during three postoperative days (Days 0-2) for each stage and were compared between the first and second operations. RESULTS: The incidence rates of nausea and vomiting on Day 0 (p = 0.001 and p = 0.004, respectively) and nausea on Day 1 (p = 0.008) were significantly lower after the second operation. Rescue antiemetic use on Day 0 was significantly lower after the second operation (p = 0.001). The total opioid consumption 72 h after surgery was significantly higher after the second operation (61.76 vs. 34.28 mg, p < 0.001). CONCLUSION: During staged bilateral TKA with a 1-week interval, PONV incidence was lower after the second operation, even with increased opioid consumption. LEVEL OF EVIDENCE: III.

The Fate of Lumbar Facet Cyst After Indirect Decompression Using Oblique Lateral Interbody Fusion in Degenerative Spondylolisthesis.

Favorable clinical outcomes have been reported for oblique lateral interbody fusion (OLIF) for various lumbar degenerative diseases. However, there is only limited evidence on the safety and effectiveness of OLIF in degenerative spondylolisthesis with lumbar facet cyst (LFC), and OLIF is often regarded as a relative contraindication for these patients. The authors prospectively enrolled patients who underwent a single-level OLIF for degenerative spondylolisthesis with LFC to evaluate the morphological changes of LFC and their clinical significance following OLIF. Twenty patients with a mean age of 69.6 years (range, 65-86 years) were enrolled. At 1 week postoperative, 5 (25%) patients had a residual cyst, whereas 15 (75%) patients had completely resolved cysts on magnetic resonance imaging (MRI). No patient had a residual cyst on the 1-year postoperative MRI. Patients with cyst resolution (n=15) on the 1-week postoperative MRI had a larger slip percentage difference on the preoperative dynamic radiograph when compared with patients with no cyst resolution (n=5) (4.7%±2.8% vs 1.3%±0.3%, P=.002). The group with cyst resolution also showed a greater expansion of facet fluid width following OLIF, although this was not statistically significant (1.2±0.7 mm vs 0.7±0.5 mm, P=.098). For both groups, all preoperative clinical scores showed a significant improvement at 1 year after OLIF, but there was no significant difference between the groups at all time points. Preliminary 1-year follow-up results from this prospective series suggest that OLIF can be a useful option for fusion surgery in LFC patients with apparent segmental instability. [Orthopedics. 2021;44(5):306-312.].

Leg-length discrepancy and associated risk factors after paediatric femur shaft fracture: a multicentre study.

PURPOSE: This study was performed to investigate leg-length discrepancy (LLD) and associated risk factors after paediatric femur shaft fractures. METHODS: A total of 72 consecutive patients under 13 years old (mean age 6.7 years; 48 boys, 24 girls) with unilateral femur shaft fracture, and a minimum follow-up of 18 months, were included. The amount of LLD was calculated by subtracting the length of the uninjured from that of the injured limb. Risk factors for an LLD ≥ 1 cm and ≥ 2 cm were analyzed using multivariable logistic regression analysis. RESULTS: Hip spica casting, titanium elastic nailing and plating were performed on 22, 40 and ten patients, respectively. The mean LLD was 7.8 mm (sd 8.8) and 29 (40.3%) had a LLD of ≥ 1 cm, while nine (12.5%) had a LLD of ≥ 2 cm. There were significant differences in fracture stability (p = 0.005) and treatment methods (p = 0.011) between patients with LLD < 1 cm and ≥ 1 cm. There were significant differences in fracture site shortening (p < 0.001) and LLD (p < 0.001) between patients with length-stable and length-unstable fractures. Fracture stability was the only factor associated with LLD ≥ 1 cm (odds ratio of 4.0; p = 0.020) in the multivariable analysis. CONCLUSION: This study demonstrated that fracture stability was significantly associated with LLD after paediatric femur shaft fractures. Therefore, the surgeon should consider the possibility of LLD after length-stable femur shaft fracture in children. LEVEL OF EVIDENCE: Prognostic level III.

Distribution of the Force in the Knee Joint during Daily Activities after Open Wedge High Tibial Osteotomy: A Rationale for the Proper Postoperative Management.

The present study was conducted to evaluate the force distribution in knee joint during daily activities after open-wedge high tibial osteotomy (OWHTO). A three-dimensional proximal tibial finite element model (FEM) was created using Mimics software to evaluate computed tomography (CT) scans of the tibia after OWHTO. The anterior and posterior gaps were 7.0 and 12.1 mm, respectively, and the target opening angle was 12 degrees. The loading ratio of the medial and lateral tibial plateaus was 6:4. To evaluate force distribution in the knee joint during activities of daily living (ADLs) after OWHTO, peak von Mises stresses (PVMSs) were analyzed at the plate and posterolateral edge region of osteotomized tibia. ADLs associated with greater knee flexion (sitting 90 degrees, standing 90 degrees, bending 90 degrees, stepping up stairs 60 degrees, and stepping downstairs 30 and 60 degrees) yielded PVMSs ranging from 195.2 to 221.5 MPa at the posterolateral edge region. In particular, stepping downstairs with knee flexion to 60 degrees produced the highest PVMS (221.5 MPa), greater than the yield strength (100-200 MPa). The highest plate PVMS was greater than 300 MPa during ADLs associated with flexion angles of approximately 90 degrees. However, these values did not exceed the yield stress (760.0 MPa). Conclusively, higher force was generated during higher flexion associated with weight-bearing and stepping downstairs produced a high force (even at lower flexion) on the posterolateral area of the tibial plateau. Therefore, a caution should be exercised when engaging in knee flexion of approximately 90 degrees and stepping downstairs in the early postoperative period when patients follow a weight-bearing rehabilitation protocol. However, this study is based on modeling; further translational studies are needed prior to clinical application.