The effect of tourniquets on patellofemoral joint congruity during total knee arthroplasty.

BACKGROUND: Incongruity of the patellofemoral joint after total knee arthroplasty (TKA) causes anterior knee pain. Intraoperative congruity tests are necessary to avoid unnecessary lateral retinacular release, and the usage of tourniquets may influence these results. The purpose of this study was to examine the effect of tourniquets on patellofemoral joint congruity during TKA. MATERIALS AND METHODS: Two hundreds and seventeen knees were examined after TKA. Skyline radiographs at 60° and 90° flexion were taken immediately after wound closure before and after tourniquet deflation to compare changes in patellar tilt angle. RESULTS: In the patellar tilt angle at 60° flexion, lateral tilt was observed in 18 knees. Tourniquet deflation changed the patellar tilt angle by a mean -0.7° ± 1.2° (p = 0.030). Medial tilt was observed in 10 knees. Tourniquet deflation changed the patellar tilt angle by 0.9° ± 0.7° (p = 0.004). Tourniquet deflation improved the degree of lateral and medial patellar tilt. In the patellar tilt angle at 90° flexion, lateral tilt was observed in 118 knees. Tourniquet deflation changed the patellar tilt angle by a mean -1.1° ± 1.2° (p < 0.001). Medial tilt was observed in 71 knees. Tourniquet deflation changed the patellar tilt angle by 0.5° ± 1.0° (p < 0.001). Tourniquet deflation improved the degree of lateral and medial patellar tilt. CONCLUSIONS: Tourniquet deflation improved patellofemoral congruity in a statistically significant way, but only to a small extent, indicating low clinical significance. Therefore, intraoperative congruity tests performed with tourniquets in place are reliable.

Elevation of the femur in THA through a direct anterior approach: cadaver and clinical studies.

BACKGROUND: The direct anterior approach in THA is an intermuscular approach that requires no muscle detachment. However, it is difficult to elevate the proximal femur for access to the femoral canal. QUESTIONS/PURPOSES: We asked (1) which part of the capsule should be released to allow effective elevation of the proximal femur; (2) whether the release of the internal obturator tendon allows elevation; and (3) whether hip hyperextension reduces the ability to elevate the femur. METHODS: We conducted a cadaver study and a clinical study. In the first study, the elevation of the proximal femur was measured in 6 hips in 3 cadavers after excision of the anterior capsule, after the release of the superior capsule or the posterior capsule, after the release of the superior and posterior capsule, and after the release of the internal obturator tendon under traction of 70 N. Each hip was positioned at 0°, 15°, and 25° hyperextension. In the second study of 39 patients, the posterior capsule was released after the superior capsule in the first 13 hips, and the superior capsule was released after the posterior capsule in the next 26 hips. The elevation achieved for each hip was measured as in the cadaver study. RESULTS: In our cadaver study, hip elevation increased after superior capsule release but not after release of the internal obturator tendon. After superior capsule release, the ability to elevate the femur was not diminished by hip hyperextension. In our clinical study, elevation increased after superior capsule release. CONCLUSIONS: Superior capsule release was most effective of all releases for elevating the proximal femur in the direct anterior approach.

Intra- and intersurgeon variability in image-free navigation system for THA.

In image-free navigation systems, cup orientation is determined in the pelvic coordinate by registration of bony landmarks. While the value of navigation relates primarily to the reliability and accuracy of cup placement, the reliability of registration plays a role in cup placement. We therefore examined intra- and intersurgeon variability in registration and the distance between registration points in each bony landmark. Thirty-seven THAs were performed in the lateral position and 15 THAs in the supine position. The cup was fixed using a navigation system. The registration was repeated two more times by operator and assistant, and the intra- and intersurgeon variability of cup abduction angle and anteversion was analyzed by ICC (intraclass correlation coefficients). In 25 hips, the distance between intrasurgeon registration points and between intersurgeon registration points in each landmark were calculated. The ICC in the lateral position ranged between 0.59 and 0.81, and between 0.85 and 0.95 in the supine position. The ICCs of cup abduction angle for the intra- and intersurgeon variability were 0.92 and 0.95 for the supine position and 0.65 and 0.59 for the lateral position. Those of anteversion were 0.93, 0.85, and 0.81, 0.72, respectively. The variability in locating the ASIS in the lateral position was greater than that in the supine position. The variability of registration points depended on bony landmarks and patient position but the range of variability we found would not likely result in a large variability in cup placement.

Intraoperative manipulation for flexion contracture during total knee arthroplasty.

BACKGROUND: Joint gap unbalancing during total knee arthroplasty (TKA) induces flexion contracture. Flexion contracture is one of the most serious complications of TKA. When flexion contracture is found during surgery, intraoperative manipulation is often empirically performed. We evaluated the effects of intraoperative manipulation on joint gap and postoperative flexion contracture. MATERIALS AND METHODS: TKA was performed for 136 knees. Intraoperative manipulation was performed for flexion contracture in 61 knees. Joint gap changes before and after manipulation were measured at six positions from extension to 120° of flexion. Manipulation was not performed for 75 knees. The extension angle was measured radiographically immediately after surgery, at 3 months, and 6 months postoperatively. Extension angles with manipulation and without manipulation were compared. RESULTS: Joint gap changes (mm) before and after manipulation were 0.1, 0.0, -0.2, -0.3, -0.1, and -0.3 at 0°, 30°, 45°, 60°, 90°, and 120° of flexion, respectively, indicating that manipulation could not change joint gaps significantly. Extension angles (°) with and without manipulation were -4.0 ± 4.6 and -3.8 ± 3.9 immediately after surgery, -5.3 ± 6.7 and -5.5 ± 6.2 at 3 months postoperatively, and -2.7 ± 6.0 and -3.8 ± 5.8 at 6 months postoperatively. No statistically significant difference existed between the values with or without manipulation during all periods. CONCLUSION: Intraoperative manipulation does not enlarge the gap or resolve postoperative flexion contracture. Developing the new surgical technique is required to achieve perfect balance at TKA.

Intraoperative Manipulation for Flexion Contracture During Total Knee Arthroplasty.

Joint gap balancing during total knee arthroplasty (TKA) is important for ensuring postoperative joint stability and range of motion. Although the joint gap should be balanced to ensure joint stability, it is not easy to achieve perfect balancing during TKA. In particular, relative extension gap shortening can induce flexion contracture. Intraoperative manipulation is often empirically performed. This study evaluated the tension required for this manipulation and investigated the influence of intraoperative manipulation on the joint gap in cadaveric knees. Total knee arthroplasty was performed in 6 cadaveric knees from whole body cadavers. Flexion contracture was induced using an insert that was 4 mm thicker than the extension gap, and intraoperative manipulation was performed. Study measurements included the changes in the joint gap after manipulation at 6 positions, with the knee bending from extension to 120° flexion, and the manipulation tension that was required to create a 4-mm increase in the gap. The manipulation tension needed to create a 4-mm increase in the extension gap was 303±17 N. The changes in the joint gap after manipulation were 0.4 mm, 0.6 mm, 0.2 mm, -0.2 mm, -0.4 mm, and -0.6 mm at 0°, 30°, 45°, 60°, 90°, and 120° flexion, respectively. Therefore, the joint gap was not significantly changed by the manipulation. Intraoperative manipulation does not resolve flexion contracture. Therefore, if flexion contracture occurs during TKA, treatment with additional bone cutting and soft tissue release is likely more appropriate than manipulation. [Orthopedics. 2016; 39(6):e1070-e1074.].

Pseudoaneurysm Accompanied by Crowe Type IV Developmental Dysplasia of the Hip: A Case Report.

We report the case of a 72-year-old woman whose pseudoaneurysm was difficult to diagnose and treat. The patient had a history of congenital dislocated hip and was undergoing anticoagulation therapy with warfarin due to the mitral valve replacement. Her chief complaint was pain and enlargement of the left buttock, and the laboratory tests revealed severe anemia. However, her elderly depression confused her chief complaint, and she was transferred to a psychiatric hospital. Two months after the onset of the symptoms, she was finally diagnosed with a pseudoaneurysm by contrast-enhanced CT and angiography. IDC coils were used for embolization. A plain CT showed hemostasis as well as a reduced hematoma at 2 months after the embolization. The possible contributing factors for the pseudoaneurysm included bleeding due to warfarin combined with an intramuscular hematoma accompanied by Crowe type IV developmental dysplasia of the hip that led to an arterial rupture by impingement between pelvis and femoral head. Since the warfarin treatment could not be halted due to the valve replacement, embolization was chosen for her treatment, and the treatment outcome was favorable.

Accuracy of cup height and medialization in THA for dysplastic hip osteoarthritis using an imageless navigation system.

In total hip arthroplasty (THA) for dysplastic hip osteoarthritis, bony deformity makes it difficult to identify the correct cup height and medialization. The authors developed a new technique for registration and navigation of cup position for dysplastic hips using an imageless navigation system. Eighty dysplastic hips (Crowe type I, n=58; type II, n=18; type III, n=4) underwent THA. Thirty-four hips were operated on while in the supine position and 46 hips were operated on while in the lateral position. Before capsulectomy, the anterior pelvic plane and the position of the femur were registered. After exposure of the acetabulum, the teardrop, posterior rim, and medial wall of the acetabulum were registered. Then the cup height, cup medialization, cup inclination, anteversion, and leg lengthening were navigated. The difference between the navigated and radiographic cup heights was 4.5 ± 4.0 mm, the difference in cup medialization was 3.0 ± 2.5 mm, the difference in cup inclination was 4.3° ± 3.1°, the difference in cup anteversion was 5.5° ± 3.8°, and the difference in leg lengthening was 3.7 ± 3.0 mm. Comparison of the first 20 cases with the last 20 cases showed that the accuracy of cup medialization was significantly improved. These differences were not affected by Crowe type or surgical position. Because the correct cup height and medialization are key issues in THA for dysplastic hip osteoarthritis, the accuracy of cup height and medialization in this imageless navigation system were acceptable for clinical application.