Soft tissue stabilization of the hinge position in medial closed wedge distal femoral osteotomy: an anatomical study.

BACKGROUND: Soft tissue has an important role in stabilizing the hinge point of medial closed wedge distal femoral osteotomy (MCWDFO). However, there are conflicting data on the soft tissue anatomy around the hinge point of MCWDFO and, therefore, further anatomical data are needed. The purposes of the study were to: 1) anatomically analyze the soft tissue around the hinge point of MCWDFO; 2) radiologically define the appropriate hinge point to prevent an unstable hinge fracture based on the result of the anatomical analysis; and 3) histologically analyze the soft tissue based on the result of the anatomical analysis. METHODS: In 20 cadaveric knees, the capsule attachment of the distal lateral side of the femur was marked with a radiopaque ball bearing. A digital planning tool was used to calculate the area of the marked capsule attachment around the ideal hinge point of MCWDFO on radiographs. The soft tissue around the hinge point was histologically examined and the periosteal thickness was measured and visualized graphically. The graph and radiograph were overlayed using image editing software, and the appropriate hinge position was determined based on the periosteal thickness. RESULTS: As a result, the periosteal thickness of the distal lateral femur tended to rapidly decrease from the metaphyseal region toward the diaphyseal region. The overlayed graph and radiograph revealed that the periosteal thickness changed in the region corresponding to the apex of the turning point of the femoral metaphysis in all cases. CONCLUSIONS: In conclusion, the periosteum might support the hinge of MCWDFO within the area surrounded by the apex of the turning point of the femoral metaphysis and the upper border of the posterior part of the lateral femoral condyle.

Soft Tissue Stabilization of the Hinge Position for Lateral Closing-Wedge Distal Femoral Osteotomy: An Anatomic Study.

Background: Soft tissue plays an important role in stabilizing the hinge point for osteotomy around the knee. However, insufficient data are available on the anatomic features of the soft tissue around the hinge position for lateral closing-wedge distal femoral osteotomy (LCWDFO). Purpose: To (1) anatomically analyze the soft tissue around the hinge position for LCWDFO, (2) histologically analyze the soft tissue based on the anatomic analysis results, and (3) radiologically define the appropriate hinge point to prevent unstable hinge fracture based on the results of the anatomic and histological analyses. Study Design: Descriptive laboratory study. Methods: In 20 cadaveric knees (age, 82.7 ± 7.8 years; range, 60-96 years), the soft tissue of the distal medial side of the femur was anatomically analyzed. The thicknesses of the periosteum and direct insertion of the adductor tendon (AT) were histologically examined and measured using an electron microscope. The thickness of the periosteum was visualized graphically, and the graph of the periosteum and radiograph of the knee were overlaid using image editing software. The appropriate hinge position was determined based on the periosteal thickness and attachment of the AT. Results: The mean thickness of the periosteum of the metaphysis was 352.7 ± 58.6 µm (range, 213.6-503.4 µm). The overlaid graph and radiograph revealed that the thickness of the periosteum changed at the part corresponding to the transition between the diaphyseal and metaphyseal ends of the femur. The mean width of the AT attached to the distal medial femur from the adductor tubercle toward the distal direction was 7.9 ± 1.3 mm (range, 6.3-9.7 mm). Conclusion: Results indicated that the periosteum and AT support the hinge for LCWDFO within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle. Clinical Relevance: When the hinge point is located within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle, these soft tissues work as stabilizers, and there is no risk of cutting into the joint space.

A case of extrapulmonary tuberculosis after use of baricitinib.

Extrapulmonary tuberculosis (TB) can occur in patients treated with Janus kinase (JAK) inhibitors. We present a case of rheumatoid arthritis complicated by extrapulmonary TB following baricitinib treatment. A 45-year-old Japanese woman was diagnosed with rheumatoid arthritis at another hospital, and she subsequently started treatment with methotrexate (MTX) at 6.0 mg/week and prednisolone at 3.0 mg/day at our institute. The MTX dose was increased to 10 mg/week, and clinical remission was achieved; however, the disease activity flared up 6 months after the initial visit. Isoniazid (INH) prophylaxis was started following positive T-SPOT® screening for TB, and baricitinib (Olumiant®) was introduced 3 weeks later because of an insufficient response to MTX. INH prophylaxis was continued for 6 months. Ten months after starting INH treatment, a painless mass was observed on the left side of the patient's neck. Magnetic resonance imaging showed enlarged lymph nodes with calcification. A subsequent biopsy and pathologic examination led to a diagnosis of tuberculous lymphadenitis, and the patient was started on anti-TB therapy. Ten months later, the patient was still in remission and doing well. Extrapulmonary TB can be difficult to diagnose because of inconsistent physical and laboratory findings. When treating patients with JAK inhibitors, physicians should be cognisant of the potential for extrapulmonary TB to develop.

Distal femoral osteotomy for genu valgum deformity caused by malunited Hoffa fracture.

Hoffa fractures are unstable intra-articular fractures of the femoral condyle that occur in the coronal plane.Insufficient anatomical reduction and internal fixation may lead to non-union or malunion. A 39-year-old man was involved in a traffic accident while riding a motorcycle and was diagnosed with left Hoffa fracture and avulsion fracture of the femoral attachment of the medial collateral ligament. Open reduction and internal fixation were performed 5 days after injury. The patient experienced intermittent knee pain, joint contracture and deformity, and attended our hospital for further treatment 18 months after surgery. CT revealed depression and malunion of the posterior aspect of the lateral femoral condyle, and weight-bearing X-ray showed valgus deformity due to malunion. Distal femoral osteotomy (DFO) was performed and good functional and radiographic results were obtained. This report suggests that DFO is a reasonable treatment for young patients suffering from malalignment due to malunited Hoffa fracture.