RESUMEN

AIMS: Traditionally, total hip arthroplasty (THA) templating has been performed on anteroposterior (AP) pelvis radiographs. Recently, additional AP hip radiographs have been recommended for accurate measurement of the femoral offset (FO). To verify this claim, this study aimed to establish quantitative data of the measurement error of the FO in relation to leg position and X-ray source position using a newly developed geometric model and clinical data. METHODS: We analyzed the FOs measured on AP hip and pelvis radiographs in a prospective consecutive series of 55 patients undergoing unilateral primary THA for hip osteoarthritis. To determine sample size, a power analysis was performed. Patients' position and X-ray beam setting followed a standardized protocol to achieve reproducible projections. All images were calibrated with the KingMark calibration system. In addition, a geometric model was created to evaluate both the effects of leg position (rotation and abduction/adduction) and the effects of X-ray source position on FO measurement. RESULTS: The mean FOs measured on AP hip and pelvis radiographs were 38.0 mm (SD 6.4) and 36.6 mm (SD 6.3) (p < 0.001), respectively. Radiological view had a smaller effect on FO measurement than inaccurate leg positioning. The model showed a non-linear relationship between projected FO and femoral neck orientation; at 30° external neck rotation (with reference to the detector plane), a true FO of 40 mm was underestimated by up to 20% (7.8 mm). With a neutral to mild external neck rotation (≤ 15°), the underestimation was less than 7% (2.7 mm). The effect of abduction and adduction was negligible. CONCLUSION: For routine THA templating, an AP pelvis radiograph remains the gold standard. Only patients with femoral neck malrotation > 15° on the AP pelvis view, e.g. due to external rotation contracture, should receive further imaging. Options include an additional AP hip view with elevation of the entire affected hip to align the femoral neck more parallel to the detector, or a CT scan in more severe cases.Cite this article: Bone Jt Open 2022;3(10):795-803.

RESUMEN

BACKGROUND: Previous biomechanical studies simulating supination-external rotation (SER) IV injuries revealed different alterations in contact area and peak pressure. We investigated joint reaction forces and radiographic parameters in an unrestrained, more physiological setup. METHODS: Twelve lower leg specimens were destabilized stepwise by osteotomy of the fibula (SER II) and transection of the superficial (SER IVa) and the deep deltoid ligament (SER IVb) according to the Lauge-Hansen classification. Sensors in the ankle joint recorded tibio-talar pressure changes with axial loading at 700 N in neutral position, 10° of dorsiflexion, and 20° of plantarflexion. Radiographs were taken for each step. RESULTS: Three of 12 specimen collapsed during SER IVb. In the neutral position, the peak pressure and contact area changed insignificantly from 2.6 ± 0.5 mPa (baseline) to 3.0 ± 1.4 mPa (SER IVb) (P = .35) and from 810 ± 42 mm2 to 735 ± 27 mm2 (P = .08), respectively. The corresponding medial clear space (MCS) increased significantly from 2.5 ± 0.4 mm (baseline) to 3.9 ± 1.1 mm (SER IVb) (P = .028).The position of the ankle joint had a decisive effect on contact area (P = .00), center of force (P = .00) and MCS (P = .01). CONCLUSION: Simulated SER IVb injuries demonstrated radiological, but no biomechanical changes. This should be considered for surgical decision making based on MCS width on weightbearing radiographs. LEVELS OF EVIDENCE: Not applicable. Biomechanical study.

Asunto(s)

Fracturas de Tobillo , Articulación del Tobillo , Fracturas de Tobillo/diagnóstico por imagen , Fracturas de Tobillo/cirugía , Articulación del Tobillo/diagnóstico por imagen , Articulación del Tobillo/cirugía , Fenómenos Biomecánicos , Cadáver , Humanos , Ligamentos Articulares/diagnóstico por imagen , Ligamentos Articulares/lesiones , Ligamentos Articulares/cirugía , Supinación

RESUMEN

Background. Static weightbearing radiography can be used to assess stability in ankle fractures by measuring lateral talar shift (medial clear space; MCS). However, the correlation of a stable ankle joint under weightbearing load and the structural integrity of the deltoid ligament has not been shown. In this study, we assessed deltoid ligament integrity on magnetic resonance imaging (MRI) and correlated that with weightbearing and gravity stress test radiography. Methods. Thirty-four patients with supination external rotation II-IV (SER) fractures underwent MRI, weightbearing radiography, and gravity stress test. On MRI, the deep anterior and posterior tibiotalar deltoid, tibionavicular and tibiocalcaneal ligaments, as well as the syndesmosis were assessed as intact, partial rupture, or complete rupture. The MCS was measured as the distance between the lateral border of the medial malleolus and the medial border of the talus at the level of the talar dome on the mortise view. Results. Twenty-three patients suffered a deep anterior tibiotalar ligament rupture (16 partial; 7 complete) and 2 a deep posterior tibiotalar ligament tear (1 partial; 1 complete). For MCS on weightbearing radiography, no statistically significant differences were identified between any of the individual groups. With gravity stress radiography, only a complete tear of the tibiocalcaneal ligament showed a significantly higher MCS than a partial tear or intact tibiocalcaneal ligament (P < .005). No other ligament disruption showed a significant difference between the complete rupture versus intact or partial tear. Conclusion. Weightbearing radiography does not show much variation in terms of MCS even with ligamentous disruption and fibula fracture. The talus often centers itself underneath the tibia with weightbearing radiography.Levels of Evidence: Level III: Retrospective cohort study.

Asunto(s)

Fracturas de Tobillo , Fracturas de Tobillo/diagnóstico por imagen , Articulación del Tobillo/diagnóstico por imagen , Humanos , Ligamentos Articulares , Imagen por Resonancia Magnética , Radiografía , Estudios Retrospectivos , Soporte de Peso

RESUMEN

PURPOSE: The acetabular reinforcement ring with a hook (ARRH) has been designed for acetabular total hip arthroplasty (THA) revision. Additionally, the ARRH offers several advantages when used as a primary implant especially in cases with altered acetabular morphology. The implant facilitates anatomic positioning by placing the hook around the teardrop and provides a homogenous base for cementing the polyethylene cup. Therefore, the implant has been widely used in primary total hip arthroplasty at our institution. The present study reports the long-term outcome of the ARRH after a minimum follow-up of 20 years. METHODS: Two hundred and ten patients with 240 primary THAs performed between April 1987 and December 1991 using the ARRH were retrospectively reviewed after a minimum follow-up of 20 years. Twenty-three of 240 hips were lost to follow-up, 110 patients with 124 THAs had deceased without having a revision surgery performed. This left 93 hips for final evaluation. Of those, 75 hips were assessed clinically and radiographically after a mean follow-up of 23.1 years (range 21.1-26.1 years). In 18 cases, clinical and radiographic assessment was omitted because implant revision had been performed prior to the follow-up investigation. The primary endpoint was defined as revision for aseptic loosening. RESULTS: Out of the 93 hips available for final evaluation, 14 hips were revised for aseptic loosening; another four were revised for other reasons (deep infection n = 2, recurrent dislocation n = 2). The survival probability of the cup was 0.96 (95% confidence interval 0.93-0.99) after 20 years with aseptic loosening as endpoint. Radiographic analysis of the surviving 75 hips showed at least one sign of radiographic loosening in 24 hips. The mean Merle d'Aubigne score increased from 8 points pre-operatively to 15 points at final follow-up (7.5 ± 1.8 vs 15.0 ± 2.3, p < 0.001). The mean HHS was 85 ± 14 at final follow-up. Radiographic loosening did not correlate with the clinical outcome. CONCLUSIONS: The long-term results of the ARRH in primary THA are comparable to results with standard cemented cups and modern cementless cups. We believe that the ARRH is a versatile implant for primary THA, especially in cases with limited acetabular coverage and altered acetabular bone stock where the ARRH provides sufficient structural support for a cemented cup.

Asunto(s)

Acetábulo/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Cadera/métodos , Femenino , Estudios de Seguimiento , Prótesis de Cadera , Humanos , Masculino , Persona de Mediana Edad , Reoperación , Estudios Retrospectivos , Resultado del Tratamiento

RESUMEN

We present two cases of high tibial osteotomies performed at our institution. Both cases were complicated with the immediate postoperative occurrence of an ischaemic syndrome of the lower leg. Urgent diagnostics revealed a complete rupture of the popliteal artery that required re-operation and a vascular repair. Although neurovascular complications during high tibial osteotomies are rare the awareness of this potentially catastrophic complication should be present when performing this common procedure. All precautions to minimize the harm to the neurovascular bundle should be put into practice. A summary of the surgical precautions is presented and discussed in this paper.