Aims

Disorders of bone integrity carry a high global disease burden, frequently requiring intervention, but there is a paucity of methods capable of noninvasive real-time assessment. Here we show that miniaturized handheld near-infrared spectroscopy (NIRS) scans, operated via a smartphone, can assess structural human bone properties in under three seconds.

Aim. The primary endpoint of this study is to characterize the progression of bone defects at the femoral and tibial side in patients who sustained PJI of the knee that underwent two-stage revision with spacer implantation. In addition, we want to analyze the differences between functional moulded and hand-made spacers. Methods. A retrospective analysis of patients that underwent two-stage revision due to PJI of the knee between January 2014 and December 2021 at our institution. Diagnosis of infection was based on the criteria of the Muscoloskeletal Infection Society. The bone defect evaluation was performed intraoperatively based on the AORI classification. The basal evaluation was performed at the time the resection arthroplasty and spacer implantation surgery. The final evaluation was performed at the second-stage surgery, at the time of spacer removal and revision implant positioning. The differences between groups were characterized by using T-test student for continuous variables, and by using chi-square for categorical variables. A p-value < 0.05 was defined as significant. Results. Complete data of 37 two-stage TKAs revision were included in the study. An articulating moulded functional spacer was used in 14 (35.9%) cases, while a hand-made spacer was used in 23 (58.9%) cases. The average length of interval period (excluding the time for patients that retained the spacer) was 146.6 days. A bone defects progression based on the AORI classification was documented in 24 cases at the femoral side (61.6%), a bone defect progression was documented in 17 cases at the tibial side (43.6%), and a bone defect at both sides was documented in 13 cases (33.3%). A statistically significant greater bone defect progression at the tibial side was observed when hand-made spacers were used. A complication during the interval period was reported in five cases (12.8%) and postoperative complication was reported in 9 cases (23.1%). Conclusions. When comparing patients in which a functional articulating spacer was used, with patients in which static spacer was used, we reported a statistically significant reduced bone defect progression during the interval period at the femoral side only when moulded spacers were used. We observed a higher incidence of bone defect progression also at the tibial and both sides when hand-made spacers were used. This is the first study that documented the bone defect progression during two-stage revision of the knee, the results observed in this study are very encouraging

Aims. Chronic osteomyelitis may recur if dead space management, after excision of infected bone, is inadequate. This study describes the results of a strategy for the management of deep bone infection and evaluates a new antibiotic-loaded biocomposite in the eradication of infection from bone defects. Patients and Methods. We report a prospective study of 100 patients with chronic osteomyelitis, in 105 bones. Osteomyelitis followed injury or surgery in 81 patients. Nine had concomitant septic arthritis. 80 patients had comorbidities (Cierny-Mader (C-M) Class B hosts). Ten had infected nonunions. All patients were treated by a multidisciplinary team with a single-stage protocol including debridement, multiple sampling, culture-specific systemic antibiotics, stabilisation, dead space filling with the biocomposite and primary skin closure. . Results. Patients were followed up for a mean of 19.5 months (12 to 34). Infection was eradicated in 96 patients with a single procedure and all four recurrences were successfully managed with repeat surgery. Adverse events were uncommon, with three fractures, six wound leaks and three unrelated deaths. Outcome was not dependant on C-M host class, microbial culture, wound leakage or presence of nonunion. Conclusion. This single-stage protocol, facilitated by the absorbable local antibiotic, is effective in the treatment of chronic osteomyelitis. It offers a more patient-friendly treatment compared with other published treatment options. Cite this article: Bone Joint J 2016;98-B:1289–96

Purpose. It is generally accepted that the cement mantle surrounding the femoral component of a cemented total hip arthroplasty (THA) should be complete without any defects, and of at least 2 mm in thickness. Radiographic evaluation is the basis for assessment of the cement mantle. The adequacy of radiographic interpretation is subject to debate. Poor interobserver and intraobserver reproducibility of radiographic cement mantle assessment has been reported. In this study, 3D template software was used that allow anatomical measurements and analysis of three-dimensional digital femura geometry based on CT scans. The purpose of this study is to analyze the three-dimensional cement mantle thickness of cemented hip stem. Materials and Methods. 52 hips that underwent THA with Exeter stem (Stryker Orthopaedics, Mahwah, NJ) were enrolled in this study. All surgeries were performed by a single surgeon. There were 49 hips in 49 women and 3 hips in 3 men. The average age at surgery was 73 years (range, 60–88 years). The etiology of the hip lesions were osteoarthrosis in 49, rheumatoid arthritis in 3, and osteonecrosis of the femoral head in 1. For preoperative and postoperative evaluation, a CT scan of the pelvis and knee joint was obtained and was transferred to 3D template software (Zed hip, Lexi, Tokyo, Japan). We evaluated the alignment for stem anteversion/valgus/anterior tilt angles and the contact of the cortical bone with the cement mantle was evaluated. Results. Concerning the alignment of the stems, variability was observed in the anteversion; however, the stems were inserted in an almost neutral position in varus-valgus and extension-flexion. The 3D contact of the stems with a cement mantle of 2 mm added with the cortical bone was evaluated, and it could be broadly classified into three patterns: cases in which the cortical bone was not reamed in the range of 2 mm from the stem, those in which the distal medial part was partially reamed, and cases in which the distal anterior and medial parts of the cortical bone were reamed in a relatively wide range. In this study, there were 17 patients with no reaming, 32 patients with partial reaming, and 3 patients with a relatively large range of reaming. Discussion and Conclusion. Oversizing of the stem associated with incomplete cement mantles has been suggested to account for early femoral component loosening. In this study, 3 patients whose cortical bone was reamed in a relatively wide range and who had a risk of partial thinning of the cement mantle as a result were observed. The effect of reaming of the cortical bone on the clinical results is still unknown; however, a careful follow-up in the future may be required

Backgrounds. Most of in vivo kinematic studies of total knee arthroplasty (TKA) have reported on varus knee. TKA for the valgus knee deformity is a surgical challenge. The purposes of the current study are to analyze the in vivo kinematic motion and to compare kinematic patterns between weight-bearing (WB) and non-weight-bearing (NWB) knee flexion in posterior-stabilized (PS) fixed-bearing TKA with pre-operative valgus deformity. Methods. A total of sixteen valgus knees in 12 cases that underwent TKA with Scorpio NRG PS knee prosthesis operated by modified gap balancing technique were evaluated. The mean preoperative femorotibial angle (FTA) was 156°±4.2°. During the surgery, distal femur and proximal tibia was cut perpendicular to the mechanical axis of each bone. After excision of the menisci and cruciate ligaments, balancer (Stryker joint dependent kinematics balancer) was inserted into the gap between both bones for evaluation of extension gap. Lateral release was performed in extension. Iliotibial bundle (ITB) was released from Gerdy tubercle then posterolateral capsule was released at the level of the proximal tibial cut surface. If still unbalanced, pie-crust ITB from inside-out was added at 1 cm above joint line until an even lateral and medial gap had been achieved. Flexion gap balance was obtained predominantly by the bone cut of the posterior femoral condyle. Good postoperative stability in extension and flexion was confirmed by stress roentgenogram and axial radiography of the distal femur. We evaluated the in vivo kinematics of the knee using fluoroscopy and femorotibial translation relative to the tibial tray using a 2-dimentional to 3-dimensional registration technique. Results. The average flexion angle was 111.3°±7.5° in weight-bearing and 114.9°±8.4° in non-weight-bearing. The femoral component demonstrated a mean external rotation of 5.9°±5.8° in weight-bearing and 7.4°±5.2° in non-weight-bearing (Fig.1). In weight-bearing, the femoral component showed medial pivot pattern from 0° to midflexion and a bicondylar rollback pattern from midflexion to full flexion (Fig2). Medial condyle moved similarly in non-weight-bearing condition and in weight-bearing condition. Lateral condyle moved posterior in slightly earlier angle during weight-bearing condition than during non-weight-bearing condition (Fig.3). Discussion. Numerous kinematic analyses of a normal knee have demonstrated greater posterior motion of the lateral femoral condyle relative to the medial condyle, leading to a mean external rotation and a bicondylar rollback motion with progressive knee flexion. A kinematic analysis of valgus knee was reported to show a different kinematic pattern from a physiological knee motion. Many valgus knees showed paradoxical anterior translation from extension to mid-flexion and greater posterior translation in the medial condyle than in the lateral condyle. Kitagawa et al. reported that this non-physiologic pattern wasn't completely restored after TKA using medial pivot knee system. In the present study, we showed kinematic patterns of the TKA performed on the valgus knee to be similar to the normal knee for the first time, even though the magnitude of external rotation was small. Conclusions. We conclude that the medial pivot pattern followed by posterior rollback motion can be obtained in TKA with modified gap balancing technique for the preoperative valgus deformity

In cases of poor bone quality intraoperative torque measurement might be an alternative to preoperative dual energy x-ray absorptiometry (DXA) to assess bone quality in Total Hip Arthroplasty (THA). 14 paired fresh frozen human femurs were included for trabecular peak torque measurement. We evaluated an existing intraoperative torque measurement method to assess bone quality and bone strength. We modified the approach to use this method in total hip arthroplasty (THA), which has not been published before. Since there are several approaches used in THA to exposure the hip joint, we decided to prefer the measurement in the femoral head which allows every surgeon to perform this measurement. Here a 6.5 × 23 mm blade was inserted into the proximal femur without harming the lateral cortical bone (figure 1). Further tests of the proximal femur evaluated the results of this new method: DXA, micro-computed tomography (μCT) and biomechanical load tests. Basic statistical analyses and multiple regressions were done. In the femoral head mean trabecular peak torque was 4.38 ± 1.86 Nm. These values showed a strong correlation with the values of the DXA, the μCT and the biomechanical load test. In comparison to the bone mineral density captured by DXA, the results of the intraoperative torque measurement showed a superior correlation with high sensitive bone quality evaluating methods (mechanical load tests and micro-computed tomography). Hence, the use of this intraoperative torque measurement seems to be more accurate in evaluating bone strength and bone quality than DXA during THA. The torque measurement provides sensitive information about the bone strength, which may affect the choice of implant in cases of poor bone stock and osteoporosis. In clinical use the surgeon may alter the prosthesis if the device indicates poor bone quality. Furthermore, we assume that the disadvantages associated with DXA scans like radiation exposure or errors caused by potential extraosteal sclerosis and interindividual soft-tissue artifacts could be excluded