Primary stability of multi-hole acetabular cup combined with posterior column plating for the fixation of complex acetabular fractures in elderly patients: a biomechanical analysis.

BACKGROUND: Acute total hip arthroplasty has gained increasing popularity in the treatment of complex acetabular fractures in elderly patients, but the biomechanical evidence is lacking. Therefore, we measured the primary stability to evaluate whether acute total hip arthroplasty using a multi-hole acetabular cup and posterior column plating through a single K-L approach can safely be used for treating complexed acetabular fractures in the elderly. METHODS: In 18 composite osteoporotic hemipelves, T-type acetabular fractures were treated in three ways: CSP (Cup with acetabular screws augmentation combined with posterior plate) group, CP (Cup without acetabular screw combined with posterior plate) group and CSPA (Cup with acetabular screws combined with posterior plate and anterior plate) group. Each specimen was dynamically loaded (300 to 1700 N, 1 Hz). Primary stability of the acetabular cup and fracture gap was evaluated by 3-dimensional (3D) micromotions. RESULTS: No significant differences in the 3D-micromotions were observed among the CSP, CP and CSPA groups except the test point on the anterior column of the acetabulum in the CP scenario (CSP 49.33 ± 21.08 µm vs. CP 224.83 ± 52.29 µm, p < 0.001; CSPA 45.50 ± 12.16 µm vs. CP 224.83 ± 52.29 µm, p < 0.001). No significant differences in the fracture gap displacement on the posterior column of acetabulum were observed among the CSP, CP and CSPA groups. CONCLUSION: Our results show, that acute total hip arthroplasty using a multi-hole cup with acetabular screws and posterior column plating through single a K-L approach offers good primary stability to allow good osseous integration for treating complex acetabular fractures in the elderly. Furthermore, it also provides good fracture gap displacement on the posterior column.

Management of comminuted inferior patellar pole fractures with cerclage-wire-augmented separate vertical wiring: a retrospective clinical study.

PURPOSE: Comminuted inferior patellar pole fractures are challenging injuries and require effective treatment due to the extension mechanism of the knee. This study aims to evaluate the outcome of above fractures treated with a modified technique of cerclage-wire-augmented separate vertical wiring (SVW) with cerclage wiring passed through the proximal patella. METHODS: Retrospective analysis (1/2017-1/2020) were performed for patients that were treated with three SVWs through the posterior margin of proximal fragment and directly to the anterosuperior border of patella, combined with a cerclage wiring passed through the proximal patella. Patients who experienced comminuted inferior patellar pole fractures within 3 weeks were included, and the outcome was evaluated radiologically and clinically by Bostman score after a minimum of 12 months following surgery. Further evaluation included the operation time and complication rate. RESULTS: A total of 20 patients (10 males, 10 females) with a mean age of 54 ± 14.5 years (26-83 years) and a follow-up of 18.9 ± 6.6 months (12-36 months) were evaluated. The average operation time was 45.7 ± 8.8 min (30-60 min). At final follow-up, the average range of motion was 131.3° ± 3.5° (125°-135°), and the mean Bostman score was 29.4 ± 0.7 points (28-30) and graded excellent in all cases. Two patients experienced occasional giving way of the knee. Radiologically no loss of reduction, implant breakage, nonunion or skin irritation was observed. CONCLUSIONS: The cerclage-wire-augmented SVW with cerclage wiring passed through the proximal patella appears to be a safe and simple technique which can effectively treat the comminuted inferior patellar pole fractures.

Suprapatellar versus infrapatellar approaches in the treatment of tibia intramedullary nailing: a retrospective cohort study.

BACKGROUND: Tibial shaft fractures are routinely managed with intramedullary nailing (IMN). An increasingly accepted technique is the suprapatellar (SP) approach. The purpose of this study was to compare the clinical and functional outcomes of knee joint after tibia IMN through an suprapatellar (SP) or traditional infrapatellar (IP) approach. METHODS: Retrospective analysis was performed in patients with tibial shaft fractures that were treated with IMN through a SP or IP approach between 01/01/2014 and 31/12/2016. The clinical and functional outcomes of the knee were assessed with the Hospital for Special Surgery (HSS) Knee Score. Secondary outcomes included the operation time and intraoperative blood loss. RESULTS: A total of 50 patients/fractures (26 IP and 24 SP) with a minimum follow-up of 15 months were evaluated. All fractures were OTA 42. No significant differences were found between the two groups in age, gender, side of fractures, operation time, intra-operative blood loss, and follow-up time. No significant difference was seen in HSS score (P = 0.62) between them. Sub analysis of all the HSS components scores revealed no significant differences between pain (P = 0.57), the stand and walk (P = 0.54), the need for walking stick (P = 0.60) and extension lag (P = 0.60). The other HSS components showed full scores (IP 10 vs. SP 10) in both approaches, including muscle force, flexion deformity and stability components. The range of motion (ROM) component score was superior in the IP group (P = 0.04) suggesting a higher ROM. CONCLUSIONS: Both SP and IP approach results in equivalent overall HSS knee scores. However, for the HSS component, the IP approach was superior to SP approach regarding the ROM.

Minimally invasive internal fixator for unstable pelvic ring injuries with a pedicle screw-rod system: a retrospective study of 23 patients after 13.5 months.

PURPOSE: Pelvic ring fractures are challenging injuries and require effective treatment due to the frequently compromised patient condition. The aim of this study was to evaluate the outcome of unstable pelvic ring injuries treated with a minimally invasive pedicle screw-rod system. METHODS: Retrospective analysis was performed for patients with an unstable pelvic ring injury that were treated with a minimally invasive anterior internal pelvic fixator (INFIX) with or without a posterior pedicle screw-rod fixator (6/2012-4/2015). The quality of reduction was evaluated by the Tornetta and Matta criteria and the clinical outcome was evaluated by the Majeed scores. Further evaluation included the operation time, intraoperative blood loss, and complication rate. RESULTS: A total of 23 patients (12 males and 11 females) with a mean age of 37.6 years (range 10-65 years) and a follow-up of 13.5 months (6-27 months) were evaluated. The Tile classification showed 13 type B (B1 = 6, B2 = 4, and B3 = 3) and 10 type C (C1 = 7 and C2 = 3) fractures. Mean operation time and intraoperative blood loss were 24.8 min (20-30 min) and 20.4 ml (16-29 ml) for an anterior INFIX (n = 13), and 60 min (45-70 min) and 150 ml (115-168 ml) when combined with a posterior pedicle screw-rod fixator (n = 10). Quality of reduction was excellent in 13, good in 6, and fair in 4 patients, with no signs of heterotopic ossification. Clinical results after 6 months were excellent in 14 patients, good in 6, fair in 2, and poor in 1. Unilateral thigh paresthesia was seen in 2 patients which resolved after implant removal. CONCLUSIONS: The INFIX appears to be a safe and minimally invasive surgical technique which can effectively be combined with posterior pedicle screw-rod fixation. It also can be applied for the definitive treatment of vertically and/or rotationally unstable pelvic ring injuries, especially in severely compromised patients with a high mortality risk.

Periprosthetic bone remodelling of short-stem total hip arthroplasty: a systematic review.

PURPOSE: Short-stem hip arthroplasty (SHA) was designed to preserve bone stock and provide an improved load transfer. To gain more evidence regarding the load transfer, this review analysed the periprosthetic bone remodelling of SHA in comparison to standard hip arthroplasty (THA). METHODS: PubMed and ScienceDirect were screened to extract dual-energy X-ray absorptiometry (DXA) studies evaluating the periprosthetic bone remodelling of SHA and two proven THA designs. From the studies included, the postoperative change in periprosthetic bone mineral density (BMD) after one year and the trend over two years was determined. RESULTS: Fifteen studies with four SHAs (CFP, Metha, Nanos, Fitmore) and two THAs (CLS and Bicontact) designs were included. All SHA and THA stems revealed an initial decrease at the calcar and major trochanter (Gruen 1 and 7) with the Metha, Nanos and Fitmore showing a smaller and more balanced remodelling compared to THA. The pattern after one year and the trend over two years argue for a methaphyseal anchorage of the Metha and Nanos, whereas the Fitmore and CFP seem to anchor metha-diaphyseal. Clearly different pattern of bone remodelling were observed between all four SHAs. CONCLUSIONS: Periprosthetic bone remodelling is also present in SHA, with the main bone reduction observed proximally. However, certain SHA stems show a more balanced remodelling compared to THA, arguing for a favourable load transfer. Also, the femoral length where bone remodelling occurs is clearly shorter in SHA. As distinctively different pattern between the SHA designs were observed, they should not be judged as a single implant group.

Can the metaphyseal anchored Metha short stem safely be revised with a standard CLS stem? A biomechanical analysis.

PURPOSE: Short stem total hip arthroplasty (SHA) has gained increasing popularity as it conserves bone stock and is supposed to allow revision with a conventional stem. However, no study has evaluated whether the revision of a SHA with a standard total hip arthroplasty (THA) stem provides sufficient primary stability to allow osseous integration. METHODS: A neck preserving SHA (Metha) and a standard THA (CLS) stem were implanted into six composite femurs respectively and dynamically loaded (300-1700 N, 1 Hz). Primary stability was evaluated by three dimensional-micromotions (3D micro motion) at five points of the interface. Then, a revision scenario was created by removing the SHA and using the same CLS stem as a revision implant (CLS-revision group), with subsequent evaluation of the 3D micro motion according to the primary CLS stem. RESULTS: The 3D micro motion pattern significantly differed in the primary situation between the short and the standard stem. The highest 3D micro motion were registered proximally for the Metha and distally for the CLS stem. Revising the Metha with a CLS stem revealed a bony defect at the calcar. However, the 3D micro motion of the CLS-revision group were not significant higher compared to those of the primary CLS stem. CONCLUSION: Our results show, that SHA (Metha) and standard THA (CLS) provide a good primary stability, however with different pattern of anchorage. The CLS stem reached a similar stability in this revision scenario as the CLS in the primary situation, wherefore it can be assumed that in uncomplicated revisions the Metha short stem can safely be revised with a CLS standard stem.

Femoral Neck System versus Three Cannulated Screws for Fixation of Femoral Neck Fractures in Younger Patients: A Retrospective Cohort Study.

OBJECTIVE: To compare the clinical results of a new femoral neck system (FNS) and cannulated compression screws (CCS) for the treatment of femoral neck fractures in younger patients. METHODS: Retrospective study was performed in younger patients with femoral neck fractures that were treated with FNS or CCS from August 2017 to August 2022. The hip functional outcomes were assessed with the Harris hip score (HHS). Secondary outcomes included the surgical time, surgical blood loss, satisfaction visual analog scale (VAS), fluoroscopy frequency, fracture healing time and complications. RESULTS: A total of 49 patients (22 FNS and 27 CCS) with a minimum follow-up of 12 months were included. There was also no significant difference in HHSs (p = 0.27) and satisfaction VAS (p = 0.10) between them. Patients with FNS had more blood loss (50.45 ± 5.28 mL vs. 20.67 ± 4.71 ml, p < 0.01), lower fluoroscopy frequency (16.64 ± 3.32 vs. 23.59 ± 3.39, p < 0.01) and lower fracture healing time (3.76 ± 0.42 vs. 4.46 ± 0.59 months, p < 0.01). The femoral neck shortening and incidence of nail withdrawal in the FNS group was significantly lower than CCS group (2.91 ± 1.95 vs. 4.44 ± 1.52 mm, p < 0.01; 4.5% vs. 22.2%, p = 0.03). CONCLUSIONS: The FNS and CCS get similar hip functions. The FNS can reduce fluoroscopy exposure and the complications such as femoral neck shortening and nail withdrawal. Thus, FNS can be an alternative to CCS for the fixation of femoral neck fractures in younger patients.

Cortical bone thickness of the distal radius predicts the local bone mineral density.

AIMS: The distal radius is a major site of osteoporotic bone loss resulting in a high risk of fragility fracture. This study evaluated the capability of a cortical index (CI) at the distal radius to predict the local bone mineral density (BMD). METHODS: A total of 54 human cadaver forearms (ten singles, 22 pairs) (19 to 90 years) were systematically assessed by clinical radiograph (XR), dual-energy X-ray absorptiometry (DXA), CT, as well as high-resolution peripheral quantitative CT (HR-pQCT). Cortical bone thickness (CBT) of the distal radius was measured on XR and CT scans, and two cortical indices mean average (CBTavg) and gauge (CBTg) were determined. These cortical indices were compared to the BMD of the distal radius determined by DXA (areal BMD (aBMD)) and HR-pQCT (volumetric BMD (vBMD)). Pearson correlation coefficient (r) and intraclass correlation coefficient (ICC) were used to compare the results and degree of reliability. RESULTS: The CBT could accurately be determined on XRs and highly correlated to those determined on CT scans (r = 0.87 to 0.93). The CBTavg index of the XRs significantly correlated with the BMD measured by DXA (r = 0.78) and HR-pQCT (r = 0.63), as did the CBTg index with the DXA (r = 0.55) and HR-pQCT (r = 0.64) (all p < 0.001). A high correlation of the BMD and CBT was observed between paired specimens (r = 0.79 to 0.96). The intra- and inter-rater reliability was excellent (ICC 0.79 to 0.92). CONCLUSION: The cortical index (CBTavg) at the distal radius shows a close correlation to the local BMD. It thus can serve as an initial screening tool to estimate the local bone quality if quantitative BMD measurements are unavailable, and enhance decision-making in acute settings on fracture management or further osteoporosis screening. Cite this article: Bone Joint Res 2021;10(12):820-829.

Cortical bone thickness predicts the quantitative bone mineral density of the proximal humerus.

Cortical thickness determined at the humerus can serve as an easy and reliable screening tool to predict the local bone status when quantitative bone mineral density (BMD) measurements are not available. It can therefore serve as a rapid screening tool in fragility fractures to identify patients requiring further diagnostic or osteoporosis treatment. INTRODUCTION: Quantitative bone mineral density (BMD) of the humerus is difficult to determine but relevant for osteoporosis and fracture treatment. Dual-energy X-ray absorptiometry (DXA) of the femur and lumbar spine overestimates the humeral BMD and is not ubiquitously available. Therefore, this study evaluated whether the cortical bone thickness (CBT) of the humerus or DXA of the forearm is able to predict humeral BMD. METHODS: Humeral BMD of 54 upper cadaver extremities (22 pairs, 10 single) (19-90 years) was determined by high-resolution peripheral-quantitative-computed-tomography (HR-pQCT) (volumetric BMD (vBMD)) and DXA (areal BMD (aBMD)) of the proximal humerus and distal forearm. Average and gauge cortical bone thickness (CBTavg/ CBTg) of the humeral diaphysis was determined from standard radiographs (XR) and computed-tomography (CT) and compared to the humeral BMD. Pearson (r) and intraclass-correlation-coefficients (ICC) were used to compare results and rater-reliability. RESULTS: CBTavg from XR strongly correlated with the humeral BMD (r = 0.78 aBMD (DXA) and r = 0.64 vBMD (HR-pQCT) (p < 0.0001)). The CBTg revealed a weaker correlation (r = 0.57 aBMD and r = 0.43 vBMD). CBT derived from XR strongly correlated to those from the CT (r = 0.82-0.90) and showed an excellent intra- and inter-rater correlation (ICC 0.79-0.92). Distal forearm aBMD correlated well with the humeral aBMD (DXA) (r = 0.77) and paired specimens highly correlated to the contralateral side (humerus r = 0.89, radius r = 0.97). CONCLUSIONS: The CBTavg can reliably be determined from standard radiographs and allows a good prediction of quantitative humeral bone mineral density (aBMD or vBMD) if measurements are not available. Furthermore, the distal forearm or the contralateral humerus can serve as a side to estimate the BMD if the ipsilateral side is impaired.

Metaphyseal anchoring short stem hip arthroplasty provides a more physiological load transfer: a comparative finite element analysis study.

BACKGROUND: Short stem total hip arthroplasty (SHA) preserves femoral bone stock and is supposed to provide a more natural load transfer compared to standard stem total hip arthroplasty (THA). As comparative biomechanical reference data are rare we used a finite element analysis (FEA) approach to compare cortical load transfer after implantations of a metaphyseal anchoring short and standard stem in native biomechanical femora. METHODS: The subject specific finite element models of biomechanical femora, one native and two with implanted metaphyseal anchoring SHA (Metha, B. Braun Aesculap) and standard THA (CLS, Zimmer-Biomet), were generated from computed tomography datasets. The loading configuration was performed with an axial force of 1400 N. Von Mises stress was used to investigate the change of cortical stress distribution. RESULTS: Compared to the native femur, a considerable reduction of cortical stress was recorded after implantation of SHA and standard THA. The SHA showed less reduction proximally with a significant higher metaphyseal cortical stress compared to standard THA. Moreover, the highest peak stresses were observed metaphyseal for the SHA stem while for the standard THA high stress pattern was observed more distally. CONCLUSIONS: Both, short and standard THA, cause unloading of the proximal femur. However, the metaphyseal anchoring SHA features a clearly favorable pattern in terms of a lower reduction proximally and improved metaphyseal loading, while standard THA shows a higher proximal unloading and more distal load transfer. These load patterns implicate a reduced stress shielding proximally for metaphyseal anchoring SHA stems and might be able to translate in a better bone preservation.

Periprosthetic bone remodeling of short cementless femoral stems in primary total hip arthroplasty: A systematic review and meta-analysis of randomized-controlled trials.

BACKGROUND: Short-stem total hip arthroplasty (SHA) has been increasingly used in the treatment of hip arthroplasty. However, it is unclear whether there is a superiority of SHA in periprosthetic bone remodeling over standard stem total hip arthroplasty (THA). This meta-analysis of randomized-controlled trials (RCTs) compared the periprosthetic bone remodeling after SHA and THA. METHODS: PubMed and Embase were screened for relevant publications up to May 2017. RCTs that compared periprosthetic bone remodeling with bone mineral density (BMD) changes between SHA and THA were included. Meta-analysis was conducted to calculate weighted mean differences (WMDs) and 95% confidence intervals (CIs) using Stata version 12.0. Quality appraisal was performed by 2 independent reviewers using RevMan 5.3 software and Grades of Recommendation Assessment, Development, and Evaluation criteria. RESULTS: Seven studies involving 910 patients and 5 SHA designs (Proxima, Fitmore, Microplasty short, Unique custom, and Omnifit-HA 1017) were included for meta-analysis. The pooled data showed no significant differences in the percentage BMD changes in all Gruen zones, with Gruen zone 1 [mean difference (MD) = 11.33, 95% CI, -1.67 to 24.33; P = .09] and Gruen zone 7 (MD = 8.46, 95% CI, -1.73 to 18.65; P = .10). Subgroup analysis of short SHA stems with lateral flare showed a significant less percentage BMD changes compared with standard THA in Gruen zone 1 (MD = 27.57, 95% CI, 18.03-37.12; P < .0001) and Gruen zone 7 (MD = 18.54, 95% CI, 8.27-28.81; P < .0001). CONCLUSION: The study shows moderate-quality evidence that periprosthetic bone remodeling around the analyzed SHA stems was similar to standard THA stems. However, short SHA stems with lateral flare revealed a moderate- to low-quality evidence for superiority over the standard THA and highlighted the importance of the different SHA designs. Besides, it has to be noticed that despite a similar pattern of periprosthetic bone remodeling, the femoral length where periprosthetic bone remodeling occurs is clearly shorter in SHA. Due to the moderate- to low-quality evidence and the limited stem designs analyzed, the further large-scale multicenter RCTs including the most recent SHA designs are required. However, the current findings should be considered by surgeons for counseling patients regarding total hip replacement.