Aims. The aim of this study was to determine the stability of a new short femoral stem compared with a conventional femoral stem in patients undergoing cementless total hip arthroplasty (THA), in a prospective randomized controlled trial using radiostereometric analysis (RSA). Patients and Methods. A total of 53 patients were randomized to receive cementless THA with either a short femoral stem (MiniHip, 26 patients, mean age: 52 years, nine male) or a conventional length femoral stem (MetaFix, 23 patients, mean age: 53 years, 11 male). All patients received the same cementless acetabular component. Two-year follow-up was available on 38 patients. Stability was assessed through migration and dynamically inducible micromotion. Radiographs for RSA were taken postoperatively and at three, six, 12, 18, and 24 months. Results. At two years, there was significantly less subsidence (inferior migration) of the short femoral stem (head, 0.26 mm, 95% confidence interval (CI) 0.08 to 0.43, . sd. 0.38; tip, 0.11 mm, 95% CI -0.08 to 0.31, . sd. 0.42) compared with the conventional stem (head, 0.62 mm, 95% CI 0.34 to 0.90, . sd. 0.56, p = 0.02; tip, 0.43 mm, 95% CI 0.21 to 0.65, . sd. 0.44, p = 0.03). There was no significant difference in dynamically inducible micromotion, rate of complications or functional outcome. Conclusion. This study demonstrates that the short femoral stem has a stable and predictable migration. However, longer-term survival analysis still needs to be determined. Cite this article: Bone Joint J 2018;100-B:1148–56

Aims. Optimal exposure through the direct anterior approach (DAA) for total hip arthroplasty (THA) conducted on a regular operating theatre table is achieved with a standardized capsular releasing sequence in which the anterior capsule can be preserved or resected. We hypothesized that clinical outcomes and implant positioning would not be different in case a capsular sparing (CS) technique would be compared to capsular resection (CR). Methods. In this prospective trial, 219 hips in 190 patients were randomized to either the CS (n = 104) or CR (n = 115) cohort. In the CS cohort, a medial based anterior flap was created and sutured back in place at the end of the procedure. The anterior capsule was resected in the CR cohort. Primary outcome was defined as the difference in patient-reported outcome measures (PROMs) after one year. PROMs (Harris Hip Score (HHS), Hip disability and Osteoarthritis Outcome Score (HOOS), and Short Form 36 Item Health Survey (SF-36)) were collected preoperatively and one year postoperatively. Radiological parameters were analyzed to assess implant positioning and implant ingrowth. Adverse events were monitored. Results. At one year, there was no difference in HSS (p = 0.728), HOOS (Activity Daily Life, p = 0.347; Pain, p = 0.982; Quality of Life, p = 0.653; Sport, p = 0.994; Symptom, p = 0.459), or SF-36 (p = 0.338). Acetabular component inclination (p = 0.276) and anteversion (p = 0.392) as well as femoral component alignment (p = 0.351) were similar in both groups. There were no dislocations, readmissions, or reoperations in either group. The incidence of psoas tendinitis was six cases in the CS cohort (6%) and six cases in the CR cohort (5%) (p = 0.631). Conclusion. No clinical differences were found between resection or preservation of the anterior capsule when performing a primary THA through the DAA on a regular theatre table. In case of limited visibility during the learning curve, it might be advisable to resect a part of the anterior capsule. Cite this article: Bone Joint J 2021;103-B(2):321–328

Aims. Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity. Methods. A total of eight cadaveric lower limb pairs were arbitrarily assigned to either 1) isolated lateral plating, or 2) lateral and medial plating of the distal femur, with four specimens per group. Contralateral limbs served as matched controls. Pre- and post-contrast MRI was performed to quantify signal intensity enhancement in the distal femur. Further evaluation of intraosseous vascularity was done with barium sulphate infusion with CT scan imaging. Specimens were then injected with latex medium and dissection was completed to assess extraosseous vasculature. Results. Quantitative MRI revealed a mean reduction of 21.2% (SD 1.3%) of arterial contribution in the lateral plating group and 25.4% (SD 3.2%) in the dual plating group (p = 0.051); representing a mean decrease in arterial contribution of 4.2%. The only significant difference found between both experimental groups was regionally, at the lateral aspect of the distal femur with a mean drop in arterial contribution in the lateral plating group of 18.9% (SD 2.6%) versus 24.0% (SD 3.2%) in the dual plating group (p = 0.048), representing a mean decrease in arterial contribution of 5.1%. Gross dissection revealed complete destruction of periosteal vessels underneath either medial or lateral plates in both groups. The network of genicular branches contributing to the posterior and distal femoral condyles was preserved in all specimens. A medial vascular pedicle was found dividing from the superficial femoral artery at a mean 12.7 cm (SD 1.7) proximal to the medial epicondyle and was undisrupted in the dual plating group. Conclusion. Lateral locking-plate application resulted in mean 21.2% reduction in distal femur vascularity. Addition of medial plates did not further markedly decrease vascularity. As such, the majority of the vascular insult occurred with lateral plating alone. Supplemental medially based fixation did not lead to marked devascularization of the distal femur, and should therefore be considered in the setting of comminution and poor bone stock in distal femoral fractures. Further clinical research is required to confirm the results of this study. Cite this article: Bone Joint J 2020;102-B(4):530–538

Aims. The aim of this study was to determine whether fixation, as opposed to revision arthroplasty, can be safely used to treat reducible Vancouver B type fractures in association with a cemented collarless polished tapered femoral stem (the Exeter). Methods. This retrospective cohort study assessed 152 operatively managed consecutive unilateral Vancouver B fractures involving Exeter stems; 130 were managed with open reduction and internal fixation (ORIF) and 22 with revision arthroplasty. Mean follow-up was 6.5 years (SD 2.6; 3.2 to 12.1). The primary outcome measure was revision of at least one component. Kaplan–Meier survival analysis was performed. Regression analysis was used to identify risk factors for revision following ORIF. Secondary outcomes included any reoperation, complications, blood transfusion, length of hospital stay, and mortality. Results. Fractures (B1 n = 74 (49%); B2 n = 50 (33%); and B3 n = 28 (18%)) occurred at median of 4.2 years (interquartile range (IQR) 1.2 to 9.2) after primary total hip arthroplasty (THA) (n = 138) or hemiarthroplasty (n = 14). Rates of revision and reoperation were significantly higher following revision arthroplasty compared to ORIF for B2 (p = 0.001) and B3 fractures (p = 0.050). Five-year survival was significantly better following ORIF: 92% (95% confidence interval (CI) 86.4% to 97.4%) versus 63% (95% CI 41.7% to 83.3%), p < 0.001. ORIF was associated with reduced blood transfusion requirement and reoperations, but there were no differences in medical complications, hospital stay, or mortality between surgical groups. No independent predictors of revision following ORIF were identified: where the bone-cement interface was intact, fixation of B2 or B3 fractures was not associated with an increased risk of revision. Conclusion. When the bone-cement interface was intact and the fracture was anatomically reducible, all Vancouver B fractures around Exeter stems could be managed with fixation as opposed to revision arthroplasty. Fixation was associated with reduced need for blood transfusion and lower risk of revision surgery compared with revision arthroplasty. Cite this article: Bone Joint J 2021;103-B(2):309–320

Aims. Altered alignment and biomechanics are thought to contribute to the progression of osteoarthritis (OA) in the native compartments after medial unicompartmental knee arthroplasty (UKA). The aim of this study was to evaluate the bone activity and remodelling in the lateral tibiofemoral and patellofemoral compartment after medial mobile-bearing UKA. Patients and Methods. In total, 24 patients (nine female, 15 male) with 25 medial Oxford UKAs (13 left, 12 right) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively and at one and two years postoperatively, along with standard radiographs and clinical outcome scores. The mean patient age was 62 years (40 to 78) and the mean body mass index (BMI) was 29.7 kg/m2 (23.6 to 42.2). Mean osteoblastic activity was evaluated using a tracer localization scheme with volumes of interest (VOIs). Normalized mean tracer values were calculated as the ratio between the mean tracer activity in a VOI and background activity in the femoral diaphysis. Results. Significant reduction of normalized tracer activity was observed one year postoperatively in tibial and femoral VOIs adjacent to the joint line in the lateral compartment. Patellar VOIs and remaining femoral VOIs demonstrated a significant, diminished normalized tracer activity at final follow-up. Conclusion. The osteoblastic bone activity in the native compartments decreased significantly after treatment of medial end-stage OA with a UKA, implying reduced stress to the subchondral bone in the retained compartments after a UKA. Cite this article: Bone Joint J 2019;101-B:915–921

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Osteoarticular reconstruction of the distal femur in childhood has the advantage of preserving the tibial physis. However, due to the small size of the distal femur, matching the host bone with an osteoarticular allograft is challenging. In this study, we compared the outcomes and complications of a resurfaced allograft-prosthesis composite (rAPC) with those of an osteoarticular allograft to reconstruct the distal femur in children.

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Dislocation of the hip remains a major complication after periacetabular tumour resection and endoprosthetic reconstruction. The position of the acetabular component is an important modifiable factor for surgeons in determining the risk of postoperative dislocation. We investigated the significance of horizontal, vertical, and sagittal displacement of the hip centre of rotation (COR) on postoperative dislocation using a CT-based 3D model, as well as other potential risk factors for dislocation.

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The primary aim of this study was to determine the ten-year outcome following surgical treatment for femoroacetabular impingement (FAI). We assessed whether the evolution of practice from open to arthroscopic techniques influenced outcomes and tested whether any patient, radiological, or surgical factors were associated with outcome.

Aims. This study aims to investigate the effects of posterior tibial slope (PTS) on knee kinematics involved in the post-cam mechanism in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) using computer simulation. Methods. In total, 11 different PTS (0° to 10°) values were simulated to evaluate the effect of PTS on anterior post-cam contact conditions and knee kinematics in BCS TKA during weight-bearing stair climbing (from 86° to 6° of knee flexion). Knee kinematics were expressed as the lowest points of the medial and lateral femoral condyles on the surface of the tibial insert, and the anteroposterior translation of the femoral component relative to the tibial insert. Results. Anterior post-cam contact in BCS TKA was observed with the knee near full extension if PTS was 6° or more. BCS TKA showed a bicondylar roll forward movement from 86° to mid-flexion, and two different patterns from mid-flexion to knee extension: screw home movement without anterior post-cam contact and bicondylar roll forward movement after anterior post-cam contact. Knee kinematics in the simulation showed similar trends to the clinical in vivo data and were almost within the range of inter-specimen variability. Conclusion. Postoperative knee kinematics in BCS TKA differed according to PTS and anterior post-cam contact; in particular, anterior post-cam contact changed knee kinematics, which may affect the patient’s perception of the knee during activities. Cite this article: Bone Joint Res 2020;9(11):761–767

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The aim of this systematic review and meta-analysis was to gather epidemiological information on selected musculoskeletal injuries and to provide pooled injury-specific incidence rates.

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Accurate identification of the ankle joint centre is critical for estimating tibial coronal alignment in total knee arthroplasty (TKA). The purpose of the current study was to leverage artificial intelligence (AI) to determine the accuracy and effect of using different radiological anatomical landmarks to quantify mechanical alignment in relation to a traditionally defined radiological ankle centre.

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In the last decade, perioperative advancements have expanded the use of outpatient primary total knee arthroplasty (TKA). Despite this, there remains limited data on expedited discharge after revision TKA. This study compared 30-day readmissions and reoperations in patients undergoing revision TKA with a hospital stay greater or less than 24 hours. The authors hypothesized that expedited discharge in select patients would not be associated with increased 30-day readmissions and reoperations.

Aims. Our purpose was to describe an unusual series of 21 patients with fungal osteomyelitis after an anterior cruciate ligament reconstruction (ACL-R). Methods. We present a case-series of consecutive patients treated at our institution due to a severe fungal osteomyelitis after an arthroscopic ACL-R from November 2005 to March 2015. Patients were referred to our institution from different areas of our country. We evaluated the amount of bone resection required, type of final reconstructive procedure performed, and Musculoskeletal Tumor Society (MSTS) functional score. Results. A total of 21 consecutive patients were included in the study; 19 were male with median age of 28 years (IQR 25 to 32). All ACL-R were performed with hamstrings autografts with different fixation techniques. An oncological-type debridement was needed to control persistent infection symptoms. There were no recurrences of fungal infection after median of four surgical debridements (IQR 3 to 6). Five patients underwent an extensive curettage due to the presence of large cavitary lesions and were reconstructed with hemicylindrical intercalary allografts (HIAs), preserving the epiphysis. An open surgical debridement was performed resecting the affected epiphysis in 15 patients, with a median bone loss of 11 cm (IQR 11.5 to 15.6). From these 15 cases, eight patients were reconstructed with allograft prosthesis composites (APC); six with tumour-type prosthesis (TTP) and one required a femoral TTP in combination with a tibial APC. One underwent an above-the-knee amputation. The median MSTS functional score was 20 points at a median of seven years (IQR 5 to 9) of follow-up. Conclusion. This study suggests that mucormycosis infection after an ACL-R is a serious complication. Diagnosis is usually delayed until major bone destructive lesions are present. This may originate additional massive reconstructive surgeries with severe functional limitations for the patients. Level of evidence: IV. Cite this article: Bone Joint Open 2020;2(1):3–8

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Perthes’ disease (PD) is a childhood hip disorder that can affect the quality of life in adulthood due to femoral head deformity and osteoarthritis. There is very little data on how PD patients function as adults, especially from the patients’ perspective. The purpose of this study was to collect treatment history, demographic details, the University of California, Los Angeles activity score (UCLA), the 36-Item Short Form survey (SF-36) score, and the Hip disability and Osteoarthritis Outcome score (HOOS) of adults who had PD using a web-based survey method and to compare their outcomes to the outcomes from an age- and sex-matched normative population.

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Prior to the availability of vaccines, mortality for hip fracture patients with concomitant COVID-19 infection was three times higher than pre-pandemic rates. The primary aim of this study was to determine the 30-day mortality rate of hip fracture patients in the post-vaccine era.

Aims. Surgeons and most engineers believe that bone compaction improves implant primary stability without causing undue damage to the bone itself. In this study, we developed a murine distal femoral implant model and tested this dogma. Methods. Each mouse received two femoral implants, one placed into a site prepared by drilling and the other into the contralateral site prepared by drilling followed by stepwise condensation. Results. Condensation significantly increased peri-implant bone density but it also produced higher strains at the interface between the bone and implant, which led to significantly more bone microdamage. Despite increased peri-implant bone density, condensation did not improve implant primary stability as measured by an in vivo lateral stability test. Ultimately, the condensed bone underwent resorption, which delayed the onset of new bone formation around the implant. Conclusion. Collectively, these multiscale analyses demonstrate that condensation does not positively contribute to implant stability or to new peri-implant bone formation. Cite this article:Bone Joint Res. 2020;9(2):60–70

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Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).