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Background and purpose: The primary aim of this systematic review and meta-analysis was to evaluate the success rate of 3 different epiphysiodesis techniques with implant usage for the treatment of leg-length discrepancy (LLD) in the pediatric population. The secondary aim was to address effectiveness (final LLD) and the reported complications of staples, tension-band plates (TBP), and percutaneous epiphysiodesis screws (PETS). Methods: In this systematic review we searched MEDLINE (PubMed), Embase, Cochrane Library, Web of Science and Scopus for studies on skeletally immature patients with LLD treated with epiphysiodesis with an implant. The extracted outcome categories were effectiveness of epiphysiodesis (LLD measurements pre-/postoperatively, successful/unsuccessful) and complications that were graded on severity. Results: 44 studies (2,184 patients) were included. 455 underwent epiphysiodesis with PETS, 578 patients with TBP, and 1,048 with staples. Successful epiphysiodesis was reported in 76% (95% confidence interval [CI] 61–89) with PETS (9 studies), 67% (CI 54–79) with TBP (10 studies), and 51% (CI 28–65) with Blount staples (8 studies). From pooled analysis, the severe complications rate was 7% for PETS, 17% for TBP, and 16% for Blount staples. Angular deformity was reported in 4% after PETS, 10% after TBP, and 17% after Blount staples. Conclusion: Our results showed that epiphysiodesis with PETS implants was the most successful technique. PETS had a higher success rate, fewer severe complications, and a lower proportion with angular deformity.

Aims: Femoral bone preparation using compaction technique has been shown to preserve bone and improve implant fixation in animal models. No long-term clinical outcomes are available. There are no significant long-term differences between compaction and broaching techniques for primary total hip arthroplasty (THA) in terms of migration, clinical, and radiological outcomes. Methods: A total of 28 patients received one-stage bilateral primary THA with cementless femoral stems (56 hips). They were randomized to compaction on one femur and broaching on the contralateral femur. Overall, 13 patients were lost to the ten-year follow-up leaving 30 hips to be evaluated in terms of stem migration (using radiostereometry), radiological changes, Harris Hip Score, Oxford Hip Score, and complications. Results: Over a mean follow-up period of 10.6 years, the mean stem subsidence was similar between groups, with a mean of -1.20 mm (95% confidence interval (CI) -2.28 to -0.12) in the broaching group and a mean of -0.73 mm (95% CI -1.65 to 0.20) in the compaction group (p = 0.07). The long-term migration patterns of all stems were similar. The clinical and radiological outcomes were similar between groups. There were two intraoperative fractures in the compaction group that were fixed with cable wire and healed without complications. No stems were revised. Conclusion: Similar stem subsidence and radiological and clinical outcomes were identified after the use of compaction and broaching techniques of the femur at long-term follow-up. Only the compaction group had intraoperative periprosthetic femur fractures, but there were no long-term consequences of these. Cite this article: Bone Jt Open 2021;2(12):1035–1042.

(1) Background: Metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) was presumed to provide superior functional outcomes compared to metal-on-polyethylene (MoP) THA. (2) Methods: We compared muscle mass, power, step test asymmetry, and patient-reported outcomes between MoM THA/HRA and MoP THA. A total of 51 MoM THA/HRAs and 23 MoP THAs participated in the cross-sectional study at a mean of 6.5 (2.4–12.5) years postoperatively. Muscle mass was measured by Dual energy X-ray Absorption (DXA) scans and muscle power in a Leg Extensor Power Rig. Step test asymmetry was obtained with an Inertial Measurement Unit (IMU). The patients completed the Harris Hip Score (HHS) and the Copenhagen Hip and Groin Outcome Score (HAGOS). (3) Results: The MoM THA/HRA group had a greater inter-limb difference in hip muscle mass compared to the MoP THA group (p = 0.02). Other inter-limb differences in muscle mass and power were similar (p > 0.05). Muscle mass of the thigh and calf area and muscle power in both legs were higher in MoM THA/HRA compared to MoP THA (p < 0.009). Step test time asymmetry when ascending was lower in MoM THA/HRA compared to MoP THA (p = 0.03). HHS and HAGOS scores were similar between groups (p > 0.05). (4) Conclusion: Overall, we could not verify the hypothesis that MoM THA/HRA contributes to superior functional outcomes compared to MoP THA.

Purpose: Young and physically active patients have mainly received metal-on-metal (MoM) total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA). However, the correlation between daily physical activity (PA) levels, serum-ion concentrations of chromium and cobalt and pseudotumours formation of patients who underwent MoM THA/RHA is insufficiently explored. Methods: Ninety-nine patients with 134 hip articulations, 71 MoM THA/RHA and 63 MoP THA participated in a cross-sectional study at XXX University Hospital, Denmark, at mean 7.3 (range: 0.4–21.7) years after surgery. Patients' daily PA was monitored during a two-week period using a triaxial accelerometer. Metal artefact reduction sequence magnetic resonance imaging scans, estimation of serum-ion concentrations of chromium and cobalt and the Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire were completed on Day 14. Results: Patients with a pseudotumour who underwent MoM THA/RHA had a higher average cadence of median 101.4 [interquartile range (IQR: 95.5–105)] steps/min than patients without a pseudotumor, median 96.7 (IQR: 92.2–103) steps/min (p = 0.02). Serum-ion concentrations of chromium and cobalt were higher in patients with a pseudotumour who underwent MoM THA/RHA, median 2.57 (IQR: 1.4–3.4) μg/L and 1.80 (IQR: 1.2–2.6) μg/L, respectively, than in patients without a pseudotumour, median 1.85 (IQR: 1.1–3.2) μg/L and 1.34 (IQR: 0.9–2.2) μg/L in MoM THA/RHA (p = 0.04 and p = 0.03). There was no statistical difference in these parameters between patients with and without a pseudotumour who underwent MoP THA. Daily PA levels of patients who underwent MoM THA/RHA were significantly correlated with serum-ion concentrations of chromium (p = 0.0002, r = 0.44) and cobalt (p = 0.005, r = 0.34), whereas no correlations were seen among patients who underwent MoP THA (p > 0.12). Conclusion: The daily PA level of patients who underwent MoM THA/RHA influences the serum-ion concentrations of chromium and cobalt and the risk of pseudotumour formation. Translational potential of this article: Results of this article add important knowledge on potential recommendations of prosthesis selection for patients with a high level of physical activity. Keywords: 3D accelerometer, Clinical outcome measures, Metal-on-metal, Magnetic resonance imaging, Metal-ion concentrations, Resurfacing hip arthroplasty, Total hip arthroplasty