Electrochemically applied hydroxyapatite on the cementless porous surface of Bi-Metric stems reduces early migration and has a lasting effect : an efficacy trial of a randomized five-year follow-up radiostereometric study.

AIMS: BoneMaster is a thin electrochemically applied hydroxyapatite (HA) coating for orthopaedic implants that is quickly resorbed during osseointegration. Early stabilization is a surrogacy marker of good survival of femoral stems. The hypothesis of this study was that a BoneMaster coating yields a fast early and lasting fixation of stems. METHODS: A total of 53 patients were randomized to be treated using Bi-Metric cementless femoral stems with either only a porous titanium plasma-sprayed coating (P group) or a porous titanium plasma-sprayed coating with an additional BoneMaster coating (PBM group). The patients were examined with radiostereometry until five years after surgery. RESULTS: At three months, the mean total translation (TT) was 0.95 mm (95% confidence interval (CI) 0.68 to 1.22) in the P group and 0.57 mm (95% CI 0.31 to 0.83) in the PBM group (p = 0.047). From two to five years, the TT increased by a mean of 0.14 mm (95% CI 0.03 to 0.25) more in the P group than in the PBM group (p = 0.021). In osteopenic patients (n = 20), the mean TT after three months was 1.61 mm (95% CI 1.03 to 2.20) in the P group and 0.73 mm (95% CI 0.25 to 1.21) in the PBM group (p = 0.023). After 60 months, the mean TT in osteopenic patients was 1.87 mm (95% CI 1.24 to 2.50) in the P group and 0.82 mm (95% CI 0.30 to 1.33) in the PBM group (p = 0.011). CONCLUSION: There was less early and midterm migration of cementless stems with BoneMaster coating compared with those with only a porous titanium plasma-sprayed coating. Although a BoneMaster coating seems to be important for stem fixation, especially in osteopenic patients, further research is warranted. Cite this article: Bone Joint J 2022;104-B(6):647-656.

Cementless femoral stems with lower canal fill ratio have similar mid-term to long-term outcomes to those with adequate fill ratio in Dorr type C femurs.

BACKGROUND: Lower canal fill ratio was reported to correlate with aseptic loosening in many studies. However, the most widely used standard of fill ratio seemed inapplicable to Dorr type C femurs. We aimed to adapt the method of measuring the fill ratio in Dorr type C femurs and compare the outcomes among patients with different fill ratios. METHODS: Twenty patients with Corail stems implanted in their Dorr type C femurs received spectrum CT to evaluate the whole-stem's fill ratio. Pearson Correlation Coefficient was calculated to assess the correlation between the fill ratio in X-ray film and spectrum CT. Then 87 THAs were involved in this study, divided into the fill ratio ≤ 80% group and the fill ratio > 80% group. Clinical and radiological outcomes were evaluated with a mean follow-up of 8.2 years. RESULTS: Fill ratio at 2 cm below the lesser trochanter in anterior-posterior X-ray film correlated with the whole-stem's fill ratio (r = 0.50, P = 0.02). Survival rate of stem, function scores, and radiological outcomes between the two groups showed no significant difference. In the fill ratio > 80% group, intraoperative fracture was significantly higher (19% VS 5%, P < 0.05). CONCLUSION: Patients with lower fill ratios at 2 cm below the lesser trochanter did not have poorer functional scores or more subsidence, but had a lower intraoperative fracture rate. The revision rates of the two groups presented no significant difference, but this result need to be confirmed in larger cohort in the future. In Dorr type C femurs, risk of fracture and the special morphology of the femur should be noted, and high fill ratio is not the most decisive factor for stem size selecting.

Ten-year comparison of two different techniques for femoral bone cavity preparation-broaching versus compaction in patients with cementless total hip arthroplasty : a randomized radiostereometric study of 30 total hip arthroplasties in 15 patients operated bilaterally.

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.

Revision hip arthroplasty with a modular cementless stem: mid-term follow up.

Despite the increasing volume of revision total hip arthroplasty (THA) being performed in the United States, there are few studies reporting mid-term clinical and radiographic outcomes of modular fully porous-coated femoral stems. We retrospectively studied a consecutive series of patients who underwent revision THA with a modular extensively porous-coated femoral component at a single institution and by a single surgeon. The final study group included 54 hips (52 patients) followed for an average of 84 months. Ten-year survival rates with revision for any reason and revision for femoral loosening as endpoints were 94% and 100%, respectively. No complications regarding the modular junction were encountered. Of the 50 hips with adequate radiographs, all showed proximal ingrowth and 42 (84%) had both proximal and distal ingrowth. The modular, fully porous-coated femoral stem studied demonstrated excellent survivorship and bone ingrowth at mid-term follow up.

Revision Hip Arthroplasty with a Cementless Femoral Stem / 대한고관절학회지

PURPOSE: To evaluate the clinical and radiographic results of patients who received revision total hip arthroplasty using cementless femoral stems. MATERIALS AND METHODS: This study included 26 patients who underwent revision total hip arthroplasty using a cementless femoral stems in our hospital, between Jan 2000 and May 2010, and were able to be evaluated in the final follow-up. The mean age was 63.8 years at the time of the revision surgery, and the follow up period was an average of 45 months. The causes of revision were aseptic loosening in 11 cases, periprosthetic fracture in 6 cases, femoral osteolysis in 6 cases, and infection in 3 cases. The radiologic results were evaluated in term of subsidence, loosening, and the stress shielding. The clinical results were evaluated by the Harris hip score and thigh pain. RESULTS: Harris hip score improved from 41.2 points preoperatively to 85.8 points at the final follow-up. There were 5 cases that complained of thigh pain at the last follow-up. Subsidence of femoral stem of more than 10 mm was observed in 3 cases. Stress shielding was noticed in 6 hips. The 3 grafted strut allografts were completely fused with the host bone. Complications included 2 cases of intraoperative periprosthetic fracture and 3 cases of dislocation. CONCLUSION: We obtained favorable clinical and radiologic outcomes in revision total hip arthroplasty using a cementless femoral stems. However, thigh pain and stress shielding resulted from the diameter of femoral stem being too large.