Larger 5-year migration but similar polyethylene wear of cementless hemispherical cups with electrochemically applied hydroxyapatite (BoneMaster) coating compared with porous plasma-spray titanium: a randomized 5-year RSA study.

BACKGROUND AND PURPOSE: BoneMaster (BM) is a thin electrochemically applied hydroxyapatite (HA) implant coating marketed with expectations of improved osseointegration properties but less polyethylene (PE) wear. We compared the midterm cup migration and PE wear of cementless porous-coated hemispherical cups with and without BM. PATIENTS AND METHODS: In this patient-blinded, randomized controlled trial, 53 patients with a mean age of 64 years (55-75) received total hip arthroplasty with a porous-coated (P) or porous and BoneMaster (PBM) coated Exceed cup and ArCom E1 infused PE. Patients were followed with RSA, Hip Osteoarthritis Outcome Score (HOOS), and Euro-Qol-5-3L (EQ-5D) at 3 and 6 months, and 1-, 2-, and 5-year follow-up. RESULTS: At 5-year follow-up, total translation and maximum total point motion was 0.28 mm (95% CI 0.08; 0.47) and 0.52 mm (CI 0.12; 0.93) higher in the PBM group than in the P group. PE wear was comparable between PBM and P cups, and 2D wear rate from 1-year follow-up to last follow-up was 0.03 mm (CI 0.02-0.03). The 5-year anterior translation was 0.05 mm (CI -0.10 to 0.21) in the normal BMD group and 0.40 mm (CI 0.22-0.57) in the osteopenia group. INTERPRETATION: At 5-year follow-up, Exceed cups in the PBM group migrated more than in the P group but the PE wear rate was low and similar. This study does not indicate any advantage of additional BoneMaster coating compared with porous coating alone on cementless hemispherical cups with regards to migration, polyethylene wear, and clinical outcomes.

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.

The wound healing effect of local leukocyte platelet-rich plasma after total hip arthroplasty: A randomized controlled trial.

Rapid wound closure is important after arthroplasty procedures to prevent postoperative complications. Platelets are rich in growth factors and leukocytes contribute to innate immunity. We hypothesized that topical leukocyte platelet-rich plasma (L-PRP) derived from the blood of patients would be beneficial to wound healing. In this randomized controlled trial, patients subjected to elective total hip arthroplasty (THA) were assigned by concealed allocation either L-PRP application onto the sutured fascia or no application (control) after the THA intervention. In addition, all patients received 1.5 g protein/kg, 5 g L-arginine, 500 mg vitamin C and 44 mg zinc daily over the 4-week postoperative period to obtain optimal nutrition. The primary endpoint was complete healing of the skin incision. The secondary endpoints were blood transfusions, length of hospital stay, pain and wound infections. Sixteen patients in the L-PRP group and 17 patients in the control group completed the trial. L-PRP treatment accelerated complete wound healing after 3 weeks (seven in the L-PRP group vs. zero in the control group, p = 0.003) and after 4 weeks (12 in the L-PRP group vs. six in the control group, p = 0.037). No postoperative superficial wound infections occurred within 4 weeks, and there were no significant differences in the other secondary outcomes. L-PRP generated in 10 sex-matched healthy volunteers revealed increased concentrations of platelets (5.8-fold) and leukocytes (2.3-fold) compared with those in whole blood. Furthermore, the concentration of keratinocyte mitogen epidermal growth factor in L-PRP (380 ± 130 pg/ml, mean ± SD) was higher (p < 0.001) than that in serum (130 ± 26 pg/ml). In conclusion, a single intraoperative local application of L-PRP promoted wound healing after THA, possibly mediated by EGF receptor agonists.

Factors Associated with Increased Risk of Recurrence following Treatment of Trigger Finger with Corticosteroid Injection.

Introduction The aim of the study was to estimate recurrence rates, time to recurrence, and predisposing factors for recurrence of trigger finger when treated with corticosteroid (CS) injection as primary treatment. Materials and Methods In a retrospective chart review, we identified primary trigger fingers treated with CS injection as primary treatment. Affected hand and finger, recurrence, time to recurrence, duration of symptoms, secondary treatment type, and comorbidities were recorded. A total of 539 patients were included with a mean follow-up of 47.6 months Results In total, 330/539 (61%) recurrences were registered. Mean time to recurrence was 312 days. Increased risk of recurrence was seen after treatment of the third finger (relative risk [RR]: 1.22; 95% confidence interval [CI]: 1.06-1.39). Several comorbidities were associated with increased risk of recurrence: carpal tunnel syndrome (RR: 1.27; 95% CI: 1.07-1.52), thyroid disease (RR: 1.45; 95% CI: 1.15-1.83), or shoulder diseases (RR: 1.58; 95% CI: 1.36-1.83). Conclusion We found a recurrence rate after primary treatment of CS injection for trigger finger of 61%. Most recurrences happened within 2 years and we found treatment of third finger, carpal tunnel syndrome, shoulder, or thyroid disease to be associated with an increased risk of recurrence of symptoms.

Unexpected positive cultures after revision shoulder arthroplasty: does it affect outcome?

BACKGROUND: Several studies have confirmed a high rate of unexpected positive cultures (UPCs) after presumably aseptic revisions of shoulder arthroplasties; however, the impact on the outcome is still unclear. The purpose of this prospective study is to compare the patient-reported outcomes of standard revisions with and without the emergence of UPCs. METHODS: During a 3-year period, we included all patients who were revised for reasons other than suspicion of infection from 2 orthopedic centers. Five biopsies were obtained from every revision, and only cultures with the same bacteria in at least 3 biopsy specimens were classified as UPCs. All patients were assessed using the Oxford Shoulder Score (OSS) and range of motion preoperatively and after at least a 2-year follow-up. RESULTS: In this study, 124 patients were included, with a median follow-up of 29 months (range 29-32), and UPCs emerged after 27 revisions (22%), with Cutibacterium acnes accounting for 67% (18/27). At baseline, the OSS was 22 in both the culture-negative and UPC groups (P = .46). Then, at follow-up, the OSS was 37 in the culture-negative group and 35 in the UPC group (P = .91). The forward elevation increased significantly by 44° and 41°, respectively, in the 2 groups, but no statistically significant difference between the culture-negative group and the UPC group was found (P = .66). In contrast, the external rotation was unchanged after the revision, and again, no difference in the change between the culture-negative and UPC groups (P = .54) was observed. Subgroup analyses stratified by different implant designs revealed equal patterns with no statistical differences in outcome. CONCLUSION: We did not find a difference in outcome after a presumed aseptic revision regardless of the emergence of UPCs. Similarly, we could not demonstrate that patients with UPCs presented with poorer function at baseline compared with culture-negative patients. The clinical relevance of UPCs thus requires further evaluation, especially in the case of C acnes as a potential pathogenic versus a merely colonizing microbe.

Patient-reported outcomes following interposition arthroplasty of the basal joint of the thumb.

LEVEL OF EVIDENCE: II - prospective cohort.

Higher early proximal migration of hemispherical cups with electrochemically applied hydroxyapatite (BoneMaster) on a porous surface compared with porous surface alone: a randomized RSA study with 53 patients.

Background and purpose - BoneMaster (BM) is an electrochemically deposited hydroxyapatite (HA) implant-coating, which is evenly distributed, thin, and quickly resorbed. It is designed to stimulate osseointegration and early implant stability and alleviate longer-term HA-induced third-body polyethylene wear. This study evaluates early cup migration and functional outcomes of cementless porous-coated hemispherical cups with or without BM.Patients and methods - In a patient-blinded, randomized, controlled trial 53 patients at mean 64 years (55-75) with coxarthritis were operated with an Exceed cup (Zimmer Biomet) and Bi-Metric stem (Zimmer Biomet) with porous and BM coating (PBM) or with porous coating alone (P). Follow-ups were performed postoperatively and at 3, 6, 12, and 24 months. Effect measures were cup migration measured with RSA and PROMs.Results - At 6-month follow-up, proximal cup migration in the PBM group (0.09 mm, 95% CI 0.02-0.20) was higher than in the P group (0.25 mm, CI 0.15-0.35). At 1- and 2-year follow-up, cup migration in all 6 degrees of freedom was similar between groups (p > 0.2). From before surgery to 2-year follow-up, Oxford Hip Score (OHS) increased by 17 points (CI 14-20). Hip disability and Osteoarthritis Outcome Score (HOOS) increased in all sub-scores, but was more pronounced for PBM cups compared with P cups in the Symptoms sub-score (p = 0.04).Interpretation - Contrary to expectations, PBM cups had higher early migration than P cups. At 2-year follow-up, migration was similar between groups. There seems to be no early benefit of BM coating on acetabular cups.

Labeled white blood cell/bone marrow single-photon emission computed tomography with computed tomography fails in diagnosing chronic periprosthetic shoulder joint infection.

BACKGROUND: Shoulder periprosthetic joint infections (PJI) caused by low-virulent bacteria pose a diagnostic challenge. Combined labeled leukocyte (WBC) and technetium 99m sulfur colloid bone marrow imaging (WBC/BM) is considered the radionuclide imaging gold standard for diagnosing lower limb PJI. However, it is laborious and expensive to perform, and documentation on shoulder arthroplasties is lacking. This study investigated WBC/BM single-photon emission computed tomography-computed tomography diagnostic performance in shoulder PJI. METHOD: All patients with a failed arthroplasty referred to a highly specialized shoulder department were scheduled for a diagnostic program including a WBC/BM. If an arthroplasty was revised, biopsy specimens were obtained and cultured for 14 days. The diagnostic performance of WBC/BM imaging was determined using biopsy specimens as a reference. RESULTS: Of the 49 patients who underwent a WBC/BM scan, 29 (59%) were revised. Infection was present in 11 patients, in whom 2 WBC/BM scans were true positive. The WBC/BM scan in 9 patients was false negative. The remaining 18 patients all had a true negative WBC/BM scan. WBC/BM showed a sensitivity 0.18 (95% confidence interval [CI], 0.00-0.41) and specificity 1.00 (95% CI, 1.00-1.00) in detecting shoulder PJI. The positive predictive value was 1.00 (95% CI, 1.00-1.00), and negative predictive value was 0.67 (95% CI, 0.49-0.84). No patients infected with Cutibacterium (formerly Propionibacterium) acnes resulted in a positive WBC/BM, nor had they preoperative or perioperative signs of infection. CONCLUSION: A positive WBC/BM was found only in patients with obvious PJI. Hence, the scan added nothing to the preoperative diagnosis. The WBC/BM single-photon emission computed tomography-computed tomography scan cannot be recommended as a screening procedure when evaluating failed shoulder arthroplasties for possible infection.

A Randomized Seven-Year Study on Performance of the Stemmed Metal M2a-Magnum and Ceramic C2a-Taper, and the Resurfacing ReCap Hip Implants.

BACKGROUND: The large-diameter metal-on-metal hip prostheses were expected to have low wear and reduced dislocation rate compared to the traditional metal-on-polyethylene implants. We compare 2 such prostheses, the ReCap resurfacing implant and the M2a-Magnum stemmed implant, with the C2a ceramic-on-ceramic stemmed implant as to clinical performance, serum concentrations of prosthesis metals, and the durability of the implants in a randomized, controlled clinical trial at 7 years of follow-up. METHODS: All included patients had osteoarthritis. Preoperatively, the size of the implants was estimated from a magnetic resonance imaging (MRI) scan. Follow-up data included serum cobalt and chromium concentrations, Oxford and Harris Hip Scores, leg press and abduction force, 6-minute walk distance, WOMAC and SF-36 self-assessment scores, and from the 7th postoperative year also ultrasonography (US) examination of the soft tissue adjacent to the implant as well as MRI with metal artifact reduction sequence (MARS-MRI) when indicated. RESULTS: One hundred fifty-two hips in 146 patients were included. The serum cobalt and chromium concentrations were significantly higher for the 2 metal-on-metal prostheses than for the ceramic-on-ceramic, with the M2a-Magnum as the highest. No significant difference was found between the groups concerning physical performance measurements and scores as well as dislocations and prosthesis survival. Five revisions were done and concerned all groups, for reasons of pain, high serum cobalt and chromium concentrations, cystic fluid collection around the joint, and infection. Metal concentrations, US, and MARS-MRI contributed to the decision making regarding prosthesis revision. CONCLUSION: Metal concentrations were significantly higher for the metal-on-metal prostheses than for the ceramic-on-ceramic. The clinical performance was good in all 3 prosthesis groups. Metal concentrations, US, and MARS-MRI findings were of use to identify hips needing revision. ID Number in ClinicalTrials.gov PRS: NCT00284674.

A randomised, controlled clinical study on total hip arthroplasty using 4 different bearings: results after 10 years.

PURPOSE: To compare 4 different bearings in total hip arthroplasty (THA) in a randomised controlled clinical study on clinical performance. METHODS: 393 patients with osteoarthritis of the hip or avascular necrosis were included and allocated to 1 of the head-and-cup couples zirconia-on-polyethylene (group A), metal-on-metal (group B), zirconia-on-polyethylene with the liner moulded into the shell (group C), or alumina-on-alumina (group D). In the individual case the surgeon could choose other implants if indicated. RESULTS: 299 patients were operated with the allocated prosthesis. The estimated cumulated prosthesis survival percentages and 95% confidence interval after 10 years were: group A 84.6 (75.8-93.4); group B 95.0 (89.5-100); group C 93.2 (86.7-99.7); group D 66.1 (54.5-77.7). The patients' physical function was significantly improved and remained equally good in all 4 groups, however slightly declining with ageing. The luxation rate was initially high, and equal between the groups, but was reduced by improving the surgical procedure introducing capsule repair by reinsertion of the short external hip rotators. CONCLUSIONS: The metal-on-metal or zirconia-on-polyethylene prostheses had high 10-year survival percentages. The longevity of these bearing couples by themselves was not related to the combination of materials. The zirconia-on-polyethylene prosthesis with the liner mounted peroperatively possibly exhibited cases of backside wear which the corresponding bearing couple with moulded polyethylene (Asian) did not. The alumina-on-alumina bearing performed poorly - it was redesigned after our study initiation and later withdrawn from the market.

Local infiltration analgesia is not improved by postoperative intra-articular bolus injections for pain after total hip arthroplasty.

BACKGROUND AND PURPOSE: The effect of postoperative intra-articular bolus injections after total hip arthroplasty (THA) remains unclear. We tested the hypothesis that intra-articular bolus injections administered every 6 hours after surgery during the first 24 hours would significantly improve analgesia after THA. PATIENTS AND METHODS: 80 patients undergoing THA received high-volume local infiltration analgesia (LIA; 200 mg ropivacaine and 30 mg ketorolac) followed by 4 intra-articular injections with either ropivacaine (100 mg) and ketorolac (15 mg) (the treatment group) or saline (the control group). The intra-articular injections were combined with 4 intravenous injections of either saline (treatment group) or 15 mg ketorolac (control group). All patients received morphine as patient-controlled analgesia (PCA). The primary outcome was consumption of intravenous morphine PCA and secondary outcomes were consumption of oral morphine, pain intensity, side effects, readiness for hospital discharge, length of hospital stay, and postoperative consumption of analgesics at 3, 6, and 12 weeks after surgery. RESULTS: There were no statistically significant differences between the 2 groups regarding postoperative consumption of intravenous morphine PCA. Postoperative pain scores during walking were higher in the treatment group from 24-72 hours after surgery, but other pain scores were similar between groups. Time to readiness for hospital discharge was longer in the treatment group. Other secondary outcomes were similar between groups. INTERPRETATION: Postoperative intra-articular bolus injections of ropivacaine and ketorolac cannot be recommended as analgesic method after THA.

Systemic intermittent parathyroid hormone treatment improves osseointegration of press-fit inserted implants in cancellous bone.

BACKGROUND AND PURPOSE: Intermittent administration of parathyroid hormone (PTH) has an anabolic effect on bone, as confirmed in human osteoporosis studies, distraction osteogenesis, and fracture healing. PTH in rat models leads to improved fixation of implants in low-density bone or screw insertion transcortically. MATERIAL AND METHODS: We examined the effect of human PTH (1-34) on the cancellous osseointegration of unloaded implants inserted press-fit in intact bone of higher animal species. 20 dogs were randomized to treatment with human PTH (1-34), 5 µg/kg/day subcutaneously, or placebo for 4 weeks starting on the day after insertion of a cylindrical porous coated plasma-sprayed titanium alloy implant in the proximal metaphyseal cancellous bone of tibia. Osseointegration was evaluated by histomorphometry and fixation by push-out test to failure. RESULTS: Surface fraction of woven bone at the implant interface was statistically significantly higher in the PTH group by 1.4 fold with (median (interquartile range) 15% (13-18)) in the PTH group and 11% (7-13) in control. The fraction of lamellar bone was unaltered. No significant difference in bone or fibrous tissue was observed in the circumferential regions of 0-500, 500-1,000, and 1,000-2,000 µm around the implant. Mechanically, the implants treated with PTH showed no significant differences in total energy absorption, maximum shear stiffness, or maximum shear strength. INTERPRETATION: Intermittent treatment with PTH (1-34) improved histological osseointegration of a prosthesis inserted press-fit at surgery in cancellous bone, with no additional improvement of the initial mechanical fixation at this time point.

The influence of parathyroid hormone treatment on implant fixation.

INTRODUCTION: Primary joint replacements generally function well with excellent clinical results. However, failure rates for young patients are still high and increasing in number. The longterm survival of an uncemented prosthesis is influenced by multiple factors depending on host physiology as well as properties of implanted material, initial mechanical stability, early osseointegration, and the surrounding bone. Parathyroid hormone is the principal regulator of calcium homeostasis and involved in the control of bone remodelling. Parathyroid hormone administered intermittently increases bone formation and mass by osteoblast stimulation. Early osseointegration and implant fixation could potentially be enhanced with adjuvant parathyroid hormone treatment. The aim of the studies in this PhD thesis was to determine if implant fixation of experimental implants can be improved with adjuvant intermittent administration of parathyroid hormone. STUDIES: All studies used an experimental canine model of early implant fixation inserting porous coated titanium alloy implants with no weight bearing in a bed of cancellous bone. The study design was un-paired. Test animals were randomised to PTH (1-34) 5 µm/kg daily for 4 weeks. Implant fixation was defined by mechanical stability and osseointegration. Study I investigated the effect of parathyroid hormone on implant fixation of implants inserted press fit with surrounding bone in the proximal tibia of 20 canines. Histomorphometric analysis showed increased amount of new bone in contact with the implant. No improvement was observed in the surrounding bone. PTH did not increase mechanical fixation in pushout test. Study II investigated the effect of parathyroid hormone on implant fixation of implants surrounded by a critical 1 mm gap. Implants where inserted in the tibia of 20 canines. Bone density was increased in the inner gap and outer gap with PTH treatment. Bone at implant interface improved with PTH but did not achieve significance. Push-out testing showed that PTH Increased mechanical implant fixation in shear stiffness and total energy absorption. Shear strength was not significantly increased. Study III investigated the effect on implant fixation of implants surrounded by a 2.5 mm gap in which morsellised allograft was impacted. Implants were inserted in 20 Canines in the humerus. Histomorphometric analysis showed that PTH increased the amount of new bone within the gap, but not in contact the implant. There were no differences in amount of allograft. The push-out testing showed no differences in mechanical parameters. CONCLUSION: The studies in this PhD thesis demonstrated that parathyroid hormone increases bone healing around implants in situations of insertion in press-fit or in more challenging environments of empty and grafted gaps. Early fixation was increased in implants with gaps, in which pure gap bone stimulation improved fixation. This warrants further preclinical studies.

Parathyroid hormone treatment increases fixation of orthopedic implants with gap healing: a biomechanical and histomorphometric canine study of porous coated titanium alloy implants in cancellous bone.

Parathyroid hormone (PTH) administered intermittently is a bone-building peptide. In joint replacements, implants are unavoidably surrounded by gaps despite meticulous surgical technique and osseointegration is challenging. We examined the effect of human PTH(1-34) on implant fixation in an experimental gap model. We inserted cylindrical (10 × 6 mm) porous coated titanium alloy implants in a concentric 1-mm gap in normal cancellous bone of proximal tibia in 20 canines. Animals were randomized to treatment with PTH(1-34) 5 µg/kg daily. After 4 weeks, fixation was evaluated by histomorphometry and push-out test. Bone volume was increased significantly in the gap. In the outer gap (500 µm), the bone volume fraction median (interquartile range) was 27% (20-37%) for PTH and 10% (6-14%) for control. In the inner gap, the bone volume fraction was 33% (26-36%) for PTH and 13% (11-18%) for control. At the implant interface, the bone fraction improved with 16% (11-20%) for PTH and 10% (7-12%) (P = 0.07) for control. Mechanical implant fixation was improved for implants exposed to PTH. For PTH, median (interquartile range) shear stiffness was significantly higher (PTH 17.4 [12.7-39.7] MPa/mm and control 8.8 [3.3-12.4] MPa/mm) (P < 0.05). Energy absorption was significantly enhanced for PTH (PTH 781 [595-1,198.5] J/m(2) and control 470 [189-596] J/m(2)). Increased shear strength was observed but was not significant (PTH 3.0 [2.6-4.9] and control 2.0 [0.9-3.0] MPa) (P = 0.08). Results show that PTH has a positive effect on implant fixation in regions where gaps exist in the surrounding bone. With further studies, PTH may potentially be used clinically to enhance tissue integration in these challenging environments.

The effect on bone growth enhancement of implant coatings with hydroxyapatite and collagen deposited electrochemically and by plasma spray.

Skeletal bone consists of hydroxyapatite (HA) [Ca(10)(PO(4))(6)(OH)(2)] and collagen type I, both of which are osseoconductive. The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable long-lasting fixation between bone and an implant surface. In this study, we evaluated the mechanical fixation and tissue distribution surrounding implants coated with three surfaces: plasma-sprayed HA coating, thinner coating of electrochemical-assisted deposition of HA, and an identical thin coating with a top layer of mineralized collagen. Uncoated plasma-sprayed titanium (Ti-6Al-4V) served as negative control. The electrochemical-assisted deposition was performed near physiological conditions. We used a canine experimental joint replacement model with four cylindrical implants (one of each treatment group) inserted in the humeri cancellous metaphyseal bone in a 1 mm gap. Observation time was 4 weeks. The mechanical fixation was quantified by push-out test to failure, and the peri-implant tissue formation by histomorphometric evaluation. HA coatings deposited by plasma spray technique or electrochemically, increased the mechanical fixation and bone ongrowth, but there was no statistical difference between the individual HA applications. Addition of collagen to the mineralized phase of the coating to create a more bone natural surface did not improve the osseoconductive effect of HA.

Radiation exposure to the orthopaedic surgeon during periacetabular osteotomy.

The objective of this study was to directly measure the radiation exposure to the orthopaedic surgeon and to measure dose points to the surgeon's fingers, thyroid gland, and forehead during intraoperative fluoroscopy in periacetabular osteotomy (PAO). In a series of 23 consecutive periacetabular osteotomy procedures, exposure monitoring was carried out using thermo luminescent dosimeters. The effective dose received by the operating surgeon was 0.008 mSv per operation which adds up to a yearly dose of 0.64 mSv from PAO. The median point equivalent dose (mSv) exposure under PAO was 0.009 for the forehead and thyroid gland, 0.045 for the right index finger, and 0.039 for the left index finger. The effective estimated yearly dose received by the operating surgeon was very low. Wearing a lead collar reduces radiation exposure to the thyroid gland while the lead gloves did not protect the surgeon's fingers.

Bone growth enhancement in vivo on press-fit titanium alloy implants with acid etched microtexture.

Early bone ongrowth secures long-term fixation of primary implants inserted without cement. Implant surfaces roughened with a texture on the micrometer scale are known to be osseoconductive. The aim of this study was to evaluate the bone formation at the surface of acid etched implants modified on the micro-scale. We compared implants with a nonparticulate texture made by chemical milling (hydrofluoric acid, nitric acid) (control) with implants that had a dual acid etched (hydrofluoric acid, hydrochloric acid) microtexture surface superimposed on the primary chemically milled texture. We used an experimental joint replacement model with cylindrical titanium implants (Ti-6Al-4V) inserted paired and press-fit in cancellous tibia metaphyseal bone of eight canines for 4 weeks and evaluated by histomorphometric quantification. A significant twofold median increase was seen for bone ongrowth on the acid etched surface [median, 36.1% (interquartile range, 24.3-44.6%)] compared to the control [18.4% (15.6-20.4%)]. The percentage of fibrous tissue at the implant surface and adjacent bone was significantly less for dual acid textured implants compared with control implants. These results show that secondary roughening of titanium alloy implant surface by dual acid etching increases bone formation at the implant bone interface.