Miquel Pons

Subtalar arthroereisis for posterior tibial tendon dysfunction: a preliminary report.

Background: The purpose of this study was to evaluate preliminary results with Kalix® subtalar arthroereisis in sinus tarsi for stage II posterior tibial tendon dysfunction. Methods: Twenty-one patients with stage II posterior tibial dysfunction, according to Johnson and Storm, underwent surgical treatment between July 1999 and December 2000. All patients were evaluated clinically using the America Orthopaedic Foot and Ankle Society (AOFAS) hindfoot-ankle score. We performed a tendon repair depending on the type and location of the injury and implanted a Kalix® endorthesis in the sinus tarsi. Results: Nineteen patients attended for clinical review with an average follow-up of 27.31 months (range, 19–36). AOFAS scale improved from a preoperative average of 47.2 to an average of 81.6 at revision. The most important improvement was observed in pain (16.3 preoperative to 31.6 postoperative). Two cases required removal of the endorthesis for pain, probably because the endorthesis was too big, without any loss of correction. Patient satisfaction was “satisfied” or “very satisfied” in 17/19. All except three patients would have elected to undergo the same procedure. Conclusions: Subtalar arthroereisis by means of implantation of a Kalix® endorthesis in the sinus tarsi, with prior correction of the deformity and tendon repair, offers an alternative to bone operations such as calcaneal osteotomies, lengthening the external column, or arthodesis in patients with stage II posterior tibial dysfunction.

Sodium hyaluronate in the treatment of hallux rigidus. A single-blind, randomized study

Background: The purpose of this study was to evaluate the effectiveness and safety of intra-articular sodium hyaluronate (Ostenil®mini) compared to intra-articular triamcinolone acetonide (Trigon depot®) in the treatment of painful hallux rigidus. Methods: Thirty-seven patients (ages 40 to 80 years) with painful early stage hallux rigidus were enrolled in the study. One group received an intra-articular injection with 1.0 ml sodium hyaluronate (SH); the other received an intra-articular injection of 1.0 ml triamcinolone acetonide (TA). Patients were evaluated on days 0, 14, 28, 56 and 84. Effectiveness was measured using the following parameters: joint pain at rest or on palpation (VAS), with passive motion, and gait pain; AOFAS hallux metatarsophalangeal score; use of analgesics and global assessment of the treatment by the patient and investigator. Safety was evaluated by the outcome of tolerance to treatment and observation of adverse events. Statistical analyses were performed using the Chi-square test, Mann-Whitney U test, Wilcoxon test and Friedman test. Results: Thirty-seven patients (40 feet) were evaluated. Pain at rest or with palpation and pain on passive mobilization decreased significantly in both treatment groups in comparison to baseline (p < 0.01), but no significant between-group differences were observed (p > 0.05). Gait pain improved substantially in the sodium hyaluronate group with significant differences compared to the triamcinolone group at days 28 and 56 (p < 0.05). The AOFAS total score improved significantly in the SH group compared to the TA group (p < 0.05). This was mainly due to improvements in the pain subscale. No between-group differences were seen regarding the use of analgesics. Global assessment of treatment by patients was good in both groups, and there was a significant between-group difference favoring SH when areas under the curves (AUC) were calculated (p < 0.05). Tolerance was good in both groups. Adverse events occurred in three patients. Conclusions: Intra-articular injections of sodium hyaluronate are effective and safe in decreasing hallux rigidus pain. The AOFAS scores in the SH group were significantly better than in the TA group.

Learning curve and short-term results with a short-stem CFP system

In conservative hip replacement it is important to remove only pathological tissue to preserve as much healthy bone as possible. The collum femoris preserving (CFP) system preserves the femoral neck and metaphyseal cancellous bone. We present our learning curve with this system and our preliminary results and conclusions. During 2001-2009 we placed 138 CFP prostheses in 90 men and 38 women (10 bilateral). The mean age of the patients was 57.1 years (range 22-76 years) and the mean follow-up 38.3 months. Seventy-three patients were active workers at the time of surgery. All patients began partial weight bearing at 24-36 hours and total weight bearing was allowed at 3 weeks postoperative. We have had 1 infection, 2 intraoperative partial shaft fractures that did not require treatment, 1 acetabular loosening, and 2 periprosthetic traumatic fractures treated by osteosynthesis in one case and femoral revision in the other. All but 3 active workers returned to work and 54.5% of the studied patients practice some sport or physical activity. The stem size was correct in 125 hips. Resorption at the prosthetic rim was found in 9 out of 134 hips. No clinical symptoms were found in these patients. There have been no stem revisions for aseptic loosening in the follow-up study. Although the current follow-up is too short to allow definitive conclusions, the CFP system has provided excellent short-term results.

Comparative effectiveness of ceramic-on-ceramic implants in stemmed hip replacement: A multinational study of six national and regional registries

BACKGROUND The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). METHODS A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. RESULTS A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term. CONCLUSIONS Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery.

Predicting the Burden of Revision Knee Arthroplasty: Simulation of a 20-Year Horizon

OBJECTIVES To estimate future utilization scenarios for knee arthroplasty (KA) revision in the Spanish National Health System in the short- and long-term and their impact on primary KA utilization. METHODS A discrete-event simulation model was built to represent KA utilization for 20 years (2012-2031) in the Spanish National Health System. Data on KA utilization from 1997 to 2011 were obtained from the minimum data set. Three scenarios of future utilization of primary KA (1, fixed number since 2011; 2, fixed age- and sex-adjusted rates since 2011; and 3, projection using a linear regression model) were combined with two prosthesis survival functions (W [worse survival], from a study including primary KA from 1995 to 2000; and B [better survival], from the Catalan Registry of Arthroplasty, including primary KA from 2005 to 2013). The simulation results were analyzed in the short-term (2015) and the long-term (2030). RESULTS Variations in the number of revisions depended on both the primary utilization rate and the survival function applied, ranging from increases of 8.3% to 31.6% in the short- term and from 38.3% to 176.9% in the long-term, corresponding to scenarios 1-B and 3-W, respectively. The prediction of increases in overall surgeries ranged from 0.1% to 22.3% in the short-term and from 3.7% to 98.2% in the long-term. CONCLUSIONS Projections of the burden of KA provide a quantitative basis for future policy decisions on the concentration of high-complexity procedures, the number of orthopedic surgeons required to perform these procedures, and the resources needed.

Results from the International Consortium of Orthopaedic Registries: An Innovative Distributed Research Network for Global Post-Market Surveillance: Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement: A Multinational Study of Six National and Regional Registries

BACKGROUND The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). METHODS A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. RESULTS A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term. CONCLUSIONS Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery.

Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement

BACKGROUND The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). METHODS A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. RESULTS A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term. CONCLUSIONS Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery.