Patients successfully lose body weight after primary total knee arthroplasty but not more than a matched general population.

INTRODUCTION: High BMI is associated with increased risk for knee osteoarthritis, ultimately necessitating total knee arthroplasty (TKA). The aim of this retrospective study was to (1) analyse the amount of postoperative long-term weight loss as reflected by BMI change in TKA patients, (2) identify factors associated with increased change in BMI, and to (3) compare changes with BMI trends of a general population. MATERIALS AND METHODS: Overall, 298 TKA patients [198 females; mean age: 65.1 ± 7.9 years, median follow-up 8.8 (interquartile range: 5.9-10.8 years)] were included in the final evaluation and compared with an age group-matched control group from the general population regarding weight trends between 2006 and 2014. Main variable of interest in both cohorts was body mass index (BMI). Linear regression analyses were performed to assess changes in weight and BMI over time between TKA patients and the general population. Furthermore, mixed linear-effects models were constructed to analyse the potential change in BMI independent from age and gender. RESULTS: In TKA patients, a significant drop in BMI by 0.8 ± 3.2 points from postoperative to final follow-up was observed (p < 0.001), with reduction being significant independently from age (p = 0.382), gender (p = 0.310), or revision surgery (p = 0.195). In the general population, likewise a significant BMI-decrease by 0.7 ± 6.1 points was observed between 2006 and 2014, with younger people (p = 0.004) and females (p < 0.001) being more likely to reduce BMI. Yet, BMI-decrease between TKA patients and the general population over time was comparable (p = 0.734). Notably, patients with initially higher BMI were significantly more likely to lose weight postoperatively than normal-weight patients (p < 0.001). CONCLUSIONS: Our results point against the notion that TKA patients lose a considerable amount of weight in comparison to the general population as soon as improved joint function and pain relief have been achieved. Thus, individualized patient education programmes should be reinforced, promoting a healthy lifestyle.

Smokers have increased risk of soft-tissue complications following primary elective TKA.

INTRODUCTION: Smoking has been associated with numerous adverse outcomes following surgical procedures. The purpose of this study was to investigate, whether smoking status at time of surgery influences the outcome of primary TKA. MATERIALS AND METHODS: Six hundred and eighty-one patients who underwent primary TKA between 2003 and 2006 were included in the study. Smoking status was defined as current, former, and never smoker. Complications leading to revisions were assessed until 17 years of follow-up. Functional outcome was evaluated using clinical scores: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analogue Scale (VAS) for pain, Short Form-12 Physical and Mental Component Summaries (SF-12PCS/MCS), and Knee Society Function and Knee Score (KSFS and KSKS). RESULTS: At a mean follow-up of 95 months (± 47 months), 124 complications led to revision surgery. Soft-tissue complications (OR, 2.35 [95% CI 1.08-5.11]; p = 0.032), hematoma formation (OR, 5.37 [95% CI 1.01-28.49]; p = 0.048), and restricted movement (OR, 3.51 [95% CI 1.25-9.84]; p = 0.017) were more likely to occur in current smokers than never smokers. Current smokers were more likely to score higher at KSFS (p < 0.001) and SF-12PCS (p = 0.0197) compared to never smokers. For overall revision, differences were noted. CONCLUSION: Current smoking increases risk of soft-tissue complications and revision after primary TKA, especially due to hematoma and restricted movement. Smoking cessation programs could reduce the risk of revision surgery.

High wear resistance of femoral components coated with titanium nitride: a retrieval analysis.

PURPOSE: The objective of this study was to evaluate the in vivo wear resistance of cobalt-chromium femoral components coated with titanium nitride (TiN). Our null hypothesis was that the surface damage and the thickness of the TiN coating do not correlate with the time in vivo. METHODS: Twenty-five TiN-coated bicondylar femoral retrievals with a mean implantation period of 30.7 ± 11.7 months were subjected to an objective surface damage analysis with a semi-quantitative assessment method. A visual examination of scratches, indentations, notches and coating breakthroughs of the surfaces was performed. The roughness and the coating thickness of the TiN coating were evaluated in the main articulation regions. RESULTS: Narrow scratches and indentations in the range of low flexion angles on the retrieval surfaces were the most common modes of damage. There was no evidence of delamination on the articulation surface but rather at the bottom of isolated severe indentations or notches. An analysis of three retrievals revealed a coating breakthrough in the patellofemoral joint region, resulting from patella maltracking and a dislocation. The arithmetical mean roughness of the TiN surface slightly increased with the implantation period. In contrast, the maximum peak height of the roughness profile was reduced at the condyles of the retrieved components in comparison with new, unused surfaces. No significant association between the coating thickness and implantation period was determined. Moreover, the measured values were retained in the range of the initial coating thickness even after several years of in vivo service. CONCLUSIONS: As was demonstrated by the results of this study, the surface damage to the TiN coating did not deteriorate with the implantation period. The calculated damage scores and the measured coating thickness in particular both confirmed that the TiN coating provides low wear rates. Our findings support the use of wear-resistant TiN-coated components in total knee arthroplasty with the objective of reducing the risk of aseptic loosening. However, in terms of TiN-coated femoral components, particular attention should be paid to a correct patellar tracking in order to avoid wear propagation at the implant.

Is Embolization an Effective Treatment for Recurrent Hemorrhage After Hip or Knee Arthroplasty?

BACKGROUND: Spontaneous recurrent hemorrhage after arthroplasty of the hip or knee is a rare condition. In patients who do not have coagulopathy, the likeliest etiology for hemarthrosis is hypertrophic vascular synovium. Treatments include arthroscopic or open synovectomy, or angiography with embolization; however, because the condition is rare, seldom reported, and debilitating, small case series characterizing the efficacy of any approach are important to allow a collective experience with this condition to emerge. QUESTIONS/PURPOSES: We attempted to (1) determine whether angiography with embolization can prevent recurrent hemarthrosis after hip or knee arthroplasty in a small series of patients with or without coagulopathy, and (2) evaluate complications associated with this intervention. METHODS: Between 2005 and 2014, seven patients presented with spontaneous, recurrent hemarthroses. One patient had polycythemia vera and factor XIII deficiency as underlying illnesses. All patients were treated with selective transarterial embolization, and all had followup at a minimum of 12 months (range, 12-102 months; median, 74 months). Other treatments during this time included hematoma removals and flap operations in one patient, and indications for transarterial embolization included recurrent hemarthrosis. The patients included six men and one woman with a median age of 72 years (range, 61-78 years). Five patients underwent one or more reoperations before transarterial embolization. A diagnostic workup for coagulopathy was performed in all patients; one patient was identified to have polycythemia ruba vera and factor XIII deficiency, however the patient still was treated with transarterial embolization because it was perceived to be the least invasive of available options. No other patients had a diagnosis of coagulopathy. Angiography showed hypervascularity in all patients and a contrast agent showed extravasation in two. Selective transarterial embolization of branches of the internal iliac artery, common femoral artery, deep femoral artery, or the popliteal artery was performed with polyvinyl alcohol particles, microspheres, and/or coils. Patients were followed clinically during 12 to 102 months (median, 74 months) to determine whether the hemorrhages recurred. RESULTS: Technical success was achieved in all patients. No procedure-related complications were reported. On followup, recurrent hemorrhage was reported in one patient who had a diagnosis of coagulopathy before the procedure. He underwent three reinterventions and five reoperations. Three months after initial embolization, a flap procedure was performed. CONCLUSIONS: In a small series of patients with a minimum followup of 1 year, we found selective transarterial embolization to be effective in patients without underlying coagulopathy in preventing recurrences of spontaneous recurrent hematoma or hemarthrosis of the hip and the knee. This condition is rare, therefore comparative trials are unlikely to be done. Because transarterial embolization is relatively low risk and generally well tolerated, we consider it to be a reasonable approach for consideration with other options such as arthroscopic or open synovectomy and revision arthroplasty. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Cementless two-staged total hip arthroplasty with a short term interval period for chronic deep periprosthetic infection. Technique and long-term results.

BACKGROUND: The two-staged exchange with delayed reimplantation is the most reliable method to treat a deep periprosthetic infection after a total hip arthroplasty (THR). Nether uniform recommendations for the technique of cementless reimplantation, nor long term clinical and radiological results are reported. MATERIALS AND METHODS: Our protocol is performed under short term antibiosis with cementless primary porous hip implants to treat chronic deep periprosthetic infections following THR. A retrospective study was performed to evaluate the clinical and radiological long term outcome and the rate of persistent infection of 14 patients. RESULTS: In a five year minimum follow up persistent infection was observed twice in a two-staged revision THR. A dislocation of the hip components was observed in three cases, and could be surgically treated in twice and by wearing a hip-brace in one case. We could not find a loosening of THR components. Three patients had a good or excellent, 11 patients a fair or bad functional outcome. There was a significant correlation between functional outcome and length of interval of prosthesis exand reimplantation. CONCLUSION: Patients have an increased comfort resulting from a short, CRP depending time interval between ex- and reimplantation. Functional outcome is the better the shorter the interval is. The reinfection rate is comparable to those of cemented revision THR's with a long term interval. We could observe advantages in a reduced amount of bone loss and better osseous integration of the uncemented implants, compared to cemented implants reviewing literature. Alterations of acetabular bone stock and soft tissue are responsible for a high rate of instability of the THR. An inaccurate gait pattern is caused by gluteal weakness in the majority of patients. Repeated surgical intervention and duration of immobilization have to be minimalized.

Medium-term analysis of modern ceramic-on-ceramic bearing in THA.

A variety of different bearing surfaces have been used to avoid osteolysis following hip replacement. We report a retrospective review of medium-term results of a modern ceramic-ceramic bearing (Biolox, CeramTec, Plochingen, Germany) and uncemented components (Alpha Cera Fit Alphanorm, Lassnitzhohe, Austria) in 107 hip arthroplasties. The clinical outcome based on serial radiographs and scoring was assessed with a minimum follow-up of 7 years (mean, 7, 6 years; range, 7, 1-8, 3 years). The average age of the patients at surgery was 64, 6 + 11, 7 years (range: 21-88 years). The mean Harris hip score was 90, 4 (range, 84, 7-99, 2). Three patients with an extra long femoral neck experienced fracture of the ceramic femoral head, resulting in cessation of use of this combination. Radiological evaluation did not reveal any signs of lysis or loosening. Massive heterotopic ossification was seen in three patients. Medium-term follow-up showed excellent clinical and radiological results. Continued follow-up will be required to determine if this ceramic-on-ceramic bearing is associated with extended survivorship.

[Modern ceramic-on-ceramic bearings in total hip arthroplasty]. / Moderne Keramik-keramik-Gleitpaarung in der Hüftgelenksendoprothetik.

OBJECTIVE: Ceramic bearings in total hip arthroplasty were already employed three decades ago, but due to high failure rates, their application decreased. However, improved material and design have led to their regaining popularity. The present study evaluates the short-term results of a modern ceramic-on-ceramic bearing in total hip prosthesis. METHODS: 229 total hip arthroplasties, alpha Cera Fit, were implanted in 227 patients over a 12-month period. A follow-up, at a minimum of 36 months, was performed. In addition to demographics, the Harris Hip-Score was used to calculate the clinical results and radiological control was also carried out. RESULTS: The mean age at the time of surgery was 64.6 (+/- 11.7) years. There was no case of deep infection, four patients had superficial wound healing disorders. 197/227 patients with 199 total hip arthroplasties were available for follow-up, with a mean follow-up time of 42 (+/- 2.9) months. The mean Harris Hip-Score was 94.3 (+/- 6.8). Radiological evaluation did not reveal any signs of lysis or loosening. Massive periarticular calcification was seen in three patients, with one that needed surgical debridement. CONCLUSION: The presented modern ceramic-on-ceramic bearings in total hip arthroplasty show excellent clinical and radiological short-term results. The material-related complications reported in former publications were no longer seen.