Radiographic Cone Zone Classification of Metaphyseal Cone Fixation in Revision Total Knee Arthroplasty.

Background: No objective radiographic scoring system exists to classify metaphyseal cone stability. Our purpose was to create a novel, systematic method to radiographically evaluate metaphyseal cone fixation based on radiographic findings suggestive of cone stability. Methods: A retrospective analysis was conducted of revision total knee arthroplasty patients (6/2015-12/2017) using porous titanium femoral or tibial metaphyseal cones in conjunction with short cemented stems (50 mm-75 mm). Minimum follow-up was 2 years. Survivorship free of aseptic loosening and reoperation, as well as radiographic evaluation using a novel cone zone scoring system were analyzed. Results: Forty-nine revision total knee arthroplasties were included in the study (12 femoral, 48 tibial cones), the majority, performed for aseptic loosening (25/49, 51%). Median follow-up was 39 months (range 25-58). Using the radiographic cone zone scoring method, >90% of all femoral cones were classified as likely stable or stable with strong, statistically significant intraclass correlations between all 3 reviewers. Similarly, >97% of all tibial cones were classified as likely stable or stable, with moderate, statistically significant intraclass correlations between all 3 reviewers. Only 1 femoral and 1 tibial cone were considered at risk of loosening. The study sample demonstrated 100% survivorship free of revision for aseptic loosening without evidence of radiographic loosening in any case. Conclusions: Using a novel systematic cone zone scoring and classification method, the overwhelming majority of femoral and tibial cones were classified as likely stable or stable, with no identified cases of aseptic loosening or related revision. Further studies are needed to validate this objective classification method.

Mid-term Follow Up of a Highly Porous Acetabular Component for Primary Total Hip Arthroplasty.

INTRODUCTION: As implant technology has continued to improve over the past decade, there has been an increase in the utilization of highly porous metal substrate acetabular components for primary total hip arthroplasty (THA). These implants have several theoretical benefits including a lower modulus of elasticity, which may result in a reduction in stress shielding, a higher coefficient of friction, which may enable better initial implant fixation, as well as higher porosity that may facilitate improved biological fixation. Although these components are implanted frequently, there are some studies that have posed concerns regarding radiographic evidence of loosening. Therefore, the purpose of this study was to assess: 1) The quality of fixation of porous metal acetabular components based on radiographs; 2) clinical outcomes; and 3) revision rates. MATERIALS AND METHODS: A total of 159 patients (169 hips) who had undergone a primary THA utilizing a porous metal primary acetabular cup with minimum two-year follow up were assessed. The study cohort consisted of 51% women, had a mean age of 65 years (range, 30 to 92 years), a mean body mass index (BMI) of 29kg/m2 (range, 15 to 54), and a mean follow up of approximately four years (range, three to six years). Acetabular revision for component failure was documented. Radiographic assessments were independently performed by two fellowship-trained arthroplasty surgeons to determine implant stability and radiolucencies. Clinical evaluations were made by assessing the hip disability and osteoarthritis outcome score (HOOS-Jr) survey scores. Failure was defined as the need to revise the acetabular component, for either septic or aseptic pathology. RESULTS: At final follow up, one patient had definitive loosening, one had probable loosening, and three patients had possible loosening. Only 3.0% had radiolucencies or radiosclerotic lesions in at least one zone. Of these patients, three developed progressive radiolucencies. All patients achieved excellent postoperative HOOS-Jr scores, and no significant differences were noted between patients who did not have loosening compared to patients who had possible or probable loosening. Only two patients underwent revision for aseptic loosening of the cup (success rate for this implant was 98.8% [2/169]). DISCUSSION: There is a paucity of studies focused on the results of this porous metal substrate acetabular component, with some of the current literature reporting conflicting outcomes. Our study reported a low acetabular revision rate of only 1.2% at an approximate mean follow up of four years. The incidence of radiolucencies and progressive radiolucencies were lower (3.0%) than has been found in some studies. Overall, the results of this study support the utilization of this acetabular component in appropriately indicated patients. CONCLUSION: These data show a low rate of acetabular revision at mean four-year follow up.

Local Infiltration Analgesia With Liposomal Bupivacaine Improves Pain Scores and Reduces Opioid Use After Total Knee Arthroplasty: Results of a Randomized Controlled Trial.

BACKGROUND: Local infiltration analgesia (LIA) with liposomal bupivacaine (LB) in patients undergoing total knee arthroplasty (TKA) has yielded mixed results. The PILLAR study, which was designed to minimize limitations associated with previous studies, compared the effects of LIA with or without LB on pain scores, opioid consumption, including proportion of opioid-free patients, time to first opioid rescue, and safety after primary unilateral TKA. METHODS: Patients (N = 140) were randomized to LIA with LB 266 mg/20 mL (admixed with bupivacaine HCl 0.5%, 20 mL) or LIA with bupivacaine HCl 0.5%, 20 mL. Standardized infiltration techniques and a standardized multimodal pain management protocol were used. The coprimary efficacy endpoints were area under the curve (AUC) of visual analog scale pain intensity scores 12-48 hours (AUC12-48) postsurgery and total opioid consumption 0-48 hours postsurgery. RESULTS: Mean AUC12-48 of visual analog scale pain intensity score was 180.8 with LB and 209.3 without LB (least squares [LS] mean treatment difference -26.88, P = .0381). LS mean total opioid consumption 0-48 hours postsurgery was 18.7 mg with and 84.9 mg without LB (LS ratio 0.220, P = .0048). Significant differences in favor of LB were observed for the percentage of opioid-free patients (P < .01) and time to first opioid rescue (P = .0230). Treatments were similarly well tolerated. CONCLUSION: This study provides data on LIA with LB administered using optimal techniques specific to TKA. In this setting, LIA with LB significantly improved postsurgical pain, opioid consumption, and time to first opioid rescue, with more opioid-free patients and no unexpected safety concerns.

Impact of Inpatient Versus Outpatient Total Joint Arthroplasty on 30-Day Hospital Readmission Rates and Unplanned Episodes of Care.

This article describes a study comparing 30-day readmission rates between patients undergoing outpatient versus inpatient total hip (THA) and knee (TKA) arthroplasty. A retrospective review of 137 patients undergoing outpatient total joint arthroplasty (TJA) and 106 patients undergoing inpatient (minimum 2-day hospital stay) TJA was conducted. Unplanned hospital readmissions and unplanned episodes of care were recorded. All patients completed a telephone survey. Seven inpatients and 16 outpatients required hospital readmission or an unplanned episode of care following hospital discharge. Readmission rates were higher for TKA than THA. The authors found no statistical differences in 30-day readmission or unplanned care episodes.

Unloader Bracing for Knee Osteoarthritis: A Pilot Study of Gait and Function.

Knee osteoarthritis (OA) is increasing in the United States, and some have proposed the use of unloader bracing as an adjunct to current standard treatments. Our purpose was to evaluate outcomes of this brace for the treatment of knee osteoarthritis compared with standard non-operative treatment. Specifically, we evaluated: (1) pain relief, (2) objective functional improvement, (3) subjective functional improvement, (4) quality of life, (5) isokinetic quadriceps muscle strength, and (6) gait changes. A prospective, randomized, study was performed on 18 patients who had Kellgren-Lawrence grade 1 and 2 osteoarthritis. Patients were randomized to receive either standard treatment or an unloader brace. End points evaluated included: functional tests, Knee Society Score, Short Form 36 (SF-36) health survey, Visual Analog Scale (VAS) for pain, Lower Extremity Functional Scale, isokinetic quadriceps and hamstring muscle strength, and 3-dimensional gait analysis. There were no differences between cohorts in evaluation of pain (VAS), objective functional tests, subjective functional outcomes (Knee Society Scores and LEFS), quality of life assessment with SF-36, isokinetic quadriceps and hamstring muscle strength, and gait parameters. The use of unloader brace demonstrated similar improvements compared with standard treatments for knee osteoarthritis, and we believe that it can be a beneficial or equivalent adjunct to continuum of care for the treatment for knee osteoarthritis.

Role of Surgical Dressings in Total Joint Arthroplasty: A Randomized Controlled Trial.

We conducted a randomized controlled trial to compare efficacy of an occlusive antimicrobial barrier dressing and a standard surgical dressing in patients who underwent primary total joint arthroplasty. Two hundred sixty-two patients were randomized to receive either an occlusive dressing or a standard dressing. Wounds were closed in identical fashion. Outcomes included wound complications, dressing changes, and patient satisfaction. With use of occlusive dressing (vs standard dressing), wound complications (including skin blistering) were significantly (P = 0.15) reduced; there were significantly (P < .0001) fewer dressing changes; and patient satisfaction was significantly (P < .0001) higher. Use of occlusive dressings can reduce wound complications and promote wound healing after total joint arthroplasty.

Predicting Blood Loss in Total Knee and Hip Arthroplasty.

Marked blood loss during lower extremity total joint arthroplasties may lead to higher rates of transfusion, which may negatively affect surgical outcomes and yield greater complication rates. It is therefore ideal to identify factors that may increase the likelihood of blood loss, so they can be modified. From this review, it can be concluded that preoperative anemia, older age, multiple comorbidities, increased operative time, and use of postoperative anticoagulation may lead to higher blood loss and transfusion rates, although the influence of other factors remains controversial.

Long-Term Survivorship and Clinical Outcomes Following Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is one of the most successful commonly performed orthopedic procedures; as such, the purpose was to assess the long-term outcomes and survivorship of primary TKAs with a dual-radius prosthesis. We evaluated 125-patients (145-knees), with a mean age of 63 years (37-90 years) for a mean 11-year follow-up (10-13 years). Outcomes were assessed with KSS, UCLA, SF-36, satisfaction scores, and aseptic survivorship analysis. At 10-year follow-up, the UCLA (6-points), KSS objective (84-points) and functional (73-points), SF-36 physical (41-points) and mental (51-points), and patient satisfaction (14-points) scores were reported to be good to excellent. The 10-year Kaplan-Meier survivorship rate was 99%; one TKA demonstrated radiographic loosening. At a minimum 10-year follow-up, this device demonstrated satisfactory outcomes and outstanding aseptic-survivorship rates.

Genetically modified chondrocytes expressing TGF-ß1: a revolutionary treatment for articular cartilage damage?

INTRODUCTION: Currently, joint arthroplasty remains the only definitive management of osteoarthritis, while other treatment modalities only provide temporary and symptomatic relief. The use of genetically engineered chondrocytes is currently undergoing clinical trials. Specifically, it has been designed to induce cartilage growth and differentiation in patients with degenerative arthritis, with the aim to play a curative role in the disease process. AREAS COVERED: This treatment involves the incorporation of TGF-ß1, which has been determined to play an influential role in chondrogenesis and extracellular matrix synthesis. Using genetic manipulation and viral transduction, TGF-ß1 is incorporated into human chondrocytes and administered in a minimally invasive fashion directly to the affected joint. Following a database literature search, we evaluated the current evidence on this product and its outcomes. Furthermore, we also briefly reviewed other treatments developed for chondrogenesis and cartilage regeneration for comparison. EXPERT OPINION: This treatment method has sustained positive effects on functional outcomes and cartilage growth in initial trials. It allows administration in a minimally invasive manner that does not require extended recovery time. Although several treatment modalities are currently under investigation and appear promising, we hope that these effects can be sustained in further studies. Ultimately, we anticipate that the results may be reproducible in many clinical settings and allow us to effectively treat cartilage damage in patients with degenerative arthritis.

Determining Health-Related Quality-of-Life Outcomes Using the SF-6D Preference-Based Measure in Patients Following Total Knee Arthroplasty.

The SF-6D, a health-related quality-of-life measure, assigns value to patients' perception of their health. We determined SF-6D values of 844 TKA patients, deduced clinical relevance of value changes using effect size, and compared these to clinical and functional improvements 6weeks, 3months, and 1 through 5years post-operatively. The SF-6D significantly improved at all follow-ups after 6weeks. The effect size indicated clinical relevance at every follow-up. The KSS improved at all follow-ups (+43, +51, +56, +57, +57 points), and LEAS scores improved at follow-ups after 6weeks (+1 point at 3months, +2 points thereafter), correlating with SF-6D changes. Deducing utility scores facilitates cost analyses, allowing clinicians to deduce quality-adjusted life-years and economic impacts of treatments.

Clinical & radiographic outcomes of cemented vs. diaphyseal engaging cementless stems in aseptic revision TKA.

Modular revision systems have become standard in revision TKAs. However, the type of stem fixation remains controversial. The purpose of this study is to compare the incidence of failure between cemented and diaphyseal engaging cementless stems in aseptic revision TKAs. We performed a multicenter retrospective review of 82 revision TKAs performed for aseptic failure. Follow-up averaged 76 and 121 months for the cemented and cementless groups respectively. Re-revision and radiographic failure rates for both femoral and tibial stems were similar between groups. We found similar improvements in knee society scores between the groups. At midterm follow-up, we found no difference in failure rates between the groups. Both types of stem appear to provide reliable fixation and are viable options in revision TKAs.

Are cementless stems more durable than cemented stems in two-stage revisions of infected total knee arthroplasties?

BACKGROUND: The routine use of stems in revision TKA improves survival rates by enhancing the stability of the prosthesis. The ideal method of stem fixation (cemented or uncemented) in two-stage reimplantation remains controversial. QUESTIONS/PURPOSES: The purpose of this study was to answer the following questions: (1) Are rerevision rates for aseptic loosening comparable between cemented stems and uncemented stems in two-stage reimplantation? (2) Is the reinfection rate comparable between antibiotic-impregnated cemented stems and uncemented stems for two-stage reimplantation? (3) Are there any differences in Knee Society radiographic scores between stem techniques? METHODS: A retrospective analysis was performed in all patients who underwent two-stage reimplantation between 1990 and 2010 at Anderson Orthopaedic Research Institute (AORI) and OrthoCarolina (OC). One hundred fourteen patients with 228 stems met the inclusion criteria. Of these 228 stems, 102 stems were cemented and 126 stems were uncemented. The indication for stem fixation was largely institution specific; AORI used cementless stems 92% (118) of the time, whereas OC used a cemented stem 92% (92) of the time. A 2-year minimum radiographic and clinical followup was required for inclusion into the study. Radiographic evaluations were performed using a modification of the Knee Society radiographic score. RESULTS: Rerevision rates for aseptic loosening were comparable with three cemented and three cementless stem constructs. The reinfection rate was also comparable between cemented and cementless stems (p = 0.86). Using post hoc analysis, 32% of cemented stems were radiographically classified as loose or closely observe (33 of 102) compared with 17% of the cementless stem group (21 of 126; p = 0.006). Patients with good bone quality had a significantly lower rate of radiographic loosening compared with patients with poor bone quality (p = 0.01). There was no significant correlation with radiographic loosening and level of constraint (p = 0.90) or use of articulating versus static antibiotic spacer (p = 0.06). CONCLUSIONS: In this retrospective study, cementless diaphyseal-engaging stems had a lower rate of radiographic failure than did cemented stems in two-stage reimplantation. Reinfection rates remain similar despite the absence of antibiotic cement in the cementless constructs. At this time we believe the use of hybrid, cementless diaphyseal-engaging stems should be considered as a possible option at the time of reimplantation.

Abductor dysfunction and related sciatic nerve palsy, a new complication of metal-on-metal arthroplasty.

The optimal bearing for use in young patients with hip arthritis remains elusive. Current options include metal-on-cross-linked polyethylene, ceramic-on-cross-linked polyethylene, ceramic on ceramic, and metal on metal. Each of these bearing couples has advantages and disadvantages. Metal-on-metal designs allow the use of large heads that decrease impingement and improve stability. This fact has made this bearing an attractive option for surgeons and patients alike. This case report will illustrate a severe adverse reaction to metal debris with necrosis of soft tissues and subsequent damage to the sciatic nerve.

Differences between the sexes in the anatomy of the anterior condyle of the knee.

BACKGROUND: Claims that there are dramatic differences in anterior condylar anatomy between the sexes have led to the design of total knee implants with thinner anterior condyles specifically for use in women. We had observed, in our patients, differences in anterior condylar anatomy that appeared to be highly variable and dependent on the size, height, and ethnicity of the patient as well as his or her sex. Because of this observed variability, we sought to determine if differences in anterior condylar anatomy between the sexes actually exist. METHODS: Two hundred and twelve randomly selected magnetic resonance images (112 of men and 100 of women) were evaluated. The anterior condyle was defined as the area of bone anterior to the anterior femoral cortex, 10 mm above the joint line. The medial and lateral heights of the anterior condyles were measured in millimeters directly from magnetic resonance imaging data obtained in two planes. The so-called aspect ratio was calculated to determine whether patient size had an effect on the size of the anterior condyles. RESULTS: On the basis of the numbers available, there was no significant difference (p = 0.16) between the sexes with regard to lateral condylar height. The average difference was only 0.5 mm. There was a significant difference (p = 0.001) between men and women with regard to medial condylar height. However, the average difference was only 1.1 mm. While the difference between the sexes with regard to anterior condylar height was nominal, the measurements were highly variable regardless of sex. On the basis of the numbers available, there were no significant differences between men and women with regard to the condylar aspect ratios. CONCLUSIONS: The difference in anterior condylar anatomy is mentioned as one of three reasons for the need for a so-called gender-specific knee implant. The aspect ratio reported here, which is a surrogate for patient size, seems to negate any difference in anterior condylar anatomy based on sex. We have shown that anterior condylar anatomy is highly variable regardless of sex. We believe that implants as well as surgical techniques should be designed with the variability of anterior condylar anatomy taken into account and with an attempt to reproduce such anatomy regardless of sex.