Central cone design demonstrates greater micromotion compared to keel design in cementless tibial baseplates: A biomechanical analysis.

PURPOSE: The purpose of this study was to compare micromotion of two new cementless tibial baseplates to a cementless design with well-published clinical success. METHODS: Three cementless tibial baseplate designs (fixed-bearing [FB] with keel and cruciform pegs, rotating-platform with porous central cone and pegs, FB with cruciform keel and scalloped pegs) were evaluated on sawbone models. Loading was applied to the baseplate at a rate of 1 Hz for 10,000 cycles, which represents 6-8 weeks of stair descent. This time frame also represents the approximate time length for the induction of biologic fixation of cementless implants. Compressive and shear micromotion at the sawbone-implant interface were measured. RESULTS: At the end of the loading protocol, the central cone rotating-platform design exhibited greater micromotion at the anterior (p < 0.001), posterior (p < 0.001) and medial locations (p = 0.049) compared to the other two implants. The central cone design also exhibited greater translational micromotion in the sagittal plane at the medial (p = 0.001) and lateral locations (p = 0.034) and in the coronal plane anteriorly (p = 0.007). CONCLUSION: The cementless central cone rotating-platform baseplate demonstrated greater vertical and translational micromotion compared to the two FB baseplates with a keel underloading. This may indicate lower initial mechanical stability in implants without a keel, which possibly affects osseointegration. The implication of this is yet unknown and requires further long-term clinical follow-up to correlate these laboratory findings. LEVEL OF EVIDENCE: V (biomechanical study).

Femoral internal torsion greater than twenty-five degrees and/or external tibial torsion greater than thirty degrees as measured by computed tomography are threshold values for axial alignment correction in patellofemoral instability.

OBJECTIVES: Patellofemoral instability (PFI) has multiple predisposing anatomic factors, including ligamentous hyperlaxity, coronal and axial malalignment, patella alta, trochlea dysplasia, excessive lateral patellar tilt, and excessive lateral Q vector. Yet, few studies have analyzed surgical thresholds for performing axial alignment corrective osteotomies in the treatment of PFI and patella maltracking. The objective of this systematic literature review was to determine if there is a threshold for axial plane alignment that triggers surgical correction for the treatment of patellar instability in the published literature. METHODS: Using a predetermined search strategy, a systematic literature search of 10 major databases and gray literature resources was completed. Only studies reporting on patellar instability and outcomes were included. Radiologic indications, additional procedures, outcomes, and complications were reported. Titles and abstracts were screened, and full-text manuscripts were then selected and extracted. Variables related to radiographic and clinical parameters, patient demographics, surgery performed, surgical correction, complications, and reoperations were recorded preoperatively and postoperatively. RESULTS: A total of 1132 abstracts and titles were screened by two reviewers, yielding 15 eligible studies. The reported threshold identified in our study for axial plane alignment that triggers surgical correction in most of the published literature when discussing PFI was either tibial torsion greater than 30° and/or femoral anteversion greater than 25°. Following rotational osteotomy of one or both long bones, one study (7%) reported improvements in tubercle-sulcus angle, two studies (13%) reported improvements in femoral-tibial angle, and four studies (27%) reported decreases in tibial torsion. For patient-reported outcomes, seven studies (47%) reported improvement in the Kujala score, five studies (33%) reported postoperative improvement in Lysholm, and four studies (27%) reported improvement in the International Knee Documentation Committee (IKDC) score. Nine studies (60%) reported preoperative femoral anteversion; however, only two studies compared pre- and post-operative values (one study reported a decrease in anteversion and another study reported an increase in anteversion). CONCLUSION: When treating PFI, the reported threshold for axial plane alignment that triggers surgical correction in most of the published literature was tibial torsion greater than 30° and/or femoral anteversion greater than 25° as measured by CT. However, there is no consensus on the axial alignment measurement technique. LEVEL OF EVIDENCE: III.

Major complications after total hip arthroplasty with the direct anterior approach at a high-volume Ontario tertiary care centre.

BACKGROUND: The rate of major surgical complications for high-volume orthopedic surgeons using the direct anterior approach (DAA) in Ontario, Canada, is not known. The purpose of this study was to investigate the rate of major surgical complications after total hip arthroplasty (THA) using DAA performed by experienced orthopedic surgeons at a high-volume tertiary care centre in Ontario. METHODS: We conducted a retrospective cohort review of primary THA through DAA performed by 2 experienced fellowship-trained surgeons at an academic hospital in London, Ontario, between Jan. 1, 2012, and May 1, 2019. We excluded the first 100 cases to allow for surgeon learning curves. We recorded major surgical complications (intraoperative events, postoperative periprosthetic fractures, dislocation requiring closed or open reduction, implant failure [aseptic loosening or subsidence], early (< 6 wk) deep wound infection requiring irrigation and débridement, late (≥ 6 wk) deep wound infection requiring irrigation and débridement, and wound complications [wound dehiscence, stitch abscess, erythema, hematoma or seroma]) within 1 year of THA. RESULTS: A total of 875 primary DAA THA procedures were included. The rates of surgical complications were 0.9% for intraoperative events, 1.5% for postoperative periprosthetic fractures, 0.8% for implant failure, 0.7% for early deep wound infection, 0.1% for late deep wound infection and 3.2% for wound complications; there were no cases of dislocation. The rate of revision for implant failure within 1 year was 0.1%. Male sex was associated with a greater risk of implant failure (p = 0.01), and having a higher body mass index was associated with both increased rates of infection (p < 0.01) and having a wound complication (p < 0.01). CONCLUSION: Intraoperative events, postoperative periprosthetic fractures, implant failure, deep wound infection and wound complications accounted for the major surgical complications within 1 year of THA through DAA. The low revision rate suggests that DAA is a safe approach for THA.

Quantification of trunnion damage in a series of intact total hip arthroplasty femoral stems previously identified to be at risk of catastrophic failure.

BACKGROUND: Corrosion at the head-neck junction of femoral stems is a rare complication of total hip arthroplasty (THA) with manifestations ranging from subclinical wear to failure. Prior studies have identified a single femoral component design with an increased propensity for catastrophic trunnion failure. The purpose of the present study was to quantify trunnion damage of this femoral component retrieved from patients undergoing revision THA for non-trunnionosis indications. METHODS: 24 femoral components from a single manufacturer were identified for study inclusion. Each prosthesis underwent stereomicroscopic inspection. Corrosion and fretting scores were assigned per the Goldberg criteria to quadrants of the trunnion. Material loss was calculated based on cone angles across trunnion quadrants. This was carried out using a coordinate measuring machine that digitised each trunnion surface. Stems were compared to a series of femoral stems with the same trunnion design. RESULTS: 20 of the 24 (83%) trunnions demonstrated corrosion, all 24 trunnions demonstrated fretting. Corrosion scores did not statistically differ with respect to trunnion zone (p = 0.53), while fretting scores were higher in the inferior compared to the superior zones (p < 0.001). There was no significant difference in cone angles assessing material loss between stems (p = 0.25). CONCLUSIONS: Evidence of trunnion damage was observed in each stem retrieved for non-trunnionosis revision. Fretting occurred more frequently about the inferior quadrants. However, digitised trunnion shapes were similar between compared stems exhibiting no material loss. Therefore, it is possible that previous reports of trunnion failures for this implant are not a systemic issue, and that further investigation is required.

Total Hip Arthroplasty in Patients Aged 40 to 60 Years Old: A Population-Based Study.

BACKGROUND: Contemporary total hip arthroplasty (THA) has resolved many implant longevity concerns in younger patients. Patients in their fourth and fifth decades of life are projected to be the fastest-growing demographic of THA patients. We aimed to assess this demographic to: 1) evaluate the rate of THA over time; 2) evaluate the cumulative incidence of revision; and 3) identify risk factors for revision. METHODS: A retrospective population-based study of patients between 40 and 60 years old undergoing primary THA was conducted using administrative data from a large clinical data repository. A total of 28,414 patients were included for analysis with a mean age of 53 years (range, 40-60 years) and median follow-up of 9 years (range, 0-17 years). Linear regressions were used to assess annual rates of THA in this cohort over time. Kaplan-Meier analysis was used to determine cumulative incidence of revision. Multivariate Cox proportional hazards models were used to determine association of variables with revision risk. RESULTS: The annual rate of THA in our population increased by 60.7% over the study period (P < .0001). Cumulative incidence of revision was 2.9% at 5 years and 4.8% at 10 years. Younger age, women, non-osteoarthritis diagnosis, medical complications, and annual surgeon volume ≤ 60 THA were associated with increased revision risk. CONCLUSION: Demand for THA continues to dramatically increase in this cohort. Risk of revision was low but multiple risk factors were identified. Future studies will help delineate the effect of these variables on revision risk and assess implant survivorship beyond 10 years.

Effects of Surgical Approach and Tourniquet Use on Patient-Reported Outcomes Following Total Knee Arthroplasty: A Pilot Randomized Clinical Trial.

Introduction: Total knee arthroplasty (TKA) is one of the most successful procedures for the treatment of severe knee osteoarthritis. Various surgical approaches have been investigated in the hopes of improving postoperative outcomes. Two include the medial parapatellar (standard) and midvastus. As the midvastus approach does not disrupt the extensor mechanism, it may be advantageous for functional recovery, however length of stay and long-term function are similar between approaches. Tourniquet use during TKA has conflicting results in the literature. We hypothesized that a future trial comparing outpatient versus standard TKA could appropriately use either surgical approach with or without a tourniquet. Therefore, the objective of this pilot randomized trial was to compare postoperative pain, function, quality of life, and satisfaction between patients who underwent a medial parapatellar or midvastus approach for TKA ± tourniquet use. Methods: We conducted a randomized trial with a two-by-two factorial design to compare the medial parapatellar to the midvastus surgical approach for TKA ± tourniquet use. The Short Form-12 (SF-12), Western Ontario McMaster Osteoarthritis Index (WOMAC), and Knee Society Score (KSS) were collected at baseline, postoperatively at two, six, 12 weeks, and one year. Results: Eighty-three patients were included. Postoperative WOMAC scores were statistically but not clinically higher at six weeks and three months in favour of no tourniquet use. There were no differences in postoperative WOMAC scores between approaches. Short Form-12 and KSS scores increased in both groups with no significant differences postoperatively (p > 0.05). Conclusion: There were no clinically significant differences in postoperative pain, function, quality of life, or satisfaction between surgical approaches or whether a tourniquet was used. As such, both surgical approaches ± tourniquet use are safe and reliable. We believe a future larger randomized trial could likely incorporate either surgical approach or tourniquet preferences without significant impact on patient reported outcomes.

Ultrasound-Guided Motor-Sparing Knee Blocks for Postoperative Analgesia Following Total Knee Arthroplasty: A Cost Analysis.

Background: We recently performed a clinical trial comparing motor sparing blocks (MSB) to periarticular infiltration (PAI) following total knee arthroplasty (TKA). We found that MSBs provided longer analgesia (8.8 hours) than PAI with retention of quadriceps strength, and with similar function, satisfaction, and length hospital stay. However, its potential increased cost could serve as a barrier to its adoption. Therefore, our aim was to compare the costs of MSBs to PAI following TKA. Methods: We conducted a retrospective review of data from our previous RCT. There were 82 patients included in the RCT (n = 41 MSB group, n = 41 PAI group). We compared the mean total costs associated with each group until hospital discharge including intervention costs, health-care professional service fees, intraoperative medications, length of stay, and postoperative opioid use. Results: Seventy patients were included (n = 35 MSB group, n = 35 PAI group). The mean total costs for the MSB group were significantly higher ($1959.46 ± 755.4) compared to the PAI group ($1616.25 ± 488.33), with a mean difference of $343.21 (95% CI = $73.28 to $664.11, p = 0.03). The total perioperative intervention costs for performing the MSB was also significantly higher; however, postoperative inpatient costs including length of stay and total opioid use did not differ significantly. Conclusion: Motor sparing blocks had significantly higher mean total and perioperative costs compared to PAI with no significant difference in postoperative inpatient costs. However, its quadricep sparing nature and previously demonstrated prolonged postoperative analgesia can be used to facilitate an outpatient TKA pathway thereby offsetting its increased costs.

Early radiographic outcomes following deltoid ligament repair in bimalleolar equivalent ankle fractures.

BACKGROUND: Indications for deltoid ligament repair in bimalleolar equivalent ankle fractures are unclear. This study compared radiographic outcomes in bimalleolar equivalent ankle fractures undergoing open reduction internal fixation (ORIF) +/- deltoid ligament repair. METHODS: A retrospective review of 1024 ankle fractures was performed. Bimalleolar equivalent injuries treated with ORIF +/- deltoid ligament repair were included. Radiographic assessment was performed preoperatively, and at three months postoperatively. RESULTS: One hundred and forty-seven ankle fractures met inclusion criteria with 46 undergoing deltoid ligament repairs. There was a significant decrease in medial clear space (1.93 ± 0.65 mm vs. 2.26 ± 0.64 mm, p = 0.01), and tibiofibular clear space (3.89 ± 1.20 mm vs. 4.87 ± 1.37 mm, p = 0.0001) at 3 months postoperative in the deltoid repair group compared to the no repair group. When syndesmotic fixation was performed, there were no differences between groups. CONCLUSION: Deltoid ligament repair in bimalleolar equivalent ankle fractures resulted in reduced medial clear space, and tibiofibular clear space in the early postoperative period. These differences were small and remained within established normal limits. LEVEL OF CLINICAL EVIDENCE: Level III, retrospective cohort study.

Cartilage Restoration in the Adolescent Knee: a Systematic Review.

PURPOSE OF REVIEW: The purpose of this systematic review was to assess the outcomes and complications of described cartilage restoration techniques for cartilage defects (grades I to IV) in the adolescent knee. RECENT FINDINGS:  Eleven studies satisfied the inclusion criteria comprising 307 patients with a mean follow-up of 4.6 years (range 1-18.9 years). Study patients were treated with autologous chondrocyte implantation (ACI) (n = 98, mean age 16.0), microfracture (MFx) (n = 36, mean age 15.4), internal fixation (n = 71, mean age 13.1), osteochondral allograft (OCA) transplantation (n = 78, mean age 16.4), and cartillage and excision (n = 24; mean age 14.2). ACI, MFx, OCA transplantation, and internal fixation showed significant improvement in knee functionality scores. The overall complication rate was 10.6% (n = 31). OCA transplantation had the highest complication rate (26.9%; n = 21/78). In summary, our review shows that ACI was the most commonly used technique. Furthermore, ACI, MFx, OCA transplantation, and internal fixation show the most promise in treating the adolescent population due to positive postoperative functional outcomes and low complication rates. However, future studies with large sample sizes, standardized outcome documentation, and long-term follow-up are required to confirm these preliminary results.

Predictors of Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement: A Systematic Review.

BACKGROUND: The benefits of hip arthroscopic surgery in the setting of femoroacetabular impingement (FAI) have been well established; however, some patients may experience a greater degree of improvement than others. Identifying positive and negative predictors of outcomes would assist the orthopaedic surgeon's management algorithm for patients with FAI. PURPOSE/HYPOTHESIS: The objective of this systematic review was to identify demographic, radiographic, and other operative predictors of positive and negative outcomes after hip arthroscopic surgery for patients with FAI. It was hypothesized that factors including FAI morphology, age, body mass index (BMI), sex, dysplasia, articular cartilage damage, radiographic joint space, and labral treatment would predict outcomes after hip arthroscopic surgery. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: This systematic review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three databases (Embase, PubMed, and Ovid [MEDLINE]) were searched on May 19, 2018, using terms including "hip," "arthroscopy," and "FAI." Studies were screened and data extracted in duplicate. RESULTS: A total of 39 studies were included in this systematic review, comprising 9272 hips with a mean age of 36.5 years (47.2% female). Younger age, male sex, lower BMI (<24.5 kg/m2), Tönnis grade 0, and preoperative pain relief from diagnostic intra-articular hip injections predicted positive outcomes. Female sex, older age (>45 years), longer duration of preoperative symptoms (>8 months), elevated BMI, increased Tönnis grade (≥1), chondral defects, decreased joint space (≤2 mm), increased Kellgren-Lawrence grade (>3), increased lateral center-edge angle (LCEA), and undergoing labral debridement alone were predictors of negative outcomes. CONCLUSION: In patients with FAI, younger age, male sex, lower BMI (<24.5 kg/m2), Tönnis grade 0, and pain relief from preoperative intra-articular hip injections are significantly more likely to achieve positive outcomes after hip arthroscopic surgery. On the other hand, older age (>45 years), female sex, elevated BMI, osteoarthritic changes, decreased joint space (≤2 mm), chondral defects, increased LCEA, and undergoing labral debridement compared with labral repair are associated with negative outcomes.

Ultrasound-Guided Motor-Sparing Knee Blocks for Postoperative Analgesia Following Total Knee Arthroplasty: A Randomized Blinded Study.

BACKGROUND: Pain following total knee arthroplasty (TKA) is often severe and can inhibit rehabilitation. Motor-sparing analgesic techniques such as periarticular infiltrations and adductor canal blocks have been popularized for knee analgesia since they preserve motor strength and permit early mobilization. Our primary objective was to compare the duration of analgesia from motor-sparing blocks with that of a standard periarticular infiltration. We used the time to first rescue analgesia as the end point. METHODS: We randomized 82 patients scheduled for elective TKA to receive either the preoperative motor-sparing block (0.5% ropivacaine, 2.5 µg/mL of epinephrine, 10 mg of morphine, and 30 mg of ketorolac) or intraoperative periarticular infiltration (0.3% ropivacaine, 2.5 µg/mL of epinephrine, 10 mg of morphine, and 30 mg of ketorolac). For the motor-sparing block, we modified the ultrasound-guided adductor canal block by combining it with a lateral femoral cutaneous nerve block and posterior knee infiltration. The patients, surgeons, anesthetists administering the blocks, and outcome assessors all remained blinded to group allocation. Our primary outcome was duration of analgesia (time to first rescue analgesia). Secondary outcomes included quadriceps strength, function, side effects, satisfaction, and length of hospital stay. RESULTS: The duration of analgesia was significantly longer (mean difference, 8.8 hours [95% confidence interval = 3.98 to 13.62], p < 0.01) for the motor-sparing-block group (mean [and standard error], 18.1 ± 1.7 hours) compared with the periarticular infiltration group (mean, 9.25 ± 1.7 hours). The infiltration group had significantly higher scores for pain at rest for the first 2 postoperative hours and for pain with knee movement at 2 and 4 hours. There were no significant differences between groups with regard to any other secondary outcomes. CONCLUSIONS: In patients undergoing a TKA, a motor-sparing block provides longer analgesia than periarticular infiltration with retention of quadriceps muscle strength, function, patient satisfaction, and a short hospital stay. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.