Radiographic Accuracy of Malseated Dual-Mobility Liners Varies Based on Implant Design

BACKGROUND

Dual-mobility constructs have gained popularity to mitigate dislocations after high-risk primary and revision total hip arthroplasties. Contemporary data have indicated that malseating of modular dual-mobility liners occurs in up to 6% of cases. The purpose of this cadaveric-based radiographic study was to determine the ability to accurately determine if modular dual-mobility liners were seated.

METHODS

There were 10 hips (5 cadaveric pelvic specimens) used to implant modular dual-mobility liners of 2 designs. One had a liner that seated flush and the other had an extended rim. There were 20 constructs that were well-seated and 20 constructs were intentionally malseated. A comprehensive series of radiographs was reviewed by 2 blinded surgeons. Statistical analyses included Chi-squared testing, logistic regressions, and kappa statistics.

RESULTS

Radiographic assessment of liner malseating was not accurate with an elevated rim design with misdiagnosis in 40% (16 of 40). The flush design had diagnostic errors in 5% (2 of 40; P = .0002). Logistic regressions demonstrated a significantly higher risk of misdiagnosing a malseated liner in the elevated rim group (odds ratio 13). There were 12 of 16 misdiagnoses in the elevated rim group failing to recognize a malseated liner. Each surgeon had almost perfect agreement for intraobserver reliability for flush designs (k 0.90) and fair agreement in the elevated rim design (k 0.35).

CONCLUSION

A comprehensive series of plain radiographs can reliably detect a malseated modular dual-mobility liner with a flush rim design in 95% of cases. However, elevated rim designs are more difficult to accurately identify malseating on plain radiographs.

Collarless Taper Slip and Collared Composite Beam Stems Differ in Failure Modes and Reoperation Rates

BACKGROUND

Cemented femoral components are used in older patients based on lower risk of periprosthetic fracture and implant loosening. This study reports the survivorship free of periprosthetic femoral fracture (PPFX), femoral loosening, all-cause revision, and reoperation between 2 philosophies of cemented stems.

METHODS

In total, 1,306 primary hybrid total hip arthroplasties were performed for osteoarthritis between 2000 and 2018 in a retrospective single center study. Cemented stems included 798 EON composite beam (CB) and 508 Exeter collarless taper slip (CTS) stems. Mean age was 77 years. An inverse treated probability weighted model was utilized to control for risk factors including age, gender, body mass index, year, and surgeon.

RESULTS

There was no difference in risk of PPFX at 10 years (CTS 9% vs CB 5%; hazard ratio [HR] 1.4, P = .47). There was an increased risk of intraoperative fractures requiring fixation in the CB cohort (7/798 [5 calcar, 2 greater trochanter] vs 0/508, P < .001), while there was an increased risk of Vancouver B₂ PPFX in the CTS cohort (7/508 vs 0/798; P < 001). There was a higher risk of femoral loosening in the CB cohort (6/798 vs 0/508; P < .0001). Higher survivorship free of revision (98% vs 91%; HR 4, P = .001) and free of reoperation (96% vs 88%; HR 2.5, P = .002) was seen at 10 years in the CB cohort.

CONCLUSION

The risk of PPFX requiring implant revision was increased in the CTS cohort, while there was an increased risk of femoral component loosening and intraoperative fractures seen in the CB cohort. Surgeons should be aware of the different failure modes when choosing implant design for their patient.

Incidence and Characteristics of Osteolysis in HXLPE THA at 16-Year Follow up in Patients 50 Years and Less

INTRODUCTION

Young patients present a challenge for total hip arthroplasty (THA) survivorship. Highly cross-linked polyethylene (HXLPE) liners have decreased the prevalence of osteolysis; however, concerns exist regarding the biologic activity of wear particles. The purpose of this study was to determine the incidence and characteristics of osteolytic lesions in young HXLPE THA patients at an average 16-year follow up and determine the ability to detect osteolysis.

METHODS

We performed a retrospective study involving 22 patients (26 THA) under age 50 at primary THA receiving HXLPE liners coupled with cobalt-chrome (CoCr) femoral heads. Computed tomography (CT) scans were reviewed for osteolysis. Chi-squared analysis was used for categorical variables and unpaired Kruskal-Wallis rank-sum test for continuous variables. Logistic regression was used to compare wear rates between those patients with and without osteolysis.

RESULTS

The mean age at surgery was 38.5 years. The mean time from surgery to CT scan was sixteen years (range 14.25-19.5 years). Nine of the 26 THA showed osteolysis. The mean volume of the lesions was 2.8 cm3. Linear (mean 0.008 mm/y) and volumetric (mean 4.5 mm3/year) wear rates were negligible. One-third of osteolytic lesions were visible on radiographs. Logistic regression failed to demonstrate a correlation between wear rates or UCLA activity score and osteolysis.

CONCLUSION

We observed osteolysis in 35% of HXLPE THA in young patients at mean 16-year follow up despite zero revisions for wear-related problems and clinically insignificant wear rates.

LEVEL OF EVIDENCE

IV.

Impact of Tourniquet Strategy on Perioperative Results of Modern TKA

Recent changes in perioperative management of total knee patients including tranexamic acid, multimodal pain management, and periarticular injection make previous data on tourniquet use during total knee arthroplasty (TKA) less relevant. The purpose of this study was to evaluate the effect of tourniquet use on short-term postoperative outcomes in the era of modern TKA. Our institutional database was utilized to retrospectively identify three cohorts (long, short, and no tourniquet) of consecutive patients after unilateral TKA with a single surgeon. These three groups were compared using analysis of variance (ANOVA) and post hoc Tukey's tests. Primary endpoints being hemoglobin index (difference in preoperative and postoperative hemoglobin), inpatient narcotic use, surgical time, length of hospital stay (total hours and % day1 discharges), and distance ambulated prior to discharge. The no-tourniquet group used significantly less narcotic than the short-tourniquet (2.4 vs. 2.9 morphine equivalent/hour, p = 0.004) and long-tourniquet groups (2.4 vs. 3.4 morphine equivalents/hour, p < 0.001). The no-tourniquet group ambulated significantly further than patients in the short (108 vs. 57 feet, p < 0.001) and long (108 vs. 76 feet, p < 0.001) groups. Finally, the no-tourniquet group had significantly shorter duration of hospitalization than the long-tourniquet group in both hours in the hospital (35 vs. 57 hours, p < 0.001) and % postoperative day 1 discharge (57 vs. 12%, p < 0.001). TKA without the use of a tourniquet is associated with less narcotic consumption and increased distance ambulated prior to discharge compared with cohorts of patients utilizing tourniquet for a short or long duration.

Effect of Adductor Canal Block on Acute Perioperative Pain and Function in Total Knee Arthroplasty

BACKGROUND

Multimodal pain management strategies are commonplace in perioperative management of total knee arthroplasty (TKA), although controversy remains regarding the role of adductor canal blocks (ACB) in this algorithm. The purpose of this study is to independently evaluate the effect of ACB on short-term postoperative outcomes including (1) length of stay (LOS), (2) postoperative narcotic utilization, and (3) function with physical therapy in the era of modern TKA.

METHODS

We retrospectively identified a cohort of consecutive patients from January 2014 to January 2018 who had undergone unilateral primary TKA using a single-shot ACB in addition to a standardized multimodal pain regimen vs those who only received a multimodal pain regimen. These 2 groups were compared using independent sample t-tests with primary end points of interest being LOS, distance ambulated with therapy, and inpatient narcotic use.

RESULTS

There were 624 patients in the ACB group, with a mean age of 64.5 years. The group without ACB consisted of 69 patients, with a mean age of 67.2 years. We observed no significant difference in narcotic utilization postoperatively (2.361 vs 2.097, P = .088). The ACB group ambulated significantly further with therapy (75.8 vs 59.9 ft, P = .008) and had a shorter LOS in both total hours and percentage of postoperative day 1 (%POD1) discharges (34.8 vs 40.6 hours, P = .01, 83% vs 66.6%, P = .01).

CONCLUSION

ACB did not decrease postoperative pain medication utilization. The modest improvement in distance ambulated with therapy on POD1 (16 ft) and LOS (16% greater POD1 discharges) may not support the cost-effectiveness of this intervention.

LEVEL OF EVIDENCE

III, Retrospective Cohort.

Fifteen-Year Results of Total Hip Arthroplasty With Cobalt-Chromium Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years and Less

BACKGROUND

Highly cross-linked polyethylene (HXLPE) is the most commonly used bearing surface in total hip arthroplasty (THA) because of its superior wear properties, but long-term results in young patients are limited. Mid-term survivorship has been promising; however, polyethylene wear rates and need for revision surgeries remain a concern in this population. The purpose of our study is to investigate polyethylene wear rates, implant survivorship, wear-related revisions, and patient-reported outcomes in a young patient cohort at 15-year follow-up.

METHODS

We performed a retrospective study of a prospective longitudinal cohort of 82 consecutive patients (89 hips) who underwent primary THA with an HXLPE acetabular liner and a cobalt-chromium femoral head. The mean age at the time of surgery for the cohort was 38.8 years (range 12-50). All patients received HXLPE liners with a cementless acetabular component coupled with a cobalt-chrome femoral head through a posterior approach with a cementless femoral component. All components were from a single manufacturer. We recorded University of California, Los Angeles Activity, and modified Harris Hip Scores. Wear calculations were made using the Martell Hip Analysis Suite (Version 8.0.4.3).

RESULTS

At average 15 years (range 13.1-18.5), there was a revision-free survivorship of 97.8% in our HXLPE group with no wear-related revisions. We observed a linear wear rate of 0.0185 mm/y (standard deviation 0.05) after accounting for a 1-year bedding-in period. The volumetric wear rate was found to be 12.80 mm³/y (standard deviation 22.69). These numbers are registered as clinically undetectable and are comparable to steady state wear rates in the same cohort of patients at earlier time points. We found no radiographic changes concerning osteolysis. We observed excellent patient-reported outcomes at this time point with improvements in modified Harris Hip Scores (35.3 [22.5], P < .0001) and University of California, Los Angeles Activity Scores (median 6.0, P < .0001).

CONCLUSION

At 15-year follow-up, we demonstrated that HXLPE bearings in this young cohort had excellent wear properties, maintained superior clinical improvements, and underwent no wear-related revision operations. The HXLPE and cobalt-chrome bearing couple continues to be extremely effective 15 years after primary THA in patients less than 50 years.

LEVEL OF EVIDENCE

IV.

Conventional Polyethylene in Total Hip Arthroplasty in Young Patients: Survivorship, Wear Analysis, and Clinical Outcomes Between 15 and 20 Years

BACKGROUND

Total hip arthroplasty (THA) remains a successful procedure for most patients. However, there is a paucity of information regarding the long-term performance of conventional polyethylene (CPE) bearings in young patients undergoing THA.

METHODS

After accounting for incomplete follow-up of a prospective cohort of 123 THAs in patients ≤50 years, we performed a retrospective review of 101 hips in 84 patients (82.1%) with an average 17.1-year follow-up (14.7-19.6 years). Outcomes of interest included linear and volumetric wear, clinical outcome scores, implant survivorship, and patient mortality. Wear rates were calculated using Martell Software.

RESULTS

Wear analysis revealed median linear and volumetric wear rates of 0.106 mm/y (confidence interval, 0.079-0.133) and 43.58 mm³/y (confidence interval, 33.4-53.75). The modified Harris hip scores improved by 36 points while University of California, Los Angeles activity scores improved by 2.0 points at 15-year follow-up (P < .0001). Twenty-two hips (21.8%) were revised, 13 of which (12.8%) were for wear-related causes at an average of 14.9 years (range, 9.2-21 years) from index arthroplasty. There was significantly higher mortality in patients with a preoperative diagnosis of inflammatory avascular necrosis (P = .015).

CONCLUSION

Because CPE was commonly used in THA over the last 25 years, it is important to understand its implications on the growing revision burden. Significant concerns exist with regard to the long-term durability of CPE bearings in young, moderately active patients 15 years after THA. These patients should be followed closely for wear-related problems. Our results should be used as a comparison when evaluating the outcomes of more modern bearing surface combinations.

Clinical Management of Osteoporotic Fractures

PURPOSE OF REVIEW

This review examines recent literature regarding the clinical management of fragility fractures, provides insight into new practice patterns, and discusses controversies in current management.

RECENT FINDINGS

There are declining rates of osteoporosis management following initial fragility fracture. Management of osteoporotic fractures via a multidisciplinary team reduces secondary fracture incidence and improves overall osteoporotic care. Anabolic agents (abaloparatide and teriparatide) are effective adjuvants to fracture repair, and have shown positive results in cases of re-fracture in spite of medical management (i.e., bisphosphonates). For AO 31-A1 and A2 intertrochanteric hip fractures (non-reverse obliquity), no clinical advantage of intramedullary fixation over the sliding hip screw (SHS) has been proven; SHS is more cost-effective. As fragility fracture incidence continues to rise, orthopedic surgeons must play a more central role in the care of osteoporotic patients. Initiation of pharmacologic intervention is key to preventing subsequent fragility fractures, and may play a supportive role in initial fracture healing. While the media bombards patients with complications of medical therapy (atypical femur fractures, osteonecrosis of jaw, myocardial infarction), providers need to understand and communicate the low incidence of these complications compared with consequences of not initiating medical therapy.

No impact of under-correction and joint line obliquity on clinical outcomes of total knee arthroplasty for the varus knee

PURPOSE

It has been hypothesized that under-correction of a preoperative varus deformity may be more natural and improve outcomes after total knee arthroplasty (TKA). This study's purpose was to assess the impact of hip-knee-ankle (HKA) alignment and joint line obliquity on TKA outcomes for the varus knee.

METHODS

All patients with a preoperative varus deformity received both preoperative and postoperative standing, full-length radiographs from which two independent observers performed radiographic measurements including the HKA axis and mechanical medial proximal tibial angle (mMPTA). Patients were categorized based on their HKA into neutral (0° ± 3°), mild varus (-6° to -3°), severe varus (≤ -6°), and valgus (>3°) cohorts, and separately categorized based on their mMPTA into neutral (90° ± 2°), mild varus (86°-88°), severe varus (<86°), and valgus (>92°) cohorts.

RESULTS

Two hundred and fifty-six patients (mean age 63.8 ± 9.0 years, BMI 33.0 ± 6.2 kg/m², follow-up 1.3 ± 0.6 years) were included. There was no difference in the postoperative SF-12 physical component, mental component, Oxford knee, Forgotten Joint Score, or incremental improvement in scores based on the postoperative alignment category for either the HKA or mMPTA. There was no correlation between the magnitude of change in HKA (r = 0.03-0.1) and mMPTA (r = 0.02-0.1) from preoperatively to postoperatively with clinical outcomes.

CONCLUSIONS

In patients undergoing TKA for a preoperative varus deformity, a specific postoperative HKA or mMPTA alignment category was not associated with improved outcomes. Therefore, categorization of optimal postoperative alignment after TKA may not be possible as static, coronal alignment is just one of many variables that can impact clinical outcomes. Future investigations focusing on the combination of static images with dynamic examinations and ligamentous balancing may shed further insight into the controversy and importance of coronal alignment following TKA.

LEVEL OF EVIDENCE

III.

Perioperative and Early Postoperative Comparison of a Modern Cemented and Cementless Total Knee Arthroplasty of the Same Design

BACKGROUND

Cementless total knee arthroplasty (TKA) designs that incorporate a highly porous, titanium surface have the potential to achieve biologic fixation and improve component survivorship. This study's purpose was to compare perioperative and early postoperative outcomes of a cemented vs cementless TKA of the same design.

METHODS

This was a retrospective review of a consecutive series of TKAs performed at a single institution using a cemented or cementless TKA of the same design (Triathlon, Stryker Inc, Mahwah, NJ). All patients with a minimum of 1-year clinical and radiographic follow-up were reviewed, with 1:1 matching performed for age, gender, body mass index, and preoperative Oxford Knee Score. Chi-square or independent student t tests were used for statistical analyses.

RESULTS

Overall, 62 cemented and 66 cementless TKAs were reviewed, with secondary analyses performed after 1:1 matching of 38 patients in each cohort. In both overall and secondary 1:1 matching analyses, there was no difference in baseline demographics (P = .6-.9). Total operative times were decreased in the cementless cohort (P = .03), but there was no difference in the estimated blood loss or change in hemoglobin levels (P = .2-.7). At a mean of 1.4 ± .5 years postoperatively, patients in both cohorts demonstrated similar improvements in Oxford Knee Scores and satisfaction scores (P = .2-.8), with no patients requiring a revision surgical procedure.

CONCLUSION

A recently introduced cementless TKA design demonstrates excellent perioperative and early postoperative results without failures. Continued surveillance is necessary to elucidate the survivorship and potential long-term benefits of this cementless design.

Is the Direct Superior, Iliotibial Band-Sparing Approach Associated With Decreased Pain After Total Hip Arthroplasty?

BACKGROUND

Recently, the direct superior approach (DSA) has been introduced in total hip arthroplasty (THA) with the goal of limiting soft tissue dissection. This study's purpose was to use a visual pain diagram questionnaire to determine the location and severity of pain in patients undergoing THA via a DSA vs miniposterior approach (MPA).

METHODS

This was a prospective, Institutional Review Board (IRB)-approved investigation from 3 centers. Patients aged 18-70 years with a diagnosis of osteoarthritis were included. Two centers used the MPA, while 1 center the DSA. The DSA uses a 9- to 12-cm incision with its distal extent at the posterosuperior greater trochanter. Dissection into the iliotibial band is avoided, and the capsule at the inferior femoral neck is preserved. All THAs in both cohorts received a cementless, titanium, proximally coated femoral stem and a hemispherical acetabular component.

RESULTS

A total of 42 DSA and 196 MPA THA patients were included. Overall, 43% of patients reported pain in at least 1 of the 8 anatomic areas assessed. There was no difference in the incidence of moderate to severe pain in any anatomic area of interest between the MPA and DSA cohorts (P = .1-.9). Specifically, the incidence of moderate to severe trochanter (17% MPA vs 17% DSA, P = .9), anterior thigh (15% MPA vs 17% DSA, P = .9), and lateral thigh pain (12% MPA vs 12% DSA, P = .9) was nearly identical in both cohorts.

CONCLUSION

This study was unable to demonstrate a difference in the incidence of residual pain after use of a DSA or an MPA approach after THA.

Injuries to the glenoid labrum, including slap lesions

The glenoid labrum of the shoulder has extensive anatomic variation but appears to be important for contributing to shoulder stability and for increasing the depth of contact between the glenoid labrum and the humeral head. Tears of the labrum are commonly seen in association with other pathologic entities, such as instability and rotator cuff tears, and treatment of the labral pathology may be incidental to treatment of the other more significant pathology. However, conditions isolated to the labrum do occur and can be a significant source of shoulder problems. Effective treatment of these lesions may result in significant improvement in the patient's symptoms. Labral lesions are difficult to diagnose, and special diagnostic studies and, frequently, arthroscopy are required. The recently described SLAP lesion is an uncommon but significant cause of shoulder disability that generally requires arthroscopic diagnosis. The arthroscopic treatment of this lesion depends on the type of SLAP lesion present. Recent techniques have permitted arthroscopic stabilization of the biceps labral detachment and type II SLAP lesions.

Chylothorax after posterior spinal instrumentation and fusion

Chylothorax occurred in a 16-year-old girl after posterior spinal fusion and instrumentation for idiopathic scoliosis. Nonoperative management, including chest tube drainage for 26 days and total parenteral nutrition, successfully treated this unusual complication after a posterior spinal fusion.