Oxidized Zirconium Versus Cobalt Chromium for Primary TKA: No Difference in Midterm Revision Rates From the American Joint Replacement Registry.

BACKGROUND: Cobalt chromium (CoCr) is the most commonly used material in TKA; however, the use of oxidized zirconium (OxZr) implants has increased. The advantages to this material demonstrated in basic science studies have not been borne out in clinical studies to date. QUESTION/PURPOSE: In the setting of the American Joint Replacement Registry (AJRR), how do revision rates differ between CoCr and OxZr after primary TKA? METHODS: The AJRR was accessed for all primary TKAs performed between 2012 and 2020 for osteoarthritis, resulting in 441,605 procedures (68,506 with OxZr and 373,099 with CoCr). The AJRR is the largest joint replacement registry worldwide and collects procedure-specific details, making it ideal for large-scale comparisons of implant materials in the United States. Competing risk survival analyses were used to evaluate the all-cause revision rates of primary TKAs, comparing CoCr and OxZr implants. Data from the Centers for Medicare and Medicaid Services claims from 2012 to 2017 were also cross-referenced to capture additional revisions from other institutions. Revision rates were tabulated and subclassified by indication. Multivariate Cox regression was used to account for confounding variables such as age, gender, region, and hospital size. RESULTS: After controlling for confounding variables, there were no differences between the OxZr and CoCr groups in terms of the rate of all-cause revision at a mean follow-up of 46 ± 23 months and 44 ± 24 months for CoCr and OxZr implants, respectively (hazard ratio 1.055 [95% confidence interval 0.979 to 1.137]; p = 0.16) The univariate analysis demonstrated increased rates of revisions for pain and instability in the OxZr group (p = 0.003 and p < 0.001, respectively). CONCLUSION: These findings suggest there is no difference in all-cause revision between OxZr and CoCr implants in the short-term to mid-term. However, further long-term in vivo studies are needed to monitor the safety and all-cause revision rate of OxZr implants compared with those of CoCr implants. OxZr implants may be favorable in patients who have sensitivity to metal. Despite similar short-term to mid-term all-cause revision rates to CoCr implants, because of the limitations of this study, definitive recommendations for or against the use of OxZr cannot be made. LEVEL OF EVIDENCE: Level III, therapeutic study.

The Effect of State-Level Prescription Opioid Legislation on Patient Outcomes After Lumbar Tubular Microdecompression.

BACKGROUND: In the United States, a statewide legislation titled the Strengthen Opioid Misuse Prevention (STOP) Act was enacted in 2017 to limit prescription opioid use and reduce dependence. The impact of state legislation curbing opioid prescription on outcomes after spine surgery is unknown. STUDY DESIGN: Case series. METHODS: Data from consecutive patients undergoing lumbar tubular microdecompression for symptomatic lumbar spine stenosis from June 2016 to June 2019 were retrospectively analyzed. Cases between June 2016 and December 2017 represent the group before the STOP act (pre-STOP), while cases between January 2018 and June 2019 represent the group after legislation enactment (post-STOP). Preoperative and postoperative patient functional scores including the EuroQol-Five Dimensions Index, Oswestry Disability Index (ODI), and the visual analog scale (VAS) for back and leg pain were compared between both groups. The meaningful clinically important difference (MCID) was calculated for each score and was compared between both groups as well. RESULTS: A total of 147 patients met inclusion criteria, with 86 in the pre-STOP group and 61 in the post-STOP group. Analysis of postoperative scores demonstrated statistically lower VAS leg pain score averages in the post-STOP group (P < 0.05). Higher trends in achieving MCID among the post-STOP group were observed; however, the differences between both groups were not statistically significant (P > 0.05 for all). Additionally, there were no statistical differences in rates of unplanned pain-related clinic visits and emergency department (ED) visits, as well as no differences in the number of pain-related calls within 90 days after surgery between both groups. CONCLUSION: The enactment of state legislation to curb the prescribing of opioids for postoperative pain did not negatively affect the rate of achieving clinically meaningful outcomes among patients undergoing lumbar tubular microdecompression for spinal stenosis. Additionally, decreasing the amount of opioids prescribed for postoperative pain does not increase the number of unplanned clinic or ED visits due to pain within 90 days after surgery.

Far Lateral Tubular Decompression: A Case Series Studying One and Two Year Outcomes with Predictors of Failure.

Introduction The optimal surgical treatment of isolated lumbar foraminal stenosis has not been defined. Minimally invasive decompression of the foramen from a far lateral tubular decompression (FLTD) approach has been shown to not only have minimal morbidity but also highly variable success rates at short-term follow-up. It is important to quantify improvement and define the demographic and radiographic parameters that predict failure in this promising, minimally invasive surgical technique. This study investigates pain and disability score improvement following FLTD at 12 and 24 months and investigates associations with failure. Methods All patients who underwent lumbar FLTD by a single surgeon at a single institution from September 2015 to January 2018 were included in this prospective case series. Visual analog scale (VAS) for back pain and leg pain and Oswestry Disability Index (ODI) were collected preoperatively and at the 12- and 24- month follow-ups. Outcomes between visits were fitted to a linear mixed-effects model. The univariate analysis investigated demographic, radiographic, and operative associations with subsequent open revision. Results A total of 42 patients were included in this study. Back pain (VAS 5.84 to 3.32, p<0.001), leg pain (VAS 7.33 to 2.71, p<0.001), and ODI (48.97 to 28.50, p<0.001) demonstrated significant improvements at the 12-month follow-up. Back pain (VAS 3.71, p=0.004), leg pain (VAS 3.04, p<0.001), and ODI (30.63, p<0.001) improvements were maintained at 24-month follow-up. Four patients (9.5%) required subsequent open revision. Subsequent open revision was associated with prior spine surgery (RR=2.85 (2.07-3.63), p=0.045) and scoliosis ≥10° (RR=6.33 (4.87-7.80), p=0.013). Conclusion Back pain, leg pain, and ODI showed significant improvement postoperatively. Improvement is maintained at two years. Prior spine surgery and scoliosis ≥ 10° may be relative contraindications to FLTD.

Unilateral Laminotomy with Bilateral Decompression: A Case Series Studying One- and Two-Year Outcomes with Predictors of Minimal Clinical Improvement.

OBJECTIVE: To assess factors that may predict failure to improve at 12 and 24 months after unilateral laminotomy with bilateral decompression (ULBD) for the management of lumbar spinal stenosis. METHODS: A database of 255 patients who underwent microdecompression surgery by a single orthopedic spine surgeon between 2014 and 2018 was queried. Patients who underwent primary single-level ULBD of the lumbar spine were included. Visual analog scale (VAS) for back pain and leg pain and Oswestry Disability Index (ODI) results were collected preoperatively and at 12 and 24 months postoperatively. Demographic, radiographic, and operative factors were assessed for associations with failure to improve. Clinically important improvement was defined as reaching or surpassing the previously established minimum clinically important difference for ODI (12.8) and not requiring revision. RESULTS: A total of 68 patients were included. Compared with preoperative values for back pain, leg pain, and ODI (7.32, 7.53, and 51.22, respectively), there were significant improvements on follow-up at 12 months (2.89, 2.23, and 22.40, respectively; P < 0.001) and 24 months (2.80, 2.11, 20.32, respectively; P < 0.001). Based on the defined criteria, 50 patients showed clinically important improvement after ULBD. Of the 18 patients who failed to improve, 12 required revision. Independent predictors of failure to improve included female sex (adjusted odds ratio, 5.06; 95% confidence interval, 1.49-21.12; P = 0.014) and current smoker status (adjusted odds ratio, 5.39; 95% confidence interval, 1.39-23.97; P = 0.018). CONCLUSIONS: ULBD for the management of lumbar spinal stenosis leads to clinically important improvement that is maintained over a 24-month follow-up period. Female sex and tobacco smoking are associated with poorer outcomes.

Alternative technique for knee manipulation under anesthesia.

Total knee arthroplasty is a successful surgery for the majority of patients with osteoarthrosis of the knee. Approximately 5% of patients undergoing total knee arthroplasty experience loss of motion or arthrofibrosis. Manipulation under anesthesia (MUA) is generally indicated for patients who do not achieve >90° of flexion by 6-12 weeks postoperatively. Complications from MUA are rare but can be devastating. We describe a novel technique for MUA with no reported major complications in our review of 78 patients. The average flexion improved from 80.0 (±3.8) before manipulation to 115.4 (±2.1) after manipulation. There were no major complications including fracture or extensor mechanism injury.

Is There a Deficit After Nonoperative Versus Operative Treatment of Shortened Midshaft Clavicular Fractures in Adolescents?

BACKGROUND: Recent clinical studies in adults have reported a higher incidence of symptomatic malunions and functional deficits in nonoperatively treated shortened midshaft clavicular fractures. We sought to determine whether functional or subjective deficits are found in adolescents after operative versus nonoperative treatment of clavicle fractures. METHODS: Adolescents with displaced midshaft clavicle fractures, >15 mm of shortening, and a minimum of 9 months of follow-up were recruited. Exclusion criteria included concomitant upper extremity injuries or abnormalities that would affect biomechanical strength testing. Sixteen patients, equally divided between nonoperative and operative plate fixation, met inclusion criteria and consented to testing. The average age (±SD) at the time of injury was 14±2 years (range, 10 to 16 y), time from injury was 22±10 months (range, 10 to 41 mo), and shortening was 24±6 mm (range, 16 to 35 mm). Consenting subjects completed a QuickDASH Score, Constant Shoulder Score, and questions regarding satisfaction with treatment. Quantitative isometric strength, range of motion, and abduction fatigue testing was performed on the involved and uninvolved sides for comparison. RESULTS: Treatment groups did not differ in age, time from injury, or fracture shortening. QuickDASH and Constant Shoulder Scores were perfect in all but 1 patient in the operative group who actively complained of persistent symptomatic hardware. This patient and one other in the operative group underwent symptomatic hardware removal. There were no cases of symptomatic malunions in the nonoperative group. All patients expressed satisfaction with their treatment. Two in each treatment group were unsatisfied with the appearance of the clavicle. With the exception of a 3% decrease in abduction strength in the operative group (P=0.03) there were no differences in range of motion, isometric strength, or abduction fatigue of the involved shoulder in either treatment group. CONCLUSIONS: Shortened midshaft clavicular fractures had excellent outcomes after both operative and nonoperative treatments. No subjective or objective differences were observed between treatment groups. LEVEL OF EVIDENCE: Level III-therapeutic, retrospective comparative study.

Accuracy of Pedicle Screw Placement in Children 10 Years or Younger Using Navigation and Intraoperative CT.

STUDY DESIGN: A consecutive case series. OBJECTIVE: To determine the revision rate for pedicle screws placed using intraoperative CT and image-guided navigation in children 10 years or younger. SUMMARY OF BACKGROUND DATA: Screws are frequently used for spinal instrumentation in young children, although this is only by physician-directed use. This is a multicenter retrospective study of patients aged 10 years or younger, who underwent spinal screw instrumentation with image-guided navigation. We hypothesized that intraoperative navigation would result in a high rate of accuracy for screw placement. METHODS: Between 2007 and 2013, 130 pedicle and 7 lateral mass screws were placed in 16 consecutive patients undergoing a total of 17 surgeries at 2 institutions. Mean age at surgery was 6.9 years (range, 0.8-10.9 y). Screws were placed using an open technique with intraoperative CT (O-arm) and image-guided navigation (Stealth). Procedures included: growing spine device (3), hemivertebrae excision (4), posterior fusion (7), cervical fusion (2), and vertebral column resection (1). Congenital deformity was the most common diagnosis. Primary outcome measures were need for intraoperative screw revision or complication associated with screw placement. RESULTS: Mean number of screws used per procedure was 8.1 (range, 2-17). Screws were placed from C1 to L5. Of the 137 screws, 3 required revision to shorter screws for an overall accuracy rate of 97.8%. In 1 case, a right T3 screw was revised due to anterior penetration. In another case, left-sided T1 and T2 pedicle screws were shortened 5 mm because they had penetrated the anterior aspect of their respective vertebral bodies. There were no screw-related complications. CONCLUSIONS: In this series, image-guided navigation resulted in accurate placement of screws in patients aged 10 years or younger with no associated intraoperative complications. The navigated accuracy rate (97.8%) is significantly higher (P=0.01) than the reported 90.9% pedicle screw accuracy rate without navigation in the same age group by Baghdadi and colleagues. Intraoperative CT and image guidance were useful in our practice for placement of screws in skeletally immature patients.

Short-courses of dexamethasone abolish bisphosphonate-induced reductions in bone toughness.

Atypical femoral fractures, which display characteristics of brittle material failure, have been associated with potent remodeling suppression drugs. Given the millions of individuals treated with this class of drugs it is likely that other factors play a role in these fractures. Some evidence suggests that concomitant use of corticosteroids may contribute to the pathogenesis although data in this area is lacking. The goal of this study was to assess the combined role of bisphosphonates and dexamethasone on bone mechanical properties. Skeletally mature beagle dogs were either untreated controls, or treated with zoledronic acid (ZOL), dexamethasone (DEX), or ZOL + DEX. Zoledronic acid (0.06 mg/kg) was given monthly via IV infusion for 9 months. DEX (5 mg) was administered daily for one week during each of the last three months of the 9 month experiment. Ribs were harvested and assessed for bone geometry, mechanical properties, and remodeling rate (n = 3-6 specimens per group). DEX significantly suppressed intracortical remodeling compared to vehicle controls while both ZOL and the combination of DEX + ZOL nearly abolished intracortical remodeling. ZOL treatment resulted in significantly lower bone toughness, determined from 3-point bending tests, compared to all other treatment groups while the toughness in ZOL + DEX animals was identical to those of untreated controls. These findings suggest that short-courses of dexamethasone not only do not adversely affect toughness in the setting of bisphosphonates, but also actually reverse the adverse effects of its treatment. Understanding the mechanism for this tissue-level effect could lead to novel approaches for reducing the risk of atypical femoral fractures.