Better flexion and early recovery with medial-stabilized vs single-radius total knee arthroplasty with kinematic alignment: Two-year clinical results.

BACKGROUND: There are few studies comparing outcomes in patients with posterior cruciate ligament-sacrificing single-radius (SR) versus medial-stabilized (MS) knee devices. Both types of implants are designed to maximize deep-flexion and to maintain stability throughout the knee flexion arc. The aim of this study was to determine whether two-year outcomes differ between these two implant groups. METHODS: Two-hundred and ten patients took part in this retrospective cohort single center study. The SR patients (n = 109) were enrolled in one randomized trial, and the MS knees (n = 101) in another. Patient consent and Investigative Review Board approval was obtained. Radiographs and clinical outcomes were gathered preoperatively and at six weeks, six months, one year and two years. RESULTS: There were no statistically significant differences between treatment groups in terms of preoperative demographic characteristics. The MS group had significantly better knee flexion starting at six months postoperative through two years postoperatively (p < 0.05 - p< 0.001). The Knee Society Pain/Motion score was better in the MS group at one year (95.41 vs 90.86, p < 0.002). The Knee Society Pain score was also better in the MS group starting at six weeks through one year (six weeks: 35.3 vs 30, p = 0.007; one year: 46.4 vs 42.4, p = 0.005, respectively). CONCLUSION: The MS group had better clinical outcomes than the SR group, with significantly greater knee flexion from six months through two years, better Knee Society Pain scores at six weeks through one year, and higher Knee Society Pain/Motion scores at six weeks and one year postoperatively. LEVEL OF EVIDENCE: I.

Increased Risk of Lateral Femoral Cutaneous Nerve Injury in Patients With Previous Hip Arthroscopy Who Underwent a Direct Anterior Approach Total Hip Arthroplasty.

Purpose: To evaluate the rates of lateral femoral cutaneous nerve (LFCN) injury in patients who underwent a direct anterior approach (DAA) total hip arthroplasty (THA) with and without previous hip arthroscopy. Methods: We retrospectively investigated consecutive DAA THAs performed by a single surgeon. These cases were grouped into patients with and without a history of previous ipsilateral hip arthroscopy. LFCN sensation was assessed during the initial follow-up (6 weeks) and 1-year (or most recent) follow-up visits. The incidence and character of LFCN injury was compared between the 2 groups. Results: In total, 166 patients underwent a DAA THA with no previous hip arthroscopy, and 13 had a history of previous arthroscopy. Of the 179 total patients who underwent THA, 77 experienced some form of LFCN injury at initial follow-up (43%). The rate of injury for the cohort with no previous arthroscopy was 39% (n = 65/166) on initial follow-up, whereas the rate of injury for the cohort with a history of previous ipsilateral arthroscopy was 92% (n =12/13) on initial follow-up (P < .001). In addition, although the difference was not significant, 28% (n = 46/166) of the group without history of previous arthroscopy and 69% (n = 9/13) of the group with a history of previous arthroscopy had continued symptoms of LFCN injury at most recent follow-up. Conclusions: In this study, patients who underwent hip arthroscopy before an ipsilateral DAA THA were at increased risk of LFCN injury compared with patients who underwent a DAA THA without a previous hip arthroscopy. At final follow-up of patients with initial LFCN injury, symptoms resolved in 29% (n = 19/65) of patients with no previous hip arthroscopy and 25% (n = 3/12) of patients with previous hip arthroscopy. Level of Evidence: Level III, case-control study.

A prospective comparison of total knee arthroplasty using ultra-congruent, condylar-stabilizing, and posterior-stabilized devices implanted with kinematic alignment: better 2-year outcomes with ultra-congruent.

PURPOSE: This study compared the 5-year results of posterior cruciate ligament (PCL)-sacrificing total knee arthroplasty (TKA) with either a post and cam posterior-stabilized (PS) device, a dished, congruent condylar-stabilizing (CS) device, or a deep-dished ultra-congruent (UC) device. The hypothesis was that the clinical and radiographic outcomes would be equivalent. CS and PS participants were part of a prospective, randomized trial, and UC participants were part of a separate prospective, non-randomized protocol that was otherwise identical. A kinematic alignment surgical technique was utilized. METHODS: Participants were assessed preoperatively, and postoperatively at 6 weeks, 6 months, and annually for 5 years by Knee Society Score (KSS), SF-36 v2, Lower Extremity Activity Scale (LEAS), and physical and radiographic evaluation. There were 116 CS/PS participants and 69 UC participants who participated in the study. RESULTS: Tourniquet (P = .02) and operative (P = .01) times for the CS and UC groups were significantly shorter than the PS group. KSS Function scores were better for the UC group than the CS and PS groups at 6 months (P = .04) and 1 year (P = .03), and better in the UC group vs. CS at 2 years (P = .04). The KSS Pain-only score was also better in the UC compared to PS at 6 months (P = .04). There were no significant differences for the KSS Pain/Motion scores, flexion, SF-36, and LEAS scores at any time. CONCLUSION: These data confirm the hypothesis that there are no clinically meaningful significant differences in outcomes between the three groups at a 5-year minimum follow-up, though there is a trend toward less pain and better function at earlier visits in the UC group. LEVEL OF EVIDENCE: II.

Clinical outcomes and survivorship of cementless triathlon total knee arthroplasties: a systematic review.

BACKGROUND: Over the last decade, cementless total knee arthroplasty has demonstrated improved outcomes and survivorship due to advances in technologies of implant design, manufacturing capabilities, and biomaterials. Due to increasing interest in cementless implant design for TKA, our aim was to perform a systematic review of the literature to evaluate the clinical outcomes and revision rates of the Triathlon Total Knee system over the past decade. METHODS: A systematic review of the literature was conducted following PRISMA guidelines for patients who underwent total knee arthroplasty with cementless Triathalon Total Knee System implants. Patients had a minimum of two-year follow-up and data included clinical outcome scores and survivorship data. RESULTS: Twenty studies were included in the final analysis. The survivability of the Stryker Triathlon TKA due to all causes was 98.7%, with an aseptic survivability of 99.2%. The overall revision incidence per 1,000 person-years was 3.4. Re-revision incidence per 1,000 person-years was 2.2 for infection, and 1.3 for aseptic loosening. The average KSS for pain was 92.2 and the average KSS for function was 82.7. CONCLUSIONS: This systematic review demonstrated excellent clinical outcomes and survivorship at a mean time of 3.8 years. Additional research is necessary to examine the long-term success of the Stryker Triathlon TKA and the use of cementless TKAs in obese and younger populations. LEVEL OF EVIDENCE: III.

A Case Report of a Subdural Hematoma following Spinal Epidural prior to a Total Knee Arthroplasty.

Introduction: This case report adds to current literature on management of a subdural hematoma following total knee arthroplasty and is particularly important as joint replacement moves into outpatient surgery centers where the orthopedic surgery team becomes the sole patient contact point. Case Presentation. A 66-year-old male presented to the emergency department five days after elective robotic-assisted left total knee arthroplasty performed with spinal epidural with the symptoms of a persistent nonpostural headache. CT of the head revealed a small bifrontal acute subdural hematoma. He was admitted for overnight monitoring as a precaution. No vascular abnormalities or underlying pathology was found on further advanced imaging. He was discharged the following morning after follow-up CT showed no focal changes. Magnetic resonance imaging (MRI) one month later confirmed resolution of the subdural hematoma. Conclusion: Orthopedic surgeons should be aware of the signs and symptoms, as well as the risk factors for subdural hematomas following lumbar puncture, as it is a rare, but potentially life-threatening complication of spinal epidural.

Of Mice and Monkeys: Neuroprotective Efficacy of the p38 Inhibitor BIRB 796 Depends on Model Duration in Experimental Glaucoma.

Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). Early progression involves retinal ganglion cell (RGC) axon dysfunction that precedes frank degeneration. Previously we demonstrated that p38 MAPK inhibition abates axonal dysfunction and slows degeneration in the inducible microbead occlusion model of glaucoma in rat. Here, we assessed the neuroprotective effect of topical eye delivery of the p38 MAPK inhibitor BIRB 796 in three models of glaucoma (microbead occlusion in rat and squirrel monkey and the genetic DBA/2 J mouse model) with distinct durations of IOP elevation. While BIRB 796 did not influence IOP, treatment over four weeks in rats prevented degradation of anterograde axonal transport to the superior colliculus and degeneration in the optic nerve. Treatment over months in the chronic DBA/2 J model and in the squirrel monkey model reduced expression and activation of p38 downstream targets in the retina and brain but did not rescue RGC axon transport or degeneration, suggesting the efficacy of BIRB 796 in preventing associated degeneration of the RGC projection depends on the duration of the experimental model. These results emphasize the importance of evaluating potential therapeutic compounds for neuroprotection in multiple models using elongated treatment paradigms for an accurate assessment of efficacy.

Towards A Microbead Occlusion Model of Glaucoma for a Non-Human Primate.

Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). The disease causes vision loss through the degeneration of retinal ganglion cell neurons and their axons in the optic nerve. Using an inducible model of glaucoma, we elevated IOP in the squirrel monkey (Saimiri boliviensis) using intracameral injection of 35 µm polystyrene microbeads and measured common pathogenic outcomes in the optic projection. A 42% elevation in IOP over 28 weeks reduced anterograde transport of fluorescently-labeled cholera toxin beta from retina to the lateral geniculate nucleus (60% decrease), and to the superior colliculus (49% decrease). Pressure also reduced survival of ganglion cellaxons in the optic nerve by 22%. The same elevation caused upregulation of proteins associated with glaucomatous neurodegeneration in the retina and optic nerve, including complement 1q, interleukin 6, and brain-derived neurotrophic factor. That axon degeneration in the nerve lagged deficits in anterograde transport is consistent with progression in rodent models, while the observed protein changes also occur in tissue from human glaucoma patients. Thus, microbead occlusion in a non-human primate with a visual system similar to our own represents an attractive model to investigate neurodegenerative mechanisms and therapeutic interventions for glaucoma.

Oral Delivery of a Synthetic Sterol Reduces Axonopathy and Inflammation in a Rodent Model of Glaucoma.

Glaucoma is a group of optic neuropathies associated with aging and sensitivity to intraocular pressure (IOP). The disease is the leading cause of irreversible blindness worldwide. Early progression in glaucoma involves dysfunction of retinal ganglion cell (RGC) axons, which comprise the optic nerve. Deficits in anterograde transport along RGC axons to central visual structures precede outright degeneration, and preventing these deficits is efficacious at abating subsequent progression. HE3286 is a synthetic sterol derivative that has shown therapeutic promise in models of inflammatory disease and neurodegenerative disease. We examined the efficacy of HE3286 oral delivery in preventing loss of anterograde transport in an inducible model of glaucoma (microbead occlusion). Adult rats received HE3286 (20 or 100 mg/kg) or vehicle daily via oral gavage for 4 weeks. Microbead occlusion elevated IOP ~30% in all treatment groups, and elevation was not affected by HE3286 treatment. In the vehicle group, elevated IOP reduced anterograde axonal transport to the superior colliculus, the most distal site in the optic projection, by 43% (p = 0.003); HE3286 (100 mg/kg) prevented this reduction (p = 0.025). HE3286 increased brain-derived neurotrophic factor (BDNF) in the optic nerve head and retina, while decreasing inflammatory and pathogenic proteins associated with elevated IOP compared to vehicle treatment. Treatment with HE3286 also increased nuclear localization of the transcription factor NFκB in collicular and retinal neurons, but decreased NFκB in glial nuclei in the optic nerve head. Thus, HE3286 may have a neuroprotective influence in glaucoma, as well as other chronic neurodegenerations.

Nanosponge-Mediated Drug Delivery Lowers Intraocular Pressure.

PURPOSE: We examined the efficacy of an extended-release drug delivery system, nanosponge (NS) encapsulated compounds, administered intravitreally to lower intraocular pressure (IOP) in mice. METHODS: Bilateral ocular hypertension was induced in mice by injecting microbeads into the anterior chamber. Hypertensive mice received NS loaded with ocular hypotensive drugs via intravitreal injection and IOP was monitored. Retinal deposition and retinal ganglion cell (RGC) uptake of Neuro-DiO were examined following intravitreal injection of Neuro-DiO-NS using confocal microscopy. RESULTS: Brimonidine-loaded NS lowered IOP 12% to 30% for up to 6 days (P < 0.02), whereas travoprost-NS lowered IOP 19% to 29% for up to 4 days (P < 0.02) compared to saline injection. Three bimatoprost NS were tested: a 400-nm NS and two 700-nm NS with amorphous (A-NS) or amorphous/crystalline (AC-NS) crosslinkers. A single injection of 400 nm NS lowered IOP 24% to 33% for up to 17 days compared to saline, while A-NS and AC-NS lowered IOP 22% to 32% and 18% to 26%, respectively, for up to 32 days (P < 0.046). Over time retinal deposition of Neuro-DiO increased from 19% to 71%; Neuro-DiO released from NS was internalized by RGCs. CONCLUSIONS: A single injection of NS can effectively deliver ocular hypotensive drugs in a linear and continuous manner for up to 32 days. Also, NS may be effective at targeting RGCs, the neurons that degenerate in glaucoma. TRANSLATIONAL RELEVANCE: Patient compliance is a major issue in glaucoma. The use of NS to deliver a controlled, sustained release of therapeutics could drastically reduce the number of patients that progress to vision loss in this disease.

The microbead occlusion model: a paradigm for induced ocular hypertension in rats and mice.

PURPOSE: Elevated intraocular pressure (IOP) is an important risk factor for glaucoma. Animal models often involve techniques for IOP elevation that are surgically invasive. Here the authors describe a novel and relatively simple method for inducing a highly consistent, modest, and repeatable elevation in IOP for rats and mice. METHODS: IOP was elevated unilaterally by injection of polystyrene microbeads into the anterior chamber to occlude aqueous outflow in rats (2.5-7 microL) and mice (1 microL). The fellow eye received an equivalent saline injection as internal control. The authors used tonometry to measure microbead-induced IOP elevations. Optic nerves were processed histologically to determine axon loss. RESULTS: For rats, a single injection of microbeads raised IOP by 21% to 34%, depending on volume, for approximately 2 weeks, though they were not tracked to full recovery. IOP in the saline-injected eye was constant. An additional injection (5 microL) extended the elevation to 8 weeks. Cumulative pressure exposure for both injections increased linearly. For mice, a single 1-microL injection of microbeads elicited a highly regular 30% elevation in IOP that persisted for more than 3 weeks, with a linear rise in cumulative pressure exposure. For both rats and mice, interanimal variability on a given day was modest, approximately 5% of the mean IOP measurement. Extended elevations (4-5 weeks) induced approximately a 20% loss of axons in both rats and mice. CONCLUSIONS: These data support a novel and flexible model of modest ocular hypertension with axon loss. The maximal duration of IOP elevation will be further characterized in future studies.