The Double-Cup Construct: A Novel Treatment Strategy for the Management of Paprosky IIIA and IIIB Acetabular Defects.

BACKGROUND: Treatment of massive acetabular bone loss in revision total hip arthroplasty is complex, and various treatment strategies have been described. We describe a novel technique of using a Trabecular Metal Revision Shell as a buttress augment creating a "double-cup" construct rather than the use of custom triflanges or cup-cage constructs for Paprosky types IIIA and IIIB acetabular defects. METHODS: We retrospectively reviewed 20 double-cup cases at a mean of 2.4 years follow-up at a single institution between 2005 and 2014. We evaluated postoperative radiographic evidence of acetabular loosening and complication rates, restoration of hip center of rotation, preoperative and postoperative modified Harris Hip Score, and Merle d'Aubigne-Postel pain and walking scores. RESULTS: There were no revisions for acetabular loosening and no cases of aseptic loosening. We observed a 25% dislocation rate, which was the most common complication. Most dislocations occurred within the first year after surgery and most were acetabulum only revisions. Hip center of rotation was restored to an average of 22.5 mm within the interteardrop line. Average Harris Hip Score improved from 28.2 to 68.7 (P < .001) and Merle d'Aubigne-Postel pain and walking scores improved from 2.7 to 5.1 and 2.4 to 4, respectively (P < .001). CONCLUSION: The double-cup construct is a reliable option for reconstruction of Paprosky type IIIA and IIIB acetabular defects with no cases of acetabular loosening both clinically and radiographically at a mean of 2 years follow-up. The most common complication was dislocation in the acetabulum-only revisions, and clinical outcome measures were reliably improved in surviving cases.

The Evolution of Implant Design Decreases the Incidence of Lateral Release in Primary Total Knee Arthroplasty.

BACKGROUND: Appropriate balancing of the patellofemoral joint (PFJ) using a lateral release can help to prevent patellar instability in total knee arthroplasty (TKA). Contemporary total knee implant designs are characterized by enhanced trochlear geometry more similar to native knee anatomy to minimize instability and reduce utilization of a lateral release. METHODS: We retrospectively reviewed consecutive TKA cases from a single senior surgeon's practice with 3 successive total knee designs: the Press-Fit Condylar (PFC), the Sigma, and the ATTUNE (DePuy, Warsaw, IN). We evaluated the use of lateral release with each implant type to determine if design changes have improved patellar stability, reducing the need for lateral release. We used multivariate analysis to determine the association between implant type and lateral release, adjusting for age, sex, preoperative alignment, and bearing type. RESULTS: We evaluated 1991 records of primary TKAs performed from 1980-2015. As compared with the ATTUNE, the adjusted odds of lateral release were greater for patients receiving PFC implants (Odds ratio [OR] 6.35, 95% confidence interval [CI] 3.85,10.49) and Sigma implants (OR 2.02, 95% CI 1.26, 3.23). In addition, fixed bearing implants were associated with greater adjusted odds of lateral release (OR 1.80, 95% CI 1.24, 2.62). CONCLUSION: We found that older knee implants were associated with higher use of lateral release, with successive designs the need for lateral release to balance the PFJ decreased. Continued design improvements to match the native knee anatomy may further improve the stability of the PFJ in future designs.

Catastrophic Head-Neck Dissociation of a Modular Cementless Femoral Component.

CASE: We report two cases of modular head-neck junction failure involving the Stryker Accolade TMZF stem leading to sudden dissociation of the femoral head from the stem. Both patients presented with mechanical symptoms in the hip followed by pain and hip dysfunction. Disassembly of the head and deformation of the male taper were seen on preoperative radiographs. Intraoperatively, both patients had substantial metallosis with a markedly damaged taper requiring stem revision. CONCLUSION: We recommend regular clinical and radiographic surveillance of patients with the Stryker Accolade TMZF stem, especially those patients with pain and/or mechanical symptoms.

Mortality of elderly patients after two-stage reimplantation for total joint infection: a case-control study.

The mortality of two-stage reimplantation for periprosthetic joint infection in patients over the age of 80 has not previously been studied. We retrospectively reviewed 134 elderly patients undergoing two-stage reimplantation at 90 days, 1 year and 5 years and compared them to a matched cohort who underwent single-stage aseptic total joint revision. There was no significant difference in preoperative comorbidities between groups. The mortality rates for the two-stage and aseptic groups were 39.9% and 34.1% respectively with an overall mortality rate of 36.7%. There was no significant difference in mortality at any time point (95% CI: 29.4, 43.1). Two-stage reimplantation does not significantly increase the mortality of patients over the age of 80 when compared to a matched cohort undergoing aseptic revision at our institution.

Clinical outcome of internal fixation of unstable juvenile osteochondritis dissecans lesions of the knee.

Juvenile osteochondritis dissecans (OCD) lesions of the knee are a common cause of knee pain in skeletally immature patients.The authors sought to determine lesion healing rates, the risk factors associated with failure to heal, and the clinical outcomes for patients who underwent internal fixation for unstable OCD lesions. A retrospective review was conducted of all patients who underwent internal fixation of OCD lesions from 1999 to 2009. Using validated scoring systems, clinical outcome and functional activity were evaluated at the follow-up. The study group comprised 19 patients (20 knees). Mean patient age was 14.5 years (range, 12-17 years). Mean clinical follow-up was 7 years (range, 2-13 years). Mean radiographic follow-up was 2.5 years (range, 0.5-9 years). Fourteen (70%) lesions were grade 3 and 6 (30%) were grade 4. Eleven knees had lateral condyle lesions and 9 had medial lesions. Bioabsorbable fixation was used in 13 knees, metal fixation was used in 5 knees, and 2 knees were fixed with a combination of methods. Osseous integration was evident in 15 (75%) of 20 knees at final follow-up. The 5 unhealed lesions were lateral condylar lesions. Mean Tegner activity scores improved from 3.3 preoperatively to 5.6 at final follow-up. Mean Lysholm and International Knee Documentation Committee scores were 86.8 and 88.7, respectively, at final follow-up. Further operative intervention was required in 11 knees, with 50% of patients undergoing removal of hardware and 15% requiring subsequent osteochondral allograft transplantation. The authors recommend bioabsorbable fixation for symptomatic stable lesions and metal compression screws with staged removal for unstable lesions.

Navigation-assisted fluoroscopy in minimally invasive direct lateral interbody fusion: a cadaveric study.

BACKGROUND: Minimally invasive surgery (MIS) is dependent on intraoperative fluoroscopic imaging for visualization, which significantly increases exposure to radiation. Navigation-assisted fluoroscopy (NAV) can potentially decrease radiation exposure and improve the operating room environment by reducing the need for real-time fluoroscopy. The direct lateral interbody fusion (DLIF) procedure is a technique for MIS intervertebral lumbar and thoracic interbody fusions. This study assesses the use of navigation for the DLIF procedure in comparison to standard fluoroscopy (FLUORO), as well as the accuracy of the NAV MIS DLIF procedure. METHODS: Three fresh whole-body cadavers underwent multiple DLIF procedures at the T10-L5 levels via either NAV or FLUORO. Radiation exposure and surgical times were recorded and compared between groups. An additional cadaver was used to evaluate the accuracy of the NAV system for the DLIF procedure by measuring the deviation error as the surgeon worked further from the anterior superior iliac spine tracker. RESULTS: Approach, discectomy, and total fluoroscopy times for FLUORO were longer than NAV (P < .05). In contrast, the setup time was longer in NAV (P = .005). Cage insertion and total operating times were similar for both. Radiation exposure to the surgeon for NAV was significantly less than FLUORO (P < .05). Accuracy of the NAV system was within 1 mm for L2-5. CONCLUSION: Navigation for the DLIF procedure is feasible. Accuracy for this procedure over the most common levels (L2-5) is likely sufficient for safe clinical application. Although initial setup times were longer with NAV, simultaneous anteroposterior and lateral imaging with the NAV system resulted in overall surgery times similar to FLUORO. Navigation minimizes fluoroscopic radiation exposure. CLINICAL SIGNIFICANCE: Navigation for the DLIF procedure is accurate and decreases radiation exposure without increasing the overall surgical time.