Modular Dual Mobility Constructs Used for Recurrent Hip Instability.

Background Recurrent hip dislocation despite prior attempts at surgical stabilization is a dreadful and technically challenging complication. A modular dual mobility (MDM) articulation has shown promise in addressing this problem, which might seem intractable. Our purpose was to examine the outcomes of revision total hip arthroplasty (THA) with an MDM placed through a direct anterior (DA) approach when all other conservative and surgical treatments have failed. Methods Fifteen patients revised with an MDM for recurrent instability (RI) between 2012 and 2018 by a single surgeon at a single institution were reviewed retrospectively, with a minimum of two years' follow-up. All patients underwent full acetabular revision with an MDM articulation through a DA approach with intraoperative fluoroscopy. No stems were revised. Dislocations, complications, and clinical outcomes are reported. Results  All patients had recurrent posterior instability with a mean number of 4 ± 2 (range: 2 to 8) dislocations prior to MDM revision THA (MDM rTHA). Eight patients had already failed surgical intervention for instability, and seven had failed repeated closed reductions and conservative care. After MDM rTHA, there were no dislocations at a mean follow-up of 4 ± 1 years (range: 2 to 8). Similarly, there were no further revisions or reoperations. Postoperatively, the mean cup inclination improved to 45 ± 2 degrees (range: 41 to 48), and the mean anteversion improved to 20 ± 2 degrees (range: 17 to 23). All cups were well-positioned utilizing fluoroscopic guidance. The mean effective head size increased from 32 mm to 44 mm. The mean hip disability and osteoarthritis disability score (HOOS, Jr) was 73 ± 25% (range: 40 to 100). Conclusion Refractory hip instability in THA may be effectively managed with an MDM articulation, even when prior attempts at surgical stabilization have failed. Intraoperative imaging and a direct anterior approach may aid the challenges of implant positioning and achieving hip stability in a revision setting.

Returning to Yoga Practice and Teaching After Total Hip Arthroplasty.

Patients who practice yoga are motivated to return to practice after total hip arthroplasty (THA). With case reports of dislocations during yoga, the safety of such a return is unclear. The purpose of this study is to examine the timing and feasibility of a return in a subset of highly experienced and motivated patients. Between 2010 and 2019, a total of 19 THA's performed in 14 patients who self-identified as yoga instructors were retrospectively reviewed. Patients who practiced yoga but were not teachers were excluded from this series. The primary outcome measures were the ability to return to yoga, to resume teaching, and fluency with 14 classic poses. Secondary outcomes measured were patient-reported Hip Disability and Osteoarthritis Outcome Score (HOOS, Jr.), complications, and radiographic position of the implants. After surgery, all patients returned to practicing and teaching yoga, and the mean time to each was 2 months. All patients were able to perform all 14 classic poses. At a mean follow-up of 5 years (SD ± 4), there were no complications, and the mean HOOS, JR score was 92 points (SD ± 15). This study demonstrates that a return to yoga in an experienced population is not only possible but also safe after a direct anterior THA. Limitations in performing the poses should be understood, and appropriate modifications should be incorporated when needed.

Aseptic Loosening of Smaller Corail Stems in Heavy, Active Males: A Report of Three Cases.

Recent concerns have been raised regarding a higher failure rate with smaller size Corail stems. This case series examines early aseptic loosening with smaller stems in three large male patients with Dorr A bone. Each stem was fluoroscopically aligned and sized until stable with axial and rotational stress. In each case, failure occurred within six months due to symptomatic metaphyseal debonding. Careful analysis suggests a correlation of failure to small size stems that are comparatively 1) undersized relative to the metaphysis, 2) undersized relative to patient body mass index, and 3) undersized relative to the amount of offset created.

Managing Protrusio Acetabuli With a Direct Anterior Approach Total Hip Replacement.

Introduction The deformities of protrusio acetabuli (PA) present unique reconstructive challenges. An incarcerated femoral head, medialized center of rotation, deficient bone stock, and associated leg length discrepancy add significant technical complexity to total hip arthroplasty (THA). Methods We retrospectively reviewed 23 THAs in 21 patients with PA who underwent direct anterior (DA) approach THA with intraoperative fluoroscopy. All acetabular defects were reconstructed with morcellized femoral head autograft using Bone Mill (Stryker Corporation, Kalamazoo, MI). Results The mean AK distance preoperatively was 8 mm (range: 1-16). Postoperatively, the degree of protrusio improved in all cases, and the mean AK distance decreased to 0 mm. All bone grafts consolidated, and no cups loosened or were revised at a mean of 5.3 years of follow-up. The mean Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) at follow-up was 91. Conclusions These data suggest that the DA approach with intraoperative fluoroscopy may be a reasonable technique in the surgical management of this challenging population.

Surgical Management of Iliopsoas Impingement With Combined Acetabular Revision and Partial Psoas Tenotomy.

Background Persistent groin pain after total hip arthroplasty (THA) can result from iliopsoas impingement (IPI) on the acetabular rim. Controversy exists over the risks and benefits of tenotomy versus revision as a surgical solution. We report our limited experience with combined acetabular revision and partial iliopsoas tenotomy when other conservative treatments have failed. Methodology A total of eight patients revised for IPI by a single surgeon at a single institution were retrospectively reviewed after a minimum one-year follow-up. Preoperatively, all patients had prolonged groin pain for a mean of two years (range: 1-4 years) and had failed conservative treatment for at least six months. All patients underwent acetabular revision through a direct anterior approach (DAA) with partial psoas tendon release. No stems were revised. Dislocations, complications, and clinical outcomes are reported in this study. Results Of the eight patients, seven had a positive diagnostic challenge with an image-guided injection. All revised cups showed radiographic evidence of IPI with relative acetabular retroversion by either a cross-table lateral film or computed tomography scan. Preoperatively, the mean cup anteversion was 4 degrees (range: 0-9 degrees). Postoperatively, the mean cup anteversion was 19 degrees (range: 16-21 degrees). All cups were within the so-called safe zone. To avoid overstuffing, the mean cup size remained unchanged. There were no major postoperative complications. At a mean time to follow-up of 3.3 years, the mean Hip disability and Osteoarthritis Outcome Score for Joint Replacement was 75 points (range: 32-100 points). Conclusion IPI may be effectively managed with combined acetabular revision and tenotomy. The challenges of implant placement and positioning may be aided with intraoperative imaging through a DAA THA.

Do bicortical diaphyseal array pins create the risk of periprosthetic fracture in robotic-assisted knee arthroplasties?

BACKGROUND: Optical array placement for robotic-assisted knee replacement introduces the rare, but real risk of periprosthetic fracture. The purpose of this retrospective study was to review the incidence of fracture with the conventional technique of bicortical diaphyseal pin placement. We also evaluated a modified method of unicortical periarticular pin placement to mitigate this risk. METHODS: We reviewed 2603 knee arthroplasties that were performed between June 2017 and December 2019. The conventional bicortical diaphyseal technique was used in 1571 knees (bicortical diaphyseal group) and the unicortical periarticular technique was used in 1032 knees (unicortical periarticular group). RESULTS: A more than 1-year follow-up revealed that 3 femoral shaft fractures (0.19%) occurred in the bicortical diaphyseal group and no fracture took place in the unicortical periarticular group. There was no array loosening in either group. CONCLUSIONS: The modified unicortical periarticular pin placement is a reliable technique for computer-navigated and robotic-assisted knee arthroplasties. It may be associated with a lower incidence of postoperative femoral shaft fractures, compared to conventional bicortical diaphyseal pinning.

Salvage of Failed Femoral Neck Fracture Fixation with Conversion Total Hip Arthroplasty Using the Direct Anterior Approach.

PURPOSE: Failed femoral neck fracture (FNF) fixation with in situ pinning presents a surgical challenge. Osteoporotic bone, retained hardware, and a typically elderly population magnify the risks of surgery. Here, outcomes of conversion total hip arthroplasty (THA) using two separate incisions in these high-risk patients were examined. MATERIALS AND METHODS: Medical records for 42 patients with a prior history of FNF fixation who underwent conversion THA with hardware removal between 2009 and 2019 were retrospectively reviewed. Surgery was performed by a single surgeon at a single institution. All patients underwent hardware removal followed by direct anterior approach (DAA) THA using two separate incisions. Clinical outcomes, radiographic findings, and perioperative morbidity and mortality are reported. RESULTS: Clinically, there were no postoperative dislocations, periprosthetic fractures, or infections at follow-up. After a mean follow-up of 4 years, the mean hip disability and osteoarthritis outcome score, junior (HOOS, Jr) was 91. Radiographically, the mean postoperative cup abduction was 44 degrees and the mean cup anteversion was 21 degrees with an improvement in preoperative leg length discrepancy. Perioperative complications included one case of immediate foot drop and two readmissions for medical issues. One patient died one month after conversion THA. CONCLUSION: Salvage of failed FNF treatment may be managed with conversion THA and DAA with a separate incision for hardware removal. Preservation of posterior soft tissues using a DAA and intraoperative fluoroscopy may mitigate well-known complications related to fracture and dislocation. While favorable clinical outcomes are possible, salvage surgery is still not without substantial surgical and medical risks.

Modified Two-Stage Exchange for Periprosthetic Joint Infection in UKA.

Periprosthetic joint infection (PJI) is a rare complication following unicompartmental knee arthroplasty (UKA), and current management guidelines are still evolving. This report presents a novel surgical technique of resection arthroplasty with an articulated hemispacer as part of a 2-stage exchange protocol. A 66-year-old man developed a culture-negative PJI four months after a medial UKA. Rather than conventional full resection arthroplasty, the patient underwent partial resection with preservation of the lateral and patellofemoral compartments to maintain vascularized bone stock. An articulating hemispacer fashioned from the old implants after sterilization was reimplanted medially to preserve function during the course of antibiotic treatment. After successful eradication of infection, the patient underwent an uncomplicated conversion total knee replacement facilitated by prior preservation of bone stock. No stems or augments were needed. Therefore, a partial resection arthroplasty with an articulating hemispacer used in a 2-stage exchange protocol may be a reasonable option to eradicate infection and maintain function. In future cases of infected UKA, this technique warrants further consideration and investigation.

Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique.

BACKGROUND: Failure of unicompartmental knee arthroplasty (UKA) is a distressing and technically challenging complication. Conventional conversion techniques (CCT) with rods and jigs have produced varying results. A robotic-assisted conversion technique (RCT) is an unexplored, though possibly advantageous, alternative. We compare our reconstructive outcomes between conventional and robotic methods in the management of failed UKA. METHODS: Thirty-four patients with a failed UKA were retrospectively reviewed. Patients underwent conversion total knee arthroplasty (TKA) with either a CCT or RCT. Seventeen patients were included in each group. All procedures were done by a single surgeon at a single institution, with a mean time to follow-up of 3.6 years (range, 1 to 12). The primary outcome measures were the need for augments and polyethylene thickness. Secondary outcome measures were complications, need for revision, estimated blood loss (EBL), length of stay, and operative time. RESULTS: The mean polyethylene thickness was 12 mm (range, 9 to 15) in the CCT group and 10 mm (range, 9 to 14) in the RCT groups, with no statistical difference between the two groups (P = 0.07). A statistically significant difference, however, was present in the use of augments. In the CCT group, five out of 17 knees required augments, whereas none of the 17 knees in the RCT group required augments (P = 0.04). Procedurally, robotic-assisted surgery progressed uneventfully, even with metal artifact noted on the preoperative computerized tomography (CT) scans. Computer mapping of the residual bone surface after implant removal was a helpful guide in minimizing resection depth. No further revisions or reoperations were performed in either group. CONCLUSIONS: Robotic-assisted conversion TKA is technically feasible and potentially advantageous. In the absence of normal anatomic landmarks to guide conventional methods, the preoperative CT scans were unexpectedly helpful in establishing mechanical alignment and resection depth. In this limited series, RCT does not seem to be inferior to CCT. Further investigation of outcomes is warranted.