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.

Functional and radiographic outcomes following distal ulna implant arthroplasty

PURPOSE

To determine the outcome of ulnar head endoprostheses in the treatment of distal radioulnar joint instability, arthrosis, or both.

METHODS

We conducted a retrospective review of 47 patients to analyze the outcome of a single ulnar head replacement over a 10-year period. All patients reported pain or instability at the distal radioulnar joint. Standardized assessments included a patient-rated pain score, forearm range of motion, grip strength, and Mayo wrist score. We examined preoperative and postoperative radiographs for final implant position, loosening, and osteolysis.

RESULTS

We observed 47 patients for a median of 56 months (minimum, 16 mo). There was a statistically significant decrease in pain scores from 4.6 to 2.2 and improvement in the mean Mayo wrist score from 14 to 69 points after surgery. There was no significant improvement in forearm rotation and wrist function. Kaplan-Meier analysis demonstrated 83% survival at 6 years. A total of 14 patients (30%) required additional surgical procedures after primary arthroplasty. Risk factors for failure included history of previous surgery, use of an extended collar, lucency greater than 2 mm around the implant stem, and pedestal formation at the tip of the implant.

CONCLUSIONS

Distal ulna implant arthroplasty reduces pain and improves function in patients with distal radioulnar joint instability, arthrosis, or both.