Bibliographic record
Abstract
Modular necks are a relatively new innovation in total hip arthroplasty (THA), with several companies now offering modular neck options. The proposed advantages of reduced impingement, reduced dislocation rate, and better reconstitution of leg length and offset are compelling. However, few reports in the literature address the outcomes of these devices, and those that are published at best demonstrate equivalence to conventional THA. There are numerous disadvantages to this new technology. Neck dissociation has been reported with a specific design of the modular taper. Numerous case reports exist of the fracture of titanium modular femoral necks, with 1 large series of 5000 cases reporting a fracture rate of 1.4%. Fractures occurred more frequently in heavy men (>100 kg), with the preponderance of fractures occurring around the 2-year mark. Retrieval analysis demonstrates failure of the titanium components at the Morse taper junction of the neck and femoral stem at the point of maximal tension, likely related to notch sensitivity. The additional interface of modular necks in the effective joint space has the potential to generate significant metal ions through a pitting corrosion process. Evidence exists of highly elevated serum cobalt and chromium ions in a modular junction used in large-head THA supporting these concerns. The use of particular neck geometries, such as long retroverted necks, may adversely affect the local biomechanical forces on the femoral component. The proposed mechanism is an increased lever arm leading to increased torque on stair climbing or rising from a chair. Finally, modular necks add significant costs to the implant and the health care system. On balance, based on the literature, the proximal modular neck in THA is a bridge too far.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".