# Hevesi 2019 RIP Score Calculator

> Hevesi 2019 RIP Score Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Computes the Recurrent Instability of the Patella (RIP) score per Hevesi 2019 from caller-supplied age, skeletal maturity, trochlear dysplasia status, and TT-TG/PL ratio, returning a total score and risk band.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/rip
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hevesi-2019-rip-score-calculator-e3263038
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SM_F4d8EoHS2CiOyxvl_S

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability hevesi-2019-rip-score-calculator-e3263038
```

Example prompt: Calculate the Hevesi 2019 RIP score for a 22-year-old patient with open physes, trochlear dysplasia present, and a TT-TG/PL ratio of 0.55 — they just had their first patellar dislocation.

## When to prefer this

Use this endpoint when you need to apply the Hevesi 2019 RIP scoring rule specifically — not the Balcarek 2013 rule or other patellar instability prediction models. Ideal for automating orthopedic clinical documentation after a first-time patellar dislocation where the clinician has already assigned trochlear dysplasia grade and measured TT-TG/PL ratio. Note that this endpoint does not interpret imaging; callers must supply all inputs from their own assessment.

## Known failure modes

- Missing required query parameters (age, skeletal_immature, trochlear_dysplasia, tt_tg_pl_ratio) returns a 400 error
- Age outside clamped range 8–80 may be rejected or clamped by the service
- TT-TG/PL ratio outside clamped range 0.1–2.0 may be rejected or clamped
- Non-integer age value returns a validation error
- Incorrect boolean format for skeletal_immature or trochlear_dysplasia causes a parsing error
- Payment failure (x402 protocol) prevents the call from completing

## How this service works

Hevesi 2019 Recurrent Instability of the Patella (RIP) after first-time dislocation. Age <25 scores 2; skeletal immaturity / open physes 1; trochlear dysplasia Dejour A–D (caller-assigned present) 1; TT-TG/PL ratio ≥0.5 scores 1. Max 5. Bands 0–1 low, 2–3 intermediate, 4+ high (10-year recurrent instability 0.0%, 30.6%, 79.2%). Not a surgical order. Not Balcarek 2013 or later PIP models. magent does not read radiographs.

## Output

Returns the Hevesi 2019 RIP total score (integer 0–5), the corresponding risk band (low 0–1, intermediate 2–3, high 4–5), and the published 10-year recurrent instability probability (0.0%, 30.6%, or 79.2%) associated with that band. Does not include imaging interpretation or surgical recommendations.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "age",
      "skeletal_immature",
      "trochlear_dysplasia",
      "tt_tg_pl_ratio"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (integer 8-80; magent clamp, not a published range). Hevesi 2019: age <25 → 2 points; age ≥25 → 0. magent does not assign age."
      },
      "tt_tg_pl_ratio": {
       "type": "number",
       "description": "Caller-assigned tibial tubercle–trochlear groove / patellar length (TT-TG/PL) ratio (Hevesi 2019). ≥0.5 inclusive scores 1. Magent clamp 0.1-2.0, not a published range. magent does not measure TT-TG or patellar length."
      },
      "skeletal_immature": {
       "type": "boolean",
       "description": "Caller-assigned skeletal immaturity / open physes (Hevesi 2019). true scores 1. magent does not read radiographs or assign physeal status. true or false."
      },
      "trochlear_dysplasia": {
       "type": "boolean",
       "description": "Caller-assigned trochlear dysplasia Dejour A–D present (Hevesi 2019). true scores 1. magent does not grade trochlea or read radiographs. true or false."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hevesi-2019-rip-score-calculator-e3263038/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)