Model note · Prosthetic Limbs
Ottobock C-Leg 4 microprocessor knee
The C-Leg 4 is a microprocessor-controlled hydraulic prosthetic knee for people with transfemoral, knee disarticulation or hip disarticulation amputation, fitted and serviced by prosthetists. Sensors let it adjust stance and swing resistance in real time, including on stairs, ramps and uneven ground, and it signals faults to the user through beeps and vibrations while dropping into a safety mode with fixed resistance when something goes wrong.
The model
Maker, model and type.
- Maker
- Ottobock SE & Co. KGaA
- Model
- C-Leg 4 microprocessor knee (3C98-3 / 3C88-3)
- Device type
- Prosthetic Limbs
- Main document
- Open the public document
Key specifications
What the public record says.
| Item | Value | Source |
|---|---|---|
| Mobility grade | MOBIS 2 to 4 | Source |
| Body weight limits | Maximum 136 kg including extra load; minimum 45 kg (lower possible after a successful trial fitting) | Source |
| Weight | About 1250 g without protective cover | Source |
| Maximum flexion | 130 degrees (122 degrees with preinstalled flexion stops) | Source |
| Protection rating | IP68; water resistant but not corrosion resistant, not for salt or chlorinated water | Source |
| Battery | Li-ion; at least 16 hours continuous walking or about 2 days average use; 80% charge after 4 hours, full after 8; keeps 80% capacity after 500 cycles | Source |
| Operating temperature | -10 to +60 C; charging +10 to +45 C | Source |
| Wireless | Bluetooth 5.0 Low Energy, about 10 m range, 2402 to 2480 MHz | Source |
| Structural test and lifetime | ISO 10328-P6-136 kg, 3 million load cycles; expected lifetime 6 years with prescribed maintenance | Source |
| Proximal connection | Pyramid (3C98-3) or threaded connector (3C88-3); tube clamp distally | Source |
Recalls
Recalls.
This note lists no recalls. Check the FDA recall database for the latest record.
Safety
Safety warnings from the record.
- Once the ongoing safety vibration has been given, the knee must not be used until an authorised Ottobock Service Centre has inspected it. Source
- In safety mode the damping behaviour changes and can cause falls; take particular care, for example on a fixed gear bicycle. Source
- The knee does not work while charging. Source
- Overheated components can cause burns if touched. Source
- Use only approved accessories, as others can reduce interference resistance and cause malfunction. Source
Sources
Where this note comes from.
- Ottobock C-Leg 3C98-3/3C88-3 instructions for use (qualified personnel), hosted by Ortoped
- Ottobock C-Leg 4 product page
- openFDA MAUDE problem counts, brand C-LEG
- openFDA recalls, recalling firm Ottobock
Not covered: No FDA recall for the C-Leg 4 was found (Ottobock recalls listed concern socket valves); the IFU signal table extracted poorly from the PDF, so the exact number of beeps for each low battery stage should be confirmed against the printed IFU, and service-level fault codes read by Ottobock software are not public.
BMEssentia knowledge drafted from public information, reviewed by Hasan Khaled Ismail on 2026-10-24. Always follow the manufacturer's instructions for use and service manual.
Prosthetic Limbs