Wonderful 3FM12A-1

The 3FM12A-1 belongs in knee disarticulation limbs for people who spend real time on their feet without walking anywhere: cooking, washing up, ironing, working at a bench or serving behind a counter. A long through-knee residual limb bears weight well at its end, and a lock adds certainty that the joint below it will stay straight while the hands are occupied. Transfers are the second use, because the leg is loaded at an awkward angle as the user pivots.

Falls give the context. In a 2001 survey of 435 people living in the community with a lower-limb amputation, 52.4% had fallen in the past year and 49.2% feared falling. Amputation above the knee carried an odds ratio of 2.78 for falling. A 2020 study of 52 unilateral amputees in Portugal reported 36.5% with one or more falls in twelve months, all with minor injury. On locked walking, a 2002 crossover study of 14 older transfemoral amputees found 11 preferred a locked knee and walked 21% faster over two minutes with it. These samples are small or mixed, and none shows what any one joint does.

So the lock is a trade, and the service takes on its upkeep. A prosthetist decides where the pull runs and writes it down. At each review the pull and its fitting are examined, and replaced when wear shows. The user is taught to release before sitting and to feel for engagement on rising, then asked a week later how it went at home. Limb centres, rehabilitation wards and independent clinics can all carry that routine. NHS services in England buy through a mandated NHS Supply Chain framework, and equivalent public procurement elsewhere sets its own conditions. The conformity documentation those procurement routes require is issued by the manufacturer and shared by the enquiry team.

Buckling removed while the lock is engaged

A locked joint cannot fold under body weight. For the minutes spent standing at a worktop, that failure is off the list.

Both hands free at the counter

Nobody chops vegetables while holding a rail. With the leg held straight, the user's attention and both hands go to the task in front of them.

A steadier pivot in transfers

Moving between bed, chair and car seat loads the leg while the body turns. A straight, locked limb gives the user one fixed thing to turn on.

Hazards that can be named in advance

The four costs of this lock are known before the limb is built: the release step, wear in the pull, a missed re-lock and a stiff gait. Known hazards can be written into an assessment and given an owner.

Inspection that takes a minute

A pull and its end fitting can be looked at and tugged during any review. Early wear is visible, so replacement can be planned ahead of failure.

Deep bend for sitting once released

The sheet gives 165° of flexion. Once the lock is released, the shin can fold well under a chair, although socket trim and any cover reduce what a built limb reaches.

Aluminium at 752 g

Mass is printed beside the code. A through-knee limb already carries a long socket, so a moderate joint weight helps when the leg is lifted into a car.

No battery and no electrical testing

The joint is mechanical throughout. It needs no charger at home and sits outside a provider's electrical safety testing schedule.

Lock named in English and Chinese

The sheet's English name ends "with lock" and its Chinese name, 带锁机械膝离断, reads as locking mechanical knee disarticulation. The "-1" suffix denotes this locking version.

Looped cable with a small fitting in the photograph

A pale cable curls in a loop beside the joint and ends in a small fitting. It looks like a release, and the quotation lists whether it is supplied.

Release method per the instructions for use

Whether the lock is freed by a pull, a lever or another action is described in the manufacturer's instructions. The same document covers how the lock engages again.

Long angled arm on top

The photograph shows a slim metal arm rising at an angle from a curved base on the top of the body. It appears to anchor the joint to the socket, and the drawing gives its length and profile.

Black multi-link body

Below the arm sits a black body in which several links turn against each other. Their geometry, and the path the knee centre follows, appear in the manufacturer's documents.

Visible pivot pins

Four round pin heads show on the side of the body in the photograph, two higher and two lower. Pin and bush replacement is a question for the service schedule in the instructions.

Block-shaped lower end

The body narrows to a black block at its base in the photograph. The distal connection type and any tube diameter are given on the drawing.

Knee flexion range of 165°

This is the printed travel of the joint with the lock released. It is a bench figure for the bare component.

Mass of 752 g

The figure appears in brackets after the code. Add the release hardware and the top arm only if the quotation states they are outside it.

Load weight of 125 kg

One load figure is printed, with no loading level beside it. Both the level and the test set-up are recorded in the ISO 10328 report.

Aluminium construction

"AL" is the full material line. The technical file held by the manufacturer names the alloy grade and the surface finish.

Mechanical operation

No motor, sensor, battery, fluid cylinder or air cylinder is listed. Adjustments, where the instructions describe any, are made by hand at the bench.

Published EU declaration naming the code

A declaration under EU Regulation 2017/745, dated 26 June 2022 and published online in the manufacturer's name, lists this code with its locking description as Class I. Ask the enquiry team for the current signed copy.

Manufacturer's quality system

Wonderful's website describes an ISO 13485 quality management system. The certificate, its scope and its expiry date come from the enquiry team.

Choose the 3FM12A-1 for a through-knee user whose day includes long standing jobs and who can reliably work a manual release. The lock takes buckling out of those minutes, and the service accepts a pull to route, inspect and teach in return. Pass on it for wearers above 125 kg, for anyone who may not manage the release step, and for prescriptions needing a brake or fluid control. Then settle three things: the lock type and release hardware supplied, the test level behind the load rating, and the connections at each end.

Medigear.uk lists the 3FM12A-1 for business buyers worldwide and can arrange delivery, installation, commissioning, familiarisation and service cover. Ask the enquiry team for the lock and release instructions, ISO 10328 test report, drawing and declaration of conformity before ordering.