Hosmer Hooks are body-powered terminal devices for people with an upper limb difference. There are several models that range in shape, weight, and the materials they are made from. A clinician who specializes in upper limb prosthetic care can help you select the best body-powered hook that fits your size and daily tasks, but we’ll give you an idea of the different options.

Each of these hooks have metal “tines” that are operated with upper body motion, specifically shoulder and back motion captured by a harness that’s attached to a control cable. The motion pulls the cable and opens the hook which then closes as the user relaxes. The amount of force needed is adjusted by adding or removing hook tension bands (industrial strength rubber bands). Most people use three to five bands, which equates to roughly three to five pounds of pinch force (this is a good amount for a prosthesis, though it is less than a sound hand’s pinch force). In some atypical cases, they can also be operated passively using the sound hand to toggle the lever. You can watch how the hook opens in the gif below:

bp_hook_demo.2022-02-04 13_01_40

The hook we probably fit our patients with most often is the Hosmer #5XTi Hook. It is the newest version of the classic #5 hook that has “canted” tines— tines that are at an angle from the opening axis. The “Ti” in the model number means it is made of titanium and weighs 4.2 ounces — pretty light! The X means it has a rubber lining on the inside of the tines. For people engaging in heavy-duty tasks, this is going to be a great device. Our prosthetists frequently recommend this device for several reasons: it’s easy for the patient to see what they’re grasping, the lining on the tines provides a good grip and doesn’t scratch objects, and the titanium is a great combination of strength and weight.

Our patient Ernesto uses his 5XTi for work tasks. Ernesto operates heavy machinery to clear land for construction and also assists with maintenance on the machines. He’s able to manipulate tools such as wrenches and ratchets with his hook. He uses the hook for a multitude of tasks including lifting buckets and clearing debris. After being fit with a prosthesis, Ernesto has been able to resume operating a backhoe and is able to manipulate the controls with his prosthesis, using the fine motor skills he is practicing below.

TimErnesto-Listing

For people with a job or hobby that’s going to be rough on their hook, using a stainless-steel hook with serrated tines (think criss-cross grooves instead of a rubber lined hook) can increase the durability. The Hosmer #555-SS Hook fits that bill and has symmetrical tines that are shaped like a “lyre” and provide a cylindrical grasp on round items like bottles and cans. Because it’s made of stainless steel, it weighs in at 8.5 ounces, over twice the weight of the 5XTi. But if you want your device to stand up to nearly anything you can throw at it, this may be the right hook for you. Our patient Abram worked for 32 years repairing machines at a flour mill. After he lost his left hand on the job, he wanted to be able to continue doing tasks like welding (see below), which is helped by the serrated tines. Abram was also determined to continue working with his son on customizing 4X4s for off-roading.

Abe uses a body-powered option for welding.

The 5XA is another take in the model 5 line of hooks. This device is made from aluminum and weighs in at 4 ounces, making it the lightest. While the 5XA is available in a standard aluminum finish, it’s also possible to customize the color of the hook in blue, black, red or gold, with an extra charge for red or gold.

There are also hooks available for adults with smaller stature, teens, and even children. Hook models 8 and 9 serve that population and work the same way as their larger counterparts.

Lastly, when a patient needs to go big or go home, the model 7 hook, or “farmers” hook, has the largest opening and is the heaviest-duty hook available. It weighs in at a whopping 11 oz, or almost three times that of the 5XTi, which is overkill for most people, but for some it may be exactly what they need. Our patient John, who is a farmer, is using his model 7 hook to drive his tractor:

John Mitchell operating tractor.jpg

While Hosmer hooks are often recommended for our patients, there are other body-powered hooks available. The V2P (pictured below) is made by Toughware and stands for Variable Pinch-force Prehensor™. What sets it apart from the hooks mentioned above is that it has six settings for adjusting the amount of pinch force that’s available to the user. Depending on the desired activity, the pinch force can be manually changed from a light grip to stronger grips. The V2P features rubber pads and opens wider than the previously mentioned hooks.

Marissa Rotenberry  V2P

Each of the patients above has at least one other prosthesis that they wear. Hooks are great for all sorts of tasks, but because they are body-powered, the amount of force and movement that’s needed to open and close them can become tiring. Additionally, using only a body-powered device can lead to overuse issues. These issues can be mediated by proper body mechanics as taught to you by an occupational therapist (one of the reasons we have full-time occupational therapists at each of our centers). But if it’s possible to have a body-powered hook and another type of prosthesis, the wear and tear on the body will be less.

Your prosthetist will be able to help you decide which device will work best for your Activities of Daily Living, your work tasks and your hobbies. Once you’re fit with a prosthesis your occupational therapist will help you learn how to use it. Our support team is with you every step of the way, starting with a complimentary consultation  please contact us if you’d like an in-person or video consultation for yourself or someone you know. If you’d like to leave a comment on this article, please do so below.

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