Rhizarthrosis—the Most Common Form of Osteoarthritis in the Hand: An Expert Interview with Dr. Hubert Klauser, M.D.

Dr. Hubert Klauser, M.D., is a renowned specialist in foot surgery, ankle surgery, sports traumatology, and hand surgery, who brings his expertise to the HAND- UND FUSSZENTRUM BERLIN. As the medical director of the center, Dr. Klauser not only brings extensive experience in the diagnosis and treatment of hand and foot conditions, but has also made significant contributions to the advancement of orthopedics through the development of innovative implants. Dr. Klauser has made a name for himself in particular through his pioneering work in the field of forefoot surgery and hallux valgus treatment. In this work, he uses advanced, magnesium-based, and bioresorbable implants that he helped develop himself. These implants offer the advantage of promoting natural bone regeneration and do not require follow-up surgeries to remove metal. The positive efficacy of this technology is supported by scientific studies and numerous successful applications.

In addition, Dr. Klauser is recognized as the author of numerous professional publications and is actively involved as an orthopedic consultant and instructor. His experience and knowledge benefit not only his patients but also the professional community, as he shares his insights at national and international conferences. Dr. Klauser offers comprehensive treatment options for patients of all ages, including athletes and individuals with complex orthopedic needs. His expertise in functional orthopedics and sports orthopedics complements his broad range of treatments and is reflected in his patient-centered practice. Dr. Klauser is committed to providing sound and modern orthopedic care based on both innovative techniques and proven treatment methods.

Rhizarthrosis is the most common form of osteoarthritis affecting the hand, and the editorial team of the Leading Medicine Guide was able to speak with Dr. Klauser specifically about this condition.

Osteoarthritis is a widespread joint disease characterized by the progressive breakdown of cartilage tissue in the joints. This process leads to a variety of symptoms, including pain, stiffness, and limited mobility. The condition can affect any joint but is particularly common in the knees, hips, and hands. Symptoms usually develop gradually and worsen over time, which can lead to a significant impairment of quality of life. The causes of osteoarthritis are diverse and range from age-related changes and genetic predispositions to injuries and joint overuse. While there is no cure for osteoarthritis, various therapeutic approaches—such as medication, physical therapy, and surgical interventions—can help alleviate symptoms and preserve the function of the affected joints.

Rhizarthrosis is a specific form of osteoarthritis that affects the so-called thumb saddle joint (thumb base joint), i.e., the joint at the base of the thumb. This condition leads to a gradual breakdown of the cartilage in the joint, resulting in pain, stiffness, and limited mobility of the thumb. Rhizarthrosis is common in older adults but can also occur in younger people due to overuse or injury. Symptoms typically include pain when moving the thumb—especially during grasping motions—and increasing weakness of the thumb. 

The thumb saddle joint plays a central role in the mobility and function of the thumb. 

It is located at the base of the thumb, where the first metacarpal bone articulates with the trapezium bone (os trapezium) of the wrist. This joint enables a wide range of movements that are essential for everyday tasks. “If you translate the word ‘rhizarthrosis,’ which comes from Greek, ‘rhizon’ means ‘root.’ Of particular note is the thumb’s ability to oppose—that is, to move toward the palm—which enables it to grasp and hold objects. Repositioning—the movement in which the thumb returns to its starting position—is also an important function. Flexion and extension—the bending and straightening of the thumb—as well as abduction and adduction—the movements away from and back toward the palm—are also crucial for precise hand movements. These movements are essential for numerous everyday activities such as writing, grasping objects, and doing crafts. The thumb saddle joint thus contributes significantly to the hand’s functionality and dexterity and enables a wide variety of complex hand movements, which makes the thumb—and thus the hand—unique. And if the thumb saddle joint does not function properly, the hand’s grasping ability is also significantly impaired. It is also important to note that the thumb joint is not a ball-and-socket joint, but rather an egg-shaped joint. “This means there is no joint position in which the joint surfaces glide congruently relative to one another—as is the case with the hip, for example—and therefore, wear on the joint surfaces also varies,” explains Dr. Klauser at the beginning of our conversation.

The first symptoms of rhizarthrosis usually manifest as pain and limited mobility in the thumb. 

Initially, symptoms may occur particularly during certain activities, such as grasping objects or opening jars. Pain may also be felt during everyday tasks such as holding a pen or lifting bags. This pain often occurs during activity and, as the condition progresses, may also be felt at rest. “The person affected may notice the symptoms, for example, when a bottle slips out of their hand while trying to open it. Or the thumb may hurt when trying to turn a key in a door. Some patients are unable to grasp objects at all. Discomfort also occurs at the base of the thumb. This is caused by inflammation that develops in the thumb saddle joint when a person has osteoarthritis. In addition to the pain, advanced stages are accompanied by significant limitations in movement. My experience with patients varies greatly. With some, I’m often surprised that despite having stage IV osteoarthritis, the pain isn’t yet very severe, whereas other patients with stage II osteoarthritis experience significant pain and may already require surgery. So it varies widely. “You can’t determine the severity of pain based on X-ray imaging alone,” explains Dr. Klauser.

The process of cartilage degeneration often begins with tiny tears and irregularities in the cartilage, which gradually expand. Over time, the cartilage becomes thinner and loses its smooth, elastic structure. As the cartilage continues to break down, the protective layer between the bone ends becomes increasingly thin, until eventually bone can rub against bone. This direct rubbing of the bone ends causes severe pain and inflammation. The loss of cartilage reduces the space that normally forms the joint space. The joint space, which is visible on X-rays as the space between the bones, becomes increasingly narrow. This narrowed joint space is a typical radiological sign of osteoarthritis. The more the cartilage breaks down, the less space remains between the bones, and the joint space becomes correspondingly narrower. In addition to the narrowing of the joint space, bone spurs (osteophytes) may form along the edges of the joint, further restricting the range of motion and causing pain. Chronic inflammation can lead to swelling and further damage to the joint structures. Ultimately, this process results in a significant limitation of mobility and function in the thumb saddle joint, making everyday activities such as grasping and holding objects more difficult.

“When the first symptoms appear, patients are given a so-called Rhizoring orthosis, which encircles the thumb saddle joint with a silicone ring. The thumb remains completely free and can move fully, while the joint itself is stabilized without being immobilized. In addition, there are laser and magnetic field therapies, and if the pain is more severe and a more aggressive approach is desired, radial shock wave therapy can also be performed, though this is relatively painful. I recommend magnetic field therapy first, because if patients—mostly women—also have osteoarthritis of the finger joints, both hands can be treated effectively. However, this is only suitable in the early stages. In addition, cortisone injections can be administered. However, the joint space must not be too narrow for this; otherwise, the injections are not effective. Injections of hyaluronic acid or autologous blood can also help, though it is often difficult to reach the joint with the injection. Physical and occupational therapy can also help. Another option offered is X-ray stimulation therapy, which I personally do not endorse due to the radiation exposure, and the therapy’s effectiveness is also too short-lived,” explains Dr. Klauser.

Total thumb saddle joint replacement (TEP) offers several specific advantages over traditional treatment methods for rhizarthrosis, particularly when conservative measures are no longer sufficient to control symptoms and improve joint function.

A key advantage of the thumb saddle joint TEP is the significant pain relief it can provide to patients. Compared to conservative methods, which often provide only temporary relief or aim for symptomatic improvement, the prosthesis can offer a lasting solution to pain while maintaining full range of motion. “The HEMI prosthesis, a partial endoprosthesis, has not proven effective for the thumb saddle joint. I have been using TEP for 20 years, always the same model with certain modifications, which has proven successful. Resection arthroplasty, also known as Epping plasty, has been in use for 40 years. In this procedure, the trapezium (the joint partner of the first metacarpal bone) is removed to eliminate the painful contact between the joint surfaces. The disadvantage of this outdated surgical method is that, over time, the first metacarpal bone slips onto the next carpal bone—namely, the scaphoid. After the bone is removed, an interposition arthroplasty is therefore performed, usually using a tendon, to ensure the stability of the joint. However, a tendon is not vital; it can tear or thin out. To improve this, the idea was developed to take a portion of the tendon and attach it to the first and second metacarpal bones—a suspension arthroplasty. To do this, a hole is drilled at the base of the second metacarpal bone, and a tendon from the thumb is threaded through this hole in the second metacarpal bone and through the first metacarpal bone, thereby preventing the first metacarpal bone from sliding onto the scaphoid. This approach works reasonably well, but it’s a laborious surgery, and people haven’t been entirely satisfied with the results. Then there’s the option of fusing the thumb saddle joint with screws and plates. This naturally limits range of motion. “However, it’s possible to perform the fusion in a way that allows patients to cope quite well with it,” explains Dr. Klauser, before returning to the topic of TEP:

“The TEP, which is usually made of titanium (hydroxyapatite-coated to optimize healing) and has a polyethylene insert, is currently experiencing a boom and widespread acceptance. The main advantages of a TEP are its strength, excellent mobility, and a short rehabilitation period. A TEP is a viable option for almost every patient, except when the adjacent joint—the scaphoid-trapezium-trapezoid joint (STT joint between the scaphoid, trapezium, and trapezoid bones)—is also arthritic. In such cases, the patient would not benefit from a TEP, as pain originates not only from the thumb saddle joint but also from the STT joint. In this situation, resection arthroplasty is a more appropriate option. The average duration of a TEP procedure is 35–45 minutes. To perform this procedure, the base of the first metacarpal bone is carefully resected, the stem of the endoprosthesis is milled into the first metacarpal bone and implanted, and the socket seat for the TEP cup is milled into the trapezium. The entire assembly then resembles a miniature hip endoprosthesis. The head-and-neck component can then be inserted between the cup and the stem, with the appropriate length and flexion. As far as durability is concerned, no long-term studies are available yet. In one of my patients, whom I treated with a TEP in 2004, the prosthesis is still holding up. About 15 years is the norm. So far, I haven’t had to revise—that is, remove—any TEPs.”

Depending on the material and the load it bears, the prosthesis can last many years, ensuring long-term stability and functionality. Ultimately, the thumb saddle joint TEP reduces the need for repeated surgical procedures or ongoing conservative treatments that may become necessary as the condition progresses. Implanting a TEP minimizes the risk of persistent inflammation and the breakdown of adjacent tissue, leading to a more stable and sustainable solution.

As with any surgical procedure, there are risks and potential complications associated with the implantation of a thumb saddle joint total endoprosthesis (TEP) that patients should be aware of. 

“A high level of expertise is essential for performing TEP surgery, and the learning curve is steep. It takes about 100 surgeries to gain a sufficient level of experience. The most challenging part of the surgery is inserting the cup. One must be careful when rasping the metacarpal bone to insert the TEP stem, as it can fracture. And when milling the socket site for the ‘press-fit’ procedure, you cannot make corrections as often as you like, as this could cause the trapezium to fracture. After all, the bone no longer possesses the elasticity of youth. However, this happens extremely rarely. “Over the past 20 years, I have successfully implanted over 1,000 DSG TEPs, so I am well-positioned to assess the challenges involved,” states Dr. Klauser.

Postoperative rehabilitation following the implantation of a thumb saddle joint total endoprosthesis (TEP) plays a crucial role in the success of the procedure and the patient’s return to normal activities. 

“The patient typically stays in the hospital for two nights. Ten to fifteen years ago, I performed these surgeries on an outpatient basis, but I now perform them on an inpatient basis again because the hygiene standards in outpatient surgical centers are not adequate for such joint replacement procedures. Rehabilitation after a TEP is very quick. A plastic splint is applied over the thumb for two weeks, and the patient is then fitted with a brace that still allows the fingers to move. Then physical, occupational, or hand therapy begins, and after six weeks at the latest, the patient is fully fit for everyday life again,” Dr. Klauser explains, adding a personal wish: “The current situation is very good, and I’m satisfied with the quality of the TEPs. We also have what’s known as ‘double mobility’ here, meaning that with the TEP, the head rotates freely within the socket, which also provides increased protection against dislocation. This was modeled after hip replacement surgery. Personally, I would like to see even greater acceptance among my hand surgery colleagues for the implantation of a DSG TEP.” And with that, we conclude our conversation.

Thank you very much, Dr. Klauser, for giving us such a great insight into the complexity of the hand!