A 30 year old lady with an incidental finding of a carpal coalition
A 30 year old caucasian lady presented to the accident and emergency department complaining of pain on the dorsal aspect of the wrist. This was precipitated by a fall on the dorsiflexed left wrist. She was initially treated with immobilisation in a splint and was reviewed a week later in the fracture clinic. Examination showed a reduced range of motion at the wrist joint due to pain with 30 degrees of dorsiflexion, 20 degrees of palmer flexion, 5 degrees of radial deviation and 15 degrees of ulnar deviation. There was generalised temderness over the dorsum of the wrist joint. Radiographs showed a fused lunate and triquetrum with no evidence of fracture (figure 1 and 2). The patient was treated conservatively with splintage for a further two weeks by which point, the patients symptoms had resolved and she was discharged from the clinic.
The carpal bones are the most common site of coalition in the body. The lunate and triquetrum are most frequently involved followed by the capitate and hamate1. Carpal coalition is most commonly found in females and people of an African origin. There is also a bilateral incidence of approximately 60%2. Embryologically, the upper limb bud becomes visible towards the end of the 4th week in utero. Over the next 3 to 4 weeks, the sites of future bones and joints become demarcated due to apoptotic cell death leading to cleft formation and joint development. Failure of this cleft formation results in carpal coalition3. Carpal coalitions may form part of a congenital syndrome, the most common being arthrogryposis, synphalangia, hand-foot-uterus and chondroectodermal dysplasia4. DeVilliers Minnaar has classified lunotriquetral coalition into four major categories as follows5 1) Type I- Incomplete carpal coalition resembling a pseudoarthrosis 2) Type II- Fusion with a notch at the site of the usual division between two bones 3) Type III Complete fusion 4) Type IV Complete fusion with other carpal anomalies. In our case, figure 1 shows a Minnaar Type III coalition. Complete coalition is not known to be symptomatic, however, incomplete coalitions have been reported to be a cause of wrist pain6. These cases are usually treated with a lunotriquetral fusion which usually has good results. This is normally achieved by removing the remaining cartilage and compressing the two bones using a Herbert screw.
Minnaar Type III lunotriquetral coalition
Based on the provided wrist X-ray in posteroanterior (Figure 1) and lateral views (Figure 2), complete bony fusion can be seen between the lunate and triquetrum, with no apparent joint space or pseudoarthrosis. The fusion is a complete and continuous bony union, consistent with the Type III characteristic of lunotriquetral coalition described by DeVilliers Minnaar. The surrounding carpal bones appear largely normal in morphology, with no obvious fractures, bone destruction, or soft tissue swelling.
Considering the patient is a 30-year-old female with no significant symptoms, and imaging shows a complete (Type III) fusion between the lunate and triquetrum, the most likely diagnosis is: Congenital Complete Lunotriquetral Coalition (Carpal Coalition, Minnaar Type III). Since this type of fusion often does not cause obvious clinical symptoms, special treatment is usually not required in most cases.
If the patient does not have wrist pain or restricted movement, regular follow-up observation is generally sufficient. If any of the following occur, further intervention may be considered:
Daily exercise and rehabilitation, in the absence of significant pain or limitation, typically focus on maintaining joint flexibility and muscle strength, following the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, Volume). Specific examples are as follows:
When increasing the load on the wrist joint, closely monitor any increase in pain, swelling, or other discomfort. If any abnormalities are noted, seek medical advice or adjust the training plan promptly.
Disclaimer: The above report is for reference only and cannot replace an in-person consultation or the professional diagnosis and treatment advice of a physician. If you have any questions or if symptoms worsen, please consult a specialist immediately.
Minnaar Type III lunotriquetral coalition
