Ulnar Head Replacement

There were 19 studies that reported 430 uniquely implanted ulnar head replacements (Table 31.1, Table 31.2, and Table 31.3). One study by van Schoonhoven et al is a long-term follow-up study of patients reported in a previously identified study. ¹⁹ The study by Willis et al ²⁰ originates from the same unit of that of Berger et al ¹⁰ ; it is not clear whether this is a new series of patients or whether this is a longer follow-up of the previously reported series. We have attempted to contact the authors to clarify this but without success. We have included this paper in our analysis and tables.

The implants used were predominantly the Herbert (KLS Martin Group) or the Avanta uHead (Small Bone Innovations) designs. Other implants (First Choice Ulnar Head replacement, Integra) were also used. In one study the implant was not stated. ³⁰ We attempted to contact the authors directly for clarification but without success. In six of the studies, a mixture of implants was used. One of these studies included the results of both ulnar head replacement and partial ulnar head replacement without separating the results by partial and total implant type. ³⁵ When assessing these papers, it was not always possible to identify separate results for each individual implant as they were reported as one dataset. ^{29 , 31 , 32 , 33 , 35 , 36}

There is considerable heterogeneity within the study populations. The study groups included patients with rheumatoid arthritis, other forms of inflammatory arthritis disease, primary osteoarthritis, posttraumatic arthritis, and patients who had had previous surgery, i.e., salvage procedures. For studies with a homogenous patient group, the most common indication was for failed prior resection arthroplasty.

Details of the reported results are variable. While some studies present detailed results of postoperative ranges of movement, grip strength, pain and function scores, 15 of the studies did not report one or more of these parameters. A number of the papers used their own outcome parameters. All of the papers stated that the majority of patients were happy with the results and described the outcomes as good.

The reported complication rates in these series are low (Table 31.4). These include residual instability of the distal ulna, infection, implant loosening, bone resorption, tendon rupture, and implant failure. Only two papers reported implant survival rates; these are stated as 83% at 6 years of follow-up using the Avanta implant and 90% at 15 years of follow-up using a mixture of implant types. ^{27 , 33} Overall 34 implant failures (removal or revision) were reported, giving an implant survival rate of 92% at a mean follow-up of 74 (range 17–132) months.

Total DRUJ Replacement

We identified 20 studies with a total of 448 implants (Table 31.5 and Table 31.6). All but two of these studies used the Aptis implant (Aptis Medical); the others used a prototype implant. Seven of the studies using the Aptis implant originate from the unit of the implant designer. It is stated that the senior author in one of these papers has treated more than 231 patients with this prosthesis. ^{11 , 37 , 38} We contacted Dr. Scheker directly to clarify how many of these papers report individual cases and how many were duplicates. He confirmed that the only paper in this series that includes previously published patients is that of Rampazzo et al. ³⁹ Therefore, this paper has been excluded from the survival analysis. There are other papers with crossover of patients; however, these did not meet the inclusion criteria for the review as they had too few implants, etc.

There is a considerable range of indications for total DRUJ replacement in these studies. While the majority had undergone previous surgery, there were some patients who had undergone primary DRUJ replacement and two papers where the indications were not stated. In those papers where there is a single indication for surgery this was most commonly salvage surgery following previous ulnar head excision.

The reported results are again variable. Only four of the papers report ranges of movement in all planes of movement, grip strength, pain and function scores. One paper uses its own scoring system. All papers report satisfactory or good outcomes with good patient satisfaction.

The reported complication rates are low. Complications include: infection (deep and superficial); heterotopic bone formation; tendonitis; bone resorption; implant fracture; screw irritation; loosening; and stress responses in the bones (Table 31.7). Twenty-five implant failures are reported in these studies; seven of these were in the series of prototype implants reported by Schuurman. ⁵⁴ There were no implant failures in the paper using the Stability implant (Small Bone Innovations). ⁵³ In the papers using the Aptis implants (381 implants), there were 16 revisions, i.e., an implant survival rate of 95.8% at a mean of 47.1 months (range 24–75 mo).