Keywords
ulnar head arthroplasty - DRUJ prosthesis - total wrist arthroplasty - ulnar head
prosthesis - uHead prosthesis
Various implants have been described for ulnar head replacement (UHR)[1]
[2]
[3]
[4]
[5] or for total replacement of the distal radioulnar joint (DRUJ).[6]
[7]
[8]
[9] Many series are small[10]
[11]
[12] and few report on mid- or long-term results. Some of the reports include several
different ulnar head implants.[13]
[14]
Radiocarpal osteoarthritis and DRUJ osteoarthritis may coexist. In these patients,
joint degeneration usually begins in the radiocarpal and intracarpal joints and after
some time, degeneration of the DRUJ gradually follows. In rheumatoid arthritis, this
pattern is usually reversed, the degeneration beginning in the DRUJ and later affecting
the wrist joint. Also malunited intra-articular distal radial fractures may lead to
osteoarthritis of both joints. In all these instances, a combination of a radiocarpal
prosthesis and an ulnar head implant for the DRUJ is a possible option for patients
who want a motion preserving solution. To our knowledge, no series have been published
reporting on this combination.
This study primarily aimed to report on the midterm results after ulnar head only
and total DRUJ replacement using the uHead (Stryker, Kalamazoo, MI) in the treatment
of painful disorders of the DRUJ. The secondary aim of the study was to assess the
combination of UHR and total wrist arthroplasty (TWA).
Materials and Methods
Patient Inclusion and Data Collection
We included 20 consecutive patients in whom an UHR with the uHead was performed at
our institution between February 2005 and March 2017. All patients gave written informed
consent for the use of their medical data in this study, according to the ethical
and patient-safety standards in Denmark. Approval was obtained from Danish Patient
Safety Authority under reference: 31–1521–198.
Data were recorded prospectively before operation and at follow-up examinations and
entered in a registry. The patients were followed-up at 3 and 6 weeks and 3, 6, and
12 months postoperatively and thereafter annually. Clinical assessment included wrist
range of motion (ROM) and forearm rotation measured with a goniometer, and grip strength
measured with a Jamar hydraulic hand dynamometer (Performance Health, Warrenville
IL). Patient-reported functional outcomes were assessed with the Danish version of
the quick disability of arm, shoulder, and hand questionnaire (qDASH). The general
pain level was recorded on a visual analogue scale (VAS) from 0 to 100, 0 indicating
no pain and 100 maximal pain. Radiographic examination included plain posteroanterior
and lateral views.
Implant Design
The uHead consists of a cobalt-chrome stem and semispherical head. The stem is titanium
coated and can be press fitted or cemented in the medullary canal of the ulna. The
prosthesis has two stem options: a standard collar or an extended collar for secondary
procedures such as failed distal ulna resections. A polyethylene component on a metal
tray called stability,[12] can be used as an option to replace the radial sigmoid notch ([Fig. 1]).
Fig. 1 Septic arthritis of the distal radioulnar joint treated with total joint replacement
(uHead plus stability). (A) Destroyed distal radioulnar joint, (B) 3-year after joint replacement.
Indications
Indication for uHead implantation was severely painful destruction of the DRUJ that
did not respond adequately to nonoperative treatment. In three cases, the stability
component was used, additionally. The indication for using stability was previous
infection of the DRUJ in one case, failed Sauvé–Kapandji procedure in one case and
DRUJ osteoarthritis with a step-like deformity of the sigmoid notch in one case.
Operative Procedure and Postoperative Regime
Three consultant surgeons performed the UHR. The operation was performed under lateral
infraclavicular block and tourniquet control and according to the manufacturer's indications.
In five cases, the uHead was implanted simultaneously with a Remotion TWA (Stryker,
Kalamazoo, MI; [Fig. 2]). In four cases, a Remotion TWA had been implanted previously.
Fig. 2 62-year-old woman with a combined TWA and UHR arthroplasty, radiological status at
a 14 years follow-up. UHR, ulnar head replacement; TWA, total wrist arthroplasty.
Twelve patients have been operated before UHR. The total number of previous wrist
surgical procedures were 22 (range: 1–5), thus leaving eight patients in whom UHR
implant was a primary wrist surgical procedure. Postoperatively, the extremity was
immobilized during 2 to 6 weeks in a below-the-elbow cast or splint in 15 cases. In
one case an above-the-elbow splint was used for 3 weeks. The remaining cases had soft
dressing bandages only. After removal of the cast or splint, hand therapy was started.
Statistics
Kaplan–Meier survival analysis was used to estimate the cumulative probability of
remaining free of revision (i.e., reoperation with total or partial removal of the
implants). A nonparametric Wilcoxon's signed-rank test was used for comparing data
not normally distributed (qDASH scores), and the paired parametric Student's t-test was used for normally distributed data (pain and VAS scores, range of motion,
and grip strength). Significance was set at a p-value of less than 0.05.
Results
Demographics
There were 6 men and 14 women with mean age of 59 years (range: 36–80 years). Among
them, 14 were operated on the right and 6 on the left side, 13 being dominant hands.
The underlying condition was idiopathic degenerative arthritis in nine cases, posttraumatic
arthritis in seven, and inflammatory rheumatoid arthritis in four. Of the posttraumatic
cases, three had a malunited distal radial fracture, one had a Galeazzi's type forearm
fracture, one had a scaphoid nonunion advanced collapse (SNAC), one had sequelae after
a triangular fibrocartilage complex (TFCC) injury, and one had a previous infection
of the DRUJ ([Fig. 1]). Operation time averaged 99 (range: 45–180) minutes and tourniquet time averaged
97 (range: 45–172) minutes.
Clinical Results at Follow-up
Three patients died from unrelated causes. None of these cases had been revised. One
patient died 5 months after operation. This patient was not included in the analysis
of the clinical results. Neither did three patients who had been revised. The mean
follow-up time in the remaining 16 patients was 5 years (range: 2–15 years). The clinical
results are summarized in [Table 1]. Wrist extension, flexion, and ulnar and radial deviation did not change to a clinically
or statistically significant extend and are therefore not presented in the table.
Table 1
The clinical results of the study
|
Measure
|
Type of replacement
|
|
uHead alone
|
uHead + Remotion
|
uHead + stability
|
Total[a]
|
|
Number of patients:
|
6
|
7
|
3
|
16
|
|
Pain (VAS score) Mean (range)
|
|
Preoperative
|
58 (16–92)
|
66 (38–97)
|
72 (55–83)
|
66 (16–97)
|
|
Postoperative
|
21 (0–51)
|
14 (0–45)
|
13 (0–33)
|
16 (0–51)
p < 0.001
|
|
Function (qDASH score) Median (range)
|
|
Preoperative
|
56 (52–59)
|
55 (45–68)
|
54 (36–75)
|
56 (36–75)
|
|
Postoperative
|
21 (5–47)
|
22 (4–47)
|
6 (4–18)
|
19 (4–47)
p < 0.006
|
|
Grip strength (kgF) Mean (range)
|
|
Preoperative
|
10 (4–20)
|
15 (7–22)
|
10 (6–12)
|
12 (4–22)
|
|
Postoperative
|
20 (8–30)
|
24 (16–30)
|
19(6–36)
|
21(6–36)
p = 0.005
|
|
Pronation (degrees) Mean (range)
|
|
Preoperative
|
73 (60–85)
|
76 (60–90)
|
77 (70–80)
|
75 (60–90)
|
|
Postoperative
|
73 (60–90)
|
74 (60–90)
|
77 (70–80)
|
75 (60–90)
p = 0.92
|
|
Supination (degrees) Mean (range)
|
|
Preoperative
|
70 (10–100)
|
79 (65–90)
|
85 (80–95)
|
77 (10–100)
|
|
Postoperative
|
63 (45–80)
|
78 (60–95)
|
77 (70–80)
|
73 (45–95)
p = 0.54
|
|
Satisfaction (number of patients)
|
|
(Very) satisfied
|
6
|
7
|
3
|
16
|
|
(Very) disappointed
|
0
|
0
|
0
|
0
|
Abbreviations: qDASH, quick disabilities of the arm, shoulder, and hand; VAS, visual
analogue score.
a Three revised patients and one patient who died 5 months after operation excluded.
Osteolysis, Revision Rate, and Cumulated Implant Survival
In all cases, osteolysis at the collar of the implant already showed on radiographs
after 3 months. At the final follow-up, the mean width of the osteolytic area was
4 mm (range: 2–17 mm) without having caused implant subsidence.
Three UHRs were revised. In one patient with an isolated UHR, the implant was removed
after 1.5 years due to persistent pain and restricted supination. Two patients, both
diagnosed with a rheumatoid arthritis (RA) of the wrist, with combined UHR and TWA,
had ultimately both implants revised. One of these two patients was originally operated
in another institution, with a Remotion TWA. When seen by us 5 years later, due to
painful rheumatoid arthritis of the DRUJ, the patient was offered an ulnar head prosthesis.
Surgery went successfully but we had to remove the implant after 1 year because of
persistent pain and instability of the DRUJ. Ten years after the initial TWA the patient
fell and dislocated the TWA. Closed reduction and later replacement with a thicker
polyethylene insert failed in stabilizing the wrist and finally a wrist arthrodesis
was performed.
In the second patient, a TWA was originally performed. After 4 years, the implant
was revised because of subsidence of both components. One year later, an UHR was performed
because of pain and degenerative disorder of the DRUJ. After 1.5 years, the patient
developed wrist pain, swelling, fever, and high levels of C-reactive protein (CRP)
and leukocyte was suggestive to infection. Bacteriological cultures revealed Staphylococcus epidermidis. All the implants were removed. A relevant antibiotic treatment was given for 3 months,
the patient's wrist/DRUJ was temporary immobilized with a removable orthosis and finally
a total wrist arthrodesis was performed.
The cumulative survival rate curve in the total cohort is shown in [Fig. 3].
Fig. 3 Implant survival. The probability of revision is visualized in the graph below. The
solid line indicates the probability of implant survival and the dashed lines are
the corresponding 95% confidence bands. Patients are censored at their last visit.
The numbers at risk on the X-axis indicate the patients that did not experienced revision
within the period they were observed.
Discussion
While three of the 20 patients in our cohort had to be revised because of pain problems
and/or unsatisfactory forearm rotation in two cases and infection in one, 17 had an
uncomplicated postoperative course. All these patients were satisfied with the result.
The clinical outcomes in the nonrevised patients in our study are similar to those
reported in other publications with isolated UHR.[15]
[16]
[17]
[18]
[19]
[20] Pain, function, and grip strength, all were improved, while motion did not change
clinically or statistically significant. Three of our patients had to be revised.
However, our cumulated implant survival and complication rate correspond well with
what is generally reported.[21]
[22]
In the recent systematic review presented by Moulton and Giddins,[22] the authors found the total complication and revision rate of 28 % (100 out of total
355 cases) in the reports of UHRs and correspondingly, in 28% (88 out of 315 cases)
in reports of total DRUJ arthroplasties. Only the complicated cases that need surgery
were counted. The implant survival rate was 93% at a mean follow of 45 months and
97% at a mean of 56 months in reports of UHR and total DRUJ replacements, respectively.
It must be noted that two of the revisions in our series were needed in complex cases
of combined UHR and TWA. The most common complications reported in the literature
are instability and sigmoid notch erosion. We encountered instability in one case
only and sigmoid notch erosion was not a problem in our series. We tried to avoid
this problem by using the stability component in selected cases. It was used in three
cases without complications; this unconstrained but total DRUJ replacement efficiently
improves the stability of the joint and can safely be used in a situation where total
DRUJ replacement is required, as an alternative to a semiconstrained total DRUJ implant
design. However, further results with larger series are needed to support this evidence.
Bone resorption at the prosthetic neck is frequently encountered. It tends to stabilize
with time and does not cause prosthetic loosening.[15] Our findings agree with this opinion in none of our cases this osteolysis had caused
prosthetic subsidence. All three revisions were performed in an early stage when bone
resorption was not important.
In the studies of Axelsson et al[16] and Kakar et al,[18] authors found previous surgery of the wrist to constitute a risk of poor outcome.
These findings were observed as a tendency, without statistical significance. We could
not confirm that an extended collar constituted a risk factor, as supposed by Kakar
et al.
Strength and Limitations
One strength of our study is that we were able to report on combined UHR and TWA,
which we have not encountered in other publications. UHR without the use of stability
makes it possible to perform a simultaneous TWA if needed. In our cases, the clinical
results after combined UHR and TWA were similar to those after simple UHR. Another
strength of the study is that we had preoperative clinical data on all patients and
that we systematically did follow-up examinations.
The limitation of our study is the relatively small number of cases, especially in
the subgroups. For this reason, we decided not to make any calculation of significance
in comparing combined cases with UHR only cases. Another weakness is the lack of control
with other procedures, first of all ulnar head resection, the Sauvé–Kapandji procedure,
and the frequently used semiconstrained total DRUJ prosthesis, Aptis (Aptis Medical,
Glenview, KY).[23] Especially, we cannot conclude on the possible benefit of using UHR rather than
Darrach's procedure when performing TWA in cases that also have a destroyed DRUJ.
Conclusion
Ulnar head arthroplasty (uHead) showed significant improvement in pain, grip strength,
and the function of the patients with a painful disability of the DRUJ, without impairment
on mobility on the midterm follow-up. The overall implant survival over the time and
the complication rate was acceptable.
