Resurfacing humeral prosthesis: do we really reconstruct
Pierre Mansat, MD, PhD*, Anne-Sophie Couti? e, MD, Nicolas Bonnevialle, MD,
Michel Rongi? eres, MD, Michel Mansat, MD, Paul Bonnevialle, MD
Orthopedic and Traumatology Department, Centre Hospitalier Universitaire de Toulouse Purpan, Toulouse, France
Background: The goal of a resurfacing shoulder arthroplasty is to reproduce the individual’s anatomy
while preserving the bone stock of the humeral head. This study investigated the hypothesis that
resurfacing the humeral prosthesis restores normal glenohumeral relationships and correlates with the
final clinical results.
Materials and methods: A resurfacing shoulder implant was performed in 61 patients (64 shoulders).
Indications were primary osteoarthritis in 26, secondary osteoarthritis in 21, avascular necrosis in 4,
rheumatoid arthritis in 4, dysplasia in 4, and for others indications in 5.
Results: At an average of 36 months (range, 24-65) of follow-up , the Constant score reached 68 points
and the Quick-Disabilities of Arm, Shoulder and Hand score reached 28 points. Preoperative and
postoperative radiographic analysis showed a decrease of the humeral head diameter (51 ? 5 vs 48 ? 5
mm) and of the height of the humeral head (21 ? 4 vs 19 ? 2 mm), without modification of the radius
of curvature or the height of the center of rotation. The medial humeral offset increased from 3.3 ? 3.5
to 6.4 ? 3 mm and the lateral offset from 6.8 ? 9 to 10.4 ? 9 mm. The implant was mainly in varus
postoperatively compared with preoperative values (122?? 11?vs 134?? 7?). Postoperative radiographic
analysis and at the last follow-up did not show any significant difference, except for the increase of the
depth of the glenoid from 4.2 ? 1.4 to 4.9 ? 1.8 mm.
Conclusions: The resurfacing shoulder arthroplasty reproduces the normal anatomy and compensates
glenohumeral wear. However, there was a tendency to position the prosthesis in varus because of technical
imperfections. With follow-up, medialization of the humerus with glenoid wear was observed and was
correlated in some patients with reappearance of pain.
Level of evidence: Level IV, Case Series, Treatment Study.
? 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.
Keywords: Shoulder; arthroplasty; surface replacement; hemiarthroplasty
Initially, the resurfacing humeral prosthesis was used in
Scandinavia to treat rheumatoid shoulders.1,17,31However,
Copeland et al18-21were the first to apply this concept to
treat all degenerative shoulder lesions. The goal of this
procedure was to replicate the individual’s anatomy of the
humeral head and the lateral offset of the proximal humerus
while preserving the humeral bone stock.6The resurfacing
Institutional Review Board approval was not required when the patients
were included in this study. All patients gave their consent for their clinical
and radiographic data to be used in this study.
*Reprint requests: Pierre Mansat, MD, PhD, Service d’Orthop? edie-
Traumatologie, Centre Hospitalier Universitaire de Toulouse Purpan, Place
du Dr Baylac, 31059 Toulouse, France.
E-mail address: firstname.lastname@example.org (P. Mansat).
J Shoulder Elbow Surg (2013) 22, 612-619
1058-2746/$ - see front matter ? 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.
implant was supposed to compensate for the wear of the
humeral head and restore the function of the rotator cuff
muscles. A radiographic study conduced by Thomas et al33
showed that the Copeland resurfacing shoulder arthroplasty
allowed restoration of normal anatomic parameters of the
humeral head. This study investigated the hypothesis that
the resurfacing humeral prosthesis restores the normal
glenohumeral relationships and correlates with the final
Materials and methods
This single-center continuous study was conducted from 2005 to
2009 in our department. The inclusion criteria were (1) all patients
follow-up. The exclusioncriteriawere (1) a rotator cuff rupture that
infection or neurologic complication, (4) bone stock insufficiency,
(5) and less than 2 years of follow-up. The Global C.A.P. resur-
facing implant was used (Depuy, Warsaw, IN, USA) in all cases.
During the study period, 61 patients (64 shoulders) fulfilled the
inclusion criteria and were monitored prospectively. The patients
(33 men and 28 women) were a mean age of 57 years (range, 30-80
years) at the time of the surgery. Preoperative diagnoses included
primary osteoarthritis in 26 shoulders, postinstability arthritis in 14,
post-traumatic arthritis in 7, avascular necrosis in 4, rheumatoid
arthritis in 4, dysplasia with degenerative lesions in 4, and other
indications in 5. Previous operations in 19 patients included the
Latarjet procedure in 7, cuff repair in 4, osteosynthesis of the
The indication for surgery was a painful shoulder with
limited function and degenerative changes at the glenohumeral
joint on radiographs. According to the Constant criteria,5pain
was the main symptom (4.1 ? 2.66 of 15 points). Range of
motion was limited, with an average active anterior elevation of
103?? 33?(range, 30?-170?), an average active lateral rotation
elbow at side of 10?? 19?(range, –45?to 70?), and an active
medial rotation (evaluated with the thumb on the spine) reaching
the sacrum (range, thigh-T10). On anterior-posterior views,
radiographic evaluation showed an almost centered humeral
head with an average acromiohumeral distance of 10 ? 4 mm
(range, 1-25 mm). According to the Walch et al classification,34
computed tomography (CT) scan analysis showed centered type
A glenoid wear in 45 shoulders, excentric-type B glenoid wear
in 14, and dysplastic type C glenoid in 5 shoulders with glenoid
retroversion greater than 25?. The Goutallier et al11classification
was used to evaluate the fatty degeneration index, which was
1 ? 0.98 for the supraspinatus, 0.98 ? 0.92 for the sub-
scapularis, and 1 ? 0.93 for the infraspinatus, with a global fatty
degeneration index of 1 ? 0.85 (Table I). An isolated supra-
spinatus tendon tear was found in 6 shoulders.
Preoperative planning was based on anterior-posterior and axillary
views of the shoulder and also on CT scan to specify humeral head
morphology, scapulometry, importance of wear, and muscular
trophicity. Templates were available to evaluate the size of the
humeral head preoperatively to adapt precisely the size of the
implant to the patient’s shoulder. All patients were operated on in
the beach chair position and under general anesthesia after an
interscalene block. The deltopectoral approach was used for all
A tenotomy of the subscapularis was made in 41 shoulders, and
a direct desinsertion of the tendon on the lesser tuberosity was
preferred in 23. After the humeral head was dislocated, bone
osteophytes were resected to better visualize the plane of the
anatomic neck and the superior insertion of the rotator cuff. A trial
allowed the surgeonto estimate the size of the humeral head. When
the estimate size was between two sizes, the smallest was chosen.
A guide, adapted to the size of the humeral head and placed
parallel to the plane of the anatomic neck, allowed localizing the
center of the humeral head. A Kirschner wire was positioned at the
center of the articular surface. It allowed adjusting automatically
the version, inclination, and offset of the prosthesis. A reamer
centered on the Kirschner wire prepared the humeral head to the
design and the size of the prosthesis. A trial of the prosthesis was
used to verify the adequate preparation of the humeral head. The
position of the central plot was prepared, and the humeral head
trial was impacted.
The arm was then positioned in abduction, neutral rotation, and
antepulsion. The subscapularis tendon was released anteriorly and
posteriorly from the neck of the scapula. The capsule was released
anteriorly and inferiorly. A Mehary retractor was positioned
between the humeral head and the glenoid, exposing the posterior
capsule. The posterior capsule was then released. A Fukuda
retractor or a Hohmann retractor was then used to push the
humeral head posteriorly. The glenoid surface was inspected. No
glenoid resurfacing was performed in this study, but an interpo-
sition was performed in 1 shoulder using the anterior capsule. No
other procedure was performed on the glenoid, even in excentric
glenoid wear. Then, the definitive implant was impacted.
Humeral head sizes were 40 mm for 9 shoulders, 44 mm for
11, 48 mm for 16, 52 mm for 15, and 56 mm for 13. The shoulder
was reduced and tested. The goal was to obtain 40?of external
rotation, 50% of translation of the humeral head on the glenoid,
and 60?of internal rotation of the arm at 90?of abduction.
The subscapularis tendon was repaired by tendon-to-tendon
sutures if a tenotomy had been made initially or with sutures
through bone if a desinsertion of the tendon had been made
directly over the lesser tuberosity. The supraspinatus tendon tear
was repaired in all cases. The biceps tendon was tenodesed in
26 shoulders and left intact in 38.
fatty degeneration index of the supraspinatus, infraspinatus,
and subscapularis muscles for the 64 shoulders included in this
Computed tomography evaluation of preoperative
)Muscles assessed according to the Goutallier et al11classification.
Resurfacing humeral prosthesis613
Patients were protected in a sling for 45 days. Passive motion was
allowed at day 2 after the drain was removed. Lateral rotation was
protected until 45 days; then, active motion was started in all
directions. Strengthening exercises were started at the end of the
third month postoperatively. Usually, 6 months of physiotherapy
was necessary, and then the patients were encouraged to continue
the exercises at home until the end of the first year after surgery.
All patients were monitored prospectively, clinically and radio-
graphically, at 3 and 6 months, 1 and 2 years, and at the last follow-
the Constant score,5and the Quick-Disabilities of Arm, Shoulder
and Hand (DASH) score.2Radiographic analysis was performed
using an anterior-posterior view in neutral rotation and an axillary
view. Anterior-posterior views were performed with the shoulder in
plane of the scapula. A magnification of 1 was always used.
Specific attention was given to analyze the correct position of
the implant in the frontal plane 3 months after surgery and at the
latest follow-up and to compare it with the preoperative values.
The center (C) of rotation of the humeral head was measured
with templates; then, the radius of curvature (RC) of the humeral
head, the humeral head height (HH), the humeral head diameter
(HD), and the inclination angle of the proximal humerus (CCD)
the distance of the center of the humeral head (C) from the central
axis of the humeral canal (A). The height of the center of rotation
(CG) was calculated by the distance sparing the center of rotation
(G). The deepness of the glenoid (GD) was also evaluated to
visualize narrowing of the joint line with follow-up (Fig. 1).
Measurements also consisted of evaluation of the acromio-
humeral distance (AHD), the distance between the tangent at the
top of the resurfacing implant and the tangent at the superior part
of the greater tuberosity (D), and the distance between the greater
tuberosity and the lateral projection of the acromion or lateral
offset (LO; Fig. 2).
Also analyzed were lucent lines around the resurfacing implant
and the possible migration of the prosthesis.
Data were analyzed with the use of statistical software that allowed
us to analyze each variable separately and to study their interrela-
tionships. Comparisons between different groups were performed
categoric values. The level of significance was set at P <.05.
At an average follow-up of 36 months (range, 24-65.6
months), the Constant score reached 68 ? 20 points (range,
29-100 points) and the Quick-DASH score reached 28 ?
21 points (range, 0-88 points). According to the Neer rating
score, results were very satisfactory in 28 shoulders, satis-
factory in 16, and nonsatisfactory in 20.
A, projection of the center of the humeral diaphysis; C, center of
the humeral head; CA, medial offset; CCD, inclination of the
humeral head; CG, center of rotation height; D, distance between
the upper most part of the humeral head and the upper part of the
greater tuberosity; GD, glenoid depth; HD, humeral diameter; HH,
humeral head height; RC, radius of curvature.
Method of radiographic analysis in the frontal plane.
AHD, acromiohumeral distance; CCD, inclination of the humeral
head; D, distance between the upper most part of the humeral head
and the upper part of the greater tuberosity; LO, lateral offset.
Method of radiographic analysis in the frontal plane.
614 P. Mansat et al.
The pain score improved to 11 ? 3.56 points
postoperatively, and 22 shoulders were totally pain free
(P <.01). However, pain in 11 shoulders was still moderate
or severe at follow-up. Activity level improved from 7 ? 3
points preoperatively to 15 ? 4 points postoperatively
(P < .01). Mobility improved from 17 ? 7 points preop-
eratively to 30 ? 8 points postoperatively (P <.01). Active
anterior elevation reached 135?? 33?(range, 80?-180?;
P < .01), active lateral rotation elbow at the side reached
37?? 17?(range, 0?-85?; P < .01), and active medial
rotation evaluated with the thumb on the spine reached
T12 (range, thigh-T7; P < .01). Strength improved from
3.2 ? 3 kg (range, 0-12 kg) preoperatively to 12 ? 7 kg
(range, 0-25 kg) postoperatively (P < .01).
The best results were obtained for primary osteoarthritis
and for postinstability arthritis. For post-traumatic arthritis,
results were less favorable, and the worst results were ob-
tained for rheumatoid arthritis and dysplasia (Table II).
Comparisons of preoperative and postoperative measure-
ments are reported in Table III.
Comparison of measurements preoperatively and at 3
The mean preoperative humeral head diameter of 51 ?
5 mm was decreased to 48 ? 5 mm by implantation of the
prosthesis (P < .01). Humeral head height also decreased,
from 21 ? 4 mm preoperatively to 19 ? 2 mm post-
operatively (P <.01). There was no change of the humeral
head radius of curvature, varying from 26 ? 2 mm
preoperatively to 24 ? 2 mm at 3 months (P > .05).
Humeral medial offset increased from 3.3 ? 3.5 mm
preoperatively to 6.4 ? 3 mm postoperatively (P < .01).
The height of the center of rotation of the humeral head
increased from 12 ? 7 mm preoperatively to 13.4 ? 6 mm
postoperatively, but this was not significant (P > .05).
There was a tendency for the implant to be in varus, with
a humeral shaft angle varying from 134?? 7?preopera-
tively to 122?? 11?postoperatively (P < .01). However,
the distance between the top of the greater tuberosity and
the top of the prosthesis was not significantly modified by
the prosthesis, increasing from 8 ? 3 to 8 ? 5 mm
(P > .05). The humeral head stayed centered, with an
acromiohumeral distance of 10.8 ? 4 mm preoperatively
and 10.3 ? 4 mm postoperatively (P > .05). Finally, the
lateral humeral offset increased from 6.8 ? 9 mm preop-
eratively to 10.4 ? 9 mm postoperatively (P < .05).
Comparison of postoperative measurements at 3
months and at the latest follow-up
No statistical difference was noted between radiographic
measurements at 3 months and at the latest follow-up,
except that the glenoid depth increased from 4.2 ? 1.4 to
4.9 ? 1.8 mm (P <.01). At the last follow-up, the joint line
was still visible in 34 shoulders (54%), whereas no joint
line could be seen in 30 (46%). No lucent line was visible
on the radiographic analysis except in 1 shoulder, where an
osteolysis was seen around the central peg, without sign of
evolution with follow-up. There was no sign of migration of
the resurfacing implant (Fig. 3).
No infection occurred in this series. Furthermore, no
humeral head fractures were observed during impaction of
the resurfacing implant. At follow-up, 11 shoulders (17%)
remained painful. Glenoid erosion was noted in all shoul-
ders, with no joint line visible on radiographic analysis.
One shoulder was diagnosed with a rerupture of the
supraspinatus tendon. A revision surgery was performed in
5 shoulders (8%) after a bone scan showed a specific
hyperfixation on the glenoid side without another location
of hyperfixation. A glenoid resurfacing with a cemented
glenoid implant was performed in 2 patients at 24 months
and 36 months after the initial procedure, while keeping the
resurfacing humeral prosthesis, with satisfactory results on
pain level at follow-up. Indication for the initial procedure
was inflammatory arthritis in 1 shoulder and primary
osteoarthritis in the other. The humeral head prosthesis was
revised to a reverse total shoulder arthroplasty in 2 shoul-
ders of 2 women (aged 62 and 77 years) with primary
osteoarthritis, at 30 months and 60 months after the initial
procedure. Glenoid wear was associated in these 2 shoul-
ders, with poor rotator cuff function. Finally, in a young
patient (aged 49 years) with primary osteoarthritis, the
humeral head prosthesis was revised to a pyrocarbon
‘‘snooker ball,’’ without glenoid resurfacing, at 60 months
after the initial procedure.
Painful shoulders at follow-up were correlated with sex
(9.7 ? 3 points in women; 12 ? 3.5 points in men; P <.01),
preoperative surgery before the resurfacing procedure
(9.3 ? 3.4 points with previous surgery vs 11.6 ? 3.4 points
without previous surgery; P < .02), preoperative Constant
score (<32 points was correlated with a pain score
<11 points at follow-up; P < .02), the global fatty
degeneration index (>1 was correlated with pain score
<11 points at follow-up; P < .05), the size of the humeral
prosthesis, with better results with the biggest sizes
(P < .02), the visibility of the joint line at follow-up
(P < .01), and the height of the center of rotation at
follow-up (P <.05). The inclination angle of the prosthesis
had no influence on the results at last follow-up (P > .05).
The presence of a supraspinatus tear at surgery had no
influence on pain at follow-up; however, it influenced the
postoperative Constant score (P < .05), strength in abduc-
tion (P < .05), Quick-DASH score (P < .02), the post-
operative acromiohumeral distance (P < .01), and the
lateral offset (P < .05). The final result was not influenced
by the status of the biceps tendon, whether tenodesed or left
intact, or the type of preoperative glenoid wear according to
Resurfacing humeral prosthesis615
the Walch classification. No other complications were
noted in this study.
Normal glenohumeral relationships were well described by
Iannotti et al15in 1992. Boileau et al3showed the great
variability of these dimensions between individuals and
underlined the great difficulty in restoring normal anatomy
during arthroplasty. However, accurate positioning of the
prosthetic humeral head is necessary to reproduce normal
glenohumeral kinematics and avoid damage to the rotator
cuff and impingement on the glenoid component or the
coracoacromial arch.4,8,16The goal of resurfacing shoulder
prostheses is to automatically reproduce the individual
anatomy of the humeral head (diameter, radius of curvature,
version) and the lateral offset of the proximal humerus while
preserving the bone stock.6A radiographic study by Thomas
et al33showed that the Copeland resurfacing shoulder
arthroplasty allowed restoration of the normal anatomic
parameter of the humeral head. More recently, Hammond
et al12demonstrated that the humeral resurfacing implant
was able to replicate the geometric center of the humerus
more closely than the third-generation hemiarthroplasty.
In our study, the postoperative radius of curvature of the
humeral head was 24 ? 2 mm, which were less than the
preoperative values but were close to the 24 ? 2.1 mm
results of Iannotti et al.15Other authors have published
similar results .26,30,33Restoring a radius of curvature close
to normal is essential because an excessive increase does
not increase lateral humeral offset but may induce over-
stuffing of the joint.7Similarly, the height of the humeral
head is of paramount importance. In our study, it varied
only from 21 ? 4 mm preoperatively to 19 ? 2 mm post-
operatively. In the Iannotti studym15the humeral height
was of 19 ? 2 mm, similar with the Roberston et al30
results using computed tomography. Harryman et al13
showed that an increase of the humeral height of 5 mm
or greater will induce a decrease of 20?to 30?of range of
motion. With the different sizes of the resurfacing pros-
theses available, reconstruction of the humeral head size
close to the normal anatomy seems reliable.
index, was 8 ? 5 mm, similar to the results presented
by Iannotti et al,15with 8 ? 3.2 mm in normal glenohumeral
joint. Positioning the resurfacing implant related to the top
of the greater tuberosity is fundamental to avoid impinge-
ment of the greater tuberosity under the acromion if it is
placed too low, or overstuffing the cuff tendons with limited
range of motion if it is placed too proud.16,23
Clinical results of the 64 resurfacing shoulder arthroplasties
(months) (years)(points)(deg)(deg) (points) (points)(points)
AAE, active anterior elevation; ALR, active lateral rotation; AMR, active medial rotation; AVN, avascular necrosis; PIA, postinstability arthritis;
POA, primary osteoarthritis; PTA, post-traumatic arthritis; RA, rheumatoid arthritis.
)Pain is scored according Constant criteria of 15 points.
Radiographic results of the 64 resurfacing shoulder
PreoperativeAt 3 months Latest follow-up
Mean ? SD
51 ? 5
21 ? 4
26 ? 2
3.33 ? 3.5
12 ? 7
134 ? 7
8 ? 3
10.8 ? 4
6.8 ? 9
Mean ? SD
48 ? 5)
19 ? 2)
24 ? 2
6.4 ? 3)
13.4 ? 7
122 ? 11)
8 ? 5
10.3 ? 4
10.4 ? 9y
4.2 ? 1.4
Mean ? SD
48 ? 5
19 ? 2
24 ? 2
6.5 ? 3
14 ? 7
120 ? 11
7.5 ? 4
10 ? 5
9.6 ? 9
4.9 ? 1.8)
AHD, acromiohumeral distance; CA, medial offset; CCD, humeral head
inclination; CG, height of the center of rotation; D, distance between
the upper most part of the humeral head and the upper most part of
the greater tuberosity; GD, glenoid depth; HD, humeral diameter; HH,
humeral height; LO, lateral offset; RC, radius of curvature; SD, standard
)P < 0.1.
yP < .05; results for all other variables were not significant.
616P. Mansat et al.
The height of the instantaneous center of rotation was
comparable preoperatively and postoperatively in our study.
In the Thomas et al33report, the center of rotation moved
superiorly but not significantly corresponding to accurate
centering of the prosthesis. Fischer et al9showed that if the
center of curvature is displaced by 20% of its radius, the
lever arm of the rotator cuff will be altered by 20%. The
absence of variation of this center suggests accurate
centering of the prosthesis on the retained head and neck.
In our series, however, the inclination angle was 122??
11?postoperatively compared with 134?? 7?preopera-
tively, corresponding to a tendency to position the pros-
thesis in varus. Some studies have even shown a wide range
of variation of this angle.3,14,15,25,30These results depend
directly on the surgical technique and show the difficulty of
implanting the prosthesis in a perfect position. The diffi-
culty in finding adequate landmarks on a pathologic
shoulder and the inaccuracy of the instruments available
can explain this malposition. The prosthesis must be placed
parallel to the anatomic neck of the humeral head and
superiorly at the insertion of the supraspinatus tendon on
the greater tuberosity, respecting the insertion facet of the
supraspinatus. In our series, however, the inclination of the
prosthesis had no influence on the clinical results at follow-
up, perhaps because it stays within the range of normal
Reconstruction of the lateral humeral offset is important
for optimization of the moment arm of the deltoid and
rotator cuff and of the normal tension of the soft tissue after
prosthetic reconstruction.15,28In our study, the humeral
offset, which has been defined by the distance of the center
of the humeral head from the central axis of the humeral
canal, or medial humeral offset, increased from 3.33 ?
3.5 mm preoperatively to 6.4 ? 3 mm postoperatively. This
distance varies from 4 to 14 mm in other reports.3,26,30
Similarly, the distance between the greater tuberosity and
the lateral projection of the acromion, or lateral humeral
offset, increased from 6.8 ? 9 mm preoperatively to 10.4 ?
9 mm postoperatively, corresponding to lateralization of the
humeral head. The resurfacing implant compensates for the
medialization of the humeral head secondary to the wear of
the joint surface, with the thickness of the implant allowing
restoration of the lever arm of the rotator cuff tendons.
Thomas et al33found that the Copeland resurfacing
shoulder arthroplasty increased humeral offset and the
deltoid and cuff lever arm by mean of 22% from the
pathologic state. Furthermore, in their population, medial-
ization of the humeral head because of wear was evaluated
to 6 mm and was compensated by the resurfacing shoulder
arthroplasty, allowing restoration postoperatively of a
lateral offset of 6 mm.
In our series, the resurfacing shoulder arthroplasty gave
satisfactory results, comparable to those that have already
been published.1,10,18-21,24,27,33,35However, with follow-up,
the resurfacing shoulder implant without glenoid resurfac-
ing leads to glenoid wear. This evolution was shown in our
study by the increase of the glenoid depth between the
immediate postoperative measures and the same measures
at the last follow-up (4.2 ? 1.4 v 4.9 ? 1.8 mm; P < .01).
No joint line was visible at follow-up in 30 shoulders (46%)
and was correlated with pain in 11 shoulders. In the
Thomas et al33study, the lateral offset compensating the
initial wear also seemed to decrease with follow-up by
a mean of 2 mm. Others studies have found the same
Anterior-posterior view of a shoulder with primary osteoarthritis (A) preoperatively and (B) at the last follow-up.
Resurfacing humeral prosthesis617
shoulder arthroplasty does not resolve the problem of the
long-term results of hemiarthroplasty, even it replicates the
anatomy of the proximal humerus close to normal.29,32As
for the stemmed anatomic prosthesis, associating a glenoid
implant with a resurfacing shoulder implant seems to be the
best option to avoid this evolution.24However, the indica-
tion must be discussed in young patients.
The resurfacing humeral prosthesis seemed to reproduce
anatomy that was close to the normal glenohumeral
joint. However, there was a tendency to place the
implant in varus, meaning that positioning of the pros-
thesis can be improved. The position of the prosthesis
did not vary with follow-up. However, as with hemi-
arthroplasties, there was a tendency for glenoid wear to
occur over time, leading to recurrence of pain and, in
some patients, to revision of the implant to a total
shoulder arthroplasty. The resurfacing shoulder implant
is a valuable therapeutic option to treat degenerative
shoulder diseases. Reliable results can be expected,
especially when the humeral head is centered and the
global fatty degeneration index of 1 or less.
The authors, their immediate families, and any research
foundations with which they are affiliated have not
received any financial payments or other benefits from
any commercial entity related to the subject of this
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