Keywords
McLaughlin's procedure - reverse Hill–Sachs lesion - posterior shoulder dislocation
- arthroscopy
Introduction
Posterior shoulder dislocations account for 2 to 5%[1]
[2]
[3] of all shoulder dislocations. They usually occur as a result of a high-energy trauma
associated with epileptic seizures or electrocution.[4]
[5]
[6] This type of injury is often underestimated at the initial patient's evaluation,
so that misdiagnosis might occur in 50 to 79% of all cases.[7]
[8] This could be a result of inadequate physical examination, misinterpretation of
plain radiographic films, or insufficient radiographic assessment. An average delay
of 23.6 months has been reported concerning the time span between the injury and its
precise diagnosis.[9]
Several treatment options have been described for the treatment of posterior shoulder
dislocation. These options range from neglecting it to total shoulder arthroplasty
depending on the functional status of the patient, the time elapsed between the injury
and the diagnosis, the concomitant glenoid, and humeral head bone defects.[10] There are still many controversies regarding surgical treatment, due to a lack of
understanding, the pathomechanical issues leading to posterior instability.[11] Traumatic posterior shoulder dislocations are often accompanied by a compression
fracture on the anterior surface of the humeral head known as a “reverse Hill–Sachs
lesion.” This bony defect can engage on the posterior glenoid rim and subsequently
lead to recurrent instability and progressive joint destruction.[12] Open or arthroscopic surgical procedures can be accomplished to address humeral
head defects and to restore joint stability. These operative techniques can be divided
into nonanatomic and anatomic procedures.[13] Regarding the open nonanatomic techniques, McLaughlin was the first to describe
the reconstruction of the humeral bone defect, caused by posterior shoulder dislocation,
with the transfer of subscapularis tendon insertion into the lesion.[14] Different techniques to perform this procedure arthroscopically have been described
in technical notes.[12]
[15]
[16]
[17]
Therefore, we conducted a clinical study to assess the clinical and functional outcome
of the arthroscopic McLaughlin procedure for the treatment of patients suffering from
locked posterior shoulder dislocation combined with reverse Hill–Sachs lesion. Our
hypothesis was that this nonanatomic arthroscopic technique would be proven safe and
efficient even in the treatment of large humeral bone defects.
Methods
This is a retrospective cohort study using prospectively collected data regarding
the clinical and functional outcomes of patients with locked posterior shoulder dislocation
who underwent an all-arthroscopic McLaughlin's procedure. These patients were treated
in our department from January 2009 to December 2012. The main issues addressed in
this study are the effect of this management (1) on the recurrence rate, (2) on the
shoulder mobility, and (3) on the patients' function. The ability to return to the
preinjury level of everyday and sporting activities is also examined. Approval was
obtained from the Institutional Review Board (IRB) of our Hospital (ID number: 96/2013)
according to the official guidelines of the Declaration of Helsinki. Informed consent
was obtained from all the individual participants included in the study
Participants
Patients included in the study met the following eligibility criteria: (1) clinically
and radiologically confirmed diagnosis of neglected unreduced traumatic posterior
shoulder dislocation, (2) a bony defect >20% of the humeral head based on the preoperative
computed tomography (CT), (3) treatment with all-arthroscopic McLaughlin's procedure,
and (4) at least 5 years of postoperative follow-up. We excluded all patients who
had an acute and nonlocked posterior shoulder dislocation, patients with nontraumatic
posterior shoulder dislocation, recurrent posterior shoulder dislocation, multidirectional
shoulder instability, psychiatric patients, epileptic patients, patients suffering
by systematic diseases, patients with substantial glenoid bone loss, and patients
with previous shoulder surgery. In addition, we did not include in our study patients
with a reverse Hill–Sachs lesion <20% of the diameter of the affected humeral head,
those with irreducible dislocation with closed method, those who were not treated
with an all-arthroscopic modified McLaughlin's procedure and all those who had postoperative
follow-up less than 60 months.
All patients of this group had been involved in motor vehicle accident. These patients
had been initially treated elsewhere with conservative means, as a result of a misdiagnosis.
They suffered by mild-to-moderate pain which required oral analgesics. No patient
had any neurological defect as result of their injury. The interval between the traumatic
event and the operation was 2.7 months (range, 2 weeks–10 months).
Intervention
The operation was performed in lateral decubitus position, under interscalene brachial
plexus block, in addition to general anesthesia with laryngeal mask and spontaneous
breathing. Closed reduction was initially performed followed by standard shoulder
arthroscopy. The cases that did not achieve closed reduction were excluded from this
study. The degree of the glenoid bone loss was identified intraoperatively using a
calibrated probe for measuring the anterior and the posterior radii of the inferior
glenoid at the level of the bare spot. Bone loss was quantified as a percentage of
the normal inferior glenoid diameter (assumed to be twice the anterior radius). Reverse
Hill–Sachs lesions were also evaluated to confirm the preoperative CT assessment.
The tear of the posterior labrum was arthroscopically recognized, and a double-loaded
absorbable anchor (Lupine, DePuy Synthes, Raynham, MA) was mostly used, inserted by
the Port of Wilmington portal. The sutures of this anchor were passed through the
capsule and labrum without being tied. The reverse Hill–Sachs lesion was then abraded
with a burr, while one or two double-loaded anchors (depending on the size of the
defect) were inserted in the lesion. The insertion was achieved through an anterior
accessory portal made under direct supervision with the aid of a spinal needle. With
the use of a suitable “suture passing” instrument (usually a Bird Beak, Arthrex, Naples,
FL), the sutures were passed through the subscapularis tendon in a mattress fashion
and tied over the lesion bringing the tendon in firm contact with the abraded surface
of the humeral head. The knots were tied without passing the scope in the subacromial
space. After confirming the adequate filling of the humeral head defect, the repair
of the posterior complex was continued by tying the knots of the already inserted
suture anchor and, finally, by implanting additional anchors as required (usually
three double loaded anchors in total).
The operated shoulder was protected for 6 weeks in a brace of 30 degrees abduction
and neutral rotation. The patient was allowed to remove the sling for exercising.
Pendulum exercises, as well as elbow, and wrist range of motion (ROM) exercises were
encouraged three times per day. Activities of daily living were allowed after the
first few days as long as the motion of the shoulder was restricted to 90 degrees
of forward flexion, 30 degrees of external rotation (ER), and no internal rotation.
Active assisted exercises were started during the third postoperative week by gradual
increase of the ROM. Until the eighth week, the program was focused on the recovery
of glenohumeral ROM and the restoration of the scapular stability. Strengthening exercises
of the shoulder were started at approximately 8 weeks postoperatively, whereas special
attention was given to regain full ROM and dynamic stability of the joint. Overhead
activities were allowed after 3 months and contact sports after 6 to 9 months postoperatively,
depending on the progress of rehabilitation and the level of participation.
Outcome Measurements
A shoulder physical examination was performed preoperatively and in every follow-up
visit. The range of motion of the shoulder was measured with a goniometer. Shoulder
function was evaluated by the UCLA score and the Oxford instability score in every
follow-up visit. The patients were postoperatively examined at 3 and 6 weeks, and
then at 3, 6, 9, and 12 months, and every following year. Redislocation, subluxation,
or a positive apprehension sign after surgery was defined as failure of the treatment.
Any residual pain or other complaints were documented. Medical Research Council grading
system was used for evaluating the muscle strength.[18] This method involves testing the muscles against the examiner's resistance and grading
the patient's strength on a 0 to 5 scale accordingly (0 = no muscle activation; 1 = trace
muscle activation, without achieving full range of motion; 2 = muscle activation with
gravity eliminated, achieving full range of motion; 3 = muscle activation against
gravity; 4 = muscle activation against some resistance; 5 = muscle activation against
examiner's full resistance).
Since all patients had already undergone a standard radiographic evaluation, usually
with anteroposterior (AP) view, a CT scan ([Fig. 1]) was performed to confirm diagnosis and measure the bony defect of the humeral head.
The impression fracture was measured on the CT at the greatest diameter of the head
and was expressed as the percentage of the projected total articular surface.[19] A three-dimensional (3D) reconstruction was also used ([Fig. 2]).
Fig. 1 Images from preoperative CT scan showing the posterior dislocation of the humeral
head. The “locking” of the humeral head in the glenoid is depicted. CT, computed tomography.
Fig. 2 Images from preoperative 3D CT scan showing the posterior dislocation from different
views. 3D, three-dimensional; CT, computed tomography.
Data Analysis
Due to the small sample size, the distribution of the data analyzed did not meet the
assumption of normality. Thus all the variables, either continuous (shoulder ROM apart
from ER) or discrete (ER) or asymmetrical (functional tests), were reported as the
arithmetic mean and 1 standard deviation, while discrete variables as the arithmetic
median and ranging. The Wilcoxon's matched-pairs signed rank test was used to evaluate
the differences between the preoperative and postoperative ROMs and functional scores.
For all analyses, p < 0.05 was considered to be statistically significant.
Results
A total of 10 patients met the inclusion criteria of this study. The demographic characteristics
of these patients are depicted in [Table 1]. All patients were males with a mean age of 49.8 ± 12.1 years (range, 29–73 years).
Five shoulders (50%) were right and five (50%) were left. The dominant side was involved
in eight patients (80%). Eight patients (80%) were involved in sporting activities;
two were amateur athletes and six were recreational athletes. No professional athlete
was involved in this study group. No patient lost to follow-up. The average follow-up
was 77 ± 16 months (range, 63–104 months).
Table 1
Demographic characteristics of the patients included in the study
|
Number of patients included
|
n = 10
|
|
Age
(years)
|
49,8 ± 12.1 (range, 29–73)
|
|
Gender
Male
Female
|
10 (100%)
0 (0%)
|
|
Side
Left
Right
|
5 (50%)
5 (50%)
|
|
Dominant arm involved
|
8 (80%
|
|
Time interval between the injury and the operation (months)
|
2.7 (range, 0.5–10)
|
|
Sport participation
Amateur
Recreational
|
8 (80%)
2 (25%)
6 (75%)
|
|
Size of humeral bone defect
(% of the projected articular surface)
|
39 ± 7
|
A shoulder physical examination was performed preoperatively by two experienced shoulder
surgeons of our department. The total of the patients was found with an ER restriction
(ER = 0 degrees). The active forward flexion (FF) was slightly reduced in four patients
(FF > 160 degrees), significantly in two patients (160 > FF > 120 degrees), while
four patients had major restriction with FF = 60 degrees. Active internal rotation
(IR) was at the level of buttock, ranging from lateral thigh to T12.
The average humeral bone defect (reverse Hill–Sachs lesion) measured on preoperative
CT scan was equal to 39 ± 7%. No concomitant fractures of the surgical neck or the
lesser tuberosity were identified with the CT, while no signs of glenohumeral arthritis
were found in our patients.
A small supraspinatus tear was found in a single patient (10% of our sample) and was
arthroscopically repaired. No patient included in this study had a glenoid bone loss
>7%.
No patient suffered a new dislocation, whereas all patients (100%) were satisfied
with the surgical outcome and they returned to their previous activities of daily
living. No patient developed stiffness.
The ROM of the shoulder is shown in [Table 2]. Every patient participated in this study had full ER restriction (ER = 0 degrees)
at the baseline. ER had been restored to each one of them at the last follow-up, since
the median ER beside the body was 90 degrees (range, 50–90 degrees; p < 0.01) and the respective measurement at 90 degrees of abduction was 90 degrees
(range, 80–90 degree p < 0.01). The median active forward flexion was increased (p < 0.01) from 60 degrees (range, 30–180 degrees) preoperatively to 180 degrees (range,
160–180 degrees) at the last follow-up. The median internal rotation was gained (p < 0.01) from the level of buttock (range, lateral thigh–T12) preoperatively to the
T11 level (range, T7–L3) at the last follow-up ([Fig. 3]).
Fig. 3 Comparison of preoperative and postoperative range of motion. Pre-op, preoperative;
Post-op, postoperative.
Table 2
Comparison of shoulder range of motion and function between preoperative measurements
and values at the latest follow-up
|
Parameter
|
Preoperative
median (range)
|
Latest follow-up
median (range)
|
p-Value
|
|
Forward flexion
|
60 degrees (30–180)
|
180 degrees (160–180)
|
<0.01
|
|
External rotation beside the body
|
0 degrees (0–0)
|
90 degrees (50–90)
|
<0.01
|
|
External rotation at 90 degrees of abduction
|
0 degrees (0–0)
|
90 degrees (80–90)
|
<0.01
|
|
Internal rotation
|
Buttock (lateral thigh–T12)
|
T11 (T7–L3)
|
<0.01
|
|
UCLA score
|
8 (4–22)
|
35 (33–35)
|
<0.01
|
|
Oxford instability score
|
5 (3–16)
|
46 (43–48)
|
<0.01
|
Both the mean UCLA score and the Oxford instability score were significantly increased.
The median UCLA score was increased from 8 (range, 4–22) preoperatively to 35 (range,
33–35) at the last follow-up (p < 0.01). Respectively, the mean Oxford instability score was increased from 5 (range,
3–16) preoperatively to 46 (range, 43–48) at the last follow-up (p < 0.01; [Fig. 4]). The strength measured in forward flexion, abduction, ER, and internal rotation
of the shoulder was normal (grade 5) for every patient at the last follow-up.
Fig. 4 Comparison of preoperative and postoperative functional outcomes. Pre-op, preoperative;
Post-op, postoperative.
Discussion
The most important finding of the present study is the excellent clinical and functional
outcome with the use of all-arthroscopic McLaughlin's procedure for patients suffering
by locked posterior shoulder dislocation combined with substantial humeral head bone
loss. Our case series presents the clinical outcomes regarding the arthroscopic repair
of reverse Hill–Sachs lesion in patients with locked posterior shoulder dislocation.
Despite the technical notes that had been published,[15]
[18]
[20]
[21]
[22] this arthroscopic technique had yet not been clinically evaluated.
According to a systematic review, the management of posterior shoulder dislocation
should be individualized for each patient based on the time of initial diagnosis,
the size of the reverse Hill–Sachs lesion, and the associated injuries.[10] The size of the impression fracture of the humeral head usually defines the treatment
modality.[20] The management of anteromedial defects remains challenging, especially considering
defects between 25 and 40% of the articular surface which require a detailed preoperative
planning. The development of advanced imaging modalities, such as the CT scanning
with 3D reconstruction, allowed better assessment of the humeral head bone loss.[19]
A variety of operations have been proposed as possible solutions for the treatment
of these complex injuries. Various surgical approaches have been reported including
arthroscopic repair, open nonanatomical muscle/tendon transfers,[9]
[12]
[21]
[22] rotational osteotomies of the proximal humerus,[23] anatomical bone grafting,[24]
[25]
[26]
[27] and shoulder arthroplasty.[28] The proposed arthroscopic techniques to address posterior shoulder dislocation include
the repair of the posterior Bankart's lesion in combination with a capsular shift.[12] However, in cases of substantial reverse Hill–Sachs lesions, the surgeon should
also address the humeral head bony defects. At the middle of the previous century,
McLaughlin[14] was the first surgeon to recognize the significance of the impression fracture of
the humeral head as for the treatment of chronic posterior dislocation of the shoulder.
Neer[29] modified the McLaughlin subscapularis transposition and transferred the lesser tuberosity
with its attached subscapularis tendon en bloc to the defect.
There are only very few studies in the recent literature describing the nonanatomic
operative treatment of chronic locked posterior dislocation of the shoulder. Shams
et al evaluated the clinical outcome of open modified McLaughlin's procedure in 11
patients with locked chronic posterior shoulder dislocation and reverse Hill–Sachs
defects.[30] They concluded that reconstructing the reverse Hill–Sachs defect provides adequate
stability, pain relief, and function in patients with locked chronic posterior shoulder
dislocation, and a defect involving 25 to 50% of the humeral head. In another study,
Demirel et al investigated the middle-term functional and radiological outcomes of
the transfer of the lesser tuberosity in the management of reverse Hill–Sachs lesions
following posterior dislocations of the shoulder.[31] They reported satisfactory results at the last follow-up of 13 patients treated
in an open manner. In a case report of a young male athlete with neglected locked
posterior shoulder dislocation combined with reverse Hill–Sachs lesion, Steckel et
al illustrated excellent clinical, functional, and radiological outcome after open
modified McLaughlin's procedure[32] Finally, in another case report, Charalambous et al described a modification of
the open repair through deltopectoral approach and plication of the subscapularis
tendon into the reverse Hill–Sachs lesion via two-bone anchors.[21] The McLaughlin procedure was described to be performed arthroscopically[16] with the use of suture anchors for fixing subscapularis tendon into the humeral
bony defect. However, we found only level-V papers published (without any clinical
outcome) regarding this arthroscopic modified McLaughlin's procedure.[12]
[15]
[16]
[17] The present study is the first to investigate the clinical and functional results
of the arthroscopic modified McLaughlin procedure. Particularly, all the clinical
subjective scores (UCLA and Oxford instability score) used for the follow-up assessment
of our patients were found statistically improved. Even more, the ROM of the shoulder
was restored to normal to every patient participated in this study. Apart from that,
it should be emphasized that there was no recurrence of instability in our series.
This was possibly the result of the meticulous preoperative planning, the cautious
reduction maneuvers, and the detailed arthroscopic evaluation. During the operation,
special attention was given to suture the subscapularis tendon in the humeral head
defect to close the gap, repair the posterior labral lesions, plicate the capsule
(when it was considered necessary), and treat any other identified lesion. Special
care was also taken in relation to the postoperative rehabilitation program, which
should allow the soft tissue healing without any tension and discourage aggressive
mobilization that might provoke recurrence of the instability.
Limitations
This study is not without limitations. Weak points were the retrospective design and
the small number of patients. On the other hand, the data that we used were prospectively
collected, whereas the rarity of this clinical entity justified the observational
study design. Regarding the scarcity of patients with neglected locked posterior shoulder
dislocation, the number of patients involved in our trial should be considered acceptable.
Conclusion
In conclusion, the arthroscopic McLaughlin procedure in substantial reverse Hills-Sachs
lesion caused by locked posterior dislocation leads to excellent clinical and functional
results in the long-term follow-up.
