Humeral head replacement has historically been favored over total shoulder arthroplasty for the management of specific shoulder conditions such as humeral head osteonecrosis with an intact glenoid cartilaginous surface, cuff tear arthropathy with fixed upward displacement of the humeral head, complex proximal humeral fractures in the elderly, and glenohumeral arthritis in young patients who have had failure of nonoperative measures1-4.
In a recent review of thirty-three studies (2540 shoulders) pertaining to unconstrained total shoulder arthroplasty, glenoid component loosening accounted for 39% of all complications5. Persistent concerns regarding the long-term durability of polyethylene glenoid prostheses in terms of wear and loosening have prompted many surgeons to favor humeral hemiarthroplasty in young patients with glenohumeral arthritis, even though clinical outcome studies and meta-analyses have indicated that, overall, total shoulder arthroplasty provides better results than humeral head replacement alone with regard to pain relief, motion, and level of activity6-9.
Despite good early and midterm results with hemiarthroplasty, progressive glenoid erosion and painful glenoid arthritis are the most common reasons for failure and the need for reoperation7,10,11. Moreover, the results of conversion of a hemiarthroplasty to a total shoulder replacement have proven to be less predictable than those of primary total shoulder arthroplasty secondary to limited range of motion, with unpredictable improvement in pain, and the more frequent need for subsequent operations12,13.
In an effort to minimize the complications of painful glenoid arthritis and glenoid erosion associated with hemiarthroplasty and glenoid component failure associated with total shoulder arthroplasty, the proponents of the use of hemiarthroplasty in younger patients (less than sixty years of age) have explored adjunctive biological glenoid resurfacing with use of the anterior glenohumeral capsule, autogenous fascia lata, Achilles tendon allograft, and meniscal allograft14-17.
The purposes of this report were (1) to describe a technique that was developed to facilitate biological resurfacing of the glenoid with use of meniscal allograft tissue and (2) to report the effectiveness of hemiarthroplasty in conjunction with meniscal allograft glenoid resurfacing in patients who were fifty-three years of age or less.
All patients who were to have a shoulder arthroplasty between September 2001 and September 2006 were evaluated for inclusion in this study. The arthroplasties were performed with a DePuy Global Shoulder modular prosthesis (DePuy, a Johnson and Johnson company, Warsaw, Indiana). The inclusion criteria for the study were a diagnosis of glenohumeral arthritis that limited the activities of daily living combined with pain in the shoulder that was refractory to conservative measures, and patients who were fifty-five years of age or less, had a failure of nonoperative treatment (including anti-inflammatory medication, activity modification, vocational rehabilitation, and analgesics) for a minimum of twelve months, and had requested surgical intervention. The upper age limit of fifty-five years was arbitrarily established as a criterion of the study methodology and was based on personal and historical perspective. A combination of the history, radiographic studies, and previous operative findings was used to establish the diagnosis of arthritis involving both the humeral head and the glenoid. Lastly, inclusion criteria required that, at the time of the operation, the glenoid demonstrate findings indicative of arthropathy. These findings included degeneration of the articular cartilage, eccentric glenoid wear, glenoid erosion, and loss of articular cartilage with flattening of the osseous surface.
Clinical assessments were performed preoperatively and at one-year intervals postoperatively for at least two years. Active range-of-motion variables, including elevation, external rotation, and internal rotation, were measured. Active elevation and external rotation (with the arm adducted) were measured by the examiner with a 2-ft (61-cm)-long handheld goniometer and were recorded in 5° increments. Internal rotation was recorded as the highest vertebral level that the patient could reach with the thumb extended.
Outcome data were derived from patient self-assessment instruments, including the American Shoulder and Elbow Surgeons (ASES) questionnaire (an overall shoulder scoring system based on ten questions concerning the functional activities of daily living, pain, and patient satisfaction), and the Simple Shoulder Test (SST)18,19. Visual analog scales were used preoperatively and postoperatively to evaluate the following four parameters: (1) pain at rest, (2) pain level on an average day, (3) pain with strenuous activities, and (4) shoulder stability. For these scales, the patients were asked to place a mark on a 10-cm line, which was later measured to the nearest millimeter and was recorded as a score from 0 to 100 (with zero reflecting a pain-free or problem-free response).
Thirty consecutive patients (thirty shoulders) were enrolled in the study, and twenty-seven of them were followed for a minimum of two years according to the study protocol. Twenty-five patients returned for clinical and radiographic examination at regular intervals. Two patients returned self-assessment forms and had a local orthopaedic surgeon send the results of a clinical examination and recent radiographs. Clinical assessment and outcome data on patients undergoing additional surgery were obtained within a two-week period prior to reoperation and were included in the analysis. The mean duration of follow-up was three years (range, two to five years). Three additional patients met the inclusion criteria, but two were lost to follow-up and one chose not to participate in the study.
The study group included eight women and nineteen men with an average age of forty-three years (range, twenty-four to fifty-three years). Seventeen of the twenty-seven shoulders were on the dominant side. The diagnoses included the sequelae of trauma (eleven shoulders), osteoarthritis (eleven), capsulorrhaphy arthropathy secondary to surgery for recurrent instability (three), juvenile rheumatoid arthritis (one), and osteonecrosis (one).
Fifteen of the twenty-seven shoulders had had a previous procedure. Six shoulders had had one procedure; five shoulders, two procedures; one shoulder, three procedures; two shoulders, four procedures; and one shoulder, five procedures. Previous operations included arthroscopic exploration and/or débridement (six shoulders), anterior capsulorrhaphy (five), open reduction and internal fixation of a fracture (three), rotator cuff repair (three), posterior capsulorrhaphy (two), a Bristow procedure (one), a Putti-Platt procedure (one), open débridement (one), acromioplasty (one), and a hemiarthroplasty for fracture (one).
The patients were categorized into one of five physical demand levels according to the estimated overall strength requirements of their occupation as defined by the U.S. Department of Labor20. Eleven patients were employed in occupations involving heavy to very heavy physical demands, including oil field work (three patients), construction (two), ranching (two), firefighting (one), active-duty military service (one), automobile mechanical work (one), and meat cutting (one). Seven patients were employed at occupations involving light-to-medium demand levels. Of the remaining nine patients, one was unemployed and eight were employed in occupations involving sedentary demands.
As a precautionary measure to ensure patient confidentiality, each patient was assigned a specific identification number. The names and identification numbers were kept separately, so that the analysis of the data was performed without knowledge of the identity of the patients. The risks and benefits of operative treatment, including the risk of allograft-associated infection, were discussed in detail. All patients in the study provided full verbal and written consent for operative treatment and participation in this study. Our institutional review board approved the study.
Radiographic Analysis
An axillary lateral radiograph and an anteroposterior radiograph, made perpendicular to the plane of the scapula with the humerus externally rotated 30°, were made for all patients. The radiographic analysis included assessment of glenohumeral subluxation, glenoid erosion, and the glenohumeral joint space. Glenohumeral subluxation was evaluated on the preoperative and final postoperative axillary lateral radiograph with respect to the direction and amount of translation of the center of the humeral head relative to the center of the glenoid according to the method of Iannotti and Norris21. The center of the humeral head was determined with use of concentric best-fit circles. The center point between the anterior and posterior aspects of the glenoid rim was marked on a line perpendicular to the scapular body. The distance from the center of the humeral head to the center of the glenoid was measured and divided by the diameter of the head. The humeral head was considered to be centered in the glenoid if the distance between the center of the humeral head and the center of the glenoid was <25% of the humeral head diameter, moderately subluxated if it was between 25% and 50%, and severely subluxated if it was >50%. The glenohumeral joint space was measured on the preoperative, immediate postoperative, and final postoperative axillary lateral radiographs in millimeters (Figs. 1-A and 1-B). Glenoid erosion was measured on both the preoperative and final postoperative axillary radiographs according to the method of Iannotti and Norris21. This was accomplished by drawing a straight line parallel to the scapular body. A line perpendicular to this line was drawn from the anterior glenoid margin, and the amount of bone from the posterior edge of the glenoid to the perpendicular line was measured in millimeters. Mild glenoid bone loss was considered to be <5 mm; moderate loss, between 5 and 10 mm; and severe loss, >10 mm.
Statistical Analysis
The significance of the effect of surgery was assessed with use of the Wilcoxon signed-rank test on subject changes (the postoperative value minus the preoperative value). All statistical testing was two-sided with a significance level of 5%.
Operative Technique
The technique of humeral prosthetic arthroplasty, including subscapularis mobilization, capsular release, and humeral head resection, has been described in detail previously1,22,23.
Glenoid Preparation and Meniscal Allograft Implantation
A glenoid that was nonconcentric and/or eroded was precisely contoured with a reamer to normalize glenoid version with respect to the scapula and to provide a concentric glenoid articular surface for optimal graft fixation and load transfer. The orientation of the reamer was facilitated by palpating the lateral extent of the subscapularis fossa at a point midway between the superior and lateral borders of the scapula. This point is described as the "centering point," and a line connecting this point to the center of the glenoid face is the normalized glenoid centerline1. Orienting the reamer to the normalized glenoid centerline enables the surgeon to improve pathologic glenoid version. When the glenoid was not reamed, or if no punctate bleeding was noted following reaming, a 1.5-mm drill was used to perforate the subchondral bone 5 to 6 mm medial to the glenoid rim, multiple times around the circumference of the glenoid articular surface. This was followed by an estimation of the prepared glenoid articular surface circumference. The determination was based on a set of trial glenoid components (available in five sizes) used for total shoulder arthroplasty. Next, the anterior and posterior horns of the lateral meniscal allograft (Musculoskeletal Transplant Foundation, Holmdel, New Jersey) were sutured together with number-2 Cottony Dacron suture (Deknatel, Fall River, Massachusetts), converting the meniscus into an oval structure which approximated the circumference of the selected trial glenoid component (Fig. 2).
The technique for glenoid suture placement was analogous to the method employed for mitral valve replacement in cardiothoracic surgery24. Initially, three commissural or segmenting sutures were placed through the glenoid labrum with use of number-2 Cottony Dacron. Next, additional sutures were placed in each of the three zones until there was a total of nine equilateral anchoring sites around the perimeter of the glenoid articular surface (Fig. 3). If a portion of the labral tissue was absent, 2.9-mm bioabsorbable suture anchors with a number-2 Durabraid suture (Smith and Nephew, Andover, Massachusetts) were used to secure the meniscal allograft at the site of deficiency. After placement of the anchoring sutures, the meniscal graft was temporarily positioned on the articular surface of the glenoid and a surgical marking pen was used to mark the border of the graft, which was adjacent to each of the nine suture anchoring sites (Fig. 4). Next, three Gabbay-Frater suture guides (Deknatel) were placed in a triangular configuration around the surgical field. The meniscal graft was repositioned above the wound by an assistant, who placed it in an easily accessible location for suturing, and one limb of each anchoring suture was passed through the meniscal allograft at the corresponding, previously marked site. After the sutures were passed through the graft, both limbs of the suture were secured in the suture guide (Fig. 5). When all sutures had been passed through the graft, the meniscus was slid down to the glenoid articular surface while tension was maintained on the sutures by pulling them through the guide as needed. Finally, the meniscus was secured by tying one anchoring suture from each of the three zones in a sequential fashion until all sutures had been tied (Figs. 6-A and 6-B).
Assessment of Soft-Tissue Balancing
Periarticular osteophytes were removed from both sides of the shoulder joint, and an anatomically sized trial humeral component was seated in place. Soft-tissue balancing was judged to be optimal when the following criteria were met: (1) posterior drawer testing demonstrated 40% to 60% translation of the center of the prosthetic head relative to the center of the glenoid, (2) =75° of internal rotation was present with the arm positioned in 90° of abduction, (3) the hand on the involved side could be placed on the superior aspect of the contralateral shoulder without protraction of the scapula, and (4) there was 45° of external rotation with the subscapularis approximated to the proximal humeral osteotomy site.
Postoperative Protocol
A physician-directed postoperative rehabilitation program was used for all patients. On the afternoon of the day of surgery, the physician performed passive forward flexion of the arm up to 90°, or as far as was comfortable, for each patient. On the first postoperative day, the patient performed active-assisted elevation with a pulley attached to an overhead frame, passive external rotation with a meter stick, and pendulum exercises. Each exercise involved five repetitions and was performed three to four times a day, seven days a week. The patient was encouraged to use the arm for gentle activities of daily living and was usually discharged on the second postoperative day. If the shoulder did not have sufficient passive motion by four to six weeks after surgery, additional stretching exercises were prescribed. If weakness of the deltoid was encountered, a specific exercise program with the patient in the supine position was instituted. The strengthening phase of this program was added after the shoulder had achieved a sufficient passive range of motion (120° to 140° of flexion and 20° to 40° of external rotation). This occurred typically by six to eight weeks after surgery. Additionally, the patient performed resisted shoulder shrug exercises for the trapezius. The serratus anterior and rhomboids were strengthened in all patients with the use of wall push-ups; in male patients, the wall push-ups were progressed to knee push-ups as symptoms allowed. The stretching exercises were continued throughout the rehabilitation and were decreased to one or two times a week in a maintenance program phase at four to six months after surgery.
Source of Funding
There was no external funding source for this study.
Clinical Findings
All patients reported substantial pain and functional limitations preoperatively. At a mean follow-up interval of thirty-five months, there was improvement both in the pain score and in the shoulder range of motion. The mean active forward elevation improved from 84° (range, 20° to 160°) preoperatively to 123° (range, 45° to 165°) at the final follow-up examination (p < 0.001). External rotation improved from a mean of 9° (range, -50° to 45°) to a mean of 39° (range, 0° to 60°) (p < 0.001). Internal rotation, measured as the highest vertebral level that the patient could reach with the thumb extended, improved a mean of two spinal segments (the preoperative range was from the lateral aspect of the hip to T10, and the postoperative range was from the hip to T9) (Table I).
The mean score on the ASES system improved from 30 points (range, 10 to 58 points) preoperatively to 67 points (range, 20 to 100 points) at the final follow-up examination. All ten measures of functional status showed significant improvement (Table II). The SST had a mean of 7.3 positive responses at the time of the final follow-up, which was a significant improvement from the mean of 2.7 positive responses preoperatively (p < 0.001). There was also significant improvement in the visual analog scale scores at the time of the most recent follow-up compared with the preoperative values. The visual analog scale score for stability changed from a mean of 44 points preoperatively to a mean of 26 points at the time of follow-up, which was an improvement of 18 points (p = 0.01). The mean score for pain improved from 67 points preoperatively to 26 points at the time of follow-up (p < 0.001) (Table III).
All patients returned to their preoperative employment status, and there was a notable improvement in sports-related activities. Preoperatively, fifteen patients were unable to participate in sports, eight found it very difficult, and four described their activity as somewhat difficult. Postoperatively, seven patients were unable to participate, four described sports activity as very difficult, ten reported that the activity was somewhat difficult, and six found that it was not difficult.
Radiographic Findings
Preoperatively, all patients demonstrated periarticular sclerosis, periarticular subchondral cysts, and humeral head osteophytes. Additionally, among the twenty-seven shoulders, fifteen (56%) had no subluxation, eleven (41%) had moderate subluxation, and one had severe subluxation. Postoperatively, the results had improved, with twenty-six shoulders having no subluxation and one having moderate subluxation. The preoperative glenohumeral joint space measured 1 mm in four shoulders and 0 mm (bone-on-bone findings) in twenty-three. The initial postoperative radiographs revealed a mean glenohumeral joint space of 3.5 mm (range, 1 to 5 mm) compared with a mean of 1.7 mm (range, 0 to 3 mm) at the most recent follow-up (Fig. 7). This decrease in the mean glenohumeral joint space was significant (p < 0.001). Preoperatively, glenoid erosion (which was manifested as a nonconcentric glenoid or a glenoid with increased retroversion due to eccentric posterior erosion) was noted in nineteen shoulders (70%). The erosion was graded as mild in thirteen shoulders and as moderate in six. Comparison of the immediate postoperative and most recent axillary lateral radiographs with respect to glenoid erosion revealed no glenoid bone loss for twenty-seven shoulders that had been followed for a mean of three years.
Complications and Reoperations
There were three complications in three shoulders, necessitating a reoperation in each shoulder. One patient with a history of open reduction and internal fixation for a proximal humeral fracture had a superficial infection develop ten days following surgery. The patient was successfully managed with superficial wound débridement and forty-eight hours of intravenous antibiotics. The second patient had shoulder discomfort when he returned to ranch work, against medical advice, at six weeks following surgery. The discomfort gradually increased over several months despite activity modification. At the time of reoperation, fourteen months after the index procedure, the lateral meniscal allograft was noted to be displaced from the glenoid articular surface. The graft was excised, and the glenoid was revised to a minimally cemented, polyethylene glenoid component. The last patient had four previous operations including three anterior capsular reconstruction procedures and open reduction and internal fixation of a proximal humeral fracture. At six weeks following surgery, the patient returned with swelling about the incision and a low-grade fever. Laboratory tests revealed a mildly elevated C-reactive protein level and erythrocyte sedimentation rate and a normal white blood-cell count. Tissue cultures at the time of operative débridement were positive for methicillin-resistant Staphylococcus aureus. During the course of hospitalization, the patient was presented with multiple treatment options, including two-stage reimplantation, and requested resectional arthroplasty. A review of the documentation pertaining to the allograft tissue confirmed that the processed meniscal graft was sterile prior to distribution and met all regulations set forth by the American Association of Tissue Banks and the United States Food and Drug Administration25,26.
Two patients, who did well initially, had additional surgery at thirty-two and thirty-six months, respectively, after the index procedure because of a gradual increase in pain. At the time of arthroscopic evaluation, both shoulders demonstrated degeneration of the meniscal allograft tissue. One patient had returned to heavy manual labor and requested a revision meniscal allograft resurfacing of the glenoid with the intent of moving into a supervisory position at his construction company. The other patient was managed with nonsteroidal anti-inflammatory medication and did not feel that current symptoms warranted revision surgery.