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Percutaneous Correction (Humeroplasty) of Humeral Head Defects (Hill-Sachs) Associated With Anterior Shoulder Instability: A Cadaveric Study
Percutaneous Correction (Humeroplasty) of Humeral Head Defects (Hill-Sachs) Associated With Anterior Shoulder Instability: A Cadaveric Study LCDR Michael D. Kazel, D.O., MC, USNR, LCDR Jon K. Sekiya, M.D., MC, USNR, LT Jeffrey A. Greene, P.A.-C., MC, USN, and LT Charles T. Bruker, M.D., MC, USNR
Purpose: The goal of our study was to determine whether a bone tamp could be used to correct a Hill-Sachs lesion by a unique technique that we developed termed “humeroplasty.” Type of Study: In vitro cadaveric study. Methods: We created reproducible Hill-Sachs lesions in 14 cadaveric humerii, which we then reduced with a curved bone tamp using our proposed technique. Paired t tests, with the significance set at P ⬍ .05, were then used to compare the prereduction and postreduction depths, widths, lengths, and volumes of the lesions. Results: The average prereduction defect measurements were 8.9 mm deep, 16.3 mm wide, 24.1 mm long, and 1,755 mm3 in volume. The average postreduction defect measurements were 1.6 mm deep, 6.2 mm wide, 10.4 mm long, and 50.3 mm3 in volume. A statistically significant improvement (P ⬍ .001) was seen in all parameters. Conclusions: Our technique was able to consistently and significantly restore all measured parameters of the Hill-Sachs lesions using a curved bone tamp. This reduction to a “small” defect may reduce the higher rate of recurrence normally found with the surgical treatment of shoulder instability when “large” Hill-Sachs lesions are present. Clinical Relevance: Humeroplasty potentially might reduce the higher rate of recurrence observed when the surgical treatment of shoulder instability involves the presence of large Hill-Sachs lesions. Key Words: Hill-Sachs lesion—Shoulder instability—Humeral head defects.
I
n 1940, Hill and Sachs reported a grooved humeral head defect in 74% (11 of 15) of recurrent shoulder dislocations.1 This defect was described as a true compression fracture resulting from impaction of the soft
From the Bone and Joint/Sports Medicine Institute, Department of Orthopaedic Surgery, Uniformed Services University of the Health Sciences, Naval Medical Center Portsmouth, Portsmouth, Virginia, U.S.A. The Chief, Navy Bureau of Medicine and Surgery, Washington, DC, Clinical Investigation Program sponsored this study (CIP #P03022). The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. Address correspondence and reprint requests to Jon K. Sekiya, M.D., Assistant Professor, Center for Sports Medicine, University of Pittsburgh Medical Center, 3200 South Water St, Pittsburgh, PA, U.S.A. E-mail: [email protected] This is a U.S. government work. There are no restrictions on its use. © 2005 by the Arthroscopy Association of North America 0749-8063/05/2112-4604$30.00/0 doi:10.1016/j.arthro.2005.09.004
cancellous bone of the posterolateral humeral head against the dense anterior rim of the glenoid. This defect has since been considered to be a pathognomonic sign of glenohumeral instability. They went on to conclude that many of these defects were sustained with primary dislocations, and that this may be an etiologic factor for recurrence. The contributions of the Hill-Sachs lesion to recurrent glenohumeral instability and failed anterior instability repairs have been well described.1-6 Most solutions are directed in nonanatomic ways to correct the problem, most commonly by overconstraining the glenohumeral joint by limiting external rotation and thereby preventing lesions from engaging. Among the numerous procedures that have been devised for recurrence are bone graft to the anterior part of the glenoid rim, relocation of the infraspinatus tendon into the defect, humeral rotational osteotomy, osteoarticular allografts, and tightening of structures in the anterior compartment to prevent excessive external rotation and engaging5,7-13 (Miniaci et al., 2004, unpublished data). Few of these procedures are
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 21, No 12 (December), 2005: pp 1473-1478
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FIGURE 1. Humeral head defect creation. (A) Intact humeral head. (B) The edge of a construction hammer was used to model the hard edge of the glenoid rim and impacted into the posterolateral humeral head. (C, D) Two different views of the created Hill-Sachs defect.
directly aimed at correcting the lesion itself or restoring normal anatomy, and some of these solutions have well known complications such as increased glenohumeral arthritis.14 In retrospect, back in 1948, Bankart observed the difficulties in treating this problem and stated “nothing can be done about them [Hill-Sachs lesions] if they are found.”15 More recently, Flatow and Warner stated that Hill-Sachs lesions are rarely large enough to require treatment, but when they are, the reconstruction is made considerably more complex and that, although several options are available, there have been neither acceptable results obtained nor long-term studies available to guide decision-making.12 We propose an anatomic solution that utilizes a bone tamp to correct or decrease the size of large Hill-Sachs
lesions with a technique we will term “humeroplasty.” A bone tamp has been successfully used to treat central tibial articular depressions seen in plateau fractures, and the purpose of our study was to develop a similar technique in the shoulder and to determine whether this technique of humeroplasty could be used to achieve correction of a large Hill-Sachs lesion. Our hypothesis was that our technique would be able to reduce large Hill-Sachs lesions to normal. METHODS Fourteen cadaveric humerii were used for our study. The average age of the specimens was 49.9 years (range, 33 to 70 years). The samples were from 13
PERCUTANEOUS CORRECTION OF HUMERAL HEAD DEFECTS
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tion was obtained (Fig 5). An adequate correction was judged both from direct visualization and from fluoroscopic images. Once the Hill-Sachs lesions were satisfactorily reduced using our humeroplasty technique, the residual defects were measured and recorded by the same method above to determine the postreduction volume restoration. Next, paired t tests were used to compare the prereduction and postreduction parameters, including depth, width, length, and volume. We also compared posthumeroplasty measurements to normal (no lesion). The significance for all calculations was set at P ⫽ .05. RESULTS
FIGURE 2. Volume calculation for Hill-Sachs lesion. Half of a parallelogram was used to approximate the area of the face of the lesion. This area was then multiplied by the length to get the volume estimate.
male and 1 female cadavers. A reproducible, large Hill-Sachs lesion that was morphologically similar to in vivo lesions as defined by previous studies was created.6,16 To do so, a construction hammer with a surface size similar to the average glenoid rim, was placed over the posterolateral area of the humeral head and impacted (Fig 1). The defect depth, width, and length were then measured using a ruler and the measurements used to calculate the volumetric loss from the Hill-Sachs lesion. The lesion area was approximated by the area of half a parallelogram (Fig 2). This area was then multiplied by the length to estimate volume as ½ ⫻ Depth ⫻ Width ⫻ Length ⫽ Volume. The humeroplasty technique is begun with the creation of a cortical window in the mid greater tuberosity just lateral to the bicipital groove, and proximal to the location of the axillary nerve (Fig 3). This location was selected because of its accessibility to the lesions and to avoid injury to the blood supply of the humeral head. Next, a curved bone tamp was placed through the cortical window and was directed toward the defect under fluoroscopic guidance (Fig 4). The bone tamp was then advanced with a mallet, and the tamp direction continually adjusted toward the defect, which elevated a column of bone, compressing the cancellous bone and elevating the lesion until correc-
Large Hill-Sachs lesions were successfully and reproducibly created in vitro. The average depth, width, length, and volume of our Hill-Sachs lesions were measured as 8.9 mm (range, 6 to 11 mm), 16.3 mm (range, 11 to 19 mm), 24.1 mm (range, 18 to 29 mm), and 1,755.6 mm3 (range, 693 to 2,470 mm3), respectively. Following humeroplasty, the defects were reduced to an average depth, width, length, and volume of 1.6 mm (range, 1 to 3 mm), 6.2 mm (range, 3 to 9 mm), 10.4 mm (range, 3 to 18 mm), and 50.3 mm3 (range, 8 to 126 mm3), respectively. All reductions were statistically significant (P ⬍ .001). When the reduced defect dimensions were compared with normal (no lesion), there was a statistically significant difference in all parameters (P ⬍ .001). Although we were not able to prove our hypothesis that humeroplasty can reduce large Hill-Sachs lesions to
FIGURE 3. Starting point for bone tamp entrance. The location is just lateral to the bicipital groove, proximal to the location of the axillary nerve, and between the anterior and posterior blood supply of the humeral head.
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FIGURE 4.
Reduction of lesion using a bone tamp under fluoroscopic guidance. (A) Unreduced defect. (B) Reduced defect.
normal, we were able to significantly reduce these to small defects, as described in previous clinical studies. Our results are summarized in Table 1. DISCUSSION The reported incidence rate of Hill-Sachs lesion associated with anterior dislocation is between 25% and 100%.16-18 Its significance as a cause for recurrent dislocation, and cause for failure of stabilization procedures has been well described.1-6,19 The lesion cre-
FIGURE 5.
ates a shortened rotational arc length that can engage the anterior rim of the glenoid if brought into the athletic position (90° abduction / 0° to 135° of external rotation).2,3,7 Numerous procedures have been devised to prevent the engagement of the Hill-Sachs lesion, but few of these addressed the lesion directly or in an anatomic fashion, seeking instead to correct the problem, most commonly, by overconstraining the glenohumeral joint and preventing lesions from engaging.5,7-13 Neer10 stated that returning the shoulder joint to as near the normal anatomic
(A, B) Two different views showing the reduction of the lesion using a bone tamp under direct visualization.
PERCUTANEOUS CORRECTION OF HUMERAL HEAD DEFECTS TABLE 1.
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Specimen
Age
Sex
D Pre
W Pre
L Pre
V Pre
D Post
W Post
L Post
V Post
1 2 3 4 5 6 7 8 9 10 11 12 13 14 Average
44 44 63 63 33 34 70 39 39 61 61 36 60 52 49.9
M M M M M M F M M M M M M M —
6 9 10 9 9 9 7 8 9 10 11 10 10 7 8.9
19 15 19 18 17 17 11 16 17 15 13 16 18 17 16.3
29 27 26 28 23 21 18 26 21 25 21 24 27 22 24.1
1,653 1,823 2,470 2,268 1,760 1,607 693 1,664 1,607 1,875 1,502 1,920 2,430 1,309 1,755.6
1 2 1 3 0.5 2 1 1 0.5 1 1 2 3 3 1.6
7 7 3 7 6 4 5 8 9 7 5 7 7 5 6.2
6 9 9 11 18 12 3 18 13 8 9 7 12 11 10.4
21 63 14 116 27 48 8 72 29 28 23 49 126 83 50.3
Abbreviations: D, depth of defect; W, width of defect; L, length of defect; V, volume of defect; Pre, prehumeroplasty measurements; Post, posthumeroplasty measurements.
condition as possible is the key to restoring normal function and the elimination of redislocation Also, he felt that a large Hill-Sachs lesion might become hung up on the anterior glenoid rim in external rotation; however, he preferred at the time to do an open anterior repair with additional subscapularis shortening to partially restrict external rotation. Our investigation showed that the normal anatomy (on a cadaver) could be restored with statistical significance into a small lesion as defined by prior studies with our technique of humeroplasty. Rowe et al.8 graded the severity of Hill-Sachs lesion as mild (2.0 cm long and 0.3 cm deep), moderate (4.0 cm long and 0.5 cm deep), and severe (4.0 cm long and 1.0 cm deep). Others have more recently defined the Hill-Sachs notch depths associated with subluxation (2.1 ⫾ 1.0 mm) and dislocation (3.9 ⫾ 0.9 mm) groups.4 More recently, another group again measured and graded the Hill-Sachs lesions in 180 shoulders after primary traumatic anterior dislocation, all of which were found to have a lesion on a series of 3 radiographic views.19 They concluded there was an increase in recurrence rate depending on severity, having had 67% recurrence in those patients with a “Hill-Sachs quotient” of greater than 2.5 cm2 (grade 3) versus 29% overall (23% grade 1, 16% grade 2). Our average posthumeroplasty depths, widths, volumes, and Hill-Sachs quotients (calculated as L ⫻ W ⫻ D as in the above study) were found to be 1.6 mm, 6.2 mm, 50.3 mm3, and 1.0 cm2, respectively, all of which would be considered mild residual lesions according to the definitions set by the studies referenced above. This reduction of a Hill-Sachs lesion potentially con-
verts an engaging lesion into a nonengaging lesion by restoring the rotational arc length. In a case report of a patient with recurrent shoulder instability after an arthroscopic Bankart repair, there was described a Hill-Sachs lesion that engaged at 30° of external rotation despite intact glenohumeral ligaments, which they referred to as an articular arc length mismatch.3 That same group of investigators went on to retrospectively analyze 194 more cases in another study.2 They reported that there were 21 of 194 (11%) recurrences after arthroscopic Bankart repair, and that 14 of those 21 (67%) had significant bone defects described as either an engaging Hill-Sachs lesion or an inverted pear-shaped glenoid. There were only 7 (4%) recurrences when no bony defect was noted (6.5% in contact athletes). When regrouped based on the presence of bony defects, their patients had a 67% recurrence rate (89% in contact athletes). They concluded that these lesions were contraindications to arthroscopic Bankart repair. In our study, this arc length is represented in our measurements by width, and it may indeed have the most profound effect on reducing surgical failures. Miniaci and his associates reported on their series of 18 patients with large humeral head defects who underwent reconstruction with an irradiated humeral allograft followed for an average of 50 months (Miniaci et al, unpublished data, 2004, presented at the Open Meeting of the American Shoulder and Elbow Surgeons, San Francisco, CA). All patients had resolution of their instability with no documented recurrences. Fifteen of the 18 patients had resolution of their preoperative apprehension sign. Two patients required screw removal be-
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M. D. KAZEL ET AL. Acknowledgment: The authors thank LifeNet of Virginia Beach, Virginia, for their assistance in providing cadaveric specimens for this study.
REFERENCES
FIGURE 6.
Potential complication following humeroplasty.
cause of a partial collapse of their graft and symptoms in extreme external rotation. All patients reported that they would undergo the procedure again. The surgery was performed through an open anterior deltopectoral approach. Probably the most important aspect of this technique is that it can be done percutaneously both with minimal invasiveness and with a near anatomic result. This allows the surgeon to avoid the greater morbidity and undesirable results of the methods proposed to date. The significance of this study was that humeroplasty potentially might reduce the higher rate of recurrence when the surgical treatment of shoulder instability involves the presence of large Hill-Sachs lesions, and that this can be done in a minimally invasive fashion with a near anatomic result. Potential complications with this technique are the risk of avascular necrosis of the humeral head, injury to the articular cartilage and axillary nerve, and compartment syndrome that may result from extravasation of fluid if done under arthroscopic guidance (Fig 6). An additional concern is whether any reduction could be achieved using this technique on a chronic as opposed to an acute lesion. The senior author (J.K.S.) has since developed an arthroscopic technique for percutaneous humeroplasty using cannulated coring reamers and bone tamp performed in the beach-chair position (Sekiya et al., unpublished data). Further investigation also remains to help quantify minimal reduction requirements for effectiveness. At present, this technique should be considered experimental. Additional cadaveric research followed by clinical study is needed to further investigate the potential of humeroplasty as a viable technique for augmenting the treatment of anterior shoulder instability when large Hill-Sachs lesions are present.
1. Hill HA, Sachs MD. The grooved defect of the humeral head. A frequently unrecognized complication of dislocations of the shoulder joint. Radiology 1940;35:690-700. 2. Burkhart SS, DeBeer JF. Traumatic glenohumeral bone effects and their relationship to failure of arthroscopic Bankart repairs: Significance of the inverted-pear glenoid and the humeral engaging Hill-Sachs lesion. Arthroscopy 2000;16:677-694. 3. Burkhart SS, Danaceau SM. Articular arc length mismatch as a cause of failed Bankart repair. Arthroscopy 2000;16:740-744. 4. Ito H, Takayama A, Shirai Y. Radiographic evaluation of the Hill-Sachs lesion in patients with recurrent anterior shoulder instability. J Shoulder Elbow Surg 2000;9:495-497. 5. Kirkley A, Griffin S, Richards C, Miniaci A, Mohtadi N. Prospective randomized clinical trial comparing the effectiveness of immediate arthroscopic stabilization versus immobilization and rehabilitation in first traumatic anterior dislocations of the shoulder. Arthroscopy 1999;15:507-514. 6. Richards RD, Sartoris DJ, Pathria MN, Resnick D. Hill-Sachs lesion and normal humeral groove: MR imaging features allowing their differentiation. Radiology 1994;190:665-668. 7. Connolly JF. Humeral head defects associated with shoulder dislocations—Their diagnostic and surgical significance. Instr Course Lect 1972;21:42-54. 8. Rowe CR, Patel D, Southmayd WW. The Bankart procedure. A long-term end-result study. J Bone Joint Surg Am 1978;60:1-16. 9. Weber BG, Simpson LA, Hardegger F. Rotational humeral osteotomy for recurrent anterior dislocation of the shoulder associated with a large Hill-Sachs lesion. J Bone Joint Surg Am 1984;66:1443-1450. 10. Neer CSH. Dislocations. Shoulder reconstruction. Philadelphia: WB Saunders, 1990;273-341. 11. DeBerardino TM, Arciero RA, Taylor DC, Uhorchak JM. Prospective evaluation of arthroscopic stabilization of acute, initial anterior shoulder dislocations in young athletes: Two to five year follow-up. Am J Sports Med 2001;29:586-592. 12. Flatow EL, Warner JJP. Instability of the shoulder: Complex problems and failed repairs: Part I. Relevant biomechanics, multidirectional instability, and severe loss of glenoid and humeral bone. J Bone and Joint Surg Am 1998;80:122-140. 13. Hattrup SJ, Cofield RH, Weaver AL. Anterior shoulder reconstruction: Prognostic variables. J Shoulder and Elbow Surg 2001;10:508-513. 14. Hawkins RJ, Angelo RL. Glenohumeral osteoarthritis: A late complication of the Putti-Platt repair. J Bone and Joint Surg Am 1990;72:1193-1197. 15. Bankart ASB. Discussion on recurrent dislocation of the shoulder. J Bone Joint Surg Br 1948;30:47. 16. Danzig LA, Greenway G, Resnick D. The Hill-Sachs lesion: An experimental study. Am J Sports Med 1980;8:328-332. 17. Calandra JJ, Baker CL, Uribe J. The incidence of Hill-Sachs lesions in initial anterior shoulder dislocations. Arthroscopy 1989;5:254-257. 18. Rowe CR, Zarins B, Ciullo JV. Recurrent anterior dislocation of the shoulder after surgical repair. Apparent causes of failure and treatment. J Bone Joint Surg Am 1984;66:159-168. 19. Kralinger FS, Golser K, Wischatta R, Wambacher M, Sperner G. Predicting recurrence after primary anterior shoulder dislocation. Am J Sports Med 2002;30:116-120.
Purpose: The goal of our study was to determine whether a bone tamp could be used to correct a Hill-Sachs lesion by a unique technique that we developed termed “humeroplasty.” Type of Study: In vitro cadaveric study. Methods: We created reproducible Hill-Sachs lesions in 14 cadaveric humerii, which we then reduced with a curved bone tamp using our proposed technique. Paired t tests, with the significance set at P ⬍ .05, were then used to compare the prereduction and postreduction depths, widths, lengths, and volumes of the lesions. Results: The average prereduction defect measurements were 8.9 mm deep, 16.3 mm wide, 24.1 mm long, and 1,755 mm3 in volume. The average postreduction defect measurements were 1.6 mm deep, 6.2 mm wide, 10.4 mm long, and 50.3 mm3 in volume. A statistically significant improvement (P ⬍ .001) was seen in all parameters. Conclusions: Our technique was able to consistently and significantly restore all measured parameters of the Hill-Sachs lesions using a curved bone tamp. This reduction to a “small” defect may reduce the higher rate of recurrence normally found with the surgical treatment of shoulder instability when “large” Hill-Sachs lesions are present. Clinical Relevance: Humeroplasty potentially might reduce the higher rate of recurrence observed when the surgical treatment of shoulder instability involves the presence of large Hill-Sachs lesions. Key Words: Hill-Sachs lesion—Shoulder instability—Humeral head defects.
I
n 1940, Hill and Sachs reported a grooved humeral head defect in 74% (11 of 15) of recurrent shoulder dislocations.1 This defect was described as a true compression fracture resulting from impaction of the soft
From the Bone and Joint/Sports Medicine Institute, Department of Orthopaedic Surgery, Uniformed Services University of the Health Sciences, Naval Medical Center Portsmouth, Portsmouth, Virginia, U.S.A. The Chief, Navy Bureau of Medicine and Surgery, Washington, DC, Clinical Investigation Program sponsored this study (CIP #P03022). The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government. Address correspondence and reprint requests to Jon K. Sekiya, M.D., Assistant Professor, Center for Sports Medicine, University of Pittsburgh Medical Center, 3200 South Water St, Pittsburgh, PA, U.S.A. E-mail: [email protected] This is a U.S. government work. There are no restrictions on its use. © 2005 by the Arthroscopy Association of North America 0749-8063/05/2112-4604$30.00/0 doi:10.1016/j.arthro.2005.09.004
cancellous bone of the posterolateral humeral head against the dense anterior rim of the glenoid. This defect has since been considered to be a pathognomonic sign of glenohumeral instability. They went on to conclude that many of these defects were sustained with primary dislocations, and that this may be an etiologic factor for recurrence. The contributions of the Hill-Sachs lesion to recurrent glenohumeral instability and failed anterior instability repairs have been well described.1-6 Most solutions are directed in nonanatomic ways to correct the problem, most commonly by overconstraining the glenohumeral joint by limiting external rotation and thereby preventing lesions from engaging. Among the numerous procedures that have been devised for recurrence are bone graft to the anterior part of the glenoid rim, relocation of the infraspinatus tendon into the defect, humeral rotational osteotomy, osteoarticular allografts, and tightening of structures in the anterior compartment to prevent excessive external rotation and engaging5,7-13 (Miniaci et al., 2004, unpublished data). Few of these procedures are
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 21, No 12 (December), 2005: pp 1473-1478
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FIGURE 1. Humeral head defect creation. (A) Intact humeral head. (B) The edge of a construction hammer was used to model the hard edge of the glenoid rim and impacted into the posterolateral humeral head. (C, D) Two different views of the created Hill-Sachs defect.
directly aimed at correcting the lesion itself or restoring normal anatomy, and some of these solutions have well known complications such as increased glenohumeral arthritis.14 In retrospect, back in 1948, Bankart observed the difficulties in treating this problem and stated “nothing can be done about them [Hill-Sachs lesions] if they are found.”15 More recently, Flatow and Warner stated that Hill-Sachs lesions are rarely large enough to require treatment, but when they are, the reconstruction is made considerably more complex and that, although several options are available, there have been neither acceptable results obtained nor long-term studies available to guide decision-making.12 We propose an anatomic solution that utilizes a bone tamp to correct or decrease the size of large Hill-Sachs
lesions with a technique we will term “humeroplasty.” A bone tamp has been successfully used to treat central tibial articular depressions seen in plateau fractures, and the purpose of our study was to develop a similar technique in the shoulder and to determine whether this technique of humeroplasty could be used to achieve correction of a large Hill-Sachs lesion. Our hypothesis was that our technique would be able to reduce large Hill-Sachs lesions to normal. METHODS Fourteen cadaveric humerii were used for our study. The average age of the specimens was 49.9 years (range, 33 to 70 years). The samples were from 13
PERCUTANEOUS CORRECTION OF HUMERAL HEAD DEFECTS
1475
tion was obtained (Fig 5). An adequate correction was judged both from direct visualization and from fluoroscopic images. Once the Hill-Sachs lesions were satisfactorily reduced using our humeroplasty technique, the residual defects were measured and recorded by the same method above to determine the postreduction volume restoration. Next, paired t tests were used to compare the prereduction and postreduction parameters, including depth, width, length, and volume. We also compared posthumeroplasty measurements to normal (no lesion). The significance for all calculations was set at P ⫽ .05. RESULTS
FIGURE 2. Volume calculation for Hill-Sachs lesion. Half of a parallelogram was used to approximate the area of the face of the lesion. This area was then multiplied by the length to get the volume estimate.
male and 1 female cadavers. A reproducible, large Hill-Sachs lesion that was morphologically similar to in vivo lesions as defined by previous studies was created.6,16 To do so, a construction hammer with a surface size similar to the average glenoid rim, was placed over the posterolateral area of the humeral head and impacted (Fig 1). The defect depth, width, and length were then measured using a ruler and the measurements used to calculate the volumetric loss from the Hill-Sachs lesion. The lesion area was approximated by the area of half a parallelogram (Fig 2). This area was then multiplied by the length to estimate volume as ½ ⫻ Depth ⫻ Width ⫻ Length ⫽ Volume. The humeroplasty technique is begun with the creation of a cortical window in the mid greater tuberosity just lateral to the bicipital groove, and proximal to the location of the axillary nerve (Fig 3). This location was selected because of its accessibility to the lesions and to avoid injury to the blood supply of the humeral head. Next, a curved bone tamp was placed through the cortical window and was directed toward the defect under fluoroscopic guidance (Fig 4). The bone tamp was then advanced with a mallet, and the tamp direction continually adjusted toward the defect, which elevated a column of bone, compressing the cancellous bone and elevating the lesion until correc-
Large Hill-Sachs lesions were successfully and reproducibly created in vitro. The average depth, width, length, and volume of our Hill-Sachs lesions were measured as 8.9 mm (range, 6 to 11 mm), 16.3 mm (range, 11 to 19 mm), 24.1 mm (range, 18 to 29 mm), and 1,755.6 mm3 (range, 693 to 2,470 mm3), respectively. Following humeroplasty, the defects were reduced to an average depth, width, length, and volume of 1.6 mm (range, 1 to 3 mm), 6.2 mm (range, 3 to 9 mm), 10.4 mm (range, 3 to 18 mm), and 50.3 mm3 (range, 8 to 126 mm3), respectively. All reductions were statistically significant (P ⬍ .001). When the reduced defect dimensions were compared with normal (no lesion), there was a statistically significant difference in all parameters (P ⬍ .001). Although we were not able to prove our hypothesis that humeroplasty can reduce large Hill-Sachs lesions to
FIGURE 3. Starting point for bone tamp entrance. The location is just lateral to the bicipital groove, proximal to the location of the axillary nerve, and between the anterior and posterior blood supply of the humeral head.
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FIGURE 4.
Reduction of lesion using a bone tamp under fluoroscopic guidance. (A) Unreduced defect. (B) Reduced defect.
normal, we were able to significantly reduce these to small defects, as described in previous clinical studies. Our results are summarized in Table 1. DISCUSSION The reported incidence rate of Hill-Sachs lesion associated with anterior dislocation is between 25% and 100%.16-18 Its significance as a cause for recurrent dislocation, and cause for failure of stabilization procedures has been well described.1-6,19 The lesion cre-
FIGURE 5.
ates a shortened rotational arc length that can engage the anterior rim of the glenoid if brought into the athletic position (90° abduction / 0° to 135° of external rotation).2,3,7 Numerous procedures have been devised to prevent the engagement of the Hill-Sachs lesion, but few of these addressed the lesion directly or in an anatomic fashion, seeking instead to correct the problem, most commonly, by overconstraining the glenohumeral joint and preventing lesions from engaging.5,7-13 Neer10 stated that returning the shoulder joint to as near the normal anatomic
(A, B) Two different views showing the reduction of the lesion using a bone tamp under direct visualization.
PERCUTANEOUS CORRECTION OF HUMERAL HEAD DEFECTS TABLE 1.
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Percutaneous Correction of Humeral Head Defects
Specimen
Age
Sex
D Pre
W Pre
L Pre
V Pre
D Post
W Post
L Post
V Post
1 2 3 4 5 6 7 8 9 10 11 12 13 14 Average
44 44 63 63 33 34 70 39 39 61 61 36 60 52 49.9
M M M M M M F M M M M M M M —
6 9 10 9 9 9 7 8 9 10 11 10 10 7 8.9
19 15 19 18 17 17 11 16 17 15 13 16 18 17 16.3
29 27 26 28 23 21 18 26 21 25 21 24 27 22 24.1
1,653 1,823 2,470 2,268 1,760 1,607 693 1,664 1,607 1,875 1,502 1,920 2,430 1,309 1,755.6
1 2 1 3 0.5 2 1 1 0.5 1 1 2 3 3 1.6
7 7 3 7 6 4 5 8 9 7 5 7 7 5 6.2
6 9 9 11 18 12 3 18 13 8 9 7 12 11 10.4
21 63 14 116 27 48 8 72 29 28 23 49 126 83 50.3
Abbreviations: D, depth of defect; W, width of defect; L, length of defect; V, volume of defect; Pre, prehumeroplasty measurements; Post, posthumeroplasty measurements.
condition as possible is the key to restoring normal function and the elimination of redislocation Also, he felt that a large Hill-Sachs lesion might become hung up on the anterior glenoid rim in external rotation; however, he preferred at the time to do an open anterior repair with additional subscapularis shortening to partially restrict external rotation. Our investigation showed that the normal anatomy (on a cadaver) could be restored with statistical significance into a small lesion as defined by prior studies with our technique of humeroplasty. Rowe et al.8 graded the severity of Hill-Sachs lesion as mild (2.0 cm long and 0.3 cm deep), moderate (4.0 cm long and 0.5 cm deep), and severe (4.0 cm long and 1.0 cm deep). Others have more recently defined the Hill-Sachs notch depths associated with subluxation (2.1 ⫾ 1.0 mm) and dislocation (3.9 ⫾ 0.9 mm) groups.4 More recently, another group again measured and graded the Hill-Sachs lesions in 180 shoulders after primary traumatic anterior dislocation, all of which were found to have a lesion on a series of 3 radiographic views.19 They concluded there was an increase in recurrence rate depending on severity, having had 67% recurrence in those patients with a “Hill-Sachs quotient” of greater than 2.5 cm2 (grade 3) versus 29% overall (23% grade 1, 16% grade 2). Our average posthumeroplasty depths, widths, volumes, and Hill-Sachs quotients (calculated as L ⫻ W ⫻ D as in the above study) were found to be 1.6 mm, 6.2 mm, 50.3 mm3, and 1.0 cm2, respectively, all of which would be considered mild residual lesions according to the definitions set by the studies referenced above. This reduction of a Hill-Sachs lesion potentially con-
verts an engaging lesion into a nonengaging lesion by restoring the rotational arc length. In a case report of a patient with recurrent shoulder instability after an arthroscopic Bankart repair, there was described a Hill-Sachs lesion that engaged at 30° of external rotation despite intact glenohumeral ligaments, which they referred to as an articular arc length mismatch.3 That same group of investigators went on to retrospectively analyze 194 more cases in another study.2 They reported that there were 21 of 194 (11%) recurrences after arthroscopic Bankart repair, and that 14 of those 21 (67%) had significant bone defects described as either an engaging Hill-Sachs lesion or an inverted pear-shaped glenoid. There were only 7 (4%) recurrences when no bony defect was noted (6.5% in contact athletes). When regrouped based on the presence of bony defects, their patients had a 67% recurrence rate (89% in contact athletes). They concluded that these lesions were contraindications to arthroscopic Bankart repair. In our study, this arc length is represented in our measurements by width, and it may indeed have the most profound effect on reducing surgical failures. Miniaci and his associates reported on their series of 18 patients with large humeral head defects who underwent reconstruction with an irradiated humeral allograft followed for an average of 50 months (Miniaci et al, unpublished data, 2004, presented at the Open Meeting of the American Shoulder and Elbow Surgeons, San Francisco, CA). All patients had resolution of their instability with no documented recurrences. Fifteen of the 18 patients had resolution of their preoperative apprehension sign. Two patients required screw removal be-
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M. D. KAZEL ET AL. Acknowledgment: The authors thank LifeNet of Virginia Beach, Virginia, for their assistance in providing cadaveric specimens for this study.
REFERENCES
FIGURE 6.
Potential complication following humeroplasty.
cause of a partial collapse of their graft and symptoms in extreme external rotation. All patients reported that they would undergo the procedure again. The surgery was performed through an open anterior deltopectoral approach. Probably the most important aspect of this technique is that it can be done percutaneously both with minimal invasiveness and with a near anatomic result. This allows the surgeon to avoid the greater morbidity and undesirable results of the methods proposed to date. The significance of this study was that humeroplasty potentially might reduce the higher rate of recurrence when the surgical treatment of shoulder instability involves the presence of large Hill-Sachs lesions, and that this can be done in a minimally invasive fashion with a near anatomic result. Potential complications with this technique are the risk of avascular necrosis of the humeral head, injury to the articular cartilage and axillary nerve, and compartment syndrome that may result from extravasation of fluid if done under arthroscopic guidance (Fig 6). An additional concern is whether any reduction could be achieved using this technique on a chronic as opposed to an acute lesion. The senior author (J.K.S.) has since developed an arthroscopic technique for percutaneous humeroplasty using cannulated coring reamers and bone tamp performed in the beach-chair position (Sekiya et al., unpublished data). Further investigation also remains to help quantify minimal reduction requirements for effectiveness. At present, this technique should be considered experimental. Additional cadaveric research followed by clinical study is needed to further investigate the potential of humeroplasty as a viable technique for augmenting the treatment of anterior shoulder instability when large Hill-Sachs lesions are present.
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