Problem Focused Arthroscopic Treatment of Shoulder Instability
Abstract & Commentary
Synopsis: Arthroscopic techniques were specifically directed toward each of the pathological entities encountered, including reattachment of Bankart lesions as well as SLAP lesions, tensioning and shrinking the capsular stretch, and plicating the rotator interval. With intermediate follow-up, Gartsman and colleagues were able to achieve success rates in excess of 90% that approached open methods.
Source: Gartsman G, et al. Arthroscopic treatment of anterior/inferior glenohumeral instability. J Bone Joint Surg Am 2000;82:991-1003.
Many prior reports of arthroscopic techniques to address shoulder instability have focused on repairing the Bankart lesion alone, often with trans-glenoid suture techniques. A major shortcoming of this technique was failure to shift the capsule superiorly and laterally to restore its attachment on the corner of the glenoid as a bumper. Newer techniques with suture anchors may offer an advantage in that regard, and even newer techniques involving capsular shrinkage with heat applications offer the ability to shrink the capsule and the redundancy that accompanies a Bankart lesion. This paper by Gartsman and colleagues is one of the first to present the results of arthroscopic techniques to correct instability using suture anchors combined with other methods to correct the pathology that accompanies a Bankart lesion with shoulder instability. They site failure rates with other arthroscopic techniques of 15-50% and stress that success rates can be increased by treating all of the lesions at the same time. They feel that arthroscopic intervention with its increased visibility and diagnostic capability offers an advantage to open procedures in this regard.
This was a prospective study of 53 patients with a mean age of 32 years. These were largely recreational athletes with low demands on the shoulder who were symptomatic with daily activities. Patients were rated pre- and post operatively with four different shoulder rating systems: the American Shoulder and Elbow Surgeons (ASES) shoulder index, the rating system of Constant and Murley, the rating system of ROWE, and the UCLA rating system. The arthroscopic intervention involved a systematic evaluation of the pathology in the joint with repair directed accordingly. Small flap tears of the labrum were debrided. Bankart lesions and labral detachments were repaired, mainly with suture anchors. If the capsule was shifted medially on the scapular neck, it was detached and brought back to the appropriate position. They stressed their effort to bring the capsule and labral complex up on the corner of the glenoid articular surface to act as a bumper and avoid fixing this medially on the scapular neck, which would increase capsular redundancy. They also mobilized the capsule superiorly before attaching it on the glenoid surface. Virtually, all the patients had a Bankart lesion that was repaired. In addition, 31 of 53 had concomitant SLAP lesions that were also repaired. Next, they addressed any additional capsular redundancy by thermal plication using the Holmium-Yag laser. This was done in 48 of 53 patients. Finally, if there was still some inferior laxity, plication sutures were placed in the rotator interval to tighten this from above.
Clinically, the patients enjoyed a 92% success rate in terms of correction of the instability without further dislocations. Subjectively, they also did very well with substantial improvements with all of the rating systems demonstrated. In fact, 92% of the patients achieved a good or excellent score according to both the ROWE and UCLA scoring systems. This met their preoperative hypothesis that arthroscopic surgery effectively treats instability with a mean ROWE score of greater than 85 points for a satisfactory result. Thus, they conclude that their technique to address each element of pathology arthroscopically was an improvement on previous arthroscopic techniques and equivalent to open repair. Factors that reached statistical significance associated with less favorable outcome included an increased number of preoperative dislocations, younger age, longer duration of instability, and generalized ligamentous laxity.
Comment by David R. Diduch, MS, MD
Although the shoulder literature is extensive regarding arthroscopic interventions for instability, this paper represents a shift in terms of the techniques used. This is one of the first papers that involves multiple interventions specifically addressing each element of pathology. The Bankart lesion was not the only thing corrected. Rather, they were aggressive in repairing SLAP lesions, advancing the capsule, reducing capsular redundancy with thermal shrinkage and even plicating the rotator interval. The results are good, in excess of 90% both clinically and subjectively. Admittedly, the follow-up is short with a mean of 33 months, but the results did not deteriorate with duration of follow-up. This is an important distinction from previous arthroscopic interventions where early success between one and two years seemed to deteriorate at 3-4 years.
This is also one of the first few papers to specifically use the combination of suture anchors and capsular shrinkage. This combination allows the surgeon not only to repair the Bankart, but also to advance it up on the glenoid rim toward the articular surface to recreate the bumper effect and the appropriate concavity of the glenoid articular surface. This is a major difference from the trans glenoid techniques that tend to fix the labrum and capsule onto the scapular neck more medially. Furthermore, the capsular shrinkage allows correction of any additional stretch that cannot be corrected with the shift superiorly of the capsule alone. Although Gartsman et al used the laser, we would not expect a significant difference with use of the other thermal shrinkage modalities currently used. Although these techniques have rapidly gained clinical acceptance, little has been published thus far on their effectiveness. This paper is helpful in this regard. It is important to note that in no case did they feel the thermal technique was sufficient alone to correct the instability. It was always used in combination with repair and shift of the capsule onto the glenoid.
The number of SLAP lesions that Gartsman et al repaired, 31 out of 53 patients, is a bit surprising. These were also fixed with suture anchor techniques. Although Gartsman et al point out that they are aggressive in repairing labral pathology, it has not been my experience that SLAP lesions are this prevalent. Admittedly, the diagnosis of a SLAP lesion is not always clear cut. There is a range of anatomic variance involving the superior labrum, and in my hands, assessment of the biceps anchor stability is most important. The concept that the entire labrum and capsule complex circumferentially plays a role in stability supports the notion that type II SLAP lesions are an important component of shoulder instability. This concept is emerging in its acceptance and understanding. A paper by Craig Morgan previously reviewed in Sports Medicine Reports (January 1999) helps with our understanding of this issue.1
Lastly, Gartsman et al’s attention to the rotator interval is to be commended. I admit that this is a difficult area for me to assess what is pathological and what is not. Their approach was to place a suture and apply tension as they assessed the shoulder stability and translation arthroscopically. If there was instability remaining after everything else had been repaired, they tightened the rotator interval. More studies are needed to better understand the importance of the rotator interval in shoulder instability, but it would appear that tightening this interval superiorly helps decrease inferior translation.2
In summary, this is a thorough and exhaustive paper with excellent follow-up that was designed prospectively. The statistics are appropriately rigorous and complete. A power analysis was performed to determine sample size. The clinical and subjective results are excellent and basically equal to those obtained with open methods, while preserving excellent rotation with less perioperative pain. Gartsman et al state that they now perform arthroscopic stabilizations exclusively for these reasons. If their results hold up over the long-term follow-up, it is likely that we will continue to see a shift in the orthopaedic community in the arthroscopic direction.
References
1. Morgan CD, et al. Type II SLAP lesions: Three subtypes and their relationships to superior instability and rotator cuff tears. Arthroscopy 1998;14:553-565.
2. Gartsman G, et al. Arthroscopic rotator interval repair in gleno-humeral instability. Arthroscopy 1999;15: 330-333.
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