Microinstability characterised by small and easily overlooked anterior labral or Hill–Sachs lesions can be managed with arthroscopic anterior labral repair

Abstract

Purpose Some young individuals present with shoulder pain without a deinite history or complaint of instability. However, careful history taking, physical examination, and high-quality magnetic resonance imaging may reveal evidence of instability of which the patient is unaware. Therefore, a clearer deinition of these ambiguous patients is needed. This study aimed to report the characteristics and surgical outcomes of patients with microinstability compared to those of patients with classic recurrent anterior shoulder instability. Methods From 2005 to 2018, 35 patients with microinstability (group M) underwent arthroscopic anterior labral repair (AALR) and were compared to 35 sex-and age-matched patients with classic recurrent anterior shoulder instability (group C) who also underwent AALR. Baseline characteristics, preoperative apprehension test indings, preoperative imaging for the presence of anterior labral and Hill-Sachs lesions, preoperative and postoperative (over 2 years) range of motion (ROM) and functional scores, inal complications, and patient satisfaction were analysed. ResultsThe most common chief complaints in groups M and C were pain (29/35) and both pain and instability (27/35), respectively. Only pain during the apprehension test was predominant in group M (M vs. C, 27 vs. 1, p < 0.001). High incidence of chronic repetitive injuries (26/35) and acute trauma (28/35) were observed in groups M and C, respectively. Over half of the patients in group M showed anterior labral lesions on magnetic resonance arthrography (MRA, 18/35), and 21 patients had Hill-Sachs lesions on MRA/three-dimensional computed tomography. Finally, 29 patients showed either anterior labral or Hill-Sachs lesions on preoperative imaging. The lesion severity was higher in group C than that in group M. All patients underwent AALR with/without the remplissage procedure, with no signiicant diferences in inal clinical outcomes, complications, and patient satisfaction between the groups. Conclusions Microinstability is diagnostically challenging and can be diagnosed in young patients with ambiguous shoulder pain during motion, without instability. Pain on anterior apprehension test and subtle labral and/or Hill-Sachs lesion on imaging study could be diagnostic clues. This condition can be managed with arthroscopic anterior labral repair with or without the remplissage procedure. The possibility of microinstability in young patients with shoulder pain should always be considered, and small anterior labral or Hill-Sachs lesions should be closely monitored. Level of evidence III.

Reconsidering “Critical” Bone Loss in Shoulder Instability: 17-Year Follow-Up Study following Arthroscopic Bankart Repair

“…The impairment in WOSI (physical symptoms and total) scores at a minimal critical bone loss level of 7% or more as shown in this study most likely reflects microinstability symptoms. This microinstability symptom has also been described in shoulders with Bankart lesions having clinically recurrent and painful micromotion without a history of dislocation [ 26 ]. This group of patients is similar to our cohort with minimal critical bone loss in presentation as both of them have mild symptoms without frank dislocation [ 26 ].…”

“…This microinstability symptom has also been described in shoulders with Bankart lesions having clinically recurrent and painful micromotion without a history of dislocation [ 26 ]. This group of patients is similar to our cohort with minimal critical bone loss in presentation as both of them have mild symptoms without frank dislocation [ 26 ]. The differences in WOSI scores (physical symptoms and total domains) reported in our study are approximately close to the reported minimal clinically important difference (MCID).…”