In-office needle arthroscopic assessment after primary ACL repair: short-term results in 15 patients – Journal of Experimental Orthopaedics

The main finding of the current study is that in-office needle arthroscopy is a reliable and safe diagnostic tool that allows the ability to assess the healing, the tension, and the synovial coverage of a repaired ACL through direct visualization and probing. Moreover, a statistically significant correlation was found between ACL healing, tension and MRI appearance according to Howell scale and side-to-side difference as evaluated with KT-1000. A correlation between the MRI signal and the biomechanical properties of the anterior cruciate ligament has already been shown by Weiler et al. [24] in a study performed at 2-year follow-up to evaluate the fate of an ACL graft in sheep. They found that high signal intensity on MRI revealed a reduction in the mechanical properties of the graft during the first stages of remodelling. Our study also demonstrated that ACL repair in this patient population can be considered a viable alternative to ACLR.

Accurate patient selection is essential to achieve good clinical outcomes as assessed by Sherman et al. [17] in 1991 and confirmed by numerous subsequent studies [1, 19]. The renewed interest in ACL repair encouraged several authors to show their clinical and radiological outcomes. Di Felice et al. [7] showed excellent results at a mean 3.5- year follow-up after ACL repair with a failure rate of 9% while Achtnich et al. [1], who compared primary ACL repair with ACLR, pointed out similar outcomes with a trend toward more revision after primary repair. In a recent study, Ferretti et al. [9] evaluated in a consecutive series of acute proximal ACL tears, morphology (normal or abnormal) and signal intensity graded against posterior cruciate ligament signal intensity in isointense, intermediate and hyperintense. They found good MRI findings with a normal morphology and signal intensity after ACL repair. Over the past few years, several techniques have been proposed for ACL repair. A recent meta-analysis that evaluated 1101 patients treated with different ACL repair techniques showed a failure rate between 7 and 11% with good outcomes at a mean follow-up of 2.1 years [20]. Another recent systematic review in which the differences between primary ACL repair and ACLR regarding Lysholm score, IKDC, side-to-side laxity difference, pivot shift test, and graft rupture were analyzed showed no significant differences between the two techniques. In addition, excellent mid- and long-term results were shown with the suture anchor repair technique [13].

The in-office needle arthroscopy technology has mainly been reported as a diagnostic tool and has also recently been described as a tool in the treatment of knee, shoulder, and ankle pathologies [5, 16]. Diagnostic in-office shoulder needle arthroscopy allows for a diagnosis at the first patient encounter, especially in pathologies where MRI has low sensitivity such as partial rotator cuff tears. Other recent studies showed a greater diagnostic accuracy using in-office needle arthroscopy as compared with MRI for meniscal tears, chondral defect, and other non-ligamentous pathology [25]. Colasanti et al. [4] found several benefits of using in-office needle arthroscopy for anterior ankle impingement such as quicker patient recovery, patient satisfaction, and cost reduction.

Cost reduction is one of the most repeated themes in several papers on needle arthroscopy. In fact, the cost reduction compared with MRI, already highlighted by Voigt et al. [23] for meniscal injuries, has also been subsequently confirmed by McMillan et al. [16]. They retrospectively reviewed 200 patients undergoing in-office needle arthroscopy diagnostic procedure (175 knees and 25 shoulders) and compared the reimbursements for in-office needle arthroscopy with the cost of diagnostic MRI, finding savings for patients in both the knee and shoulder.

In-office needle arthroscopy was also used to assess the status of a surgically repaired meniscus. DiBartola et al. [6] demonstrated through in-office needle arthroscopy the healing of four repaired horizontal cleavage tears of the medial meniscus and four of the lateral meniscus six months after surgery.

To our knowledge, there is no study on the results of second-look needle arthroscopy of repaired anterior cruciate ligament. There are, however, several second-look arthroscopic reports on reconstructed ACL. Ahn et al. [2] in a previous study performed on 208 patients undergoing anterior cruciate ligament reconstruction with patella bone-tendon-bone (PBTB) autograft or hamstring tendon at a mean follow-up of 21 months, evaluated graft continuity, subjective tension with the probe, and subjective synovial coverage. They demonstrated that the hamstring graft had better synovial coverage than the bone-patellar tendon-bone graft. In contrast, a more recent study by Mae et al. [14], which evaluated reconstructed ACL tension, graft damage, synovial coverage on 113 patients at a mean follow-up of 10 months demonstrated that the bone-patellar tendon- bone was better than the hamstring in anatomic ACLR.

In our study, the clinical outcomes of ACL repair at 2 years of follow-up showed excellent scores and a resumption of normal daily activities and sports in all 15 patients examined. The macroscopical appearance of the ligament was excellent to very good in all cases as well as the subjective tension and synovial coverage. In addition, in-office needle arthroscopy was well tolerated, without complication and allowed immediate return to daily activities.

This study has some limitations: the first is the relatively small sample size and the short follow-up period between the primary ACL repair and the second arthroscopic examination. Another limitation of the study is the lack of a control group of ACLR and related MRI.