MRI-confirmed tear and spontaneous healing of the anterior cruciate ligament

Spontaneous healing of a tear of an anterior cruciate ligament graft: A case report

BACKGROUND

Almost 30% of young athletic patients sustain a second anterior cruciate ligament (ACL) injury within 24months of their ACL reconstruction and returning to pivoting sports. Most patients with high athletic demand and significant anteroposterior instability often require ACL revision surgery to restore their pre-injury activity levels.

CASE REPORT

A 24-year old gentleman ruptured his hamstring tendon autograft during a twisting injury seven months after his ACL reconstruction. Eight months post-injury, it was observed that spontaneous healing of his graft had occurred. This was confirmed with clinical examination and radiological imaging.

CONCLUSION

Hamstring tendon autografts may demonstrate some self-reparative potential. This could be due to the higher response of extra-articular ligaments and tendons in response to growth factors observed in some studies. Limitations in diagnostic magnetic resonance imaging could also lead to over-interpretation of a partially torn graft.

Role of tear location on outcomes of open primary repair of the anterior cruciate ligament: A systematic review of historical studies

BACKGROUND

The general opinion is that outcomes of open primary repair of the anterior cruciate ligament (ACL) in the historical literature were disappointing. Since good outcomes of primary repair of proximal tears have recently been reported, we aimed to assess the role of tear location on open primary repair outcomes in the historical literature.

METHODS

All studies reporting outcomes of open primary ACL repair published between the inception of PubMed, Embase and Cochrane and 2000 were identified. Studies were included if tear location was reported. Outcome scores, return to sports, stability examinations, failures and patient satisfaction were collected and reviewed in the total study cohort and in a subgroup of studies treating only proximal tears. Spearman correlation analysis was performed between the percentage of proximal tears in the studies and all outcomes.

RESULTS

Twenty-nine studies were included reporting outcomes of open primary in 1457 patients of which 72% had proximal and 23% midsubstance tears. Mean age was 30years, 65% were males, and mean follow-up was 3.6years. Good outcomes were noted in the total cohort, and excellent outcomes were noted following repair of proximal tears. Positive correlation was found between the percentage proximal tears in the studies and percentage satisfied patients (p=0.010).

CONCLUSION

Tear location seems to have played a role on the outcomes of open primary ACL repair. Outcomes of open primary repair in patients with proximal tears were excellent, which confirms there may be a potential role for primary repair as treatment for proximal ACL tears.

Gap formation following primary repair of the anterior cruciate ligament: A biomechanical evaluation

BACKGROUND

Historically, inconsistent and unpredictable results of open primary anterior cruciate ligament (ACL) repair were reported. Recently, however, good results of arthroscopic primary ACL repair of proximal tears have been reported. Purpose of this study was to assess the direct postoperative gap formation and maximum failure load following simulated knee motion after primary ACL repair.

METHODS

Six matched-paired human cadaveric knees (mean age: 52years, range: 48 to 56years) were used. After primary proximal ACL repair with either suture button fixation or suture anchor fixation, knees were cycled five, 50 and 100 times with a simulated active quadriceps force. Gap formation between the femoral wall and ligament was measured using a digital caliper and maximum failure load was tested.

RESULTS

Gap formation after five, 50 and 100cycles of the knee were 0.30mm (±0.23), 0.75mm (±0.55) and 0.97mm (±0.70), respectively, with no significant differences between both fixation techniques. The overall maximum failure load was 243N (±143) with no difference between both techniques. Most common failure mode was slipping of suture from the fixation.

CONCLUSION

Following proximal ACL repair, gap formation of approximately one millimeter was measured after repetitious knee cycling with mean maximum failure load of 243N. These findings are likely to be sufficient for careful early active range of motion (ROM) when extrapolating from other available studies. Future studies with second-look arthroscopy are necessary to assess the gap formation and healing in patients treated with primary repair.