Hamstring Autograft Too Small: How Much Allograft Do You Need to Supplement to a Desired Hybrid Graft Size?

No Deficits in Functional Outcomes of the Contralateral Limb Are Seen When the Hamstring Is Harvested for Augmentation of Small Diameter Ipsilateral Hamstring Autograft

Purpose

To evaluate clinical outcomes of the contralateral, nonoperative limb in patients undergoing contralateral hamstring (HS) autograft harvest compared with patients undergoing ipsilateral HS autograft harvest alone.

Methods

This study included 96 patients who underwent isolated anterior cruciate ligament reconstruction (ACLR) using 4-stranded HS autograft (n = 85) or 4-stranded HS autograft augmented with contralateral HS (n = 13) due to inclusion of ipsilateral graft diameter <8 mm. Isokinetic flexion and extension strength and dynamic performance of the ipsilateral and contralateral limbs and limb symmetry index (LSI) were evaluated at 6 months' postoperatively. Rates of contralateral native ACL tear at minimum 2 years also were compared. For all comparisons, P < .05 was considered statistically significant.

Results

Normalized isokinetic knee flexion and extension strength of the contralateral limb did not differ between cohorts (P = .34; P = .21, respectively). LSI for knee extension peak torque and knee flexion peak torque did not differ between cohorts (P = .44; P = .67, respectively). No difference in LSI was seen for any dynamic performance testing (single leg hop, P = .97; triple leg hop, P = .14; 6-m timed hop, P = .99). No difference was observed in International Knee Documentation Committee (P = .99) or Knee Injury and Osteoarthritis Outcome Score subscale measures (P = .39-.86). No difference in rates of contralateral knee native ACL tears were seen between cohorts (HS autograft + contralateral HS augmentation, n = 2, 15.4%; HS autograft, n = 7, 8.4%; P = .26).

Conclusions

In this study, at the time of return to sport, we found no differences in contralateral limb functional performance or limb symmetry measurements between patients undergoing contralateral HS autograft harvest for augmentation of smaller (<8 mm) diameter HS autografts harvested from the injured extremity.

Level of Evidence

Level III, retrospective cohort study.

Anterior Cruciate Ligament Reconstruction Graft Technique Reliably Yields Grafts With 8.0-mm Diameter or Larger

The significance of graft diameter in anterior cruciate ligament reconstruction (ACLR) with soft tissue grafts is well established, with a minimum graft diameter of 8.0 mm associated with lower rates of revision surgery. Consistently achieving grafts that meet or exceed the ideal diameter of 8.0 mm is still a concern with traditional tibial screw fixation, even with quadrupled hamstring autografts. The authors hypothesized that following a simple intraoperative algorithm selectively incorporating the gracilis tendon in an 8-stranded construct for all-inside ACLR with suspensory fixation on both ends of the graft would consistently achieve graft diameters of 8.0 mm or larger by allowing more of the graft material to contribute to increased diameter instead of increased length for screw fixation, with no allograft tissue required. A total of 113 eligible cases were identified, including 70 male patients and 43 female patients (mean±SD age, 25.92±6.47 years; range, 14-49 years). All 113 grafts (100%) were at least 8.0 mm in diameter. There were 8 grafts that were 8.0 mm. Overall mean±SD graft diameter was 9.32±0.71 mm (median, 9.5 mm; range, 8.0-11.0 mm). There were no cases in which allograft tissue was needed to increase graft size. An analysis of 113 cases of all-inside hamstring autograft ACLR with dual suspensory fixation showed that a graft diameter of at least 8.0 mm was achieved in every case, without the use of allograft tissue. These results suggest that this technique for ACLR is reliable in producing grafts that meet or exceed the recommended minimum diameter of 8.0 mm. [Orthopedics. 2021;44(4):e539-e545.].

Allograft Augmentation of Hamstring Autograft in Anterior Cruciate Ligament Reconstruction Results in Equivalent Outcomes to Autograft Alone

PURPOSE

To examine allograft augmentation of undersized hamstring (HS) autograft tendons at the time of anterior cruciate ligament (ACL) reconstruction, compared with un-augmented autograft HS ACL reconstruction.

METHODS

Patients who underwent ACL reconstruction at our institution between 2005 and 2015 were reviewed. Inclusion criteria included patients who underwent (1) primary ACL reconstruction, (2) use of a hybrid HS autograft with allograft augmentation, and (3) had a minimum 2-year postoperative follow-up. Patients with revision ACL, multiligamentous injuries, all-epiphyseal fixation techniques, or additional procedures beyond chondroplasty or meniscal repair/debridement were excluded. Data collected included demographics, graft size, concomitant procedures, revision operation, revision ACL reconstruction, and patient-reported outcomes.

RESULTS

In total, 59 patients met criteria for inclusion into the hybrid group, and 80 patients were eligible for inclusion into the control group. The average age of the cohort was 22.9 (interquartile range Q1:17, Q3: 38.3), and 51.8% of the patients were female. Seven patients (11.9%) in the hybrid ACL group underwent revision ACL surgery versus 15 (18.8%) in the control group (P = .27). There was no difference in patient-reported outcomes between groups.

CONCLUSIONS

Augmenting an HS ACL autograft that is 8 mm or less with allograft tissue to increase the overall size of the ACL graft shows no difference in overall reoperation or revision of ACL failure. The hybrid autograft/allograft ACL reconstruction patients showed no clinically important difference between groups in patient-reported outcome measures.

LEVEL OF EVIDENCE

Level III, case-control comparative analysis.

Editorial Commentary: The Benefits of Three-Dimensional Computed Tomography Images to Evaluate the Safety of All-Inside Meniscal Repair

All-inside meniscal repair is a useful alternative to inside-out repair, particularly for the posterior horn of the lateral meniscus, because open approach to the complex posterolateral corner can be avoided. However, risk to the neurovascular structures is a major concern, and surgeons must be aware of portal placement, degree of penetration, patient size, and patient positioning. Imaging studies may be misleading, as they are generally obtained with the knee in extension. In the future, advanced imaging by 3-dimensional computed tomography may better allow us to preoperatively plan for a safe approach to the posterior horn of the lateral meniscus using all-inside repair techniques.

Editorial Commentary: Built to Last or Just a Trend? Hybrid Graft for Anterior Cruciate Ligament Reconstruction

The use of a hybrid autograft-allograft for primary anterior cruciate ligament reconstruction (ACLR) has gained significant attention in the orthopaedic sports medicine community in recent years. A hybrid graft is most often used to supplement a hamstring autograft with a small diameter, based on evidence that a graft size under a certain diameter (most often 8 mm) increases the risk for graft failure in younger patients. Multiple studies have been published comparing clinical outcomes of ACLR using a hybrid graft versus a hamstring autograft, with conflicting results. Although it is important to attempt to harvest a graft of sufficient size for this procedure, the indications for the use of a hybrid graft for primary ACLR are still unknown.