ASSESSMENT OF THE REGENERATION CAPACITY OF SEMITENDINOSUS AND GRACILIS TENDONS

Higher rates of anatomical insertion of medial hamstring tendon regeneration post-anterior cruciate ligament reconstruction with stump preservation graft harvesting technique: A prospective, randomised, double-blinded clinical trial with magnetic resonance imaging evaluation

OBJECTIVE(S)

The purpose of this study was to compare the regeneration of semitendinosus and gracilis tendons from two different graft harvesting techniques, which are the stump preservation and conventional graft harvesting techniques. We hypothesised that the stump preservation graft harvesting technique, which preserved the distal attachment of tendons at their insertion, would facilitate anatomical regeneration to the pes anserinus.

METHODS

This is a prospective, randomised, double-blinded study whereby thirty consecutive patients who underwent single bundle anterior cruciate ligament reconstruction with ipsilateral semitendinosus and gracilis autografts were recruited. The patients were randomly assigned to the stump preservation group (14 patients) or conventional group (16 patients). Magnetic resonance imaging (MRI) evaluation was performed preoperatively and at six months post-operatively.

RESULTS

At 6-month follow-up, MRI evaluations showed a higher percentage of insertion of regenerated semitendinosus and gracilis at the pes anserinus in the stump preservation group (75.0%) than that in the conventional group (68.8%). There was a significantly higher proximal shift of the musculotendinous junction of semitendinosus (5.70 ​cm versus 3.36 ​cm, p ​= ​0.029) and gracilis (5.28 ​cm versus 3.16 ​cm, p ​= ​0.045) in the conventional group post-operatively.

CONCLUSION

The stump preservation technique yields a higher percentage of anatomical insertion of regenerated tendons and a lesser amount of proximal shift of the musculotendinous junction.

LEVEL OF EVIDENCE

III - Prospective study with up to two negative criteria.

Is there significant regeneration of the hamstring tendons after harvest for ACL reconstruction? A systematic review of literature

BACKGROUND

Regeneration potential of Hamstring tendons after harvest assumes significant clinical relevance as its use has become widespread today. Methods which best assess the regeneration, extent and type of regeneration, plus issues related to functional loss are important for the surgeon to know. This review looks at the literature to find answers to the above questions.

PURPOSE

To summarize the evidence in support of hamstring tendon regeneration, and the most appropriate modality for evaluation of regeneration. Additionally, to evaluate the regeneration in terms of complete or partial, extent and its impact on strength deficit and functional outcomes.

METHODS

We did a systematic review of literature through specified search engines and identified 30 of 285 studies to be relevant (19 prospective and 11 retrospective).

RESULTS

Evaluation of above data suggests tissue regeneration at harvest sites does occur (78.9% of semitendinosus and 42.7% of gracilis tendons), but this regeneration is variable. No established definition of regeneration exists; MRI is an adequate tool to identify regeneration, while biopsy is confirmative. USG is a cost-effective screening method and can document distal progress of regenerate. Semitendinosus and gracilis tendons regenerate at different rates and extents, and often fuse together, but there is no evidence to state that one regenerates better than the other. Proximal retraction of the muscle-tendon junction occurs, along with some atrophy, which affects function to a variable extent. Strength deficits may persist, but they may not convert to significant functional deficits.

CONCLUSION

There is variable hamstring regeneration after harvest, with poorly defined definition of "regeneration". Some changes in the muscle itself, abnormal distal insertion and absence of regeneration in some are documented, along with strength deficits. Although overall functional deficits have been reported to be minimal, a definite change in the anatomy of the medial hamstrings is a factor to be kept in consideration. More information is needed about the long-term consequences.

Isolated gracilis tendon harvesting is not associated with loss of strength and maintains good functional outcome

PURPOSE

The gracilis tendon is a commonly used autologous graft. Most information on knee function and outcomes after its harvest is related to both semitendinosus- and gracilis tendon harvest. Therefore this study analyzed the effect of isolated gracilis tendon harvest from healthy, uninjured knees on thigh muscle strength and patient reported outcome measures (PROMs).

METHODS

Stabilization of the acromioclavicular joint because of chronic instability was performed with autologous gracilis tendon in 12 patients. After a mean of 44 ± 25 months after surgery, isokinetic peak-torque measurements of specific functions of the gracilis muscle were performed: knee flexion in a sitting position (flexion angles 0-90°) and in prone position (flexion angles > 70°), internal tibial rotation and hip adduction. The contralateral limb was control. Knee specific PROMs were collected including IKDC-2000 subjective evaluation form, Lysholm score, the Marx Activity Rating Scale and SF-36 health survey.

RESULTS

No significant side-to-side differences were found regarding torque measurements. Excellent results were shown regarding the PROMs, which even in terms of IKDC-2000 (97 vs. 82 points, p = 0.001) exceeded significantly the age- and gender matched reference-data.

CONCLUSION

Isolated gracilis tendon harvesting was not associated with loss of strength in knee flexion, internal tibial rotation and thigh adduction. Additionally, good functional outcome as well as excellent knee-specific subjective outcome was found.

LEVEL OF EVIDENCE

III.