Evaluation of regeneration of semitendinosus tendon using ultrasound imaging and isokinetic strength testing after graft harvest for arthroscopic anterior cruciate ligament reconstruction

Musculoskeletal ultrasound imaging of proximal and distal hamstrings cross sectional area in individuals with history of anterior cruciate ligament reconstruction

BACKGROUND

Ultrasound (US) imaging is used by physical therapists for diagnosis and assessment of musculoskeletal injury and follow-up.

PURPOSE

The aim was to identify long-term effects of graft harvesting on hamstrings muscle mass among athletes who had undergone anterior cruciate ligament reconstruction (ACLR).

METHODS

Twenty-eight participants (ages 18-55) were recruited: 18 with history of ACLR using semitendinosus (ST) autograft and 10 healthy controls. Images of the cross-sectional area (CSA) of ST and biceps femoris (BF) were captured at 30% and 70% of the distance from the ischial tuberosity to the popliteal crease. A mixed model ANOVA was used to identify inter-limb differences in the CSA of ST and BF at each location, for each group.

RESULTS

Inter-limb differences were found for the CSA of ST but not BF across both locations for the ACLR group, not controls (p < .001). Within the ACLR group, ST atrophy of the injured limb was relatively greater at the distal vs. proximal location (p < .001).

CONCLUSION

US imaging identified selective atrophy of ST on the injured side with no compensatory hypertrophy of BF. Specific rehabilitation may influence muscle mass of medial vs. lateral hamstrings muscle groups after ACLR using a ST graft, and monitored with US imaging.

Characterizing focal muscle signal on MRI in flexor-pronator muscles' status post ulnar collateral ligament reconstruction

OBJECTIVE

Focal high signal is commonly seen about the flexor pronator mass on MRI in some patients after ulnar collateral ligament (UCL) reconstruction of the elbow. The etiology of this high signal is unclear and not described in literature. The hypothesis is that the edema we see on post-operative MRI is related to palmaris longus graft harvest rather than secondary to other causes of muscle edema such as denervation or muscle strain.

METHODS AND MATERIALS

An IRB waiver-approved, retrospective search of our radiology database was conducted using the keywords "ucl," "elbow," and "reconstruction" between 1/01/2012 and 1/01/2022, with search parameters set as MRI for exam type. The images were reviewed to evaluate for high signal at the flexor pronator mass by a junior and a senior musculoskeletal radiologist. The surgical notes were then reviewed in electronic medical record system to see which graft was used for the UCL reconstruction.

RESULTS

The cohort comprised of 33 patients (1 female/32males, 14-51 years old) who had undergone UCL reconstructions. Four patients were excluded from the study secondary to the surgical note not specifying which graft was used. The surgical and imaging dates were also recorded with the largest time gap of 7 years between the surgery and imaging. Seventeen of the 29 patients had palmaris longus harvested from the ipsilateral arm, 1 patient had palmaris longus harvested from the contralateral arm, 2 patients had an internal brace, and 9 patients had a hamstring graft. Seventeen out of 17 (100%) patients with ipsilateral palmaris longus graft demonstrated focal edema at the flexor pronator mass while 0/12 of the patients without the palmaris longus graft showed the focal edema seen by its counterparts.

CONCLUSION

High signal which is commonly seen at the flexor pronator mass in patient status most UCL reconstruction of the elbow is secondary to the palmaris longus harvest rather than other etiologies such as muscle strain, retear, or trauma.

Relevant Strength Parameters to Allow Return to Running after Primary Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autograft

After anterior cruciate ligament reconstruction (ACLR), a progressive process is followed from rehabilitation to the return to sport including a crucial step known as the return to running. Return to running (RTR) can be predicted by an isokinetic knee strength assessment at 4 months post-surgery. All patients who had primarily undergone ACLR with a hamstring autograft procedure between 2010 and 2020 were included in this study. Four months after surgery, patients were evaluated using an isokinetic knee strength test. Patients were monitored until the 6th month post-surgery to see if they had returned to running. Comparisons were carried out between the two groups—the RTR and the no-RTR. A multivariate logistic regression analysis was used to predict the RTR status from explicative parameters. Receiver Operating Characteristic (ROC) curves were established to identify cutoffs with their characteristics. A total of 413 patients were included and 63.2% returned to running at 4 months post-surgery. The mean Lysholm score, knee complication rate, and isokinetic parameters were statistically different between both groups. Using a multivariate logistic regression model and ROC curves, the best isokinetic parameter to assist with the decision to allow an RTR was the quadriceps limb symmetry index at 60°/s with a cutoff of 65%. The hamstring LSI at 180°/s could be added (cutoff of 80%) to slightly increase the prediction of an RTR. Quadriceps strength normalized to body weight at 60°/s is a useful parameter (cutoff: 1.60 Nm/kg) but measurements on both sides are necessary. Isokinetic parameters are objective parameters to allow a return to running at 4 months after ACLR with a hamstring procedure.

Anatomical retraction of the semitendinosus muscle following harvest of the distal semitendinosus tendon for ACL reconstruction

PURPOSE

Retraction of semitendinosus muscle has been reported after reconstruction of the anterior cruciate ligament with semitendinosus/gracilis-graft. However, very little data exist on the natural variation in side-to-side length symmetry. The purpose of this study was to investigate the side-to-side asymmetry of semitendinosus muscle length in individuals with ACL reconstruction (ACLR) using the semitendinosus/gracilis-graft compared to a group of healthy control subjects to establish the level of retraction that can confidently be ascribed the surgery.

METHODS

Eleven subjects aged 30 (19-39) years, with previous unilateral ACLR with the combined semitendinosus/gracilis tendon graft were recruited. Average follow-up was 6.8 years (0.3-13.0) after reconstruction. Ten healthy subjects aged 30 years (23-36) with no previous knee surgery served as controls. Bilateral magnetic resonance imaging (MRI) scans were obtained of the thigh from 60 mm below the knee joint and 700 mm proximal to this point with a slice thickness of 5 mm with 5 mm inter-slice distance. Semitendinosus length was measured on both legs between the distal and proximal musculotendinous junction of the semitendinosus. Length difference between legs was calculated for all participants. Percentage of shortening was expressed relative to the healthy leg.

RESULTS

Subjects who had undergone ACLR had on average 81 mm (25%) shortening of the semitendinosus on the reconstructed leg compared to the non-reconstructed side. The healthy subjects all had less than 10 mm difference between legs (< 3%). The side-to-side difference was significantly different between the reconstructed patients and the healthy subjects (p < 0.001).

CONCLUSION

This study indicates that retraction larger than 10 mm is a consequence of the tendon harvest and not natural variation. It also supports that persistent retraction of the semitendinosus muscle occurs following harvest of the semitendinosus tendon for ACL graft.

LEVEL OF EVIDENCE

Level IV.