Tendon is a crucial component of the musculoskeletal system. Tendons connect muscle to bone and transmit forces to produce motion. Chronic and acute tendon injuries are very common and result in ...considerable pain and disability. The management of tendon injuries remains a challenge for clinicians. Effective treatments for tendon injuries are lacking because the understanding of tendon biology lags behind that of the other components of the musculoskeletal system. Animal and cellular models have been developed to study tendon-cell differentiation and tendon repair following injury. These studies have highlighted specific growth factors and transcription factors involved in tenogenesis during developmental and repair processes. Mechanical factors also seem to be essential for tendon development, homeostasis and repair. Mechanical signals are transduced via molecular signalling pathways that trigger adaptive responses in the tendon. Understanding the links between the mechanical and biological parameters involved in tendon development, homeostasis and repair is prerequisite for the identification of effective treatments for chronic and acute tendon injuries.
Category:
Lesser Toes
Introduction/Purpose:
Outcomes of the surgical treatment of dislocated lesser toes have improved significantly over the past few years due to the development of techniques to ...repair plantar plate tears through a dorsal incision. However, treatment of stage 4 tears with no reparable plantar plate can be challenging. The current treatment involves flexor to extensor tendon transfer, requiring multiple incisions and surgical time. An alternative approach is presented, using the same modern techniques of plantar plate repair, but reconstructing the plantar plate using a flexor tendon tenodesis to the plantar base of the proximal phalanx.
Methods:
Four fresh frozen cadaver foot and ankle specimens were used to determine the stability of this new technique. A simulated Lachman’s test was performed on the 2nd, 3 rd, and 4th metatarsophalangeal joints utilizing a force measurement instrument with displacement control on specimens with an intact plantar plate, an excised plantar plate, and following a flexor tenodesis reconstruction.
Results:
The intact plantar plate force was 9.0+2.6kN for 2 mm displacement, and following excision of the plantar plate, the force reduced to 1.3+0.4kN. The flexor tenodesis reconstruction improved the force to 6.0+1.9kN.
Conclusion:
Plantar plate reconstruction with a flexor tenodesis to the proximal phalanx resulted in stability equal to 53% of the intact plantar plate, for the shear displacements between 2 to 6 mm. This procedure may be an alternative treatment option in patients with Stage 4 irreparable plantar plate tears.
Category:
Sports
Introduction/Purpose:
Rupture of the Achilles Tendon (AT) is frequent in young recreational athletes. Conservative management, open surgery and percutaneous/minimally invasive ...approaches are all advocated, and conflicting data are available. This study compared functional and anthropometric outcomes of patients who underwent open or percutaneous repair.
Methods:
A retrospective comparative study, in which 38 patients underwent open and percutaneous techniques to manage AT ruptures. For functional assessment, the calf circumference of both injured and uninjured legs was evaluated. Isokinetic testing included total plantar flexion work, peak plantar flexion torque, total dorsiflexion work peak and dorsiflexion torque. The Achilles Tendon Rupture Score (ATRS) and the America Orthopedic Foot and Ankle Score (AOFAS) were evaluated at a final minimum follow-up of 12 months.
Results:
No major complications were observed. The average time to return to sport was 9 months. AOFAS and ATRS values did not differ statistically between groups. Isokinetic variables and circumference were similar in the operated and non-operated limb in both groups, and did not differ either when comparing open and percutaneous repair.
Conclusion:
Open and percutaneous repair of a torn Achilles tendon produced similar functional outcomes.
Category:
Hindfoot
Introduction/Purpose:
Haglund’s syndrome involves a prominent posterior superior prominence of the calcaneus, in conjunction with pain caused by local inflammation. Nonoperative ...management includes orthotic inserts, immobilization, shoe modification and physical therapy. If non-operative management fails, surgical management with calcaneoplasty is often needed. No study has assessed Achilles tendon pull-out strength after a calcaneoplasty for Haglund’s syndrome. The purpose of this study was to investigate those changes in a cadaveric model and provide objective data upon which to base postoperative recovery.
Methods:
8 matched pairs of cadaveric specimens (mid-tibia to toes) were divided into two cohorts. The matched pairs compared Achilles pull-out strength between intact and open calcaneoplasty specimens. Prior to testing, BMD was determined and lateral X-ray images were obtained before and after surgery to quantify bone removal. The distal aspect of each calcaneus was potted and held at a 20 degree angle. The Achilles tendon was secured in a freeze-clamp, which was attached to a mechanical testing system. Specimens were then loaded to failure. Outcome measures include: Height of bony resection, angle of bone resection, load to failure, and mode of failure.
Results:
Specimens with open calcaneoplasty had a 45% reduction in strength (failure load: 742 N) compared to their intact counterpart (1341 N), p<0.05. Load to failure was significantly correlated with BMD (r=0.64, p<0.05).
Conclusion:
Traditional open calcaneus resection demonstrated a potentially catastrophic weakness of the Achilles tendon insertion. Mineral density further affects weakening of the Achilles insertion. . Biomechanical evidence presented above supports the practice of protected weight bearing and cautious return to activity after open calcaneoplasty for Haglund’s syndrome.
Purpose
The quadriceps tendon (QT) has recently gained interest as an anterior cruciate ligament reconstruction (ACLR) autograft. There is a paucity of data from large cohort studies on failures and ...revision rates after ACLR using the QT graft. The purpose of the present study is to use the Danish Knee Ligament Reconstruction Registry (DKRR) to compare revision rates, objective knee stability and subjective clinical outcomes in patients who have undergone ACLR with QT, hamstring tendon (HT), and patellar tendon (PT) as a graft for ACLR. It was hypothesized that QT autografts would result in similar objective knee stability and revision rates as HT and PT autografts.
Methods
Data on primary ACLRs in the DKRR from 2005 through 2017 were analyzed. Knee injury and Osteoarthritis Outcome Scores (KOOS), Tegner activity scale scores, sagittal knee laxity, pivot-shift tests at 1-year follow-up and revision rates at 2-year follow-up were compared for the three autograft cohorts.
Results
A total of 531 QT, 14,213 HT and 1835 PT ACLR were registered in the DKLR between 2005 and 2017. QT autograft was associated with statistically significant increased laxity (1.8 mm) compared to HT autograft (1.5 mm) (
p
< 0.001) and more positive pivot shift. There was a significant higher revision rate for QT (4.7%), compared to PT (1.5%) and HT (2.3%) autografts at 2-year follow-up (
p
< 0.002).
Conclusion
Quadriceps tendon autografts for ACLR was associated with higher revision rates than HT and PT grafts. QT graft was also associated with small increased objective knee laxity and more positive pivot shift than HT and PT grafts.
Level of evidence
III
Abstract A challenging aspect of subject specific musculoskeletal modeling is the estimation of muscle parameters, especially optimal fiber length and tendon slack length. In this study, the method ...for scaling musculotendon parameters published by Winby et al. (2008) , J. Biomech. 41, 1682–1688, has been reformulated, generalized and applied to two cases of practical interest: 1) the adjustment of muscle parameters in the entire lower limb following linear scaling of a generic model and 2) their estimation “from scratch” in a subject specific model of the hip joint created from medical images. In the first case, the procedure maintained the muscles׳ operating range between models with mean errors below 2.3% of the reference model normalized fiber length value. In the second case, a subject specific model of the hip joint was created using segmented bone geometries and muscle volumes publicly available for a cadaveric specimen from the Living Human Digital Library (LHDL). Estimated optimal fiber lengths were found to be consistent with those of a previously published dataset for all 27 considered muscle bundles except gracilis . However, computed tendon slack lengths differed from tendon lengths measured in the LHDL cadaver, suggesting that tendon slack length should be determined via optimization in subject-specific applications. Overall, the presented methodology could adjust the parameters of a scaled model and enabled the estimation of muscle parameters in newly created subject specific models. All data used in the analyses are of public domain and a tool implementing the algorithm is available at https://simtk.org/home/opt_muscle_par.
Purpose
The purpose of this study was to evaluate the differences in the patient-reported functional outcomes, and graft failure in revision ACL reconstruction using quadriceps tendon (QT), Hamstring ...tendon (HT) and bone-patellar tendon-bone (BPTB) autografts.
Methods
Between 2010 and 2020, 97 patients who underwent revision ACL reconstruction (40 patients received a QT, 26 an HT and 31 a BPTB graft) met the inclusion criteria. Pre-injury and at 2-year postoperatively patients were evaluated for patient-reported functional outcomes; Lysholm knee score, Tegner activity level and VAS (visual analogue scale) for pain; and graft failure. Patient-reported outcomes and graft failure were compared between the QT, HT and BPTB groups. The patients with graft failure were not included for outcome analysis at 2-years of follow-up.
Results
All three revision groups with QT, HT and BPTB autograft did not differ significantly in terms of age, sex, time from injury to surgery, concomitant injuries and single-stage or double-stage procedures (n.s.). No significant difference was found in the pre-injury patient-reported outcome; Lysholm knee score, Tegner activity and VAS for pain (n.s.) between the three groups. At the 2-year follow-up functional outcomes improved in all three groups and all the patients returned to pre-injury activity level; however, no significant difference was found in functional outcomes at the 2-year follow-up between the three groups (n.s.). Graft failure occurred in 4 (10%), 5 (19%) and 3 (10%) patients of QT, HT and BPTB groups, respectively. However, the rate of failure did not differ significantly between groups.
Conclusion
All three autografts (QT, HT and BPTB) demonstrated satisfactory patient-reported outcomes in revision ACL reconstruction. Compared with QT and BPTB grafts, HT graft showed a higher tendency for failure rates. With the increasing incidence of revision ACL reconstruction, surgeons should be aware of all the available graft options. The findings of this study will assist the surgeons in the graft selection for revision ACL reconstruction.
Level of evidence
Level III.
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