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Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_II | Pages 148 - 148
1 Apr 2005
Pimpalnerkar AL Mohtadi N Ramisetty NM
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The management of symptomatic single bundle Anterior Cruciate Ligament (ACL) ruptures is still a surgical dilemma. Preservation of the intact fibres of the ACL bundle is considered to be a possible source of reinnervation of the ACL autograft which reflects on better proprioceptive knee control after major ligament reconstruction. Results of a prospective study of 67 patients who had a double stranded but single bundle Anterior Cruciate Ligament (ACL) reconstruction for partial ACL ruptures are presented. There were 43 males and 24 females in this study with a mean age at the time of injury of twenty-five years (14 – 40). Eight played sport professionally and thirty-four played at a competitive level. A valgus twisting force was the most common mechanism of injury. Mean injury to operation time was 7.5 weeks (2–12). All procedures were done arthroscopically without using tourniquet, but using an arthroscopy pump and irrigation fluid containing adrenaline. The semitendinosis hamstring graft was used in all reconstructions. The mean follow-up period was 3.3 years (2–5.4). There was one major complication, who developed a reflex sympathetic dystrophy following a saphenous nerve neuroma. The Quality of Life (QOL) score was assessed using the Mohtadi index. The mean pre-operative QOL score of 30 (13–50) was improved to 93 (70–100) post-operatively. Fifty patients were able to return to their previous sporting level at a mean duration of 9 months (6–12). Preservation of mechanoreceptors by performing a double stranded, single bundle ACL reconstruction in partial ACL ruptures in high demand patients yields good results and enables early return to high demand sports


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 18 - 18
1 Mar 2010
Hiemstra LA Heard M Buchko G Sasyniuk TM Reed J Monteleone B
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Purpose: To determine if patients randomized to a knee immobilizer following a primary hamstring tendon anterior cruciate ligament (ACL) reconstruction have lower visual analog scale (VAS) pain scores at day two postoperative than patients who do not wear a knee immobilizer. Method: Patients aged 18–40 with symptomatic ACL deficiency as determined by MRI or physical exam who met the study inclusion criteria were eligible. Patients meeting intra-operative inclusion critiera were randomized (immobilizer or no immobilizer) during wound closure. The immobilizer used was a soft unhinged brace with velcro straps and three metal bars (Breg). Pre, intra and post operative protocols were standardized. Analgesic use and VAS scores were recorded at: one hour after surgery, 8am and 8pm for the first two days postoperative, and 5pm for days 3–14 postoperative. Patients were examined by the surgeon within 14–28 days postoperative. Based on a published survey and the literature, the primary outcome was patient self-assessed pain using a 0–100mm VAS (no pain-worst pain) at day 2 postoperative. Secondary outcomes included: analgesic use, complications, and range of motion. A sample size estimate was calculated resulting in 44 patients per group. A total of 102 patients were enrolled; 88 randomized and 14 excluded intra-operatively. Recruitment was achieved within 11 months. Results: There was no difference in mean VAS pain scores at 2 days post-operative between immobilized and non-immobilized patients (32.6 and 35.2, respectively; p=0.59, 95% CI −6.99, 12.3). Regardless of group allocation, the greatest pain reported was on the evening of day 1 post-operative. Throughout the first week, patients medicated to a pain level of approximately 30/100. There were no differences between groups in medication consumed, range of motion or complications. At 2 days post-operative all patients randomized to the immobilizer group reported that they worn their brace 76–100% of the time. Conclusion: No differences in pain were detected between immobilized and non-immobilized patients at any point during 14 days post ACL reconstruction. Based on these findings, a knee immobilizer is not recommended post-operatively for pain control. This study does not address other reasons for immobilizer use such as graft protection or range of motion


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_III | Pages 230 - 230
1 Mar 2003
Mastrokalos D Rossis J Jiakuo Y Paesssler H
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Introduction: The aim of this study was to evaluate whether a guiding pin for a femoral tunnel could be positioned through the tibial tunnel into the center of the anatomical ACL attachment.

Material and Methods: We studied 77 knees who underwented arthroscopic ACL reconstruction with hamstrings. The femoral tunnel was drilled through an antero-medial portal at the center of the anatomic insertion at about 10 resp. 2 o’clock position. Tibial tunnel (mean diameter 7.55 ± 0.54 mm ) was drilled at 90° of knee flexion. The aiming point was on a line, being a “prolongation” of the posterior border of the anterior horn of the lateral meniscus and at exactly 60% of the distance from the end of the anterior horn of the lateral meniscus and the medial tibial spine. Then, through the tibial tunnel, a 4mm offset femoral drill guide was positioned as close as possible to the femoral tunnel and a 2.5 mm guide wire was drilled. The position of the guide wire was photographed arthroscopically and the deviation was measured as distance between the center of the femoral tunnel and guide wire.

Results: The mean angle of the tibial tunnel in the coronar plain was 27,53° and in the sagittal plain 25,84°, both according to the longitudinal axis of the tibia. In 74 knees ( 96. 1 % ) the guidewire did not reach the femoral tunnel. Only in 3 knees it reached the superomedial edge of the femoral tunnel. The mean deviation was 4.50 ± 1.54 mm (p = 0.00000004 ). No statistical relationship was found between deviation and tibial tunnel inclination angles or tibial tunnel diameter.

Conclusion: Transtibial femoral tunnel drilling did not reach the anatomic side of the ACL insertion in most of the cases, even with larger tibial tunnels (for hamstring grafts up to 8.5 mm). Therefore we recommend tibial tunnel drilling through the anteromedial portal.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 174 - 174
1 May 2011
Parratte S Sorenson M Dahm D Larson D O’Byrne M Pagnano M Stuart M Smith A Berry D
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Introduction: The International Knee Documentation Committee (IKDC) recommends use of the IKDC score to document subjective, objective and functional ACL outcome. To further improve knowledge concerning patient QOL after ACL reconstruction, an additional specific QOL questionnaire was developed. Using a combination of univariate and multivariate analysis the patient factors and surgical factors that influenced QOL 5- years after ACL reconstruction were determined.

Materials: 500 patients operated on for arthroscopic ACL reconstruction at our institution between 1997 and 2001 were prospectively enrolled. Patient psychosocial profile, sport expectations, knee exam, type of graft, associated lesion, type of anesthesia, complications, IKDC, KT 2000 at 6 moths, 1 year and 2 years were recorded. At five years, patients were asked to complete a 5-subscale validated QOL questionnaire for ACL deficiency. A multivariate analysis was performed to identify the factors influencing 5-year QOL.

Results: 203 patients completed the 5-years QOL questionnaire. Responders did not statistically differ from non responders. Patient subjective factors such as: patient expectations, pre-operative symptoms, work-school concerns, recreations concerns, social and psycho-social concerns were significantly (p< 0.05) and independently associated with the five-year QOL results. Objective factors such as meniscus tears and results of the KT 2000 (p< 0.05) were the two surgical factors correlated with 5-year QOL.

Discussion: In this large prospective study, most of the factors influencing the 5-year QOL results after ACL reconstruction were related to patient expectations, psycho-social, symptoms and work-sport concerns. The presence of a meniscus tear and greater KT 2000 laxity also contributed to poorer 5-year QOL results.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_II | Pages 241 - 241
1 May 2009
Chan D Assiri I Gooch K Mohtadi N Sun J Guy P
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ACL deficiency can have detrimental pathological effects on the menisci in the knee. A database review in Quebec over a three-year period was previously reported (Canadian Academy of Sport Medicine, Winnipeg, 2003), which examined the relationship between waiting times for ACL surgery and the requirement of a meniscal procedure. The purpose of this study is to determine if the length of time between an index injury and ACL reconstruction (ACLR) surgery correlates with the incidence of meniscal repair and meniscectomy in Alberta, and to compare the results to those of the Quebec study.

Retrospective study, using procedure and billing codes to search the Alberta Health and Wellness databases for knees undergoing primary ACLR surgery between 2002–2005. Inclusion: Patients sixteen years or older at time of reconstruction. Exclusion: Revision ACLR, duplicate billing and coding, and insufficient database information. For each reconstructed knee, databases were searched for initial injury evaluation date with primary care physician, dates of meniscectomy or meniscal repair procedures, and date of ACLR.

Over a three-year period, there were 3382 primary ACL reconstructions performed in Alberta, 3812 ACLR in Quebec. Of these patients, 2583 in Alberta (76%) and 1722 in Quebec (45%) required a meniscal procedure. On average, Albertans waited 1389 days from injury to ACLR compared to 422 days in Quebec. In Alberta, patients not requiring a meniscal procedure waited 1212 days, patients requiring meniscal repair waited 1143 days, and patients requiring meniscectomy waited 1519 days, compared to 251, 413 and 676 days in Quebec, respectively. Three percent of patients in Alberta had ACLR < three months after injury (114 patients), with 45% requiring meniscectomy. Overall, 61% of patients in Alberta required a meniscectomy for significant meniscal injury, compared to 48% of patients in Quebec. The proportions for each province were statistically significant.

Compared to Quebec, patients in Alberta are waiting longer for ACLR, with only a small proportion of cases being treated acutely. The proportion of patients requiring surgery for significant meniscal injury is also greater in Alberta. The higher proportion of patients in Alberta requiring meniscectomy may be due to the delay in ACLR.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 468 - 468
1 Sep 2009
Valera F Minaya F Melián A Veiga X Leyes M Gutiérrez J
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Anterior knee instability associated with rupture of ACL is a disabling clinical problem, especially in the athletic individual. The gracilis and semitendinosus tendon (T4) represent an alternative autograft donor material for reconstruction of the ACL.

The aim of our study was to elaborate a CPG to assist physiotherapists in decision making and to improve the efficacy and uniformity of care for patients with ACL reconstruction with T4.

The CPG was developed according to international methods of guideline development. To identify “best evidence” a structured search was performed. When no evidence was available, consensus between experts (physiotherapist and orthopaedic surgeons) was achieved to develop the guideline. To identify “best clinical experience” and “physiopathology reasoning” focus group of practicing physiotherapists was used. They reviewed the clinical applicability and feasibility of the guideline, and their comments were used to improve it.

CPG include three phases determined from the evidence, physiopathology reasoning and the biological process of autograft (weeks after the surgery: 2a–6a, 6a–10a and 10a–16a). The recommendations included: In postoperative weeks (2a–6a) physiotherapy focused on early range of motion of the knee; manual therapy (passive range of motion (PROM) 0–120° and miofascial techniques), pulsed ultrasound of low intensity with a power of 0.3w/cm2 (1MHz) during 10min/day in tibial tunnel, early active hamstring beginning with static weight bearing co-contractions (closed-kinetic-chain) and adductors, partial weight bearing with crutches, exercises in the swimming pool and cryotherapy to pain control (30 mi/4 hours). In weeks 6 to 10, full weight bearing, manual therapy (PROM 0–140° and miofascial techniques), hamstring strengthening progress complexity and repetitions of co-contractions, electrotherapy hamstring and quadriceps co-contractions. Starting at week 10, progress to more dynamic activities/movements, proprioceptive work, open-kinetic-chain, stationary bike and Theraband squats. In week 12, progress jogging program and plyometric type activities. The patients performed sports-specific exercises by about 3½ months postoperative.


Bone & Joint Research
Vol. 11, Issue 7 | Pages 503 - 512
25 Jul 2022
Wu Y Shao Y Xie D Pan J Chen H Yao J Liang J Ke H Cai D Zeng C

Aims. To verify whether secretory leucocyte protease inhibitor (SLPI) can promote early tendon-to-bone healing after anterior cruciate ligament (ACL) reconstruction. Methods. In vitro: the mobility of the rat bone mesenchymal stem cells (BMSCs) treated with SLPI was evaluated by scratch assay. Then the expression levels of osteogenic differentiation-related genes were analyzed by real-time quantitative PCR (qPCR) to determine the osteogenic effect of SLPI on BMSCs. In vivo: a rat model of ACL reconstruction was used to verify the effect of SLPI on tendon-to-bone healing. All the animals of the SLPI group and the negative control (NC) group were euthanized for histological evaluation, micro-CT scanning, and biomechanical testing. Results. SLPI improved the migration ability of BMSCs and upregulated the expression of genes related to osteogenic differentiation of BMSCs in vitro. In vivo, the SLPI group had higher histological scores at the tendon-bone interface by histological evaluation. Micro-CT showed more new bone formation and bone ingrowth around the grafted tendon in the SLPI group. Evaluation of the healing strength of the tendon-bone connection showed that the SLPI group had a higher maximum failure force and stiffness. Conclusion. SLPI can effectively promote early tendon-to-bone healing after ACL reconstruction via enhancing the migration and osteogenic differentiation of BMSCs. Cite this article: Bone Joint Res 2022;11(7):503–512


Aims. The aim of this study was to compare the preinjury functional scores with the postinjury preoperative score and postoperative outcome scores following anterior cruciate ligament (ACL) reconstruction surgery (ACLR). Methods. We performed a prospective study on patients who underwent primary ACLR by a single surgeon at a single centre between October 2010 and January 2018. Preoperative preinjury scores were collected at time of first assessment after the index injury. Preoperative (pre- and post-injury), one-year, and two-year postoperative functional outcomes were assessed by using the Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm Knee Score, and Tegner Activity Scale. Results. We enrolled 308 males and 263 females of mean age 27 years (19 to 46). The mean preinjury and preoperative post-injury Lysholm Knee Scores were 94 (73 to 100) and 63 (25 to 85), respectively, while the respective mean scores at one and two years postoperatively were 84 (71 to 100) and 89 (71 to 100; p < 0.001). The mean Tegner preinjury and preoperative post-injury scores were 7 (3 to 9) and 3 (0 to 6), respectively, while the respective mean scores at one and two years postoperatively were 6 (1 to 8) and 6 (1 to 9) (p < 0.001). The mean KOOS scores at preinjury versus two years postoperatively were: symptoms (96 vs 84); pain (94 vs 87); activities of daily living (97 vs 91), sports and recreation function (84 vs 71), and quality of life (82 vs 69), respectively (p < 0.001). Conclusion. Functional scores improved following ACLR surgery at two years in comparison to preoperative post-injury scores. However, at two-year follow-up, the majority of patients failed to achieve their preinjury scores. The evaluation of ACLR outcomes needs to consider the preinjury scores rather than the immediate preoperative score that is usually collected. Cite this article: Bone Jt Open 2023;4(1):46–52


Bone & Joint Open
Vol. 5, Issue 9 | Pages 758 - 765
12 Sep 2024
Gardner J Roman ER Bhimani R Mashni SJ Whitaker JE Smith LS Swiergosz A Malkani AL

Aims. Patient dissatisfaction following primary total knee arthroplasty (TKA) with manual jig-based instruments has been reported to be as high as 30%. Robotic-assisted total knee arthroplasty (RA-TKA) has been increasingly used in an effort to improve patient outcomes, however there is a paucity of literature examining patient satisfaction after RA-TKA. This study aims to identify the incidence of patients who were not satisfied following RA-TKA and to determine factors associated with higher levels of dissatisfaction. Methods. This was a retrospective review of 674 patients who underwent primary TKA between October 2016 and September 2020 with a minimum two-year follow-up. A five-point Likert satisfaction score was used to place patients into two groups: Group A were those who were very dissatisfied, dissatisfied, or neutral (Likert score 1 to 3) and Group B were those who were satisfied or very satisfied (Likert score 4 to 5). Patient demographic data, as well as preoperative and postoperative patient-reported outcome measures, were compared between groups. Results. Overall, 45 patients (6.7%) were in Group A and 629 (93.3%) were in Group B. Group A (vs Group B) had a higher proportion of male sex (p = 0.008), preoperative chronic opioid use (p < 0.001), preoperative psychotropic medication use (p = 0.01), prior anterior cruciate ligament (ACL) reconstruction (p < 0.001), and preoperative symptomatic lumbar spine disease (p = 0.004). Group A was also younger (p = 0.023). Multivariate analysis revealed preoperative opioid use (p = 0.012), prior ACL reconstruction (p = 0.038), male sex (p = 0.006), and preoperative psychotropic medication use (p = 0.001) as independent predictive factors of patient dissatisfaction. Conclusion. The use of RA-TKA demonstrated a high rate of patient satisfaction (629 of 674, 93.3%). Demographics for patients not satisfied following RA-TKA included: male sex, chronic opioid use, chronic psychotropic medication use, and prior ACL reconstruction. Patients in these groups should be identified preoperatively and educated on realistic expectations given their comorbid conditions. Cite this article: Bone Jt Open 2024;5(9):758–765


Bone & Joint 360
Vol. 11, Issue 5 | Pages 18 - 19
1 Oct 2022


Bone & Joint 360
Vol. 11, Issue 3 | Pages 17 - 20
1 Jun 2022


The Bone & Joint Journal
Vol. 105-B, Issue 11 | Pages 1133 - 1134
1 Nov 2023
Haddad FS

Cite this article: Bone Joint J 2023;105-B(11):1133–1134.


The Bone & Joint Journal
Vol. 106-B, Issue 6 | Pages 516 - 521
1 Jun 2024
Al-Hourani K Haddad FS


Bone & Joint Research
Vol. 12, Issue 1 | Pages 9 - 21
9 Jan 2023
Lu C Ho C Chen S Liu Z Chou PP Ho M Tien Y

Aims

The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction.

Methods

The ACL remnant, bone marrow, and hamstring tendons were surgically harvested from rabbits. The apoptosis rate, cell proliferation, and expression of types I and III collagen, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and tenogenic genes (scleraxis (SCX), tenascin C (TNC), and tenomodulin (TNMD)) of the hamstring tendons were compared between the co-culture medium (ACL remnant cells (ACLRCs) and BMSCs co-culture) and control medium (BMSCs-only culture). We also evaluated the apoptosis, cell proliferation, migration, and gene expression of hamstring tenocytes with exposure to co-culture and control media.


Bone & Joint 360
Vol. 11, Issue 2 | Pages 21 - 22
1 Apr 2022


The Bone & Joint Journal
Vol. 104-B, Issue 6 | Pages 680 - 686
1 Jun 2022
Robinson JR Bruce D Davies H Porteous AJ Murray JRD Howells NR

Aims

The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR.

Methods

We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks).


Bone & Joint Open
Vol. 2, Issue 12 | Pages 1043 - 1048
1 Dec 2021

Aims

There is limited information on outcomes of revision ACL reconstruction (rACLR) in soccer (association football) athletes, particularly on return to sport and the rate of additional knee surgery. The purpose of this study was to report return to soccer after rACLR, and to test the hypothesis that patient sex and graft choice are associated with return to play and the likelihood of future knee surgery in soccer players undergoing rACLR.

Methods

Soccer athletes enrolled in a prospective multicentre cohort were contacted to collect ancillary data on their participation in soccer and their return to play following rACLR. Information regarding if and when they returned to play and their current playing status was recorded. If they were not currently playing soccer, they were asked the primary reason they stopped playing. Information on any subsequent knee surgery following their index rACLR was also collected. Player demographic data and graft choice were collected from their baseline enrolment data at rACLR.


Bone & Joint Open
Vol. 2, Issue 8 | Pages 569 - 575
1 Aug 2021
Bouguennec N Robinson J Douiri A Graveleau N Colombet PD

Aims

MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation.

Methods

A consecutive cohort of 149 patients who had undergone semitendinosus autograft ACL reconstruction, using femoral and tibial adjustable loop fixations, were evaluated retrospectively postoperatively at two years. All underwent MRI analysis of the ACL graft, performed using signal-to-noise quotient (SNQ) and the Howell score. Functional outcome scores (Lysholm, Tegner, International Knee Documentation Committee (IKDC) subjective, and IKDC objective) were obtained and all patients underwent instrumented side-to-side anterior laxity differential laxity testing.


Bone & Joint Research
Vol. 9, Issue 6 | Pages 293 - 301
1 Jun 2020
Hexter AT Hing KA Haddad FS Blunn G

Aims. To evaluate graft healing of decellularized porcine superflexor tendon (pSFT) xenograft in an ovine anterior cruciate ligament (ACL) reconstruction model using two femoral fixation devices. Also, to determine if pSFT allows functional recovery of gait as compared with the preoperative measurements. Methods. A total of 12 sheep underwent unilateral single-bundle ACL reconstruction using pSFT. Two femoral fixation devices were investigated: Group 1 (n = 6) used cortical suspensory fixation (Endobutton CL) and Group 2 (n = 6) used cross-pin fixation (Stratis ST). A soft screw was used for tibial fixation. Functional recovery was quantified using force plate analysis at weeks 5, 8, and 11. The sheep were euthanized after 12 weeks and comprehensive histological analysis characterized graft healing at the graft-bone interface and the intra-articular graft (ligamentization). Results. The pSFT remodelled into a ligament-like structure and no adverse inflammatory reaction was seen. The ground reaction force in the operated leg of the Endobutton group was higher at 11 weeks (p < 0.05). An indirect insertion was seen at the graft-bone interface characterized by Sharpey-like fibres. Qualitative differences in tendon remodelling were seen between the two groups, with greater crimp-like organization and more aligned collagen fibres seen with Endobutton fixation. One graft rupture occurred in the cross-pin group, which histologically showed low collagen organization. Conclusion. Decellularized pSFT xenograft remodels into a ligament-like structure after 12 weeks and regenerates an indirect-type insertion with Sharpey-like fibres. No adverse inflammatory reaction was observed. Cortical suspensory femoral fixation was associated with more enhanced graft remodelling and earlier functional recovery when compared with the stiffer cross-pin fixation


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 91 - 91
2 Jan 2024
Kamalitdinov T Fujino K Jiang X Madi R Marcelin J Kuntz A Dyment N
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Despite extensive research aimed at improving surgical outcomes of enthesis injuries, re-tears remain a common problem, as the repairs often lead to fibrovascular scar as opposed to a zonal enthesis. Zonal enthesis formation involves anchoring collagen fibers, synthesizing proteoglycan-rich fibrocartilage, and mineralizing this fibrocartilage [1]. During development, the hedgehog signaling pathway promotes the formation and maturation of fibrocartilage within the zonal tendon-to-bone enthesis [1-4]. However, whether this pathway has a similar role in adult zonal tendon-to-bone repair is not known. Therefore, we developed a murine anterior cruciate ligament (ACL) reconstruction model [5] to better understand the zonal tendon-to-bone repair process and perturb key developmental regulators to determine the extent to which they can promote successful repair in the adult. In doing so, we activated the hedgehog signaling pathway both genetically using transgenic mice and pharmacologically via agonist injections. We demonstrated that both treatments improved the formation of zonal attachments and tunnel integration strength [6]. These improved outcomes were due in part to hedgehog signaling's positive role in proliferation of the bone marrow stromal cell (bMSC) progenitor pool and subsequent fibrocartilage production of bMSC progeny cells that form the attachments. These results suggest that, similar to growth and development, hedgehog signaling promotes the production and maturation of fibrocartilage during tendon-to-bone integration in adults. Lastly, we developed localized drug delivery systems to further improve the treatment of these debilitating injuries in future translational studies. Acknowledgements: This work was supported by NIH R01AR076381, R21AR078429, R00AR067283, F31AR079840, T32AR007132, and P30AR069619, in addition to the McCabe Fund Pilot Award at the University of Pennsylvania