Objective To explore the biomechanic effects of multi ple freeze-thaw on human allograft tendons. Methods Thirty tendons (24 flexor digitorum superficial is tendons and 6 flexor poll icis longus tendons) were harvested from 3 fresh cadaver donors and were divided into 6 groups randomly (fresh group; 1 cycle, 2 cycle, 3 cycle, 5 cycle, and 10 cycle freeze-thaw groups). There was 4 flexor digitorum superficial is tendons and 1 flexor poll icis longus tendon in each group. The structural and mechanical properties as well as viscoelastic change were estimated. Results The results of the structural and mechanical properties in 1 cycle, 2 cycle, and 3 cycle freeze-thaw groups were similar to that of the fresh group (P gt;0.05). The tendons in 5 cycle and 10 cycle freeze-thaw groups showed a significantly lower ultimate load and maximum stress when compared with those of fresh group (P lt; 0.05), but there was no significant difference in maximum tensile or maximum strain (P gt; 0.05). Moreover, the tendons in 5 cycle and 10 cycle freeze-thaw groups had a significant increase in viscoelastic properties when compared with fresh group (P lt; 0.05). Conclusion In the cryopreservation of tendon allografts, the cycle of freeze-thaw should not exceed 3 times. Multiple cycle freeze-thaw will weaken the biomechanical properties of tendon allografts, which make grafts easier to fatigue or even rupture.
Objective To investigate the cl inical therapeutic results of allograft tendon for anatomical reconstruction of medial patellofemoral l igament (MPFL) in patellar dislocations. Methods From September 2005 to June 2008, 20 patientswith patellar dislocation underwent MPFL reconstructions. There were 4 males and 16 females, aged 13 to 31 years (19 years on average). Patellar dislocations occurred in 7 left and 13 right knees, including 6 cases of acute dislocation and 14 cases of recurrent dislocation. The disease course was 1 day to 2 years. The frequency of dislocation was 1-6 (4 on average). Affected knee joint showed pain, swell ing and patellar instabil ity; the range of action for patella obviously increased. The X-ray films showed patellar dislocation or medial margin avulsion fracture. The preoperative Q angle was (15 ± 3)°, the congruence angle was (10 ± 11)°. Reconstruction was performed via allograft tendon. Allograft tendon was anchored to the superomedial pole of the patella by two bone anchors, and the other end was fixed at the natural MPFL insertion site near the medial femoral condyle with an interference screw in a bone tunnel. All patients were evaluated postoperatively; Kujala patellofemoral scores, objective knee function, compl ications, and reoperations were assessed. Results Primary heal ing was achieved in 18 cases and secondary heal ing in 2 cases. No infection or necrosis and absorption of grafts was observed. All patients were followed up for an average of 25.6 months (range, 6-34 months) postoperatively. At last follow-up, other patients had no pain, swell ing and patellar instabil ity except 1 case; neither patella redislocation nor fracture occurred. The X-ray films showed good position of anchors and tunnel 6 months after operation, and the congruence angle was (3 ± 8)°, showed statistically significant difference when compared with preoperation (P lt; 0.05). The postoperative Q angle was (15 ± 2)°, the Kujala knee function score improvedsignificantly from 60.8 ± 7.2 to 83.4 ± 8.0 at last follow-up, showing statistically significant difference (P lt; 0.05). According to Insall et al. for function, the results were excellent in 12 cases, good in 6 cases, and fair in 2 cases, the excellent and good rate was 90%. Conclusion MPFL reconstruction improves cl inical symptoms. Anatomical MPFL reconstruction is effective for patellar dislocation, and it offer good recovery of the pre-morbid patella mechanics. There would be l ittle bone loss when tendon is fixed by anchors, and there would be less patellar fracture than bone tunnel technique. The bone anchors also provide firm fixation. Allograft can avoid the graft harvest site morbidity, but it increases the cost of the surgery.
To research the operative method and the cl inical efficacy of repairing and reconstructing tendon and l igament with allograft tendon. Methods From September 2000 to May 2007, 164 cases with tendon and l igament injuries were treated, including 116 males and 48 females aged 21-47 years old (average 31.5 years old). There were 126 cases of anterior cruciate l igament injury, 18 cases of complete acromioclavicular dislocation, 10 cases of old dislocation of radialhead, 4 cases of Achilles tendon rupture, 2 cases of tibial is anterior muscle rupture, 2 cases of patellar tendon rupture, and 2 cases of rectus femoris rupture. Time interval between injury and hospital admission was 4-345 days (average 75 days). Allograft tendon 10-26 cm in length with suture anchor or absorbable interference screw was used to reconstruct the l igament and tendon. Results All wounds healed by first intention, except one case of rectus femoris rupture. All patients were followed for 10-36 months (average 21 months). The international knee documentation commitee and the Lysholm score of patients with anterior cruciate l igament injury 12 months after operation were significantly higher than that of before operation (P lt; 0.01). According to the Lazzcano and Karlsson score standard, 13 cases of complete acromioclavicular dislocation at 10-12 months after operation were graded as excellent and 5 cases were good. According to Arner Lindholm score standard, 3 cases of Achilles tendon rupture at 8-16 months after operation were graded as excellent and 1 case was good. For the patients with tibial is anterior muscle rupture, at 10-17 months after operation, the limitation of dorsal extension in ankle joint was 5°, and the muscle strength in the anterior tibial is muscle was decreased. For the patients with patellar tendon rupture, one completely restored the motion range of the knee joint 14 months after operation, the other had knee extension l imitation of 10° at 13 months after operation. For the patients with rectus femoris rupture, one had 15° of extension limitation at 18 months after operation, the other suffered limitation of both extension and genuflex at 12 months after operation. According to the Broberg-Morrey score standard, 7 caseswith old dislocation of radial head were graded as excellent and 3 cases were good at 3-36 months after operation. Conclusion Allograft tendon is a good material for repairing and reconstructing tendon and ligament injuries, but attention should be paid to postoperatively early exercise under appropriate protection and early management of local rejection.
ObjectiveTo systematically review the efficacy of hamstring tendon autograft versus hamstring tendon allograft in anterior cruciate ligament reconstruction by arthroscopy. MethodsDatabases including PubMed, EMbase, The Cochrane Library (Issue 2, 2015), CNKI, VIP, WanFang Data were electronically searched to collect randomized controlled trials (RCTs) about hamstring tendon autograft versus hamstring tendon allograft in anterior cruciate ligament reconstruction by arthroscopy from inception to February 2015. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed using RevMan 5.2 software. ResultsA total of 6 RCTs involving 535 knees were included. The results of meta-analysis showed that:(1) Postoperative physical outcomes:There were no significant differences between the hamstring tendon autograft group and the hamstring tendon allograft group in positive rate of Lachman test (RR=1.25, 95%CI 0.92 to 1.71, P=0.15) and positive rate of Pivot shift test (RR=1.04, 95%CI 0.93 to 1.17, P=0.47) at 1 year postoperatively. (2) Postoperative functional recovery outcomes:There were no significant differences between both groups in KT-1000/2000 measurement (MD=-0.79, 95%CI -1.78 to 1.20, P=0.12), abnormal rate of IKDC scores (RR=1.03, 95%CI 0.90 to 1.1, P=0.42) and Lysholm scores (MD=0.23, 95%CI -1.86 to 2.33, P=0.83) at 1 year postoperatively. ConclusionHamstring tendon autograft and hamstring tendon allograft have similar efficacy in anterior cruciate ligament reconstruction by arthroscopy. Due to limited quality and quantity of the included studies, more large-scale and high quality studies are needed to verify the above conclusion.