Aim

Mesenchymal stem cells (MSCs) have several properties that may support their use as an early treatment option for osteoarthritis (OA). This study investigated the role of multiple injections of allogeneic bone marrow-derived stem cells (BMSCs) to alleviate the progression of osteoarthritic changes in the various structures of the mature rabbit knee in an anterior cruciate ligament (ACL)-deficient OA model.

Aims

To investigate the risk factors for progression of articular cartilage damage after anatomical anterior cruciate ligament (ACL) reconstruction.

We report the clinical outcome and findings at second-look arthroscopy of 216 patients (mean age 25 years (11 to 58)) who underwent anterior cruciate ligament (ACL) reconstruction or augmentation. There were 73 single-bundle ACL augmentations (44 female, 29 male), 82 double-bundle ACL reconstructions (35 female, 47 male), and 61 single-bundle ACL reconstructions (34 female, 27 male).

In 94 of the 216 patients, proprioceptive function of the knee was evaluated before and 12 months after surgery using the threshold to detect passive motion test.

Second-look arthroscopy showed significantly better synovial coverage of the graft in the augmentation group (good: 60 (82%), fair: 10 (14%), poor: 3 (4%)) than in the other groups (p = 0.039). The mean side-to-side difference measured with a KT-2000 arthrometer was 0.4 mm (-3.3 to 2.9) in the augmentation group, 0.9 mm (-3.2 to 3.5) in the double-bundle group, and 1.3 mm (-2.7 to 3.9) in the single-bundle group: the result differed significantly between the augmentation and single-bundle groups (p = 0 .013). No significant difference in the Lysholm score or pivot-shift test was seen between the three groups (p = 0.09 and 0.65, respectively). In patients with good synovial coverage, three of the four measurements used revealed significant improvement in proprioceptive function (p = 0.177, 0.020, 0.034, and 0.026).

We conclude that ACL augmentation is a reasonable treatment option for patients with favourable ACL remnants.

Cite this article: Bone Joint J 2014;96-B:1325–32

We examined whether enamel matrix derivative (EMD) could improve healing of the tendon–bone interface following reconstruction of the anterior cruciate ligament (ACL) using a hamstring tendon in a rat model. ACL reconstruction was performed in both knees of 30 Sprague-Dawley rats using the flexor digitorum tendon. The effect of commercially available EMD (EMDOGAIN), a preparation of matrix proteins from developing porcine teeth, was evaluated. In the left knee joint the space around the tendon–bone interface was filled with 40 µl of EMD mixed with propylene glycol alginate (PGA). In the right knee joint PGA alone was used. The ligament reconstructions were evaluated histologically and biomechanically at four, eight and 12 weeks (n = 5 at each time point). At eight weeks, EMD had induced a significant increase in collagen fibres connecting to bone at the tendon–bone interface (p = 0.047), whereas the control group had few fibres and the tendon–bone interface was composed of cellular and vascular fibrous tissues. At both eight and 12 weeks, the mean load to failure in the treated specimens was higher than in the controls (p = 0.009). EMD improved histological tendon–bone healing at eight weeks and biomechanical healing at both eight and 12 weeks. EMD might therefore have a human application to enhance tendon–bone repair in ACL reconstruction.

We have investigated the changes in anterior laxity of the knee in response to direct electrical stimulation of eight normal and 45 reconstructed anterior cruciate ligaments (ACLs). In the latter, the mean time from reconstruction was 26.7 months (24 to 32). The ACL was stimulated electrically using a bipolar electrode probe during arthroscopy. Anterior laxity was examined with the knee flexed at 20° under a force of 134 N applied anteriorly to the tibia using the KT-2000 knee arthrometer before, during and after electrical stimulation.

Anterior tibial translation in eight normal and 17 ACL-reconstructed knees was significantly decreased during stimulation, compared with that before stimulation. In 28 knees with reconstruction of the ACL, in 22 of which the grafts were found to have detectable somatosensory evoked potentials during stimulation, anterior tibial translation was not decreased. These findings suggest that the ACL-hamstring reflex arc in normal knees may contribute to the functional stability and that this may not be fully restored after some reconstructions of the ACL.

A total of 108 patients with unilateral instability of the knee, associated with rupture of the anterior cruciate ligament, was prospectively randomised for arthroscopic single- or double-bundle reconstruction of the ligament using hamstring tendons. The same postoperative rehabilitation protocol was used for all. The patients were followed up for a mean of 32 months (24 to 36). We measured the anterior laxity and joint position sense at different angles of flexion of the knee to determine whether both bundles in the double-bundle reconstruction contributed to the stability of the joint and proprioception.

No significant difference was found between the two groups with regard to anterior laxity measured by the KT-2000 arthrometer with the knee at 20° or 70° flexion nor with regard to proprioception. A notchplasty was required less often in the double- compared with the single-bundle reconstruction.

We did not find any advantage in a double-bundle as opposed to a single-bundle reconstruction in terms of stability or proprioception.

We investigated the clinical, arthroscopic and biomechanical outcome of transplanting autologous chondrocytes, cultured in atelocollagen gel, for the treatment of full-thickness defects of cartilage in 28 knees (26 patients) over a minimum period of 25 months. Transplantation eliminated locking of the knee and reduced pain and swelling in all patients. The mean Lysholm score improved significantly. Arthroscopic assessment indicated that 26 knees (93%) had a good or excellent outcome. There were few adverse features, except for marked hypertrophy of the graft in three knees, partial detachment of the periosteum in three and partial ossification of the graft in one. Biomechanical tests revealed that the transplants had acquired a hardness similar to that of the surrounding cartilage. We conclude that transplanting chondrocytes in a newly-formed matrix of atelocollagen gel can promote restoration of the articular cartilage of the knee.

For the purpose of investigating the effect of an insole with a lateral wedge, we studied 30 patients (31 knees) aged from 46 to 78 years with idiopathic osteonecrosis of the knee for at least three years. The 18 knees treated with an insole (group I) were matched by age, gender, obesity index, area of lesion, femorotibial angle, stage, and clinical evaluation with 13 treated conservatively without an insole (group II).

The clinical results, as rated by a knee score, improved significantly more in group I than in group II. Radiologically, the necrotic area and ratio decreased in group I, whereas in group II they increased. In advanced cases, with stage 4 or a femorotibial angle of more than 180°, the use of an insole did not improve the clinical or radiological findings. The insole is a valuable method of conservative treatment for the early stages of osteonecrosis of the medial femoral condyle.