Purpose of study and background

Mechanical overloading initiates intervertebral disc degeneration, presumably because cells break down the extracellular matrix (ECM). We used Fourier Transform Infrared Spectroscopy (FTIR) imaging to identify, visualize and quantify the ECM and aimed to identify spectroscopic markers for early disc degeneration.

Biomechanical overloading initiates intervertebral disc degeneration. We hypothesized that this is due to mechanosensitivity of the cells, which break down the extracellular matrix. Previously, we found that overloading in a loaded disc culture system causes upregulation of remodeling- and inflammatory gene expressions. Fourier Transform Infrared Spectroscopy is a novel technique to identify, visualize and quantify ECM. In this research, we first identified novel spectroscopic markers for disc degeneration, and then applied these markers to investigate the first steps into disc degeneration by overloading.

In dataset 1, 18 discs of 9 goats were injected with chondroitinase ABC (degenerated) or not (control), and obducted 3 months after injection. This was used to find new spectroscopic markers for degeneration. In dataset 2, 42 goat discs were loaded with a physiological loading regime (50–150N) or overloading (50–400N) in a loaded disc culture system. In 18 of these discs, the cell activity was diminished in advance by freeze-thaw cycles and culturing on saline alone (non-vital group)). 24 additional discs were cultured in culture medium immediately post-mortem (vital group). Thereby, we are able to control whether the effect of the overloading is due to cell activity. The discs were fixed in formaldehyde, and 4 μm mid-sagittal were mounted to steel reflectance slides. Infrared spectroscopic mosaic images (23 × 57 images) were collected in transflectance mode at a spectral region of 1025–1150 cm⁻¹. Data was pre-processed by second derivative transformation and MCR-MALS with two factors.

The two factors were transferable between datasets, confirming the reliability. The first factor represents proteoglycans, as confirmed by Saffrin-O staining. In dataset 1, the degenerated group had less proteoglycan factor overall, especially in the nucleus (p<0.05). The second factor was found to have a lower entropy (p<0.01), showing a disorganization in the matrix. In dataset 2, no significant reduction in proteoglycan was found due to overloading in any group. However, the entropy was lower in the overloaded vital group (p<0.05), but not in the overloaded non-vital group (p>0.5).

Therefore, we conclude that infrared spectroscopy is a promising tool to investigate early disc degeneration. Overloading can cause changes in the extracellular matrix, but only due to cell activity. Entropy is an early marker for early disc degeneration, implying that cutting of the extracellular matrix by cell activity is the first step into intervertebral disc degeneration.

Introduction: Drilling of the femoral bone tunnel in anterior cruciate ligament reconstruction may be performed in a transtibial drilling technique or via the anteromedial portal.

Purpose: To determine the accuracy of the radiographic bone tunnel position using either a transtibial or anteromedial drilling technique.

Materials & methods: The postoperative lateral radiographs of 100 patients after anterior cruciate ligament reconstruction were reviewed. In each patient, the femoral bone tunnel was created either through the tibial tunnel or via the anteromedial standard arthroscopy portal. The resulting position of the femoral tunnel was evaluated according to reference values reported by Aglietti (65 % of the cortical femoral A-P distance along Blumenstaat’s line), Amis (60 % of the A-P diameter of the posterior lateral femoral condyle parallel to Blumensaat’s line), and Harner (80 % of the A-P length of Blumensaat’s line). The mean deviation of the radiographic tunnel position from the referenced values was statistically evaluated.

Results: Radiographic bone tunnel positions with transtibial drilling were 62.42 ± 8.36, %, 54.53 ± 8.43 %, and 75.84 ± 9.56 % according to Aglietti, Amis, and Harner, respectively. Bone tunnel positions with anteromedial drilling were 65.46 ± 5.29 %, 59.59 ± 4.18 %, and 79.93 ± 4.24 %, respectively. The mean deviation from the reference values was significantly higher when comparing transtibial to anteromedial drilling. Transtibial drilling resulted in a significantly more anterior bone tunnel position.

Conclusion: Precise bone tunnel placement is a prerequisite for proper postoperative knee function and stability. The results of this study indicate that the accuracy of femoral bone tunnel placement through the anteromedial arthroscopy portal was superior to transtibial drilling. It may therefrore be concluded that drilling the femoral tunnel through the anteromedial portal is recommended when using fixation techniques not depending upon placement of a transtibial guide.

Background: The influence of the knee angle on plantarflexion moments after Achilles tendon repair has yet to be analyzed. It was hypothesized that flexion of the knee joint will disproportionately influence isometric plantarflexion moments after Achilles tendon repair.

Methods: Isometric plantarflexion moments and functional heel rise performance were retrospectively assessed in 32 patients at a mean follow-up of 36.9 (±17.83) months after open or percutaneous repair of acute Achilles tendon rupture. Plantarflexion moments were measured with the knee joint in 0, 30, and 60 degrees of flexion and the ankle joint positioned in neutral, 15 degrees plantar flexion and 15 degrees dorsiflexion. Data were compared between the involved and the noninvolved leg as well as between open and percutaneous repair.

Results: Flexion of the knee had no significant effect on isometric plantarflexion moments in either the involved or the noninvolved leg, while at any knee angle, plantarflexion moments decreased from dorsiflexion to plantar flexion. In accordance, dynamic heel rise performance revealed no significant strength deficits between the involved and the noninvolved limb. No overall differences in plantarflexion strength were observed between open and percutaneous Achilles tendon repair.

Conclusions: The flexion angle of the knee had no influence on plantarflexion moments when comparing the involved with the noninvolved leg after open or percutaneous Achilles tendon repair. Weakness of plantarflexion after open or percutaneous Achilles tendon repair is determined by the position of the ankle joint rather than by the flexion angle of the knee.

Background: To correct deformity and achieve fusion after failed fusion a retrograde nail with posterior-to-anterior (PA) locking into os calcis, talus and tibia was used.

Methods: A variety of Methods: have been published to achieve union of the ankle and subtalar joint in a failed fusion situation. We have studied a retrograde locking nail technique through a 2.5 cm incision in the non-weigthbearing part of the sole of the foot. Remaining cartilage in the ankle joint, where necessary, was percutaneously removed through an anterior approach and the locking nail was inserted after reaming of os calcis, talus and tibia. Locking screw insertion was in the sagittal plane (p.a. direction), in talus os calcis and tibial diaphysis using a nail mounted jig. Ten patients were entered in the study (age 27–60 years). The initial aetiology for attempted fusion was posttraumatic in nine cases and rheumatic in one case. There were 25 previous operations in the cohort not leading to fusion. An additional temporary external fixator was used in four cases to reach and maintain the optimum position for the procedure. The intervention time was 30–75 minutes. Dynamization of the nail was performed after four months under local anaesthesia.

Results: The mean duration of follow-up was 4 years (3 to 5,5 years). Radiologically and clinically, fusion was achieved in 16 weeks (range, 12 to 20 weeks). There was no loosening of the implant nor implant failure. A leg length discrepancy was avoided using this technique. There was one complication with varus malunion in a heavy smoker which united after corrective osteotomy, revision nailing and bone grafting. Patient satisfaction was measured on a scale (not visual analog) of 0 (not satisfied) to 10 (completely satisfied), overall satisfaction averaged 9.5 points (range, 6 to 10 points). The postoperative ankle-hindfoot score of the American Orthopedic Foot and Ankle Society averaged 73,5 points (range, 61 to 81 points).

Conclusion: Retrograde locked nailing with locking in the sagittal plane is a reliable minimally invasive procedure to achieve fusion of the ankle and the subtalar joint after failed fusion.