Aim: Cementation of tibial implants in total knee arthroplasty is a gold-standard considering the high loosening rates of cementless implants. In contrast, only sparse data exist regarding unicondylar arthroplasty due to limited use. In this study, we compare cemented with cementless unicondylar knee arthroplasty and aim to define both clinical and radiological differences in treatment outcome.

Materials and Methods: In a retrospective study, 106 patients who had undergone a medial unicondylar replacement were examined after a mean postoperative period of 8 years. Of these, 42 patients (median age 81±7 years) had received a cemented and 64 (median age 73±7 years) a cementless knee arthroplasty by the same surgeon while 7 patients were deceased or could not be reached. Well-established clinical (VAS, HSS, KSS, UCLA, WOMAC) and quality of life (SF-36) scores were used to evaluate treatment outcome. X-rays were performed to evaluate periprosthetic loosening zones, according to Ewald’s criteria.

Results: The cementless patient group presented significantly better clinical scores (HSS, KSS, UCLA, WOMAC), except in the Visual Analogue Scale (VAS) for pain assessment. The quality of life was significantly better in the cementless group except in the subgroups concerning physical function, vitality and social role, which resembled normal population. Moreover, radiographic analysis using antero-posterior X-rays revealed significantly more and larger periprosthetic loosening areas in tibial zone 2 in the cementless group.

Conclusion: The inferior clinical results characterising the cemented group could be attributed to the higher mean age. Regarding the radiological loosening zones, we did not detect any differences in the techniques of fixation, although physical activity and mechanical stresses were higher in the cementless group.

Rotational instability is defined as combined medial and lateral ligament instability of the ankle joint. In the case of combined injury to the posterior syndesmosis and posterior joint portion the typical giving-away-symptoms and the therapy resistant complaints are accompanied. In the following prospective study 43 patients between the ages of 16 and 35 with the average age of 23.9 years with posttraumatic chronic joint-instability as well as posterior syndosmosis insufficiency were examined.

The treatment of rotational instability was performed by an anchoring technique modified by Broström. The resulting insufficiency of the posterior syndesmosis was treated by a Tight Rope provided by Arthrex.

The study was run over 14 months, where only 36 out of 43 patients were available for postoperative follow up. A preoperative baseline 2-view x-ray as well as an MRI was performed in all patients. The operation to establish the stability of the ligaments via anchoring-technique and the treatment of the posterior syndesmosis through Tight-Rope were performed via arthroscopy of the ankle joint with additional inspection of the posterior joint portion. At the same time existent impingements were recessed. In each patient the AOFAS score as an indicator for the treatement outcome and the VAS-score was used as the measurement for the level of pain developement were used.

The first exam was performed in preoperative setting followed by subsequent 12 and 24 weeks as well as 12 and 14 months postoperatively. To ensure stability a preoperative x-ray in suppination stress was performed followed by the same type of x-ray 3 months postoperatively. A significant improvement in the above mentioned scores were noted already 3 months after the operation. An improvement in VAS-score of 5.1 points as well as in AOFAS-score of 79% was observed. The degree of Suppination and rotational movement as well as the extent of talus-forfall has reduced significantly. The already improvement of the above scores after 3-month-follow up were consistent even after 14 months. About 90% of patients were satisfied with the outcome of the operation with the “good” and “very good” scores. The complication rate was about 3%.

In conclusion, the treatment of posttraumatic mechanical ankle joint instability with posterior syndesmosis injury via anatomic anchoring reconstructive technique and Tight-Rope is considered to be an operative modality with significantly satisfactory results.

Keywords: Rotational instability, posterior syndesmosis, stabilisation, tight-rope