Erhan Basad

Evaluation of implant position and knee alignment after patient-specific unicompartmental knee arthroplasty

Implant positioning and knee alignment are two primary goals of successful unicompartmental knee arthroplasty. This prospective study outlines the radiographic results following 32 patient-specific unicompartmental medial resurfacing knee arthroplasties. By means of standardized pre- and postoperative radiographs of the knee in strictly AP and lateral view, AP weight bearing long leg images as well as preoperative CT-based planning drawings an analysis of implant positioning and leg axis correction was performed.The mean preoperative coronal femoro-tibial angle was corrected from 7° to 1° (p<0.001). The preoperative medial proximal tibial angle of 87° was corrected to 89° (p<0.001). The preoperative tibial slope of 5° could be maintained. The extent of the dorsal femoral cut was equivalent to the desired value of 5mm given by the CT-based planning guide. The mean accuracy of the tibial component fit was 0mm in antero-posterior and +1mm in medio-lateral projection. Patient-specific fixed bearing unicompartmental knee arthroplasty can restore leg axis reliably, obtain a medial proximal tibial angle of 90°, avoid an implant mal-positioning and ensure maximal tibial coverage.

Fatigue Fracture of a Short Stem Hip Replacement: A Failure Analysis With Electron Microscopy and Review of the Literature

Four years after primary implantation of an ESKA Cut short-stemmed prosthesis, a 61-year-old patient suffered fracture of the implant. The combination of missing proximal support of the prosthesis as well as enormous strain on the distal third of the stem can be considered as main reason for the fatigue failure. The special design of the modular implant with a small diameter and a spongy metal surface can be regarded as a contributing factor. This unique case demonstrates a possible failure mechanism of short- and ultra short-stemmed prostheses.

The Anterolateral Minimally Invasive Approach for Total Hip Arthroplasty: Technique, Pitfalls, and Way Out

Different approaches for the hip have been developed for minimally invasive surgery in total hip arthroplasty. The goal of minimally invasive surgery is to reduce invasiveness to skin, muscles, and bone and improve recovery time after total hip arthroplasty. This article describes the technique of a minimally invasive approach to the hip from the anterolateral direction step by step and includes preoperative settings and pitfalls.

Treatment of Chondral Defects by Matrix-Guided Autologous Chondrocyte Implantation (MACI)

Articular cartilage is not capable of self-repair. Traumatic damages are one of the most common causes of the premature onset of osteoarthritis. Cartilage is avascular and therefore regeneration is different compared to wound healing in tissues with an extensive blood supply [6, 9]. Currently, stimulating (microfracture, Pridie-drilling, and abrasion arthroplasty) and reparative techniques (mosaicplasty, ACT, MACI, perichondrium- and periosteal flap transplantation) are available for surgical treatment of cartilage defects. Using stimulating techniques a fibrocartilage is formed. In these techniques the subchondral bone plate in the area of the cartilage defect has to be penetrated and mesenchymal progenitor cells are recruited from the bone marrow.

Arthroscopic Primary Repair of Fresh Partial ACL Tears

Fresh subtotal ACL tears have been reported to have the ability to heal with the help of subchondral bleeding spontaneously or by provoked bleeding in the avulsion of the notch. Within an orienting prospective study, 55 fresh partial (50–80%) ACL injuries were treated with arthroscopic primary repair to demonstrate the effect of provoked healing. The torn ACL bundles were re-adapted and the anatomical onsets at the bone were perforated in order to provoke a healing response from a super clot with mesenchymal stem cells. If re-insertion and reduction was difficult, an additional arthroscopic fixation with a suture anchor had to be performed. The knee rehabilitation was performed mainly in extended position and limited range of motion within the first 3 weeks, providing unloading for the ACL. Clinical and MRI follow-ups were performed at 6, 12, and 24 months. The median Tegner activity score performed from 2 to 5 points after 24 months. The mean Lysholm knee-score improved from 41 to 92 points after 24 months. The MRI showed morphological changes, with unorganized ligament fibers changing to continuous end-to-end appearance – mostly with a normal thickness and with hypertrophy or atrophy in a few cases. The KT-1000 measurement showed an improvement in stability from 3.4 to 2 mm mean value. Eleven (17%) cases showed failures within the first 12 months with inadequate stability (four) or recurrent trauma (seven) during sports activity. In mid-term time response, arthroscopic primary repair is a minimally invasive, easy, and inexpensive procedure that shows an 83% success rate if applied in fresh partial ACL tears.