Hans Van Der Bracht

Revising the Well-Fixed, Painful Resurfacing Using a Double-Mobility Head: A New Strategy to Address Metal-on-Metal Complications

Isolated revision of the femoral component of hip resurfacings to metal-on-metal (MoM) total hip arthroplasties has shown inferior results. We present a case series of well-fixed, painful MoM hips with elevated chromium and cobalt levels. An isolated femoral revision using a noncemented femoral component and a double-mobility head was performed. Patients were followed up for 6 months and showed excellent improvements in visual analog score and Hip dysfunction and Osteoarthritis Outcome Score (HOOS). Cobalt and chromium levels dropped at 6 weeks and were normal at 6 months. Although our follow-up is short, we feel that it is important to highlight this as a potential treatment strategy. This revision is less aggressive than traditional methods, eliminates the concerns from MoM bearings, and results in a stable construct.

The lateral tibial tunnel in revision anterior cruciate ligament surgery: a biomechanical study of a new technique

PURPOSE To evaluate the cortical entry point and the length of a revision lateral tibial tunnel (LTT) in a human cadaveric study and to investigate knee stability after a revision anterior cruciate ligament (ACL) reconstruction with an LTT. METHODS Ten human cadaveric knee specimens were used to perform a preliminary investigation. Twenty-two human proximal tibias were used to compare the length of a revision LTT with a classical medial tibial tunnel (MTT). Another 5 human cadaveric knees were used to investigate knee stability after a revision LTT and to compare it with a primary ACL repair with an MTT performed in the same knees. Stability was evaluated with computer navigation. RESULTS An LTT is statistically significantly longer (45.0 mm) than an MTT (35.2 mm) (P < .001). There was no evidence of a length difference between the intact bone tube length of a revision LTT (36.5 mm) and an MTT. For nearly all measurements, the difference between the ACL repair with an MTT and the revision surgery with an LTT was not only nonsignificant but also small in magnitude. Only for internal rotation at 30° of knee flexion and for internal rotation in extension was a significant difference detected (P = .029 and P = .044, respectively). CONCLUSIONS An LTT can easily be drilled and provides a bony tunnel that is statistically significantly longer than an MTT. A revision LTT has an intact bone tube as long as that of a primary MTT. Similar stability is obtained after revision ACL surgery with an LTT compared with a primary ACL repair with a standard MTT. CLINICAL RELEVANCE LTT placement is a new technique for ACL revision surgery that can help to overcome problems related to tunnel enlargement in the distal part of the tibial tunnel.

Custom-made lateral femoral hemiarthroplasty for traumatic bone loss: A case report

We report the case of a 32-year-old male patient involved in a road traffic accident in which he sustained a grade II open supra- and intercondylar fracture of the left distal femur with substantial bone loss of the lateral femoral condyle and trochlea (AO classification type 33 C3). Normal knee function was no longer possible, as the patella was trapped within the bony defect. Existing reconstructive options such as unicondylar osteoarticular allograft, arthrodesis, and arthroplasty were considered. However, as all these techniques present significant disadvantages, particularly in young and active patients, a custom-made lateral hemiarthroplasty was designed and implanted as an alternative treatment. Follow-up at 24 months revealed an excellent, pain-free level of function and radiographs showed no signs of implant loosening or migration. This technique offers the most anatomical means of reconstruction with maximal preservation of the bone stock, thereby better facilitating any revisions that may be necessary in the future. This is an experimental technique reserved for rare indications, and currently has no long-term follow-up results associated with its use. Additional research is therefore needed before widespread adoption of this technique can take place.

Peak stresses shift from femoral tunnel aperture to tibial tunnel aperture in lateral tibial tunnel ACL reconstructions: a 3D graft-bending angle measurement and finite-element analysis

PurposeTo investigate the effect of tibial tunnel orientation on graft-bending angle and stress distribution in the ACL graft.MethodsEight cadaveric knees were scanned in extension, 45°, 90°, and full flexion. 3D reconstructions with anatomically placed anterior cruciate ligament (ACL) grafts were constructed with Mimics 14.12®. 3D graft-bending angles were measured for classic medial tibial tunnels (MTT) and lateral tibial tunnels (LTT) with different drill-guide angles (DGA) (45°, 55°, 65°, and 75°). A pivot shift was performed on 1 knee in a finite-element analysis. The peak stresses in the graft were calculated for eight different tibial tunnel orientations.ResultsIn a classic anatomical ACL repair, the largest graft-bending angle and peak stresses are seen at the femoral tunnel aperture. The use of a different DGA at the tibial side does not change the graft-bending angle at the femoral side or magnitude of peak stresses significantly. When using LTT, the largest graft-bending angles and peak stresses are seen at the tibial tunnel aperture.ConclusionIn a classic anatomical ACL repair, peak stresses in the ACL graft are found at the femoral tunnel aperture. When an LTT is used, peak stresses are similar compared to classic ACL repairs, but the location of the peak stress will shift from the femoral tunnel aperture towards the tibial tunnel aperture. Clinical relevance: the risk of graft rupture is similar for both MTTs and LTTs, but the location of graft rupture changes from the femoral tunnel aperture towards the tibial tunnel aperture, respectively.Level of evidenceI.