BACKGROUND

Despite many years of clinical experience the optimal bearing choice in total hip arthroplasty (THA) remains controversial. This study aims to directly compare the three widely used bearing surfaces: metal-on-highly crosslinked polyethylene (MoHXLPE), ceramic-on-ceramic (CoC) and metal-on-metal (MoM), regarding clinical and radiologic outcome parameters.

Background: Recently, the new phenomenon of “squeaking” noises emitted from THAs with ceramic-onceramic bearings has spared international interest. It shows a frequency of 0,7–19,5% in literature, but infrequently requires revision surgery. However, an even higher incidence of various other noises from those THAs audible to the human ear have become popular in the process: this noise can resemble clicking, grinding or creaking and can be caused by distinct movements, during longer periods of walking, or can be constant with movement. The incidence of those noises can reach up to 30% of THAs. However, memory has faded that other bearings like metal-on-metal and PE/ceramic have been associated with noises in the past.

Therefore we aimed to investigate the occurence of acoustic emissions in patients, who had all received the same implant but with alternate bearings, to investigate the nature of noise, duration and clinical consequence for all 3 bearings (polyethylene/ceramic, metalon-metal, ceramic-on-ceramic).

Method: Between 1999–2001, 360 patients were matched in a prospective randomised trial. All of them received a cementless Zimmer© Alloclassic Variall™ implant at the Orthopaedic Hospital Vienna – Speising, Austria with either a ceramic-on-ceramic bearing, a metal-on-metal bearing or a polyethylene/ceramic bearing. A questionnaire was sent via mail, including questions on first occurence of hip noise, information on the kind and duration of the phenomenon and possible adverse evaluation on behalf of the patient. In case of a positive report, the patient was invited to a clinical examination and radiographic analysis. In addition, a specialised audiography was conducted in patients with audible sensations. Finally, the SF-36 and WOMAC were analysed. A number of patients received further examination with methods of gait analysis in order to detect the distinct point of occurence of the noise during the gait cycle.

Results: 33 patients reported an audible phenomenon from their THA, 14 received a ceramic-onceramic bearing (Cerasul), 13 a polyethylene/ceramic bearing (Durasul) and 6 a metal-onmetal bearing (Metasul). The most common noise was a distinct clicking, followed by a creaking noise. Only 1 patient reported a squeaking sensation, he received a polyethylene/ceramic bearing.

Conclusion: The emission of specific noises from THAs of all bearings has been well documented in recent trials and could be verified in this survey of cementless THAs. No trend towards an increased incidence of noise from THAs with ceramic-on-ceramic bearings could be detected. Interestingly, the single case of „squeaking” was reported from a patient with polyethylene/ceramic bearing. Microseparation and subluxation of the femoral head with resulting edge loading and formation of stripe wear has recently been suspected as the main cause for “noisy hips.” So far 2 ceramic-on-ceramic hips of this study group population have been revised. Both articulations showed areas of stripe wear due to subluxation of the joint.

Purpose: The difficulty of successive reconstructions of the anterior cruciate ligament (ACL) using an autologous graft depends on many factors. The choice of the new transplant is crucial. The purpose of this study was to assess outcome in 17 patients who underwent successive repairs of the ACL after failed patellar tendon graft where the same patellar ligament site was used to harvest the graft. This choice resulted from the width of the existing bone tunnels (irrespective of the type of screw used) that were often correctly positioned by contraindicated a relatively narrow transplant.

Material and method: The graft was obtained from the patellar ligament at the same site as used for the primary repair in 19 patients. The graft was medialised so half of the fibres were cicatricial and half were tendon with bone prolongations. Arthroscopy revealed a lesion of the distal portion of the transplant near the tibial inertion in nine cases, a proximal lesion in five cases and distension in five cases. Five patients had also had a contralateral plasty of the ACL. Mean age was 31 years. Symptoms included instability, alone or with pain. In 12 cases, partial meniscectomy was performed before or during the repeat plasty procedure. Minimum follow-up was one year for 17 patients with a mean of 21 months. IKCD and Lysholm-Tegner criteria were assessed. Laxity was measured at maximal manual traction using a KT 1000.

Results: Overall IKDC outcome was 2A, 10B, 4C, and 1D. Differential laxity at maximal manual traction, evaluated for the 12 patients with a healthy contralateral knee was 2.7 ± 1.3 mm (versus 1.7±1.9 mm in the control series). Mean pre-postoperative gain in the 17 patients was 5.4 ± 3 mm (versus 5.6 ± 2.4 mm in the control series). The predominant sign was residual pain (11/17). Pain was generally moderate and induced by exercise. Pain at the site of graft harvesting was frequent during the six months after surgery (11 cases) but rare after one year (2 cases).

Discussion: Due to the cartilage and meniscal history of this population of patients who had undergone several repairs of the ACL, the results were satisfactory and little different from those obtained with the same primary procedure in a control group. The residual laxity study showed that the mechanical quality of the transplant was good. Histology studies published on repeat patellar tendon harvesting have been discordant.

Conclusions: Repeat harvesting of the patellar tendon for ACL repair appears to be an excellent alternative since it is thicker than the primary transplant and thus fills the bone defects better than other transplants (particularly hamstring).