RESTORATION OF THE ROTATION CENTER IN MINIMALLY-INVASIVE TOTAL HIP REPLACEMENT

Objective: Our aim was to evaluate the challenges in obtaining a successful restoration of the rotation center as well as a good positioning of the acetabular component when using the minimally-invasive posterior approach for uncemented total hip replacement. Methods: In a comparative non-random prospective study, 64 adult patients underwent elective total hip arthroplasty using the minimally-invasive posterior approach performed by one single surgeon, All patients included in this study had a superior and lateral migration of the rotation center of the hip in comparison to the normal contralateral hip. Patients were excluded from the study if they presented the following: diagnosis of femoral neck fracture, displasic hip types 2, 3 and 4 (Crowe`s classification), osteoarthritis of the contralateral hip. Of the 64 patients in the study, 39 had a radiographic pre-op acetabular size planning equal or less than 50 mm and 25 patients had a radiographic pre-op acetabular size planning equal or more than 52 mm. We considered a good result the following goals: acetabular bend between 35 and 50 degrees, acetabular size according to the pre-op estimative with full contact in the three zones of DeLee-Charnley, a lower medial and vertical positioning of the rotation center in comparison with the pre-op values and a final limb discrepancy lower than 10 mm. Results: A better restoration of the rotation center, as well as, excellent acetabular positioning was found in patients with smaller acetabular size (equal or less than 50), p=0, 04. We must draw attention to two risks when using the minimally-invasive posterior approach: a vertical acetabular position and a lateral position of the acetabular component increasing the risk of a poor contact in the zone 1 due to an insufficient reaming of the medial acetabular host bone. Conclusion: We propose standard surgical approaches in patients with larger anatomical measurements (acetabular planning size more than 50).

Does previous hip arthroscopy negatively influence the short term clinical result of total hip replacement?

INTRODUCTION: The risk that hip preserving surgery may negatively influence the performance and outcome of subsequent total hip replacement (THR) remains a concern. The aim of this study was to identify any negative impact of previous hip arthroscopy on THR. METHODS: Out of 1271 consecutive patients who underwent primary THR between 2005 and 2009, 18 had previously undergone ipsilateral hip arthroscopy. This study group (STG) was compared with two control groups (CG, same approach, identical implants; MCG, paired group matched for age, BMI and Charnley categories). Operative time, blood loss, evidence of heterotopic bone and implant loosening at follow-up were compared between the STG and the MCG. Follow-up WOMAC were compared between the three groups. RESULTS: Blood loss was not found to be significantly different between the STG and MCG. The operative time was significantly less (p < 0.001) in the STG. There was no significant difference in follow-up WOMAC between the groups. No implant related complications were noted in follow-up radiographs. Two minor complications were documented for the STG and three for the MCG. CONCLUSION: We have found no evidence that previous hip arthroscopy negatively influences the performance or short-term clinical outcome of THR.

Painful total hip replacement due to sciatic nerve entrapment in scar tissue and lipoma.

Painful total hip replacement remains a challenging problem because of the large amount of possible diagnoses. We report about a 64-year-old female patient who was misdiagnosed during 4 years as psychiatric. She suffered of excruciating left retrotrochanteric pain after the implantation of a cementless total hip replacement and revision because of recurrent hip dislocations. Walking was limited to short distances using two crutches. The work-up at this time included the usual diagnoses and remained unsuccessful. No loosening, infection or malposition of the prosthesis could be found, and she had no neurologic deficits in her operated leg. An MRI was obtained to visualize the retrotrochanteric soft tissues and showed a tight scar surrounding the sciatic nerve, which was also compressed by an adjacent lipoma. Therefore, she was reoperated on to remove the lipoma and the scar tissue around the sciatic nerve. To decrease the risk of recurrent scarring around the sciatic nerve, an adhesion barrier was applied before closure. One year after the operation, the patient has no neurologic deficit, no more pain and is able to walk unlimited distances without crutches. Scar tissue around the sciatic nerve is frequently observed during revision surgery. However, we feel that sciatic nerve entrapment by scar tissue should be a part of the differential diagnosis of painful THR. MRI may be a useful tool to achieve this diagnosis.

Influence of preoperative leg pain and radiculopathy on outcomes in mono-segmental lumbar total disc replacement: results from a nationwide registry.

PURPOSE: Currently, many pre-conditions are regarded as relative or absolute contraindications for lumbar total disc replacement (TDR). Radiculopathy is one among them. In Switzerland it is left to the surgeon's discretion when to operate if he adheres to a list of pre-defined indications. Contraindications, however, are less clearly specified. We hypothesized that, the extent of pre-operative radiculopathy results in different benefits for patients treated with mono-segmental lumbar TDR. We used patient perceived leg pain and its correlation with physician recorded radiculopathy for creating the patient groups to be compared. METHODS: The present study is based on the dataset of SWISSspine, a government mandated health technology assessment registry. Between March 2005 and April 2009, 577 patients underwent either mono- or bi-segmental lumbar TDR, which was documented in a prospective observational multicenter mode. A total of 416 cases with a mono-segmental procedure were included in the study. The data collection consisted of pre-operative and follow-up data (physician based) and clinical outcomes (NASS form, EQ-5D). A receiver operating characteristic (ROC) analysis was conducted with patients' self-indicated leg pain and the surgeon-based diagnosis "radiculopathy", as marked on the case report forms. As a result, patients were divided into two groups according to the severity of leg pain. The two groups were compared with regard to the pre-operative patient characteristics and pre- and post-operative pain on Visual Analogue Scale (VAS) and quality of life using general linear modeling. RESULTS: The optimal ROC model revealed a leg pain threshold of 40 ≤ VAS > 40 for the absence or the presence of "radiculopathy". Demographics in the resulting two groups were well comparable. Applying this threshold, the mean pre-operative leg pain level was 16.5 points in group 1 and 68.1 points in group 2 (p < 0.001). Back pain levels differed less with 63.6 points in group 1 and 72.6 in group 2 (p < 0.001). Pre-operative quality of life showed considerable differences with an 0.44 EQ-5D score in group 1 and 0.29 in group 2 (p < 0.001, possible score range -0.6 to 1). At a mean follow-up time of 8 months, group 1 showed a mean leg pain improvement of 3.6 points and group 2 of 41.1 points (p < 0.001). Back pain relief was 35.6 and 39.1 points, respectively (p = 0.27). EQ-5D score improvement was 0.27 in group 1 and 0.41 in group 2 (p = 0.11). CONCLUSIONS: Patients labeled as having radiculopathy (group 2) do mostly have pre-operative leg pain levels ≥ 40. Applying this threshold, the patients with pre-operative leg pain do also have more severe back pain and a considerably lower quality of life. Their net benefit from the lumbar TDR is higher and they do have similar post-operative back and leg pain levels as well as the quality of life as patients without pre-operative leg pain. Although randomized controlled trials are required to confirm these findings, they put leg pain and radiculopathy into perspective as absolute contraindications for TDR.

Outcome evaluation of ankle osteoarthritis treatments: plantar pressure analysis during relatively long-distance walking.

Background : This study aimed to use plantar pressure analysis in relatively long-distance walking for objective outcome evaluation of ankle osteoarthritis treatments, i.e., ankle arthrodesis and total ankle replacement.Methods : Forty-seven subjects in four groups: three patient groups and controls, participated in the study. Each subject walked twice in 50-m trials. Plantar pressure under the pathological foot was measured using pressure insoles. Six parameters: initial contact time, terminal contact time, maximum force time, peak pressure time, maximum force and peak pressure were calculated and averaged over trials in ten regions of foot. The parameters in each region were compared between patient groups and controls and their effect size was estimated. Besides, the correlations between pressure parameters and clinical scales were calculated.Findings : We observed based on temporal parameters that patients postpone the heel-off event, when high force in forefoot and high ankle moment happens. Also based on maximum force and peak pressure, the patients apply smoothened maximum forces on the affected foot. In ten regions, some parameters showed improvements after total ankle replacement, some showed alteration of foot function after ankle arthrodesis and some others showed still abnormality after both surgical treatments. These parameters showed also significant correlation with clinical scales in at least two regions of foot.Interpretation : Plantar pressure parameters in relatively long-distance trials showed to be strong tools for outcome evaluation of ankle osteoarthritis treatments. (C) 2010 Elsevier Ltd. All rights reserved.

Analysis of joint laxity after total ankle arthroplasty: cadaver study.

BACKGROUND: Clinical results of total ankle arthroplasty with early designs were disappointing. Recently-developed ankle prostheses have good mid-term results; however, limited information is available regarding effects of total ankle arthroplasty on ankle laxity. METHODS: Eight cadaveric lower extremities were tested with a custom device which enabled measurement of multi-axial forces, moments, and displacement during applied axial, shear, and rotational loading. Tests consisted of anterior-posterior and medial-lateral translation and internal-external rotation of the talus relative to the tibia during axial loads on the tibia simulating body weight (700 N) and an unloaded condition (5 N). Tests were performed in neutral, dorsiflexion, and plantarflexion. Laxity was determined for the intact ankle, and following insertion of an unconstrained total ankle implant, comparing load-displacement curve. FINDINGS: Laxity after total ankle arthroplasty did not approximate the normal ankle in most conditions tested. Displacement was significantly greater for total ankle arthroplasty in both posterior and lateral translation, and internal rotation, with 5 N axial loading, and anterior-posterior, medial-lateral translation, and internal-external rotation for 700 N axial loading. For the 700 N axial load condition, in the neutral ankle position, total anterior-posterior translation averaged 0.4 mm (SD 0.2 mm), but 6.0 mm (SD 1.5 mm) after total ankle arthroplasty (P<0.01). This study demonstrated more laxity in the replaced ankle than normal ankle for both unloaded and 700 N axially loaded conditions. INTERPRETATION: These data indicate the increased responsibility of the ligaments for ankle laxity after total ankle arthroplasty and suggest the importance of meticulous ligament reconstruction with total ankle arthroplasty operations.

Radiographic total disc replacement angle measurement accuracy using the Oxford Cobbometer: precision and bias.

Total disc replacement (TDR) clinical success has been reported to be related to the residual motion of the operated level. Thus, accurate measurement of TDR range of motion (ROM) is of utmost importance. One commonly used tool in measuring ROM is the Oxford Cobbometer. Little is known however on its accuracy (precision and bias) in measuring TDR angles. The aim of this study was to assess the ability of the Cobbometer to accurately measure radiographic TDR angles. An anatomically accurate synthetic L4-L5 motion segment was instrumented with a CHARITE artificial disc. The TDR angle and anatomical position between L4 and L5 was fixed to prohibit motion while the motion segment was radiographically imaged in various degrees of rotation and elevation, representing a sample of possible patient placement positions. An experienced observer made ten readings of the TDR angle using the Cobbometer at each different position. The Cobbometer readings were analyzed to determine measurement accuracy at each position. Furthermore, analysis of variance was used to study rotation and elevation of the motion segment as treatment factors. Cobbometer TDR angle measurements were most accurate (highest precision and lowest bias) at the centered position (95.5%), which placed the TDR directly inline with the x-ray beam source without any rotation. In contrast, the lowest accuracy (75.2%) was observed in the most rotated and off-centered view. A difference as high as 4 degrees between readings at any individual position, and as high as 6 degrees between all the positions was observed. Furthermore, the Cobbometer was unable to detect the expected trend in TDR angle projection with changing position. Although the Cobbometer has been reported to be reliable in different clinical applications, it lacks the needed accuracy to measure TDR angles and ROM. More accurate ROM measurement methods need to be developed to help surgeons and researchers assess radiological success of TDRs.

Total hip replacement with a collarless polished cemented anatomic stem: clinical and gait analysis results at ten years follow-up.

PURPOSE: The aim of this study was to determine outcomes of total hip replacement (THR) with the Lemania cemented femoral stem. METHODS: A total of 78 THR patients were followed and compared to 17 "fit", healthy, elderly and 72 "frail" elderly subjects without THR, using clinical outcome measures and a portable, in-field gait analysis device at five and ten years follow-up. RESULTS: Forty-one patients (53%), mean age 83.4 years, available at ten years follow-up, reported very good to excellent satisfaction. Mean Harris Hip and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were 81.2 and 10.5 points, respectively, with excellent radiological preservation of proximal femur bone stock. Spatial and temporal gait parameters were close to the fit group and better than the frail group. CONCLUSIONS: Lemania THR demonstrated very good, stable clinical and radiological results at ten years in an older patient group, comparable to other cemented systems for primary THR. Gait analysis confirmed good walking performance in a real-life environment.

Outcome after proximal femoral fractures during primary total hip replacement by the direct anterior approach.

BACKGROUND: The literature suggests that intraoperative fractures of the greater trochanter and the metaphysis are increased with uncemented stems and the direct anterior approach. This study aims to determine the incidence and assess the functional and radiological outcome after such fractures. METHODS: 484 consecutive total hip replacements (THR) (64 ± 12 years) were analyzed. We treated trochanteric fractures conservatively without any further denuding, and secured metaphyseal fissures with cerclages. Postoperative X-rays and at the latest follow-up were compared to assess secondary fracture displacement and stem subsidence. Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores after 1 year were analyzed. For each patient sustaining a fracture, two patients without fractures were matched in terms of age, body mass index and gender. RESULTS: 13 (2.7 %, 5 male, 68 ± 9 years) patients with intraoperative fractures of the greater trochanter (n = 8) or the metaphysis (n = 5) were analyzed. Consolidation was observed in 7/8 patients sustaining a trochanteric fracture while secondary displacement of the fragment occurred in one case. Stem subsidence was observed in 2/5 cases (5 and 7 mm). Patients who sustained a fracture showed a trend towards poorer WOMAC scores at 1 year postoperatively, compared to patients without fractures. A significantly increased joint stiffness was also observed. CONCLUSION: The intraoperative fracture risk in this series of THR through a direct anterior approach was 2.7 %. Trochanteric fractures do heal without primary fixation. Metaphyseal fractures heal well if immediately stabilized with a cerclage.

Negative emotions affect postoperative scores for evaluating functional knee recovery and quality of life after total knee replacement

This study aimed to determine whether psychological factors affect health-related quality of life (HRQL) and recovery of knee function in total knee replacement (TKR) patients. A total of 119 TKR patients (male: 38; female: 81) completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), State Trait Anxiety Inventory (STAI), Eysenck Personality Questionnaire-revised (EPQR-S), Knee Society Score (KSS), and HRQL (SF-36). At 1 and 6 months after surgery, anxiety, depression, and KSS scores in TKR patients were significantly better compared with those preoperatively (P<0.05). SF-36 scores at the sixth month after surgery were significantly improved compared with preoperative scores (P<0.001). Preoperative Physical Component Summary Scale (PCS) and Mental Component Summary Scale (MCS) scores were negatively associated with extraversion (E score) (B=-0.986 and -0.967, respectively, both P<0.05). Postoperative PCS and State Anxiety Inventory (SAI) scores were negatively associated with neuroticism (N score; B=-0.137 and -0.991, respectively, both P<0.05). Postoperative MCS, SAI, Trait Anxiety Inventory (TAI), and BAI scores were also negatively associated with the N score (B=-0.367, -0.107, -0.281, and -0.851, respectively, all P<0.05). The KSS function score at the sixth month after surgery was negatively associated with TAI and N scores (B=-0.315 and -0.532, respectively, both P<0.05), but positively associated with the E score (B=0.215, P<0.05). The postoperative KSS joint score was positively associated with postoperative PCS (B=0.356, P<0.05). In conclusion, for TKR patients, the scores used for evaluating recovery of knee function and HRQL after 6 months are inversely associated with the presence of negative emotions.

Preoperative education and its influence on perception of recovery for clients awaiting total hip and total knee replacement surgery /

The puqjose of this study was to examine the manner in which an inviting approach to a preoperative teaching and learning educational experience influenced the perception and subsequent recovery of clients who were awaiting total hip and total knee replacement surgery. An in-depth review of the internal and external factors that shape client perceptions was undertaken in this study. In addition, this study also explored whether or not the Prehab Program was preparing clients physically, socially, and psychologically for surgery. Data for this qualitative case study research were collected through preoperative interviews with 4 participants awaiting total hip replacement surgery and 1 participant awaiting total knee replacement surgery. Four postoperative interviews were conducted with the participants who had received total hip replacement surgery. The occupational therapist and physical therapist who were the coleaders of the Prehab Program at the time of this study were also interviewed. The results of this study suggest that while individuals may receive similar educational experiences, their perceptions of the manner in which they benefited from these experiences varied. This is illustrated in the research findings, which concluded that while clients benefited physically from the inviting approach used during the practical teaching session, not all clients perceived the psychological benefits of this practice session, especially clients with preexisting high levels of anxiety. In addition to increasing the understanding of the internal as well as external factors that influence the perceptions of clients, this study has also served as an opportunity for reflection on practice for the Prehab therapists and other healthcare educators.