Function and osteoarthritis progression after arthroscopic treatment of femoro-acetabular impingement: a prospective study after a mean follow-up of 4.6 (4.2-5.5) years.

BACKGROUND: Outcomes after arthroscopic femoro-acetabular impingement (FAI) surgery are promising in the short-term but have rarely been evaluated in the mid-term (e.g., about 5 years). Here, our objectives were to obtain mid-term data on functional and radiographic outcomes, to identify prognostic factors, and to determine the mid-term rate of arthroplasty revision with the associated risk factors. HYPOTHESIS: We hypothesized that the results of arthroscopic FAI surgery were sustained over time. MATERIALS AND METHODS: We conducted a prospective multi-surgeon study of 53 Tönnis grade 0 or 1 hips treated arthroscopically for symptomatic FAI (23 cam, 10 pincer, and 20 mixed deformities). We obtained short-term (10 months) and mid-term (4.6 years) data on the functional outcome (WOMAC and satisfaction scores), proportion of patients without revision arthroplasty, and development of osteoarthritis (graded using the Tönnis classification). RESULTS: In the patients without revision arthroplasty, the WOMAC score improved significantly (P<0.01) from baseline (61.4 ± 15.6) to 10 months (84.2 ± 15.6) and last follow-up (85.2 ± 15.5) but remained unchanged between the two postoperative time points, confirming the stability of the results. The proportion of satisfied patients was 79% after 10 months and 68% (36/53) at last follow-up (NS). Osteoarthritis developed in 13/35 (37%) hips for which radiographs were obtained at last follow-up. At last follow-up, 46/53 hips (87%; 95%CI, 78-96) did not required revision surgery; arthroplasty was required in the 7 remaining hips. The main prognostic factor was the preoperative osteoarthritis Tönnis grade: at last follow-up, compared to Tönnis grade 0 hips, Tönnis grade 1 hips had lower WOMAC scores (77 vs. 88), lower satisfaction rates (50% versus 77%), a higher rate of osteoarthritis progression (57% versus 24%), and a higher rate of arthroplasty (33.3% versus 2.9%). DISCUSSION: Our results are consistent with published data. The outcomes of arthroscopic FAI surgery are sustained over time and the preoperative osteoarthritis status is the main predictor of mid-term outcomes. LEVEL OF EVIDENCE: IV, prospective cohort study.

De-escalation exchange of loosened locked revision stems to a primary stem design: complications, stem fixation and bone reconstruction in 15 cases.

INTRODUCTION: Femoral stem revision with a locked stem after total hip arthroplasties treats severe bone defects by favoring spontaneous bone reconstruction. Initially, once reconstruction was obtained, the temporary implant was to be replaced by a standard primary component. The use of locked stems has increased, but repeat revision with a short stem which is also called "de-escalation" has not been extensively studied. HYPOTHESIS: Repeat revision of a locked stem with a short stem is not associated with any specific morbidity and does not affect the quality of reconstruction obtained, or fixation of the subsequent standard length primary design stem. PATIENTS AND METHODS: Fifteen patients whose locked femoral stem was exchanged due to thigh pain and/or radiographic images showing failed osteointegration were analyzed. These 15 patients were all followed-up and evaluated by the Postel Merle d'Aubigné score. Progression of bone defects was evaluated using the Hofmann cortical index. RESULTS: There were no difficulties extracting the locked stem and a standard length primary stem was inserted with no associated procedures or bone complications in any of the cases. At a mean follow-up of 55 months (36-84months), thigh pain had disappeared and the Postel Merle d'Aubigné score had increased from 12.6±2.9 (7-16) to 16.5±0.9 (15-18) (P=0.0001). The use of a locked femoral stem resulted in bone reconstruction in all cases, the Hofmann index increased from 30.5%±17.9% (12-71%) before insertion of the locked stem to 43.6%±25.6% (19-90%) at exchange (P<0.05). Bone reconstruction was durable after the exchange with a stable Hofmann index 43.7%±26.2% (17-92%) at the final follow-up (P=0.9). No recurrent loosening occurred. DISCUSSION: Revision of a loosened locked femoral stem with a standard design primary stem does not result in any specific increased morbidity, or modify bone reconstruction obtained with the locked stem and results in stable fixation of a new standard length stem. LEVEL OF EVIDENCE: IV: retrospective or historical series.

Femoral head to neck offset after hip resurfacing is critical for range of motion.

BACKGROUND: Range of motion after hip arthroplasty may be limited by soft tissues around the hip, extra-articular contact and femoral stem-neck contact with the acetabular articular surface. Femoral head-neck diameter ratio is recognized as a major factor influencing hip range of motion. In hip resurfacing, range of motion is constrained by "cup component to femoral neck" contact. To avoid cup-to-bone contact or to increase the degree of flexion at which it occurs, anterior translation of the femoral component relative to the central femoral neck axis may improve anterior head-neck offset and hip flexion. We questioned whether low or high anterior femoral head to neck offset, cup inclination, stem anteversion, and component size influenced postoperative range of motion and hip flexion in patients who had undergone hip resurfacing. METHODS: We prospectively followed 66 patients (68 hips) who underwent hip resurfacing at a mean age at operation of 46.4 years (range, 19-60 years). Mean follow-up was 37.5 months (range, 33-41 months). No patient was lost to follow-up. All patients were evaluated clinically and range of motion was precised. Radiological measurement evaluated the anterior femoral head-neck offset. FINDINGS: Mean anterior neck-head offset was 7.5mm (range, 5-12 mm). We found significant linear regression correlation between anterior offset and flexion (R=0.66) and between anterior offset and global range of motion (R=0.51). One millimeter of anterior offset increased hip range of motion by 5° in flexion. No significant correlations were found between global range of motion or flexion arc of motion and component size, stem anteversion, cup inclination, gender ratio, preoperative arc of flexion or global range of motion. INTERPRETATION: Restoring or improving deficient anterior femoral head-neck offset appears important for restoring postoperative range of motion and specifically hip flexion.

Component impingement in total hip arthroplasty: frequency and risk factors. A continuous retrieval analysis series of 416 cup.

INTRODUCTION: Impingement is a factor of failure in total hip replacement (THR), causing instability and early wear. Its true frequency is not known; cup-retrieval series reported rates varying from 27 to 84%. HYPOTHESIS: The hypothesis was that a large continuous series of THR cup removals would help determine the frequency of component impingement. OBJECTIVES: The hypothesis was tested on a continuous retrospective series of cups removed in a single center, with a secondary objective of identifying risk factors. MATERIAL AND METHODS: [corrected] Macroscopic examination looked for component impingement signs in 416 cups retrieved by a single operator between 1989 and 2004. Risk factors were investigated by uni- and multivariate analyses in the 311 cases for which there were complete demographic data. In these 311 cases, removal was for aseptic loosening (131 cases), infection (43 cases), instability (56 cases), osteolysis (28 cases) or unexplained pain (48 cases); impingement was explicitly implicated in only five cases (1.6%), always with hard-on-hard bearing components. RESULTS: Impingement was found in 214 of the 416 cups (51.4%) and was severe (notch>1mm) in 130 (31.3%). In the subpopulation of 311 cups, impingement was found in 184 cases (59.2%) and was severe in 109 (35%). Neither duration of implant use nor cup diameter or frontal orientation emerged as risk factors. On univariate analysis, impingement was more frequently associated with revision for instability, young patient age at THR, global hip range of motion >200° or use of an extended femoral head flange (or of an elevated antidislocation rim liner), and was more severe in case of head/neck ratio<2. On multivariate analysis, only use of an extended head flange (RR 3.2) and revision for instability (RR 4.2) remained as independent risk factors for impingement. DISCUSSION: Component impingement is frequently observed in cups after removal, but is rarely found as a direct indication for revision, except in case of hard-on-hard friction couples (polyethylene being the most impingement-tolerant material). Systematic use of extended head flanges and elevated antidislocation rims is not to be recommended, especially in case of excessive ROM. A good head/neck ratio should be sought, notably by increasing the head diameter in less impingement-tolerant hard-on-hard friction couples. Although not identified as a risk factor in the present study, implant orientation should be checked; computer-assisted surgery can be useful in this regard, for adaptation to the patient's individual range-of-motion cone.

Shelf arthroplasties long-term outcome: influence of labral tears. A prospective study at a minimal 16 years' follows up.

INTRODUCTION: Osteoarthritis lesions extent and dysplasia severity (negative vertical center edge [CE] angle) are recognized as unfavorable criteria for the survival of shelf arthroplasties performed for correcting hip dysplasia. Labral tears have recently been described on dysplastic hips, indicating beginning osteoarthritis and worsening the risk of instability. HYPOTHESIS: The labral tears identified in the course of shelf arthroplasty procedures for correction of hip dysplasia carry a predictive value for the survival of this operation. OBJECTIVES: Evaluate this hypothesis at the intermediate term in a long-term prospective observational study. PATIENT AND METHODS: Eighteen adult patients (18 dysplastic hips) having undergone shelf arthroplasty were included consecutively in a continuous prospective study. At the time the shelf arthroplasty was performed, a hip arthroscopic exam was carried out to search for and resect a labral tear if necessary. Fifteen patients were reviewed with a minimum follow-up of 16 years. Two patients died and one patient was lost to follow-up. RESULTS: During arthroscopic exploration, 10 hips presented labral tears (55.6%). At a mean follow-up of 16.3 years (range, 16-18 years), eight hips underwent hip arthroplasty. Of these hips, only one did not present a labral tear. The seven other hips had a tear of the labrum (p<0.001). The overall survival rate was 41.3%; it was 83.3% for hips with no labral tear and 15.2% for hips with a lesion of the labrum (p=0.048). DISCUSSION AND CONCLUSION: Labral tears had a negative impact on the outcome of shelf arthroplasty for hip dysplasia. This lesion therefore warrants being sought using appropriate exploration techniques (MRI or CT-arthrography) before shelf arthroplasty surgery. The existence of a preoperative labral tear does not seem to cast doubt on shelf arthroplasty itself. However, it should be identified so as to set objectives and expectations: long-term survival is significantly lower in the presence of a labral tear. It seems preferable to repair this type of lesion with arthroscopic guidance during shelf arthroplasty to prevent a potential source of residual pain, keeping in mind that secondary resection will be more difficult after covering the lesion. LEVEL OF EVIDENCE: Level 3 prospective observational prognostic study.

The Durom large diameter head acetabular component: early results with a large-diameter metal-on-metal bearing.

Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear. Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery. Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50 degrees (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2). The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years.

Metal ions levels measurments for early total hip replacement malfunction diagnosis with "plasma-sprayed ceramic" bearings couple.

Diagnosis of total hip arthroplasty malfunction is usually based on clinical and radiographic findings, while metal ion blood levels monitoring is generally recommended for metal-on-metal bearings hip replacements. However, these measurements may be very useful in detecting anomalies in other bearing surfaces such as plasma sprayed ceramic bearings. We report on the case of a patient with a painful cementless ceramic-on-ceramic total hip prosthesis (Plasmaceram) for which metal ions blood levels suggested revision surgery in the absence of any demonstrable radiographic anomaly. The high Cobalt and moderate Chromium ion levels in blood suggested a mechanical dysfunction of the bearing couple which revealed to be a severe cam effect requiring revision surgery of both components. Measurement of metal ion blood levels may play a substantial role in the assessment of a total hip prosthesis mechanism when using another bearing surface than metal-on-metal for which this measurement is usually recommended.