Alastair Younger

The outcome of two-stage arthroplasty using a custom-made interval spacer to treat the infected hip

Sixty-one patients undergoing a two-stage revision of an infected hip using a prosthesis of antibiotic-loaded acrylic cement were followed for an average of 43 months. Twelve patients were excluded (3 died, 6 had no proven infection, and 2 no second stage). Only 1 patient was lost to follow-up evaluation from those included, for a retrieval rate of 98% for those still living. Of the remaining 48 patients, 3 had further sepsis: Two became reinfected with different organisms and 1 with the same organism, for an infection eradication rate of 94%. The other 45 had no clinical, laboratory, or radiographic evidence of infection. Thirty-seven patients (80%) had a Harris hip score greater than 80 or an improvement of at least 30 points.

Comparison of Health-Related Quality of Life Between Patients with End-Stage Ankle and Hip Arthrosis

BACKGROUND End-stage ankle arthrosis is one of the leading causes of chronic disability in North America. Information on this condition is limited. The amount of pain and the reduction in health-related quality of life and function have not been quantified with use of universal outcome measures. The purpose of the present study was to compare the extent of pain, loss of function, and health-related quality of life in two cohorts of patients waiting for the surgical treatment of end-stage ankle or hip arthrosis. METHODS One hundred and thirty patients with end-stage ankle arthrosis who were awaiting total ankle arthroplasty or ankle arthrodesis were recruited through a Canadian Orthopaedic Foot and Ankle Society multicenter study. All patients prospectively completed the Short Form-36 (SF-36) generic outcome instrument. This cohort was compared with a similar cohort of 130 patients with end-stage hip arthrosis, randomly selected from an existing prospective joint replacement database, who had completed an SF-36 questionnaire prospectively from 2000 to 2005. RESULTS In both groups, the scores for all SF-36 subscales were approximately two standard deviations below normal population scores. Patients with ankle arthrosis had significantly worse mental component summary scores (p < 0.05), role-physical scores (p < 0.05), and general health scores (p < 0.05). Patients with hip arthrosis reported significantly lower physical function scores (p < 0.05), although the SF-36 physical component summary score was not significantly different between the two groups. The SF-36 physical component summary, bodily pain, vitality, role-emotional, social functioning, and mental health subscale scores were equally affected in both cohorts. CONCLUSIONS The mental and physical disability associated with end-stage ankle arthrosis is at least as severe as that associated with end-stage hip arthrosis.

Radiographic Assessment of Adult Flatfoot

Background: The accurate measurement of flatfoot on standing radiographs allows correct diagnosis of the condition and evaluation of reconstructive procedures. Method: The standing radiographic measurements of patients with symptomatic, adult flatfoot were compared to controls using blinded observers.Results: On the lateral radiograph, the talar-to-first metatarsal angle, the calcaneal pitch angle, and the medial cuneiform-fifth metatarsal height differed significantly between the patient group and the controls. The difference in the talar-to-first metatarsal angles on lateral radiographs was the most statistically significant (patient group 21.1 ±10.8 degrees and control 7.1 ± 10.7 degrees, p < 0.0001) with good correlation between readings (intraobserver 0.75, interobserver 0.83). On the anteroposterior (AP) radiograph, the talar head uncoverage distance was the most significantly different measurement between these groups. Conclusions: These findings support the hypothesis that the talar-first metatarsal angle is an accurate radiographic identifier of patients with symptomatic, adult flatfoot.

Responsiveness and Validity of the SF-36, Ankle Osteoarthritis Scale, AOFAS Ankle Hindfoot Score, and Foot Function Index in End Stage Ankle Arthritis

Background: We examined four commonly used scores, the SF-36, the Ankle Osteoarthritis Scale (AOS), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score, and the Foot Function Index (FFI) to determine their responsiveness and validity. Methods: Patients with end stage ankle arthritis were recruited into a prospective multicenter cohort study and baseline and one year outcome scores were compared. The Standardized Response Mean and Effect Size for the AOS, AOFAS, and FFI were calculated and the three region- or disease-specific scores were compared with the SF-36 to determine their criterion validity. Results: All four scores showed acceptable responsiveness, and when using the validated SF-36 as the standard the three region or disease specific scores all showed similar criterion validity. Conclusion: All four scores are responsive and can be considered for use in this population. The objective component of the AOFAS Ankle Hindfoot Score may make it harder to perform than the other three scores which have subjective components only, and as yet its objective component has not been shown to demonstrate reliability. We recommend use of a purely subjective score such as the Ankle Osteoarthritis Scale or Foot Function Index as the region- or disease-specific score of choice in this population. As the SF-36 shows acceptable responsiveness, using it alone could also be considered. Level of Evidence: II, Prospective Comparative Study

Treatment of Infection Associated with Segmental Bone Loss in the Proximal Part of the Femur in Two Stages with Use of an Antibiotic-Loaded Interval Prosthesis*

Treatment of an infection at the site of a total hip replacement associated with extensive loss of the proximal part of the femur is a challenging problem. In the present preliminary report, we describe the results after use of a prosthesis of antibiotic-loaded acrylic cement (PROSTALAC) in thirty such hips. The purpose of the prosthesis, which acts as an internal splint, is to maintain the length of the femur as well as the range of motion of the joint and the mobility of the patient between stages. A local level of antibiotics is maintained by the antibiotic-coated surface. A PROSTALAC with a cement-on-cement articulation was used in the first fifteen hips (Group I) in the study, and a custom metal-on-polyethylene articulating PROSTALAC was inserted in the subsequent fifteen hips (Group II). One patient who had a recurrent infection was managed with a second two-stage exchange and was included in both groups. Between stages, the average limb-length discrepancy was twenty-five millimeters despite a loss of more than 25 per cent of the femur in nineteen limbs. Sixteen patients were discharged home and seven, to a community hospital between stages. Six patients in Group I and only one in Group II were hospitalized for the entire course of treatment. The total duration of hospitalization for both stages averaged thirty-eight days. Twenty-eight patients were mobile even though they did not bear weight on the involved limb between stages: three patients used a cane, fifteen used crutches, and ten used a walker. Twenty-six patients reported no, slight, or moderate pain in the thigh, groin, or buttock between stages. The average Harris hip score before the first stage of the operation was 23 points (range, 0 to 63 points), which improved to 74 points (range, 40 to 91 points) at an average of forty-seven months (range, twenty-four to 114 months) postoperatively. Two patients died of unrelated causes before two years (the minimum follow-up period) had elapsed and were excluded from the final analysis; they had no evidence of recurrent infection. Of the remaining twenty-eight hips, twenty-seven (96 per cent) had no evidence of infection at the most recent follow-up examination.

Intermediate-Term Results of Total Ankle Replacement and Ankle Arthrodesis

BACKGROUND Surgical treatments for end-stage ankle arthritis include total ankle replacement and ankle arthrodesis. Although arthrodesis is a reliable procedure, ankle replacement is often preferred by patients. This prospective study evaluated intermediate-term outcomes of ankle replacement and arthrodesis in a large cohort at multiple centers, with variability in ankle arthritis type, prosthesis type, surgeon, and surgical technique. We hypothesized that patient-reported clinical outcomes would be similar for both procedures. METHODS Patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database were treated with total ankle replacement (involving Agility, STAR, Mobility, or HINTEGRA prostheses) or ankle arthrodesis by six subspecialty-trained orthopaedic surgeons at four centers between 2001 and 2007. Data collection included demographics, comorbidities, and the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) scores. The preoperative and latest follow-up scores for patients with at least four years of follow-up were analyzed. Sensitivity analyses excluded ankles that had undergone revision. A linear mixed-effects regression model compared scores between the groups, adjusting for age, sex, side, smoking status, body mass index, inflammatory arthritis diagnosis, baseline score, and surgeon. RESULTS Of the 388 ankles (281 in the ankle replacement group and 107 in the arthrodesis group), 321 (83%; 232 ankle replacements and eighty-nine arthrodeses) were reviewed at a mean follow-up of 5.5 ± 1.2 years. Patients treated with arthrodesis were younger, more likely to be diabetic, less likely to have inflammatory arthritis, and more likely to be smokers. Seven (7%) of the arthrodeses and forty-eight (17%) of the ankle replacements underwent revision. The major complications rate was 7% for arthrodesis and 19% for ankle replacement. The AOS total, pain, and disability scores and SF-36 physical component summary score improved between the preoperative and final follow-up time points in both groups. The mean AOS total score improved from 53.4 points preoperatively to 33.6 points at the time of follow-up in the arthrodesis group and from 51.9 to 26.4 points in the ankle replacement group. Differences in AOS and SF-36 scores between the arthrodesis and ankle replacement groups at follow-up were minimal after adjustment for baseline characteristics and surgeon. CONCLUSIONS Intermediate-term clinical outcomes of total ankle replacement and ankle arthrodesis were comparable in a diverse cohort in which treatment was tailored to patient presentation; rates of reoperation and major complications were higher after ankle replacement.

Impact of Complications in Total Ankle Replacement and Ankle Arthrodesis Analyzed with a Validated Outcome Measurement

BACKGROUND Major modifications in the design and techniques of total ankle replacement have challenged the perception that ankle arthrodesis is the treatment of choice for end-stage ankle arthritis. High complication and revision rates have been reported after both procedures. METHODS We performed radiographic evaluations at a mean of thirty-nine months following 114 total ankle replacements done with use of commonly used implants and at a mean of thirty-seven months following forty-seven ankle arthrodeses. The mean age was sixty-four years for the patients (fifty-one female and sixty-three male) who underwent total ankle replacement and fifty-nine years in the patients (fifteen female and thirty-two male) who underwent ankle arthrodesis. The impact of complications was analyzed with use of the Ankle Osteoarthritis Scale (AOS), a validated outcome instrument. RESULTS Both groups had significant improvement in the mean AOS score (p < 0.001). There was no significant difference in the mean improvement between the two groups (p = 0.96). The complication rate was 54% following total ankle replacement and 26% following ankle arthrodesis, which was a significant difference (p = 0.003). The impact of major complications on the AOS outcome score was significant in both the total ankle replacement group (p = 0.031) and the ankle arthrodesis group (p = 0.02). CONCLUSIONS At the time of follow-up, at a minimum of two years postoperatively, the outcomes of total ankle replacement and ankle arthrodesis, with regard to pain relief and function, were comparable. While the rate of complications was significantly higher following total ankle replacement, the impact of complications on outcome was clinically relevant in both groups.

Adult Cavovarus Foot

&NA; Cavovarus foot deformity, which often results from an imbalance of muscle forces, is commonly caused by hereditary motor sensory neuropathies. Other causes are cerebral palsy, cerebral injury (stroke), anterior horn cell disease (spinal root injury), talar neck injury, and residual clubfoot. In cavovarus foot deformity, the relatively strong peroneus longus and tibialis posterior muscles cause a hindfoot varus and forefoot valgus (pronated) position. Hindfoot varus causes overload of the lateral border of the foot, resulting in ankle instability, peroneal tendinitis, and stress fracture. Degenerative arthritic changes can develop in overloaded joints. Gait examination allows appropriate planning of tendon transfers to correct stance and swing‐phase deficits. Inspection of the forefoot and hindfoot positions determines the need for softtissue release and osteotomy. The Coleman block test is invaluable for assessing the cause of hindfoot varus. Prolonged use of orthoses or supportive footwear can result in muscle imbalance, causing increasing deformity and irreversible damage to tendons and joints. Rebalancing tendons is an early priority to prevent unsalvageable deterioration of the foot. Muscle imbalance can be corrected by tendon transfer, corrective osteotomy, and fusion. Fixed bony deformity can be addressed by fusion and osteotomy.

Surgical Exposures in Revision Total Knee Arthroplasty

&NA; A well‐planned operative approach to revision total knee arthroplasty is crucial to a successful outcome. Wide exposure must be achieved to allow component removal, soft‐tissue balancing, management of bone loss, and reimplantation without damaging important structures. These structures include skin, the extensor mechanism, the collateral ligaments, the remaining bone stock, and neurovascular structures. Skin necrosis can be avoided by selecting the appropriate incision and dissecting deep to the fascia. Extensile exposure by dissection of scar, quadriceps snip or turndown, tibial tubercle osteotomy, or medial epicondylar osteotomy should be performed early to prevent patellar tendon disruption. In certain cases, the distal femur can be exposed circumferentially by using a quadriceps myocutaneous flap or femoral peel. Special care should be taken with the infected or ankylosed knee.

Intra- and Inter-observer Reliability of the Distal Metatarsal Articular Angle in Adult Hallux Valgus:

There is some uncertainty as to whether the distal metatarsal articular angle (DMAA) is a real entity or just radiographic artifact and whether it can be reliably measured. If it is intrinsic to the bone, it should not change with bone position. If it is clinically useful, it should be reproducible. Pre-operative and post-operative radiographs of 32 patients undergoing a proximal bony procedure of the first ray were evaluated independently by three foot and ankle specialists in order to determine the intra and inter-observer reliability of the distal metatarsal articular angle (DMAA). In addition, the hallux valgus angle (HVA), intermetatarsal angle (IMA) and joint congruency/subluxation were determined. We used ANOVA (Scheffes F-test) to determine reliability of the angular measurements; a p value of less than 0.05 indicates poor reliability and a p value of greater than 0.05 indicates reliability. Intra-observer reliability was good for all angular measurements (HVA, IMA, DMAA pre-op, and DMAA postop) with p values ranging from 0.33 to 0.95. Inter-observer reliability of the HVA and IMA was good (p = 0.63 and p = 0.32). Inter-observer reliability of the pre-op DMAA approached statistically poor reliability (p = 0.09) and the post-op DMAA reliability was poor (p = 0.002). The DMAA reduced after the proximal procedure as measured by all observers, and averaged a reduction of 3.9°. Weighted kappa analysis also revealed that there was poor agreement in the determination of congruency and subluxation (Kappa statistic ranged from 0.07 to 0.19). This study suggests that there may be limited value in the DMAA as a clinical measure as it varies with examiner and with the hallux valgus angle.