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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_13 | Pages 2 - 2
7 Aug 2023
Warder H Hall-Thompson B Sanders T Wright N Alford S Johnson D
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Abstract

The Montgomery ruling advocates patients be informed of ‘material risks’ of a procedure. With no guidelines for patients wishing to return to high activity levels after knee arthroplasty, we explore patient and surgeon perceptions in climbers.

Ethical approval was granted by the University of Central Lancashire. Anonymous questionnaires were sent via email and social media to consultant knee arthroplasty surgeons and to climbers/mountaineers across the UK. Consultants were asked about advice given for patients who participate in climbing. Climbers were asked about their experiences of knee arthroplasty and return to activity.

Of 33 knee arthroplasty surgeons, 11(33%) were firmly against any return to climbing, 10(30%) counselled against it, and 12(36%) were open to return to previous activity. Of 11(33%) surgeons who do not gather information about levels of climbing, 8 would not provide specific advice regarding risks of returning to sport. Of 28 climbers, only 5(18%) were informed to cease completely, with 11(39%) cautioned against and 12(43%) permitted to return. There was no correlation between the advice received and climbing ability post-operatively, (kappa=0.143,p=0.058), with a substantial agreement between ability 1-year post-operatively and currently, (kappa=0.689,p<0.001).

There is a discrepancy between the advice given and received by climbers/mountaineers prior to knee arthroplasty, with ability post-operatively having no relationship to advice given. Climbing is possible at high level with no reported complications following knee arthroplasty. The 1-year time point is predictive of longer-term outcome. This information should help surgeons better inform their patients preoperatively.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_11 | Pages 35 - 35
7 Jun 2023
Warder H Sanders T Wright N Hall-Thompson B Alford S Johnson D
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Climbers and mountaineers will present to arthroplasty surgeons in need of hip replacement surgeries. There is a lack of guidance for both parties with a paucity in the literature. Climbing is often considered a high-risk activity to perform with a total hip replacement, due to the positions the hip is weighted in, and the potential austere environment in which an injury may occur.

The aim was to assess levels of climbing and mountaineering possible following hip arthroplasty, and any factors affecting these levels.

Ethical approval was obtained from the University of Central Lancashire. An anonymous online questionnaire was disseminated via email, social media and word-of-mouth to include all climbers, hill-walkers or mountaineers across the UK. This was used to collect climbing and mountaineering ability at various timepoints, along with scores such as the Oxford Hip Score and UCLA Score. The Kappa statistic was used to assess for correlations.

Of the responders, 28 had undergone right hip arthroplasty surgery, with 11 having left hips and 22 receiving bilateral hips. A total of 67 of the replaced hips were total hip replacements, with 16 having undergone hip resurfacing. There is a fair agreement in level of climbing ability 3 months pre- and 3 months post-operatively (kappa=0.287, p<0.001), and a substantial agreement between 1 year post-operatively and currently for both climbing (kappa=0.730, p<0.001) and mountaineering (kappa=0.684, p<0.001). Impressively, 17 participants are climbing at more than E1 trad or 6c sport at one or more time points post operatively, which is regarded as an advanced level within the climbing community. Out of those 17 participants, 8 were climbing at this level within 3 months post-operatively.

The level of climbing possible following hip arthroplasty surgery is above what is expected and perhaps desired by the operating surgeon. It is essential to take the individual patient into account when planning an operative intervention such as arthroplasty. The one year post-operative time point is highly predictive of longer term outcomes for both climbing and mountaineering.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_8 | Pages 11 - 11
1 Aug 2020
Selley R Butler B Hartwell M Johnson D Terry M Tjong V
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Orthopaedic surgeons frequently use opioids for peri-operative pain management and there is considerable variability in the amount prescribed between surgeons. As such, the appropriate number of opioids to prescribe for specific procedures is often unknown. Leftover prescription opioids are at risk for diversion to family and friends for nonmedical use. The aim of this study was to determine the optimal amount of narcotics to prescribe postoperatively for patients undergoing hip arthroscopy.

23 consecutive patients were enrolled. All patients were prescribed 60 tablets of hydrocodone/acetaminophen 10/325 postoperatively as part of a multimodal pain management strategy. Patients were called at 14 and 21 days post-operatively to tabulate the number of pills used and knowledge of how to properly dispose of pills.

The median number of narcotic pain pills required was 6 (IQR: 3,15). Over half of patients (56.5%) required ≤10 narcotic pain pills postoperatively. A large number of narcotic tablets (1071/1380, 77.6%) were unused and a small percentage of patients (8/23, 34.8%) were aware of proper disposal techniques. Knowledge of how to properly dispose of unused narcotics was protective against a prolonged duration of narcotic use postoperatively (Parameter estimate −5.7, 95% CI: −11.3, −0.1, p = 0.045).

Reducing the number of prescribed narcotic tablets to 25 would meet the post-operative pain demands of over 85% of hip arthroscopy patients. More judicious post-operative prescribing patterns and patient education regarding disposal may help minimize physician contribution to opioid misuse, overuse and diversion.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_7 | Pages 21 - 21
1 Jul 2020
Hartwell M Nelson P Johnson D Nicolay R Christian R Selley R Tjong V Terry M
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Recent studies have described safe outcomes for short-stays in the hospital after total shoulder arthroplasty. The purpose of this study is to identify pre-operative and operative risk factors for hospital admissions exceeding 24 hours.

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried from 2006 to 2016 for the current procedural terminology (CPT) billing code related to total shoulder arthroplasty. Patients were then grouped as either having a length of stay (LOS) equal to or less than 24 hours or greater than 24 hours. Patients admitted to the hospital prior to the day of surgery were excluded. Patient demographics, co-morbidities, and operative time were then analyzed as risk factors for a hospital stay exceeding 24 hours. Pre-operative co-morbidities included body mass index (BMI), diabetes, smoking, chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), hypertension, dialysis, chronic steroid or immunosuppressant use, bleeding disorders, and American Society of Anesthesiologists (ASA) Classification. Univariate and multivariate analyses were then performed to identify risk factors associated with 30-day readmission.

14,339 patients met inclusion criteria and 6,507 (45.3%) had a hospital LOS less than or equal to 24 hours. The mean length of hospitalization was 1.95 ± 1.88 days, the average age was 69 ± 9.7 years old, and 56.9% of the patients were female. Following a risk adjusted multivariate analysis, increasing age (odds ratio [OR], 1.03, 95% confidence interval [CI], 1.02–1.03), ASA classification (OR, 1.50, 95% CI, 1.41–1.60), diabetes (OR, 1.69, 95% CI, 1.43–1.99), COPD (OR, 1.35, 95% CI, 1.16–1.57), CHF (OR, 2.67, 95% CI, 1.34–5.33), dialysis (OR, 2.47, 95% CI, 1.28, 4.77), history of a bleeding disorder (OR, 1.50, 95% CI, 1.20–1.88), or increasing operative time (OR, 1.01, 95% CI, 1.01–1.01) were identified as independent risk factors for hospital lengths of stay exceeding 24 hours. Male gender was identified as a protective factor for prolonged hospitalization (OR, 0.50, 95% CI, 0.46–0.53).

This study identifies patient demographics, co-morbidities, and operative-relative risk factors that are associated with increased risk for a prolonged hospitalization following total shoulder arthroplasty. Female gender, increasing age, ASA classification, operative time, or a history of diabetes, COPD, CHF, or history of a bleeding disorder are risk factors hospitalizations exceeding 24 hours.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_7 | Pages 72 - 72
1 Jul 2020
Nicolay R Selley R Johnson D Terry M Tjong V
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Malnutrition is an important consideration during the perioperative period and albumin is the most common laboratory surrogate for nutritional status. The purpose of this study is to identify if preoperative serum albumin measurements are predictive of infection following arthroscopic procedures.

Patients undergoing knee, shoulder or hip arthroscopy between 2006–2016 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients with an arthroscopic current procedural terminology code and a preoperative serum albumin measurement were included. Patients with a history of prior infection, including a non-clean wound class, pre-existing wound infection or systemic sepsis were excluded. Independent t-tests where used to compare albumin values in patients with and without the occurrence of a postoperative infection. Pre-operative albumin levels were subsequently evaluated as predictors of infection with logistic regression models.

There were 31,906 patients who met the inclusion criteria. The average age was 55.7 years (standard deviation (SD) 14.62) and average BMI was 31.7 (SD 7.21). The most prevalent comorbidities were hypertension (49.2%), diabetes (18.4%) and smoking history (16.9%). The average preoperative albumin was 4.18 (SD 0.42). There were 45 cases of superficial infection (0.14%), 10 cases of wound dehiscence (0.03%), 17 cases of deep infection (0.05%), 27 cases of septic arthritis or other organ space infection (0.08%) and 95 cases of any infection (0.30%). The preoperative albumin levels for patients who developed septic arthritis (mean difference (MD) 0.20, 95% CI, 0.038, 0.35, P = 0.015) or any infection (MD 0.14, 95% CI 0.05, 0.22, P = 0.002) were significantly lower than the normal population. Additionally, disseminated cancer, Hispanic race, inpatient status and smoking history were significant independent risk factors for infection, while female sex and increasing albumin were protective towards developing any infection. Rates of all infections were found to increase exponentially with decreasing albumin. The relative risk of infection with an albumin of 2 was 3.46 (95% CI, 2.74–4.38) when compared to a normal albumin of 4. For each albumin increase of 0.69, the odds of developing any infection decreases by a factor of 0.52.

This study suggests that preoperative serum albumin is an independent predictor of septic arthritis and all infection following elective arthroscopic procedures. Although the effect of albumin on infection is modest, malnutrition may represent a modifiable risk factor with regard to preventing infection following arthroscopy.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_11 | Pages 16 - 16
1 Jun 2017
Esland J Johnson D Buddhdev P Norman-Taylor F
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Purpose

The aim of this study was to identify if perioperative outcomes were different in patients with cerebral palsy undergoing unilateral or bilateral hip reconstruction.

Method

All consecutive hip reconstructions for cerebral palsy performed by the senior author (FNT) within a tertiary-referral centre were identified between January 2012 and July 2016. Patients were stratified by age, gender, GMFCS and side of procedure. Length of surgery, pre- and post- operative haemoglobin, length of stay and immediate post-operative complications were measured.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 22 - 22
1 May 2016
Gao B Angibaud L Johnson D
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Introduction

Patellofemoral joint is an important aspect of the tri-compartmental knee joint complex. Total knee arthroplasty (TKA) replaces the articulating surfaces of distal femur and proximal tibia, and often times the patella as well. Understanding the size relationship between the femur and patella bones can provide valuable information for new prosthesis design and biomechanical analysis. However, taking anthropometric measurements on a large population of patients or even cadaveric specimens could be a challenge. As a result, there are currently little quantitative data existing in the literature regarding the size relationship between TKA patient's femur and patella. This study attempted to attack this question using a novel statistical approach and a large TKA patient database.

Methods

A multi-site clinical database operated by Exactech was used in this study. The database contains patient information of Optetrak TKA implant recipients from over 30 physicians in US, UK, and Colombia since 1995. Nine femoral implant sizes (0, 1, 2, 2.5, 3, 3.5, 4, 5 and 6) and six patellar implant sizes (26, 29, 32, 35, 38, 41 mm) were seen in these patients. Due to the low usage, femoral sizes 0 and 6 were excluded from this analysis. Taking primary TKA only, a total of 2,698 cases were included in this study. The size relationship between femoral implant and patellar implant was analyzed in this patient population. Gender effect was also examined.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_10 | Pages 7 - 7
1 May 2016
Roche C Simovitch R Flurin P Wright T Johnson D Najmabadi Y Zuckerman J
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Introduction

A better understanding of the rate of improvement associated with aTSA and rTSA is critical to establish accurate patient expectations for treatment to reduce pain and restore function; more realistic patient expectations pre-operatively may lead to greater patient satisfaction post-operatively. To this end, this study quantifies the rate of improvement in outcomes of aTSA and rTSA using 5 different scoring metrics for 1641 patients with one platform shoulder arthroplasty system.

Methods

1641 patients (mean age: 69.3yrs) were treated by 14 orthopaedic surgeons using one platform shoulder system (Exactech, Inc). 729 patients received aTSA (65.3yrs; 384F/345M) for treatment of degenerative arthritis and 912 patients received rTSA (72.5yrs; 593F/319M) for treatment of CTA/RCT/OA. Each patient was scored pre-operatively and at various follow-up intervals (3 months, 6months, annually, etc) using the SST, UCLA, ASES, Constant, and SPADI metrics; active abduction, active forward flexion, and active/passive external rotation were also measured. 4439 total follow-up reports were analyzed (1851 and 2588 rTSA). Improvements in outcome using each metric score were calculated and normalized on a 100 point scale. The rate of improvement was analyzed using a 40 point moving filter treadline and with a 3rd order polynomial treadline over the entire range of follow-up.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 148 - 148
1 Jan 2016
Gao B Angibaud L Johnson D
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Introduction

Total knee arthroplasty (TKA) implant systems offer a range of sizes for orthopaedic surgeons to best mimic the patient's anatomy and restore joint function. From a biomechanical perspective, the challenge on the TKA implants is affected by two factors: design geometry and in vivo load. Larger geometry typically means more robust mechanical structure, while higher in vivo load means greater burden on the artificial joint. For an implant system, prosthesis geometry is largely correlated with implant size, while in vivo load is affected by the patient's demographics such as weight and height. Understanding the relationships between implant size and patients' demographics can provide useful information for new prosthesis design, implant test planning, and clinical data interpretation. Utilizing a manufacturer supported clinical database, this study examined the relationships between TKA patient's body weight, height, and body mass index (BMI) and the received implant size of a well-established implant system.

Methods

A multi-site clinical database operated by Exactech, Inc. (Gainesville, FL, USA) was utilized for this study. The database contains patient information of Optetrak TKA implant recipients from over 30 physicians in US, UK, and Colombia since 1995. Nine implant sizes (0, 1, 2, 2.5, 3, 3.5, 4, 5 and 6) are seen in the database, while size 0 was excluded due to very low usage. Taking primary TKA only, a total of 2,713 cases were examined for patient's body weight, height, BMI, and their relationships with the implant size.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 147 - 147
1 Jan 2016
Gao B Angibaud L Johnson D
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Introduction

Cruciate Retaining (CR) and Posterior Stabilizing (PS) are two common types of total knee arthroplasty (TKA) surgeries. The CR approach preserves the posterior cruciate ligament (PCL) while the PS approach sacrifices it. Implant size selection during a TKA surgery is primarily driven by the patient's bone size, but could also be affected by surgery types due to the influence of the PCL. The objective of this study was to investigate the effect of TKA surgery type on implant size selection, based on the clinical database of a well-established commercial implant system.

Methods

A clinical database operated by Exactech, Inc. (Gainesville, FL, USA) was utilized for this study. The database contains TKA patient information of Optetrak® implant recipients from over 30 physicians in the US, UK, and Colombia since 1995. Patient height was used as a control factor for comparison of surgery types, and categorized by every 10 cm (e.g., the “170 cm” category contains patients from 170 to 179 cm). Taking primary TKA only and body heights from 130 cm to 199 cm, a total of 2,677 cases were examined. No statistical difference exists on patients' gender, body weight, or BMI within every height category between the CR and PS groups. The femoral implant size and tibial insert thickness were compared between the two groups.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIX | Pages 85 - 85
1 Jul 2012
Jain R Majid I Liu A Jones R Johnson D
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Aim

To determine the tensile forces across the knee extensor mechanism during walking, in simulated conditions of treatment.

Methods

Gait analysis of six normal subjects was performed, with full weight bearing unilateral immobilisation of the knee during walking. Measurements were taken without then with a brace, unlocked then locked at 0°, 0-10°, 0-20° and 0-30° of flexion. Mean and maximum knee flexion angles were measured, followed by calculation of the mean and maximum forces across the extensor mechanism during loading, supporting and propulsion phases of gait.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XVIII | Pages 17 - 17
1 May 2012
Khan W Dheerendra S Johnson D Andrew J Hardingham T
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INTRODUCTION

Bone marrow derived mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. Hypoxia has been shown to improve chondrogenesis in adult stem cells. In this study we characterised bone marrow derived stem cells and investigated the effects of hypoxia on gene expression changes and chondrogenesis.

MATERIALS AND METHODS

Adherent colony forming cells were isolated and cultured from the stromal component of bone marrow. The cells at passage 2 were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium under normoxic (20% oxygen) or hypoxic (5% oxygen) conditions for 14 days. Gene expression analysis, glycosoaminoglycan and DNA assays, and immunohistochemical staining were determined to assess chondrogenesis.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XVIII | Pages 68 - 68
1 May 2012
Khan W Dheerendra S Johnson D Andrew J Hardingham T
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Introduction

Mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. We have previously demonstrated that the infrapatellar synovial fat pad is a rich source of mesenchymal stem cells and these cells are able to undergo chondrogenic differentiation. Although synovial fat pad derived mesenchymal stem cells may represent a heterogenous population, clonal populations derived from the synovial fat pad have not previously been studied.

Materials and Methods

Mesenchymal stem cells were isolated from the infrapatellar synovial fat pad of a patient undergoing total knee arthroplasty and expanded in culture. Six clonal populations were also isolated before initial plating using limiting dilution and expanded. The cells from the mixed parent population and the derived clonal populations were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium for 14 days. Gene expression analyses; glycosoaminoglycan and DNA assays; and immunohistochemical staining were determined to assess chondrogenic responses.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IX | Pages 81 - 81
1 Mar 2012
Khan W Dheerendra S Johnson D Andrew J Hardingham T
Full Access

INTRODUCTION

Bone marrow derived mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. Hypoxia has been shown to improve chondrogenesis in adult stem cells. In this study we characterised bone marrow derived stem cells and investigated the effects of hypoxia on gene expression changes and chondrogenesis.

MATERIALS AND METHODS

Adherent colony forming cells were isolated and cultured from the stromal component of bone marrow. The cells at passage 2 were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium under normoxic (20% oxygen) or hypoxic (5% oxygen) conditions for 14 days. Gene expression analysis, glycosoaminoglycan and DNA assays, and immunohistochemical staining were determined to assess chondrogenesis.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IX | Pages 82 - 82
1 Mar 2012
Khan W Dheerendra S Johnson D Andrew J Hardingham T
Full Access

Introduction

Mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. We have previously demonstrated that the infrapatellar synovial fat pad is a rich source of mesenchymal stem cells and these cells are able to undergo chondrogenic differentiation. Although synovial fat pad derived mesenchymal stem cells may represent a heterogenous population, clonal populations derived from the synovial fat pad have not previously been studied.

Materials and Methods

Mesenchymal stem cells were isolated from the infrapatellar synovial fat pad of a patient undergoing total knee arthroplasty and expanded in culture. Six clonal populations were also isolated before initial plating using limiting dilution and expanded. The cells from the mixed parent population and the derived clonal populations were characterised for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium for 14 days. Gene expression analyses; glycosoaminoglycan and DNA assays; and immunohistochemical staining were determined to assess chondrogenic responses.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IX | Pages 42 - 42
1 Mar 2012
Hakimi M Anand S Sahu A Johnson D Turner P
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The aim of this study was to determine current practice in anterior cruciate ligament reconstruction amongst BASK members. This was an internet-based survey where members were invited to complete a questionnaire on ACL reconstruction.

Of the 365 BASK surgeons performing ACL reconstruction, 241 completed the questionnaire (response rate 66%). 147(61%) of surgeons used both hamstring and patellar tendon grafts, 71(29%) used only hamstrings and 21(9%) used patellar tendon only. All surgeons used ipsilateral autograft.

157 (65%) used the transtibial technique for femoral tunnel placement with 80(33%) using the anteromedial portal technique. Of those using the anteromedial portal, the most common femoral fixation devices were the Endobutton (34%) and RCI screw (34%). Interference screw fixation (81%) was the most common tibial fixation in the same group of surgeons with the RCI screw being the most common (63%). 19% (45/241) of surgeons were performing double bundle ACL reconstructions in select cases.

Hamstring femoral fixation was with a suspension device in 79% and interference screw in 18%. Of those using a suspension device the Endobutton was most common (48%) followed by Transfix (26%) and Rigidfix (19%). Tibial fixation was most commonly achieved by interference screw (57%) followed by Intrafix (30%).

With patellar tendon graft the most popular femoral fixation was with an interference screw (66%) followed by suspension (34%). All surgeons used interference screw for tibial fixation.

90% of surgeons (217) allow immediate full weight-bearing as tolerated irrespective of fixation type with 8% delaying full weight bearing between 1 and 3 weeks. The results show the wide spread of variation in practice of ACL reconstruction. With recent renewed interest in a more anatomic placement of tunnels, the use of the anteromedial portal may continue to increase. With such a wide variation in techniques, grafts and fixation implants used, a register may help assess outcomes.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 454 - 454
1 Nov 2011
Dennis D Johnson D Kindsfater K Kim R
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Introduction: Obtaining accurate anatomic and mechanical alignment in total knee arthroplasty (TKA) is correlated with improved long-term results. Whether computer-assisted total knee arthroplasty (CAS-TKA) more reliably produces a neutral mechanical and anatomic alignment and improves functional outcomes over traditional total knee arthroplasty (T-TKA) remains debatable. This report evaluates the results of CAS-TKA vs. T-TKA in a series of patients who underwent bilateral TKA performed at the same surgical operation.

Methods: Sequential bilateral TKA were performed on 36 patients utilizing CAS-TKA in one knee and T-TKA in the contralateral knee by two high volume, fellowship trained surgeons. A review and statistical analysis of prospectively collected data was performed after a mean follow-up of 2.2 years.

Results: Knee Society Scores (KSS) improved from 42.9 to 96.3 in the CASTKA group vs. 46.0 to 94.8 in the T-TKA group. Range of motion (ROM) improved from 116.8° to 126.9° in the CAS-TKA group vs. 118.3° to 125.4° in the T-TKA group.

With numbers available, there were no differences between the groups with regard to change in KSS (p=0.38), ROM (p=0.42), mean postoperative anatomic alignment (5.78° vs. 5.50°, p=0.37), femoral angle (5.56° vs. 5.61°, p=0.84), or tibial angle (89.89° vs.

89.69°, p=0.46). There was a non-significant trend towards fewer outliers in the CASTKA group with respect to anatomic alignment (2.8% vs. 13.9%, p=0.09) and tibial angle (0% vs. 5.6%, p=0.46).

Conclusion: There is not an apparent benefit to the use of CAS-TKA with regards to KSS, ROM, or alignment in the hands of high-volume, fellowship-trained total joint specialists. The clinical relevance of the non-sig-nificant trend towards fewer outliers in the CAS-TKA group is unknown at the current follow-up interval. These results may not preclude the benefits of CAS-TKA in lower-volume or less experienced TKA surgeons.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 413 - 414
1 Nov 2011
Dennis D Kim R Johnson D Springer B Fehring T Rullkoetter P Laz P Baldwin M
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Introduction: Patellar crepitus (PC) has been reported in 13% of cruciatesubstituting total knee arthroplasty (TKA) patients resulting from synovial tissue impingement within the femoral component intercondylar box (IB). Patient factors, component design, and technical errors have been implicated in PC. We compared primary TKA patients with PC requiring surgery against matched controls to identify significant variables.

Methods: The databases of 2 institutions were reviewed to identify patients requiring surgery for PC. A control group matched for age, sex, and BMI was identified.

Patient charts and radiographs were reviewed. Statistical analysis was performed.

Significant variables associated with patient anatomy, implant size and alignment were subsequently investigated in a computational model to evaluate tendofemoral contact.

Results: Between 2002 and 2008, over 4000 primary TKAs were performed using the Press Fit Condylar Sigma (DePuy, Warsaw, Indiana) TKA. Of these, 59 knees developed PC requiring surgery. The mean time to presentation was 10.9 months. The incidence of PC correlated with greater number of previous surgeries (1.18 vs. 0.44, p= 0.002), decreased patellar button size (35.7 vs. 37.1mm, p=0.003), shorter patellar tendon length (54.5 vs. 57.9mm, p=0.01), and increase in posterior femoral condylar offset (1.27mm vs. 0.17mm, p=0.022). Using a patellar component of 32 or 35mm significantly increased the risk of PC compared to the use of a 38 or 41mm component (p< 0.01, RR=1.61, OR 2.63). Modeling results demonstrated decreased patellar tendon length created increased tendofemoral contact near the IB, while larger buttons increased separation between the tendon and the box edge.

Conclusion: Shortened patellar tendon length and use of smaller patellar components may expose the quadriceps tendon to increased irritation as it traverses across the femoral component IB. Increasing posterior femoral offset may increase quadriceps tendon tension, further risking synovial tissue impingement within the IB.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 314 - 314
1 Jul 2011
Khan W Malik A Anand S Johnson D Andrew J Hardingham T
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Introduction: There is an ever-increasing clinical need for the regeneration and replacement of tissue to replace soft tissue lost due to trauma, disease and cosmetic surgery. A potential alternative to the current treatment modalities is the use of tissue engineering applications using mesenchymal stem cells that have been identified in many tissues including the fat pad. In this study, stem cells isolated from the fat pad were characterised and their differentiation potential assessed.

Materials and Methods: The infrapatellar fat pad was obtained from total knee replacement for osteoarthritis. Cells were isolated, expanded and stained for a number of stem cell markers. For adipogenic differentiation, cells were cultured in adipogenic inducing medium (10ug/ml insulin, 1uM dexamthasone, 100uM indomethacin and 500uM 3-isobutyl-1-methyl xanthine). Gene expression analyses and Oil red O staining was performed to assess adipogenesis.

Results: Cells at passage 2 stained strongly for CD13, CD29, CD44, CD90 and CD105 (mesenchymal stem cell markers). The cells stained sparsely for 3G5 (peri-cyte marker). On gene expression analyses, the cells cultured under adipogenic conditions had almost a 1,000 fold increase in expression of peroxisome proliferator-activated receptor gamma-2 (PPAR gamma-2) and 1,000,000 fold increase in expression of lipoprotein lipase (LPL). Oil red O staining revealed triglyceride accumulation within typical adipogenic morphology, confirming the adipogenic nature of the observed vacuoles, and showed failure of staining in control cells.

Discussion: Fat pad derived stem cells expressed a cell surface epitope profile of mesenchymal stem cells, and exhibited the potential to undergo adipogenic differentiation. Our results show that the human fat pad is a viable potential autogeneic source for mesenchymal stem cells capable of adipogenic differentiation as well as previously documented ostegenic and chondrogenic differentiation. This cell source has potential use in tissue engineering applications.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_III | Pages 278 - 278
1 Jul 2011
Lopez-Vidriero E Ayeni OR Rupke T Nasser AB Johnson D
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Purpose: To present our clinical and quality of life outcomes after one year treatment with our protocol including graft retention.

Method: Seventeen of 1, 847 patients who underwent ACL reconstruction surgery were identified as infected following retrospective chart review in our institution (University of Ottawa) from 1995 to 2005. Mean age was 37 years old (range 18–56). Gender ratio was 14 male/ three female. Laterality 13 left/ four right knees. The diagnosis was achieved by clinical suspicion and serum markers (ESR, CPR, WBC) followed with aspiration and culture of intraarticular liquid. After that, our treatment protocol included IV antibiotics (empiric and culture guided) and knee arthroscopy performing debridement and lavage with 12L of saline irrigation as well as graft retention when possible. Clinical and Radiographic data were collected at a minimum of one year follow-up (IKDC, KT-1000, Lysholm, SF-12, Tegner, Cybex Strength testing).

Results: The Incidence of septic arthritis following ACL reconstruction was 0, 92%. Bacteriology results were as follows: seven staphylococcus aureus, four Propionibac-terium acnes, one Klebsiella oxytoca, five no growth. The time from ACL reconstruction to first symptoms of infection was 37 days (range 4–63). The time from symptoms to arthroscopic debridement was 5, 5 days (range 0–33). Serology markers were as follows: ESR mean 69 (range 23–128), CPR 136 (50–387), WBC 10.3 (6–15). The average follow up was 41 months (range 12–85). Sixteen of 17 grafts were retained after 1.53 procedures per patient. Antibiotic treatment lasted 5.2 weeks on average. The average clinical outcomes were: Lysholm 77 (44–98), IKDC 74 (46–95), Quadriceps strength 71 % of non operative side, and Hamstrings strength 70 % of non operative side, KT -1000 side to side difference 1 mm (−3 to 4). Degenerative radiological changes were noted in three patients. Two later repeat reconstructions occurred due to instability (11,1%). No delayed recurrence of infection was noted.

Conclusion: ACL reconstruction is a safe procedure being the incidence of septic arthritis in our series of 0, 92%. Our protocol of treatment is clinically effective and allows for a stable knee in 88, 9% of the patients avoiding the appearance of a delayed infection.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 14 - 14
1 Jan 2011
Yarashi T Sahu A Rutherford J Anand S Johnson D
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We aim to create a set of reference data of commonly used scoring systems in the normal population, and to compare these results with published postoperative scores for commonly performed knee operations. This was a questionnaire-based study and a total of 744 questionnaires were sent out, of which 494 replies were received. Six scoring systems were addressed: Lysholm and Oxford Knee Scores, Tegner and UCLA activity scales and Visual Analogue Scales (VAS) for both pain and function. Data was collected into groups based on age (20–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89 years). The reference data obtained was then compared to published postoperative scores for knee arthroplasty and ACL reconstruction, to assess whether these patients did indeed return to “normal”.

The mean scores for sequential age groups (described above) were as follows: Oxford Knee Score – 13, 13, 14, 14, 17, 15, 17; Lysholm Knee Score – 96, 95, 92, 89, 89, 89, 79; Tegener Activity Scale – 6, 5, 5, 4, 4, 3, 3; UCLA Activity Scale – 8, 7, 7, 7, 6, 6, 5; VAS pain – 5, 8, 10, 9, 14, 12, 20; VAS function 96, 95, 90, 90, 86, 84, 84. Symptom based scoring systems (Oxford Knee Score, Lysholm) were independent of age whereas activity scores (Tegner, UCLA) decreased with age. There was no significant difference detected between scores in different sexes in the same age group. Compared to published scores in an age-matched population following TKR, the data obtained showed that patients do not return to normal scores following arthroplasty. Following ACL reconstructive surgery, activity scores were higher than compared to the data obtained from our population.

Data generated from this study can be used as reference data and can play an important role in interpreting post-intervention scores following knee surgery.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_I | Pages 15 - 15
1 Jan 2011
Rutherford J Mulgrew E Johnson D Turner P
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Complex primary total knee replacements have been poorly reported in the literature We review all complex primary total knee replacement procedures at Stepping Hill Hospital. Patients underwent knee examination, knee scores, notes review and pre- and post-operative radiograph review. There were 29 patients with 36 knees that had a complex primary total knee replacement. Most frequent indications for surgery were osteoarthritis, rheumatoid arthritis or following trauma. Mean age at surgery 70 years. The prosthesis used were : 3 Stryker Kinemax; 32 De Puy PFC and one rotating hinge. Complex Primary Oxford knee score; preoperative mean 45 (range 33 to 57); postoperative mean 26 (range 14 to 53). NJR Total Knee Replacement Oxford knee score postoperative mean 30. Mean visual analogue scores; pain in the knee, mean 19; knee function, mean 77; outcome of the operation 76; satisfaction with the surgery 87. Mean length of hospital stay 13 days.

Using the Knee Society Radiographic Scoring System, there were no signs that need to be monitored or signify failure. Seven patients were transfused postoperatively, four patients had minor wound problems, three required further surgery, two to washout the knee and exchange the polyethylene liner, one femoral plating to stabilise an osteotomy site. Long term complications : one above knee amputation for infection, one foot drop.

Revision implants can be used in complex primary knee replacements, and pose technical difficulties but address various pathologies. The surgery is associated with an increased risk of complications and transfusion. Clinical scores at least match scores for routine total knee replacements, patient satisfaction is excellent.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_IV | Pages 498 - 499
1 Oct 2010
Sahu A Johnson D Turner P Wilson T
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Introduction: To train the surgeon adds to the length of procedures and this is currently not accounted for, in the finance received to perform the operation by the hospital.

Objective: Our study focussed on these main questions:

What is the effect on the length of a procedure when a trainee is involved?

What is the effect on the length of a list and the number of procedures performed on the list when a trainee is involved?

What percentage of cases had trainee involvement for anaesthetics and surgery?

Is this is statistically significant?

Method: Data was taken from two different sources, firstly, the ORMIS theatre system and patient operation notes. These were used to determine the length of six different types of orthopaedic procedures and the level of the main surgeon. This was collected in Stepping Hill hospital, Stockport, United Kingdom between June and July 2008. The second source used was a consultant’s logbook comprising 227 primary total knee replacements between 2004 and 2008.

Results: The data collected via the ORMIS system produced trends suggesting trainees took longer to perform procedures than consultants. The data from the consultant logbook statistically proved this. List times appeared unaffected by trainee presence. In Orthopaedic surgeries, 92% times trainees were present during the procedure and out of this 17% cases were performed by trainees. For total hip replacements done by trainees the procedure took significantly longer surgical time than consultant performed procedures (p = 0.0337).

Among these cases, 71% were performed by senior trainees. The consultant’s log book data also suggested the similar trends. In all comparisions, time taken by trainees to perform surgeries were statistically significant. Trainee performed with consultant scrubbed versus consultant performed (P = < 0.0001), trainee performed with consultant in theatre versus consultant performed(P = 0.0318) and trainee performed with consultant scrubbed versus trainee performed with consultant in theatre (P = 0.002)

Discussion and Conclusion: Hospitals are paid a fixed fees per operation due to introduction of payment by results system as they are paid a fixed tariff for a particular procedure. Training increases the length of a procedure and therefore in an efficient structured environment prevents as many cases being done on a list. Therefore, training future surgeons costs the hospital money. To counter this, training hospitals should be given financial incentives to train in surgery, or procedures performed by trainees should be priced differently to account for the time lost by training.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_IV | Pages 608 - 609
1 Oct 2010
Sahu A Cheetham W Forshaw W Johnson D Watson E
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Introduction: The Rhys-Davies exsanguinator is a commonly used tool for exsanguinating upper or lower limbs in orthopaedic surgery. The use of same exsanguinators on a repetitive basis can cause cross contamination. This study was aimed at looking at the contamination of the Rhys-Davies exsanguinators in our hospital and comparing the results after cleaning it with a disinfectant wipe.

Materials and Methods: We used two standard methods to measure the contamination levels of the Rhys-Davies exsanguinators. In first method, we used rapid microbial ATP bioluminescence assay to detect contamination before and after cleaning of these exsanguinators. We did this test at four specified sites (outer top, outer bottom, inside top and inside bottom) after clearly marking them. Our second method was taking samples and using standard agar plates from the 24 sites of these 6 Rhys-Davies exsanguinators. We repeated the assay as well the swabs from all the sites, after cleaning these exsanguinators with Sani Cloth 70 Alcohol Wipes. We incubated these samples at 37 deg cel for 48 hours and kept them in enrichment cultures for 7 days.

Results: All sampled Rhys-Davies exsanguinators were heavily contaminated as revealed by both the methods. On bioluminescence assay, in some exsanguinators the count was 100 times more than normal (acceptable value is 30). Similarly all exsanguinators were colonised with bacterial count varying from 8 to > 350. Coagulase negative staphylococcus was the most commonly grown organism from the exsanguinators. After cleaning these tourniquets with Sani Cloth Wipes, there was 95% reduction in bioluminescence assay and 99% reduction in contamination from colony growth point of view, which is statistically significant (P=0.02).

Conclusion: Nine percent of hospital in-patients are believed to acquire an infection after their admission to hospital. Different organisms can raise different levels of concerns. Coagulase negative Staphylococcus from a skin swab is normal but it can be a major source for surgical site infections. The presence of any number of such organisms around a surgical site can be worrying. The presence of a single colony of other pathogenic organisms such as MRSA, Coliforms or Pseudomonas can be alarming if found on these devices. This study suggests that mechanical decontamination by cleaning with sani cloth wipes, then leaving it to dry completely for 15 minutes might reduce the level of contamination of these devices. Use of rapid R-mATP assay has added strength to our study as it requires only 5 min to complete, including sampling. This screening method can be used randomly to check whether protocols are being properly followed, regarding decontamination of such devices.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_III | Pages 409 - 409
1 Jul 2010
Sahu A Wilson T Anand S Johnson D Turner P
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Purpose of the study: What is the effect on the length of a procedure and the number of procedures performed on the list when a trainee is involved? What percentage of cases had trainee involvement for orthopaedic surgery?

Methods: Data was taken from two different sources, firstly, the ORMIS theatre system and patient operation notes. These were used to determine the length of six different types of orthopaedic procedures and the level of the main surgeon. The second source used was a consultant’s logbook comprising 227 primary total knee replacements between 2004 and 2008.

Results: The data collected via the ORMIS system produced trends suggesting trainees took longer to perform procedures than consultants. The data from the consultant logbook statistically proved this. List times appeared unaffected by trainee presence. In Orthopaedic surgeries, 92% times trainees were present during the procedure and out of this 17% cases were performed by trainees. For total knee replacements done by trainees the procedure took significantly longer surgical time than consultant performed procedures (p = 0.0337).

Among these cases, 71% were performed by senior trainees. The consultant’s log book data also suggested the similar trends. Statistically, trainee performed with consultant scrubbed versus consultant performed (P = < 0.0001), trainee performed with consultant in theatre versus consultant performed(P = 0.0318) and trainee performed with consultant scrubbed versus trainee performed with consultant in theatre (P = 0.002)

Discussion & Conclusion: To train the surgeon adds to the length of procedures and this is currently not accounted for, in the finance received to perform the operation by the hospital.

To counter this, training hospitals should be given financial incentives to train in surgery, or procedures performed by trainees should be priced differently to account for the time lost by training.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_III | Pages 409 - 409
1 Jul 2010
Sahu A Nazary N Harshavardana N Anand S Johnson D
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Purpose: Our aim of this study was to find out the abstract to publication ratio (APR) in peer-reviewed indexed journals of abstracts presented at BASK annual meetings. We also wanted to identify the publishing journals and to look at the amount of time taken for publication.

Methods: We obtained permission from BASK executive committee and retrieved all presentations (podium & poster) over six year period (2000–2005). An extensive PubMed database search was performed to determine whether or not the abstract had been published as a full paper up to the beginning of Nov 2008.

Results: A total of 294 abstracts identified, 114 of them were published as 101 full-text articles in 21 different journals. ‘The Knee’ Journal was the most popular destination with 47 publications (41.2%) followed by JBJS (British) with 28 publications (24.5%). The overall abstract to publication ratio (APR) at BASK annual meetings was 38.77%. The mean duration between presentations to publication was 3.96 yrs (range 0 to 7.2 yrs, median 3.4 yrs).

Conclusion: On bench marking the APR ratio at BASK presentations, it is comparable with those of BOA (33.1%), other BOA affiliated societies (26–50%) and medical specialties (32–66%). Abstract to publication ratio (APR) is considered as a measure of the quality of scientific meetings and our results indicates the higher credentials of BASK meetings. It is very difficult to exactly determine the reason for abstracts failing to indexed publications; it is arguable that some of these projects did not meet the scientific scrutiny of the peer-review process required for full publication. We recommend authors to submit the full manuscript of paper after acceptance of their abstracts for the BASK meeting as done in AAOS meeting in order to encourage them to complete their manuscript before presentation.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 59 - 59
1 Mar 2010
Khan* W Anand S Tew S Johnson D Andrew J Hardingham T
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There is an ever-increasing clinical need for the regeneration and replacement of tissue to replace soft tissue lost due to trauma, disease and cosmetic surgery. A potential alternative to the current treatment modalities is the use of tissue engineering applications using mesenchymal stem cells that have been identified in many tissue including the infrapatellar fat pad. In this study, stem cells isolated from the infrapatellar fat pad were characterised to ascertain their origin, and allowed to undergo adipogenic differentiation to confirm multilineage differentiation potential.

The infrapatellar fat pad was obtained from total knee replacement for osteoarthritis. Cells were isolated and expanded in monolayer culture. Cells at passage 2 stained strongly for CD13, CD29, CD44, CD90 and CD105 (mesenchymal stem cell markers). The cells stained poorly for LNGFR and STRO1 (markers for freshly isolated bone marrow derived stem cells), and sparsely for 3G5 (pericyte marker). Staining for CD34 (haematopoetic marker) and CD56 (neural and myogenic lineage marker) was negative. {BR}For adipogenic differentiation, cells were cultured in adipogenic inducing medium consisting of basic medium with 10ug/ml insulin, 1uM dexamthasone, 100uM indomethacin and 500uM 3-isobutyl-1-methyl xanthine. By day 16, many cells had lipid vacuoles occupying most of the cytoplasm. On gene expression analyses, the cells cultured under adipogenic conditions had almost a 1,000 fold increase in expression of peroxisome proliferator-activated receptor gamma-2 (PPAR gamma-2) and 1,000,000 fold increase in expression of lipoprotein lipase (LPL). Oil red O staining confirmed the adipogenic nature of the observed vacuoles and showed failure of staining in control cells.

Our results show that the human infrapatellar fat pad is a viable potential autogeneic source for mesenchymal stem cells capable of adipogenic differentiation as well as previously documented ostegenic and chondrogenic differentiation. This cell source has potential use in tissue engineering applications.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 427 - 427
1 Sep 2009
Yarashi T Rutherford J Kapoor A Anand S Johnson D
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AIM: To create a set of reference data of commonly used scoring systems in the normal population, and to compare these results with published postoperative scores for commonly performed knee operations.

METHODS: This was a questionnaire-based study and a total of 657 questionnaires were sent out, of which 407 replies were received. A further 159 were excluded due to ongoing knee problems or previous knee surgery. Six scoring systems were addressed: Lysholm and Oxford Knee Scores, Tegner and UCLA activity scales and Visual Analogue Scales (VAS) for both pain and function. Data was collected into groups based on age (20–29, 30–39, 40–49, 50–59, 60–69, 70–79, 80–89 years). The reference data obtained was then compared to published postoperative scores for knee arthroplasty and ACL reconstruction, to assess whether these patients did indeed return to “normal”.

RESULTS: The mean scores for sequential age groups (described above) were as follows: Oxford Knee Score – 13, 14, 14, 14, 17, 15, 19; Lysholm Knee Score – 95, 92, 92, 90, 88, 90, 79; Tegener Activity Scale – 5, 5, 5, 4, 4, 3, 3; UCLA Activity Scale – 9, 7, 7, 7, 6, 6, 5; VAS pain – 2, 9, 9, 9, 14, 12, 20; VAS function 97, 94, 92, 90, 86, 86, 83. Symptom based scoring systems (Oxford Knee Score, Lysholm) were independent of age. Activity scores (Tegner, UCLA) showed a statistically significant decrease with age. There was no significant difference detected between scores in different sexes in the same age group. Compared to published scores in an age-matched population following TKR, the data obtained showed that patients do not return to normal scores following arthroplasty. Following ACL reconstructive surgery, activity scores were higher than compared to the data obtained from our population.

CONCLUSIONS: Data generated from this study can be used as reference data and can play an important role in interpreting post-intervention scores following knee surgery.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 32 - 32
1 Mar 2009
Howcroft D Fehily M Peck C Fox A Dillon B Johnson D
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Templating of preoperative radiographs is routinely recommended prior to knee arthroplasty. We performed this study to assess the reproducibility and accuracy of the templates for three commonly used knee implants (PFC, Kinemax, Scorpio). Six lower limb surgeons templated 10 patients for each of the three designs. The inter and intra-observer reliability and accuracy was calculated. There was marked variation in the reliability of the templating with the tibial insert scoring better than the femoral and the Kinemax being the most reproducible of the three. In general, the intra-observer scores (κ= 0.57–0.81) were better than the inter-observer ones (κ= 0.21–0.60). The Scorpio was the most accurately templated of the three implants, with the percentage correlating with what was actually implanted ranging from 55–62% for the femur and 72–75% for the tibia, with no templated sizes more than 1 size different from the actual implant. The other implants ranged from 38–42% for the femur and 53–58% for the tibia with both having up to 3% more than 1 size difference from the actual implant. We believe that the use of templating in total knee arthroplasty should be interpreted with caution and we urge the development of more accurate prosthesis sizing techniques.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 323 - 323
1 Jul 2008
Khan W Jones R Nokes L Johnson D
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Introduction: In this study the optimal angle of fixation or splintage for partially weight bearing fractures of the patella was determined by a gait analysis measurement system.

Subjects and Methods: A knee brace was applied to eight subjects and locked at 0, 10, 20 and 30 degrees. Measurements were also taken for an unlocked brace and in the absence of a brace. The subjects were instructed on partial weight bearing mobilisation. Three dimensional motion analyses were performed using an infrared 8-camera system. The ground reaction force was recorded by two 3-dimensional force plates embedded in the walkway. Kinematic and kinetic data was collected and the data was transferred to a computer programme for further analysis and the forces acting on the patella were calculated.

Results: The results showed that the forces acting on the patella were directly proportional to the knee flexion angle. The results also showed that the knee flexion angle does not always correspond with the angle set at the knee brace; however they did exhibit a direct relationship.

Conclusion: Our findings show that, for partially weight bearing patella fractures, the optimum form of splintage corresponds with a low knee flexion angle.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 373 - 373
1 Jul 2008
Khan W Jones R Nokes L Johnson D
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Patella and extensor mechanism injuries are common injuries and are generally managed with some degree of immobilisation and partial weight bearing to facilitate healing. The aim of this project was to determine the type of immobilisation or splintage during partial weight bearing that results in minimal forces acting through the extensor mechanism.

Gait analysis studies were performed on eight healthy male subjects mobilising partially weight bearing. Measurements were taken for six types of immobilisation: locked at 0, 10, 20, 30 degrees and unlocked in an orthotic knee brace, and without a brace. The ground reaction force, knee joint angle and the knee flexion moment were measured using Qualisys Track Manager and Visual 3D Software. The extensor mechanism moment and the extensor mechanism force were calculated using static equilibrium equations and documented data. A one-way analysis of variance statistical test was performed to determine the statistical significance of the differences between the six types of immobilisation.

There was a direct relationship between the knee flex-ion angle and the extensor mechanism force. The extensor mechanism force at 0 degrees of immobilisation was significantly lower than that for 20 and 30 degrees (p< 0.05). The increase in the extensor mechanism moment arm with increasing knee flexion was not suf-ficient to offset the increase in the extensor mechanism force caused by the increase in the knee flexion moment. The results also showed that the knee flexion angle does not always correspond with the angle set at the knee brace; however they did exhibit a direct relationship.

These results have important implications for the management of patients with patella and extensor mechanism injuries. The results suggest that improvements in knee brace design to allow 0 degrees of knee flexion, rather than the 10 degrees as seen in this study, are likely to result in significantly reduced extensor mechanism tensile forces.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 308 - 308
1 Jul 2008
Thomas C Bhutta M Johnson D
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Introduction: The aim of this study was to assess the practice of obtaining informed consent for Total Hip Replacement Surgery in the United Kingdom.

Methods and results: 1571 consultant members of the BOA were surveyed by postal questionnaire regarding their practice towards obtaining informed consent for total hip replacement surgery. 524 (33.3%) replies were received. 368 (23.4%) of the 524 consultants who replied still performed total hip replacement surgery. In obtaining informed consent for hip replacement surgery consultants warned of the following complications: Infection 99.7%, Dislocation 98.9%, Leg length discrepancy 75.2%, Aseptic loosening 85.8%, neurovascular damage 61.9%, Wear 63.2%, DVT 96.0%, PE 89.0% and Mortality 71.6%. Consent was routinely obtained by Senior House Officers in 38.7%, by Pre-Registration House Officer in 3.8% and by specialist nurses in 5.4% of cases. Patient information leaflets were provided by 72.0% of consultants for Hip Replacement.

Discussion: We recommend national guidelines relating to obtaining consent for hip replacement should be published by the British Hip Society. This should be incorporated into their best practice documents regarding Hip replacement Surgery. Consent should also be obtained by a suitably experienced practitioner.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_II | Pages 324 - 324
1 Jul 2008
Khan W Johnson D Andrew J Hardingham T
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Introduction: In this study infrapatellar fat pad (IPFP) derived stem cells were expanded with and without Fibroblast Growth Factor-2 (FGF-2) supplementation and were compared with regards to their ability to proliferate and differentiate into chondrocytes.

Materials and Methods: Cells were isolated from the IPFP tissue and expanded in monolayer culture with and without rhFGF-2 supplementation (final concentration 10ng/ ml). Cell aggregates were placed in chondrogenic media for two weeks. Gene expression studies were carried out using quantitative real time PCR. Immunohistochemical labelling was performed with antibody localisation determined by an immunoperoxidase procedure. The pellets were also weighed and digested in papain for DNA and glycosoaminoglycan (GAG) analysis.

Results: Cells expanded in FGF-2 supplemented media were smaller and proliferated more rapidly. The FGF-2 supplemented cell aggregates also showed 100 times higher expression of collagen type II (COL2A1). Immunohistochemical studies showed that pellets made from FGF-2 treated cells stained more strongly for collagen II and more weakly for collagen I. Pellets made with FGF-2 treated cells were larger, continued with enhanced proliferation and contained more proteoglycan.

Conclusion: Our findings show enhanced proliferation and chondrogenic differentiation in IPFP derived stem cells expanded in FGF-2 supplemented media.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_I | Pages 109 - 109
1 Mar 2008
Volesky M Pickle A Bessette B Wilkinson R Dervin G Johnson D
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This prospective, randomized clinical comparison of tibial fixation in 4-bundle hamstring ACL reconstruction, evaluated mechanical results (laxity) between BioScrew XtraLok® (Linvatec) and Intrafix® (Mitek Products) at six months. One hundred and three sequential patients undergoing ACL reconstruction by three surgeons with identical technique were recruited. KT-1000 arthrometer manual maximum measurements were taken at six weeks, six and six months post-operatively.

At six weeks and three months, KT-1000 side-to-side differences between the groups are not statistically significant (student-t test, p=0.87 and p=0.34, respectively). In clinical results at six months, tibial fixation with Bioscrew XtraLok has significantly decreased laxity compared to the Intrafix device (p=0.017).

This prospective, randomized clinical comparison of tibial fixation in hamstring ACL reconstruction evaluated mechanical results (laxity) between BioScrew XtraLok® (Linvatec, Largo, FL) and Intrafix® (Mitek Products, Norwood, MA) at six months.

After Ethics Review Board approval and sample-size calculation, one hundred and three sequential patients undergoing ACL reconstruction were recruited. Inclusion criteria were: absence of other ligamentous injury or previous knee surgery, and a normal contralateral knee.

After drilling tunnels, patients were allocated to a study arm (XtraLok® or Intrafix®) by a computer-generated randomization table. In all patients, EndoButton® (Smith & Nephew, Andover, MA) was used for femoral fixation and the Mitek tensioner was employed.

The patients were assessed with KT-1000 arthrometer manual maximum measurements taken at six weeks, three and six months post-operatively by independent clinicians. Mean measurements between the two groups were compared using the student-t test at the above intervals.

At six months, eighty-seven of one hundred and three (84%) patients were available for follow-up; 43 XtraLok (XL), and forty-four Intrafix (IF). There was no significant difference between groups in mean age and gender. KT-1000 arthrometer side-to-side differences at six weeks were 1.04mm (XL) versus 1.14mm (IF), and 0.96mm (XL) versus 1.38mm (IF) at three months. At these intervals, differences between the groups are not statistically significant (p=0.87 and p=0.34, respectively). At six months, KT-1000 side-to-side difference was 1.26mm (XL) versus 2.41mm (IF), which is statistically significant (p=0.017).

In clinical results at six months, ACL fixation with Bioscrew XtraLok shows decreased laxity compared to the Intrafix device.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_III | Pages 425 - 425
1 Oct 2006
Basso O Johnson D Wakeley C Jewell F
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During Anterior Cruciate Ligament reconstruction, using bone- patellar tendon- bone graft, debris can accumulate in the joint. We assessed incidence and potential for complications, described the radiographic appearance and defined the natural history of these intrarticular debris in 50 consecutive reconstructions. The records and radiographs of 50 consecutive cases were reviewed. A stripe of radio-opaque material, resembling a comma, termed the “comma” sign, was noted behind the lateral femoral condyle on the early postoperative radiographs of 40 of the 50 cases. There was no statistically significant difference in loss of knee motion at six, twelve, twenty- six and fifty- two weeks postoperatively (P> 0.50) between the patients presenting the radio-opacity and those without it. A second set of radiographs was taken in 12 patients between 3 and 18 months postoperatively, revealing that this radio- opaque material was visible in 1 case only. No correlation was found between presence of radio- opacities and duration of pain, effusion, analgesia requirement, discharge timing, time to driving and time to work. A protocol of postoperative early weight- bearing mobilisation had been followed in all cases which may have played a role in promoting the faster dissolution of the debris.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_II | Pages 253 - 253
1 May 2006
Bhutta M Thomas C Johnson D
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Purpose: The aim of this survey was to assess the practice of obtaining informed consent for Total Knee Replacement Surgery in the United Kingdom.

Method: A postal questionnaire was distributed to consultant members of the British Orthopaedic Association. They were questioned regarding their practice for obtaining informed consent for Total Knee Replacement Surgery.

Results: Of the 1571 consultant members contacted 34% (526) replied. From these 76% (400) performed total knee replacements. Informed consent was obtained in a pre-operative assessment clinic in 64%, on admission in 32.5% and during the first clinic visit in 3.5% of cases. Consent was routinely obtained by Consultants in 76%, Senior House Officers in 38%, Pre-Registration House Officers in 4% and Specialist Nurses in 5% of cases. Consultants warned of the following complications: Infection 99.2%, Stiffness 70.5%, Aseptic loosening 81.6%, neurovascular damage 56.9%, DVT 96.5%, PE 88.5%, Wear 61.2% and Mortality 67.4%. Patient information leaflets were provided by 71.5% of consultants for Total Knee Replacement.

Conclusions: This survey has identified inconsistencies in the complications described to patients. Junior practitioners are continuing to obtain informed consent. Informed consent should be obtained by a suitably experienced practitioner. Patient information leaflets should be provided to patients at the time of listing. We recommend national guidelines relating to obtaining consent for Total Knee Replacement should be published by the BASK. These could be incorporated into their best practice document regarding Total Knee Replacement Surgery.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_II | Pages 153 - 153
1 Apr 2005
Hossain S Hinduja K Mumtaz H Cullen C Turner P Johnson D
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Periarticular fractures of the proximal tibia are some of the most difficult fractures to manage as open reduction and internal fixation of the fractures is plagued with complications such as non-union, delayed union, infection and post-traumatic osteoarthritis.

We evaluated the results of 16 consecutive periarticular tibial fractures stabilised with the AO hybrid fixator using the Oxford Knee Score, American Orthopaedic Foot and Ankle Score (AOFAS) and X-rays of the tibia. Two patients were lost to follow up and 1 patient refused to take part in the study whose latest radiographs showed grade 4 degenerative changes.

The mean follow up was 34 months (range 12 to 57 months) and the mean age was 50 years. All fractures were closed and were graded as either Schatzker 5 or 6. The fixator was applied for an average of 12 weeks. The mean Oxford Knee score was 27.2/60 (mild to moderate knee arthritis) and the mean AOFAS was 71.9/100. There was no significant malunion however 37.5% had developed radiological evidence of grade 3 or 4 post-traumatic osteoarthritis with one requiring a total knee replacement. Forty four percent of patients developed a complication with pin site infection being the commonest complication and 25% required further surgery. There were 2 nonunions with one requiring a fibular osteotomy, which subsequently united.

Eighty eight percent of patients were satisfied with the procedure while 80% would recommend the procedure if required in future.

From our study we feel that hybrid fixation of proximal periarticular tibial fractures is satisfactory however preoperative counselling regarding complications and the possible need for further surgery must be emphasised to the patient prior to embarking on this type of fixation.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_IV | Pages 440 - 441
1 Apr 2004
Graham J Turner P Johnson D
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Purpose To compare the patient’s experience of anterior cruciate ligament (ACL) reconstruction with previously validated outcome measures.

Methods Forty-five patients who had previously undergone ACL reconstruction performed by a single surgeon at least one year previously were assessed. A mean time of 33 months had elapsed between surgery and assessment. Each assessment included the Modified Lysholm Score, the Tegner Activity Score and the one-legged hop test (OHT). Patient’s subjective assessment included visual analogue scales (VAS) for pain, knee function, achievement of expectations and satisfaction. Correlation of all these items was performed using SPSS.

Results The mean Lysholm score was 90.3, with mean Tegner scores of 6.9 pre-injury, 5.2 currently and 6.3 desired. The mean OHT index was 0.92. The VAS scores (range 0 to 100) were 25 mm for pain, 79 mm for knee function and 77 mm for satisfaction. The VAS score (range −50 to 50) for expectations was 16 mm. Highly significant correlations were found between the Lysholm scores and all VAS scores; all VAS scores with each other; and the discrepancy between the current/desired Tegner scores and satisfaction. Significant correlations were found between age and achievement of expectations; the current Tegner score and achievement of expectations/satisfaction; and the discrepancy between the current/desired Tegner scores and achievement of expectations/time following surgery. There was a poor correlation between the OHT and the other variables in this post-operative population.

Conclusions Patient assessed measures of symptoms and satisfaction following ACL reconstruction correlate well with accepted outcome measures. A discrepancy between current and desired activity levels influence satisfaction following ACL reconstruction to a greater degree than actual activity levels. Patients should therefore be warned pre-operatively of a potential reduction in activity level post-operatively.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 162 - 162
1 Feb 2003
Johnson D Basso O
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The technique of arthroscopic decompression of patellar tendonitis was first undertaken in 1990. We report the 10 year experience of using this technique. Patients presenting with this condition were subjected to clinical, radiological and MRI assessment. The procedure was undertaken if the symptoms continued to be significant despite non-operative treatment. The procedure used a Dyonics shaver. The fat pad was elevated from the bare area of the patella to expose the non-articular inferior pole of the patella. The tendon fibres were then elevated from the anterior surface of the inferior pole, and the 5mm tip of the patella was excised taking particular care to ensure that the full AP thickness was removed.

Seventy three knees underwent surgery with a minimum of one year follow up, in four cases a simultaneous bilateral procedure was performed and in 11 cases previous surgery had been performed elsewhere. The average age was 33 years, 64 of the cases were male. The average duration of symptoms was 20 months and all patients had undergone non-operative treatment prior to the index procedure for an average duration of 10 months. The average duration of follow up was 49 months. All patients experienced a significant improvement in the clinical grade of symptoms and function with 95% of the 62 primary cases resulting in a good or excellent result. The average time to return to work and driving was 2 weeks and to sport was 9 weeks. In the 11 revision cases, 9 (81%) were improved and 6 (55%) had a good result.

The results of arthroscopic decompression for patellar tendonitis are superior to the other reported techniques. We conclude that excision of the inflammatory nodule and fat pad in this condition is unnecessary, other than to obtain visualisation of the inferior pole of the patella. The success of this procedure supports the suggestion that this condition is produced by a compression of the tendon and is best treated by decompression of the inferior patella pole.


Orthopaedic Proceedings
Vol. 85-B, Issue SUPP_II | Pages 167 - 167
1 Feb 2003
Johnson D
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We report our experience of four initial cases of mosaicplasty using large plugs in four cases and subsequently fourteen cases using the OATS technique and large grafts.

The average size of the articular lesion was 1.7 sq cm with a range of 1–3 sq cm. The average number of grafts used was 2.3 with a range of 1.5. The average size was 9 mm with a range of 4–10 mm. Including a poor result due to infection, pain was only found in three patients on activity (17%). The Tegner score and the IKDC score improved significantly. The initial four cases of mosaicplasty resulted in two cases having donor site pain and crepitus which required a lateral release. Using the OATS technique reconstructing the donor site no further cases of pain and crepitus occurred.

On MRI imaging, the recipient site was congruous, intact and appeared functional and only one patient demonstrated protuberance of the articular cartilage (1mm). Recipient site marrow oedema, fluid accumulation or kissing tibial signals were not significant features. The donor site articular cartilage was congruent in 5 patients and homogeneously isointense in 6 out of 7 patients.

We have modified the technique and used osteochondral transplantation to treat isolated articular cartilage defects of 1–3 sq cm in area, using a mini open technique and multiple large grafts, avoiding graft impaction and with reconstruction of the donor site. This technique has resulted in an 89% success rate at an average of 2.5 years post operatively. Eighty three per cent of patients were able to return to recreational sports. MRI follow up has shown no cause for concern and demonstrates incorporation of all the grafts. The success reported in this study is higher than reported elsewhere but this may reflect the use of the modified technique.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 257 - 257
1 Nov 2002
Parmar P Johnson D
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Purpose: To document healing of the anterior cruciate ligament

Introduction: Conventional wisdom holds that the anterior cruciate ligament (ACL) does not heal. In an athlete the ACL deficient knee is likely to be symptomatic and lead to functional instability. This has led to the belief that all ACL tears in the active athlete require reconstruction. Some ACL tears in recreational athletes are successfully treated conservatively with activity modification and bracing. A literature search was performed which found three articles on ACL healing. These articles felt that complete ACL tears could heal if patients were properly braced and rehabilitated.

Materials and Methods: At the Carleton University Sports Medicine Clinic we retrospectively reviewed ACL tears diagnosed by the Lachman, pivot shift, and KT-1000 arthrometer testing. We then examined those whose clinical exam became stable by the same three tests. The latest follow up exam was performed by the same examiner (P.P). At the follow up exam, knee function was evaluated with the expanded IKDC form.

Results: Nine patients were found to be asymptomatic and stable after an initial diagnosis of an ACL tear. In follow up the Lachman test had a good endpoint, the pivot shift was normal and the KT – 1000 manual max was less than 3mm. The IKDC results showed 3/9 were grade A, 5/9 were grade B and 1/9 was grade C.

The clinical implication: ACL tears should be treated initially conservatively since in a small percentage of patients, the ACL tear can heal.


The Journal of Bone & Joint Surgery British Volume
Vol. 76-B, Issue 6 | Pages 951 - 954
1 Nov 1994
Vangsness C Jorgenson S Watson T Johnson D

We dissected 105 cadaveric shoulders to study the origin of the tendon of the long head of biceps, and examined histologically the interrelationship between the tendon, the supraglenoid tubercle and the superior labrum of the glenoid. In all specimens approximately 50% of the biceps tendon arose directly from the superior glenoid labrum with the remainder attached to the supraglenoid tubercle. The main labral origin was from the posterior labrum in more than half of the specimens, and in a quarter this was the only labral attachment. On the basis of the biceps attachment to the anterior or posterior labrum, we distinguished four types of origin. These normal anatomical variations are significant for arthroscopic diagnosis and may help to explain the various patterns of injury seen in partial or complete detachment of the tendon, the labrum or both.


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 4 | Pages 656 - 658
1 Aug 1988
Johnson D

The viability of three incisions for knee arthroplasty were analysed by transcutaneous estimation of the skin oxygen tension. Wound viability was found to be significantly reduced following knee arthroplasty. The lateral wound edge is more hypoxic than the medial, but there were no significant differences between the three incisions.


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 4 | Pages 666 - 667
1 Aug 1988
Johnson D Donell S


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 2 | Pages 322 - 324
1 Mar 1988
Bannister G Auchincloss J Johnson D Newman J

Antibiotic levels in bone and fat were measured in patients undergoing knee replacement to determine the time that should elapse between intravenous injection and tourniquet inflation. The tissue levels increased progressively with time, and there was wide variation in absorption rate between patients and between the two cephalosporins assessed. Five minutes should probably be left between systemic injection and inflation of the tourniquet, though two minutes may be long enough for drugs which are rapidly absorbed.


The Journal of Bone & Joint Surgery British Volume
Vol. 69-B, Issue 5 | Pages 787 - 789
1 Nov 1987
Johnson D

A randomised prospective trial was undertaken of antibiotic prophylaxis given at various intervals before inflation of the tourniquet for arthroplasty of the knee. Cefuroxime assays of bone and subcutaneous fat from samples collected throughout the operation demonstrated that an interval of 10 minutes was necessary to obtain adequate prophylaxis. Improvement in the timing of antibiotic prophylaxis may result in a reduction in the incidence of infection.


The Journal of Bone & Joint Surgery British Volume
Vol. 68-B, Issue 5 | Pages 812 - 814
1 Nov 1986
Johnson D Houghton T Radford P

Early mobilisation after arthroplasty of the knee sometimes results in wound breakdown. The two commonly used incisions, the anterior midline and the medial parapatellar incisions, were compared in order to determine which had the best potential for wound healing. Study of the cleavage lines around the knee demonstrated that the medial parapatellar incision lies parallel to the lines, whilst the anterior midline incision lies perpendicular to them. In addition, the medial parapatellar wound was found to be subjected to significantly less tension during flexion; after arthroplasty it can be expected to heal faster and to be less liable to disruption during early mobilisation.


The Journal of Bone & Joint Surgery British Volume
Vol. 68-B, Issue 5 | Pages 698 - 701
1 Nov 1986
Johnson D Fergusson C

Atlanto-axial rotatory fixation is one of a spectrum of rotatory abnormalities of the atlanto-axial joint. Rotatory fixation without anterior displacement of the atlas (Type I) has been reported in only a few cases in which there has been a prolonged interval between injury and diagnosis. The majority of these cases eventually required cervical fusion for persistent deformity or instability. Two cases are presented in which this diagnosis was made early with the aid of rotated odontoid radiographs, tomography and computerised axial tomography. Treatment by a short period of halter traction achieved reduction and early return of function. The authors conclude that early recognition and treatment of this rare condition may prevent the subsequent deformity and instability for which cervical fusion has been required.


The Journal of Bone & Joint Surgery British Volume
Vol. 68-B, Issue 2 | Pages 289 - 291
1 Mar 1986
Johnson D Bannister G

In order to define the predisposing factors and outcome of infected arthroplasty of the knee, a retrospective analysis of a consecutive series of 471 knee arthroplasties was performed. There were 23 cases of superficial wound infection and 25 of deep infection. Superficial wound infection alone resulted in a painfree gait, with little limitation of movement. Rheumatoid arthritis, the use of constrained prostheses and the presence of a superficial wound infection, all predisposed to deep infection. Deep infection was eradicated by long-term antibiotics in only two patients in whom skin cover was successfully provided by a gastrocnemius musculocutaneous flap. Excision of a sinus track, wound debridement and exchange arthroplasty were universally unsuccessful. Arthrodesis, however, in 11 out of 12 cases, provided the painfree gait these patients desire.