SciELO - Scientific Electronic Library Online

 
vol.12 issue4Is there a role for prolonged post-operative antibiotic use in primary total hip arthroplasty in the African setting?Synovial haemangioma as a cause for atraumatic haemarthrosis of the knee - a case report author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Article

Indicators

Related links

  • On index processCited by Google
  • On index processSimilars in Google

Share


SA Orthopaedic Journal

On-line version ISSN 2309-8309
Print version ISSN 1681-150X

SA orthop. j. vol.12 n.4 Centurion Dec. 2013

 

KNEE

 

Focal full thickness articular cartilage lesions treated with an articular resurfacing prosthesis in the middle-aged

 

 

H HobbsI; N Ketse-MatiwaneII; W van der MerweIII, IV; M PosthumusV

IMBChB(UCT),  Dip PEC(SA),  FC Orth(SA),  MMed Orth (UCT)  The Sports Science Orthopaedic Clinic, Cape Town, South Africa
IIMSc UCT/MRC Research Unit for Exercise Science and Sports Medicine of the Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa
IIIMBChB(UOFS), Social Studies (Oxford), BMed Sport Hons(UCT) FCS(SA)Ortho The Sports Science Orthopaedic Clinic, Cape Town, South Africa
IVMBChB(UOFS), Social Studies (Oxford), BMed Sport Hons(UCT) FCS(SA)Ortho UCT/MRC Research Unit for Exercise Science and Sports Medicine of the Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa
VPhD, BSc(Hons) UCT/MRC Research Unit for Exercise Science and Sports Medicine of the Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

Correspondence

 

 


ABSTRACT

INTRODUCTION: Localised full thickness articular defects of the knee are common and disabling in the middle-aged. There are numerous treatment options for articular defects, the results of which are unpredictable in this age group. The purpose of this study was to evaluate a focal articular resurfacing prosthesis used in the treatment of these defects.
METHODS: A consecutive series of patients treated between 2005 and 2010 with a HemiCAP® resurfacing procedure were retrospectively reviewed. Follow-up scores of the KOOS, IKDC, SF-36 and patient satisfaction were obtained. Radiographic evaluation was also obtained.
RESULTS: Twenty-two patients met the inclusion criteria. Nineteen patients were followed-up 4.7 ± 5.9 years after surgery. Three patients had revision surgery and were not followed up. The patients were 44.7 ± 5.9 years old. The follow-up KOOS scores demonstrated comparable scores on the pain and activities of daily living sub-scales when compared to normative data; however, the sports (P<0.001) and quality of life (P=0.001) sub-scales scores were lower in the HemiCAP® patients when compared to normative data. Only the physical functioning sub-scale score of the SF-36, and not the other seven sub-scale scores, was lower (P=0.016) in the HemiCAP® patients when compared to normative data. General patient satisfaction revealed that 79% considered their result as very good or excellent.

CONCLUSION: HemiCAP® articular resurfacing is an effective treatment option for pain in the middle-aged patient with a focal articular cartilage defect in the knee.

Key words: HemiCAP®, knee cartilage lesion, resurfacing prosthesis, cartilage repair, arthroplasty


 

 

Introduction

The number of total knee arthroplasties continues to grow each year and as these increase in number, the number of revision total knee arthroplasties continues to increase substantially.1-3 Total or uni-compartmental knee arthro-plasty is also associated with an increased morbidity and revision rate in younger patients.4-6

Articular cartilage performs an important function in the homeostasis and functioning of joints.7-8 Focal full thickness articular lesions not only cause pain but also disturb this homeostasis and can lead to osteoarthritis if left untreated.7-5-11 The majority of these full thickness cartilage lesions are observed in patients over the age of 40 years.1112

A plethora of cartilage repair techniques is described in the literature,1314 with the most common form of surgical treatment undertaken being microfracture. The results with these surgical treatments are promising in young patients; however, the results are inconsistent and poorer in patients older than 40 years of age.15-18

The purpose of our study was to evaluate an articular resurfacing prosthesis (HemiCAP®, Arthrosurface Inc., Franklin, MA, USA) being used in middle-aged patients for focal full thickness articular cartilage lesions. This prosthesis forms a junction between biological healing and conventional arthroplasty. We evaluated our results and failures done in a single centre and report our results in the context of previously reported normative data19,20 as well as published data from previous multi-centred studies.21,22

 

Materials and methods

Participants

We retrospectively reviewed 30 patients who had undergone a HemiCAP® resurfacing procedure between 2005 and 2010. All patients had previously failed conservative and/or surgical management. All surgeries were performed by the same surgeon (author WvdM). All focal full thickness articular defects of the femoral condyle and patellofemoral joint were included in the review. All patients were screened according to the inclusion and exclusion criteria. The inclusion criteria were: all patients were >35 years old; had clinically significant baseline pain requiring surgical intervention; failed conservative and/or surgical management; good joint stability in the affected joint with a grade 1 Lachman or less with no pivot shift for anterior instability and no posterior translation of more than Grade 1; passive motion deficit measured as a lack of extension less than 10 degrees; normal or asymptomatic contralateral joint; and had signed the informed consent form to participate in the study. Exclusion criteria were as follows: patients with more than one grade IV (ICRS) articular surface defect on their femur as diagnosed intra-operatively resulting in inadequate implant coverage; severely obese with a BMI >35 kg/m2 at the time of surgery; impaired mental comprehension and literacy, including dementia, psychological impairment, and misuse of drugs or alcohol; displays varus or valgus joint malalignment greater than seven mechanical degrees in the affected limb; presents evidence of rheumatoid arthritis, gross joint destruction, infectious/crystal arthropathy; bone resorption visible on pre-operative roentgenogram or presents evidence of chronic instability or deficient soft tissues, support structures, vascular or muscular insufficiency; had a prior meniscal allograft, a failed osteochondral grafting with the presence of cysts, or partial joint replacement; significant damage (defined as worse than grade II changes) to the articular surface opposing the implant on the tibia as diagnosed intra-operatively; significant symptomatic damage to articular surfaces in other compartments within the affected joint as diagnosed pre- and intra-operatively or has infection, sepsis, and osteomyelitis or other active infections that may spread to the implant site.

Seven patients were lost to follow-up and were excluded from this series. One patient was excluded due to the fact she was diagnosed with rheumatoid arthritis at re-operation, when being revised from a HemiCAP® to a total knee arthroplasty.

Of the 22 patients who met the inclusion and exclusion criteria, 15 were male and seven female. All patients gave written informed consent. All the patients had swelling of the affected knee and moderate to severe pain at the time of presentation. All patients had a pre-operative MRI, which demonstrated an articular lesion with underlying bony changes.

Ethical approval was obtained and all patients signed a consent form to participate in the review.

Follow-up

All patients were invited to attend and were followed up for this case series between 4 and 6 years after surgery. All patients were assessed using the subjective Knee Injury and Osteoarthritis Outcome Score (KOOS),23 the subjective general health SF-3624 and patient satisfaction questionnaires. The KOOS score has been validated for the treatment of focal cartilage lesions.25 Data for the KOOS score and the SF-36 was compared to previously published normative data.19,20

In addition, the outcomes were also rated by an independent orthopaedic surgeon, following the International Knee Documentation Committee (IKDC) evaluation form.26 Radiographic assessment entailed comparing pre-operative radiographs to those obtained at the follow-up visit (AP and lateral knee X-rays weight bearing and a mechanical axis). These were then assessed using the Kellgren-Lawrence classification27 and Osteoarthritis Research Society International (AORSI) grading system28 to see if there were any changes.

Surgical technique and prosthetic device

A standard arthroscopy was performed and the lesion was evaluated in all included patients.

A small medial para-patellar arthrotomy was then undertaken. A guide pin was placed into the centre of the defect and the cancellous screw inserted. Mapping instruments were used to measure the surface curvature, upon which a matching surface reamer was used to prepare the bed. Sizing was then done using trials. The articular component was then inserted onto the fixation device and recessed slightly below the surrounding articular cartilage.

Statistics

The statistical analysis was performed using GraphPad Instat version 3 (GraphPad Software Inc., California, USA). Values were reported as a mean ± standard deviation (SD). To identify if the reported values were in range of the previously reported normative data for the validated scores reported, unpaired t-tests were performed between the means and standard deviations of the HemiCAP® patients and the means and standard deviations of the reported normative data. Significance was accepted when P<0.05.

 

Results

Patient characteristics

Of the 22 patients who met the inclusion criteria for the study, 15 were male and seven female. The average age of the patients was 44.7 ± 5.9 years (range 35-57). Patients were followed up 4.7 ±1.6 years (range 2-6) years after surgery. Fifteen of the lesions involved the right knee and seven the left. Sixteen had one or more prior cartilage procedure(s). Seven of the lesions were in the medial femoral condyle, 14 in the trochlea (of which five also involved the patella) and one was in the patella. Five of the patients had cartilage lesions elsewhere in the knee but were grade 2 or less. Six had partial medial meniscec-tomies (less than 50%) at the same procedure which could be a confounding factor. Of the seven lesions in the medial femoral condyle, six were resurfaced with a 20 mm prosthesis and one with a 15 mm prosthesis. Fourteen of the patellofemoral lesions, which were trochlea lesions, were resurfaced with a 20 mm prosthesis (five of these also had a patella resurfacing). One patient had a patella resurfacing only.

Three of the 22 patients had been revised since implantation and inclusion in this study. The three failures are discussed below. The outcomes at the current follow-up were recorded in the remaining 19 patients.

All patients reported that they would undergo the procedure again,
and that they would recommend it to family or friends

KOOS, SF-36 and patient satisfaction

The KOOS (Knee injury and Osteoarthritis Outcome Score) questionnaire Pain (P=0.346) and ADL (P=0.300) sub-scales were not different between the HemiCAP® patients and the normative data (Table I). Symptom (P=0.006), sport (P<0.001) and quality of life (P<0.001) KOOS sub-scales were significantly lower within the HemiCAP® patients when compared to the normative data.

 

 

The short form (SF)-36 questionnaires consisted of eight sub-scales (Table II). The physical functioning (PF), role-physical (RP), bodily pain (BP) and general health (GH) sub-scales are combined into the physical component summary (PCS). The vitality (VT), social functional (SF), role-emotional (RE) and mental health (MH) sub-scales are combined into the mental component summary (PCS). Of the eight sub-scales, only the PF (P=0.016) was significantly lower within the HemiCAP® patients, compared to previously reported normative data.20 The MCS was significantly higher (P=0.003) within the HemiCAP® patients, compared to previously reported normative data.20

 

 

General satisfaction by the patients with the procedure was rated as excellent by nine (47%), very good by six (32%), good by two (11%), and fair by two (11%). All patients reported that they would undergo the procedure again, and that they would recommend it to family or friends. Nine patients had no pain at all, ten had mild pain requiring occasional analgesia. No subjective data was obtained for the three revisions.

Surgeon-rated outcomes

These outcomes were rated by one of the co-authors who is an independent orthopaedic surgeon. At follow-up 13 (68%), four (21%) and two (11%) of the patients had normal, nearly normal and abnormal effusion, respectively, according to the IKDC evaluation.26 No patients had severely abnormal effusion at follow-up. In addition, 15 (79%), three (16%) and one (5%) of patients had normal, nearly normal and abnormal passive motion deficits, respectively. No patients had severely abnormal passive motion deficits. Ligament examination was normal for all 19 patients. Eleven of the 19 patients (58%) were classified as normal for all measurements of the IKDC knee evaluation.

The result in six patients was rated by the surgeon(s) as excellent (32%), very good in nine (47%), good in three (16%), and fair in one (5%). Radiographically there were no lucencies or cysts around the prosthesis and no subsidence of the prosthesis in any patient. There was no significant change in any of the radiographic findings or grades. One patient had disengagement of the articular component from the fixation device.

Revisions

Re-operations were done in three of the 22 patients (14%). The first was a patient who had a resurfacing of her trochlea and patella. She subsequently had another arthroscopy for pain where scar tissue was debrided. She was finally converted to a total knee arthroplasty for ongoing pain and swelling. The second patient had a medial femoral condyle HemiCAP® who had continued pain and swelling, and at arthroscopy had progression of the disease with cartilage involvement posterior to the prosthesis.

She was converted to uni-compartmental knee arthroplasty. The last patient also had a medial femoral condyle HemiCAP® and initially did extremely well, but had injured himself and sustained an MCL tear and an impaction fraction of the medial femoral condyle. He was treated conservatively for this injury but subsequently a year later the articular component disengaged from the fixation device (Figures 2A and 2B). He was converted to osteochondral plugs. At re-operation in all three patients, the HemiCAP® was easily removed and it was easy to convert to the chosen new treatment modality.

 

Discussion

The current case series documents the outcome of 22 patients, who had undergone a HemiCAP® focal isolated articular resurfacing procedure. At the current follow-up, 19 of the 22 patients were satisfied with the treatment and had successful alleviation of their pain.

Compared to normative data, the KOOS sub-scales for pain and activities of daily living were not significantly different.

Full thickness cartilage lesions are common and lead to symptomatic painful knees, the majority of which occur in the middle-aged (40-60 years).10,12 If left untreated, these defects are unlikely to heal and are a predisposing factor for the development of osteoarthritis.7,11,29 Conventional biological treatment measures include marrow stimulation techniques,