ArticlePDF Available

Early results of patellofemoral inlay resurfacing arthroplasty using the HemiCap Wave prosthesis

Authors:

Abstract

Background: Common surgical treatment options for isolated patellofemoral osteoarthritis include arthroscopic procedures, total knee replacement and patellofemoral replacement. The HemiCap Wave patellofemoral resurfacing prosthesis is a novel inlay design introduced in 2009 with scarce published data on its functional outcomes. We aim to prospectively evaluate early functional outcomes and complications, for patients undergoing a novel inlay resurfacing arthroplasty for isolated patellofemoral arthrosis in an independent centre. Methods: From 2010 to 2013, 16 consecutive patients underwent patellofemoral resurfacing procedures using HemiCap Wave (Arthrosurface Inc., Franklin, Massachusetts, USA) for anterior knee pain with confirmed radiologically and/or arthroscopically isolated severe patellofemoral arthrosis. Standardized surgical technique, as recommended by the implant manufacturer, was followed. Outcome measures included range of movement, functional knee scores (Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Short Form-36 (SF-36)), radiographic disease progression, revision rates and complications. Results: Eight men and eight women underwent patellofemoral HemiCap Wave resurfacing, with an average age of 63 years (range: 46-83). Average follow-up was 24.1 months (6-34). Overall, post-operative scores were excellent. There was a statistically significant improvement in the post-operative OKS, KOOS and SF-36 scores ( p < 0.01). One patient had radiological disease progression. One patient underwent revision for deep infection. Two other minor complications were observed and treated conservatively. Conclusions: The HemiCap Wave patellofemoral resurfacing prosthesis has excellent early results in terms of functional outcomes, radiological outcomes and low complication rates. At the very least, early results show that the HemiCap Wave is comparable to more established onlay prostheses. The HemiCap Wave thus provides a safe and effective surgical option in the treatment of isolated patellofemoral osteoarthritis in selected patients.
Article
Early results of patellofemoral inlay
resurfacing arthroplasty using the
HemiCap Wave prosthesis
Akash Patel, Zakir Haider, Amarjit Anand,
and Dominic Spicer
Abstract
Background: Common surgical treatment options for isolated patellofemoral osteoarthritis include arthroscopic
procedures, total knee replacement and patellofemoral replacement. The HemiCap Wave patellofemoral resurfacing
prosthesis is a novel inlay design introduced in 2009 with scarce published data on its functional outcomes. We aim to
prospectively evaluate early functional outcomes and complications, for patients undergoing a novel inlay resurfacing
arthroplasty for isolated patellofemoral arthrosis in an independent centre. Methods: From 2010 to 2013, 16 consecutive
patients underwent patellofemoral resurfacing procedures using HemiCap Wave (Arthrosurface Inc., Franklin, Massa-
chusetts, USA) for anterior knee pain with confirmed radiologically and/or arthroscopically isolated severe patellofemoral
arthrosis. Standardized surgical technique, as recommended by the implant manufacturer, was followed. Outcome
measures included range of movement, functional knee scores (Oxford Knee Score (OKS), Knee Injury and Osteoarthritis
Outcome Score (KOOS) and Short Form-36 (SF-36)), radiographic disease progression, revision rates and complications.
Results: Eight men and eight women underwent patellofemoral HemiCap Waveresurfacing, with an average age of 63 years
(range: 46–83). Average follow-up was 24.1 months (6–34). Overall, post-operative scores were excellent. There was a
statistically significant improvement in the post-operative OKS, KOOS and SF-36 scores (p<0.01).Onepatienthad
radiological disease progression. One patient underwent revision for deep infection. Two other minor complications were
observed and treated conservatively. Conclusions: The HemiCap Wave patellofemoral resurfacing prosthesis has
excellent early results in terms of functional outcomes, radiological outcomes and low complication rates. At the very least,
early results show that the HemiCap Wave is comparable to more established onlay prostheses. The HemiCap Wave thus
provides a safe and effective surgical option in the treatment of isolated patellofemoral osteoarthritis in selected patients.
Keywords
arthroplasty, HemiCap Wave, inlay, patellofemoral, resurfacing
Introduction
Patellofemoral arthritis is a significant cause of morbidity
treated by orthopaedic surgeons. It is an increasingly
important issue, now recognized to be more common than
previously thought.
1
Reports suggest that isolated sympto-
matic patellofemoral osteoarthritis occurs between 8%and
13%in patients over the age of 60 years.
2,3
Risk factors for developing patellofemoral osteoarthritis
include trauma, recurrent dislocations, patellofemoral mis-
alignment and trochlear dysplasia.
4
However, often there is
no obvious cause in many patients.
Initial treatment options are conservative and include
weight loss, taping, bracing, physiotherapy, activity mod-
ification and anti-inflammatory medication. Surgical treat-
ment options include procedures to correct patellofemoral
Department of Trauma and Orthopaedic, St Mary’s Hospital, Imperial
College Healthcare NHS Trust, London, UK
Corresponding author:
Zakir Haider, Department of Trauma and Orthopaedic, St Mary’s Hospital,
Imperial College Healthcare NHS Trust, Paddington, London W2 1NY, UK.
Email: zakirhaider10@gmail.com
Journal of Orthopaedic Surgery
25(1) 1–5
ªJournal of Orthopaedic Surgery 2017
Reprints and permissions:
sagepub.co.uk/journalsPermissions.nav
DOI: 10.1177/2309499017692705
journals.sagepub.com/home/osj
Journal of
Or thopaedic
Surger
y
pathomechanics, arthroscopy (debridement, microfracture
and autologous chondrocyte implantation), total knee
replacement (TKR), patellectomy and patellofemoral
replacement.
Indications for isolated patellofemoral arthroplasty
(PFA) include the following
5
:
1. failure of conservative treatment,
2. absence of tibiofemoral arthritis,
3. normal patella alignment/tracking, and
4. intact/stable menisci and ligaments.
Patellofemoral replacement has been described since
1955, when McKeever performed patellar resurfacing in
40 knees, with initial designs yielding less than satisfactory
results.
6
Patellofemoral joint resurfacing gained further
interest in the 1970s with publication of the results of the
first generation of prostheses.
7
In 1974, Bechtol introduced
both patellar and femoral resurfacing components designed
to be used either in isolation or in conjunction with a uni-
condylar or TKR.
8
Results with first-generation prosthesis
have been variable, with significant improvements in
newer designs.
4,9
The high failure rates reported with some
of the early onlay designs, such as the Lubinus,
10
resulted
in many surgeons preferring TKR for isolated patellofe-
moral arthritis.
11
The HemiCap Wave patellofemoral prosthesis is an
inlay design, intended for patients with isolated patellofe-
moral arthritis and normal patella tracking. This prosthesis
was only introduced in 2009 and little data has been pub-
lished on its functional outcomes. HemiCap Wave is the
only true complete inlay type patellofemoral replacement
(Figure 1). The prosthesis aims to maintain native joint
biomechanics by intraoperative three-dimensional joint
mapping, and the use of contoured implants enables a more
anatomical resurfacing.
12
A biomechanical study assessing
patellofemoral kinematics of the inlay focal HemiCap res-
urfacing demonstrated anatomic re-approximation of the
patellofemoral surface and knee contact pressures.
13
One study evaluated clinical outcomes and sports-
related results in a cohort of 27 patients aged 42 years
(+13) who had undergone HemiCap Wave resurfacing.
Results revealed statistically significant improvements
post-operatively in Western Ontario and McMaster Univer-
sities Osteoarthritis Index (WOMAC), pain visual analogue
scale (VAS) and subjective International Knee Documen-
tation committee (IKDC) scores.
12
Verma et al.
14
published a case series assessing a similar
prosthesis, the focal HemiCap resurfacing. This is a much
smaller inlay design and is used for isolated patellofemoral
focal defects. Forty-three procedures were undertaken and
patients were followed up for a mean of 9 months (range:
1–20). Overall, good post-operative functional results and
surgeon satisfaction were demonstrated.
The aim of this study is to present our early results on
functional outcomes and complications for patients under-
going HemiCap Wave PFA for isolated patellofemoral
arthrosis.
Methods
Sixteen patients were included in this study who underwent
patellofemoral resurfacing using HemiCap Wave (Arthro-
surface Inc., Franklin, Massachusetts, USA) for isolated
patellofemoral arthrosis from March 2010 to July 2013.
No children or vulnerable adult groups were included.
Indications for patellofemoral replacement included
severe isolated patellofemoral osteoarthritis characterized
by anterior knee pain and osteoarthritic changes on radio-
graphs only in the patellofemoral joint with normal tibio-
femoral compartments and normal patella alignment.
Diagnosis of isolated patellofemoral osteoarthritis was
based on clinical, radiological and, where available, arthro-
scopic findings (some patients previously underwent
arthroscopy to assess and debride the patellofemoral joint
(PFJ), specifically any loose patellofemoral chondral
flaps). Patients with any degree of fixed flexion deformities
were excluded.
All patients had preoperative weight-bearing standard
anteroposterior, lateral and patella skyline radiographs.
MRI scanning was also undertaken to confirm normal tibio-
femoral cartilage surfaces and assess PFJ. Surgery was
performed in consecutive patients by the senior author or
under his direct supervision.
Post-operatively, patients were allowed to weight bear
as tolerated and followed a standardized physiotherapy
protocol.
Primary functional outcomes were measured using the
Oxford Knee Score (OKS),
15
Knee Injury and Osteoarthri-
tis Outcome Score (KOOS)
16
and Short Form-36 (SF-36)
17
recorded pre- and post-operatively. The OKS has been used
in multiple studies assessing other PFA designs
11,18,19
and
is a validated patient-reported functional outcome measure.
Use of the OKS allows direct comparison of the Hemi-
Cap Wave resurfacing with other patellofemoral joint
Figure 1. HemiCap Wave (trochlear and patella components).
2Journal of Orthopaedic Surgery 25(1)
replacements, such as the Avon prosthesis (Stryker, How-
medica Osteonics, Allendale, New Jersey, USA). Both the
KOOS and SF-36 are validated and have been highly rec-
ommended in a study by Paxton and Fithian
20
assessing
outcome instruments for PFA.
Secondary outcome measures included range of motion,
radiological parameters (progression of tibiofemoral
osteoarthritis as per Kellgren and Lawrence/Ahlback grad-
ing) as well as complications and reoperations. Data was
prospectively collected using a standardized proforma from
patient notes and Picture Archiving and Collection System
(Philips Medical Systems, Sectra Imtec AB, Sweden).
Patients were routinely followed up in clinic, and post-
operative radiographs were taken. They were reviewed by
the senior surgeon and first author at 6 weeks, 3 months,
6 months and yearly from date of surgery. Range of motion
was measured using a goniometer by the first author only to
aid reliability of measurements. Data was analysed using
SPSS (IBM-SPSS, New York, USA). To test for statistical
significance, paired t-test was used with significance level
set as p< 0.05.
Ethical considerations
This study was conducted as a service evaluation. No fund-
ing/sponsorship from the implant company was obtained to
aid this study. As part of the clinical team caring for these
patients, no consent was required to assess patient notes.
Data was held in accordance with the Data Protection Act.
Approval for this study was obtained from the Biomedical
Research Ethics Sub-committee and regulatory compliance
department at Imperial College London.
Results
Sixteen patients underwent patellofemoral resurfacing
using HemiCap Wave for isolated severe osteoarthritis.
The cohort included eight men and eight women with an
average age of 63 years (46–83) and Body Mass Index 27.2
(22.5–30) at time of surgery. The mean follow-up was 24.1
months (6–34), and no patients were lost to follow-up.
Six patients had previous knee surgery. Of these, five
patients had arthroscopies with debridement of patellofe-
moral chondral defects. Two of these five patients also had
partial meniscectomies. One patient had tibial tubercle
transfer and autologous matrix-induced chondrogenesis.
At operation, all patients had severe patellofemoral
osteoarthritis. Only one patient had grade 1 (Outerbridge)
osteoarthritis in the medial compartment. There were no
intraoperative complications.
Statistically significant improvements were found in
mean scores for the OKS and KOOS post-operatively
(p< 0.01). Although there was significant improvement
in the physical SF-36 post-procedure (p< 0.01), improve-
ments in the mental SF-36 and increase in knee flexion of
5post-procedure were found to be statistically insignifi-
cant (Table 1).
Three patients had post-operative complications. One
patient developed keloid scarring which was asymptomatic
and did not require treatment. One patient developed synovi-
tis which settled with anti-inflammatory medication. A third
patient had continuing pain and swelling post-operatively. He
had persistently raised inflammatory markers with suspected
deep infection. He subsequently underwent a joint aspiration
which was negative with eventual revision to a TKR 18
months after initial surgery for infection.
At follow-up, only one patient had progression of
osteoarthritis. She was 23 months post-surgery with grade
2 (Kellgren and Lawrence) and grade 2 (Ahlback) medial
tibiofemoral compartment osteoarthritis. However, she was
asymptomatic and did not require further intervention.
Discussion
Isolated patellofemoral arthritis is a significant cause of mor-
bidity, which can be treated surgically with PFA. This study
assessed outcomes of the HemiCap Wave patellofemoral
replacement for patients with isolated patellofemoral
osteoarthritis. We assessed 16 patients pre- and post-
operatively and found a statistically significant improvement
in their KOOS, OKS and SF-36 (physical) scores at an aver-
age of 24.1 months follow-up (p< 0.01). Only two minor
complications were observed, neither of which required sur-
gical intervention. These results suggest good short-term
functional outcomes with low complication rates.
To the best of our knowledge, only two studies to date
have evaluated functional outcomes of the HemiCap
Wave.
12,21
Twenty-seven patients were included by Imhoff
et al.
12
with an average age of 42 and were followed up
over 24 months. The patients were split into two groups:
those who underwent isolated patellofemoral inlay
Table 1. Comparison of pre- and post-operative functional outcome measures.
Outcome measure Mean preoperative value Mean post-operative value Statistical significance
Range of movement (knee) 0–1150–120Nil
OKS 19 (2–30) 35 (10–44) p< 0.01
KOOS 39 (5–64) 55 (33–85) p< 0.01
SF-36 (physical) 32 (19–40) 53 (19–70) p< 0.01
SF-36 (mental) 42 (18–55) 45 (20–62) Nil
OKS: Oxford Knee Score; KOOS: Knee Injury and Osteoarthritis Outcome Score; SF: Short Form-36.
Patel et al. 3
surfacing and those who required inlay surfacing and con-
comitant procedures to address patellofemoral instability/
malalignment and tibiofemoral malalignment. Authors
found a statistically significant reduction in total WOMAC,
IKDC and pain VAS scores as well as sports-related Tegner
Score and found more patients partaking in sports post-
operatively. Two patients required reoperation for compo-
nent disassembly and graft slippage post-concomitant med-
ial patellofemoral ligament reconstruction.
Our study is different in terms of the considerably
younger cohort of patients used by Imhoff et al.
12
and some
patients requiring concomitant procedures at time of resur-
facing as well different functional outcomes measures
used. Another paper, published by the implant manufac-
turer (Arthrosurface Press) commentated on a brief inves-
tigation of 22 patients with mean age of 43 years who
underwent HemiCap Wave resurfacing. Follow-up was for
15 months, and preliminary results revealed clinical
improvement in the Kujala and IDKC scores.
22
One study compared an onlay design prosthesis (Jour-
ney PFJ, Smith & Nephew, UK) to the inlay HemiCap
Wave in 15 patients. They found statistically significant
improvements in WOMAC, Lysholm and pain VAS scores
post-operatively with both prostheses. No significant dif-
ference was found in clinical outcome scores between
onlay versus inlay designs. However, in the onlay group,
53%of patients exhibited progression in osteoarthritis
compared to the inlay group (p¼0.009).
Statistics from the 12th annual report (2015) from the
United Kingdom National Joint Registry (NJR) reveal that
PFA makes 1.3%of all primary knee replacements. The
median age for patients undergoing PFA is 59 years com-
pared to 70 years for TKR; hence, survivorship of prosthesis
is all the more important. Between 2003 and 2014, the Avon
prosthesis has been most popular forming 44.8%of all PFA
performed (4457 out of 9945 PFA procedures) followed by
the Femoro Patella Vialli (Wright Medical, UK) with 1433
procedures. In total, there are five PFA prostheses, which
data is provided for by the NJR; all of which have an onlay
design. The Avon prosthesis, however, most closely resem-
bles the HemiCap Wave patellofemoral resurfacing in
terms of engineering. It is the only patellofemoral pros-
thesis with more than 1000 cases having longer than a
5-year follow-up. In terms of survivorship, only three
prostheses had more than a thousand cases available, and
the cumulative percentage probability for a first revision
at 5 years was between 7.66%for Avon and 12.39%for
Journey PFJ (Smith & Nephew). The most common indi-
cation for revision was progression of osteoarthritis.
These results show continued use of traditional onlay
designs however, as more data is collected on the newer
generation of inlay design prostheses such as the Hemi-
Cap Wave; it may reveal a better alternative.
Advantages of inlay resurfacing include preservation
of native geometry with minimal bone loss and soft
tissue disruption, thus causing minimal disruption to
natural joint biomechanics and reducing the risk of joint
overstuffing. The multiple convexities of the HemiCap
Wave assure anatomic fit.
12
Weaknesses of this study include a small sample size
with non-significant mental SF-36 score and range of
motion outcome likely due to this reason. Strengths include
the prospective design with complete pre- and post-
operative scores with no loss to follow-up. This study also
benefits from being a consecutive series performed or
supervised by a single surgeon in an independent centre,
reducing confounders, with strict inclusion criteria.
We recommend further research to be performed using a
randomized controlled study, larger homogenous patient
cohort with longer follow-up. Additionally, future studies
should use similar functional outcome measures to allow
study results to be compared.
Conclusion
In conclusion, little data exists on functional outcomes fol-
lowing use of the HemiCap Wave prosthesis. Our results
demonstrate that the HemiCap Wave has excellent early
results, in terms of functional outcomes, radiological out-
comes and low complication rates. At the very least, early
results show that the HemiCap Wave is comparable to more
established onlay prostheses. The HemiCap Wave thus pro-
vides a safe and effective surgical option in the treatment of
isolated patellofemoral osteoarthritis in selected patients.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with
respect to the research, authorship, and/or publication of this
article.
Funding
The author(s) received no financial support for the research,
authorship, and/or publication of this article.
References
1. Gao X, Xu Z, He R, et al. A preliminary report of patellofe-
moral arthroplasty in isolated patellofemoral arthritis. Chin
Med J 2010; 123(21): 3020–3023.
2. Davies A, Vincent A, Shepstone L, et al. The radiologic pre-
valence of patellofemoral osteoarthritis. Clin Orthop 2002;
402: 206–212.
3. McAlindon T, Snow S, Cooper C, et al. Radiographic patterns
of osteoarthritis of the knee joint in the community: the
importance of the patellofemoral joint. Ann Rheum Dis
1992; 51: 844–849.
4. Lonner J. Patellofemoral arthroplasty. JAmAcadOrthop
Surg 2007; 15: 495–506.
5. Cannon A, Stolley M, Wolf B, et al. Patellofemoral resurfa-
cing arthroplasty: literature review and description of a novel
technique. Iowa Orthop J 2008; 28: 42–48.
6. McKeever D. Patellar prosthesis. J Bone Joint Surg (Am)
1955; 37–A: 1074–1084.
4Journal of Orthopaedic Surgery 25(1)
7. Bazina M, Fox J, Del Pizzio W, et al. Patellofemoral replace-
ment. Clin Orthop 1979; 144: 98–102.
8. Krajca-Radcliffe J and Coker T. Patellofemoral arthroplasty:
A 2- to 18-year follow-up study. Clin Orthop Rel Res 1996;
330: 143–151.
9. Leadbetter W, Ragland P and Mont M. The appropriate use of
patellofemoral arthroplasty: an analysis of reported indica-
tions, contraindications, and failures. Clin Orthop Rel Res.
2005; 436: 91–99.
10. Tauro B, Ackroyd C, Newman J, et al. The Lubinus patello-
femoral arthroplasty: a five- to ten-year prospective study. J
Bone Joint Surg (Br) 2001; 83–B: 696–701.
11. Starks I, Roberts S and White S. The Avon patellofemoral
joint replacement: independent assessment of early functional
outcomes. J Bone Joint Surg (Br) 2009; 91–B: 1579–1582.
12. Imhoff AB, Feucht MJ, Meidinger G, et al. Prospective
evaluation of anatomic patellofemoral inlay resurfacing:
clinical, radiographic, and sports-related results after 24
months. Knee Surg Sports Traumatol Arthrosc 2015;
23(5): 1299–1307.
13. Provencher M, Ghodadra N, Verma N, et al. Patellofemoral
kinematics after limited resurfacing of the trochlea. J Knee
Surg. 2009; 22: 310–316.
14. Verma N, Geissler W, Merwe W, et al. Congruent patellofemoral
resurfacing, part 1: objective multicentre assessment, surgical
technique and case report.Franklin,Massachusetts,USA:
Arthrosurface Press, 2008.
15. Dawson J, Fitzpatrick R, Murray D, et al. Questionnaire on
the perceptions of patients about total knee replacement.
J Bone Joint Surg (Br) 1998; 80–B: 63–69.
16. Roos E, Roos H, Lohmander L, et al. Knee injury and osteoar-
thritis outcome score (KOOS) – development of a self-
administered outcome measures. J Orthop Sports Phys Ther
1998; 28(2): 88–96.
17. Ware J. SF-36 health survey update. Spine. 2000; 25(24):
3130–3139.
18. Ackroyd C, Newman J, Evans R, et al. The Avon patellofe-
moral arthroplasty: five-year survivorship and functional
results. J Bone Joint Surg (Br) 2007; 89–B: 310–315.
19. Odumenya M, Costa M, Parsons N, et al. The Avon
patellofemoral joint replacement: five year results from
an independent centre. J Bone Joint Surg (Br) 2010; 92–
B: 56–60.
20. Paxton E and Fithian D. Outcome instruments for patellofe-
moral arthroplasty. Clin Orthop 2005; 436: 66–70.
21. Feucht M, Cotic M, Beitzel K, et al. A matched-pair compar-
ison of inlay and onlay trochlear designs for patellofemoral
arthroplasty: no differences in clinical outcomes but less pro-
gression of osteoarthritis with inlay designs. Knee Surg
Sports Traumatol Arthrosc 2015; 1–8.
22. Imhoff AB, Schepsis A, Scho¨ttle PB., et al. Review of con-
gruent patellofemoral inlay arthroplasty. From focal to total
patellofemoral surface reconstruction. Franklin, Massachu-
setts, USA: Arthrosurface Press, 2014.
Patel et al. 5
... In the case of ROM, 12 studies were identified for data extraction. The majority of the studies reported an increase in the postoperative ROM when compared to preoperative values [1,12,19,24,27,35,38,43,50]. Contrary to the majority, Al-Hadithy et al. reported no change in ROM, when comparing preoperative values to 12-months followup ones [4]. ...
... Tegner score was reported by five studies [7,12,23,30,40]. Furthermore, Kujala score [42,48,50], Lysholm score [16,42,50], KOOS [1,12,38], SF-12 and SF-36 [1,19,38] UCLA [12,30], MKS [19,43], HKS [3], IKS [10], IKDC [23], AKP [10] and HSS-PF [50] were also presented. A small difference in Lysholm score values between inlay and onlay designs has been reported at a median follow-up period of 25.5 months (range not given), with the inlay group scoring slightly higher (66 ± 11 vs. 57 ± 22) [16]. ...
... Tegner score was reported by five studies [7,12,23,30,40]. Furthermore, Kujala score [42,48,50], Lysholm score [16,42,50], KOOS [1,12,38], SF-12 and SF-36 [1,19,38] UCLA [12,30], MKS [19,43], HKS [3], IKS [10], IKDC [23], AKP [10] and HSS-PF [50] were also presented. A small difference in Lysholm score values between inlay and onlay designs has been reported at a median follow-up period of 25.5 months (range not given), with the inlay group scoring slightly higher (66 ± 11 vs. 57 ± 22) [16]. ...
Article
Full-text available
Purpose: The aim of this study was to report the clinical and functional outcomes, complication rates, implant survivorship and the progression of tibiofemoral osteoarthritis (OA), after new inlay or onlay patellofemoral arthroplasty (PFA), for isolated patellofemoral OA. Comparison of different implant types and models, where it was possible, also represented one of the objectives. Methods: A systematic literature search following PRISMA guidelines was conducted on PubMed, Scopus, Embase and Cochrane databases, to identify possible relevant studies, published from the inception of these databases until 11.11.2022. Randomized control trials (RCTs), case series, case control studies and cohort studies, written in English or German, and published in peer-reviewed journals after 2010, were included. Not original studies, case reports, simulation studies, systematic reviews, or studies that included patients who underwent TKA or unicompartmental arthroplasty (UKA) of the medial or lateral compartment of the knee, were excluded. Additionally, only articles that assessed functional and/or clinical outcomes, patient-reported outcomes (PROMs), radiographic progression of OA, complication rates, implant survival rates, pain, as well as conversion to TKA rates in patients treated with PFA, using inlay or onlay trochlea designs, were included. For quality assessment, the Methodological Index for Non-Randomized Studies (MINORS) for non-comparative and comparative clinical intervention studies was used. Results: The literature search identified 404 articles. 29 of them met all the inclusion criteria following the selection process. Median MINORS for non-comparative studies value was 12.5 (range 11-14), and for comparative studies 20.1 (range 17-24). In terms of clinical and functional outcomes, no difference between onlay and inlay PFA has been described. Both designs yielded satisfactory results at short, medium and long-term follow-ups. Both designs improved pain postoperatively and no difference between them in terms of postoperative VAS has been noted, although the onlay groups presented a higher preoperative VAS. When comparing the inlay to onlay trochlea designs, the inlay group displayed a lower progression of OA rate. Conclusion: There is no difference in functional or clinical outcomes after PFA between the new inlay and the onlay designs, with both presenting an improvement in most of the scores that were used. A higher rate of OA progression was observed in the onlay design group. Level of evidence: III.
... Prensip olarak subkondral kemiğin şeklini değiştirmeden aşınmış kıkırdağı değiştirirler. [10,27] Değişken offsetlere ve eğrilik yarıçaplarına sahip farklı implant tipleri mevcuttur. Inlay tasarımlı bir protezin potansiyel avantajları arasında daha az kemik çıkarılması, artan intrinsik implant stabilitesi, değiştirilmemiş yumuşak doku gerilimi ile ekstansör mekanizma ve patellofemoral eklemin aşırı doldurulması riskinin daha az olması sayılabilir. ...
... [21] Hasta seçimine azami dikkat edilerek kullanılması önerilen ve artroskopik eşlikli de yerleştirilebilen inlay tasarımlara ait orta ve erken dönemde başarılı sonuçlar bildiren çalışmalar mevcuttur. [27] Artroskopik uygulama ile diz içi patolojiler daha iyi gözlemlenebilmekte ve aynı zamanda lateral gevşetme de yapılabilmektedir. [32] Laursen ve ark.'nın çalışmasında da yüzey protezi uygulanan hastalarda erken dönemde fonksiyon skoru ve ortalama ağrı skorlarının önemli ölçüde düzeldiği gösterilmiştir. ...
... 9 The new inlay design better maintains the natural biomechanics of the joint and allows personalized and anatomic trochlear resurfacing, reducing complications, improving stability, preserving soft tissue tension, and minimizing overstuffing. [9][10][11][12][13][14] After meticulous patient selection, the crux of PFA success lies in the accurate choice of prosthesis and the precise execution of surgical procedures, especially in cases where trochlear dysplasia is present. 1 In this Technical Note, we provide insights on the proper technique for proper inlay implant positioning and describe the intraoperative parameters to guide the surgeon in selecting and positioning standard versus dysplastic inlay implants. ...
Article
Full-text available
Patellofemoral arthroplasty (PFA) has emerged as an alternative bone-preserving surgical option for treating isolated symptomatic patellofemoral osteoarthritis that better replicates the natural knee kinematics compared with total knee arthroplasty. Achieving successful outcomes in PFA relies on meticulous patient selection, proper surgical technique, and appropriate implant choice and placement. Recent advancements in inlay trochlea implants, allowing for customized and anatomic joint line reconstruction with less bone resection, have demonstrated significant improvements in functional outcome scores and pain relief. This Technical Note aims to provide insights into the surgical technique of PFA with inlay implants, highlighting key considerations and potential challenges. It also assists surgeons in making informed decisions regarding the choice between standard and dysplastic inlay implants, while suggesting concurrent procedures to optimize tracking and overall outcomes.
... However, in a later article, the same author reported good clinical and radiographic outcomes for patients who did not require revisions, with no failures observed after 5 years [10]. The conversion rate was lower overall in cohort studies with shorter observational periods, although these studies had small samples [14,16]. Among a retrospective cohort of 20 I-PFAs, 11 with an elevated Insall-Salvati index and increased patellofemoral congruence angle showed a satisfactory initial result, although the patients subsequently presented with recurrent pain and a clunking sound [1]. ...
Article
Full-text available
We present the case of a 35-year-old patient who underwent inlay patellofemoral arthroplasty (I-PFA) followed by secondary patellar realignment surgery and inlay-to-inlay revision. Revision was performed because of ongoing pain, crepitation, and lateral subluxation of the patella. The original patella component (30-mm button) was replaced with a 35-mm dome, while the Hemi-Cap Wave® (7 × 5 mm) I-PFA was replaced with the Hemi-Cap Kahuna® (10 × 5 mm). At the 1-year follow-up, the clinical symptoms were resolved. Radiography revealed an aligned patellofemoral compartment with no signs of loosening. Inlay-to-inlay PFA revision appears to be a reasonable alternative to total knee arthroplasty and conversion to onlay-PFA (O-PFA) for symptomatic patients with primary I-PFA failure. Thorough patellofemoral evaluation and appropriate patient and implant selection are key for successful I-PFA, while additional procedures for patellar realignment may also be required for satisfactory long-term outcomes.
... 19 Patel A et al. concluyeron su estudio con excelentes resultados funcionales y radiológicos en un seguimiento de dos años. 20 De la misma manera, Cartier y cols. realizaron seguimientos con un promedio de cuatro años en los que resaltaron resultados favorables en todos los pacientes que estudiaron con mejoría funcional y diminución del dolor. ...
Article
Full-text available
Antecedentes: La articulación patelofemoral (PF) es un sistema biomecánico susceptible a desgaste acelerado, afecta a 25% de las mujeres. Actualmente, el tratamiento de la osteoartrosis patelofemoral (OAPF) ha resurgido gracias a la creación de sistemas anatómicos y biomecánicamente adecuados, con indicaciones precisas, estadios más tempranos y con mejor resultado funcional. Material y métodos: Se analizó una cohorte de 24 pacientes durante el período de 2010 a 2012, tratados con prótesis de resuperficialización patelofemoral (PPF) HemiCap Patelofemoral Resurf (Franklin MA, EUA), colocadas por dos cirujanos. Se evaluaron los pacientes prequirúrgicos y a los dos, cuatro, seis, 12, 18, 24 meses postquirúrgicos con la escala Knee Society Score (KSS). Resultados: Se incluyeron 24 pacientes con seguimiento de dos años en promedio. En 87.5% fueron mujeres, edad promedio de 62 años (45-80 años); una media de 29.5 de índice de masa corporal (IMC), la lateralidad derecha predominó en 54%. Se observó una mejoría en los resultados de la escala KSS: en el aspecto clínico hubo una mejoría de 35.2% y en la escala funcional de 41.62%. Sólo dos pacientes fueron reintervenidos por complicaciones de limitación funcional, uno de ellos tratado con manipulación bajo anestesia y el otro con liberación artroscópica de adherencias. Conclusión: La PPF es una opción como tratamiento de AOPF aislada, pues la tasa de supervivencia a dos años es buena, proporciona alivio del dolor y mejoría en funcionalidad de la rodilla; sin embargo, se requerirá mayor tiempo de seguimiento para evaluar el resultado final de este implante.
... Our electronic searches returned 37abstracts we excluded three Biomechanical / Clinical Laboratory study (40)(41)(42), and one cadaveric study (20), six animal studies (43-48), five instructional/systematic reviews (49)(50)(51)(52)(53), seven partial resurfacing of the PFJ (29, [54][55][56][57][58][59], and one study that has no functional outcome measures (60). Furthermore, eight studies (27,30,31,(33)(34)(35)(36)(37) were included in the systematic review but were excluded from the meta-analysis because they didn't use the KOOS score as an outcome measure. ...
Article
Knee osteochondral defects are a common problem among people, especially young and active patients. So effective joint preserving surgeries is essential to prevent or even delay the onset of osteoarthritis for these group of patients. This study aims to critically appraise and evaluate the evidence for the results and effectiveness of femoral condyle resurfacing (HemiCAP/ UniCAP) in treatment of patients with focal femoral condyle cartilage defect. Using the search terms : HemiCAP, UniCAP, Episurf, focal, femoral, condyle, inlay and resur-facing, we reviewed the PubMed and EMBASE and the Cochrane Database of Systematic Reviews (CDSR) to find any articles published up to March 2020. The short term follow-up of the HemiCAP shows (6.74 %) revision rate. However, 29.13 % loss of follow up let us consider these results with caution especially if the revision rate progressively increased with time to 19.3 % in 5-7 years with no enough evidence for the long term results except the data from the Australian Joint Registry 2018, where the cumulative revision rate was 40.6 % (33.5, 48.4) at ten years. The UniCAP that used for defect more than 4 cm 2 has a high revision rate (53.66 %) which is considered unacceptable revision rate in com-parison to another similar prosthesis such as Uni-Knee Arthroplasty (UKA). The evidence from published studies and our meta- analysis suggests that partial resurfacing of the femoral condyle (HemiCAP) doesn't support its usage as a tool to treat the focal cartilage defect in middle- aged patients. The UniCAP as femoral condyle resurfacing has very high revision rate at 5-7 years (53.66 %) which make us recommend against its usage.
Article
Mini-metal implants are indicated for treatment of symptomatic focal chondral or osteochondral defects in patients considered too old for biological reconstruction or too young with limited cartilage defects for knee arthroplasty. Precise surgical techniques are required to ensure optimal positioning with recession below the articular cartilage surface. Partial resurfacing for femoral or trochlea surfaces using the HemiCAP and UniCAP implants or the Episealer system has shown good short-term outcomes for middle-aged patients. In some series however, quantification of tibial articular surface wear was not reported making interpretation of the clinical benefit difficult. When successful, clinical function is high and results appear durable. Favourable outcomes are seen with well-defined indications of: isolated defect, healthy opposing articular cartilage and >50% volume meniscus. Indications also include patients with failed previous cartilage repair and those facing revision articular cartilage repair. Extended indications may include multiple lesions and requirement for concomitant osteotomy or ligament reconstruction.
Article
Background Patients with recalcitrant anterior knee pain and isolated patellofemoral osteoarthritis (PFOA) may benefit from patellofemoral arthroplasty. Arthroplasty with an inlay implant may be beneficial given recreation of native biomechanics and potentially avoiding anterior overstuffing. Indications Patellofemoral arthroplasty is indicated in patients with anterior knee pain from isolated PFOA in patients with neutral alignment and intact menisci and ligaments. To highlight these indications, we present a 32-year-old female with severe anterior knee pain from PFOA, not resolved by conservative measures. Preoperative imaging demonstrated full-thickness chondral loss of the lateral patellar facet and trochlea, with neutral alignment and no significant trochlear dysplasia. Technique Description This technique utilized the HemiCap Wave Implant manufactured by Anika Therapeutics (Franklin, MA, USA). A standard midline approach and medial parapatellar arthrotomy is performed. The patella is everted, and the trochlea is exposed. A guide pin is placed perpendicular to the trochlear bony surface and centrally in the defect. The pin is advanced, and the surrounding area is reamed. A guide block is placed over the pin in the trochlea and over-reamed. The area is prepared and centrally drilled, then tapped. A taper post is implanted. The trochlear implant is then secured to the taper post with an impactor and mallet. On the patellar side, a guide pin is placed in the center of the patella. Consideration is given to medialization of the button to decrease Q-angle. The patella is reamed to the diameter of an appropriately sized patellar button. A trial button is used to ensure satisfactory tracking. A real patellar implant is then cemented into place. Standard closure is performed. Results Overall outcomes following inlay patellofemoral arthroplasty have been positive, with up to 89% of patients engaging in sports at 2 years status post surgery and 83% survival free of total knee arthroplasty at 5 years postoperatively. Discussion/Conclusion Patellofemoral arthroplasty can provide good satisfaction and high rates of return to sport in patients with symptomatic, isolated patellofemoral arthritis. The surgical technique video presented provides reproducible steps, tips, and tricks for performing this procedure.
Chapter
Treatment of symptomatic, isolated, localized, full-thickness, femoral cartilage defects in middle-aged active patients is a challenge due to poor cartilage healing capacity and frequently disabling symptoms [1]. Also such cartilage lesions can progress into osteoarthritis (OA) [2]. Biological treatment options such as marrow stimulation and chondrocyte transplantation are influenced by patient age and have less favourable outcomes with increasing patient age [3, 4]. Total and unicompartmental knee arthroplasty are typically not indicated for these patients due to only a limited area of the knee having significant cartilage loss [5, 6]. Normally non-operative treatment modalities are employed for these patients with physiotherapy, weight loss, analgesics and activity modification. But non-operative management is in some cases ineffective or fails over time. In these cases surgical treatment with a resurfacing implant is a potential treatment option.
Chapter
Mini-metal implants are indicated for treatment of symptomatic focal chondral or osteochondral defects in patients considered too old for biological reconstruction or too young with limited cartilage defects for knee arthroplasty. This chapter reviews the three current options, HemiCAP/UniCAP (Arthrosurface Inc., Franklin, Massachusetts, USA), Episealer (Episurf, Sweden), and the BioPoly RS Knee system (Schwartz Biomedical, Fort Wayne, USA) describing their design, surgical technique for implantation, and rehabilitation. Precise surgical techniques are required to ensure optimal positioning with recession below the articular cartilage height. Long-term results are limited. Ten-year results of the HemiCAP and UniCAP implants show a 40% and 60% revision rate, respectively; however quantification of tibial articular surface wear was not reported. Where the implant survives, however, clinical function is high, and other papers report much better results. Early results from the BioPoly implant and the Episealer implant are more encouraging with low failure rates.
Article
Full-text available
To compare clinical and radiographic results after isolated patellofemoral arthroplasty (PFA) using either a second-generation inlay or onlay trochlear design. The hypothesis was that an inlay design will produce better clinical results and less progression of tibiofemoral osteoarthritis (OA) compared to an onlay design. Fifteen consecutive patients undergoing isolated PFA with an onlay design trochlear component (Journey™ PFJ, Smith & Nephew) were matched with 15 patients after isolated PFA with an inlay design trochlear component (HemiCAP(®) Wave, Arthrosurface). Matching criteria were age, gender, body mass index, and follow-up period. An independent observer evaluated patients prospectively, whereas data were compared retrospectively. Clinical outcome was assessed using WOMAC, Lysholm score, and pain VAS. Kellgren-Lawrence grading was used to assess progression of tibiofemoral OA. Conversion to total knee arthroplasty was necessary in one patient within each group, leaving 14 patients per group for final evaluation. The mean follow-up was 26 months in the inlay group and 25 months in the onlay group (n.s.). Both groups displayed significant improvements of all clinical scores (p < 0.05). No significant differences were found between the two groups with regard to the clinical outcome and reoperation rate. No significant progression of tibiofemoral OA was observed in the inlay group, whereas 53 % of the onlay group showed progression of medial and/or lateral tibiofemoral OA (p = 0.009). Isolated PFA using either a second-generation inlay or onlay trochlear component significantly improves functional outcome scores and pain. The theoretical advantages of an inlay design did not result in better clinical outcome scores; however, progression of tibiofemoral OA was significantly less common in patients with an inlay trochlear component. This implant design may therefore improve long-term results and survival rates after isolated PFA. III.
Article
Full-text available
To prospectively evaluate the clinical, radiographic, and sports-related outcomes at 24 months after isolated and combined patellofemoral inlay resurfacing (PFIR). Between 2009 and 2010, 29 consecutive patients with patellofemoral osteoarthritis (OA) were treated with the HemiCAP(®) Wave Patellofemoral Resurfacing System (Arthrosurface, Franklin, MA, USA). Based on preoperative findings, patients were divided into two groups: group I, isolated PFIR (n = 20); and group II, combined PFIR with concomitant procedures to address patellofemoral instability, patellofemoral malalignment, and tibiofemoral malalignment (n = 9). Patients were evaluated preoperatively and at 24 months postoperatively. Clinical outcomes included WOMAC, subjective IKDC, Pain VAS, Tegner activity score, and a self-designed sports questionnaire. Kellgren-Lawrence grading was used to assess progression of tibiofemoral OA. The Caton-Deschamps Index was used to assess differences in patellar height. Twenty-seven patients (93 %) were available for 24-month follow-up. Eighty-one per cent of the patients were either satisfied or very satisfied with the overall outcome. Significant improvements in the WOMAC, subjective IKDC, and Pain VAS were seen in the overall patient cohort and in both subgroups. The median Tegner score and sports frequency showed a significant increase in the overall patient cohort and in group II. The number of sports disciplines increased significantly in both subgroups. No significant progression of tibiofemoral OA or changes in patellar height were observed. Patellofemoral inlay resurfacing is an effective and safe procedure in patients with symptomatic patellofemoral OA. Significant improvements in functional scores and sports activity were found after both isolated and combined procedures. Prospective case series, Level III.
Article
We have developed a 12-item questionnaire for patients having a total knee replacement (TKR). We made a prospective study of 117 patients before operation and at follow-up six months later, asking them to complete the new questionnaire and the form SF36. Some also filled in the Stanford Health Assessment Questionnaire (HAQ). An orthopaedic surgeon completed the American Knee Society (AKS) clinical score. The single score derived from the new questionnaire had high internal consistency, and its reproducibility, examined by test-retest reliability, was found to be satisfactory. Its validity was established by obtaining significant correlations in the expected direction with the AKS scores and the relevant parts of the SF36 and HAQ. Sensitivity to change was assessed by analysing the differences between the preoperative scores and those at follow-up. We also compared change in scores with the patients’ retrospective judgement of change in their condition. The effect size for the new questionnaire compared favourably with those for the relevant parts of the SF36. The change scores for the new knee questionnaire were significantly greater (p < 0.0001) for patients who reported the most improvement in their condition. The new questionnaire provides a measure of outcome for TKR that is short, practical, reliable, valid and sensitive to clinically important changes over time.
Article
Patellofemoral arthroplasty can be an effective intermediate treatment for the patient with isolated arthritis of the anterior compartment of the knee. In the absence of patellar malalignment, results are optimized when an implant with sound geometric features is used, the prosthesis is appropriately aligned, and the soft tissues are balanced. Although previous prosthesis designs resulted in a relatively high prevalence of failure because of patellofemoral maltracking, patellofemoral catching, and anterior knee pain, newer prosthesis designs show promise in reducing the prevalence of patellofemoral dysfunction. Progressive tibiofemoral cartilage degeneration is another so-called failure mechanism; such progressive degeneration underscores the importance of restricting the procedure to patients who do not have tibiofemoral chondromalacia. Because long-term failure as a result of tibiofemoral degeneration may occur in approximately 25% of patients, patellofemoral arthroplasty may be considered an intermediate procedure for select patients with patellofemoral arthritis.
Article
We present a prospective review of the outcome of 76 Lubinus patellofemoral arthroplasties carried out in 59 patients between 1989 and 1995. At a mean follow-up of 7.5 years, 62 knees in the 48 patients were reviewed; 11 patients (14 knees) had died. None was lost to follow-up. The clinical outcome using the Bristol Knee Scoring system was satisfactory in 45% of the cases. Maltracking of the patella, resulting in lateral tilt, subluxation and polyethylene wear, was the most common complication (32%). Revision surgery was carried out in 21 knees (28%) giving a cumulative survival rate of 65% (confidence interval (CI) 49 to 77) at eight years. The survival rate for revision and moderate pain was 48% (CI 36 to 59) at six years. Progression of arthritis was seen in seven cases (9%). In five of these (6.5%), the symptoms were severe enough to need revision surgery. Due to the high proportion of unsatisfactory results, we have discontinued the use of this prosthesis.
Article
Isolated patellofemoral osteoarthritis is not uncommon. Surgical treatment of isolated patellofemoral arthritis remains controversial and poses a challenging treatment dilemma. The present study aimed to evaluate the short-term results of patellofemoral arthroplasty for patients with isolated patellofemoral osteoarthritis. We analyzed 11 patellofemoral arthroplasties performed from March 2006 to September 2009 in 11 patients with isolated patellofemoral arthritis. The patients comprised 2 males and 9 females with an average age of 53.7 years (range, 46 - 74 years). Standard weightbearing radiographs were taken in the anteroposterior, lateral, and 45° axial views. The knee pain and functional status were evaluated by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scales and American Knee Society (AKS) scores. For comparison, 23 total knee arthroplasties in 23 patients with primary tibiofemoral osteoarthritis were matched according to age, gender, bilaterality and body mass index. The duration of follow-up was 23.7 months (range, 12 - 47 months). The majority of the 11 patients experienced improvement in their patellofemoral symptoms after patellofemoral arthroplasty. The WOMAC scores improved considerably by 7.4 points with respect to pain and by 5.2 points with respect to function. The AKS scores also improved considerably by 23.9 points with respect to pain and 44.3 points with respect to function. Although the clinical outcomes after patellofemoral arthroplasty were not better than those after total knee arthroplasty, patellofemoral arthroplasty exhibited advantages in the shorter operation time, lower blood loss and increased postoperative range of motion. At the latest follow-up, there was no clinical or radiographic evidence of patellofemoral maltracking, loosening or wear. On the basis of our experience in this relatively small series of patients with a short-term follow-up, patellofemoral arthroplasty is an effective treatment alternative to total knee arthroplasty in isolated patellofemoral arthritis. MRI and arthroscopy may contribute to define those patients with isolated patellofemoral degeneration.
Article
Between May 1998 and May 2007 we carried out 50 Avon patellofemoral joint replacements in 32 patients with isolated patellofemoral osteoarthritis. There were no revisions in the first five years, giving a cumulative survival of 100% for those with a minimum follow-up of five years. The mean follow-up was 5.3 years (2.1 to 10.2). The median Oxford knee score was 30.5 (interquartile range 22.25 to 42.25). In patients with bilateral replacements the median Euroqol General health score was 50 which was significantly lower than that of 75 in those with a unilateral replacement (p = 0.047). The main complication was progression of disease, which was identified radiologically in 11 knees (22%). This highlights the need for accurate selection of patients. Our findings suggest that the Avon prosthesis survives well and gives a satisfactory functional outcome in the medium term.