Background
Methods
Eligibility criteria
Search strategy
Study selection
Data extraction and synthesis
Methodological quality
Results
Study characteristics
Author, year of publication | Design | Setting | Sampling procedure | AKP method of ascertainment, definition | PFOA method of ascertainment, definition | Length of follow-up |
---|---|---|---|---|---|---|
Utting et al 2005 [18] | Retrospective unmatched case-control. | Hospital orthopaedic surgery (Bristol, UK). | Local arthroplasty database (?period).
Cases
Isolated PF arthroplasty for severe isolated PFOA.
Controls
medial TF unicompartmental arthroplasty. | Self-complete questionnaire. Recall of AKP as a child, teenager, or young adult. | Severe isolated PFOA requiring patellofemoral arthroplasty. | - |
Kannus et al 1999 [19] | Prospective follow-up of RCT. | Hospital orthopaedic outpatients (Tampere, Finland). | Consecutive patients with unilateral PFPS enrolled in RCT of conservative therapy (1987-1990). | Clinical interview, examination and plain x-ray. Retropatellar pain and crepitus with no other knee abnormalities. | Plain x-rays (AP, lateral, tunnel, tangential) and MRI. PFOA classified as none, mild, moderate, or severe for each imaging modality. | Mean 6.6 years. |
Nimon et al 1998 [20] | Prospective follow-up of case series. | Hospital orthopaedic outpatients (Oxford, UK). | Consecutive adolescent female patients with idiopathic AKP (1974-1980). | Clinical history, examination, plain x-ray. No specific definition provided (other definitive diagnoses excluded, all complained of pain on ascending/descending stairs, squatting, or prolonged sitting). | Plain x-rays (AP, lateral, skyline). No specific definition provided. | Mean 16 years (range 14-20). |
Imhoff & Boni 1989 [21] | Prospective follow-up of two case series. | Orthopaedic outpatients, (Zurich, Switzerland). | ?consecutive patients with PF pain undergoing conservative or surgical treatment (1953-1968). | Unclear. No specific definition provided. | Plain x-rays (views not specified). Films scored using a 4-point radiographic definition, based on that of Jäger & Wirth [25]. | Mean 23 years. |
Hvid et al 1981 [22] | Prospective follow-up of case series. | Hospital orthopaedics/diagnostic radiology (Nykøbing, Denmark). | Patients with chondromalacia patellae on arthrography (1972-1977). | Clinical history, physical examination, and arthrogram. No specific definition provided. "a significant clinical syndrome" of chondromalacia patellae. | Plain x-rays (frontal, lateral, axial [26]). No specific definition provided ("signs of arthrosis were searched for on all films") | Mean 5.7 years. |
Dexel et al 1980 [23] | Prospective follow-up of two case series. | Orthopaedic outpatients, (Zurich, Switzerland). | ?consecutive patients with PF pain undergoing conservative or surgical treatment (1953-1968). | Unclear. No specific definition provided. | Plain x-rays (views not specified). 4-point radiographic definition, based on that of Tapper & Hoover [27]. | Mean 13 years. |
Karlson 1939 [24] | Prospective follow-up of comparative case series. | Hospital orthopaedics (Stockholm, Sweden). | ? consecutive male patients (mostly army conscripts) with "simple chondromalacia patellae" of both traumatic and non-traumatic origin (1917-1934). | Clinical history and physical examination. No specific definition provided. | Plain x-rays (views not specified). No specific definition provided ("arthritis deformans"). | Mean 5.9 years (range 1-20). |
Quality criteria | Utting et al 2005[18] | Kannus et al 1999[19] | Nimon et al 1998[20] | Imhoff & Boni 1989[21] | Hvid et al 1981[22] | Dexel et al 1980[23] | Karlson 1939[24] |
---|---|---|---|---|---|---|---|
Purpose clearly stated | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
Literature review relevant | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
Study design appropriate to study aims | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
No bias present | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Sample described in detail | 1 | 0 | 0 | 0 | 1 | 1 | 0 |
Sample size justified | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Informed consent gained | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Valid outcome measures used | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
Reliable outcome measures used | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Results reported in terms of statistical significance | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
Analysis appropriate | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Clinical importance of results reported | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
Appropriate conclusions | 1 | 1 | 1 | 0 | 1 | 0 | 0 |
Clinical implications reported | 0 | 1 | 1 | 1 | 1 | 1 | 0 |
Limitations of study acknowledged | 1 | 1 | 0 | 0 | 1 | 0 | 0 |
Total
|
9
|
8
|
8
|
5
|
11
|
5
|
3
|
Study results
Author, year of publication | N | Follow-up rate | Participant characteristics at baseline | Association between AKP and PFOA | Other findings | Quality score (0-15) |
---|---|---|---|---|---|---|
Utting et al 2005 [18] | 234 (118 cases, 116 controls). | Response rate 78% (cases 79%, controls 77%). |
Cases
90%F mean age at time of arthroplasty 67.3 years (range 44-87).
Controls: 82%F mean age at time of arthroplasty 68.3 years (range 48-86). | Crude OR = 4.4 (95%CI 1.8, 10.6) | Prior history of AKP (22% vs 6%), PF instability (14% vs 1%), and patella trauma (16% vs 6%) among cases. No difference in mean age at onset of AKP (18.1 vs 19.4 years). | 9 |
Kannus et al 1999 [19] | 37 | 70% |
Based on 49 potentially eligible participants:
53% F Mean age 27 years (range 15-50). Mean duration of symptoms 16 months (SD 19). | - | PFOA at follow-up (mean 6.6 years). On plain x-ray: mild 16%, moderate 0%, severe 3% On MRI: mild 11%, moderate 19%, severe 5%. Estimated annual risk of PFOA 2.9%. | 8 |
Nimon et al 1998 [20] | 8 | 13% |
Based on 63 potentially eligible patients:
100%F Mean age 15.5 years (range 10-19). | - | Plain x-rays "normal" on participants imaged at follow-up (mean 16 years). Estimated annual risk of PFOA 0%. | 8 |
Imhoff & Boni 1989 [21] | 29 | 19% | 55%F Mean age at diagnosis 23 years (range 7-52). 11 had a history of knee trauma. | - | PFOA at follow-up (mean 23 years): Small superior patellar osteophytes (31%), joint space narrowing/ ↑ osteophytes/subchondral sclerosis 10.3%, joint space obliteration/cystic changes 6.9%. Estimated annual risk of PFOA 2.1%. | 5 |
Hvid et al 1981 [22] | 22 | 100% (?) | 60%F Mean age 27 years (range 14-44). Mean duration of symptoms 7.6 years (range 4-16). | - | No arthrosis in any participant at follow-up (mean 5.7 years). Estimated annual risk of PFOA 0%. | 11 |
Dexel et al 1980 [23] | 25 | 15% | 32%F Mean age 25 years (range 15-52). 5 had a history of post-traumatic patellar chondropathy. | - | Moderate or severe changes consistent with PFOA at follow-up (mean 13 years) 12%. Estimated annual risk of PFOA 0.9%. | 5 |
Karlson 1939 [24] | 35 | 31% |
Based on 71 potential eligible patients:
0%F 11% aged <20 years, 80% 20-29, 8% 30-59. | - | "very slight" arthritis deformans at follow-up (mean 5.9 years) 20%. Estimated annual risk of PFOA 3.4%. | 3 |