Table 1 Design characteristics of included studies
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). |