Trunk, Hip and Knee Exercise Programs for Pain Relief, Functional Performance and Muscle Strength in Patellofemoral Pain: Systematic Review and Meta-Analysis

Figures & data

Figure 1 Search results.

Table 1 Summary of PEDro Scale Methodological Quality of the Included Studies

Author	I	II	III	IV	V	VI	VII	VIII	IX	X	Score (/10)
Studies included in the meta-analysis
Hott et al (2019)^Citation17	1	1	1	0	0	1	1	1	1	1	8
Saad et al (2018)^Citation18	1	1	1	0	0	1	1	1	1	1	8
Fukuda et al (2012)^Citation10	1	1	1	0	0	1	1	1	1	1	8
Hott et al (2020)^Citation33	1	1	1	0	0	1	1	1	1	1	8
Ismail et al (2013)^Citation35	1	1	1	0	0	1	1	1	1	1	8
Nakagawa et al (2008)^Citation36	1	1	1	0	0	1	1	1	0	1	7
Fukuda et al (2010)^Citation34	1	1	1	0	0	1	1	0	1	1	7
Dolak et al (2011)^Citation31	1	0	1	0	0	1	0	1	1	1	6
Sahin et al (2016)^Citation15	1	0	1	0	0	1	1	0	1	1	6
Ferber et al (2015)^Citation32	1	1	1	0	0	0	0	1	1	1	6
Ferber et al (2011)^Citation37	0	0	1	0	0	0	1	1	1	1	5
Willy et al (2011)^Citation39	1	0	1	0	0	0	1	0	1	1	5
Khayambashi et al (2014)^Citation8	0	0	1	0	0	0	1	0	1	1	4
Studies excluded from the meta-analysis due to lack or specific comparative groups
Steinberg et al (2019)^Citation41	1	1	1	0	0	1	1	1	1	1	8
Rabelo et al (2018)^Citation30	1	1	1	0	0	1	1	1	1	1	8
De Baldon et al (2014)^Citation40	1	1	1	0	0	0	1	1	1	1	7
Chevidikunnan et al (2016)^Citation28	1	1	1	0	0	0	1	1	1	1	7
Van Linschoten et al (2009)^Citation29	1	1	1	0	0	0	1	1	1	1	7
Khayambashi et al (2012)^Citation39	1	0	1	0	0	0	1	0	1	1	5
Foroughi et al (2019)^Citation42	1	0	1	0	0	0	0	0	1	1	4
Avraham et al (2007)^Citation45	1	0	0	0	0	1	0	0	1	0	3

Table 2 Inclusion and Exclusion Criteria, Outcome Measures, Compliance Rate and Main Findings of Included Studies

Author	Inclusion Criteria	Exclusion Criteria	Outcome Measures	Compliance	Findings
Hott et al (2019)^Citation17	16–40y; ≥3 month history of PFP ≥3 on VAS, reproduced by at least 2 activities (stair ascent/descent, hopping, running, prolonged sitting, squatting, kneeling) and present on at least 1 clinical test (compression of the patella, palpation of the patellar facets)	Clinical, radiographic, or MRI findings of meniscal, ligament, cartilage injury, osteoarthritis, epiphysitis, knee joint effusion, recurrent patellar subluxation or dislocation; pain from hip or back hindering the ability to perform exercises; surgery to the knee; nonsteroidal anti-inflammatory drug or cortisone use; trauma to the knee; physiotherapy or other similar exercises for PFP syndrome within the previous 3 months	AKPS, VAS, MVIC	92%	No difference in short-term effectiveness in combining patient education with knee-focused exer- cise, hip-focused exercise, or free training for patients with PFP.
Saad et al (2018)^Citation18	Insidious onset of symptoms; retropatellar or peripatellar pain with at least 2 of the following activities (ascending/descending stairs, running, kneeling, squatting, prolonged sitting or jumping)	History of knee surgery; history of back, hip, or ankle joint injury or pain; patellar instability; lesion or pain during palpation or test of any structure of knee; neurological involvement that would affect gait	AKPS, VAS, MVIC	NR	All treatment groups showed significant improvements on pain and AKPS score after intervention with no statistically significant differences between groups except when compared to the control group. Only hip and quadriceps groups demonstrated improvements in muscle strength and knee valgus angle during the step activities.
Fukuda et al (2012)^Citation10	PFP for ≥3 months and increasing pain in 2 or more activities that commonly provoke PFP: ascending and descending stairs, squatting, kneeling, jumping, long sitting, isometric knee extension contraction at 60° of knee flexion, pain on palpation of the medial and/or lateral facet of the patella; sedentary women; defined as not having practiced physical activity any day of the week for ≥6 months	Neurological disorder; injury to the lumbosacral region, hip, or ankle; rheumatoid arthritis, a heart condition, or previous surgery involving the lower extremities; pregnancy; use of corticosteroids or anti-inflammatories; patellar instability, patellofemoral dysplasia, meniscal or ligament tears, osteoarthritis, or tendinopathies	AKPS, VAS, LEFS	90%	Knee-stretching and -strength- ening exercises supplemented by hip posterolater- al musculature–strengthening exercises were more effective than knee exercises alone in improving long-term function and reducing pain in sedentary women with PFP.
Hott et al (2020)^Citation33	16–40y; ≥3 months history of PFP; pain score for worst pain intensity during previous week of ≥3 on VAS, reproduced by at least two of the following activities: stair ascent or descent; hopping, running, prolonged sitting, squatting or kneeling and present on at least one of the following clinical tests:compression of the patella or palpation of the patellar facets	Clinical, radiographic, or MRI findings of meniscal, ligament, cartilage injury, osteoarthritis, epiphysitis, knee joint effusion, recurrent patellar subluxation or dislocation; pain from hip or back hindering the ability to perform exercises; surgery to the knee; nonsteroidal anti-inflammatory drug or cortisone use; trauma to the knee; physiotherapy or other similar exercises for PFP syndrome within the previous 3 months	AKPS, VAS, MVIC	90%	After one year, there was no difference in effectiveness of knee exercise, hip exercise or free physical activity, when combined with patient education in PFP.
Ismail et al (2013)^Citation35	Anterior or retropatellar knee pain from at least 2 of the following activities regardless of the level of pain intensity prolonged sitting, stair climbing, squatting, running, kneeling and hopping/jumping; insidious onset of symptoms unrelated to a traumatic incident and persistent for ≥6w; had not previously received physical therapy	Meniscal or other intra articular pathologic conditions; cruciate or collateral ligament involvement; patellar subluxation or dislocation; previous surgery in the knee and hip joints; knee and hip joints osteoarthritis; any conditions affects muscle strength like diabetes mellitus or rheumatoid arthritis	AKPS, VAS, MVIC	NR	Six weeks closed kinetic chain program focusing on knee and hip strengthening has similar effect in improving hip muscles torque in patients with PFP as a closed kinetic chain exercises with additional hip strengthening exercises. However, adding isolated hip strengthening exercises has the advantage of more pain relief.
Nakagawa et al (2008)^Citation36	Anterior or retropatellar knee pain during at least three of the following activities: ascending/descending stairs, squatting, running, kneeling, hopping/jumping and prolonged sitting; the insidious onset of these symptoms being unrelated to a traumatic incident and persistent for ≥4w; presence of pain on palpation of the patellar facets, on stepping down from a 25-cm step, or during a double-legged squat	Meniscal or other intra-articular pathologic conditions; cruciate or collateral ligament involvement; tenderness over the patellar tendon, iliotibial band, or pes anserinus tendons; patellar apprehension; Osgood–Schlatter or Sinding– Larsen–Johansson syndromes; hip or lumbar referred pain; a history of patellar dislocation; evidence of knee joint effusion; or previous surgery on the patellofemoral joint	VAS, MVIC	NR	Supplementation of strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise programme provided additional benefits with respect to the perceived pain symptoms during functional activities in patients with PFP after 6 weeks of treatment.
Dolak et al (2011)^Citation31	Anterior or retropatellar knee pain during at least 2 of the activities of stair climbing, hopping, running, squatting, kneeling, and prolonged sitting; an insidious onset of symptoms not related to trauma; pain with compression of the patella; pain on palpation of patellar facets	Symptoms present for <1 month; cartilage injury or ligamentous tear; history of knee surgery within the last year; self-reported history of patella dislocations or subluxations; any other concurrent significant injury affecting the lower-extremity	VAS, LEFS, MVIC	80%	Both rehabilitation approaches improved function and reduced pain. For patients with PFP, initial hip strengthening may allow an earlier dissipation of pain than exercises focused on the quadriceps.
Fukuda et al (2010)^Citation34	Females aged 20–40y; history of anterior knee pain for ≥3 months and reported pain in 2 or more daily activities: ascending and descending stairs, squatting, kneeling, jumping, long sitting, isometric knee extension contraction at 60° of knee flexion; pain on palpation of the medial and/or lateral facet of the patella	Pregnancy; neurological disorders, hip or ankle injuries, low back or sacroiliac joint pain, rheumatoid arthritis; heart condition that precluded performing the exercises; previous surgery involving the lower extremities; patellar instability; patellofemoral dysplasia; meniscal or ligament tears; osteo- arthritis; tendinopathies; epiphysitis	AKPS, VAS, MVIC	NR	Rehabilitation programs focusing on knee strengthening exercises and knee strengthening exercises supplemented by hip strengthening exercises were both effective in improving function and reducing pain in sedentary women with PFP.
Sahin et al (2016)^Citation15	Sedentary females aged 20–45y; patients with a full ROM of the knee joints; presence of anterior or retropatellar knee pain during at least 3 of the following activities: ascending/descending stairs, squatting, hopping/running, prolonged sitting; insidious onset of symptoms unrelated to a traumatic incident and persistence of symptoms for at least 4 weeks; a score of ≥3 on the VAS; presence of pain on palpation of the patellar facets; presence of pain on stepping down from a 25-cm step or double-legged squat	Current significant injury affecting lower limb joints; surgery of the knee joint; signs or symptoms or MRI findings of intraarticular pathologic conditions such as effusion, meniscal, cruciate or collateral ligament involvement; tenderness of the patellar tendon or iliotibial band or pes anserinus tendon; patellar subluxation or dislocation; signs of patellar apprehension; referred pain with hip pain, or back pain; acute strain or sprain; current use of nonsteroid antiinflammatory drugs or corticosteroids	AKPS, VAS, MVIC	91%	The improvements of the patients in the hip-and-knee exercise group were better than in patients of the knee-only exercise group in terms of scores of pain relief and functional gain after 12 weeks.
Ferber et al (2015)^Citation32	≥3 on the VAS scale; insidious onset of symptoms unrelated to trauma; pain during at least 3 of the following activities: ascending/descending stairs, squatting, running, kneeling, jumping, and prolonged sitting; pain with palpation of the patellar facets; recreationally active (≥30 min/day, 3–4 days a week)	Meniscal or other intra-articular injury; cruciate or collateral ligament laxity or tenderness; patellar tendon, iliotibial band, or pes anserine tenderness; positive patellar-apprehension sign; Osgood-Schlatter or Sinding-Larsen-Johansson syndrome; evidence of effusion; hip or lumbar referred pain; history of recurrent patellar subluxation or dislocation; surgery to the knee; history of head injury or vestibular disorder within the last 6 months; pregnancy	AKPS, VAS, MVIC	81%	Although outcomes were similar, the HIP protocol resulted in earlier resolution of pain and greater overall gains in strength compared with the KNEE protocol.
Ferber et al (2011)^Citation37	Anterior or retropatellar knee pain, with a severity of ≥3 on VAS, during at least 2 of the following activities: ascending and descending stairs, hopping and running, squatting or kneeling, prolonged sitting; insidious onset of symptoms unrelated to trauma; pain with compression of the patella; pain on palpation of patellar facets	Unilateral symptoms present for >2 months; self-reported clinical evidence of other knee conditions; history of knee surgery; self-reported history of patellar dislocations or subluxations; current significant injury affecting other lower extremity joints	VAS, MVIC	NR	A 3-week hip-abductor muscle-strengthening protocol was effective in increasing muscle strength and decreasing pain and stride-to-stride knee-joint variability in individuals with PFP.
Willy et al (2011)^Citation39	Female runners aged 18–35y; running at least 10 km per week; excessive peak hip adduction during running	Free from any musculoskeletal sugrery that would affect their running or squatting mechanics	MVIC	100%	A training program that included hip strengthening and movement training specific to single-leg squatting did not alter running mechanics but did improve single-leg squat mechanics.
Khayambashi et al (2014)^Citation8	Peripatellar and/or retropatellar pain; reproduction of pain with activities commonly associated with this condition (eg, stair decent, squatting, kneeling, prolonged sitting)	Ligamentous laxity; meniscal injury; pes anserine bursitis; iliotibial band syndrome; patella tendinitis; history of patella dislocation; patella fracture; knee surgery; previous physical therapy; symptoms that had been present for <6 months	VAS, WOMAC	93%	Although both intervention programs resulted in decreased pain and improved function in persons with PFP, outcomes in the posterolateral hip exercise group were superior to the quadriceps exercise group.
Steinberg et al (2019)^Citation41	Full-time student in one of the dancing programs, diagnosed by one of two orthopedic surgeons as having PFP	Previous knee surgery	VAS, MVIC	NR	Both isometric exercises and somatosensory training were effective for decreasing clinical symptoms and improving some functional abilities in young dancers with PFP.
Rabelo et al (2018)^Citation30	Females aged 18–30y; PFP for ≥3 months related to at least 2 of the following activities: prologned sitting, climbing or descending stairs, squatting, kneeling or jumping; pain on palpation	History of surgery in the lower limbs; recurrent patellar instability; disorders associated with meniscal and/or ligamentous injuries; cardiac or locomotor disorders that could affect the assessment and treatment	AKPS, VAS, MVIC	NR	Movement control training was no more effective than the isolated strengthening protocol, in terms of pain, function, muscle strength, or kinematics.
De Baldon et al (2014)^Citation40	≥3 on the VAS scale; anterior or retropatellar knee pain during at least 3 of the following activities: ascending/descending stairs, squatting, running, kneeling, jumping, and prolonged sitting; an insidious onset of symptoms unrelated to trauma	Intra-articular pathology; involvement of cruciate or collateral ligaments; patellar instability; Osgood-Schlatter or Sinding- Larsen-Johansson syndrome; hip pain; knee joint effusion; surgery in the lower limb; pain on palpation of the patellar tendon, iliotibial band, or pes anserinus tendons	VAS, LEFS, MVIC	NR	An intervention program consisting of hip muscle strengthening and lower-limb and trunk movement control exercises was more beneficial in improving pain, physical function, kinematics, and muscle strength compared to a program of quadriceps-strengthening exercises alone.
Chevidikunnan et al (2016)^Citation28	Females aged 16–40y; PFP for ≥4 weeks that was aggravated by at least 2 of the following activities: jumping, running, prolonged sitting, stair climbing, kneeling, and squatting; positive patellar grinding test; must be active for at least 30 min/day	Cruciate, meniscal, collateral ligament injuries or tenderness; intra-articular injury; tenderness over the illiotibial band, patellar tendon, or pes anserine tendons; Sinding-Larsen-Johanssen syndromes or Osgood-Schlatter disease; evidence of joint effusion, referred pain from the hip or lumbar region, known case of articular cartilage damage	VAS	NR	Adding a core muscle-strengthening program to the conventional physical therapy management improves pain and dynamic balance in female patients with PFP.
Van Linschoten et al (2009)^Citation29	Pain during stair ascending or descending, squatting, running, cycling or when sitting with knees flexed for a prolonged period of time; grinding of the patella; positive clinical patellar test (Clark’s test)	Knee osteoarthritis; patellar tendinopathy; Osgood-Schlatter disease; other defined pathological conditions of the knee; previous knee injuries or surgery	VAS	NR	Supervised exercise therapy resulted in less pain and better function at short and long term follow-up compared with usual care in patients with PFP.
Khayambashi et al (2012)^Citation39	Peripatellar and/or retropatellar pain related to prologned sitting, climbing or descending stairs, squatting, kneeling or jumping	Ligamentous laxity; meniscal injury; pes anserine bursitis; iliotibial band syndrome; patellar tenidinitis; history of patellar dislocation or fracture; knee surgery	VAS, WOMAC, MVIC	NR	Isolated hip strengthening was effective in improving pain and health status in females with PFP compared with a control group with no intervention.
Foroughi et al (2019)^Citation42	Females aged 18–30y; PFP for ≥3 months related to prologned sitting, climbing or descending stairs, squatting, kneeling or jumping; pain on palpation, active ≥ 30 minutes/day	History of knee pathologies; history of patellar subluxation or dislocation; lumbopelvic-hip complex pathology; spinal or lower extremity fracture; knee surgery within the previous year; metabolic or neuromuscular disease	VAS, AKPS	NR	Greater pain relief and functional improvement has been shown in the Hip&Knee&Core group compared to the Hip&Knee group.
Avraham et al (2007)^Citation45	Positive PF gliding test; negative McMurry test; full ROM; pain related to prologned sitting, climbing or descending stairs	History of knee trauma; degenerative changes in the PFJ	VAS	60%	Hip&Knee, Hip only and Knee only exercise showed similar efficiency, with stronger significance to the groups who combined hip strengthening and stretching exercises.

Table 3 Exercise Programs Description

Author	N	Gender	Age	Type	Duration (Weeks)	Frequency (x Week)	Number of Exercises	Number of Sets	Repetitions	Progression
Studies included in the meta-analysis
Hott et al (2019)^Citation17	Hip (n=39)	Both	16–40	Strength	6	3	3	3	10–20	Yes Yes
	Knee (n=37)	Both	16–40	Strength	6	3	3	3	10–20
	Control (n=37)	Both	16–40	/	/	/	/	/	/	/
Saad et al (2018)^Citation18	Hip (n=10)	F	18–28	Strength	8	2	5	3	10	Yes
	Knee (n=10)	F	18–28	Strength	8	2	5	3	10	Yes
	Stretching (n=10)	F	18-28	Stretching	8	2	7	3	1	Yes
	Control (n=10)	F	18-28	/	/	/	/	/	/	/
Fukuda et al (2012)^Citation10	Hip&Knee (n=28)	F	20–40	Strength	4	3	10	3	10	Yes
	Knee (n=26)	F	20–40	Strength	4	3	6	3	10	Yes
Hott et al (2020)^Citation33	Hip (n=39)	Both	16–40	Strength	6	3	3	3	10–20	Yes
	Knee (n=37)	Both	16–40	Strength	6	3	3	3	10–20	Yes
	Control (n=37)	Both	16-40	/	/	/	/	/	/	/
Ismail et al (2013)^Citation35	Hip&Knee (n=16)	Both	18–30	Strength	6	3	6	1–2	10	Yes
	Knee (n=16)	Both	18–30	Strength	6	3	4	1	10	Yes
Nakagawa et al (2008)^Citation36	Hip&Knee (n=7)	Both	17–40	Strength	6	5	4	2	15	No
	Knee (n=7)	Both	17-40	Strength	6	5	3	3	10	No
Dolak et al (2011)^Citation31	Hip (n=17)	F	16–35	Strength	8	3	3–4	3	10	Yes
	Knee (n=16)	F	16-35	Strength	8	3	3–4	3	10	Yes
Fukuda et al (2010)^Citation34	Hip&Knee (n=21)	F	20–40	Strength	4	3	9	3	10	Yes
	Knee (20)	F	20-40	Strength	4	3	5	3	10	Yes
	Control (n=24)	F	20-40	/	/	/	/	/	/	/
Sahin et al (2016)^Citation15	Hip&Knee (n=25) Knee (n=25)	F	20–45	Strength	6	5	7	2	5–30	Yes
		F	20-45	Strength	6	5	5	2	5-30	Yes
Ferber et al (2015)^Citation32	Hip (n=111) Knee (n=88)	Both	NR	Strength	6	3	3-4	3	10–15	Yes
		Both	NR	Strength	6	3	3–5	3	10-15	Yes
Ferber et al (2011)^Citation37	Hip (n=15) Control (n=10)	Both	NR	Strength	3	7	2	3	10	No
		Both	NR	/	/	/	/	/	/	/
Willy et al (2011)^Citation39	Hip (n=10) Control (n=10)	F	18–35	Strength	6	3	2	2	10	Yes
		F	18-35	/	/	/	/	/	/
Khayambashi et al (2014)^Citation8	Hip (n=18) Knee (n=18)	Both	NR	Strength	8	3	2	3	20–25	Yes
		Both	NR	Strength	8	3	2	3	20–25	Yes
Studies excluded from the meta-analysis due to lack or specific comparative groups
Steinberg et al (2019)^Citation41	Hip&Knee (n=18)	F	12–15	Strength	12	3	7	3	10-20	Yes
	SST (n=18)	F	12–15	Balance	12	3	5	1	15	Yes
	Stretching (n=28)	F	12-15	Stretching	12	3	5	1	1	No
Rabelo et al (2018)^Citation30	Hip&Knee&SST (n=17)	F	18–30	Strength&SST	4	3	7	3	10-20	Yes
	Hip&KneeKnee (n=17)	F	18–30	Strength	4	3	7	3	10	Yes
De Baldon et al (2014)^Citation40	FST (n=15)	F	18-30	Strength&FST	8	3	8–10	2–5	12–20	Yes
	Knee (n=16)	F	18-30	Strength	8	3	6-8	2-3	12-20	Yes
Chevidikunnan et al (2016)^Citation28	Hip&Knee&Core (n=10)	F	16-40	Strength	4	3	4	1	20–23	Yes
	Hip&Knee (n=10)	F	16-40	Strength	4	3	3	1	20-23	Yes
Van Linschoten et al (2009)^Citation29	Hip&Knee (n=65)	Both	14–40	Strength	6	5	NR	NR	NR	Yes
	Control (n=66)	Both	14-40	/	/	/	/	/	/	/
Khayambashi et al (2012)^Citation39	Hip (n=14)	F	NR	Strength	8	3	2	3	20-25	Yes
	Control (n=14)	F	NR	/	/	/	/	/	/
Foroughi et al (2019)^Citation42	Hip&Knee&Core (n=17)	F	18-30	Strength	4	3	7	3-5	10	Yes
	Hip&Knee (n=16)	F	18-30	Strength	4	3	6	3-5	10	Yes
Avraham et al (2007)^Citation45	Hip&Knee (n=10)	Both	NR	Endurance	3	2	5	1	1	No No
	Hip (n=10)	Both	NR	Endurance	3	2	3	1	1
	Knee (n=10)	Both	NR	Endurance	3	2	2	1	1	No

Abbreviations: Hip, hip focused exercise program; Knee, knee focused exercise program, Hip&Knee, hip and knee focused exercise program, SST, somatosensory training, FST, functional stabilization training, NR, not reported.

Figure 2 Hip only or Hip&Knee exercise programs compared with Knee only exercise programs for pain relief (VAS).

Figure 3 Hip only or Hip&Knee exercise programs compared with Knee only exercise programs for function (AKPS; LEFS).

Figure 4 Hip only or Knee only exercise programs compared with controls for function (AKPS).

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